Arctic Sea Ice : Forum

AGW in general => Science => Topic started by: AbruptSLR on July 05, 2015, 11:24:49 PM

Title: Modelling the Anthropocene
Post by: AbruptSLR on July 05, 2015, 11:24:49 PM
With a refreshed perspective from my 6-week break from posting, I have decided to focus for a while on emphasizing the nature, reality and implications of the Anthropocene; as examining mankind's decision making processes can no longer be marginalized by science if we are to reasonably understand our increasingly dominant impact on nature.  In this light, I have made new posts to:  "The Early Anthropocene" thread (here: http://forum.arctic-sea-ice.net/index.php/topic,852.0.html (http://forum.arctic-sea-ice.net/index.php/topic,852.0.html) ); and I am opening three new threads in this Science Folder, beginning with this thread on "Modelling the Anthropocene", as well as two other threads entitled: "Anthropogenic Existential Risks" (here: http://forum.arctic-sea-ice.net/index.php/topic,1307.0.html (http://forum.arctic-sea-ice.net/index.php/topic,1307.0.html) ) and "Adapting to the Anthropocene" (here: http://forum.arctic-sea-ice.net/index.php/topic,1308.0.html (http://forum.arctic-sea-ice.net/index.php/topic,1308.0.html) ). 
This new "Modelling the Anthropocene" thread expands beyond the hard physical science's examination of the Anthropocene, to embrace what the Germans call Geisteswissenschaften, or "human sciences"; within the rigorous, reasoned framework of coupled socioeconomic & climate change models.  This thread was inspired by the new Shared Socioeconomic Pathways (SSPs) currently being developed within the IPCC's framework to interact with the Recommended Concentration Pathways (RCPs).  However, I plan to expand beyond the IPCC framework to discuss such topics as: information technology, social science, economic theory, political science, palaeoenvironmental sciences, historiography, etc. all of which help us to understand the past (also see the "Defining the Anthropocene" thread), and to model the future, Anthropocene Era. 
To put the Anthropocene into perspective, the linked article by Joe Romm, points out that in 1995 Richard Leaky warned that homo sapiens is now the greatest agent for global catastrophe and is the most likely cause of the ongoing Holocene Extinction (The Sixth Extinction), which, puts the human species at risk of extinction (also see the "Existential Risk for Mankind" thread).
http://thinkprogress.org/climate/2015/06/01/3653348/sixth-extinction/ (http://thinkprogress.org/climate/2015/06/01/3653348/sixth-extinction/)
Extract: "“Homo sapiens is poised to become the greatest catastrophic agent since a giant asteroid collided with the Earth 65,000,000 years ago, wiping out half the world’s species in a geological instant.” So wrote anthropologist Richard Leakey in his 1995 book, “The Sixth Extinction: Patterns of Life and the Future of Humankind.”
Because of the vital dependence we have on the “ecosystem services” provided by the rest of nature, Leakey warned, “unrestrained, Homo sapiens might not only be the agent of the sixth extinction, but also risks being one of its victims.”"
To add prospective to the risks that mankind is taking that it might fall victim to "The Sixth Extinction", I provide the first attached image from the World Wildlife Fund that shows that Homo sapiens already use the equivalent of 1.5 Earths to support our consumption.

(see the first attached image)

For further perspective on why such an interdisciplinary (Geisteswissenschaften) consideration of the Anthropocene is merited, I provide the following link & extracts from the Slate article by Brad Allenby and Daniel Sarewitz (January 2015), "There’s No Place Like Home: Science, information, and politics in the Anthropocene", or: "Toto, we’re not in an era of simple scientific experimentation anymore."

http://www.slate.com/articles/technology/future_tense/2015/01/science_information_and_politics_in_the_anthropocene_or_the_age_of_humans.html (http://www.slate.com/articles/technology/future_tense/2015/01/science_information_and_politics_in_the_anthropocene_or_the_age_of_humans.html)

Extract: "First: Science ain’t what it used to be. Our ideal of science is of a highly structured activity for establishing cause-and-effect relationships that can be tested in the field and the laboratory. Now the focus is increasingly on computational models and scenarios aimed at exploring complex phenomena (such as climate change) that unfold on scales from the global to the molecular. Second: Information, which used to be scarce and closely guarded, is now everywhere, accessible to everyone. Once, the Catholic Church had a lock on what counted as knowledge and its interpretation. Then scientists took over. Today no individual or institution can ever have a monopoly on knowledge or expertise. Third: Therefore, the boundary between authoritative knowledge on one hand, and the subjective worlds of policy, ethics, and even religion on the other, grows increasingly fuzzy and meaningless. 
Taken individually, any of these changes would be a significant challenge to our current models of rational policymaking based on scientific principles; as a whole, they signal the most profound shift in social and cultural understanding of the role of science since the Scientific Revolution and the early Enlightenment, with its emphasis on formal knowledge as a basis for solving problems.

...

No one can replicate global environmental conditions in such a way as to experimentally test climate change. For such complex systems, the best we can do is create complicated computer models. But creating a model necessarily involves generating a set of rules that determines what we include in the model and what we exclude. And any set of rules that enables us to model a complex system that is coherent necessarily gives us a model that is partial and arbitrary—hence the common refrain that “all models are wrong, but some are useful.” We can use the model to generate multiple scenarios of the future that are consistent with scientific understanding, but we cannot have the underlying system itself. The complexity of the Anthropocene—in which, for example, climate change is an emergent phenomenon of 300 years of industrialism—is not subject to the sort of verifiable and predictive understanding that characterized science of the sort that Copernicus, Newton, or even Einstein practiced.
….
Does anyone out there think that radically transforming the global energy system will be easier and more predictable than turning Iraq into a democracy? Or that the evidence for doing so is more compelling than the evidence in favor of eliminating Saddam Hussein? Remember, in the Anthropocene, everything is more complicated. Our computer models can give us a thousand scenarios of how the climate may change. But remember that global warming is an unintended consequence of 300 years of industrialism—why would we think that equally momentous unintended consequences would not accompany the enormous social changes pursued in our effort to control the future behavior of the climate?
There is indeed a cruel dilemma here: In order for the science to matter, it must be heard; in order to be heard, it must be translated into catastrophic visions and simplistic policy formulations that are literally absurd abstractions of the complexity that we inhabit. Thus, the third condition of the Anthropocene: Science moves from being a mutually accepted foundation for debating action in the world to being the tool of one or another group of partisans, wielded in the settings of politics as if it were as clear and inescapable as the equations that Newton used to describe falling objects. The necessary oversimplification, urgent appeal to fear and insecurity, insistence on predictive certainty, and direct linkage to an explicit social agenda that would create huge new groups of winners and losers (and is thus inherently divisive) obliterate the boundary between science and politics.
What we will need above all to manage complexity in the Anthropocene is humility all around. We are not in Kansas anymore, where things are simple, the truth is clear, and we know what we know. Everything really is connected to everything else now, and the biggest mistake we can make is to focus too narrowly on one thing or one way of doing things. That’s the most important lesson of the abject failure of climate change policy and politics, and it’s one that we must learn if we are to effectively confront the new world that we have and will continue to create. Climate change is not a problem of our old way of doing things—it’s a symptom of our new condition."

For the end of this first post in this "Modelling the Anthropocene" thread, I note that the second attached image illustrates how risk is the product of probability (frequency) times (X) consequences (magnitude); therefore the greatest risk to society lays well to the right of the most probable climate change scenario.  I note that the scientific consensus probability density function, PDF, for global warming may likely skew to the right as: (a) we continue on an unsustainably high pathway for anthropogenic radiative forcing and (b) we learn more about the probabilities of high climate sensitivity.  Lastly, I note that the scientific consensus slope of the consequence curve may likely become steeper, particularly as more scientists acknowledge the true risks of abrupt sea level rise, ASLR.
 

Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on July 06, 2015, 12:20:31 AM
The first linked reference (& associated images) discusses the Shared Socioeconomic Pathways (SSPs) & world hunger.  The SSPs are formulated to be used with the RCPs & the Hasegawa (2015) emphasizes that to provide more food supply, more refrigeration & transportation will be used which will further accelerate climate change:

Tomoko Hasegawa et al (2015), "Scenarios for the risk of hunger in the twenty-first century using Shared Socioeconomic Pathways", Environ. Res. Lett. 10 014010

http://iopscience.iop.org/1748-9326/10/1/014010/article (http://iopscience.iop.org/1748-9326/10/1/014010/article)
http://iopscience.iop.org/1748-9326/10/1/014010/pdf/1748-9326_10_1_014010.pdf (http://iopscience.iop.org/1748-9326/10/1/014010/pdf/1748-9326_10_1_014010.pdf)

Abstract: "Shared socioeconomic pathways (SSPs) are being developed internationally for cross-sectoral assessments of climate change impacts, adaptation, and mitigation. These are five scenarios that include both qualitative and quantitative information for mitigation and adaptation challenges to climate change. In this study, we quantified scenarios for the risk of hunger in the 21st century using SSPs, and clarified elements that influence future hunger risk. There were two primary findings: (1) risk of hunger in the 21st-century greatly differed among five SSPs; and (2) population growth, improvement in the equality of food distribution within a country, and increases in food consumption mainly driven by income growth greatly influenced future hunger risk and were important elements in its long-term assessment."

See also:
http://environmentalresearchweb.org/cws/article/news/60936# (http://environmentalresearchweb.org/cws/article/news/60936#)
https://www2.cgd.ucar.edu/research/iconics/publications/ssps (https://www2.cgd.ucar.edu/research/iconics/publications/ssps)


Extract: "SSP1, a scenario of "sustainability" assumes low population growth, high economic growth, and good education and governance, as well as high levels of international cooperation, technological development and environmental awareness. The "fragmentation" scenario SSP3, on the other hand, shows a world where population growth is high but economic growth is low and there are regionalization, low levels of education and governance, and low environmental awareness. SSP2 lies midway between SSP1 and SSP3, while SSP4 is a scenario of inequality and assumes high-income countries have an SSP1 type-outlook whilst low-income countries experience SSP3. Finally, SSP5 sees low population growth, high economic growth and high human development but low environmental awareness and great dependence on fossil fuels.
"Scenarios for the risk of hunger in this study were more optimistic than those in existing research," said Hasegawa. "One reason was the incorporation of improved equality of food distribution, which was not previously considered. This indicates that inequality of food distribution greatly influences long-term assessments of hunger risk."

The SSPs do not include climate change but can be combined with representative concentration pathways (RCPs) to account for differences in climate change and climate policy. Other researchers have combined models of climate with agricultural and economic models to assess how climate change is likely to affect food supply; this approach does not allow for social welfare, political and institutional factors, however."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on July 06, 2015, 12:31:12 AM
For more background on the IPCC's Shared Socioeconomic Pathways, SSPs, I provide the following linked information:
http://environmentalresearchweb.org/cws/article/yournews/61208 (http://environmentalresearchweb.org/cws/article/yournews/61208)
Extract: "Climate experts will meet near Vienna, Austria, on 18-20 May 2015 at an Expert Meeting of the Intergovernmental Panel on Climate Change (IPCC) to discuss and further develop new socioeconomic scenarios as shared tools for climate research.
Experts from the climate change research community will meet with representatives of the IPCC at the meeting hosted by the International Institute for Applied Systems Analysis (IIASA) in Laxenburg, Austria."
Shared Socioeconomic Pathways (SSP):
https://secure.iiasa.ac.at/web-apps/ene/SspDb/dsd?Action=htmlpage&page=about (https://secure.iiasa.ac.at/web-apps/ene/SspDb/dsd?Action=htmlpage&page=about)
SSP Database, 2012 - 2015
Available at: https://tntcat.iiasa.ac.at/SspDb (https://tntcat.iiasa.ac.at/SspDb)

See also:
http://www.iiasa.ac.at/web/home/about/news/150518-IPCC-scenarios.html (http://www.iiasa.ac.at/web/home/about/news/150518-IPCC-scenarios.html)
http://www.iiasa.ac.at/web/home/research/researchPrograms/Energy/150518_IPCC_Scenarios_Expert_V2.html (http://www.iiasa.ac.at/web/home/research/researchPrograms/Energy/150518_IPCC_Scenarios_Expert_V2.html)


Elmar Kriegler, Jae Edmonds, Stéphane Hallegatte, Kristie L. Ebi, Tom Kram, Keywan Riahi, Harald Winkler, Detlef P. van Vuuren (2014), "A new scenario framework for climate change research: the concept of shared climate policy assumptions", Climatic Change , Volume 122, Issue 3, pp 401-414, DOI: 10.1007/s10584-013-0971-5


http://link.springer.com/article/10.1007%2Fs10584-013-0971-5 (http://link.springer.com/article/10.1007%2Fs10584-013-0971-5)

Abstract: "The new scenario framework facilitates the coupling of multiple socioeconomic reference pathways with climate model products using the representative concentration pathways. This will allow for improved assessment of climate impacts, adaptation and mitigation. Assumptions about climate policy play a major role in linking socioeconomic futures with forcing and climate outcomes. The paper presents the concept of shared climate policy assumptions as an important element of the new scenario framework. Shared climate policy assumptions capture key policy attributes such as the goals, instruments and obstacles of mitigation and adaptation measures, and introduce an important additional dimension to the scenario matrix architecture. They can be used to improve the comparability of scenarios in the scenario matrix. Shared climate policy assumptions should be designed to be policy relevant, and as a set to be broad enough to allow a comprehensive exploration of the climate change scenario space."


Also for another example of the food supply risks through 2040, see:

http://www.independent.co.uk/environment/climate-change/society-will-collapse-by-2040-due-to-catastrophic-food-shortages-says-study-10336406.html (http://www.independent.co.uk/environment/climate-change/society-will-collapse-by-2040-due-to-catastrophic-food-shortages-says-study-10336406.html)

Extract: "A scientific model has suggested that society will collapse in less than three decades due to catastrophic food shortages if policies do not change.
The model, developed by a team at Anglia Ruskin University’s Global Sustainability Institute, does not account for society reacting to escalating crises by changing global behaviour and policies.
However the model does show that our current way of life appears to be unsustainable and could have dramatic worldwide consequences."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on July 06, 2015, 12:34:09 AM
The following two linked sources discuss other Social-Ecological System Dynamics Modeling Efforts


JA Dearing et al (31 March 2015), "Social-ecological systems in the Anthropocene: The need for integrating social and biophysical records at regional scales", The Anthropocene Review, doi:10.1177/2053019615579128.

http://anr.sagepub.com/content/early/2015/04/24/2053019615579128.abstract (http://anr.sagepub.com/content/early/2015/04/24/2053019615579128.abstract)

Abstract: "Understanding social-ecological system dynamics is a major research priority for sustainable management of landscapes, ecosystems and resources. But the lack of multi-decadal records represents an important gap in information that hinders the development of the research agenda. Without improved information on the long-term and complex interactions between causal factors and responses, it will be difficult to answer key questions about trends, rates of change, tipping points, safe operating spaces and pre-impact conditions. Where available long-term monitored records are too short or lacking, palaeoenvironmental sciences may provide continuous multi-decadal records for an array of ecosystem states, processes and services. Combining these records with conventional sources of historical information from instrumental monitoring records, official statistics and enumerations, remote sensing, archival documents, cartography and archaeology produces an evolutionary framework for reconstructing integrated regional histories. We demonstrate the integrated approach with published case studies from Australia, China, Europe and North America."


http://geographical.co.uk/opinion/item/490-neoliberal-nightmare (http://geographical.co.uk/opinion/item/490-neoliberal-nightmare)

Extract: "This is where ‘geography’ can make a difference by envisioning new political systems of governance, enabling collective action and with more equal distribution of wealth, resources and opportunities."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on July 06, 2015, 12:48:34 AM
Research shows that while people may enjoy uncertainties in their various pursuits; they do not like uncertainty in the things that they pay for.  Therefore, when modeling the Anthropocene Era it is critical identify the ever-growing probability of clear indisputable climate change consequence signal.

For decades the main climate change debate has focused on the modeling how much the global mean surface temperature will rise by either 2050 or 2100 (see discussion in the following to linked threads: http://forum.arctic-sea-ice.net/index.php/topic,1053.0.html (http://forum.arctic-sea-ice.net/index.php/topic,1053.0.html) & http://forum.arctic-sea-ice.net/index.php/topic,1020.0.html (http://forum.arctic-sea-ice.net/index.php/topic,1020.0.html) ).  However, most people do not think globally on a 100-yr scale, they think locally on no-better than an annual scale; which translated into meaning that people care about local weather events that have relatively high variability/uncertainties when forecasting over any given year (let alone over decades).

However, extreme local temperature events appear to increase exponentially with increasing global mean surface temperature, so that the probability of an extreme heat event doubles when GMT increases from 1.5C to 2C.  Furthermore, I note that while currently extreme climate change influenced increases water cycle events (droughts, floods, etc) are harder to separate from the natural variability; if solar radiation management is implemented after 2050, then one can expect the anthropogenic water cycle signal to accelerate in the same manner that steam builds-up in a covered pot even though one reduced the flame beneath the pot when one put the lid on the pot.

Furthermore, the linked reference indicates that sea level rise will provide the earliest time of emergence of the climate change signal from natural variability.

Shuang Yi, Wenke Sun, Kosuke Heki and An Qian (2015), "An increase in the rate of global mean sea level rise since 2010", Geophysical Research Letters, DOI: 10.1002/2015GL063902

http://onlinelibrary.wiley.com/doi/10.1002/2015GL063902/abstract?utm_content=buffer63d49&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer (http://onlinelibrary.wiley.com/doi/10.1002/2015GL063902/abstract?utm_content=buffer63d49&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer)

Abstract: "The global mean sea level (GMSL) was reported to have dropped 5 mm due to the 2010/11 La Niña and have recovered in one year. With longer observations, it is shown that the GMSL went further up to a total amount of 11.6 mm by the end of 2012, excluding the 3.0 mm/yr background trend. A reconciled sea level budget, based on observations by Argo project, altimeter and gravity satellites, reveals that the true GMSL rise has been masked by ENSO-related fluctuations and its rate has increased since 2010. After extracting the influence of land water storage, it is shown that the GMSL have been rising at a rate of 4.4 ± 0.5 mm/yr for more than three years, due to an increase in the rate of both land ice loss and steric change."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on July 06, 2015, 12:54:38 AM
The following reference (& associated image) provides an example of modelling the media "echo chamber" effect on the US climate policy networks:

Lorien Jasny, Joseph Waggle & Dana R. Fisher (2015), "An empirical examination of echo chambers in US climate policy networks", Nature Climate Change, doi:10.1038/nclimate2666

http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2666.html (http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2666.html)
or
http://www.nature.com/articles/nclimate2666.epdf?referrer_access_token=nSYWIAIgXTg3SbgGS9WZOtRgN0jAjWel9jnR3ZoTv0PyFjo3Oq2nQJln5FjBLk0cwwBSR3GffbfkzQczShetpWKobpiby_EuBhzqCbuXAf2VXNvLQ4qdtNGJnANCRSzb5hDqnE5efrOaMd3NOBGFoYtRDnHeavDrzovnm-AsiWWT36Bd5pgxuQ_-S3_qFKWOHB35fECpX0r63NswrymhDBgcpBNpIG3lDm7YbACIzkY%3D&tracking_referrer=thinkprogress.org (http://www.nature.com/articles/nclimate2666.epdf?referrer_access_token=nSYWIAIgXTg3SbgGS9WZOtRgN0jAjWel9jnR3ZoTv0PyFjo3Oq2nQJln5FjBLk0cwwBSR3GffbfkzQczShetpWKobpiby_EuBhzqCbuXAf2VXNvLQ4qdtNGJnANCRSzb5hDqnE5efrOaMd3NOBGFoYtRDnHeavDrzovnm-AsiWWT36Bd5pgxuQ_-S3_qFKWOHB35fECpX0r63NswrymhDBgcpBNpIG3lDm7YbACIzkY%3D&tracking_referrer=thinkprogress.org)

Abstract: "Diverse methods have been applied to understand why science continues to be debated within the climate policy domain. A number of studies have presented the notion of the ‘echo chamber’ to model and explain information flows across an array of social settings, finding disproportionate connections among ideologically similar political communicators. This paper builds on these findings to provide a more formal operationalization of the components of echo chambers. We then empirically test their utility using survey data collected from the community of political elites engaged in the contentious issue of climate politics in the United States. Our survey period coincides with the most active and contentious period in the history of US climate policy, when legislation regulating carbon dioxide emissions had passed through the House of Representatives and was being considered in the Senate. We use exponential random graph (ERG) modelling to demonstrate that both the homogeneity of information (the echo) and multi-path information transmission (the chamber) play significant roles in policy communication. We demonstrate that the intersection of these components creates echo chambers in the climate policy network. These results lead to some important conclusions about climate politics, as well as the relationship between science communication and policymaking at the elite level more generally."



See also:
http://thinkprogress.org/climate/2015/05/27/3662739/climate-change-echo-chambers/ (http://thinkprogress.org/climate/2015/05/27/3662739/climate-change-echo-chambers/)
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on July 07, 2015, 12:54:05 AM
The following linked reference has relatively cheery findings with regard to the stability of marine methane hydrates for the next 100-years; unless, Wallmann et al. (2012) proves to be too conservative w.r.t. projected methane emissions:

Kerstin Kretschmer, Arne Biastoch, Lars Rüpke & Ewa Burwicz (May 2015), "Modeling the fate of methane hydrates under global warming", Global Biogeochemical Cycles, DOI: 10.1002/2014GB005011

http://onlinelibrary.wiley.com/doi/10.1002/2014GB005011/abstract (http://onlinelibrary.wiley.com/doi/10.1002/2014GB005011/abstract)

Abstract: "Large amounts of methane hydrate locked up within marine sediments are vulnerable to climate change. Changes in bottom water temperatures may lead to their destabilization and the release of methane into the water column or even the atmosphere. In a multimodel approach, the possible impact of destabilizing methane hydrates onto global climate within the next century is evaluated. The focus is set on changing bottom water temperatures to infer the response of the global methane hydrate inventory to future climate change. Present and future bottom water temperatures are evaluated by the combined use of hindcast high-resolution ocean circulation simulations and climate modeling for the next century. The changing global hydrate inventory is computed using the parameterized transfer function recently proposed by Wallmann et al. (2012). We find that the present-day world's total marine methane hydrate inventory is estimated to be 1146 Gt of methane carbon. Within the next 100 years this global inventory may be reduced by ∼0.03% (releasing ∼473 Mt methane from the seafloor). Compared to the present-day annual emissions of anthropogenic methane, the amount of methane released from melting hydrates by 2100 is small and will not have a major impact on the global climate. On a regional scale, ocean bottom warming over the next 100 years will result in a relatively large decrease in the methane hydrate deposits, with the Arctic and Blake Ridge region, offshore South Carolina, being most affected."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on July 11, 2015, 01:12:23 PM
The linked article illustrates the value that social scientists bring to the table for critiquing potential approaches to addressing our current anthropogenic driven situation:

Frank W. Geels, Andy McMeekin, Josephine Mylan & Dale Southerton (September 2015), "A critical appraisal of Sustainable Consumption and Production research: The reformist, revolutionary and reconfiguration positions", Global Environmental Change, Volume 34, Pages 1–12, doi:10.1016/j.gloenvcha.2015.04.013

http://www.sciencedirect.com/science/article/pii/S0959378015000813 (http://www.sciencedirect.com/science/article/pii/S0959378015000813)

http://ac.els-cdn.com/S0959378015000813/1-s2.0-S0959378015000813-main.pdf?_tid=6ca2c534-27bb-11e5-b0b8-00000aacb362&acdnat=1436612344_fec7fe12dfeb222fdbb8ec7165ba3f63 (http://ac.els-cdn.com/S0959378015000813/1-s2.0-S0959378015000813-main.pdf?_tid=6ca2c534-27bb-11e5-b0b8-00000aacb362&acdnat=1436612344_fec7fe12dfeb222fdbb8ec7165ba3f63)

Abstract: "This conceptual review article provides a critical appraisal of Sustainable Consumption and Production research, which is currently framed by two generic positions. First, the ‘reformist’ position, which focuses on firms pursuing green eco-innovations and consumers buying eco-efficient products, represents the political and academic orthodoxy. Second, the ‘revolutionary’ position, which is a radical critique of the mainstream, advocates the abolishment of capitalism, materialism, and consumerism, and promotes values such as frugality, sufficiency, and localism. We find this dichotomous debate problematic, because it is intellectually stifling and politically conservative (in its outcomes). To move beyond this dichotomy, we propose a third position, ‘reconfiguration’, which focuses on transitions in socio-technical systems and daily life practices and accommodates new conceptual frameworks. For each of the three positions, we discuss: (1) the scale and type of change, (2) views on consumption and production in exemplary approaches, (3) underlying theoretical, epistemological and normative orientations, (4) policy implications, and (5) critical appraisal. The conclusion compares the three positions, provides arguments for the fruitfulness of the reconfiguration-position and offers four critical reflections about future Sustainable Consumption and Production research agendas."

Extract: "The reconfiguration position accords with Urry’s (2010) call for social scientists to articulate a middle way between approaches that focus either on macro-contexts (the nature of capitalism, nature-society interactions, modernity) or on individuals (choices, attitudes, motivations). Instead, Urry (2010) suggests that that a sociology of climate change (and sustainable consumption and production more broadly) ‘‘is not a question of changing what individuals do or do not do but changing whole systems of economic, technological and social practice. Systems are crucial here and not individual behaviour’’ (Urry, 2010). In line with this call, the reconfiguration position argues that SCP-research and policy should focus on the transformation of socio-technical systems and daily life practices in domains such as mobility, food, and energy provision and use (Shove, 2003; Elzen et al., 2004; Tukker et al., 2007). This unit of analysis is important, because mobility (automobile and air transport), food (meat and dairy), and domestic energy consumption (heating/cooling, lighting, washing, showering, appliances) account for 70–80% of lifecycle impacts in industrialized countries (Tukker et al., 2010)."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on July 11, 2015, 01:31:21 PM
The linked article applies systems analysis using historical elasticities to estimate what life expectancies, & life styles, that can be achieved in Africa, Centrally Planned Asia & South Asia; while remaining within the AR5 stated carbon budgets (which probably err on the side of reduced public safety):

William F. Lamb & Narasimha D. Rao (July 2015), "Human development in a climate-constrained world: What the past says about the future", Global Environmental Change, Volume 33, Pages 14–22, doi:10.1016/j.gloenvcha.2015.03.010


http://www.sciencedirect.com/science/article/pii/S0959378015000473 (http://www.sciencedirect.com/science/article/pii/S0959378015000473)


Abstract: "Energy consumption is necessary for the delivery of human development by supporting access to basic needs, services and infrastructure. Given prevailing technologies and the high degree of inertia in practical rates of decarbonisation, growth in energy consumption from rising global living standards may drive consequent greenhouse gas emissions (GHG). In this paper the ‘development as usual’ GHG emissions impact of achieving high levels of life expectancy, access to basic needs and continued economic growth are projected to the mid-century using historical elasticities of development and energy consumption in 3 regions – Africa, Centrally Planned Asia, and South Asia. The results suggest that long life expectancy and high levels of access to basic needs are achievable at lower levels of emissions than continued economic growth, but will consume a substantial share of the global budget associated with a 2 °C climate goal."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on July 11, 2015, 01:50:04 PM
The linked article discusses extending the Shared Socioeconomic Pathways (SSPs) for sub-national impacts, adaption and vulnerability studies:

Syeda Mariya Absar & Benjamin L. Preston (July 2015), "Extending the Shared Socioeconomic Pathways for sub-national impacts, adaptation, and vulnerability studies", Global Environmental Change, Volume 33, Pages 83–96, doi:10.1016/j.gloenvcha.2015.04.004

http://www.sciencedirect.com/science/article/pii/S0959378015000564 (http://www.sciencedirect.com/science/article/pii/S0959378015000564)

Abstract: "The exploration of alternative socioeconomic futures is an important aspect of understanding the potential consequences of climate change. While socioeconomic scenarios are common and, at times essential, tools for the impacts, adaptation and vulnerability and integrated assessment modeling research communities, their approaches to scenario development have historically been quite distinct. However, increasing convergence of impacts, adaptation and vulnerability and integrated assessment modeling research in terms of scales of analysis suggests there may be value in the development of a common framework for socioeconomic scenarios. The Shared Socioeconomic Pathways represents an opportunity for the development of such a common framework. However, the scales at which these global storylines have been developed are largely incommensurate with the sub-national scales at which impacts, adaptation and vulnerability and, increasingly, integrated assessment modeling studies are conducted. The objective of this study was to develop sub-national and sectoral extensions of the global SSP storylines in order to identify future socioeconomic challenges for adaptation for the U.S. Southeast. A set of nested qualitative socioeconomic storyline elements, integrated storylines, and accompanying quantitative indicators were developed through an application of the Factor–Actor–Sector framework. In addition to revealing challenges and opportunities associated with the use of the SSPs as a basis for more refined scenario development, this study generated sub-national storyline elements and storylines that can subsequently be used to explore the implications of alternative sub-national socioeconomic futures for the assessment of climate change impacts and adaptation."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on July 11, 2015, 02:01:00 PM
The linked article uses systems analysis to discuss how difficult, and how important, it is to reduce the contributions of non-carbon dioxide gases to achieving deep mitigation scenarios:

David E.H.J. Gernaat, Katherine Calvin, Paul L. Lucas, Gunnar Luderer, Sander A.C. Otto, Shilpa Rao, Jessica Strefler & Detlef P. van Vuuren (July 2015), "Understanding the contribution of non-carbon dioxide gases in deep mitigation scenarios", Global Environmental Change, Volume 33, Pages 142–153, doi:10.1016/j.gloenvcha.2015.04.010


http://www.sciencedirect.com/science/article/pii/S0959378015000709 (http://www.sciencedirect.com/science/article/pii/S0959378015000709)

Abstract: "In 2010, the combined emissions of methane (CH4), nitrous oxide (N2O) and the fluorinated gasses (F-gas) accounted for 20–30% of Kyoto emissions and about 30% of radiative forcing. Current scenario studies conclude that in order to reach deep climate targets (radiative forcing of 2.8 W/m2) in 2100, carbon dioxide (CO2) emissions will need to be reduced to zero or negative. However, studies indicated that non-CO2 emissions seem to be have less mitigation potential. To support effective climate policy strategies, an in-depth assessment was made of non-CO2 greenhouse gas emission and their sources in achieving an ambitious climate target. Emission scenarios were assessed that had been produced by six integrated assessments models, which contributed to the scenario database for the fifth IPCC report. All model scenarios reduced emissions from energy-related sectors, largely resulting from structural changes and end-of-pipe abatement technologies. However, emission reductions were much less in the agricultural sectors. Furthermore, there were considerable differences in abatement potential between the model scenarios, and most notably in the agricultural sectors. The paper shows that better exploration of long-term abatement potential of non-CO2 emissions is critical for the feasibility of deep climate targets."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on July 11, 2015, 02:21:03 PM
The linked open access reference uses systems analysis to discuss potentially more effective pathways to help conserve biodiversity through 2020:

R. Hill, G.A. Dyer, L.-M. Lozada-Ellison, A. Gimona, J. Martin-Ortega, J. Munoz-Rojas & I.J. Gordon (September 2015), "A social–ecological systems analysis of impediments to delivery of the Aichi 2020 Targets and potentially more effective pathways to the conservation of biodiversity", Global Environmental Change, Volume 34, Pages 22–34, doi:10.1016/j.gloenvcha.2015.04.005


http://www.sciencedirect.com/science/article/pii/S0959378015000576 (http://www.sciencedirect.com/science/article/pii/S0959378015000576)

http://ac.els-cdn.com/S0959378015000576/1-s2.0-S0959378015000576-main.pdf?_tid=f0f837e2-27c5-11e5-be84-00000aacb35e&acdnat=1436616861_407c9f5f9a39ca46c19c0fb21f79cc33 (http://ac.els-cdn.com/S0959378015000576/1-s2.0-S0959378015000576-main.pdf?_tid=f0f837e2-27c5-11e5-be84-00000aacb35e&acdnat=1436616861_407c9f5f9a39ca46c19c0fb21f79cc33)

Abstract: "The Aichi 2020 Targets, under the Convention on Biological Diversity (CBD), aim to halt the loss of biodiversity by 2020, in order to ensure that ecosystems continue to provide essential services. Here we apply a social–ecological systems analysis to provide insight into the diverse system interactions that pose impediments to delivery of the Aichi Targets. We applied an analytical framework of pair-wise exchanges along six axes between the social, economic, environmental and political loci of the global social–ecological system. The analysis identified that many impediments result from partial decoupling in the system through phenomena including delayed feedbacks and insufficient information flows. It suggests 15 of the Aichi Targets are unlikely to be delivered; 3 are likely to be delivered in part; and 2 in full. We considered how interventions at leverage points may overcome the impediments, and compared these to actions included within the Implementation Decision for the Aichi Targets, to find gaps. These new leverage points to fill identified gaps involve many aspects of system re-coupling: co-production of knowledge and more equitable food systems governance (environmental–social axis); support for social change movements (social–political axis); an appropriate financial target for biodiversity conservation investment, with a clear means of implementation such as a currency transaction tax (economic–political axis); and co-governance of natural resources (environmental–political axis). The recently released Global Biodiversity Outlook 4 shows that 18 of the 20 Aichi Targets are tracking in accordance with our analysis; and that current efforts are unlikely to result in an improvement in the base state of biodiversity by 2020, confirming some of our results. We argue that attention to the interactions within, and the partial decoupling of, the global social–ecological system provides new insights, and is worthy of further attention both for delivery of the Aichi Targets and for guiding longer term actions for the conservation of biodiversity."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on July 11, 2015, 11:09:34 PM
The linked open access reference uses systems analysis to discuss potentially more effective pathways to help conserve biodiversity through 2020:

R. Hill, G.A. Dyer, L.-M. Lozada-Ellison, A. Gimona, J. Martin-Ortega, J. Munoz-Rojas & I.J. Gordon (September 2015), "A social–ecological systems analysis of impediments to delivery of the Aichi 2020 Targets and potentially more effective pathways to the conservation of biodiversity", Global Environmental Change, Volume 34, Pages 22–34, doi:10.1016/j.gloenvcha.2015.04.005


http://www.sciencedirect.com/science/article/pii/S0959378015000576 (http://www.sciencedirect.com/science/article/pii/S0959378015000576)

http://ac.els-cdn.com/S0959378015000576/1-s2.0-S0959378015000576-main.pdf?_tid=f0f837e2-27c5-11e5-be84-00000aacb35e&acdnat=1436616861_407c9f5f9a39ca46c19c0fb21f79cc33 (http://ac.els-cdn.com/S0959378015000576/1-s2.0-S0959378015000576-main.pdf?_tid=f0f837e2-27c5-11e5-be84-00000aacb35e&acdnat=1436616861_407c9f5f9a39ca46c19c0fb21f79cc33)

Abstract: "The Aichi 2020 Targets, under the Convention on Biological Diversity (CBD), aim to halt the loss of biodiversity by 2020, in order to ensure that ecosystems continue to provide essential services. Here we apply a social–ecological systems analysis to provide insight into the diverse system interactions that pose impediments to delivery of the Aichi Targets. We applied an analytical framework of pair-wise exchanges along six axes between the social, economic, environmental and political loci of the global social–ecological system. The analysis identified that many impediments result from partial decoupling in the system through phenomena including delayed feedbacks and insufficient information flows. It suggests 15 of the Aichi Targets are unlikely to be delivered; 3 are likely to be delivered in part; and 2 in full. We considered how interventions at leverage points may overcome the impediments, and compared these to actions included within the Implementation Decision for the Aichi Targets, to find gaps. These new leverage points to fill identified gaps involve many aspects of system re-coupling: co-production of knowledge and more equitable food systems governance (environmental–social axis); support for social change movements (social–political axis); an appropriate financial target for biodiversity conservation investment, with a clear means of implementation such as a currency transaction tax (economic–political axis); and co-governance of natural resources (environmental–political axis). The recently released Global Biodiversity Outlook 4 shows that 18 of the 20 Aichi Targets are tracking in accordance with our analysis; and that current efforts are unlikely to result in an improvement in the base state of biodiversity by 2020, confirming some of our results. We argue that attention to the interactions within, and the partial decoupling of, the global social–ecological system provides new insights, and is worthy of further attention both for delivery of the Aichi Targets and for guiding longer term actions for the conservation of biodiversity."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on July 13, 2015, 06:23:47 PM
The linked article discusses the interdisciplinary role that all the different sciences will have in modeling the Anthropocene (see the attached associated image):

Matthew Nisbet (2015), "In the Anthropocene, Every Discipline Has a Role"


http://www.socialsciencespace.com/2015/01/in-the-anthropocene-every-discipline-has-a-role/ (http://www.socialsciencespace.com/2015/01/in-the-anthropocene-every-discipline-has-a-role/)

Extract: "In charting a hopeful path forward in the Anthropocene, universities and colleges will play a central role by sponsoring interdisciplinary courses, degree programs and related initiatives."

Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on July 17, 2015, 10:01:48 PM
The linked reference (with an open access pdf) discusses the very significant limitations of current integrated assessment model (IAM) projections.  Indeed, the paper indicates that we do not even know whether some kinds of mitigating efforts will result in positive or negative impacts on climate change.  The paper concludes that even in the face of such large uncertainties about IAM projections; nevertheless, policy makers should try to fight climate change as efficiently and effectively as possible (however, I suspect that denialists will likely twist the findings of the paper to conclude that the uncertainties are too high to take effective action, so we should do nothing):

Richard A. Rosen, Author Vitae & Edeltraud Guenther (February 2015), "The economics of mitigating climate change: What can we know?", Technological Forecasting and Social Change, Volume 91, Pages 93–106, doi:10.1016/j.techfore.2014.01.013


http://www.sciencedirect.com/science/article/pii/S0040162514000468 (http://www.sciencedirect.com/science/article/pii/S0040162514000468)

Abstract: "The long-term economics of mitigating climate change over the long run has played a high profile role in the most important analyses of climate change in the last decade, namely the Stern Report and the IPCC's Fourth Assessment. However, the various kinds of uncertainties that affect these economic results raise serious questions about whether or not the net costs and benefits of mitigating climate change over periods as long as 50 to 100 years can be known to such a level of accuracy that they should be reported to policymakers and the public. This paper provides a detailed analysis of the derivation of these estimates of the long-term economic costs and benefits of mitigation. It particularly focuses on the role of technological change, especially for energy efficiency technologies, in making the net economic results of mitigating climate change unknowable over the long run.
Because of these serious technical problems, policymakers should not base climate change mitigation policy on the estimated net economic impacts computed by integrated assessment models. Rather, mitigation policies must be forcefully implemented anyway given the actual physical climate change crisis, in spite of the many uncertainties involved in trying to predict the net economics of doing so."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on July 17, 2015, 10:08:47 PM
The linked reference (with an open access pdf) examines many of the uncertainties associated with modeling the economic impacts of climate change on agriculture.  For example the paper identifies that differences in local (smaller spatial scales) agricultural practices can complicate policies to promote food production and that research on how to adapt agriculture to climate change impacts (say by improving food storage systems) is limited funding restrictions:

Francisco J. Fernández and Maria Blanco (2015), "Modelling the Economic Impacts of Climate Change on Global and European Agriculture. Review of Economic Structural Approaches", Economics: The Open-Access, Open-Assessment E-Journal, 9 (2015-10): 1—53. http://dx.doi.org/10.5018/economics-ejournal.ja.2015-10 (http://dx.doi.org/10.5018/economics-ejournal.ja.2015-10)

http://www.economics-ejournal.org/economics/journalarticles/2015-10 (http://www.economics-ejournal.org/economics/journalarticles/2015-10)

Abstract: "The economic effects of climate change on agriculture have been widely assessed in the last two decades. Many of these assessments are based on the integration of biophysical and agro-economic models, allowing to understand the physical and socio-economic responses of the agricultural sector to future climate change scenarios. The evolution of the bio-economic approach has gone through different stages. This review analyses its evolution: firstly, framing the bio-economic approach into the context of the assessments of climate change impacts, and secondly, by reviewing empirical studies at the global and European level. Based on this review, common findings emerge in both global and regional assessments. Among them, the authors show that overall results tend to hide significant disparities on smaller spatial scales. Furthermore, due to the effects of crop prices over yield changes, several authors highlight the need to consider endogenous price models to assess production impacts of climate change. Further, major developments are discussed: the progress made since the last two decades and the recent methods used to provide insights into modeling uncertainties. However, there are still challenges to be met. On this matter, the authors take these unresolved challenges as guidelines for future research."

Extract: "Finally, another important issue encompassed by the structural approach and their methods is the assessment of climate change adaptations. One particular dimension of the adaptation question is related to adaptation policies. Several studies have assessed the effects of trade liberalisation as a tool for adapting to climate change (e.g., Randhir and Hertel, 2000). However, it is still necessary to assess a wider range of adaptation policies in modelling frameworks (Easterling et al., 2007). An interesting aim of future research could be to determine the effects of adaptation policies that increase public spending on research and technology. On-going efforts in this direction have been reported in Ignaciuk and Mason-D’Croz (2014). By contrast, several potential adaptation options extend beyond in food production adaptations. For instance, storage policies have not been analysed although they largely influence food prices."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on July 17, 2015, 10:15:47 PM
It is my belief that the socio-economic systems in the Pakistan-Northern India- Bangladesh area (characterized by the Gange-Brahmaputra-Meghna (GBM) river basins, which holds over 650 million people, see attached map) is particularly sensitive to climate change impacts (such as heatwaves, droughts, floods, and changes in the monsoon behavior).  In this regards the linked reference highlights the socio-economic impacts of the flow rates and water quality of the GBM river systems, and concludes that this impacts are large:

P. G. Whitehead,   E. Barbour,   M. N. Futter,   S. Sarkar,   H. Rodda,   J. Caesar,  D. Butterfield,   L. Jin,   R. Sinha,   R. Nicholls and   M. Salehin  (2015) "Impacts of climate change and socio-economic scenarios on flow and water quality of the Ganges, Brahmaputra and Meghna (GBM) river systems: low flow and flood statistics", Environ. Sci.: Processes Impacts, 17, 1057-1069, DOI: 10.1039/C4EM00619D


http://pubs.rsc.org/en/Content/ArticleLanding/2015/EM/C4EM00619D# (http://pubs.rsc.org/en/Content/ArticleLanding/2015/EM/C4EM00619D#)!divAbstract

Abstract: "The potential impacts of climate change and socio-economic change on flow and water quality in rivers worldwide is a key area of interest. The Ganges–Brahmaputra–Meghna (GBM) is one of the largest river basins in the world serving a population of over 650 million, and is of vital concern to India and Bangladesh as it provides fresh water for people, agriculture, industry, conservation and for the delta system downstream. This paper seeks to assess future changes in flow and water quality utilising a modelling approach as a means of assessment in a very complex system. The INCA-N model has been applied to the Ganges, Brahmaputra and Meghna river systems to simulate flow and water quality along the rivers under a range of future climate conditions. Three model realisations of the Met Office Hadley Centre global and regional climate models were selected from 17 perturbed model runs to evaluate a range of potential futures in climate. In addition, the models have also been evaluated using socio-economic scenarios, comprising (1) a business as usual future, (2) a more sustainable future, and (3) a less sustainable future. Model results for the 2050s and the 2090s indicate a significant increase in monsoon flows under the future climates, with enhanced flood potential. Low flows are predicted to fall with extended drought periods, which could have impacts on water and sediment supply, irrigated agriculture and saline intrusion. In contrast, the socio-economic changes had relatively little impact on flows, except under the low flow regimes where increased irrigation could further reduce water availability. However, should large scale water transfers upstream of Bangladesh be constructed, these have the potential to reduce flows and divert water away from the delta region depending on the volume and timing of the transfers. This could have significant implications for the delta in terms of saline intrusion, water supply, agriculture and maintaining crucial ecosystems such as the mangrove forests, with serious implications for people's livelihoods in the area. The socio-economic scenarios have a significant impact on water quality, altering nutrient fluxes being transported into the delta region."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on July 22, 2015, 04:39:43 PM
The linked Nature article emphasizes that farmer's focus on near-term profit/survivability; and that if our food supply is to become climate proofed then planners will need to model environmental and socio-economic conditions several decades in the future so that we can move in a more thought manner into an uncertain future:

http://www.nature.com/news/quest-for-climate-proof-farms-1.18015 (http://www.nature.com/news/quest-for-climate-proof-farms-1.18015)

Extract: "“It is utterly important that planners in each region and each locality will have all the knowledge in place that they need,” she says. “There are no dumb farmers, but farmers focus on present realities. We must leave no stone unturned to help them plan for a hotter future.”"
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on August 05, 2015, 06:22:40 PM
The linked reference points out that a holistic approach to modeling & planning will be needed to address future food security requirements, for feed a growing world population (see attached image):

Paul R. Ehrlich & John Harte (July 2015), "Food security requires a new revolution", International Journal of Environmental Studies, DOI:10.1080/00207233.2015.1067468


http://www.tandfonline.com/doi/abs/10.1080/00207233.2015.1067468#.VcI1jqPn_mR (http://www.tandfonline.com/doi/abs/10.1080/00207233.2015.1067468#.VcI1jqPn_mR)


Abstract: "A central responsibility of societies should be supplying adequate nourishment to all. For roughly a third of the global human population, that goal is not met today. More ominously, that population is projected to increase some 30% by 2050. The intertwined natural and social systems, that must meet the challenge of producing and equitably distributing much more food without wrecking humanity’s life-support systems, face a daunting array of challenges and uncertainties. These have roots in the agricultural revolution that transformed our species and created civilization. Profound and multifaceted changes, revising closely-held cultural traditions and penetrating most of civilization will be required, if an unprecedented famine is to be avoided."

http://www.environmentalhealthnews.org/ehs/news/2015/aug/food-security-planet-planetary-boundaries-climate-change-agriculture-farming-organic-solutions-revolution (http://www.environmentalhealthnews.org/ehs/news/2015/aug/food-security-planet-planetary-boundaries-climate-change-agriculture-farming-organic-solutions-revolution)

Extract: "“Some people say the whole problem is too many people and other people say it’s misdistribution of the crops we grow,” Ehrlich said in an interview. “They’re both right but this can’t be fixed by dealing with only one end of the problem.”
Scientists for too long have been looking at how to feed the world in “fragments,” Ehrlich said.
“Some look at solving food problems with crops grown in higher temperatures; some look at reducing waste,” he said. “It’s crystal clear that none of the things that need to be done are being done on a scale that would be helpful.”
It’s not just about pumping out more crops or reducing the amount of people. “Planning for a sustainable and effective food production system will surely require heeding constraints from nature,” Ehrlich and Harte wrote.
They argue that economic equality, population growth and environmental health are all linked. Governments must address the whole system to avoid future famine."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on August 08, 2015, 08:06:53 PM
The linked reference highlights the challenges of the Anthropocene on the biosphere:

Mark Williams, Jan Zalasiewicz, PK Haff, Christian Schwägerl, Anthony D Barnosky & Erle C Ellis (June 18, 2015), "The Anthropocene biosphere", The Anthropocene Review, doi: 10.1177/2053019615591020

http://anr.sagepub.com/content/early/2015/06/17/2053019615591020.abstract (http://anr.sagepub.com/content/early/2015/06/17/2053019615591020.abstract)

Abstract: "The geological record preserves evidence for two fundamental stages in the evolution of Earth’s biosphere, a microbial stage from ~3.5 to 0.65 Ga, and a metazoan stage evident by c. 650 Ma. We suggest that the modern biosphere differs significantly from these previous stages and shows early signs of a new, third stage of biosphere evolution characterised by: (1) global homogenisation of flora and fauna; (2) a single species (Homo sapiens) commandeering 25–40% of net primary production and also mining fossil net primary production (fossil fuels) to break through the photosynthetic energy barrier; (3) human-directed evolution of other species; and (4) increasing interaction of the biosphere with the technosphere (the global emergent system that includes humans, technological artefacts, and associated social and technological networks). These unique features of today’s biosphere may herald a new era in the planet’s history that could persist over geological timescales."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on September 03, 2015, 04:07:42 PM
The linked document from the Institute for Policy Studies, IPS, clearly demonstrates how bonus plans for fossil fuel executives encourages them to accelerate climate change.  If this is so easy to document, why don't any of the IPCC forcing scenarios consider this positive feedback mechanism (is it because the IPCC process is biased)?

http://www.ips-dc.org/executive-excess-2015/ (http://www.ips-dc.org/executive-excess-2015/)
http://www.ips-dc.org/wp-content/uploads/2015/09/EE2015-Money-To-Burn-Upd.pdf (http://www.ips-dc.org/wp-content/uploads/2015/09/EE2015-Money-To-Burn-Upd.pdf)


Extract: "This report reveals how our CEO pay system rewards executives for deepening the global climate crisis, based on in-depth analysis of the 30 largest publicly held U.S. oil, gas, and coal companies."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on September 14, 2015, 08:19:26 PM
The linked document (with an open access pdf) proposes to define the beginning of the Anthropocene by the on-set of simulated climate extremes and the attached image provides simulated output that if this criteria were to be adopted then the early 1980's might be a candidate for defining the beginning of the Anthropocene:

Andrew D King, Markus G Donat, Erich M Fischer, Ed Hawkins, Lisa V Alexander, David J Karoly, Andrea J Dittus, Sophie C Lewis and Sarah E Perkins (10 September 2015), "The timing of anthropogenic emergence in simulated climate extremes", Environmental Research Letters, Volume 10, Number 9


http://iopscience.iop.org/article/10.1088/1748-9326/10/9/094015/meta (http://iopscience.iop.org/article/10.1088/1748-9326/10/9/094015/meta)

Abstract: "Determining the time of emergence of climates altered from their natural state by anthropogenic influences can help inform the development of adaptation and mitigation strategies to climate change. Previous studies have examined the time of emergence of climate averages. However, at the global scale, the emergence of changes in extreme events, which have the greatest societal impacts, has not been investigated before. Based on state-of-the-art climate models, we show that temperature extremes generally emerge slightly later from their quasi-natural climate state than seasonal means, due to greater variability in extremes. Nevertheless, according to model evidence, both hot and cold extremes have already emerged across many areas. Remarkably, even precipitation extremes that have very large variability are projected to emerge in the coming decades in Northern Hemisphere winters associated with a wettening trend. Based on our findings we expect local temperature and precipitation extremes to already differ significantly from their previous quasi-natural state at many locations or to do so in the near future. Our findings have implications for climate impacts and detection and attribution studies assessing observed changes in regional climate extremes by showing whether they will likely find a fingerprint of anthropogenic climate change."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on September 16, 2015, 04:27:35 PM
To add to my thoughts on my immediate prior post about King et al. (2015):

The acceleration of extreme weather events beginning in the early 1980's may be partially linked to the US Clean Air Act which reduced the negative forcing associate with US aerosols; possibly working synergistically with the positive phase of the PDO cycle (beginning at that time) and possibly the 82-83 Super El Nino event as a trigger.
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on October 30, 2015, 11:10:07 PM
Integrated assessment models, or IAMs, have historically been very poor at including non-linear effects in their projections, so in the past they projected only minor climate change impacts on wealthy countries.  However, the first linked reference, Burke et al. (2015), shows that when non-linear effects are included in macro assessments even rich countries suffer from climate change; while the second linked Vox article indicates the uncertainty loop (shown in the first image) and the risks from "fat-tailed" climate sensitivity pdfs; which could make the impacts of climate change to be far worse that that indicated by Burke et al. (2015):

Marshall Burke, Solomon M. Hsiang & Edward Miguel (2015), "Global non-linear effect of temperature on economic production", Nature, doi:10.1038/nature15725


http://www.nature.com/nature/journal/vaop/ncurrent/full/nature15725.html#ref5 (http://www.nature.com/nature/journal/vaop/ncurrent/full/nature15725.html#ref5)


Abstract: "Growing evidence demonstrates that climatic conditions can have a profound impact on the functioning of modern human societies, but effects on economic activity appear inconsistent. Fundamental productive elements of modern economies, such as workers and crops, exhibit highly non-linear responses to local temperature even in wealthy countries. In contrast, aggregate macroeconomic productivity of entire wealthy countries is reported not to respond to temperature, while poor countries respond only linearly. Resolving this conflict between micro and macro observations is critical to understanding the role of wealth in coupled human–natural systems and to anticipating the global impact of climate change. Here we unify these seemingly contradictory results by accounting for non-linearity at the macro scale. We show that overall economic productivity is non-linear in temperature for all countries, with productivity peaking at an annual average temperature of 13 °C and declining strongly at higher temperatures. The relationship is globally generalizable, unchanged since 1960, and apparent for agricultural and non-agricultural activity in both rich and poor countries. These results provide the first evidence that economic activity in all regions is coupled to the global climate and establish a new empirical foundation for modelling economic loss in response to climate change, with important implications. If future adaptation mimics past adaptation, unmitigated warming is expected to reshape the global economy by reducing average global incomes roughly 23% by 2100 and widening global income inequality, relative to scenarios without climate change. In contrast to prior estimates, expected global losses are approximately linear in global mean temperature, with median losses many times larger than leading models indicate."

http://www.vox.com/2015/10/23/9604120/climate-models-uncertainty (http://www.vox.com/2015/10/23/9604120/climate-models-uncertainty)
Extract: "For most variables, model uncertainty represents less than a quarter of overall uncertainty. Most of the uncertainty in IAMs is parametric uncertainty. (The only variable for which model uncertainty is the majority is the social cost of carbon, probably because it's powerfully affected by choice of discount rate.)
The authors conclude that "relying upon ensembles as a technique for determining the uncertainty of future outcomes is (at least for the major climate change variables) highly deficient. Ensemble uncertainty tends to underestimate overall uncertainty by a significant amount."


The point about "catastrophic climate outcomes" is important, and the basis for another common critique of IAMs. The charge is that IAMs can only model continuous damage functions — that is, damages that rise smoothly and continuously. They are incapable of dealing with discontinuities, with sudden, nonlinear changes. These are the "tipping points" people are always worrying about, wherein some natural or social system, subjected to continuous stress, experiences a rapid, lurching phase shift to a different state. Some argue that cost-benefit analysis — of which IAMs are an elaborate form — are intrinsically incapable of dealing with such catastrophes.

A Harvard climate economist named Martin Weitzman has, for several years now, been mounting a counterargument to the use of IAMs (and conventional cost-benefit generally) to assess climate policy. The best expression of the argument remains his influential 2009 paper "On Modeling and Interpreting the Economics of Catastrophic Climate Change." (See also last year's "Fat Tails and the Social Cost of Carbon" and his new book with economist Gernot Wagner, Climate Shock.)
In a nutshell, Weitzman argues that climate risks have "fat tail" distributions. In a normal bell-shaped probability curve, the sides drop off quickly — the risks of more extreme outcomes (the tails on either end) fall quickly to zero. But in a fat-tail distribution, risks fall off more slowly at the tails. There are small but non-negligible risks of very extreme outcomes."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on November 05, 2015, 12:14:53 AM
Per the linked reference, theory and experiments indicate that if scientists were able/willing to identify an upcoming tipping point with catastrophic damage [such as that identified by Hansen et al. (2015)] that this would simplify collective action to control GHG emissions.  Unfortunately, the research also indicates that the higher degree of strategic reasoning used by current policy elites increase the risk for climate catastrophe:

Vilhelm Verendel, Daniel J. A. Johansson & Kristian Lindgren (2015), "Strategic reasoning and bargaining in catastrophic climate change games", Nature Climate Change, doi:10.1038/nclimate2849

http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2849.html (http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2849.html)


Abstract: "Two decades of international negotiations show that agreeing on emission levels for climate change mitigation is a hard challenge. However, if early warning signals were to show an upcoming tipping point with catastrophic damage, theory and experiments suggest this could simplify collective action to reduce greenhouse gas emissions. At the actual threshold, no country would have a free-ride incentive to increase emissions over the tipping point, but it remains for countries to negotiate their emission levels to reach these agreements. We model agents bargaining for emission levels using strategic reasoning to predict emission bids by others and ask how this affects the possibility of reaching agreements that avoid catastrophic damage. It is known that policy elites often use a higher degree of strategic reasoning, and in our model this increases the risk for climate catastrophe. Moreover, some forms of higher strategic reasoning make agreements to reduce greenhouse gases unstable. We use empirically informed levels of strategic reasoning when simulating the model."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on November 05, 2015, 04:49:03 PM
As a follow-up to my last post about "Strategic reasoning and bargaining in catastrophic climate change games", I offer the following observations about the transition from the Kyoto Protocol to CoP21 coming to Paris:

1. After Kyoto the policy elite (in the developed world) found both that the developing world (including China) were all to willing to follow the developed world's fossil fuel path to prosperity; and that in the global capitalist market place nations (including Australia, Canada and Japan) decided that maintaining their market share was more important than the climate change risks indicated by science.

2. Following the Kyoto Protocol failure, the policy elite (the IPCC representatives from the developed world) decided to set the 2C limit high enough so that the developing countries (who want a 1.5C limit) would start to experience the pain of climate change damage, and thus would submit INDCs to CoP21; and so that the policy elite could wait to the last possible moment to offer any payment for "loss and damages" to the developing world caused by their past history of emissions.

3.  Unfortunately, the policy elite are assuming that even if they go past the 2C limit that future efforts (both emission limitations and geoengineering) will allow them to roll-back the worst impacts of climate change; however, in my opinion they very clearly misjudged the tipping point for abrupt ice mass loss from the WAIS, and also of the rate of acceleration of ESS with warming; which will likely nullify most of their future emissions and geoengineering efforts, resulting in a continuing acceleration of climate change damage.
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on November 05, 2015, 05:21:53 PM
To further expand on my last two posts, the linked SkS article for Nov. 5 2015, notes that 50-years ago today the US present Lyndon Johnson was adequately warned (in writing as verbally he was informed a year or two earlier) that following the emissions path that we have followed in the ensuing years would lead to the climate consequences that we are now experiencing, and that at this point geoengineering (the introduction of sulfates into the upper atmosphere) would be needed to limit those consequence.  This is a clear example of policy elite playing brinksmanship and relying on the optimistic assumption that geoengineering will save the world from the consequences of that brinksmanship; while in true all that they have really been doing is inviting global catastrophe (see attached image).

https://www.skepticalscience.com/scientists-warned-president-global-warming-50-years-ago-today.html (https://www.skepticalscience.com/scientists-warned-president-global-warming-50-years-ago-today.html)

Extract: "Fifty years ago today, as the American Association for the Advancement of Science highlighted, US president Lyndon Johnson’s science advisory committee sent him a report entitled Restoring the Quality of Our Environment. The introduction to the report noted:
Pollutants have altered on a global scale the carbon dioxide content of the air and the lead concentrations in ocean waters and human populations.
The report included a section on atmospheric carbon dioxide and climate change, written by prominent climate scientists Roger Revelle, Wallace Broecker, Charles Keeling, Harmon Craig, and J Smagorisnky. Reviewing the document today, one can’t help but be struck by how well these scientists understood the mechanisms of Earth’s climate change 50 years ago.
The report noted that within a few years, climate models would be able to reasonably project future global surface temperature changes. In 1974, one of its authors, Wallace Broecker did just that in a paper titled Climatic Change: Are We on the Brink of a Pronounced Global Warming?.



In addition to rising temperatures, the report discussed a variety of “other possible effects of an increase in atmospheric carbon dioxide”, including melting of the Antarctic ice cap, rise of sea level, warming of sea water, increased acidity of fresh waters (which also applies to the danger of ocean acidification, global warming’s evil twin), and an increase in plant photosynthesis.
These climate scientists warned President Johnson in 1965 not just of the dangers associated with human-caused global warming, but also that we might eventually have to consider geoengineering the climate to offset that warming and the risks that we’re causing by inadvertently running a dangerous experiment with the Earth’s climate."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on November 05, 2015, 05:38:13 PM
As a further following on my last three posts about modeling the consequences of the "higher level" of gamesmanship/brinksmanship that policy elite engage in, the linked Robert Scribbler article discusses the on-going witch hunt by US House Republicans who are targeting NOAA's most recent scientific findings (see the attached plot):

http://robertscribbler.com/2015/11/04/elephant-tears-over-lost-climate-cherries-house-republicans-most-recent-witch-hunt-targets-noaa/ (http://robertscribbler.com/2015/11/04/elephant-tears-over-lost-climate-cherries-house-republicans-most-recent-witch-hunt-targets-noaa/)

Extract: "Elephant Tears Over Lost Climate Cherries — House Republicans’ Most Recent Witch Hunt Targets NOAA

We live in dark times.
Dark times of rampant, media-supported climate change doubt and denial mongering. Dark times when global temperatures are hitting new all-time record highs and extreme weather and climate change related events are growing in scope, scale, and danger. Dark times when it is becoming all-too-obvious that the fossil fuel companies of the world are committed to continue burning their dangerous and heat amplifying fuels regardless of the cost or pain or devastation inflicted upon others. Inflicted on persons, communities and the very nations of this world. Dark times when public officials level unfounded and baseless attacks against the very science upon which we depend to track the dangerous and growing crisis that is human-forced warming of the globe.

House Republicans and the fossil fuel companies they serve are therefore complicit in a heinous act. And their actions over the past month in their leveling of trumped up charges against NOAA, is a stark proof for what they’re doing — committing themselves to inflicting climate atrocities upon the public for the benefit of fossil fuel companies which they represent."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on November 09, 2015, 10:22:15 PM
The linked (open access) reference studies the math of early warning signals of tipping points in periodically forced systems (like Earth Systems subject to climate change).  When they applied their process to Arctic sea ice they did not find any signs of local bifurcation; however, they also note that due to the particularly of Arctic sea ice one would not expect to find such a signal until just before it tips:

Williamson, M. S., Bathiany, S., and Lenton, T. M.: Early warning signals of tipping points in periodically forced systems, Earth Syst. Dynam. Discuss., 6, 2243-2272, doi:10.5194/esdd-6-2243-2015, 2015.


http://www.earth-syst-dynam-discuss.net/6/2243/2015/esdd-6-2243-2015.html (http://www.earth-syst-dynam-discuss.net/6/2243/2015/esdd-6-2243-2015.html)


Abstract. The prospect of finding generic early warning signals of an approaching tipping point in a complex system has generated much recent interest. Existing methods are predicated on a separation of timescales between the system studied and its forcing. However, many systems, including several candidate tipping elements in the climate system, are forced periodically at a timescale comparable to their internal dynamics. Here we find alternative early warning signals of tipping points due to local bifurcations in systems subjected to periodic forcing whose time scale is similar to the period of the forcing. These systems are not in, or close to, a fixed point. Instead their steady state is described by a periodic attractor. We show that the phase lag and amplification of the system response provide early warning signals, based on a linear dynamics approximation. Furthermore, the power spectrum of the system's time series reveals the generation of harmonics of the forcing period, the size of which are proportional to how nonlinear the system's response is becoming with nonlinear effects becoming more prominent closer to a bifurcation. We apply these indicators to a simple conceptual system and satellite observations of Arctic sea ice area, the latter conjectured to have a bifurcation type tipping point. We find no detectable signal of the Arctic sea ice approaching a local bifurcation.


 
Extract: "We did not find any detectable critical slowing down and therefore signs of this bifurcation. It should be noted however simple models of the sea ice suggest critical slowing down only occurs very close to the bifurcation making it very hard to detect."

Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on November 20, 2015, 08:24:18 PM
The linked (open access) reference uses a probabilistic analysis and findings that the low GHG emission scenarios are dependent upon both high carbon pricing and low renewable energy costs:

Jeremy Fyke and H Damon Matthews (16 November 2015), "A probabilistic analysis of cumulative carbon emissions and long-term planetary warming", Environmental Research Letters, Volume 10, Number 11, doi:10.1088/1748-9326/10/11/115007

http://iopscience.iop.org/article/10.1088/1748-9326/10/11/115007/meta (http://iopscience.iop.org/article/10.1088/1748-9326/10/11/115007/meta)


Abstract: "Efforts to mitigate and adapt to long-term climate change could benefit greatly from probabilistic estimates of cumulative carbon emissions due to fossil fuel burning and resulting CO2-induced planetary warming. Here we demonstrate the use of a reduced-form model to project these variables. We performed simulations using a large-ensemble framework with parametric uncertainty sampled to produce distributions of future cumulative emissions and consequent planetary warming. A hind-cast ensemble of simulations captured 1980–2012 historical CO2 emissions trends and an ensemble of future projection simulations generated a distribution of emission scenarios that qualitatively resembled the suite of Representative and Extended Concentration Pathways. The resulting cumulative carbon emission and temperature change distributions are characterized by 5–95th percentile ranges of 0.96–4.9 teratonnes C (Tt C) and 1.4 °C–8.5 °C, respectively, with 50th percentiles at 3.1 Tt C and 4.7 °C. Within the wide range of policy-related parameter combinations that produced these distributions, we found that low-emission simulations were characterized by both high carbon prices and low costs of non-fossil fuel energy sources, suggesting the importance of these two policy levers in particular for avoiding dangerous levels of climate warming. With this analysis we demonstrate a probabilistic approach to the challenge of identifying strategies for limiting cumulative carbon emissions and assessing likelihoods of surpassing dangerous temperature thresholds."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on January 15, 2016, 11:52:04 PM
The linked reference offer a game theory framework for better modeling human cooperation, which then could help to better model the Anthropocene:

Adam Bear and David G. Rand (January 11 2016), "Intuition, deliberation, and the evolution of cooperation", PNAS, doi: 10.1073/pnas.1517780113

http://www.pnas.org/content/early/2016/01/05/1517780113 (http://www.pnas.org/content/early/2016/01/05/1517780113)

Abstract: "Humans often cooperate with strangers, despite the costs involved. A long tradition of theoretical modeling has sought ultimate evolutionary explanations for this seemingly altruistic behavior. More recently, an entirely separate body of experimental work has begun to investigate cooperation’s proximate cognitive underpinnings using a dual-process framework: Is deliberative self-control necessary to reign in selfish impulses, or does self-interested deliberation restrain an intuitive desire to cooperate? Integrating these ultimate and proximate approaches, we introduce dual-process cognition into a formal game-theoretic model of the evolution of cooperation. Agents play prisoner’s dilemma games, some of which are one-shot and others of which involve reciprocity. They can either respond by using a generalized intuition, which is not sensitive to whether the game is one-shot or reciprocal, or pay a (stochastically varying) cost to deliberate and tailor their strategy to the type of game they are facing. We find that, depending on the level of reciprocity and assortment, selection favors one of two strategies: intuitive defectors who never deliberate, or dual-process agents who intuitively cooperate but sometimes use deliberation to defect in one-shot games. Critically, selection never favors agents who use deliberation to override selfish impulses: Deliberation only serves to undermine cooperation with strangers. Thus, by introducing a formal theoretical framework for exploring cooperation through a dual-process lens, we provide a clear answer regarding the role of deliberation in cooperation based on evolutionary modeling, help to organize a growing body of sometimes-conflicting empirical results, and shed light on the nature of human cognition and social decision making."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on January 16, 2016, 12:14:07 AM
The linked research indicates that observing weekly cycles of global fires can help separate natural from anthropogenic signals, thus allowing for improved modeling of the Anthropocene:

Nick Earl, Ian Simmonds & Nigel Tapper (2015): "Weekly cycles of global fires—Associations with religion, wealth and culture, and insights into anthropogenic influences on global climate" Geophysical Research Letters, DOI: 10.1002/2015GL066383


http://onlinelibrary.wiley.com/doi/10.1002/2015GL066383/full (http://onlinelibrary.wiley.com/doi/10.1002/2015GL066383/full)

Abstract: "One approach to quantifying anthropogenic influences on the environment and the consequences of those is to examine weekly cycles (WCs). No long-term natural process occurs on a WC so any such signal can be considered anthropogenic. There is much ongoing scientific debate as to whether regional-scale WCs exist above the statistical noise level, with most significant studies claiming that anthropogenic aerosols and their interaction with solar radiation and clouds (direct/indirect effect) is the controlling factor. A major source of anthropogenic aerosol, underrepresented in the literature, is active fire (AF) from anthropogenic burning for land clearance/management. WCs in AF have not been analyzed heretofore, and these can provide a mechanism for observed regional-scale WCs in several meteorological variables. We show that WCs in AFs are highly pronounced for many parts of the world, strongly influenced by the working week and particularly the day(s) of rest, associated with religious practices."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on January 16, 2016, 12:27:48 AM
The linked open access reference discusses a methodology based on the use of a KS-test that was used to determine the timing of the anthropogenic emergence in simulated climate extremes, and determines that the extreme event anthropogenic signal has already emerged.

Andrew D King, Markus G Donat, Erich M Fischer, Ed Hawkins, Lisa V Alexander, David J Karoly, Andrea J Dittus, Sophie C Lewis and Sarah E Perkins (10 September 2015) "The timing of anthropogenic emergence in simulated climate extremes", Environmental Research Letters, Volume 10, Number 9


http://iopscience.iop.org/article/10.1088/1748-9326/10/9/094015/meta (http://iopscience.iop.org/article/10.1088/1748-9326/10/9/094015/meta)

Abstract: "Determining the time of emergence of climates altered from their natural state by anthropogenic influences can help inform the development of adaptation and mitigation strategies to climate change. Previous studies have examined the time of emergence of climate averages. However, at the global scale, the emergence of changes in extreme events, which have the greatest societal impacts, has not been investigated before. Based on state-of-the-art climate models, we show that temperature extremes generally emerge slightly later from their quasi-natural climate state than seasonal means, due to greater variability in extremes. Nevertheless, according to model evidence, both hot and cold extremes have already emerged across many areas. Remarkably, even precipitation extremes that have very large variability are projected to emerge in the coming decades in Northern Hemisphere winters associated with a wettening trend. Based on our findings we expect local temperature and precipitation extremes to already differ significantly from their previous quasi-natural state at many locations or to do so in the near future. Our findings have implications for climate impacts and detection and attribution studies assessing observed changes in regional climate extremes by showing whether they will likely find a fingerprint of anthropogenic climate change."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on February 16, 2016, 05:50:07 PM
The linked reference looks at CMIP5 RCP 4.5 projection results to try to better understand the various mechanisms contributing to Arctic Amplification (AA):

Alexandre Laîné, Masakazu Yoshimori, and Ayako Abe-Ouchi (2016), "Surface Arctic Amplification Factors in CMIP5 Models: Land and Oceanic Surfaces, Seasonality", Journal of Climate, doi: http://dx.doi.org/10.1175/JCLI-D-15-0497.1 (http://dx.doi.org/10.1175/JCLI-D-15-0497.1)


http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-15-0497.1 (http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-15-0497.1)

Abstract: "Arctic Amplification (AA) is a major characteristic of observed global warming, yet the different mechanisms responsible for it and their quantification are still under investigation. In this study, we quantify the role of different factors contributing to local surface warming using the radiative kernel method applied at the surface, after 100 years of global warming under rcp4.5 scenario simulated by 32 climate models from the Coupled Model Intercomparison Project Phase 5. We investigate the warming factors and their seasonality for land and oceanic surfaces separately, and for different domains within each surface type where mechanisms differ.
Common factors contribute to both land and oceanic surface warming: tropospheric-mean atmospheric warming and greenhouse gas increases (mostly through water vapor feedback) for both tropical and Arctic regions, non-barotropic warming and surface warming sensitivity effects (negative in the tropics, positive in the Arctic), and warming cloud feedback in the Arctic in winter. Some mechanisms differ between land and oceanic surfaces: sensible and latent heat flux in the tropics, albedo feedback peaking at different times of the year in the Arctic due to different mean latitudes, a very large summer energy uptake and winter release by the Arctic Ocean, and a large evaporation enhancement in winter over the Arctic Ocean, whereas the peak occurs in summer over the ice-free Arctic land. The oceanic anomalous energy uptake/release is further studied, suggesting the primary role of seasonal variation of oceanic mixed layer temperature changes."
Title: Re: Modelling the Anthropocene
Post by: Sigmetnow on February 18, 2016, 04:29:15 PM
New Evidence Shows Global Climate Change Began Way Back in 1610
The impressively named Subcommission on Quaternary Stratigraphy of the International Union of Geological Sciences is a group that’s expected to decide later this year on whether the Anthropocene exists and when exactly it began. In anticipation, the Smithsonian’s Museum of Natural History in Washington, D.C., has prepared a new exhibit designed to highlight Earth’s new reality, placing human activity alongside triceratops fossils in a showcase of the planet’s 4.5-billion-year history.

Right now they’re leaning toward sometime around the year 1800—the beginning of the Industrial Revolution in Europe—but to declare a new geological epoch, scientists must find a “sufficiently large, clear and distinctive” transitional layer in rocks and sediments themselves. That’s tricky with the relatively slow growth of pollution that resulted from the Industrial Revolution: It took decades for the changes in atmospheric chemistry to be reflected in rock samples worldwide after coal burning began to take off. For this and other reasons, some argue that it’s hubris to suggest that humanity’s influence on the Earth will linger on for geologic timescales—that we’re more likely to be a blip in history, especially considering how hell-bent we seem to be toward self-destructive behavior.

On the other hand, others argue that we’ve already been shaping the planet on a vast scale for much longer. Last year, a controversial study identified a surprisingly early date—1610—as a possible start for the Anthropocene for a truly haunting reason: That’s roughly when depopulation of Native Americans began reached its peak after initial prolonged contact with European missionaries. Depending on how many people were already here before the Europeans arrived with their guns, germs, and steel, as many as 50 to 90 percent of Native Americans perished over a span of little more than 100 years—that’s tens of millions of people.

That paper, and others, assert that this happened so suddenly that a continent’s worth of forests regrew, shifting weather patterns and reducing global carbon dioxide levels to the point of possibly triggering the “Little Ice Age”—a period of cooler temperatures concentrated in Europe that began around 1550 and lasted for about 300 years, though other dates are also used to define it—not long after Europeans first arrived in 1492. The resulting decline in carbon dioxide from the regrowth of America’s forests was detectable as far away as ice cores in Antarctica.
http://www.slate.com/blogs/future_tense/2016/02/17/the_anthropocene_began_in_1610_with_the_little_ice_age.html (http://www.slate.com/blogs/future_tense/2016/02/17/the_anthropocene_began_in_1610_with_the_little_ice_age.html)
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on February 18, 2016, 05:39:34 PM
New Evidence Shows Global Climate Change Began Way Back in 1610

See also the information on the Early Anthropocene here:

http://forum.arctic-sea-ice.net/index.php/topic,852.0.html (http://forum.arctic-sea-ice.net/index.php/topic,852.0.html)
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on February 19, 2016, 05:55:24 PM
Now that scientists finally understand why people will willingly harm others when following orders (because they feel genuinely less responsible); theoretically the IPCC scientists who develop the radiative forcing scenarios will adjust their projections accordingly (under the assumption that they will not feel relieved of responsibility due to pressure from policymakers to continue developing Pollyanna projections):

Alison Abbott (18 February 2016), "Modern Milgram experiment sheds light on power of authority: People obeying commands feel less responsibility for their actions", Nature, doi:10.1038/nature.2016.19408

http://www.nature.com/news/modern-milgram-experiment-sheds-light-on-power-of-authority-1.19408 (http://www.nature.com/news/modern-milgram-experiment-sheds-light-on-power-of-authority-1.19408)

Extract: "More than 50 years after a controversial psychologist shocked the world with studies that revealed people’s willingness to harm others on order, a team of cognitive scientists has carried out an updated version of the iconic ‘Milgram experiments’.

Their findings may offer some explanation for Stanley Milgram's uncomfortable revelations: when following commands, they say, people genuinely feel less responsibility for their actions — whether they are told to do something evil or benign."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on February 20, 2016, 07:18:32 PM
As a follow-up to my last post, I re-post the following regarding how the RCP scenarios developed for AR5 intentionally and knowingly erred on the side of least drama (as compared to AR4 methodology):

The linked, open access, reference indicates that if the AR5 global mean surface temperature, GMST, projections had not adopted procedures (w.r.t. carbon cycles) that err on the side of least drama, they would have projected higher values of GMST, with wider ranges of uncertainty, as illustrated by the attached plot with the caption cited below:

Bodman, R. W., Rayner, P. J. and Jones, R. N. (2016), "How do carbon cycle uncertainties affect IPCC temperature projections?",  Atmosph. Sci. Lett., doi: 10.1002/asl.648

http://onlinelibrary.wiley.com/doi/10.1002/asl.648/abstract (http://onlinelibrary.wiley.com/doi/10.1002/asl.648/abstract)

Abstract: "Carbon cycle uncertainties associated with the Intergovernmental Panel on Climate Change temperature-change projections were treated differently between the Fourth and Fifth Assessment Reports as the latter focused on concentration- rather than emission-driven experiments. Carbon cycle feedbacks then relate to the emissions consistent with a particular concentration. A valuable alternative is to include all uncertainties in a single step from emissions to temperatures. We use a simple climate model with an observationally constrained parameter distribution to explore the carbon cycle and temperature-change projections, simulating the emission-driven Representative Concentration Pathways. The resulting range of uncertainty is a somewhat wider and asymmetric likely range (biased high)."

Caption: "Plume plots for ΔGMT change projections 2000–2100, ∘C relative to 1986–2005. MAGICC results with carbon cycle temperature feedbacks on (CC-on) and switched off (CC-off) (a) RCP2.6, (b) RCP4.5, (c) RCP6.0 and (d) RCP8.5. Shaded regions indicate the 67% confidence interval for CC-on (green) and CC-off (blue), with median results as solid green and dashed blue lines, respectively."

As one example of the ESLD approach used by the RCP developers, they assumed that regulators would improved control of anthropogenic methane leaks (as it only seemed like a rational thing to do); while in actuality anthropogenic methane leaks have been growing rapidly since the RCP scenarios were developed, and as the GWP10 for methane is 130 this fact has had a major impact of recent global warming, and has made scenarios like RCP 4.5 seem particularly Pollyannaish).

Edit: Note that I am restraining myself from pointing-out other ESLD assumptions such as using somewhat low (and linear) climate sensitivity values for calculating GMST changes for the various scenarios, as I find that when I talk about more than one thing at a time, very little of the message is conveyed, and I hope that when the preliminary ACME projections are published before AR6 that they adopted less Pollyannaish assumptions and reasonably account for the multiple non-linear feedback mechanisms).
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on February 22, 2016, 06:25:46 PM
The linked article indicates that not all CMIP5 model projections are equal and those that inhomogeneities in homogeneous greenhouse gas (HGG) perform better and that correctly account for such inhomogeneities can account for 90% of the variance in radiative forcing.  Hopefully, state-of-the-art ESMs (like ACME) will get this accounting correct:

Yi Huang, Xiaoxiao Tan & Yan Xia (18 February 2016), "Inhomogeneous radiative forcing of homogeneous greenhouse gases", Atmospheres, DOI: 10.1002/2015JD024569

http://onlinelibrary.wiley.com/doi/10.1002/2015JD024569/abstract (http://onlinelibrary.wiley.com/doi/10.1002/2015JD024569/abstract)

Abstract: "Radiative forcing of a homogeneous greenhouse gas (HGG) can be very inhomogeneous because the forcing is dependent on other atmospheric and surface variables. In the case of doubling CO2, the monthly mean instantaneous forcing at the top of the atmosphere is found to vary geographically and temporally from positive to negative values, with the range (−2.5 – 5.1 W m−2) being more than three times the magnitude of the global mean value (2.3 W m−2). The vertical temperature change across the atmospheric column (temperature lapse rate) is found to be the best single predictor for explaining forcing variation. In addition, the masking effects of clouds and water vapor also contribute to forcing inhomogeneity. A regression model that predicts forcing from geophysical variables is constructed. This model can explain more than 90% of the variance of the forcing. Applying this model to analyzing the forcing variation in the CMIP5 models, we find that inter-model discrepancy in CO2 forcing caused by model climatology leads to considerable discrepancy in their projected change in poleward energy transport."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on February 22, 2016, 06:36:48 PM
The linked (open access) reference cites yet another example of inhomogeneity in atmospheric CO₂ distribution, in this case a 2009-2010 step (see image & caption) in atmospheric CO₂ difference between the Northern & Southern Hemispheres.  This difference appears to be due to a sustained (at least until 2015) change in atmospheric circulation; which must also be modeled by future state of the art ESMs:

Francey, R. J. and Frederiksen, J. S.: The 2009–2010 step in atmospheric CO2 interhemispheric difference, Biogeosciences, 13, 873-885, doi:10.5194/bg-13-873-2016, 2016.

http://www.biogeosciences.net/13/873/2016/ (http://www.biogeosciences.net/13/873/2016/)

Abstract. The annual average CO2 difference between baseline data from Mauna Loa and the Southern Hemisphere increased by  ∼  0.8 µmol mol−1 (0.8 ppm) between 2009 and 2010, a step unprecedented in over 50 years of reliable data. We find no evidence for coinciding, sufficiently large source and sink changes. A statistical anomaly is unlikely due to the highly systematic nature of the variation in observations. An explanation for the step, and the subsequent 5-year stability in this north–south difference, involves interhemispheric atmospheric exchange variation. The selected data describing this episode provide a critical test for studies that employ atmospheric transport models to interpret global carbon budgets and inform management of anthropogenic emissions.


Caption: "Figure 1. North–south differences and growth rates in CO2 since 1990. Panel (a) shows, on the left axis, annual average (January–December) 1C (ppm) from three programs – CSIRO, NOAA (mlo–cgo), and SIO (mlo–spo) – plotted mid-year. On the right axis are reported anthropogenic emissions (dashed line), with the correction suggested by Francey et al. (2013) (shaded), scaled so that the overall slope is similar to that from the long-term mlo–spo SIO record. Panel (b): CSIRO (mlo, cgo, spo) and NOAA (mlo) growth rates, dC / dt , plotted mid- month."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on February 22, 2016, 07:28:14 PM
The linked (open access) reference indicates that uncertainty with warming related microbial drive soil CO₂ efflux, is limiting ESMs projection capabilities.  The paper compares to possible nonlinear microbial models and finds that one results in more positive feedback than the other, and it makes projections that may allow researchers to determine which microbial model is more correct:

Wang, Y. P., Jiang, J., Chen-Charpentier, B., Agusto, F. B., Hastings, A., Hoffman, F., Rasmussen, M., Smith, M. J., Todd-Brown, K., Wang, Y., Xu, X., and Luo, Y. Q.: Responses of two nonlinear microbial models to warming and increased carbon input, Biogeosciences, 13, 887-902, doi:10.5194/bg-13-887-2016, 2016

http://www.biogeosciences.net/13/887/2016/ (http://www.biogeosciences.net/13/887/2016/)

Abstract. A number of nonlinear microbial models of soil carbon decomposition have been developed. Some of them have been applied globally but have yet to be shown to realistically represent soil carbon dynamics in the field. A thorough analysis of their key differences is needed to inform future model developments. Here we compare two nonlinear microbial models of soil carbon decomposition: one based on reverse Michaelis–Menten kinetics (model A) and the other on regular Michaelis–Menten kinetics (model B). Using analytic approximations and numerical solutions, we find that the oscillatory responses of carbon pools to a small perturbation in their initial pool sizes dampen faster in model A than in model B. Soil warming always decreases carbon storage in model A, but in model B it predominantly decreases carbon storage in cool regions and increases carbon storage in warm regions. For both models, the CO2 efflux from soil carbon decomposition reaches a maximum value some time after increased carbon input (as in priming experiments). This maximum CO2 efflux (Fmax) decreases with an increase in soil temperature in both models. However, the sensitivity of Fmax to the increased amount of carbon input increases with soil temperature in model A but decreases monotonically with an increase in soil temperature in model B. These differences in the responses to soil warming and carbon input between the two nonlinear models can be used to discern which model is more realistic when compared to results from field or laboratory experiments. These insights will contribute to an improved understanding of the significance of soil microbial processes in soil carbon responses to future climate change.
Title: Re: Modelling the Anthropocene
Post by: sidd on February 22, 2016, 09:42:14 PM
We have discussed Sugihara's technique for cross convergent mapping in another thread, and I came across a related and possibly more powerful method by Liang, with a climate example worked out explicitly for the ElNino/Indian ocean dipole data, and now by Stips. The references are open access

Liang(2015) doi:10.1103/PhysRevE.90.052150
Stips(2016) doi:10.1038/srep21691

There may be a way to apply this to detect coupled variables, as opposed to detecting coupling after being presented a pair or group of variables, and there are applications to Francis' self organizing maps method also. But I have not thought it through, yet. Comments ?

sidd
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on February 22, 2016, 10:01:48 PM
sidd,

Thanks for the Stips et al (2016) open source reference.  The paper points-out the sometimes forgotten issue that paleo cases of global warming were all driven by solar induced radiative forcing with subsequent warming the produced GHG feedback; while today's global warming is driven by GHG induced radiative forcing.  Furthermore, the paper makes it clear that the lag time associated with our current GHG radiative forcing is longer than the paleo cases.  This indicates to me that we have collectively entered into a "Faustian Bargain", and soon we will have hell to pay as all of the feedbacks from decades of GHG emissions are finally coming home to roost:

http://www.nature.com/articles/srep21691 (http://www.nature.com/articles/srep21691)

Best,
ASLR
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on February 23, 2016, 11:50:09 PM
The linked reference indicates numerous studies have been conducted that indicate the positive feedback of soil respiration to single global climate change factor; however, the linked reference one of the first to example the influence of multiple concurrent factors.  They find that when multiple climate change factors are applied concurrently, the associated soil respiration feedback becomes still more positive.  Hopefully future ESM projects will consider such synergistic effects:

Lingyan Zhou, Xuhui Zhou, Junjiong Shao, Yuanyuan Nie, Yanghui He, Liling Jiang, Zhuoting Wu & Shahla Hosseini Bai (19 February 2016), "Interactive effects of global change factors on soil respiration and its components: a meta-analysis", Global Change Biology, DOI: 10.1111/gcb.13253


http://onlinelibrary.wiley.com/doi/10.1111/gcb.13253/abstract (http://onlinelibrary.wiley.com/doi/10.1111/gcb.13253/abstract)


Abstract: "As the second largest carbon (C) flux between the atmosphere and terrestrial ecosystems, soil respiration (Rs) plays vital roles in regulating atmospheric CO2 concentration ([CO2]) and climatic dynamics in the Earth system. Although numerous manipulative studies and a few meta-analyses have been conducted to determine the responses of Rs and its two components (i.e., autotrophic [Ra] and heterotrophic [Rh] respiration) to single global change factors, the interactive effects of the multiple factors are still unclear. In this study, we performed a meta-analysis of 150 multiple-factor (≥ 2) studies to examine the main and interactive effects of global change factors on Rs and its two components. Our results showed that elevated [CO2] (E), nitrogen addition (N), irrigation (I), and warming (W) induced significant increases in Rs by 28.6%, 8.8%, 9.7%, and 7.1%, respectively. The combined effects of the multiple factors: EN, EW, DE, IE, IN, IW, IEW and DEW, were also significantly positive on Rs to a greater extent than those of the single-factor ones. For all the individual studies, the additive interactions were predominant on Rs (90.6%) and its components (≈70.0%) relative to synergistic and antagonistic ones. However, the different combinations of global-change factors (e.g., EN, NW, EW, IW) indicated that the three types of interactions were all important, with two combinations for synergistic effects, two for antagonistic, and five for additive when at least eight independent experiments were considered. In addition, the interactions of elevated [CO2] and warming had opposite effects on Ra and Rh, suggesting that different processes may influence their responses to the multi-factor interactions. Our study highlights the crucial importance of the interactive effects among the multiple factors on Rs and its components, which could inform regional and global models to assess the climate-biosphere feedbacks and improve predictions of the future states of the ecological and climate systems."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on February 25, 2016, 04:19:46 PM
The linked paper emphasizes the importance of continued observation of the oceans, not only with regards to heat uptake but also with regards to salinity & the water cycle:
Paul J. Durack, Tong Lee, Nadya T. Vinogradova & Detlef Stammer (2016), "Keeping the lights on for global ocean salinity observation", Nature Climate Change, Volume: 6, Pages: 228–231, doi:10.1038/nclimate2946


http://www.nature.com/nclimate/journal/v6/n3/full/nclimate2946.html (http://www.nature.com/nclimate/journal/v6/n3/full/nclimate2946.html)


Summary: "Insights about climate are being uncovered thanks to improved capacities to observe ocean salinity, an essential climate variable. However, cracks are beginning to appear in the ocean observing system that require prompt attention if we are to maintain the existing, hard-won capacity into the near future."

See also:
http://phys.org/news/2016-02-ocean.html (http://phys.org/news/2016-02-ocean.html)

Extract: "Oceanographer Paul Durack of the Laboratory's Program for Climate Modeling and Intercomparison (PCMDI) recently opined about the importance of ocean salinity observations and needed urgent attention for the ocean observing system in the journal, Nature Climate Change.

The global water cycle—where, when and how it rains, and the corresponding changes to water availability—are as pressing an issue as any when it comes to climate change.
The global ocean is a great place to ascertain observed water cycle changes, as it contains 97 percent of the Earth's water and is where 80 percent of fluxes—water exchanges at the Earth's surface—occur."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on February 29, 2016, 07:07:57 PM
The linked reference discusses a new framework for defining and calibrating climate sensitivity, from a modelling perspective, that would allow for both linear and nonlinear consideration of changes in climate sensitivity at decadal timescales:

Francesco Ragone, Valerio Lucarini & Frank Lunkeit (2016), "A new framework for climate sensitivity and prediction: a modelling perspective", Climate Dynamics, Volume 46, Issue 5, pp 1459-1471, DOI: 10.1007/s00382-015-2657-3


http://link.springer.com/article/10.1007%2Fs00382-015-2657-3 (http://link.springer.com/article/10.1007%2Fs00382-015-2657-3)


Abstract: "The sensitivity of climate models to increasing CO2 concentration and the climate response at decadal time-scales are still major factors of uncertainty for the assessment of the long and short term effects of anthropogenic climate change. While the relative slow progress on these issues is partly due to the inherent inaccuracies of numerical climate models, this also hints at the need for stronger theoretical foundations to the problem of studying climate sensitivity and performing climate change predictions with numerical models. Here we demonstrate that it is possible to use Ruelle’s response theory to predict the impact of an arbitrary CO2 forcing scenario on the global surface temperature of a general circulation model. Response theory puts the concept of climate sensitivity on firm theoretical grounds, and addresses rigorously the problem of predictability at different time-scales. Conceptually, these results show that performing climate change experiments with general circulation models is a well defined problem from a physical and mathematical point of view. Practically, these results show that considering one single CO2 forcing scenario is enough to construct operators able to predict the response of climatic observables to any other CO2 forcing scenario, without the need to perform additional numerical simulations. We also introduce a general relationship between climate sensitivity and climate response at different time scales, thus providing an explicit definition of the inertia of the system at different time scales. This technique allows also for studying systematically, for a large variety of forcing scenarios, the time horizon at which the climate change signal (in an ensemble sense) becomes statistically significant. While what we report here refers to the linear response, the general theory allows for treating nonlinear effects as well. These results pave the way for redesigning and interpreting climate change experiments from a radically new perspective."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on March 01, 2016, 07:50:19 PM
The linked presentation provides a nice overview of Earth System Modeling through about 2013:


Understanding the Earth System through Numerical Modeling: Crossing the Disciplinary Frontiers (Invited Presentation)
Monday, 11 January 2016: 1:30 PM
V. Ramaswamy

https://ams.confex.com/ams/96Annual/webprogram/Paper291505.html

https://ams.confex.com/ams/96Annual/videogateway.cgi/id/31518?recordingid=31518


Abstract: "Mathematical modeling based on fundamental scientific principles has been the core analytical tool for the understanding and prediction of changes in the Earth's climate system due to natural and human-influenced drivers e.g., aerosols from volcanic eruptions, changes in solar irradiance, greenhouse gases, and pollution aerosols. Beginning about the middle of the last century, and with advances in computing over the decades, numerical modeling investigations have expanded from the very first examination of the changes in the planetary radiation balance to incorporating systematically more and more of the factors affecting climate and examining the resulting influences. Steady advances in theoretical basis and modeling have led to the development and coupling of the atmosphere to land, ocean, and ice components, permitting a more comprehensive assessment of the impacts. With inclusion in more recent decades of atmospheric chemistry, biogeochemical cycles, and ecosystem science, models can increasingly capture more of the “Earth System” response to the drivers. The evolution in modeling, combined with advances in observations, has enabled increasingly challenging scientific questions about environmental changes to be better addressed, including the what, why, and how are the changes manifest in different regions, and what lies ahead in the future. In this presentation, we examine the evolution in the modeling of the Earth System response to the drivers, the current state of understanding including the uncertainties, and future projections and predictions. We also explore how the growth in knowledge of the intersections among the various disciplines constituting the Earth System has, through observations and modeling, yielded inputs into decision-making relevant for vulnerabilities, mitigation and adaptation."

See also:
https://ams.confex.com/ams/96Annual/webprogram/8AEROSOL.html
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on March 08, 2016, 05:13:44 PM
The linked reference uses near-term computer models to evaluate the role of different areas of the ocean on driving climate variability.  Among other conclusions, the reference finds: (a) the state of the ocean is always important for climate projections; (b) the deep ocean state has a pronounced impact on ocean circulation; and (c) the state of the ocean at the poles and the Equator are more dominate on climate response than is the state of the ocean at mid-latitudes.  I note that the AR5 projections poorly account for initial ocean states, and I hope that AR6 projections will do a better job of including the important influence of these ocean initial states (like the PDO/IPO and ENSO cycles, as well as hosing from ice sheet melting):

A. Carrassi , V. Guemas, F. J. Doblas-Reyes, D. Volpi & M. Asif (03 March 2016), "Sources of skill in near-term climate prediction: generating initial conditions", Climate Dynamics, pp 1-20, DOI: 10.1007/s00382-016-3036-4


http://link.springer.com/article/10.1007%2Fs00382-016-3036-4 (http://link.springer.com/article/10.1007%2Fs00382-016-3036-4)


Abstract: "This study investigates the role of different areas of the ocean in driving the climate variability. The impact of both global and regional ocean nudging on the climate reconstruction obtained with the climate model EC-Earth v2.3 is studied over the period 1960–2012. Ocean temperature and salinity below the mixed layer are relaxed toward the monthly averages from the ORAS4 ocean reanalysis. Three coupled ocean–atmosphere simulations are considered: (1) global ocean nudging, (2) nudging in the global upper ocean (above 2000 m) and (3) nudging in the mid-latitude ocean and at full ocean depth. The experimental setup allows for identifying local and remote effects of nudging on different geographical areas. The validation is based on the correlation coefficients and the root mean square error skill score and concerns the following variables: ocean heat content, ocean barotropic streamfunction, intensity of the ocean gyres and indexes of convection, sea ice extension, near-surface air and sea surface temperature, and El Niño–Southern Oscillation 3.4 index. The results can be summarized as follows: (1) the positive impact on the reconstruction of the ocean state is found almost everywhere and for most of the analyzed variables, including unconstrained variables and/or regions, (2) deep-ocean nudging shows low impact on sea-surface temperature but a significant impact on the ocean circulation, (3) mid-latitude ocean nudging shows systematically the worst performance pointing at the importance of the poles and tropics in reconstructing the global ocean."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on March 08, 2016, 05:40:03 PM
The linked (open access) reference uses a planned program of large dam construction in the Red River Basin, Southeast Asia, to study the impacts of such large storage operations on model uncertainties under climate change conditions.  They find that without adequately planning for future climate conditions such large storage operations will increase the uncertainties of climate change impacts, and they call for policy makers to adopt appropriate strategies for adaptation for such large storage systems:

Matteo Giuliani, Daniela Anghileri, Andrea Castelletti, Phuong Nam Vu and Rodolfo Soncini-Sessa (2 March 2016), "Large storage operations under climate change: expanding uncertainties and evolving tradeoffs", Environmental Research Letters, Volume 11, Number 3

http://iopscience.iop.org/article/10.1088/1748-9326/11/3/035009/meta (http://iopscience.iop.org/article/10.1088/1748-9326/11/3/035009/meta)

Abstract: "In a changing climate and society, large storage systems can play a key role for securing water, energy, and food, and rebalancing their cross-dependencies. In this letter, we study the role of large storage operations as flexible means of adaptation to climate change. In particular, we explore the impacts of different climate projections for different future time horizons on the multi-purpose operations of the existing system of large dams in the Red River basin (China–Laos–Vietnam). We identify the main vulnerabilities of current system operations, understand the risk of failure across sectors by exploring the evolution of the system tradeoffs, quantify how the uncertainty associated to climate scenarios is expanded by the storage operations, and assess the expected costs if no adaptation is implemented. Results show that, depending on the climate scenario and the time horizon considered, the existing operations are predicted to change on average from -7 to +5% in hydropower production, +35 to +520% in flood damages, and +15 to +160% in water supply deficit. These negative impacts can be partially mitigated by adapting the existing operations to future climate, reducing the loss of hydropower to 5%, potentially saving around 34.4 million US$ year-1 at the national scale. Since the Red River is paradigmatic of many river basins across southeast Asia, where new large dams are under construction or are planned to support fast growing economies, our results can support policy makers in prioritizing responses and adaptation strategies to the changing climate."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on March 08, 2016, 06:01:08 PM
The linked (open access) reference studies recent (after 1997) changes in winter Arctic clouds & their relationships with sea ice and atmospheric conditions; which should be of assistance in improving future model projections:

SANG-YOON JUN, CHANG-HOI HO, JEE-HOON JEONG, YONG-SANG CHOI and BAEK-MIN KIM (2016), "Recent changes in winter Arctic clouds and their relationships with sea ice and atmospheric conditions", Tellus A, 68, 29130, http://dx.doi.org/10.3402/tellusa.v68.29130 (http://dx.doi.org/10.3402/tellusa.v68.29130)

http://www.tellusa.net/index.php/tellusa/article/view/29130 (http://www.tellusa.net/index.php/tellusa/article/view/29130)

Abstract: "Changes in Arctic clouds during boreal winter (December through February) and their relationship with sea ice and atmospheric conditions in recent decades have been examined using satellite and reanalysis data, and they are compared with output data from atmospheric general circulation model (AGCM) experiments. All the datasets used in this study consistently show that cloud amount over the Arctic Ocean (north of 67°N) decreased until the late 1990s but rapidly increased thereafter. Cloud increase in recent decade was a salient feature in the lower troposphere over a large part of the Arctic Sea, in association with obvious increase of lower tropospheric temperature and moisture. The comparison between the two periods before and after 1997 indicates that interannual covariability of Arctic clouds and lower tropospheric temperature and moisture was significantly enhanced after the late 1990s. Large reduction of sea ice cover during boreal winter decreased lower tropospheric static stability and deepened the planetary boundary layer. These changes led to an enhanced upward moisture transport and cloud formation, which led to considerable longwave radiative forcing and, as a result, strengthened the cloud–moisture–temperature relationship in the lower troposphere. AGCM experiments under reduced sea ice conditions support those results obtained by satellite and reanalysis datasets reproducing the increases in cloud amount and lower tropospheric temperature and their enhanced covariability."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on March 12, 2016, 10:39:28 PM
The linked (open access) reference takes into account the implications of the Paris Pact, and also uses ESLD assumptions about climate sensitivity; nevertheless, it projects radiative forcing scenarios that will likely result a commitment to eventually reach a 1.5C GMST rise by 2020 and a commitment to reach a 2C GMST rise by 2030:

Wagner L, Ross I, Foster J, Hankamer B (2016), "Trading Off Global Fuel Supply, CO2 Emissions and Sustainable Development", PLoS ONE 11(3): e0149406, doi:10.1371/journal.pone.0149406


http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0149406 (http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0149406)


Abstract: "The United Nations Conference on Climate Change (Paris 2015) reached an international agreement to keep the rise in global average temperature ‘well below 2°C’ and to ‘aim to limit the increase to 1.5°C’. These reductions will have to be made in the face of rising global energy demand. Here a thoroughly validated dynamic econometric model (Eq 1) is used to forecast global energy demand growth (International Energy Agency and BP), which is driven by an increase of the global population (UN), energy use per person and real GDP (World Bank and Maddison). Even relatively conservative assumptions put a severe upward pressure on forecast global energy demand and highlight three areas of concern. First, is the potential for an exponential increase of fossil fuel consumption, if renewable energy systems are not rapidly scaled up. Second, implementation of internationally mandated CO2 emission controls are forecast to place serious constraints on fossil fuel use from ~2030 onward, raising energy security implications. Third is the challenge of maintaining the international ‘pro-growth’ strategy being used to meet poverty alleviation targets, while reducing CO2 emissions. Our findings place global economists and environmentalists on the same side as they indicate that the scale up of CO2 neutral renewable energy systems is not only important to protect against climate change, but to enhance global energy security by reducing our dependence of fossil fuels and to provide a sustainable basis for economic development and poverty alleviation. Very hard choices will have to be made to achieve ‘sustainable development’ goals."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on March 15, 2016, 09:04:26 PM
The linked presentation (see two images from the presentation) discusses the present challenges facing ESM groups:

Jean-François Lamarque (2016), "Balancing processes, resolution and ensembles in Earth system models"

 http://cpo.noaa.gov/sites/cpo/MAPP/Webinars/2016/01-29-16/Lamarque.pdf (http://cpo.noaa.gov/sites/cpo/MAPP/Webinars/2016/01-29-16/Lamarque.pdf)

Abstract: "Using recent simulation results and model developments, this talk will discuss the present challenges that Earth System modeling group are facing in creating and using the next generation of Earth system models, in particular in the light of the upcoming CMIP6."

See also:
http://cpo.noaa.gov/ClimatePrograms/ModelingAnalysisPredictionsandProjections/MAPPNewsEvents/TabId/506/artmid/1256/articleid/445201/Default.aspx (http://cpo.noaa.gov/ClimatePrograms/ModelingAnalysisPredictionsandProjections/MAPPNewsEvents/TabId/506/artmid/1256/articleid/445201/Default.aspx)

Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on March 23, 2016, 05:37:05 PM
Per the linked peer-reviewed reference, it looks like any future modeling radiative forcing scenarios may well need to increase the contribution from food production due both to unexpectedly high population growth projections and increasingly rich food demands per capita:

Mario Herrero, Benjamin Henderson, Petr Havlík, Philip K. Thornton, Richard T. Conant, Pete Smith, Stefan Wirsenius, Alexander N. Hristov, Pierre Gerber, Margaret Gill, Klaus Butterbach-Bahl, Hugo Valin, Tara Garnett & Elke Stehfest (2016), "Greenhouse gas mitigation potentials in the livestock sector" Nature Climate Change, doi:10.1038/nclimate2925


http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2925.html (http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2925.html)

Abstract: "The livestock sector supports about 1.3 billion producers and retailers, and contributes 40–50% of agricultural GDP. We estimated that between 1995 and 2005, the livestock sector was responsible for greenhouse gas emissions of 5.6–7.5 GtCO2e yr−1. Livestock accounts for up to half of the technical mitigation potential of the agriculture, forestry and land-use sectors, through management options that sustainably intensify livestock production, promote carbon sequestration in rangelands and reduce emissions from manures, and through reductions in the demand for livestock products. The economic potential of these management alternatives is less than 10% of what is technically possible because of adoption constraints, costs and numerous trade-offs. The mitigation potential of reductions in livestock product consumption is large, but their economic potential is unknown at present. More research and investment are needed to increase the affordability and adoption of mitigation practices, to moderate consumption of livestock products where appropriate, and to avoid negative impacts on livelihoods, economic activities and the environment."


See also:
http://www.carbonbrief.org/guest-post-failure-to-tackle-food-demand-could-make-1-point-5-c-limit-unachievable (http://www.carbonbrief.org/guest-post-failure-to-tackle-food-demand-could-make-1-point-5-c-limit-unachievable)

Extract: "The emissions pathway we’d need to follow for a 66% chance of staying within 1.5C suggests that food-related emissions at current levels would take up our entire greenhouse gas budget in 2050.
That means unless things change – radically – our demand for food could leave no space for emissions from any of the other services we require to live our daily lives.
In short, our demand for food alone could virtually guarantee that the Paris aspirations are unachievable.
There are three possible ways we could respond to this sobering conclusion:
- We carry on as we are and miss the Paris targets, and therefore perhaps lock us into 4-5C of global warming by the end of the century;
- We rely on research and innovation to find ways to significantly increase yields to reduce the rate of land conversion and develop carbon capture and storage, or
- We recognise that demand for food is driving emissions and work to change that to meet the supply-side improvements halfway.  "
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on March 23, 2016, 05:41:50 PM
Per the linked reference it appears that previously under-appreciated inactions between multiple climate change tipping points; means that the climate consequences for any given assumed forcing scenario is likely worse than previously appreciated by mainstream scientists and policy makers.  The authors call for more aggressive reductions in future GHG emissions.

Yongyang Cai, Timothy M. Lenton & Thomas S. Lontzek (2016), "Risk of multiple interacting tipping points should encourage rapid CO2 emission reduction", Nature Climate Change, doi:10.1038/nclimate2964


http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2964.html (http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2964.html)


Abstract: "Evidence suggests that several elements of the climate system could be tipped into a different state by global warming, causing irreversible economic damages. To address their policy implications, we incorporated five interacting climate tipping points into a stochastic-dynamic integrated assessment model, calibrating their likelihoods and interactions on results from an existing expert elicitation. Here we show that combining realistic assumptions about policymakers’ preferences under uncertainty, with the prospect of multiple future interacting climate tipping points, increases the present social cost of carbon in the model nearly eightfold from US$15 per tCO2 to US$116 per tCO2. Furthermore, passing some tipping points increases the likelihood of other tipping points occurring to such an extent that it abruptly increases the social cost of carbon. The corresponding optimal policy involves an immediate, massive effort to control CO2 emissions, which are stopped by mid-century, leading to climate stabilization at <1.5 °C above pre-industrial levels."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on March 23, 2016, 06:29:19 PM
The linked reference indicates that the largest reason for the methane emissions plateau from 1999 to 2006 was the collapse of the USSR; while the most likely reason for the recent surge in methane emissions is food production in South, East, and Southeast Asia.  The authors are also concerned to further global warming could trigger other sources of methane emissions.  This information can be used to better calibrate both models and radiative forcing scenarios for AR6:


H. Schaefer, Sara E. Mikaloff Fletcher, Cordelia Veidt, Keith R. Lassey, Gordon W. Brailsford, Tony M. Bromley, Edward J. Dlugokencky, Sylvia E. Michel, John B. Miller, Ingeborg Levin, Dave C. Lowe, Ross J. Martin, Bruce H. Vaughn & James W. C. White (2016), "A 21st century shift from fossil-fuel to biogenic methane emissions indicated by 13CH4", Science  DOI: 10.1126/science.aad2705


http://science.sciencemag.org/content/early/2016/03/09/science.aad2705 (http://science.sciencemag.org/content/early/2016/03/09/science.aad2705)

Abstract: "Between 1999 and 2006, a plateau interrupted the otherwise continuous increase of atmospheric methane concentration [CH4] since pre-industrial times. Causes could be sink variability or a temporary reduction in industrial or climate sensitive sources. We reconstruct the global history of [CH4] and its stable carbon isotopes from ice cores, archived air and a global network of monitoring stations. A box-model analysis suggests that diminishing thermogenic emissions, probably from the fossil-fuel industry, and/or variations in the hydroxyl CH4-sink caused the [CH4]-plateau. Thermogenic emissions didn’t resume to cause the renewed [CH4]-rise after 2006, which contradicts emission inventories. Post-2006 source increases are predominantly biogenic, outside the Arctic, and arguably more consistent with agriculture than wetlands. If so, mitigating CH4-emissions must be balanced with the need for food production."

See also:
http://www.sciencemag.org/news/2016/03/soviet-collapse-might-explain-mysterious-trend-global-methane-emissions (http://www.sciencemag.org/news/2016/03/soviet-collapse-might-explain-mysterious-trend-global-methane-emissions)
&
http://phys.org/news/2016-03-scientists-attribute-methane-agriculture.html (http://phys.org/news/2016-03-scientists-attribute-methane-agriculture.html)

Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on March 23, 2016, 06:42:03 PM
The following is a re-post from the "UN Climate Agreement - Paris 2015" thread:

The linked reference uses empirically informed levels of strategic reasoning to calibrate model simulations of international negotiations on climate change.  First, the research shows that when a tipping point threshold has been clearly identified then it is easier to achieve an international agree such as the Paris Pact; thus using inversion the fact that the Paris Pact was achieved is an indication that clear evidence of an impending tipping point was presented to the negotiators at CoP21.  Second, the research shows that "policy elites" (like those in the EU & the USA) often use higher degrees of strategic reasoning to try to beggar their neighbors when negotiating national emission levels within such agreements; which indicates that it will likely be extremely difficult to ratchet-up additional emission restriction; which increases the probability for climate catastrophe this century:

Vilhelm Verendel, Daniel J. A. Johansson & Kristian Lindgren (2016), "Strategic reasoning and bargaining in catastrophic climate change games", Nature Climate Change, Volume: 6, Pages: 265–268, doi:10.1038/nclimate2849

http://www.nature.com/nclimate/journal/v6/n3/full/nclimate2849.html (http://www.nature.com/nclimate/journal/v6/n3/full/nclimate2849.html)

Abstract: "Two decades of international negotiations show that agreeing on emission levels for climate change mitigation is a hard challenge. However, if early warning signals were to show an upcoming tipping point with catastrophic damage, theory and experiments suggest this could simplify collective action to reduce greenhouse gas emissions. At the actual threshold, no country would have a free-ride incentive to increase emissions over the tipping point, but it remains for countries to negotiate their emission levels to reach these agreements. We model agents bargaining for emission levels using strategic reasoning to predict emission bids by others and ask how this affects the possibility of reaching agreements that avoid catastrophic damage. It is known that policy elites often use a higher degree of strategic reasoning, and in our model this increases the risk for climate catastrophe. Moreover, some forms of higher strategic reasoning make agreements to reduce greenhouse gases unstable. We use empirically informed levels of strategic reasoning when simulating the model."
Title: Re: Modelling the Anthropocene
Post by: sidd on March 23, 2016, 06:46:27 PM
That Cai paper has an interesting figure on change in social cost of carbon as various (interacting) tipping points are reached, each of whinch may induce other tipping points to be exceeded. I have attached Fig 3. I am suspicious of integrated assessment models, but i do like this paper.
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on March 23, 2016, 09:00:14 PM
That Cai paper has an interesting figure on change in social cost of carbon as various (interacting) tipping points are reached, each of whinch may induce other tipping points to be exceeded. I have attached Fig 3. I am suspicious of integrated assessment models, but i do like this paper.

While I like the methodology used by the authors, I disagree with the timing and sequencing of the tipping points that they evaluate, & I draw particular attention to the risk of the WAIS beginning to collapse rapidly by 2050.  It seems to me that Cai et al (2016) would benefit from reading Hansen et al (2016), with regards to the risks associated with both WAIS collapse and combined WAIS & GIS collapse.  Furthermore, due to wildfires and deforestation, I think that the Amazon Basin in much closer to collapse than the authors indicate.
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on April 01, 2016, 06:31:13 PM
The linked reference discusses how the latent energy transport of atmospheric planetary waves contributes to Arctic Amplification:

Rune G. Graversen and Mattias Burtu (2016), "Arctic amplification enhanced by latent energy transport of atmospheric planetary waves", Quarterly Journal of the Royal Meteorological Society, DOI: 10.1002/qj.2802


http://onlinelibrary.wiley.com/doi/10.1002/qj.2802/abstract (http://onlinelibrary.wiley.com/doi/10.1002/qj.2802/abstract)

Abstract: "The atmospheric northward energy transport plays a crucial role for the Arctic climate; this transport brings to the Arctic an amount of energy comparable to that provided directly by the sun. The transport is accomplished by atmospheric waves – for instance large-scale planetary waves and meso-scale cyclones – and the zonal-mean circulation. These different components of the energy transport impact the Arctic climate differently.
A split of the transport into stationary and transient waves constitutes a traditional way of decomposing the transport. However this procedure does not take into account the transport accomplished separately by the planetary and synoptic-scale waves. Here a Fourier decomposition is applied, which decomposes the transport with respect to zonal wave numbers. Reanalysis and model data reveal that the planetary waves impact Arctic temperatures much more than do synoptic-scale waves. In addition the latent transport by these waves affects the Arctic climate more than does the dry-static part. Finally, the EC-Earth model suggests that changes of the energy transport over the 21 st century will contribute to Arctic warming, despite the fact that in this model the total energy transport to the Arctic will decrease. This apparent contradicting result is due to the cooling induced by a decrease of the dry-static transport by planetary waves being more than compensated for by a warming caused by the latent counterpart."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on April 04, 2016, 10:39:51 AM
The linked reference discusses state-of-the-art work to model trends in the ocean carbon sink; however, they found that it is still too early to make clear projections as to whether this critical sink will increase, or decrease, with continued global warming:

Galen A. McKinley, Darren J. Pilcher, Amanda R. Fay, Keith Lindsay, Matthew C. Long & Nicole S. Lovenduski (25 February 2016), "Timescales for detection of trends in the ocean carbon sink", Nature, Volume: 530, Pages: 469–472, doi:10.1038/nature16958


http://www.nature.com/nature/journal/v530/n7591/full/nature16958.html (http://www.nature.com/nature/journal/v530/n7591/full/nature16958.html)


Abstract: "The ocean has absorbed 41 per cent of all anthropogenic carbon emitted as a result of fossil fuel burning and cement manufacture. The magnitude and the large-scale distribution of the ocean carbon sink is well quantified for recent decades. In contrast, temporal changes in the oceanic carbon sink remain poorly understood. It has proved difficult to distinguish between air-to-sea carbon flux trends that are due to anthropogenic climate change and those due to internal climate variability. Here we use a modelling approach that allows for this separation, revealing how the ocean carbon sink may be expected to change throughout this century in different oceanic regions. Our findings suggest that, owing to large internal climate variability, it is unlikely that changes in the rate of anthropogenic carbon uptake can be directly observed in most oceanic regions at present, but that this may become possible between 2020 and 2050 in some regions."

See also:
http://phys.org/news/2016-02-climate-ocean-carbon.html (http://phys.org/news/2016-02-climate-ocean-carbon.html)

Extract: "The researchers also checked the model against actual ocean observations. "What we find is that observations today are not sufficient to be able to see change in the ocean-carbon sink," McKinley explains. "We can see that there is a sink, but at any one location, we don't have enough data to say that the sink is increasing or decreasing.""
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on May 19, 2016, 08:56:20 PM
Per the linked article, ACME Version 1 is on schedule and ready to lock & load (see attached image from the atmosphere module):


https://climatechangescience.ornl.gov/content/acme%E2%80%94scaling-heights

Extract: "More important, the team, which consists of eight national laboratories, the National Center for Atmospheric Research, four academic institutions, and one private-sector company, is on schedule for release of Version 1 of the ACME model in June 2016.
The major activity this past year was completion of Version 1 of the model, based on the Community Earth System Model or CESM. The team has been running tests on the model since late last year. After the release in June, the team will start a series of science experiments, in the works for 2 years, that will run from July 2016 through July 2017."
...
On the land model side, the most significant advance made this past year was integrating the phosphorus cycle. In the past, Thornton points out, CESM was unique in the community of global ESMs for including both a nitrogen cycle and a carbon cycle. No Earth system model to date, however, has included phosphorus. ACME Version 1 will include carbon, nitrogen, and phosphorus cycles, based on work by Xiaojuan Yang, a CCSI early career scientist. “This is world class new science that no other coupled model has, and it will have an important impact on predictions of future climate,” says Thornton. “We’re really excited about that.”

Another innovation the team has introduced is what’s called “reactive transport modeling capability.” This is a new, more sophisticated way to solve the coupled hydrology-temperature (freeze-thaw) dynamics and biogeochemistry reactions in the soil and between the soil and vegetation. Thornton says the approach more consistently integrates the mass, energy, and biological components of the model, including the phosphorus cycle work.
...
Daniel M. Ricciuto from CCSI’s Integrative Ecosystem Science group (formerly known as the Terrestrial Ecosystem and Carbon Cycle Science group) works on the uncertainty quantification (UQ) component of the ACME project. Thornton says it’s a formal framework to estimate the uncertainty associated with some of the model parameters to optimize model predictions. That same framework is used to estimate parameter values for the model to optimize the metrics of model performance against other independent observations such as those from satellites. Tuning parameters in the model that are uncertain based on actual measurements will facilitate model optimization.
...
Achievements by the ACME Atmospheric Model team have been no less impressive, but perhaps the most exciting have been in the area of high-resolution simulation. Most global models today don’t represent the impacts of climate change on water resources very well in mountainous regions or other regions with complex terrain. To address this, the team has developed a topography-based subgrid system based on high-resolution global elevation data from various sources. This results in a greater number of subgrid units over regions of complex terrain, such as mountains, leading to better representation of precipitation and surface water flow in such regions. For consistency, the same high-resolution subgrid system is also being used for the ACME Land Model.
...
Pat Worley is leading the performance evaluation effort, both for ORNL aspects of the project and for the project as a whole. Up to this point, that’s mainly been a matter of ensuring all the subcomponents of the system run as quickly as possible on Titan and other leadership computing resources and then ensuring that when they are coupled they continue to run quickly. The performance target they are aiming for is 5 simulation years per day for the highest resolution simulations.

One of the goals of the ACME project is to optimize model performance for future leadership computing architectures, and Thornton says that the Performance Task Team is already preparing for the next generation of computers, due in 2017 (the “mid-machines” before exascale such as ORNL’s Summit). As part of this preparation, the team submitted a successful proposal to the Oak Ridge Leadership Computing Facility’s Center for Accelerated Application Readiness or CAAR program. Through CAAR, the ACME team will gain early access to Summit’s hybrid CPU–GPU architecture and technical support for software development. And of course, Worley and the team are already looking at model development and needs for the exascale model.
...
Workflow is the final piece being worked on in CCSI. The goal is to have a robust system that domain scientists can use efficiently and effectively without a lot of tedious work up front. The workflow tool under construction is really a set of tools operating under a web-based user interface that will be in place when Version 1 is rolled out in June—available to the whole world. Not having a workflow tool such as the one being designed restricts the science that can be done and the use of the model to that very small population of computer programmers/modelers/software engineers who are also domain scientists. “So by looking at workflow, we really hope to open it up to a larger community,” Thornton says."
Title: Re: Modelling the Anthropocene
Post by: theoldinsane on May 20, 2016, 12:06:18 AM
"Per the linked article, ACME Version 1 is on schedule and ready to lock & load (see attached image from the atmosphere module):"

Thank you AbruptSLR. If I understand it right it will be a big step forward in Climate Change science and understanding?
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on May 20, 2016, 12:29:41 AM
"Per the linked article, ACME Version 1 is on schedule and ready to lock & load (see attached image from the atmosphere module):"

Thank you AbruptSLR. If I understand it right it will be a big step forward in Climate Change science and understanding?

Yes, ACME will represent a big step forward, and you might also want to look at the thread on:

Climate Model Test Beds: Calibrating Nonlinear ESMs focused on ACME:
http://forum.arctic-sea-ice.net/index.php/topic,1478.msg70074.html#msg70074 (http://forum.arctic-sea-ice.net/index.php/topic,1478.msg70074.html#msg70074)


Title: Re: Modelling the Anthropocene
Post by: theoldinsane on May 20, 2016, 01:24:26 AM
"Per the linked article, ACME Version 1 is on schedule and ready to lock & load (see attached image from the atmosphere module):"

Thank you AbruptSLR. If I understand it right it will be a big step forward in Climate Change science and understanding?

Yes, ACME will represent a big step forward, and you might also want to look at the thread on:

Climate Model Test Beds: Calibrating Nonlinear ESMs focused on ACME:
http://forum.arctic-sea-ice.net/index.php/topic,1478.msg70074.html#msg70074 (http://forum.arctic-sea-ice.net/index.php/topic,1478.msg70074.html#msg70074)

AbruptSLR, a few years ago I started to read some posts in this forum. Back then I was interested mostly in the melting of the Arctic sea ice and thought the Antarctic situation was not so important. But your continuous writings changed that. "Water erodes rock not by its power but by tenacity". That is what you have done with me. But now I think I have a much more holistic view of ongoing climate change and that is scary knowledge. Although I am old, still I see forward to learne more. Big thanks to you for your willingness to teach us about very difficult and scary issues.

Keep up the good work!

Back to lurking...
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on May 22, 2016, 07:26:08 PM
The linked article provides valuable discussion about using regional climate models compared to global models.  Such discussions help to better understand the approach being adopted by the ACME project:

http://www.realclimate.org/index.php/archives/2016/05/do-regional-climate-models-add-value-compared-to-global-models/#more-19412 (http://www.realclimate.org/index.php/archives/2016/05/do-regional-climate-models-add-value-compared-to-global-models/#more-19412)

Extract: "We need to apply downscaling to compute the local details. Downscaling may be done through empirical-statistical downscaling (ESD) or regional climate models (RCMs) with a much finer grid. Both take the crude (low-resolution) solution provided by the GCMs and include finer topographical details (boundary conditions) to calculate more detailed information. However, does more details translate to a better representation of the world?
The question of “added value” was an important topic at the International Conference on Regional Climate conference hosted by CORDEX of the World Climate Research Programme (WCRP). The take-home message was mixed on whether RCMs provide a better description of local climatic conditions than the coarser GCMs.
RCMs can add details such as the influence of lakes, sea breeze, mountain ranges, and sharper weather fronts. Systematic differences between results from RCMs and observations may not necessarily be less than those for GCMs, however."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on May 24, 2016, 11:25:28 PM
The linked reference indicates society currently only looks at the impacts of climate of individual sectors (like agriculture) in isolation; which is likely to misrepresent the true impacts.  For example the Paris Pact does not limit carbon emissions from agriculture yet it is impossible to achieve its stated goals when considering the impacts of agriculture on the climate:

Paula A. Harrison et al. Climate change impact modelling needs to include cross-sectoral interactions, Nature Climate Change (2016). DOI: 10.1038/nclimate3039


http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate3039.html (http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate3039.html)

Abstract: "Climate change impact assessments often apply models of individual sectors such as agriculture, forestry and water use without considering interactions between these sectors. This is likely to lead to misrepresentation of impacts, and consequently to poor decisions about climate adaptation. However, no published research assesses the differences between impacts simulated by single-sector and integrated models. Here we compare 14 indicators derived from a set of impact models run within single-sector and integrated frameworks across a range of climate and socio-economic scenarios in Europe. We show that single-sector studies misrepresent the spatial pattern, direction and magnitude of most impacts because they omit the complex interdependencies within human and environmental systems. The discrepancies are particularly pronounced for indicators such as food production and water exploitation, which are highly influenced by other sectors through changes in demand, land suitability and resource competition. Furthermore, the discrepancies are greater under different socio-economic scenarios than different climate scenarios, and at the sub-regional rather than Europe-wide scale."

See also:
http://phys.org/news/2016-05-full-picture-climate-impacts.html (http://phys.org/news/2016-05-full-picture-climate-impacts.html)

Extract: "How can society plan for the future if we only look at individual issues in isolation? Climate change impact studies typically focus on a single sector such as agriculture, forestry or water, ignoring the implications of how different sectors interact. A new study, published in Nature Climate Change, suggests that an integrated, cross-sectoral approach to climate change assessment is needed to provide a more complete picture of impacts that enables better informed decisions about climate adaptation.


Using the CLIMSAVE Integrated Assessment Platform (IAP), which links models of agriculture, forestry, urban growth, land use, water resources, flooding and biodiversity, the new study compares single-sector and integrated modelling approaches and their outcomes.
The resulting discrepancies are particularly evident for indicators such as food production and water exploitation which are highly influenced by other sectors through changes in demand, land suitability and resource competition.
"This analysis has demonstrated quantitatively for the first time the uncertainty arising from a single sector perspective. This highlights the importance of developing adaptation plans that are robust to changes in climate and socio-economic pathways and that take account of cross-sectoral interactions", concludes Dr. Harrison."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on June 06, 2016, 07:49:35 PM
The linked reference discusses the dominate role that atmospheric moisture transport plays in the onset of Arctic sea ice melting, and identifies an associate trend for earlier spring ice melting, during recent decades due to AGW:

Jonas Mortin,Gunilla Svensson, Rune G. Graversen, Marie-Luise Kapsch, Julienne C. Stroeve & Linette N. Boisvert (3 June 2016), "Melt onset over Arctic sea ice controlled by atmospheric moisture transport", Geophysical Research Letters, DOI: 10.1002/2016GL069330

http://onlinelibrary.wiley.com/doi/10.1002/2016GL069330/abstract (http://onlinelibrary.wiley.com/doi/10.1002/2016GL069330/abstract)

Abstract: "The timing of melt onset affects the surface energy uptake throughout the melt season. Yet the processes triggering melt and causing its large interannual variability are not well understood. Here, we show that melt onset over Arctic sea ice is initiated by positive anomalies of water vapor, clouds, and air temperatures that increase the downwelling longwave radiation (LWD) to the surface. The earlier melt onset occurs, the stronger are these anomalies. Downwelling shortwave radiation (SWD) is smaller than usual at melt onset, indicating that melt is not triggered by SWD. When melt occurs early, an anomalously opaque atmosphere with positive LWD anomalies preconditions the surface for weeks preceding melt. In contrast, when melt begins late, clearer than usual conditions are evident prior to melt. Hence, atmospheric processes are imperative for melt onset. It is also found that spring LWD increased during recent decades, consistent with trends towards an earlier melt onset."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on June 13, 2016, 09:33:12 PM
The linked reference uses CMIP5 RCP 8.5 projections to confirm that Arctic sea-ice concentration, SIC, loss serves as feedback mechanism for Arctic Amplification, with conclusions including: "In these models, the AA trend tends to increase until the mean SIC reaches a critical level (i.e., 20 ~ 30%), and the maximum AA trend is almost three to five times larger than the trend in the early stage of global warming (i.e., 50 ~ 60%, 60 ~ 70%). However, the AA trend tends to decrease after that."

Bo Young Yim, Hong Sik Min, Baek-Min Kim, Jee-Hoon Jeong & Jong-Seong Kug (11 June 2016), "Sensitivity of Arctic warming to sea-ice concentration", JGR Atmospheres, DOI: 10.1002/2015JD023953

http://onlinelibrary.wiley.com/doi/10.1002/2015JD023953/abstract (http://onlinelibrary.wiley.com/doi/10.1002/2015JD023953/abstract)

Abstract: "We examine the sensitivity of Arctic amplification (AA) to background sea-ice concentration (SIC) under greenhouse warming by analyzing the datasets of the historical and Representative Concentration Pathway 8.5 (RCP8.5) runs of the Coupled Model Intercomparison Project Phase 5 (CMIP5). To determine whether the sensitivity of AA for a given radiative forcing depends on background SIC state, we examine the relationship between the AA trend and mean SIC on moving 30-yr windows from 1960 to 2100. It is found that the annual mean AA trend varies depending on the mean SIC condition. In particular, some models show a highly variable AA trend in relation to the mean SIC clearly. In these models, the AA trend tends to increase until the mean SIC reaches a critical level (i.e., 20 ~ 30%), and the maximum AA trend is almost three to five times larger than the trend in the early stage of global warming (i.e., 50 ~ 60%, 60 ~ 70%). However, the AA trend tends to decrease after that. Further analysis shows that the sensitivity of AA trend to mean SIC condition is closely related to the feedback processes associated with summer surface albedo and winter turbulent heat flux in the Arctic Ocean."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on June 13, 2016, 09:50:23 PM
The linked research discusses some recent efforts (& challenges) to try to better constraint the "… extremely large spread of effective climate sensitivity (ECS) ranging about 2.1–10.4 K":

Youichi Kamae, Hideo Shiogama, Masahiro Watanabe, Tomoo Ogura, Tokuta Yokohata, and Masahide Kimoto (6 June, 2016), "Lower tropospheric mixing as a constraint on cloud feedback in a Multi-Parameter Multi-Physics Ensemble", JCLI, DOI: http://dx.doi.org/10.1175/JCLI-D-16-0042.1 (http://dx.doi.org/10.1175/JCLI-D-16-0042.1)


http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-16-0042.1 (http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-16-0042.1)

Abstract: "Factors and possible constraints to extremely large spread of effective climate sensitivity (ECS) ranging about 2.1–10.4 K are examined by using a large-member ensemble of quadrupling CO2 experiments with an atmospheric general circulation model (AGCM). The ensemble, called Multi-Parameter Multi-Physics Ensemble (MPMPE), consists of both parametric and structural uncertainties in parameterizations of cloud, cumulus convection and turbulence based on two different versions of AGCM. Sum of low- and middle-cloud shortwave feedback explains most part of the ECS spread among the MPMPE members. Among half of perturbed physics ensembles (PPEs) in the MPMPE, variation in lower-tropospheric mixing intensity (LTMI) corresponds well with the ECS variation, while does not apply to the remainders. In the latter PPEs, large spread in optically-thick middle-cloud feedback over the equatorial ocean substantially affects the ECS, disrupts the LTMI–ECS relationship. Although observed LTMI can constrain uncertainty in the low-cloud feedback, total uncertainty of the ECS among the MPMPE cannot solely be explained by the LTMI, suggesting a limitation of single emergent constraint for the ECS."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on June 13, 2016, 10:00:57 PM
The linked research uses computer simulations of the Last Interglacial, LIG, to evaluate the sensitivity of global warming to changes in the Greenland Ice Sheet, GIS:

Pfeiffer, M. and Lohmann, G.: Greenland Ice Sheet influence on Last Interglacial climate: global sensitivity studies performed with an atmosphere–ocean general circulation model, Clim. Past, 12, 1313-1338, doi:10.5194/cp-12-1313-2016, 2016.

http://www.clim-past.net/12/1313/2016/ (http://www.clim-past.net/12/1313/2016/)

Abstract. During the Last Interglacial (LIG, ∼130–115 kiloyears (kyr) before present (BP)), the northern high latitudes were characterized by higher temperatures than those of the late Holocene and a lower Greenland Ice Sheet (GIS). However, the impact of a reduced GIS on the global climate has not yet been well constrained. In this study, we quantify the contribution of the GIS to LIG warmth by performing various sensitivity studies based on equilibrium simulations, employing the Community Earth System Models (COSMOS), with a focus on height and extent of the GIS. We present the first study on the effects of a reduction in the GIS on the surface temperature (TS) on a global scale and separate the contribution of astronomical forcing and changes in GIS to LIG warmth. The strong Northern Hemisphere summer warming of approximately 2 °C (with respect to pre-industrial) is mainly caused by increased summer insolation. Reducing the height by  ∼ 1300 m and the extent of the GIS does not have a strong influence during summer, leading to an additional global warming of only +0.24 °C compared to the purely insolation-driven LIG. The effect of a reduction in the GIS is, however, strongest during local winter, with up to +5 °C regional warming and with an increase in global average temperature of +0.48 °C.

In order to evaluate the performance of our LIG simulations, we additionally compare the simulated TS anomalies with marine and terrestrial proxy-based LIG temperature anomalies derived from three different proxy data compilations. Our model results are in good agreement with proxy records with respect to the warming pattern but underestimate the magnitude of temperature change when compared to reconstructions, suggesting a potential misinterpretation of the proxy records or deficits in our model. However, we are able to partly reduce the mismatch between model and data by additionally taking into account the potential seasonal bias of the proxy record and/or the uncertainties in the dating of the proxy records for the LIG thermal maximum. The seasonal bias and the uncertainty of the timing are estimated from new transient model simulations covering the whole LIG. The model–data comparison improves for proxies that represent annual mean temperatures when the GIS is reduced and when we take the local thermal maximum during the LIG (130–120 kyr BP) into account. For proxy data that represent summer temperatures, changes in the GIS are of minor importance for sea surface temperatures. However, the annual mean and summer temperature change over Greenland in the reduced GIS simulations seems to be overestimated as compared to the local ice core data, which could be related to the interpretation of the recorder system and/or the assumptions of GIS reduction. Thus, the question regarding the real size of the GIS during the LIG has yet to be answered.
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on June 18, 2016, 05:50:10 PM
Lightning flashes are projected to increase with continued global warming & the linked reference indicates that this will result in a change in the ozone distribution in the upper atmosphere, which in turn will change future climate change model projections (once they adopt the appropriate lightning parametrization.

Finney, D. L., Doherty, R. M., Wild, O., and Abraham, N. L.: The impact of lightning on tropospheric ozone chemistry using a new global lightning parametrisation, Atmos. Chem. Phys., 16, 7507-7522, doi:10.5194/acp-16-7507-2016, 2016.

http://www.atmos-chem-phys.net/16/7507/2016/ (http://www.atmos-chem-phys.net/16/7507/2016/)

Abstract. A lightning parametrisation based on upward cloud ice flux is implemented in a chemistry–climate model (CCM) for the first time. The UK Chemistry and Aerosols model is used to study the impact of these lightning nitric oxide (NO) emissions on ozone. Comparisons are then made between the new ice flux parametrisation and the commonly used, cloud-top height parametrisation. The ice flux approach improves the simulation of lightning and the temporal correlations with ozone sonde measurements in the middle and upper troposphere. Peak values of ozone in these regions are attributed to high lightning NO emissions. The ice flux approach reduces the overestimation of tropical lightning apparent in this CCM when using the cloud-top approach. This results in less NO emission in the tropical upper troposphere and more in the extratropics when using the ice flux scheme. In the tropical upper troposphere the reduction in ozone concentration is around 5–10 %. Surprisingly, there is only a small reduction in tropospheric ozone burden when using the ice flux approach. The greatest absolute change in ozone burden is found in the lower stratosphere, suggesting that much of the ozone produced in the upper troposphere is transported to higher altitudes. Major differences in the frequency distribution of flash rates for the two approaches are found. The cloud-top height scheme has lower maximum flash rates and more mid-range flash rates than the ice flux scheme. The initial Ox (odd oxygen species) production associated with the frequency distribution of continental lightning is analysed to show that higher flash rates are less efficient at producing Ox; low flash rates initially produce around 10 times more Ox per flash than high-end flash rates. We find that the newly implemented lightning scheme performs favourably compared to the cloud-top scheme with respect to simulation of lightning and tropospheric ozone. This alternative lightning scheme shows spatial and temporal differences in ozone chemistry which may have implications for comparison between models and observations, as well as for simulation of future changes in tropospheric ozone.

Edit: I note that increasing concentrations of ozone in the atmosphere will increase the near future GWP of methane.
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on June 24, 2016, 05:44:28 PM
The linked article is entitled: "Adapting Weather Forecasting Techniques to Paleoclimate Studies", and an improvement in understanding paleoclimate should eventually lead to improved model forecasts:


https://eos.org/research-spotlights/adapting-weather-forecasting-techniques-to-paleoclimate-studies

Extract: "First results of the Last Millennium Climate Reanalysis Project demonstrate the potential of the method to improve historical climate estimates by linking proxy data with climate models."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on June 30, 2016, 12:10:32 AM
As ACME is scheduled to start production runs beginning next month, I thought that it would be useful to link the pdf for the October 21–22, 2015 Workshop report entitled: "Accelerated Climate Modeling for Energy (ACME) – Atmospheric Radiation Measurement (ARM) Climate Research Facility – Atmospheric System Research (ASR) Coordination Workshop":


http://science.energy.gov/~/media/ber/pdf/workshop%20reports/CESD_ACME_ARM_ASR_workshopreport_web.pdf (http://science.energy.gov/~/media/ber/pdf/workshop%20reports/CESD_ACME_ARM_ASR_workshopreport_web.pdf)

See also:
http://asr.science.energy.gov/science/ (http://asr.science.energy.gov/science/)

Edit: Also the linked PowerPoint presentation entitled: "Land-Ice and Atmospheric Modeling at Sandia: the Albany/FELIX and Aeras Solvers" is associated with the ACME project:

http://slideplayer.com/slide/9165307/ (http://slideplayer.com/slide/9165307/)

Edit2: "For a video of preliminary model results (released in Dec 2015) see also:

https://vimeo.com/145875477 (https://vimeo.com/145875477)

Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on June 30, 2016, 11:04:31 PM
The linked reference on documenting human-induced greening of northern extratropical land surfaces will be valuable in calibrating state-of-the-art ESM projections, such as those to come from ACME:

Jiafu Mao, Aurélien Ribes, Binyan Yan, Xiaoying Shi, Peter E. Thornton, Roland Séférian, Philippe Ciais, Ranga B. Myneni, Hervé Douville, Shilong Piao, Zaichun Zhu, Robert E. Dickinson, Yongjiu Dai, Daniel M. Ricciuto, Mingzhou Jin, Forrest M. Hoffman, Bin Wang, Mengtian Huang & Xu Lian (2016), "Human-induced greening of the northern extratropical land surface", Nature Climate Change, doi:10.1038/nclimate3056


http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate3056.html (http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate3056.html)


Abstract: "Significant land greening in the northern extratropical latitudes (NEL) has been documented through satellite observations during the past three decades. This enhanced vegetation growth has broad implications for surface energy, water and carbon budgets, and ecosystem services across multiple scales. Discernible human impacts on the Earth’s climate system have been revealed by using statistical frameworks of detection–attribution. These impacts, however, were not previously identified on the NEL greening signal, owing to the lack of long-term observational records, possible bias of satellite data, different algorithms used to calculate vegetation greenness, and the lack of suitable simulations from coupled Earth system models (ESMs). Here we have overcome these challenges to attribute recent changes in NEL vegetation activity. We used two 30-year-long remote-sensing-based leaf area index (LAI) data sets, simulations from 19 coupled ESMs with interactive vegetation, and a formal detection and attribution algorithm. Our findings reveal that the observed greening record is consistent with an assumption of anthropogenic forcings, where greenhouse gases play a dominant role, but is not consistent with simulations that include only natural forcings and internal climate variability. These results provide the first clear evidence of a discernible human fingerprint on physiological vegetation changes other than phenology and range shifts."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on July 06, 2016, 11:48:38 PM
The linked reference indicates that climate change Integrated Assessment Models need to include cross-sectoral interactions:

Paula A. Harrison, Robert W. Dunford, Ian P. Holman & Mark D. A. Rounsevell (2016), "Climate change impact modelling needs to include cross-sectoral interactions", Nature Climate Change, doi:10.1038/nclimate3039


http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate3039.html (http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate3039.html)

Abstract: "Climate change impact assessments often apply models of individual sectors such as agriculture, forestry and water use without considering interactions between these sectors. This is likely to lead to misrepresentation of impacts, and consequently to poor decisions about climate adaptation. However, no published research assesses the differences between impacts simulated by single-sector and integrated models. Here we compare 14 indicators derived from a set of impact models run within single-sector and integrated frameworks across a range of climate and socio-economic scenarios in Europe. We show that single-sector studies misrepresent the spatial pattern, direction and magnitude of most impacts because they omit the complex interdependencies within human and environmental systems. The discrepancies are particularly pronounced for indicators such as food production and water exploitation, which are highly influenced by other sectors through changes in demand, land suitability and resource competition. Furthermore, the discrepancies are greater under different socio-economic scenarios than different climate scenarios, and at the sub-regional rather than Europe-wide scale."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on July 13, 2016, 12:33:04 AM
The linked reference discusses modeling efforts towards quantifying the economic cost associated with climatic "tipping points".  While the reference has some value it discounts the risk of a WAIS collapse this century by noting that most climate change models cannot account for cliff failures and hydrofracturing, and proceeds to base its findings on models that are incapable of matching the DeConto & Pollard (2016) findings that the WAIS could collapse before the GMST departure reaches 2.7C above pre-industrial levels:

Robert E. Kopp, Rachael Shwom, Gernot Wagner & Jiacan Yuan (2016), "Tipping elements and climate-economic shocks: Pathways toward integrated assessment", Earth's Future, DOI: 10.1002/2016EF000362.
 
http://onlinelibrary.wiley.com/doi/10.1002/2016EF000362/abstract (http://onlinelibrary.wiley.com/doi/10.1002/2016EF000362/abstract)
&
http://onlinelibrary.wiley.com/doi/10.1002/2016EF000362/epdf (http://onlinelibrary.wiley.com/doi/10.1002/2016EF000362/epdf)

Abstract: "The literature on the costs of climate change often draws a link between climatic ‘tipping points’ and large economic shocks, frequently called ‘catastrophes’. The phrase ‘tipping points’ in this context can be misleading. In popular and social scientific discourse, ‘tipping points’ involve abrupt state changes. For some climatic ‘tipping points,’ the commitment to a state change may occur abruptly, but the change itself may be rate-limited and take centuries or longer to realize. Additionally, the connection between climatic ‘tipping points’ and economic losses is tenuous, though emerging empirical and process-model-based tools provide pathways for investigating it. We propose terminology to clarify the distinction between ‘tipping points’ in the popular sense, the critical thresholds exhibited by climatic and social ‘tipping elements,’ and ‘economic shocks’. The last may be associated with tipping elements, gradual climate change, or non-climatic triggers. We illustrate our proposed distinctions by surveying the literature on climatic tipping elements, climatically sensitive social tipping elements, and climate-economic shocks, and we propose a research agenda to advance the integrated assessment of all three."

Extract: "… most ice sheet models do not include ice cliff collapse and hydrofracturing, which destabilize ice shelves and may greatly increase the rate of ice sheet mass loss [Pollard et al., 2015; DeConto and Pollard, 2016]."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on July 25, 2016, 08:27:30 PM
Improvements (as cited in the linked reference) for integrated assessment models is sorely needed; however, I am concerned that such efforts will simply ignore Hansen's ice-climate feedback mechanism as being too abrupt for them to address.  Thus I suspect that there will likely be very little advance notice for such a climate hazard (especially with regard to the possibility of the WAIS beginning to collapse this century).

Robert E. Kopp, Rachael Shwom, Gernot Wagner, Jiacan Yuan. Tipping elements and climate-economic shocks: Pathways toward integrated assessment. Earth's Future, 2016; DOI: 10.1002/2016EF000362

http://onlinelibrary.wiley.com/doi/10.1002/2016EF000362/abstract?systemMessage=Wiley+Online+Library+will+be+unavailable+on+Saturday+30th+July+2016+from+08:00-11:00+BST+/+03:00-06:00+EST+/+15:00-18:00+SGT+for+essential+maintenance.Apologies+for+the+inconvenience. (http://onlinelibrary.wiley.com/doi/10.1002/2016EF000362/abstract?systemMessage=Wiley+Online+Library+will+be+unavailable+on+Saturday+30th+July+2016+from+08:00-11:00+BST+/+03:00-06:00+EST+/+15:00-18:00+SGT+for+essential+maintenance.Apologies+for+the+inconvenience.)

Abstract: "The literature on the costs of climate change often draws a link between climatic ‘tipping points’ and large economic shocks, frequently called ‘catastrophes’. The phrase ‘tipping points’ in this context can be misleading. In popular and social scientific discourse, ‘tipping points’ involve abrupt state changes. For some climatic ‘tipping points,’ the commitment to a state change may occur abruptly, but the change itself may be rate-limited and take centuries or longer to realize. Additionally, the connection between climatic ‘tipping points’ and economic losses is tenuous, though emerging empirical and process-model-based tools provide pathways for investigating it. We propose terminology to clarify the distinction between ‘tipping points’ in the popular sense, the critical thresholds exhibited by climatic and social ‘tipping elements,’ and ‘economic shocks’. The last may be associated with tipping elements, gradual climate change, or non-climatic triggers. We illustrate our proposed distinctions by surveying the literature on climatic tipping elements, climatically sensitive social tipping elements, and climate-economic shocks, and we propose a research agenda to advance the integrated assessment of all three."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on July 25, 2016, 10:14:16 PM
The linked (open access) reference discusses CMIP6, which will run through 2020 per the attached image.  As a side note, it is my personal opinion that frequently the authors of the reference tend to err on the side of least drama:

Eyring, V., Bony, S., Meehl, G. A., Senior, C. A., Stevens, B., Stouffer, R. J., and Taylor, K. E.: Overview of the Coupled Model Intercomparison Project Phase 6 (CMIP6) experimental design and organization, Geosci. Model Dev., 9, 1937-1958, doi:10.5194/gmd-9-1937-2016, 2016

http://www.geosci-model-dev.net/9/1937/2016/gmd-9-1937-2016.pdf (http://www.geosci-model-dev.net/9/1937/2016/gmd-9-1937-2016.pdf)

Abstract: "By coordinating the design and distribution of global climate model simulations of the past, current, and future climate, the Coupled Model Intercomparison Project (CMIP) has become one of the foundational elements of climate science. However, the need to address an ever-expanding range of scientific questions arising from more and more research communities has made it necessary to revise the organization of CMIP. After a long and wide community consultation, a new and more federated structure has been put in place. It consists of three major elements: (1) a handful of common experiments, the DECK (Diagnostic, Evaluation and Characterization of Klima) and CMIP historical simulations (1850–near present) that will maintain continuity and help document basic characteristics of models across different phases of CMIP; (2) common standards, coordination, infrastructure, and documentation that will facilitate the distribution of model outputs and the characterization of the model ensemble; and (3) an ensemble of CMIP-Endorsed Model Intercomparison Projects (MIPs) that will be specific to a particular phase of CMIP (now CMIP6) and that will build on the DECK and CMIP historical simulations to address a large range of specific questions and fill the scientific gaps of the previous CMIP phases. The DECK and CMIP historical simulations, together with the use of CMIP data standards, will be the entry cards for models participating in CMIP. Participation in CMIP6-Endorsed MIPs by individual modelling groups will be at their own discretion and will depend on their scientific interests and priorities. With the Grand Science Challenges of the World Climate Research Programme (WCRP) as its scientific backdrop, CMIP6 will address three broad questions:

– How does the Earth system respond to forcing?

– What are the origins and consequences of systematic model biases?

– How can we assess future climate changes given internal climate variability, predictability, and uncertainties in scenarios?

This CMIP6 overview paper presents the background and rationale for the new structure of CMIP, provides a detailed description of the DECK and CMIP6 historical simulations, and includes a brief introduction to the 21 CMIP6-Endorsed MIPs."

See also:

http://www.wcrp-climate.org/index.php/wgcm-cmip/wgcm-cmip6 (http://www.wcrp-climate.org/index.php/wgcm-cmip/wgcm-cmip6)
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on July 26, 2016, 01:01:39 AM
The linked research indicates that future integrate assessment model projections should include the impact of armed-conflict triggered by climate-related disasters:

Carl-Friedrich Schleussner, Jonathan F. Donges, Reik V. Donner and Hans Joachim Schellnhuber (July 25, 2016), "Armed-conflict risks enhanced by climate-related disasters in ethnically fractionalized countries", PNAS, doi: 10.1073/pnas.1601611113

http://www.pnas.org/content/early/2016/07/20/1601611113 (http://www.pnas.org/content/early/2016/07/20/1601611113)

Significance: "Ethnic divides play a major role in many armed conflicts around the world and might serve as predetermined conflict lines following rapidly emerging societal tensions arising from disruptive events like natural disasters. We find evidence in global datasets that risk of armed-conflict outbreak is enhanced by climate-related disaster occurrence in ethnically fractionalized countries. Although we find no indications that environmental disasters directly trigger armed conflicts, our results imply that disasters might act as a threat multiplier in several of the world’s most conflict-prone regions."

Abstract: "Social and political tensions keep on fueling armed conflicts around the world. Although each conflict is the result of an individual context-specific mixture of interconnected factors, ethnicity appears to play a prominent and almost ubiquitous role in many of them. This overall state of affairs is likely to be exacerbated by anthropogenic climate change and in particular climate-related natural disasters. Ethnic divides might serve as predetermined conflict lines in case of rapidly emerging societal tensions arising from disruptive events like natural disasters. Here, we hypothesize that climate-related disaster occurrence enhances armed-conflict outbreak risk in ethnically fractionalized countries. Using event coincidence analysis, we test this hypothesis based on data on armed-conflict outbreaks and climate-related natural disasters for the period 1980–2010. Globally, we find a coincidence rate of 9% regarding armed-conflict outbreak and disaster occurrence such as heat waves or droughts. Our analysis also reveals that, during the period in question, about 23% of conflict outbreaks in ethnically highly fractionalized countries robustly coincide with climatic calamities. Although we do not report evidence that climate-related disasters act as direct triggers of armed conflicts, the disruptive nature of these events seems to play out in ethnically fractionalized societies in a particularly tragic way. This observation has important implications for future security policies as several of the world’s most conflict-prone regions, including North and Central Africa as well as Central Asia, are both exceptionally vulnerable to anthropogenic climate change and characterized by deep ethnic divides."


See also:
https://www.theguardian.com/environment/2016/jul/25/disasters-linked-to-climate-can-increase-risk-of-armed-conflict (https://www.theguardian.com/environment/2016/jul/25/disasters-linked-to-climate-can-increase-risk-of-armed-conflict)

Extract: "Research found that 23% of violent clashes in ethnically divided places were connected to climate disasters"

&
https://www.washingtonpost.com/news/energy-environment/wp/2016/07/25/how-climate-disasters-can-drive-violent-conflict-around-the-world/ (https://www.washingtonpost.com/news/energy-environment/wp/2016/07/25/how-climate-disasters-can-drive-violent-conflict-around-the-world/)

Extract: "It’s increasingly clear that the consequences of climate change won’t stop at just heat waves and sea-level rise. Scientists expect numerous social issues to arise around the world as well, such as food shortages, decreased water quality and forced migrations. And many experts now say that violence, war and other forms of human conflict may be driven or worsened by the effects of climate change."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on August 09, 2016, 07:36:47 PM
Many people become confused by the dynamics of energy flux and regional temperature changes due to AGW; and the linked reference provides insights (using an energy balance decomposition of temperature changes for CMIP5) including:
"The three most important terms for intermodel differences in warming are the changes in the clear-sky greenhouse effect, clouds, and the net surface energy flux, making the largest contribution to the standard deviation of annual mean temperature change in 34, 29 and 20 % of the world, respectively. Changes in atmospheric energy flux convergence mostly damp intermodel variations of temperature change especially over the oceans. However, the opposite is true for example in Greenland and Antarctica, where the warming appears to be substantially controlled by heat transport from the surrounding sea areas."
Jouni Räisänen (06 August 2016), "An energy balance perspective on regional CO2-induced temperature changes in CMIP5 models", Climate Dynamics, pp 1-14, DOI: 10.1007/s00382-016-3277-2

http://rd.springer.com/article/10.1007%2Fs00382-016-3277-2 (http://rd.springer.com/article/10.1007%2Fs00382-016-3277-2)

Abstract: "An energy balance decomposition of temperature changes is conducted for idealized transient CO2-only simulations in the fifth phase of the Coupled Model Intercomparison Project. The multimodel global mean warming is dominated by enhanced clear-sky greenhouse effect due to increased CO2 and water vapour, but other components of the energy balance substantially modify the geographical and seasonal patterns of the change. Changes in the net surface energy flux are important over the oceans, being especially crucial for the muted warming over the northern North Atlantic and for the seasonal cycle of warming over the Arctic Ocean. Changes in atmospheric energy flux convergence tend to smooth the gradients of temperature change and reduce its land-sea contrast, but they also amplify the seasonal cycle of warming in northern North America and Eurasia. The three most important terms for intermodel differences in warming are the changes in the clear-sky greenhouse effect, clouds, and the net surface energy flux, making the largest contribution to the standard deviation of annual mean temperature change in 34, 29 and 20 % of the world, respectively. Changes in atmospheric energy flux convergence mostly damp intermodel variations of temperature change especially over the oceans. However, the opposite is true for example in Greenland and Antarctica, where the warming appears to be substantially controlled by heat transport from the surrounding sea areas."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on August 16, 2016, 08:33:13 PM
The two linked Nature Geoscience references respectively discuss the influence of the IPO, and the NAO, (both superimposed on Anthropogenic forcing) on Earth Systems.  Hopefully, findings from such research will improve future climate change model forecasts:

Yu Kosaka & Shang-Ping Xie (2016), "The tropical Pacific as a key pacemaker of the variable rates of global warming", Nature Geoscience, doi:10.1038/ngeo2770

http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo2770.html (http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo2770.html)

Abstract: "Global mean surface temperature change over the past 120 years resembles a rising staircase: the overall warming trend was interrupted by the mid-twentieth-century big hiatus and the warming slowdown since about 1998. The Interdecadal Pacific Oscillation has been implicated in modulations of global mean surface temperatures, but which part of the mode drives the variability in warming rates is unclear. Here we present a successful simulation of the global warming staircase since 1900 with a global ocean–atmosphere coupled model where tropical Pacific sea surface temperatures are forced to follow the observed evolution. Without prescribed tropical Pacific variability, the same model, on average, produces a continual warming trend that accelerates after the 1960s. We identify four events where the tropical Pacific decadal cooling markedly slowed down the warming trend. Matching the observed spatial and seasonal fingerprints we identify the tropical Pacific as a key pacemaker of the warming staircase, with radiative forcing driving the overall warming trend. Specifically, tropical Pacific variability amplifies the first warming epoch of the 1910s–1940s and determines the timing when the big hiatus starts and ends. Our method of removing internal variability from the observed record can be used for real-time monitoring of anthropogenic warming."


&


Thomas L. Delworth, Fanrong Zeng, Gabriel A. Vecchi, Xiaosong Yang, Liping Zhang & Rong Zhang (2016), "The North Atlantic Oscillation as a driver of rapid climate change in the Northern Hemisphere", Nature Geoscience, Volume: 9, Pages: 509–512, doi:10.1038/ngeo2738

http://www.nature.com/ngeo/journal/v9/n7/full/ngeo2738.html (http://www.nature.com/ngeo/journal/v9/n7/full/ngeo2738.html)

Abstract: "Pronounced climate changes have occurred since the 1970s, including rapid loss of Arctic sea ice, large-scale warming and increased tropical storm activity in the Atlantic. Anthropogenic radiative forcing is likely to have played a major role in these changes, but the relative influence of anthropogenic forcing and natural variability is not well established. The above changes have also occurred during a period in which the North Atlantic Oscillation has shown marked multidecadal variations. Here we investigate the role of the North Atlantic Oscillation in these rapid changes through its influence on the Atlantic meridional overturning circulation and ocean heat transport. We use climate models to show that observed multidecadal variations of the North Atlantic Oscillation can induce multidecadal variations in the Atlantic meridional overturning circulation and poleward ocean heat transport in the Atlantic, extending to the Arctic. Our results suggest that these variations have contributed to the rapid loss of Arctic sea ice, Northern Hemisphere warming, and changing Atlantic tropical storm activity, especially in the late 1990s and early 2000s. These multidecadal variations are superimposed on long-term anthropogenic forcing trends that are the dominant factor in long-term Arctic sea ice loss and hemispheric warming."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on August 19, 2016, 06:22:55 PM
The linked reference identifies the occurrence of atmospheric rivers extending from the Maritime Continent to the Bering Strait as one factor contributing to Arctic Amplification.  Hopefully, CMIP6 will use such findings to better calibrate their model runs so that AR6 will account for (rather than ignore) this positive feedback mechanism:

Cory Baggett, Sukyoung Lee & Steven Feldstein (12 August 2016), "An investigation of the presence of atmospheric rivers over the North Pacific during planetary-scale wave life cycles and their role in Arctic warming", Journal of the Atmospheric Sciences, DOI: http://dx.doi.org/10.1175/JAS-D-16-0033.1 (http://dx.doi.org/10.1175/JAS-D-16-0033.1)

http://journals.ametsoc.org/doi/abs/10.1175/JAS-D-16-0033.1 (http://journals.ametsoc.org/doi/abs/10.1175/JAS-D-16-0033.1)

Abstract: "Heretofore, the Tropically Excited Arctic warMing mechanism (TEAM) put forward that localized tropical convection amplifies planetary-scale waves which transport sensible and latent heat into the Arctic – leading to an enhancement of downward infrared radiation and Arctic surface warming. In this study, an investigation is made into the previously unexplored contribution of the synoptic-scale waves and their attendant atmospheric rivers to the TEAM mechanism.
Reanalysis data is used to conduct a suite of observational analyses, trajectory calculations, and idealized model simulations. It is shown that localized tropical convection over the Maritime Continent precedes the peak of the planetary-scale wave life cycle by ~10 to 14 days. The Rossby wave source induced by the tropical convection excites a Rossby wave train over the North Pacific that amplifies the climatological December-March stationary waves. These amplified planetary-scale waves are baroclinic and transport sensible and latent heat poleward. During the planetary-scale wave life cycle, synoptic-scale waves are diverted northward over the central North Pacific. The warm conveyor belts associated with the synoptic-scale waves channel moisture from the subtropics into atmospheric rivers which ascend as they move poleward and penetrate into the Arctic near the Bering Strait. At this time, the synoptic-scale waves undergo cyclonic Rossby wave breaking which further amplifies the planetary-scale waves. The planetary-scale wave life cycle ceases as ridging over Alaska retrogrades westward. The ridging blocks additional moisture transport into the Arctic. However, sensible and latent heat remain elevated over the Arctic which enhances downward infrared radiation and maintains warm surface temperatures."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on August 25, 2016, 10:17:57 AM
The GMD now has a special issue devoted to CMIP6:

Coupled Model Intercomparison Project Phase 6 (CMIP6) Experimental Design and Organization
Editor(s): GMD topical editors | Coordinator: V. Eyring

http://www.geosci-model-dev.net/special_issue590.html (http://www.geosci-model-dev.net/special_issue590.html)
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on September 22, 2016, 09:44:52 PM
The linked (open access) three part reference provides information about the "The Zugspitze radiative closure experiment for quantifying water vapor absorption over the terrestrial and solar infrared".  Such information is important for calibrating Earth System Models:

Sussmann, R., Reichert, A., and Rettinger, M.: The Zugspitze radiative closure experiment for quantifying water vapor absorption over the terrestrial and solar infrared – Part 1: Setup, uncertainty analysis, and assessment of far-infrared water vapor continuum, Atmos. Chem. Phys., 16, 11649-11669, doi:10.5194/acp-16-11649-2016, 2016.

http://www.atmos-chem-phys.net/16/11649/2016/ (http://www.atmos-chem-phys.net/16/11649/2016/)

Abstract. Quantitative knowledge of water vapor radiative processes in the atmosphere throughout the terrestrial and solar infrared spectrum is still incomplete even though this is crucial input to the radiation codes forming the core of both remote sensing methods and climate simulations. Beside laboratory spectroscopy, ground-based remote sensing field studies in the context of so-called radiative closure experiments are a powerful approach because this is the only way to quantify water absorption under cold atmospheric conditions. For this purpose, we have set up at the Zugspitze (47.42° N, 10.98° E; 2964 m a.s.l.) a long-term radiative closure experiment designed to cover the infrared spectrum between 400 and 7800 cm−1 (1.28–25 µm). As a benefit for such experiments, the atmospheric states at the Zugspitze frequently comprise very low integrated water vapor (IWV; minimum  =  0.1 mm, median  =  2.3 mm) and very low aerosol optical depth (AOD  =  0.0024–0.0032 at 7800 cm−1 at air mass 1). All instruments for radiance measurements and atmospheric-state measurements are described along with their measurement uncertainties. Based on all parameter uncertainties and the corresponding radiance Jacobians, a systematic residual radiance uncertainty budget has been set up to characterize the sensitivity of the radiative closure over the whole infrared spectral range. The dominant uncertainty contribution in the spectral windows used for far-infrared (FIR) continuum quantification is from IWV uncertainties, while T profile uncertainties dominate in the mid-infrared (MIR). Uncertainty contributions to near-infrared (NIR) radiance residuals are dominated by water vapor line parameters in the vicinity of the strong water vapor bands. The window regions in between these bands are dominated by solar Fourier transform infrared (FTIR) calibration uncertainties at low NIR wavenumbers, while uncertainties due to AOD become an increasing and dominant contribution towards higher NIR wavenumbers. Exceptions are methane or nitrous oxide bands in the NIR, where the associated line parameter uncertainties dominate the overall uncertainty.

As a first demonstration of the Zugspitze closure experiment, a water vapor continuum quantification in the FIR spectral region (400–580 cm−1) has been performed. The resulting FIR foreign-continuum coefficients are consistent with the MT_CKD 2.5.2 continuum model and also agree with the most recent atmospheric closure study carried out in Antarctica. Results from the first determination of the NIR water vapor continuum in a field experiment are detailed in a companion paper (Reichert and Sussmann, 2016) while a novel NIR calibration scheme for the underlying FTIR measurements of incoming solar radiance is presented in another companion paper (Reichert et al., 2016).




Reichert, A., Rettinger, M., and Sussmann, R.: The Zugspitze radiative closure experiment for quantifying water vapor absorption over the terrestrial and solar infrared – Part 2: Accurate calibration of high spectral-resolution infrared measurements of surface solar radiation, Atmos. Meas. Tech., 9, 4673-4686, doi:10.5194/amt-9-4673-2016, 2016.
http://www.atmos-meas-tech.net/9/4673/2016/ (http://www.atmos-meas-tech.net/9/4673/2016/)

Abstract. Quantitative knowledge of water vapor absorption is crucial for accurate climate simulations. An open science question in this context concerns the strength of the water vapor continuum in the near infrared (NIR) at atmospheric temperatures, which is still to be quantified by measurements. This issue can be addressed with radiative closure experiments using solar absorption spectra. However, the spectra used for water vapor continuum quantification have to be radiometrically calibrated. We present for the first time a method that yields sufficient calibration accuracy for NIR water vapor continuum quantification in an atmospheric closure experiment. Our method combines the Langley method with spectral radiance measurements of a high-temperature blackbody calibration source (<  2000 K). The calibration scheme is demonstrated in the spectral range 2500 to 7800 cm−1, but minor modifications to the method enable calibration also throughout the remainder of the NIR spectral range. The resulting uncertainty (2σ) excluding the contribution due to inaccuracies in the extra-atmospheric solar spectrum (ESS) is below 1 % in window regions and up to 1.7 % within absorption bands. The overall radiometric accuracy of the calibration depends on the ESS uncertainty, on which at present no firm consensus has been reached in the NIR. However, as is shown in the companion publication Reichert and Sussmann (2016), ESS uncertainty is only of minor importance for the specific aim of this study, i.e., the quantification of the water vapor continuum in a closure experiment. The calibration uncertainty estimate is substantiated by the investigation of calibration self-consistency, which yields compatible results within the estimated errors for 91.1 % of the 2500 to 7800 cm−1 range. Additionally, a comparison of a set of calibrated spectra to radiative transfer model calculations yields consistent results within the estimated errors for 97.7 % of the spectral range.


Reichert, A. and Sussmann, R.: The Zugspitze radiative closure experiment for quantifying water vapor absorption over the terrestrial and solar infrared – Part 3: Quantification of the mid- and near-infrared water vapor continuum in the 2500 to 7800 cm−1 spectral range under atmospheric conditions, Atmos. Chem. Phys., 16, 11671-11686, doi:10.5194/acp-16-11671-2016, 2016.

http://www.atmos-chem-phys.net/16/11671/2016/ (http://www.atmos-chem-phys.net/16/11671/2016/)

Abstract. We present a first quantification of the near-infrared (NIR) water vapor continuum absorption from an atmospheric radiative closure experiment carried out at the Zugspitze (47.42° N, 10.98° E; 2964 m a.s.l.). Continuum quantification is achieved via radiative closure using radiometrically calibrated solar Fourier transform infrared (FTIR) absorption spectra covering the 2500 to 7800 cm−1 spectral range. The dry atmospheric conditions at the Zugspitze site (IWV 1.4 to 3.3 mm) enable continuum quantification even within water vapor absorption bands, while upper limits for continuum absorption can be provided in the centers of window regions. Throughout 75 % of the 2500 to 7800 cm−1 spectral range, the Zugspitze results agree within our estimated uncertainty with the widely used MT_CKD 2.5.2 model (Mlawer et al., 2012). In the wings of water vapor absorption bands, our measurements indicate about 2–5 times stronger continuum absorption than MT_CKD, namely in the 2800 to 3000 cm−1 and 4100 to 4200 cm−1 spectral ranges. The measurements are consistent with the laboratory measurements of Mondelain et al. (2015), which rely on cavity ring-down spectroscopy (CDRS), and the calorimetric–interferometric measurements of Bicknell et al. (2006). Compared to the recent FTIR laboratory studies of Ptashnik et al. (2012, 2013), our measurements are consistent within the estimated errors throughout most of the spectral range. However, in the wings of water vapor absorption bands our measurements indicate typically 2–3 times weaker continuum absorption under atmospheric conditions, namely in the 3200 to 3400, 4050 to 4200, and 6950 to 7050 cm−1 spectral regions.
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on September 28, 2016, 05:52:30 PM
The devil is in the details, and the linked reference is entitled: "Characterizing And Understanding Systematic Biases In The Vertical Structure Of Clouds In CMIP5/CFMIP2 Models".  I suspect that when such systemic biases are corrected the net resulting contribution to feedback will be positive:

G. Cesana & D. E. Waliser (27 September 2016), "Characterizing And Understanding Systematic Biases In The Vertical Structure Of Clouds In CMIP5/CFMIP2 Models", Geophysical Research Letters, DOI: 10.1002/2016GL070515

http://onlinelibrary.wiley.com/doi/10.1002/2016GL070515/abstract (http://onlinelibrary.wiley.com/doi/10.1002/2016GL070515/abstract)

Abstract: "From a traditional low-, mid- and high-cloud “layered” perspective as well as a more detailed “level” perspective (40 levels), we compare the vertical distribution of clouds in twelve general circulation models (GCMs) against the GCM-Oriented Cloud-Aerosols Lidar and Infrared Pathfinder Satellite Observations Cloud Product (CALIPSO-GOCCP) using a satellite simulator approach. The “layered” perspective shows that models exhibit the similar regional biases: an overestimate (underestimate) of high-clouds over oceans (continents) in the tropics and a strong underestimate of low-clouds over stratocumulus regions. Although high-clouds are too infrequent on average, the “level” perspective reveals that high-level clouds fill too many upper levels of the column when present (geometrically too thick), suggesting an overestimation of the cloud overlap. Compositing by dynamical regimes and large-scale relative humidity shows that the models tend to have too many high-level clouds in moist environments, and too few boundary-layer clouds in dry environments regardless of dynamical regimes."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on September 30, 2016, 10:10:23 PM
The linked reference indicates that changes in extratropical clouds associated with a reduction in high latitude albedo can impact atmospheric heat transport via changes in the Hadley cell:

Nicole Feldl, Simona Bordoni & Timothy M. Merlis (September 28 2016), "Coupled high-latitude climate feedbacks and their impact on atmospheric heat transport", Journal of Climate, DOI: http://dx.doi.org/10.1175/JCLI-D-16-0324.1 (http://dx.doi.org/10.1175/JCLI-D-16-0324.1)


http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-16-0324.1 (http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-16-0324.1)

Abstract: "The response of atmospheric heat transport to anthropogenic warming is determined by the anomalous meridional energy gradient. Feedback analysis offers a characterization of that gradient and hence reveals how uncertainty in physical processes may translate into uncertainty in the circulation response. However, individual feedbacks do not act in isolation. Anomalies associated with one feedback may be compensated by another, as is the case for the positive water vapor and negative lapse rate feedbacks in the tropics. Here we perform a set of idealized experiments in an aquaplanet model to evaluate the coupling between the surface albedo feedback and other feedbacks, including the impact on atmospheric heat transport. In the tropics, the dynamical response manifests as changes in the intensity and structure of the overturning Hadley circulation. Only half of the range of Hadley cell weakening exhibited in these experiments is found to be attributable to imposed, systematic variations in the surface albedo feedback. Changes in extratropical clouds that accompany the albedo changes explain the remaining spread. The feedback-driven circulation changes are compensated by eddy energy flux changes, which reduce the overall spread among experiments. These findings have implications for the efficiency with which the climate system, including tropical circulation and the hydrological cycle, adjusts to high latitude feedbacks, over climate states that range from perennial or seasonal ice to ice-free conditions in the Arctic."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on October 03, 2016, 03:43:07 PM
The linked open access reference provides an excellent summary of cloud feedback processes and discusses means to further reduce uncertainties associated with this complex topic:

Gettelman, A. & Sherwood, S.C. (2016), "Processes Responsible for Cloud Feedback", Curr Clim Change Rep,  doi:10.1007/s40641-016-0052-8


http://rd.springer.com/article/10.1007%2Fs40641-016-0052-8?wt_mc=Affiliate.CommissionJunction.3.EPR1089.DeepLink (http://rd.springer.com/article/10.1007%2Fs40641-016-0052-8?wt_mc=Affiliate.CommissionJunction.3.EPR1089.DeepLink)

Abstract: "Cloud feedback on global climate is determined by the combined action of multiple processes that have different relevance in different cloud regimes. This review lays out the framework for cloud feedback and highlights recent advances and outstanding issues. A consensus is emerging on large-scale controls on cloud feedback. Recent work has made significant progress in the understanding and observationally constraining the local response of shallow clouds. But significant uncertainties remain in microphysical mechanisms for cloud feedback. Important microphysical mechanisms include cloud phase changes, precipitation processes and even aerosol distributions. The treatment of these processes varies across climate models and may contribute to greater spread in feedbacks across models as models advance. Future work will need to try to bound the range of possible cloud microphysical feedback mechanisms and seek observational constraints on them."

Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on October 13, 2016, 05:36:22 PM
The linked reference helps to quantify the role of cloud radiative heating with the atmosphere; which is not fully modeled in CMIP5; while this influence can of particular importance in regional areas like the Equatorial Pacific:

Bryce E. Harrop & Dennis L. Hartmann (31 August 2016), "The role of cloud radiative heating within the atmosphere on the high cloud amount and top-of-atmosphere cloud radiative effect", JAMES, DOI: 10.1002/2016MS000670


http://onlinelibrary.wiley.com/doi/10.1002/2016MS000670/full (http://onlinelibrary.wiley.com/doi/10.1002/2016MS000670/full)

Abstract: "The effect of cloud-radiation interactions on cloud properties is examined in the context of a limited-domain cloud-resolving model. The atmospheric cloud radiative effect (ACRE) influences the areal extent of tropical high clouds in two distinct ways. The first is through direct radiative destabilization of the elevated cloud layers, mostly as a result of longwave radiation heating the cloud bottom and cooling the cloud top. The second effect is radiative stabilization, whereby cloud radiative heating of the atmospheric column stabilizes the atmosphere to deep convection. In limited area domain simulations, the stabilizing (or indirect) effect is the dominant role of the cloud radiative heating, thus reducing the cloud cover in simulations where ACRE is included compared to those where it is removed. Direct cloud radiative heating increases high cloud fraction, decreases mean cloud optical depth, and increases cloud top temperature. The indirect cloud radiative heating decreases high cloud fraction, but also decreases mean cloud optical depth and increases cloud top temperature. The combination of these effects increases the top-of-atmosphere cloud radiative effect. In mock-Walker circulation experiments, the decrease in high cloud amount owing to radiative stabilization tends to cancel out the increase in high cloud amount owing to the destabilization within the cloud layer. The changes in cloud optical depth and cloud top pressure, however, are similar to those produced in the limited area domain simulations."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on October 13, 2016, 05:46:56 PM
The linked reference discuss how as atmospheric moisture increases cloud radiative cooling can decrease in an unstable fashion (particularly in the tropics).  This research indicates a need to update current climate models to adequately model this effect:

Tom Beucler & Timothy W. Cronin (11 October 2016), "Moisture-radiative cooling instability", JAMES, DOI: 10.1002/2016MS000763

http://onlinelibrary.wiley.com/doi/10.1002/2016MS000763/full (http://onlinelibrary.wiley.com/doi/10.1002/2016MS000763/full)

Abstract: "Radiative-convective equilibrium (RCE)—the statistical equilibrium state of the atmosphere where convection and radiation interact in the absence of lateral transport—is widely used as a basic-state model of the tropical atmosphere. The possibility that RCE may be unstable to development of large-scale circulation has been raised by recent modeling, theoretical, and observational studies, and could have profound consequences for our understanding of tropical meteorology and climate. Here, we study the interaction between moisture and radiative cooling as a contributor to instability of RCE. We focus on whether the total atmospheric radiative cooling decreases with column water vapor; this condition, which we call moisture-radiative cooling instability (MRCI), provides the potential for unstable growth of moist or dry perturbations. Analytic solutions to the gray-gas radiative transfer equations show that MRCI is satisfied when the total column optical depth—linked to column water vapor—exceeds a critical threshold. Both the threshold and the growth rate of the instability depend strongly on the shape of the water vapor perturbation. Calculations with a realistic radiative transfer model confirm the existence of MRCI for typical tropical values of column water vapor, but show even stronger dependence on the vertical structure of water vapor perturbation. Finally, we analyze the sensitivity of atmospheric radiative cooling to variability in column water vapor in observed tropical soundings. We find that clear-sky MRCI is satisfied across a range of locations and seasons in the real tropical atmosphere, with a partial growth rate of ∼1 month."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on October 17, 2016, 05:14:31 PM
It is my general feeling that so many climate change projections err on the side of least drama that it makes most risk assessments ineffective.  Nevertheless, I provide the following linked article that addresses how to build climate change risks into such assessments:

Coletti, A., De Nicola, A. & Villani, M.L. (2016), "Building climate change into risk assessments", Nat Hazards  84: 1307. doi:10.1007/s11069-016-2487-6


http://rd.springer.com/article/10.1007%2Fs11069-016-2487-6?wt_mc=Affiliate.CommissionJunction.3.EPR1089.DeepLink&utm_medium=affiliate&utm_source=commission_junction&utm_campaign=3_nsn6445_deeplink&utm_content=deeplink (http://rd.springer.com/article/10.1007%2Fs11069-016-2487-6?wt_mc=Affiliate.CommissionJunction.3.EPR1089.DeepLink&utm_medium=affiliate&utm_source=commission_junction&utm_campaign=3_nsn6445_deeplink&utm_content=deeplink)

Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on October 20, 2016, 05:19:55 PM
The linked reference takes a large-scale "interplanetary" viewpoint on understanding the technosphere as an emergent new Earth system:

Bronislaw Szerszynski (October 19, 2016), "Viewing the technosphere in an interplanetary light", The Anthropocene Review 2053019616670676,  doi:10.1177/2053019616670676

http://anr.sagepub.com/content/early/2016/10/18/2053019616670676.abstract (http://anr.sagepub.com/content/early/2016/10/18/2053019616670676.abstract)

Abstract: "I argue that discussion about the ‘technosphere’ as an emergent new Earth system needs to be situated within wider reflection about how technospheres might arise on other worlds. Engaging with astrobiological speculation about ‘exo-technospheres’ can help us to understand whether technospheres are likely, what their preconditions might be, and whether they endure. Engaging with science fiction can help us to avoid observer biases that encourage linear assumptions about the preconditions and emergence of technospheres. Exploring earlier major transitions in Earth’s evolution can shed light on the shifting distribution of metabolic and reproductive powers between the human and technological parts of the contemporary technosphere. The long-term evolution of technical objects also suggests that they have shown a tendency to pass through their own major transitions in their relation to animality. Such reflection can shed new light on the nature and likely future development of the Earth’s technosphere."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on December 14, 2016, 12:37:57 AM
The linked reference discusses how the Pacific Northwest National Laboratory has an improved statistical representation of clouds in a climate model.

Mikhail Ovchinnikov et al. Vertical overlap of probability density functions of cloud and precipitation hydrometeors, Journal of Geophysical Research: Atmospheres (2016). DOI: 10.1002/2016JD025158

http://onlinelibrary.wiley.com/doi/10.1002/2016JD025158/abstract;jsessionid=E9709CEDF25DA1CFC3CDE8C5A584C95A.f04t02?systemMessage=Wiley+Online+Library+will+be+unavailable+on+Saturday+17th+December+2016+at+09%3A00+GMT%2F+04%3A00+EST%2F+17%3A00+SGT+for+4hrs+due+to+essential+maintenance.Apologies+for+the+inconvenience (http://onlinelibrary.wiley.com/doi/10.1002/2016JD025158/abstract;jsessionid=E9709CEDF25DA1CFC3CDE8C5A584C95A.f04t02?systemMessage=Wiley+Online+Library+will+be+unavailable+on+Saturday+17th+December+2016+at+09%3A00+GMT%2F+04%3A00+EST%2F+17%3A00+SGT+for+4hrs+due+to+essential+maintenance.Apologies+for+the+inconvenience)

Abstract: "Coarse-resolution climate models increasingly rely on probability density functions (PDFs) to represent subgrid-scale variability of prognostic variables. While PDFs characterize the horizontal variability, a separate treatment is needed to account for the vertical structure of clouds and precipitation. When subcolumns are drawn from these PDFs for microphysics or radiation parameterizations, appropriate vertical correlations must be enforced via PDF overlap specifications. This study evaluates the representation of PDF overlap in the Subgrid Importance Latin Hypercube Sampler (SILHS) employed in the assumed PDF turbulence and cloud scheme called the Cloud Layers Unified by Binormals (CLUBB). PDF overlap in CLUBB-SILHS simulations of continental and tropical oceanic deep convection is compared with overlap of PDF of various microphysics variables in cloud-resolving model (CRM) simulations of the same cases that explicitly predict the 3-D structure of cloud and precipitation fields. CRM results show that PDF overlap varies significantly between different hydrometeor types, as well as between PDFs of mass and number mixing ratios for each species—a distinction that the current SILHS implementation does not make. In CRM simulations that explicitly resolve cloud and precipitation structures, faster falling species, such as rain and graupel, exhibit significantly higher coherence in their vertical distributions than slow falling cloud liquid and ice. These results suggest that to improve the overlap treatment in the subcolumn generator, the PDF correlations need to depend on hydrometeor properties, such as fall speeds, in addition to the currently implemented dependency on the turbulent convective length scale."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on January 07, 2017, 01:15:49 AM
Currently consensus climate change model projections do not clearly identify the risk of meaningful abrupt climate change this century.  The linked reference discusses efforts to make progress to more clearly identify such potential risks:

Sebastian Bathiany, Henk Dijkstra, Michel Crucifix, Vasilis Dakos, Victor Brovkin, Mark S. Williamson, Timothy M. Lenton & Marten Scheffer (2016), "Beyond bifurcation – using complex models to understand and predict abrupt climate change", Dynamics and Statistics of the Climate System, DOI: https://doi.org/10.1093/climsys/dzw004 (https://doi.org/10.1093/climsys/dzw004)

https://academic.oup.com/climatesystem/article/doi/10.1093/climsys/dzw004/2562885/Beyond-bifurcation-using-complex-models-to (https://academic.oup.com/climatesystem/article/doi/10.1093/climsys/dzw004/2562885/Beyond-bifurcation-using-complex-models-to)

or

http://oup.silverchair-cdn.com/oup/backfile/Content_public/Journal/climatesystem/PAP/10.1093_climsys_dzw004/2/dzw004.pdf?Expires=1484090692&Signature=OU5CJq40-BAF7TUuvDW7b~ze0Y3umsbKCcFMppiFuYltT1Sda8-W5CRFwC~DbJRM-PYs51uI2lS4kBO-AP0FsnvCS98OlekOoJrKQZftL1dwlFFCnqaNvTdCAqJDpkQX99YtDLm4FvNfCPn21SH2OdW0AneZAMCJLru-U3~D7IdFbJZr6rDrjkE5lB9HWkhGvCaecDmFGfklhzyDsH3MFvCcRgtqvQlNfwJL8HebsouM1A4eIszFr6Q4ZKDL9QzByPHhwRjOV7qt~Nn53lUiiEdunY8rXJdLXs78s09CBBJ2h3NT-E0QJY~jTRdBs4ogkFmXJqzpPoCIG6YbErjoWw__&Key-Pair-Id=APKAIUCZBIA4LVPAVW3Q (http://oup.silverchair-cdn.com/oup/backfile/Content_public/Journal/climatesystem/PAP/10.1093_climsys_dzw004/2/dzw004.pdf?Expires=1484090692&Signature=OU5CJq40-BAF7TUuvDW7b~ze0Y3umsbKCcFMppiFuYltT1Sda8-W5CRFwC~DbJRM-PYs51uI2lS4kBO-AP0FsnvCS98OlekOoJrKQZftL1dwlFFCnqaNvTdCAqJDpkQX99YtDLm4FvNfCPn21SH2OdW0AneZAMCJLru-U3~D7IdFbJZr6rDrjkE5lB9HWkhGvCaecDmFGfklhzyDsH3MFvCcRgtqvQlNfwJL8HebsouM1A4eIszFr6Q4ZKDL9QzByPHhwRjOV7qt~Nn53lUiiEdunY8rXJdLXs78s09CBBJ2h3NT-E0QJY~jTRdBs4ogkFmXJqzpPoCIG6YbErjoWw__&Key-Pair-Id=APKAIUCZBIA4LVPAVW3Q)

Abstract: "Research on the possibility of future abrupt climate change has been popularised under the term “tipping points”, and has often been motivated by using simple, low-dimensional, concepts. These include the iconic fold bifurcation, where abrupt change occurs when a stable equilibrium is lost, and early warning signals of such a destabilisation that can be derived based on a simple stochastic model approach. In this paper we review the challenges and limitations that are associated with this view, and we discuss promising research paths to explore the causes and the likelihood of abrupt changes in future climate.

We focus on several climate system components and ecosystems that have been proposed as candidates of tipping points, with an emphasis on ice sheets, the Atlantic Ocean circulation, vegetation in North Africa, and Arctic sea ice. In most example cases, multiple equilibria found in simple models do not appear in complex models or become more difficult to find, while the potential for abrupt change still remains. We also discuss how the low-dimensional logic of current methods to detect and interpret the existence of multiple equilibria can fail in complex models. Moreover, we highlight promising methods to detect abrupt shifts, and to obtain information about the mechanisms behind them. These methods include linear approaches such as statistical stability indicators and radiative feedback analysis, as well as non-linear approaches to detect dynamical transitions and infer the causality behind events.

Given the huge complexity of comprehensive process-based climate models and the non-linearity and regional peculiarities of the processes involved, the uncertainties associated with the possible future occurrence of abrupt shifts are large and not well quantified. We highlight the potential of data mining approaches to tackle this problem, and finally discuss how the scientific community can collaborate to make efficient progress in understanding abrupt climate shifts."
Title: Re: Modelling the Anthropocene
Post by: DrTskoul on January 07, 2017, 01:37:27 AM
Interesting paper.  I have only dealt with fluid dynamic instabilities in simple systems close to equilibrium , I wonder how large departures from equilibrium ( due to our ever increasing radiative forcing )  and the properties of non equilibrium thermodynamics can affect our ability to study abrupt changes in the earth system. 
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on January 07, 2017, 03:20:04 AM
Interesting paper.  I have only dealt with fluid dynamic instabilities in simple systems close to equilibrium , I wonder how large departures from equilibrium ( due to our ever increasing radiative forcing )  and the properties of non equilibrium thermodynamics can affect our ability to study abrupt changes in the earth system.

Climate change is wicked problem, and depending on the complexity (or wickedness) of such problems, solutions to such problems may be uncalculatable in reasonable timespan and thus require alternate approximate approaches/strategies such as those discussed in the following Wikipedia article focused on social policy planning:

https://en.wikipedia.org/wiki/Wicked_problem (https://en.wikipedia.org/wiki/Wicked_problem)

However, science has advanced sense C. West Churchman introduced the term "wick problem", and this post focuses on how chaos theory, strange attractors, information networks and energy landscapes can be used to create and calibrate alternate models for wick problems (including better understanding how systemic isolation leads to a lack of human willpower to effective tackle climate change)

The first linked article is entitled: "A mathematical view on personality"; and it introduces the concept of how attractors can be used to model the human psyche within a network (including the use of energy landscape concepts).

http://blogs.plos.org/neuro/2016/03/21/a-mathematical-view-on-personality-by-solve-saebo/ (http://blogs.plos.org/neuro/2016/03/21/a-mathematical-view-on-personality-by-solve-saebo/)


Extract: "Interestingly, more diffuse properties of the human psyche, like personality (Van Eenwyk, 1997) and consciousness (Tononi, 2004) may, in fact, be connected to mathematical properties of networks, and in this post I will focus on what mathematics can teach us about these matters.

In mathematics there are complex models for information transfer across networks called attractor networks, and the neural network of our brain appears to be well approximated by these models

Attractor networks are built from nodes (for example neurons) which typically are recurrently linked (loops) with edges (like synaptic connections), and the dynamics of the network tend to stabilize at least locally to certain patterns. These stable patterns are the attractors. For example, a memory stored in long time memory may be considered as a so-called point attractor, a subnetwork of strongly connected neurons.

The point attractors are low-energy states in an energy landscape with surrounding basins of attraction, much like hillsides surrounding the bottom of a valley, as shown in the figure below. {see the first attached image}

Also other types of mathematical attractors exist, like line-, plane- and cyclic attractors, and these have been used to explain neural responses like eye-vision control and cyclic motor control, like walking and chewing (Eliasmith, 2005).
Common to these attractors are their stability and predictability, and this is good with regard to having stable memory and stable bodily control, but what about personality? Is personality also an attractor? Do we all have our basins of attraction, which pulls our personality towards stable behavior?

Probably yes, but if you think about it, personality is a more unpredictable property than memory and body control. We think we know someone, and the suddenly they behave in an unexpected manner. Still, the overall personality seems to be more or less stable. How can something be both stable and unpredictable at the same time?

Well there is another class of attractors that may occur in attractor networks. These are the strange (or chaotic) attractors, and they are exactly that, partly stable and partly unpredictable. We say they are bounded, but non-repeating.

A famous example is the Lorenz attractor discovered by Edward Lorenz while he was programming his “weather machine” where typical weather patterns appeared, but never repeated themselves. In the figure below {see the second attached image} the blue curve is pulled towards the red strange attractor state, and once it enters the attractor, it is bound to follow a certain pattern, though it never repeats itself.

The discovery of strange attractors led to the development of chaos theory and fractal geometry in mathematics. Many phenomena around us may develop smoothly in linear predictable fashions until a certain border is reached, at which point a chaotic state appears before a new order may be settled."


The second linked reference cites the development of a dissipative strange attractor that coexists with an invariant conservative torus that can be used to better model brain dynamics.

Artuor Tozzi and James F. Peters (2016), "TOWARDS EQUATIONS FOR BRAIN DYNAMICS AND THE CONCEPT OF EXTENDED CONNECTOME"

http://rxiv.org/pdf/1609.0045v1.pdf (http://rxiv.org/pdf/1609.0045v1.pdf)

Abstract: "The brain is a system at the edge of chaos equipped with nonlinear dynamics and functional energetic landscapes.  However, still doubts exist concerning the type of attractors or the trajectories followed by particles in the nervous phase space. Starting from an unusual system governed by differential equations in which a dissipative strange attractor coexists with an invariant conservative torus, we developed a 3D model of brain phase space which has the potential to be operationalized and assessed empirically. We achieved a system displaying both a torus and a strange attractor, depending just on the initial conditions. Further, the system generates a funnel-like attractor equipped with a fractal structure. Changes in three easily detectable brain phase parameters (log frequency, excitatory/inhibitory ratio and fractal slope) lead to modifications in funnel’s breadth or in torus/attractor superimposition: it explains a large repertoire of brain functions and activities, such as sensations/perceptions, memory and self-generated thoughts."

Extract: "Starting from the unusual Sprott’s system of ODEs, we built a system equipped with both a conservative torus and a dissipative strange attractor. When a moving particle starts its trajectory from a given position x,y,z in the 3D nervous phase space, we may predict whether it will fall in the torus or into the strange attractor. The funnel shape is fractal, and not just a simple fixed-point attractor. A narrower funnel means that the trajectory is constrained towards a small zone of the phase space. When the two structures are closely superimposed, we might hypothesize a state of phase transition at the edge of the chaos, equipped with high symmetry, in which it is difficult to evaluate every single initial position: a slightly change in the starting point could indeed lead to completely different outcomes. When the torus and the strange attractor are clearly splitted, a single starting point gives rise to a sharp outcome. It means that in the latter case, the two conformations are neatly separated, as if the system went out of phase transition and a symmetry breaking occurred."

The third linked reference develops the concept of an attractor network to better understand how to calibrate nonlinear dynamical networks.
Wang et al (2016), "A geometrical approach to control and controllability of nonlinear dynamical networks", Nature communications 7, Article No. 11323, doi: 10.1038/ncomms11323.


http://www.nature.com/articles/ncomms11323 (http://www.nature.com/articles/ncomms11323)


The fourth linked reference and the associated fifth linked article, discuss a new efficient Monte Carlo method that can be used to more efficiently find solutions to models of wick problems:

Stefano Martiniani et al. Structural analysis of high-dimensional basins of attraction, Physical Review E (2016). DOI: 10.1103/PhysRevE.94.031301


http://journals.aps.org/pre/abstract/10.1103/PhysRevE.94.031301 (http://journals.aps.org/pre/abstract/10.1103/PhysRevE.94.031301)

Abstract: "We propose an efficient Monte Carlo method for the computation of the volumes of high-dimensional bodies with arbitrary shape. We start with a region of known volume within the interior of the manifold and then use the multistate Bennett acceptance-ratio method to compute the dimensionless free-energy difference between a series of equilibrium simulations performed within this object. The method produces results that are in excellent agreement with thermodynamic integration, as well as a direct estimate of the associated statistical uncertainties. The histogram method also allows us to directly obtain an estimate of the interior radial probability density profile, thus yielding useful insight into the structural properties of such a high-dimensional body. We illustrate the method by analyzing the effect of structural disorder on the basins of attraction of mechanically stable packings of soft repulsive spheres."


The linked article is entitled: "New method for making effective calculations in 'high-dimensional space'".

http://phys.org/news/2016-10-method-effective-high-dimensional-space.html (http://phys.org/news/2016-10-method-effective-high-dimensional-space.html)


Extract: " Researchers have developed a new method for making effective calculations in "high-dimensional space" – and proved its worth by using it to solve a 93-dimensional problem.


Those include, for example, trying to model the likely shape and impact of a decaying ecosystem, such as a developing area of deforestation, or the potential effect of different levels of demand on a power grid.


"There is a very large class of problems that can be solved through the sort of approach that we have devised," Martiniani said. "It opens up a whole world of possibilities in the study of things like dynamical systems, chemical structure prediction, or artificial neural networks."


The set of initial conditions leading to this stable state is called a "basin of attraction". The fundamental theory is that, if the volume of each basin of attraction can be calculated, then this begins to provide some sort of indication of the probability of a given state's occurrence."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on February 01, 2017, 04:02:31 AM
The linked reference discusses the importance of correctly modeling vegetation processes in ESM w.r.t. Fast precipitation response to carbon dioxide forcing:

DeAngelis AM, Qu X & Hall A  (2016), "Importance of Vegetation Processes for Model Spread in the Fast Precipitation Response to CO2 Forcing." Geophysical Research Letters.;43:12550-12559, DOI: 10.1002/2016GL071392

http://onlinelibrary.wiley.com/doi/10.1002/2016GL071392/full (http://onlinelibrary.wiley.com/doi/10.1002/2016GL071392/full)

Abstract: “In the current generation of climate models, the projected increase in global precipitation over the 21st century ranges from 2% to 10% under a high-emission scenario. Some of this uncertainty can be traced to the rapid response to carbon dioxide (CO2) forcing. We analyze an ensemble of simulations to better understand model spread in this rapid response. A substantial amount is linked to how the land surface partitions a change in latent versus sensible heat flux in response to the CO2-induced radiative perturbation; a larger increase in sensible heat results in a larger decrease in global precipitation. Model differences in the land surface response appear to be strongly related to the vegetation response to increased CO2, specifically, the closure of leaf stomata. Future research should thus focus on evaluation of the vegetation physiological response, including stomatal conductance parameterizations, for the purpose of constraining the fast response of Earth’s hydrologic cycle to CO2 forcing.”
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on February 09, 2017, 07:36:25 PM
The linked reference cites progress being made in the application of modeling Lorenz atmospheric attractors (chaos theory) focused on the North Atlantic.  Such research may someday help to better define climate sensitivity.

Davide Faranda, Gabriele Messori & Pascal Yiou (2017), "Dynamical proxies of North Atlantic predictability and extremes", Nature, Scientific Reports 7, Article number: 41278, doi:10.1038/srep41278

https://hal.archives-ouvertes.fr/hal-01340301/document

Abstract: "Atmospheric flows are characterized by chaotic dynamics and recurring large-scale patterns. These two characteristics point to the existence of an atmospheric attractor defined by Lorenz as: “the collection of all states that the system can assume or approach again and again, as opposed to those that it will ultimately avoid”. The average dimension D of the attractor corresponds to the number of degrees of freedom sufficient to describe the atmospheric circulation. However, obtaining reliable estimates of D has proved challenging . Moreover, D does not provide information on transient atmospheric motions, which lead to weather extremes . Using recent developments in dynamical systems theory, we show that such motions can be classified through instantaneous rather than average properties of the attractor. The instantaneous properties are uniquely determined by instantaneous dimension and stability. Their extreme values correspond to specific atmospheric patterns, and match extreme weather occurrences. We further show the existence of a significant correlation between the time series of instantaneous stability and dimension and the mean spread of sea-level pressure fields in an operational ensemble weather forecast at steps of over two weeks. We believe this method provides an efficient and practical way of evaluating and informing operational weather forecasts."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on February 10, 2017, 07:53:08 PM
The linked reference is entitled: "The Anthropocene equation".  The associated image implies that climate sensitivity in the Anthropocene will likely be higher than in the paleorecord due the action of climate attractors.

http://journals.sagepub.com/doi/full/10.1177/2053019616688022 (http://journals.sagepub.com/doi/full/10.1177/2053019616688022)

Extract: "The dominant external forces influencing the rate of change of the Earth System have been astronomical and geophysical during the planet’s 4.5-billion-year existence. In the last six decades, anthropogenic forcings have driven exceptionally rapid rates of change in the Earth System. This new regime can be represented by an ‘Anthropocene equation’, where other forcings tend to zero, and the rate of change under human influence can be estimated. Reducing the risk of leaving the glacial–interglacial limit cycle of the late Quaternary for an uncertain future will require, in the first instance, the rate of change of the Earth System to become approximately zero."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on February 12, 2017, 06:07:27 PM
The linked article entitled: "Humans causing climate to change 170 times faster than natural forces", provides back-up discussion to my Reply #97:

https://www.skepticalscience.com/2017-SkS-Weekly-Digest_06.html (https://www.skepticalscience.com/2017-SkS-Weekly-Digest_06.html)
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on February 14, 2017, 08:15:56 PM
The linked reference discusses efforts to make model calibration more transparent.

Schmidt, G. A., Bader, D., Donner, L. J., Elsaesser, G. S., Golaz, J.-C., Hannay, C., Molod, A., Neale, R., and Saha, S.: Practice and philosophy of climate model tuning across six U.S. modeling centers, Geosci. Model Dev. Discuss., doi:10.5194/gmd-2017-30, in review, 2017.

http://www.geosci-model-dev-discuss.net/gmd-2017-30/ (http://www.geosci-model-dev-discuss.net/gmd-2017-30/)

Abstract. Model calibration (or "tuning") is a necessary part of developing and testing coupled ocean-atmosphere climate models regardless of their main scientific purpose. There is an increasing recognition that this process needs to become more transparent for both users of climate model output and other developers. Knowing how and why climate models are tuned and which targets are used is essential to avoiding possible misattributions of skillful predictions to data accommodation and vice versa. This paper describes the approach and practice of model tuning for the six major U.S. climate modeling centers. While details differ among groups in terms of scientific missions, tuning targets and tunable parameters, there is a core commonality of approaches. However, practices differ significantly on some key aspects, in particular, in the use of initialized forecast analyses as a tool, the explicit use of the historical transient record, and the use of the present day radiative imbalance vs. the implied balance in the pre-industrial as a target.
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on February 18, 2017, 04:10:21 PM
The linked (open access) reference indicates that the current IPCC assessment models miss critical dynamic human-earth systems feedback mechanisms that means that our current assessments significantly underestimate coming impacts (see image of different types of possible collapses under our influence).

Safa Motesharrei et al, Modeling Sustainability: Population, Inequality, Consumption, and Bidirectional Coupling of the Earth and Human Systems, National Science Review (2016). DOI: 10.1093/nsr/nww081 

https://academic.oup.com/nsr/article-lookup/doi/10.1093/nsr/nww081

Abstract: “Over the last two centuries, the impact of the Human System has grown dramatically, becoming strongly dominant within the Earth System in many different ways. Consumption, inequality, and population have increased extremely fast, especially since about 1950, threatening to overwhelm the many critical functions and ecosystems of the Earth System. Changes in the Earth System, in turn, have important feedback effects on the Human System, with costly and potentially serious consequences. However, current models do not incorporate these critical feedbacks. We argue that in order to understand the dynamics of either system, Earth System Models must be coupled with Human System Models through bidirectional couplings representing the positive, negative, and delayed feedbacks that exist in the real systems. In particular, key Human System variables, such as demographics, inequality, economic growth, and migration, are not coupled with the Earth System but are instead driven by exogenous estimates, such as United Nations population projections. This makes current models likely to miss important feedbacks in the real Earth–Human system, especially those that may result in unexpected or counterintuitive outcomes, and thus requiring different policy interventions from current models. The importance and imminence of sustainability challenges, the dominant role of the Human System in the Earth System, and the essential roles the Earth System plays for the Human System, all call for collaboration of natural scientists, social scientists, and engineers in multidisciplinary research and modeling to develop coupled Earth–Human system models for devising effective science-based policies and measures to benefit current and future generations.”

Significance Statement: “The Human System has become strongly dominant within the Earth System in many different ways. However, in current models that explore the future of humanity and environment, and guide policy, key Human System variables, such as demographics, inequality, economic growth, and migration, are not coupled with the Earth System but are instead driven by exogenous estimates such as United Nations (UN) population projections. This makes the models likely to miss important feedbacks in the real Earth–Human system that may result in unexpected outcomes requiring very different policy interventions. The importance of humanity's sustainability challenges calls for collaboration of natural and social scientists to develop coupled Earth–Human system models for devising effective science-based policies and measures.”

See also the associated linked article entitled: “It's more than just climate change”.

https://phys.org/news/2017-02-climate_1.html


Extract: “Co-author Matthias Ruth, Director and Professor at the School of Public Policy and Urban Affairs, Northeastern University, said: "The result of not dynamically modeling these critical Human-Earth System feedbacks would be that the environmental challenges humanity faces may be significantly underestimated. Moreover, there's no explicit role given to policies and investments to actively shape the course in which the dynamics unfold. Rather, as the models are designed now, any intervention—almost by definition—comes from the outside and is perceived as a cost. Such modeling, and the mindset that goes with it, leaves no room for creativity in solving some of the most pressing challenges."

"The paper correctly highlights that other human stressors, not only the climate ones, are very important for long-term sustainability, including the need to reduce inequality'', said Carlos Nobre (not a co-author), one of the world's leading Earth System scientists, who recently won the prestigious Volvo Environment Prize in Sustainability for his role in understanding and protecting the Amazon. "Social and economic equality empowers societies to engage in sustainable pathways, which includes, by the way, not only the sustainable use of natural resources but also slowing down population growth, to actively diminish the human footprint on the environment."

Michael Mann, Distinguished Professor and Director of the Earth System Science Center at Penn State University, who was not a co-author of the paper, commented: "We cannot separate the issues of population growth, resource consumption, the burning of fossil fuels, and climate risk. They are part of a coupled dynamical system, and, as the authors show, this has dire potential consequences for societal collapse. The implications couldn't be more profound."”
Title: Re: Modelling the Anthropocene
Post by: sidd on February 18, 2017, 06:57:20 PM
Thanks for the Motasharrei et. al link to human influenced models. I reviewed his 2014 publication (ref 134 in this one, http://www.sciencedirect.com/science/article/pii/S0921800914000615 (http://www.sciencedirect.com/science/article/pii/S0921800914000615) which oddly enuf has no doi) while reading this one, especially the graphs (including Fig 5 in the present review which you attached.)

In some of the 2014 results we see oscillations, and in others we do not. In the old days we used to call these underdamped and overdamped cases. It might be interesting to apply the methods of Sugihara(2012, doi:10.1126/science.1227079 ) and Ye(2015, http://www.pnas.org/cgi/doi/10.1073/pnas.1417063112 (http://www.pnas.org/cgi/doi/10.1073/pnas.1417063112) ) directly to the underdamped cases, while the overdamped ones might require rotation to imaginary time and back after the calculation.

I think i have some of the code written ... I may have to take a look

sidd
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on February 18, 2017, 09:00:29 PM
I think i have some of the code written ... I may have to take a look

sidd,

If you get your model calibrated, see if you can include the impacts of a human-climate interaction mechanism coded as a strange attractor feeding into a meltdown of the entire financial system (maybe you can numerically show the elite that they suffer more losses than their collective guts are telling them):

See the linked article entitled: "Climate change could threaten entire financial system, APRA warns"

http://www.abc.net.au/news/2017-02-17/climate-change-could-threaten-entire-financial-system-apra/8281436 (http://www.abc.net.au/news/2017-02-17/climate-change-could-threaten-entire-financial-system-apra/8281436)

Extract: "Climate change could threaten the stability of the entire financial system, the prudential regulator has warned, as it prepares to apply climate change "stress tests" to the nation's financial institutions.

In its first major speech on climate change, the Australian Prudential Regulation Authority chastised companies for a lack of action on the risks it poses."

Best regards,
ASLR
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on February 18, 2017, 09:47:57 PM
The linked reference examines the sensitivity of Shared Socioeconomic Pathways to changes in key parameters & finds that energy intensity and economic growth are the two most important determinants of future GHG emissions.  Now all we have to do is to convince people (including elites) to use less energy (of all types) and to accept less economic growth.

G. Marangoni, et. al. (2017), "Sensitivity of projected long-term CO2 emissions across the Shared Socioeconomic Pathways", Nature Climate Change, Volume: 7, Pages: 113–117, doi:10.1038/nclimate3199

http://www.nature.com/nclimate/journal/v7/n2/full/nclimate3199.html (http://www.nature.com/nclimate/journal/v7/n2/full/nclimate3199.html)

Abstract: "Scenarios showing future greenhouse gas emissions are needed to estimate climate impacts and the mitigation efforts required for climate stabilization. Recently, the Shared Socioeconomic Pathways (SSPs) have been introduced to describe alternative social, economic and technical narratives, spanning a wide range of plausible futures in terms of challenges to mitigation and adaptation. Thus far the key drivers of the uncertainty in emissions projections have not been robustly disentangled. Here we assess the sensitivities of future CO2 emissions to key drivers characterizing the SSPs. We use six state-of-the-art integrated assessment models with different structural characteristics, and study the impact of five families of parameters, related to population, income, energy efficiency, fossil fuel availability, and low-carbon energy technology development. A recently developed sensitivity analysis algorithm allows us to parsimoniously compute both the direct and interaction effects of each of these drivers on cumulative emissions. The study reveals that the SSP assumptions about energy intensity and economic growth are the most important determinants of future CO2 emissions from energy combustion, both with and without a climate policy. Interaction terms between parameters are shown to be important determinants of the total sensitivities."
Title: Re: Modelling the Anthropocene
Post by: sidd on February 18, 2017, 10:14:58 PM
My ideas at the moment  to take the model output (HANDY) in Motasharrei(2014), then real world data and

1)  use the empirical dynamic method in Ye(2015) to see if in fact there is at all evidence for the efficacy of the Sugihara(2012) method     
`
2) if there is, use cross convergence as in Sugihara(2012) to attemp to untangle causality between various outcomes

3) Either 1) or 2) could be used for prediction

4) Coupling financial systems into HANDY is not something i would untertake lightly. I have a more general idea in mind toward those ends, which would take me to far afield to explain fully at the moment. But briefly, the idea is to investigate the stability of the dynamical orbits describing the system (stability of projections into lower dimensional spaces from the full manifold, if you like). Once that is done i think coupling to other dynamical systems such as financial/economic/... ones would be much easier, since one could establish at a glance (well, a few glances and based on the independent behaviour of each system you were trying to couple) what the effect of the coupling on each would be.

5) Another powerful idea is from the notion of transfer entropy as in Liang(2015, doi:10.1103/PhysRevE.90.052150 ) to detect causality _and_ stabilization between time series. I have already coded to combine transfer entropy with cross convergence and empirical dynamical methods. The strength of this combination is that it winnows the relevant subspaces down to those which capture the essentials of the dynamics. Thus we only have to look at a few possible combinations for the relevant subspaces, neatly evading combinatorial explosion (i hope)

6) I can do all this from realworld time series (as I have already done in some ecological systems) or from the HANDY output. My instinct is to jump right into real data, but i need to get some familiarity with these methods on simple (ha!) models before diving into the cold and deep pools of reality

The program outlined above is very easy to conceive, on a sunny afternoon in Philly, sitting on a deck outside, drinking hi test microbrew, and cheeping back at the birds and miaowing at itinerant cats. How much of it i actually get done I cannot say.

sidd
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on February 18, 2017, 10:41:25 PM
The program outlined above is very easy to conceive, on a sunny afternoon in Philly, sitting on a deck outside, drinking hi test microbrew, and cheeping back at the birds and miaowing at itinerant cats. How much of it i actually get done I cannot say.

Godspeed, John Glenn.
Title: Re: Modelling the Anthropocene
Post by: sidd on February 19, 2017, 05:32:46 AM
"Godspeed, John Glenn."

Heehee. I didn't think I was quite so obviously dead yet. 

His funeral was on a bitingly cold day in Columbus, OH. They had an imressive turnout for the weather, but then ohioans, even the soft ones in columbus, are quite stoic. I was in columbus then, but did not attend.

There are little towns in ohio like Cambridge and New Concord where he grew up, and I have been thru many times. They have seen hard times.

sidd
Title: Re: Modelling the Anthropocene
Post by: bligh8 on February 21, 2017, 08:24:15 AM
Hey…..wow, such musings on a Saturday afternoon in April, a breath of fresh air indeed.

Fair Winds
bligh
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on March 06, 2017, 07:52:22 PM
The linked open access reference discusses various techniques to expand current ESMs to better human behavior:

Finn Müller-Hansen, Maja Schlüter, Michael Mäs, Rainer Hegselmann, Jonathan F. Donges, Jakob J. Kolb, Kirsten Thonicke, and Jobst Heitzig (2017), "How to represent human behavior and decision making in Earth system models? A guide to techniques and approaches", Earth Syst. Dynam. Discuss., doi:10.5194/esd-2017-18

http://www.earth-syst-dynam-discuss.net/esd-2017-18/esd-2017-18.pdf (http://www.earth-syst-dynam-discuss.net/esd-2017-18/esd-2017-18.pdf)

Abstract: "In the Anthropocene, humans have a critical impact on the Earth system and vice versa, which can generate complex feedback processes between social and ecological dynamics. Integrating human behavior into formal Earth System Models (ESMs), however, requires crucial modeling assumptions about actors and their goals, behavioral options and decision rules, as well as modeling decisions regarding human social interactions and the aggregation of individuals' behavior. In this tutorial review, we compare existing modeling approaches and techniques from different disciplines and schools of thought dealing with human behavior at various levels of decision making. Providing an overview over social-scientific modeling approaches, we demonstrate modelers' often vast degrees of freedom but also seek to make modelers aware of the often crucial consequences of seemingly innocent modeling assumptions.

After discussing which socio-economic units are potentially important for ESMs, we review models of individual decision making that correspond to alternative behavioral theories and that make diverse modeling assumptions about individuals' preferences, beliefs, decision rules, and foresight. We discuss approaches to model social interaction, covering game theoretic frameworks, models of social influence and network models. Finally, we elaborate approaches to study how the behavior of individuals, groups and organizations can aggregate to complex collective phenomena, discussing agent-based, statistical and representative-agent modeling and economic macro-dynamics. We illustrate the main ingredients of modeling techniques with examples from land-use dynamics as one of the main drivers of environmental change bridging local to global scales."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on March 15, 2017, 10:26:03 PM
The linked reference uses Amazonian deep convective clouds as an example of the valued of using the Gamma phase space for modeling clouds:

Cecchini, M. A., Machado, L. A. T., Wendisch, M., Costa, A., Krämer, M., Andreae, M. O., Afchine, A., Albrecht, R. I., Artaxo, P., Borrmann, S., Fütterer, D., Klimach, T., Mahnke, C., Martin, S. T., Minikin, A., Molleker, S., Pardo, L. H., Pöhlker, C., Pöhlker, M. L., Pöschl, U., Rosenfeld, D., and Weinzierl, B.: Illustration of microphysical processes in Amazonian deep convective clouds in the Gamma phase space: Introduction and potential applications, Atmos. Chem. Phys. Discuss., doi:10.5194/acp-2017-185, in review, 2017.

http://www.atmos-chem-phys-discuss.net/acp-2017-185/ (http://www.atmos-chem-phys-discuss.net/acp-2017-185/)

Abstract. The behavior of tropical clouds remains a major open scientific question, given that the associated phys-ics is not well represented by models. One challenge is to realistically reproduce cloud droplet size dis-tributions (DSD) and their evolution over time and space. Many applications, not limited to models, use the Gamma function to represent DSDs. However, there is almost no study dedicated to understanding the phase space of this function, which is given by the three parameters that define the DSD intercept, shape, and curvature. Gamma phase space may provide a common framework for parameterizations and inter-comparisons. Here, we introduce the phase-space approach and its characteristics, focusing on warm-phase microphysical cloud properties and the transition to the mixed-phase layer. We show that trajectories in this phase space can represent DSD evolution and can be related to growth processes. Condensational and collisional growth may be interpreted as pseudo-forces that induce displacements in opposite directions within the phase space. The actually observed movements in the phase space are a result of the combination of such pseudo-forces. Additionally, aerosol effects can be evaluated given their significant impact on DSDs. The DSDs associated with liquid droplets that favor cloud glaciation can be delimited in the phase space, which can help models to adequately predict the transition to the mixed phase. We also consider possible ways to constrain the DSD in two-moment bulk microphysics schemes, where the relative dispersion parameter of the DSD can play a significant role. Overall, the Gamma phase-space approach can be an invaluable tool for studying cloud microphysical evolution and can be readily applied in many scenarios that rely on Gamma DSDs.
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on March 16, 2017, 03:34:21 AM
The linked reference discusses the use of Wasserstein distance can be used to better understand climate attractors.

Robin, Y., Yiou, P., and Naveau, P.: Detecting Changes in Forced Climate Attractors with Wasserstein Distance, Nonlin. Processes Geophys. Discuss., doi:10.5194/npg-2017-5, in review, 2017.

http://www.nonlin-processes-geophys-discuss.net/npg-2017-5/ (http://www.nonlin-processes-geophys-discuss.net/npg-2017-5/)

Abstract. The climate system can been described by a dynamical system and its associated attractor. The dynamics of this attractor depends on the external forcings that influence the climate. Such forcings can affect the mean values or variances, but regions of the attractor that are seldom visited can also be affected. It is an important challenge to measure how the climate attractor responds to different forcings. Currently, the Euclidean distance or similar measures like the Mahalanobis distance have been favoured to measure discrepancies between two climatic situations. Those distances do not have a natural building mechanism to take into account the attractor dynamics. In this paper, we argue that a Wasserstein distance, stemming from optimal transport theory, offers an efficient and practical way to discriminate between dynamical systems. After treating a toy example, we explore how the Wasserstein distance can be applied and interpreted to detect non-autonomous dynamics from a Lorenz system driven by seasonal cycles and a warming trend.

For the open access pdf see:

http://www.nonlin-processes-geophys-discuss.net/npg-2017-5/npg-2017-5.pdf (http://www.nonlin-processes-geophys-discuss.net/npg-2017-5/npg-2017-5.pdf)

Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on March 22, 2017, 06:23:30 PM
The linked reference discusses model projected changes in extreme precipitation with global warming; and indicates that rainfall will likely increase through 2100; which to my mind will (among other things) accelerate degradation of permafrost.

Guiling Wang, Dagang Wang, Kevin E. Trenberth, Amir Erfanian, Miao Yu, Michael G. Bosilovich, & Dana T. Parr (2017), "The peak structure and future changes of the relationships between extreme precipitation and temperature", Nature Climate Change, doi:10.1038/nclimate3239

http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate3239.html (http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate3239.html)

Abstract: "Theoretical models predict that, in the absence of moisture limitation, extreme precipitation intensity could exponentially increase with temperatures at a rate determined by the Clausius–Clapeyron (C–C) relationship.  Climate models project a continuous increase of precipitation extremes for the twenty-first century over most of the globe. However, some station observations suggest a negative scaling of extreme precipitation with very high temperatures, raising doubts about future increase of precipitation extremes. Here we show for the present-day climate over most of the globe, the curve relating daily precipitation extremes with local temperatures has a peak structure, increasing as expected at the low–medium range of temperature variations but decreasing at high temperatures. However, this peak-shaped relationship does not imply a potential upper limit for future precipitation extremes. Climate models project both the peak of extreme precipitation and the temperature at which it peaks (Tpeak) will increase with warming; the two increases generally conform to the C–C scaling rate in mid- and high-latitudes, and to a super C–C scaling in most of the tropics. Because projected increases of local mean temperature (Tmean) far exceed projected increases of Tpeak over land, the conventional approach of relating extreme precipitation to Tmean produces a misleading sub-C–C scaling rate."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on May 04, 2017, 01:05:02 AM
The linked reference & associated article indicate that CMIP5 climate models can be corrected to accurately hind-caste the faux hiatus:

Iselin Medhaug, Martin B. Stolpe, Erich M. Fischer& Reto Knutti (2017), "Reconciling controversies about the ‘global warming hiatus’", Nature, doi:10.1038/nature22315

http://www.nature.com/nature/journal/v545/n7652/full/nature22315.html (http://www.nature.com/nature/journal/v545/n7652/full/nature22315.html)

http://www.nature.com/articles/nature22315.epdf?referrer_access_token=JLkSn0TiKxcgOZC96Yyo1tRgN0jAjWel9jnR3ZoTv0NuFtYPLl1PUnqxUYbpB1uVru_rIjRyseUxK8YNRXQS41-Xf6ZZogTkPn3KRcKavtILhD4coONJlcGDCKvzDODIkuk843_-Ed8uysUYSjoO1mnSC9MKgJe-AEdiQrYEil_J7dXfrqXcEk3aUKEwwbhH12BmIcywDhqQFLGneIRyuBCPPM_uThqWtrjDhaarzoM2Q58JLurh9B00TC_dOiOwjlp9Kpu1_r9BOi4c5Nq5AA%3D%3D&tracking_referrer=www.latimes.com (http://www.nature.com/articles/nature22315.epdf?referrer_access_token=JLkSn0TiKxcgOZC96Yyo1tRgN0jAjWel9jnR3ZoTv0NuFtYPLl1PUnqxUYbpB1uVru_rIjRyseUxK8YNRXQS41-Xf6ZZogTkPn3KRcKavtILhD4coONJlcGDCKvzDODIkuk843_-Ed8uysUYSjoO1mnSC9MKgJe-AEdiQrYEil_J7dXfrqXcEk3aUKEwwbhH12BmIcywDhqQFLGneIRyuBCPPM_uThqWtrjDhaarzoM2Q58JLurh9B00TC_dOiOwjlp9Kpu1_r9BOi4c5Nq5AA%3D%3D&tracking_referrer=www.latimes.com)

Abstract: "Between about 1998 and 2012, a time that coincided with political negotiations for preventing climate change, the surface of Earth seemed hardly to warm. This phenomenon, often termed the ‘global warming hiatus’, caused doubt in the public mind about how well anthropogenic climate change and natural variability are understood. Here we show that apparently contradictory conclusions stem from different definitions of ‘hiatus’ and from different datasets. A combination of changes in forcing, uptake of heat by the oceans, natural variability and incomplete observational coverage reconciles models and data. Combined with stronger recent warming trends in newer datasets, we are now more confident than ever that human influence is dominant in long-term warming."


See also the linked article entitled: "Detailed look at the global warming ‘hiatus’ again confirms that humans are changing the climate"

http://www.latimes.com/science/sciencenow/la-sci-sn-global-warming-hiatus-20170503-htmlstory.html (http://www.latimes.com/science/sciencenow/la-sci-sn-global-warming-hiatus-20170503-htmlstory.html)

Extract: "For years, the global warming ‘hiatus’ from 1998 to 2012 puzzled scientists and fueled skeptics looking to cast doubt on the very idea that Earth’s temperature has been on the rise, largely because of human-produced greenhouse gas emissions such as carbon dioxide — and that significant policy changes would need to be made to keep that rise in check.
Recent papers have begun to chip away at the idea of the slowdown. Now, a new analysis in the journal Nature brings together many of those arguments to show that the hiatus may not have been quite what it seemed."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on May 17, 2017, 10:11:10 PM
The linked reference indicates that we need to pay more attention to changes to extreme precipitation patterns with continued global warming:

Geert Lenderink & Hayley J. Fowler (2017), "Hydroclimate: Understanding rainfall extremes", Nature Climate Change, doi:10.1038/nclimate3305

https://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate3305.html (https://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate3305.html)

Extract: "Warming induced by greenhouse gases will increase the amount of moisture in the atmosphere, causing heavier rainfall events. Changing atmospheric circulation dynamics are now shown to either amplify or weaken regional increases, contributing to uncertainty in future precipitation extremes."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on May 19, 2017, 05:22:23 PM
The linked reference finds that: "The model predicts that land surfaces have a 50% greater climate sensitivity than ocean surfaces, and that the nighttime temperatures on land increase about twice as much as daytime temperatures because of the absence of turbulent fluxes at night."

Kleidon, A. and Renner, M.: An explanation for the different climate sensitivities of land and ocean surfaces based on the diurnal cycle, Earth Syst. Dynam. Discuss., doi:10.5194/esd-2017-44, in review, 2017

http://www.earth-syst-dynam-discuss.net/esd-2017-44/ (http://www.earth-syst-dynam-discuss.net/esd-2017-44/)

Abstract. Observations and climate model simulations consistently show a higher climate sensitivity of land surfaces compared to ocean surfaces, with the cause for this difference being still unclear. Here we show that this difference in temperature sensitivity can be explained by the different means by which the diurnal variation in solar radiation is buffered. While ocean surfaces buffer the diurnal variations by heat storage changes below the surface, land surfaces buffer it mostly by heat storage changes above the surface in the lower atmosphere that are reflected in the diurnal growth of a convective boundary layer. Storage changes below the surface allow the ocean surface-atmosphere system to maintain turbulent fluxes over day and night, while the land surface-atmosphere system maintains turbulent fluxes only during the daytime hours when the surface is heated by absorption of solar radiation. This shorter duration of turbulent fluxes on land then results in a greater sensitivity of the land surface-atmosphere system to changes in the greenhouse forcing because nighttime temperatures are then shaped by radiative exchange only, which are more sensitive to changes in greenhouse forcing. We use a simple, analytic energy balance model of the surface-atmosphere system in which turbulent fluxes are constrained by the maximum power limit to estimate the effects of these different means to buffer the diurnal cycle on the resulting temperature sensitivities. The model predicts that land surfaces have a 50% greater climate sensitivity than ocean surfaces, and that the nighttime temperatures on land increase about twice as much as daytime temperatures because of the absence of turbulent fluxes at night. Both predictions compare very well with observations and CMIP 5 climate model simulations. Hence, the greater climate sensitivity of land surfaces can be explained by its buffering of diurnal variations of solar radiation in the lower atmosphere.
Title: Re: Modelling the Anthropocene
Post by: gerontocrat on May 27, 2017, 03:25:29 PM
I am looking for a model that predicts the probability for and date of a post-Anthropocene world, i.e. when humans have damaged the world and themselves as a species so badly that humans' further influence on the planet is minimal. (Feeling pessimistic today)
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on May 28, 2017, 01:44:29 AM
gerontocrat,

If you accept the logic that our modern global socio-economic system will collapse (including into: warfare, famine, drought, disease & financial ruin) when the West Antarctic Ice Sheet collapses (together with meaningful ice mass loss from Greenland) due both the abrupt sea level rise (ASLR) and Hansen's ice-climate feedback, then the attached image may answer your question. The image shows my proposed PDFs and CDFs associated with RSLR for California for the years 2070 and 2100; assuming that we follow RCP 8.5 through at least 2035.

While all of my posts assume this probability distribution, the following two threads are useful to understand the logic behind these curves.

Thread: "Potential Collapse Scenario for the WAIS"
http://forum.arctic-sea-ice.net/index.php/topic,31.0.html (http://forum.arctic-sea-ice.net/index.php/topic,31.0.html)

&
Thread: "Hansen et al paper: 3+ meters SLR by 2100"
http://forum.arctic-sea-ice.net/index.php/topic,1327.0.html (http://forum.arctic-sea-ice.net/index.php/topic,1327.0.html)

Best ASLR
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on June 06, 2017, 04:02:18 PM
Accurately projecting the sensitivity of the hydraulic cycle is critical to estimating climate change impact:

James J. Benedict, Brian Medeiros, Amy C. Clement & Angeline G. Pendergrass (1 June 2017), "Sensitivities of the hydrologic cycle to model physics, grid resolution, and ocean type in the aquaplanet Community Atmosphere Model", JAMES, DOI: 10.1002/2016MS000891

http://onlinelibrary.wiley.com/doi/10.1002/2016MS000891/full (http://onlinelibrary.wiley.com/doi/10.1002/2016MS000891/full)

Abstract: "Precipitation distributions and extremes play a fundamental role in shaping Earth's climate and yet are poorly represented in many global climate models. Here, a suite of idealized Community Atmosphere Model (CAM) aquaplanet simulations is examined to assess the aquaplanet's ability to reproduce hydroclimate statistics of real-Earth configurations and to investigate sensitivities of precipitation distributions and extremes to model physics, horizontal grid resolution, and ocean type. Little difference in precipitation statistics is found between aquaplanets using time-constant sea-surface temperatures and those implementing a slab ocean model with a 50 m mixed-layer depth. In contrast, CAM version 5.3 (CAM5.3) produces more time mean, zonally averaged precipitation than CAM version 4 (CAM4), while CAM4 generates significantly larger precipitation variance and frequencies of extremely intense precipitation events. The largest model configuration-based precipitation sensitivities relate to choice of horizontal grid resolution in the selected range 1–2°. Refining grid resolution has significant physics-dependent effects on tropical precipitation: for CAM4, time mean zonal mean precipitation increases along the Equator and the intertropical convergence zone (ITCZ) narrows, while for CAM5.3 precipitation decreases along the Equator and the twin branches of the ITCZ shift poleward. Increased grid resolution also reduces light precipitation frequencies and enhances extreme precipitation for both CAM4 and CAM5.3 resulting in better alignment with observational estimates. A discussion of the potential implications these hydrologic cycle sensitivities have on the interpretation of precipitation statistics in future climate projections is also presented."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on June 10, 2017, 04:20:05 AM
The linked opinion article recommends the use of climate model pluralism in order to better represent complex Earth Systems:

FULVIO MAZZOCCHI, ANTONELLO PASINI(May 31 2017), "Climate model pluralism beyond dynamical ensembles", WIRES Climate Change, DOI: 10.1002/wcc.477

http://wires.wiley.com/WileyCDA/WiresArticle/wisId-WCC477.html (http://wires.wiley.com/WileyCDA/WiresArticle/wisId-WCC477.html)


Abstract: "Using pluralist research strategies can be a profitable way to study complex systems. This contribution focuses on the approaches for studying the climate that make use of multiple different models, aiming to increase the reliability (in terms of robustness) of attribution results. This Opinion article argues that the traditional approach, which is based on ensemble runs of global climate models, only partially allows the application of a robustness scheme, owing to the difficulty to match or evaluate the conditions required for robustness (i.e., independence or heterogeneity among models). An alternative ‘multi‐approach’ strategy is advanced, beyond dynamical modeling but still preserving the idea of model pluralism. Such a strategy, which uses a set of ensembles of different model types by combining dynamical modeling with data‐driven methodological approaches (i.e., neural networks and Granger causality), seems to better match the condition of independence. In addition, neural networks and Granger causality lead to achievements in attribution studies that can complement those obtained by dynamical modeling."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on June 13, 2017, 02:57:13 PM
Projecting extreme hydroclimatic events is important but challenging, & the linked reference uses Bayesian multi-model projections to make progress on this issue:

Qiao-Hong Sun, et. al. (2017), "Bayesian multi-model projections of extreme hydroclimatic events under RCPs scenarios", Advances in Climate Change Research, https://doi.org/10.1016/j.accre.2017.06.001 (https://doi.org/10.1016/j.accre.2017.06.001)

http://www.sciencedirect.com/science/article/pii/S1674927816300934 (http://www.sciencedirect.com/science/article/pii/S1674927816300934)

Abstract: "A Bayesian multi-model inference framework was used to assess the changes in the occurrence of extreme hydroclimatic events in four major river basins in China (i.e., Liaohe River Basin, Yellow River Basin, Yangtze River Basin, and Pearl River Basin) under RCP2.6, RCP4.5, and RCP8.5 scenarios using multiple global climate model projections from the IPCC Fifth Assessment Report. The results projected more summer days and fewer frost days in 2006‒2099. The ensemble prediction shows the Pearl River Basin is projected to experience more summer days than other basins with the increasing trend of 16.3, 38.0, and 73.0 d per 100 years for RCP 2.6, RCP 4.5 and RCP 8.5, respectively. Liaohe River Basin and Yellow River Basin are forecasted to become wetter and warmer with the co-occurrence of increases in summer days and wet days. Very heavy precipitation days (R20, daily precipitation ≥20 mm) are projected to increase in all basins. The R20 in the Yangtze River Basin are projected to have the highest change rate in 2006‒2099 of 1.8, 2.5, and 3.8 d per 100 years for RCP 2.6, RCP 4.5 and RCP 8.5, respectively."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on June 17, 2017, 07:03:28 PM
The two linked references indicate that CMIP5 projections lack sufficient dynamical behavior to model decadal variations in the rate of global warming:

Shuai-Lei Yao et al, Distinct global warming rates tied to multiple ocean surface temperature changes, Nature Climate Change (2017). DOI: 10.1038/nclimate3304

https://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate3304.html (https://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate3304.html)

Abstract: "The globally averaged surface temperature has shown distinct multi-decadal fluctuations since 1900, characterized by two weak slowdowns in the mid-twentieth century and early twenty-first century and two strong accelerations in the early and late twentieth century. While the recent global warming (GW) hiatus has been particularly ascribed to the eastern Pacific cooling, causes of the cooling in the mid-twentieth century and distinct intensity differences between the slowdowns and accelerations remain unclear. Here, our model experiments with multiple ocean sea surface temperature (SST) forcing reveal that, although the Pacific SSTs play essential roles in the GW rates, SST changes in other basins also exert vital influences. The mid-twentieth-century cooling results from the SST cooling in the tropical Pacific and Atlantic, which is partly offset by the Southern Ocean warming. During the recent hiatus, the tropical Pacific-induced strong cooling is largely compensated by warming effects of other oceans. In contrast, during the acceleration periods, ubiquitous SST warming across all the oceans acts jointly to exaggerate the GW. Multi-model simulations with separated radiative forcing suggest diverse causes of the SST changes in multiple oceans during the GW acceleration and slowdown periods. Our results highlight the importance of multiple oceans on the multi-decadal GW rates."

&

Power et. al. (2017), "Apparent limitations in the ability of CMIP5 climate models to simulate recent multi-decadal change in surface temperature: implications for global temperature projections", Clim Dyn (2017) 49: 53. doi:10.1007/s00382-016-3326-x

https://link.springer.com/article/10.1007%2Fs00382-016-3326-x?utm_content=buffer44ff8&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer (https://link.springer.com/article/10.1007%2Fs00382-016-3326-x?utm_content=buffer44ff8&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer)

Abstract: "Observed surface temperature trends over the period 1998–2012/2014 have attracted a great deal of interest because of an apparent slowdown in the rate of global warming, and contrasts between climate model simulations and observations of such trends. Many studies have addressed the statistical significance of these relatively short-trends, whether they indicate a possible bias in the model values and the implications for global warming generally. Here we re-examine these issues, but as they relate to changes over much longer-term changes. We find that on multi-decadal time scales there is little evidence for any change in the observed global warming rate, but some evidence for a recent temporary slowdown in the warming rate in the Pacific. This multi-decadal slowdown can be partly explained by a cool phase of the Interdecadal Pacific Oscillation and a short-term excess of La Niña events. We also analyse historical and projected changes in 38 CMIP climate models. All of the model simulations examined simulate multi-decadal warming in the Pacific over the past half-century that exceeds observed values. This difference cannot be fully explained by observed internal multi-decadal climate variability, even if allowance is made for an apparent tendency for models to underestimate internal multi-decadal variability in the Pacific. Models which simulate the greatest global warming over the past half-century also project warming that is among the highest of all models by the end of the twenty-first century, under both low and high greenhouse gas emission scenarios. Given that the same models are poorest in representing observed multi-decadal temperature change, confidence in the highest projections is reduced."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on June 18, 2017, 06:12:23 PM
The linked reference discusses incremental progress in modeling temporal fluctuations (such as the faux hiatus) in GMSTA:

Hege-Beate Fredriksen and Martin Rypdal (2017), "Long-range persistence in global surface temperatures explained by linear multi-box energy balance models", Journal of Climate, https://doi.org/10.1175/JCLI-D-16-0877.1 (https://doi.org/10.1175/JCLI-D-16-0877.1)

http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-16-0877.1?utm_content=buffer22000&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer (http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-16-0877.1?utm_content=buffer22000&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer)

Abstract: "The temporal fluctuations in global mean surface temperature is an example of a geophysical quantity which can be described using the notions of long-range persistence and scale invariance/scaling, but this description has suffered from lack of a generally accepted physical explanation. Processes with these statistical signatures can arise from non-linear effects, for instance through cascade-like energy transfer in turbulent fluids, but they can also be produced by linear models with scale-invariant impulse-response functions. This paper demonstrates that on time scales from months to centuries, the scale-invariant impulse-response function of global surface temperature can be explained from simple linear multi-box energy balance models. This explanation describes both the scale invariance of the internal variability and the lack of a characteristic time scale of the response to external forcings. With parameters estimated from observational data, the climate response is approximately scaling in these models, even if the response function is not chosen to be scaling a priori. It is also demonstrated that the differences in scaling exponents for temperatures over land and for sea-surface temperatures can be reproduced by a version of the multi-box energy balance model with two distinct surface boxes."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on July 03, 2017, 03:57:39 PM
The linked reference uses a CMIP type of climate model to examine the strengths of different carbon cycles during glacial and interglacial periods.  They find that overall climate sensitivity is stronger during interglacial periods such as we live in now.  However, I note that if their model errs on the side of least drama then so do their findings:


Adloff, M., Reick, C. H., and Claussen, M.: Earth system model simulations show different carbon cycle feedback strengths under glacial and interglacial conditions, Earth Syst. Dynam. Discuss., https://doi.org/10.5194/esd-2017-67, (https://doi.org/10.5194/esd-2017-67,) in review, 2017.

http://www.earth-syst-dynam-discuss.net/esd-2017-67/ (http://www.earth-syst-dynam-discuss.net/esd-2017-67/)

Abstract. In Earth system model simulations we find different carbon cycle sensitivities for recent and glacial climate. This result is obtained by comparing the transient response of the terrestrial carbon cycle to a fast and strong atmospheric CO2 concentration increase (roughly 1000ppm) in C4MIP type simulations starting from climate conditions of the Last Glacial Maximum (LGM) and from Pre-Industrial times (PI). The sensitivity β to CO2 fertilization is larger in the LGM experiment during most of the simulation time: The fertilization effect leads to a terrestrial carbon gain in the LGM experiment almost twice as large as in the PI experiment. The larger fertilization effect in the LGM experiment is caused by the stronger initial CO2 limitation of photosynthesis, implying a stronger potential for its release upon CO2 concentration increase. In contrast, the sensitivity γ to climate change induced by the radiation effect of rising CO2 is larger in the PI experiment for most of the simulation time. Yet, climate change is less pronounced in the PI experiment, resulting in only slightly higher terrestrial carbon losses than in the LGM experiment. The stronger climate sensitivity in the PI experiment results from the vastly more extratropical soil carbon under those interglacial conditions whose respiration is enhanced under climate change. Comparing the radiation and fertilization effect in a factor analysis, we find that they are almost additive, i.e. their synergy is small in the global sum of carbon changes. From this additivity, we find that the carbon cycle feedback strength is more negative in the LGM than in the PI simulations.
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on July 05, 2017, 07:37:55 PM
The linked article provides an overview of the CMIP project including CMIP6:

Title: "Highlight article: WCRP’s Coupled Model Intercomparison Project: a remarkable contribution to climate science".

http://www.egu.eu/news/highlight-articles/586/wcrps-coupled-model-intercomparison-project-a-remarkable-contribution-to-climate-science/ (http://www.egu.eu/news/highlight-articles/586/wcrps-coupled-model-intercomparison-project-a-remarkable-contribution-to-climate-science/)

Extract: "CMIP6 confronts a number of new challenges. More centers will run more versions of more models of increasing complexity. An ongoing demand to resolve more processes requires increasingly higher model resolutions. Archiving, documenting, subsetting, supporting, distributing, and analyzing the petabytes of CMIP6 model outputs will challenge the capacity and creativity of the largest data centres and fastest data networks. Fundamentally, CMIP6 will allow continuous and flexible model innovation schedules while remaining mindful of the IPCC process, will ensure that CMIP products address priorities identified by the climate research community, and will foster open and inclusive participation. Prof Veronika Eyring, researcher at the German Aerospace Center (DLR) and Chair of the CMIP Panel, outlines that “with CMIP6 we aim to achieve a balance between fundamental improvements of our modeling skills and rapid progress on urgent science questions – not an easy task for the modeling centres and researchers who analyze the data.”

The growing dependency on CMIP products by a broad research community and by national and international climate assessments means that basic CMIP activities, such as the creation of forcing datasets, the provision and archiving of CMIP products, and model development, require substantial efforts. CMIP continues to rely heavily on volunteer efforts by enthusiastic climate researchers. It represents one of society’s most robust and reliable sources for climate information – a source that deserves international acclaim and substantial ongoing support."
Title: Re: Modelling the Anthropocene
Post by: Andre on July 06, 2017, 01:34:02 AM
Crossposted from Consequences thread, as I believe it fits here too.

It is starting to look more and more like we arent so lucky and climate sensitivity might be much higher than anticipated so far:

https://www.theguardian.com/environment/2017/jul/05/hopes-of-mild-climate-change-dashed-by-new-research?CMP=Share_iOSApp_Other (https://www.theguardian.com/environment/2017/jul/05/hopes-of-mild-climate-change-dashed-by-new-research?CMP=Share_iOSApp_Other)

Hopes of mild climate change dashed by new research

"Hopes that the world’s huge carbon emissions might not drive temperatures up to dangerous levels have been dashed by new research.

The work shows that temperature rises measured over recent decades do not fully reflect the global warming already in the pipeline and that the ultimate heating of the planet could be even worse than feared.

How much global temperatures rise for a certain level of carbon emissions is called climate sensitivity and is seen as the single most important measure of climate change. Computer models have long indicated a high level of sensitivity, up to 4.5C for a doubling of CO2 in the atmosphere.

However in recent years estimates of climate sensitivity based on historical temperature records from the past century or so have suggested the response might be no more than 3C. This would mean the planet could be kept safe with lower cuts in emissions, which are easier to achieve.

But the new work, using both models and paleoclimate data from warming periods in the Earth’s past, shows that the historical temperature measurements do not reveal the slow heating of the planet’s oceans that takes place for decades or centuries after CO2 has been added to the atmosphere.

“The hope was that climate sensitivity was lower and the Earth is not going to warm as much,” said Cristian Proistosescu, at Harvard University in the US, who led the new research. “There was this wave of optimism.”

The new research, published in the journal Science Advances, has ended that. “The worrisome part is that all the models show there is an amplification of the amount of warming in the future,” he said. The situation might be even worse, as Proistosescu’s work shows climate sensitivity could be as high as 6C."


The Guardian article is based on this paper:

http://advances.sciencemag.org/content/3/7/e1602821 (http://advances.sciencemag.org/content/3/7/e1602821)
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on July 13, 2017, 06:20:23 PM
Per the linked reference, climate models need to do a better job of accounting for the feedback between human and natural processes in the land Earth Systems:

Robinson, D. T., Di Vittorio, A., Alexander, P., Arneth, A., Barton, C. M., Brown, D. G., Kettner, A., Lemmen, C., O'Neill, B. C., Janssen, M., Pugh, T. A. M., Rabin, S. S., Rounsevell, M., Syvitski, J. P., Ullah, I., and Verburg, P. H.: Modelling feedbacks between human and natural processes in the land system, Earth Syst. Dynam. Discuss., https://doi.org/10.5194/esd-2017-68, (https://doi.org/10.5194/esd-2017-68,) in review, 2017.

http://www.earth-syst-dynam-discuss.net/esd-2017-68/ (http://www.earth-syst-dynam-discuss.net/esd-2017-68/)

Abstract. The unprecedented use of Earth's resources by humans, in combination with the increasing natural variability in natural processes over the past century, is affecting evolution of the Earth system. To better understand natural processes and their potential future trajectories requires improved integration with and quantification of human processes. Similarly, to mitigate risk and facilitate socio-economic development requires a better understanding of how the natural system (e.g., climate variability and change, extreme weather events, and processes affecting soil fertility) affects human processes. To capture and formalize our understanding of the interactions and feedback between human and natural systems a variety of modelling approaches are used. While integrated assessment models are widely recognized as supporting this goal and integrating representations of the human and natural system for global applications, an increasing diversity of models and corresponding research have focused on coupling models specializing in specific human (e.g., decision-making) or natural (e.g., erosion) processes at multiple scales. Domain experts develop these specialized models with a greater degree of detail, accuracy, and transparency, with many adopting open-science norms that use new technology for model sharing, coupling, and high performance computing. We highlight examples of four different approaches used to couple representations of the human and natural system, which vary in the processes represented and in the scale of their application. The examples illustrate how groups of researchers have attempted to overcome the lack of suitable frameworks for coupling human and natural systems to answer questions specific to feedbacks between human and natural systems. We draw from these examples broader lessons about system and model coupling and discuss the challenges associated with maintaining consistency across models and representing feedback between human and natural systems in coupled models.
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on July 13, 2017, 08:01:50 PM
Most IAM projections are so poor that researchers don't even bother to do hind-caste evaluations to help calibrate their future modeling development.  The linked reference provides recommendations on how to begin to address this short-coming in the IAM field:

Snyder, A. C., Link, R. P., and Calvin, K. V.: Evaluation of Integrated Assessment Model hindcast experiments: A case study of the GCAM 3.0 land use module, Geosci. Model Dev. Discuss., https://doi.org/10.5194/gmd-2017-97, (https://doi.org/10.5194/gmd-2017-97,) in review, 2017.

http://www.geosci-model-dev-discuss.net/gmd-2017-97/ (http://www.geosci-model-dev-discuss.net/gmd-2017-97/)

Abstract. Hindcasting experiments (conducting a model forecast for a time period in which observational data is available) are rarely undertaken in the Integrated Assessment Model (IAM) community. When they are undertaken, the results are often evaluated using global aggregates or otherwise highly aggregated skill scores that mask deficiencies. We select a set of deviation based measures that can be applied at different spatial scales (regional versus global) to make evaluating the large number of variable-region combinations in IAMs more tractable. We also identify performance benchmarks for these measures, based on the statistics of the observational dataset, that allow a model to be evaluated in absolute terms rather than relative to the performance of other models at similar tasks. This is key in the integrated assessment community, where there often are not multiple models conducting hindcast experiments to allow for model intercomparison. The performance benchmarks serve a second purpose, providing information about the reasons a model may perform poorly on a given measure and therefore identifying opportunities for improvement. As a case study, the measures are applied to the results of a past hindcast experiment focusing on land allocation in the Global Change Assessment Model (GCAM) version 3.0. We find quantitative evidence that global aggregates alone are not sufficient for evaluating IAMs, such as GCAM, that require global supply to equal global demand at each time period. Additionally, the deviation measures examined in this work successfully identity parametric and structural changes that may improve land allocation decisions in GCAM. Future work will involve implementing the suggested improvements to the GCAM land allocation system identified by the measures in this work, using the measures to quantify performance improvement due to these changes, and, ideally, applying these measures to other sectors of GCAM and other land allocation models.
Title: Re: Modelling the Anthropocene
Post by: rboyd on July 13, 2017, 09:11:53 PM
In the financial world this is called "backtesting the models", a very good idea indeed. The problem is when the past does not represent the future correctly, as seen when all the models failed in 2008. Their biggest problem was the assumption of liquidity (the availability of willing buyers) and a normal distribution of outcomes (as against skew and "fat tails"). This latter problem lead to "stress testing".

It looks like the IAM modellers have not learnt much from the failure of the financial modellers. The IAM version of liquidity is the assumption that food exports will be available during a food shortage - already shown to be completely unrealistic. Another is that the financial system will continue to function perfectly as the climate goes to hell ("Ceterus Paribus" is a wonderful economics assumptions - "all other things remain the same").

Yep, the IAMs are pretty much useless.
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on July 16, 2017, 06:31:05 PM
Correctly projecting changes in the ENSO cycle, with continued global warming, is important w.r.t. correctly estimating ECS this century:

Bayr, T., Latif, M., Dommenget, D. et al. (2017), "Mean-state dependence of ENSO atmospheric feedbacks in climate models", Clim Dyn, doi:10.1007/s00382-017-3799-2

https://link.springer.com/article/10.1007%2Fs00382-017-3799-2?utm_content=buffer87cf6&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer

Extract: "We investigate the dependence of ENSO atmospheric feedbacks on the mean-state in a perturbed atmospheric physics ensemble with the Kiel Climate Model (KCM) and in CMIP5 models. Additionally, uncoupled simulations are conducted with the atmospheric component of the KCM to obtain further insight into the mean-state dependence. It is found that the positive zonal wind feedback and the negative heat flux feedback, with the short-wave flux as dominant component, are strongly linearly related through sea surface temperature (SST) and differences in model physics are less important. In observations, strong zonal wind and heat flux feedbacks are caused by a convective response in the western central equatorial Pacific (Niño4 region), resulting from an eastward (westward) shift of the rising branch of the Walker Circulation (WC) during El Niño (La Niña). Many state-of-the-art climate models exhibit an equatorial cold SST bias in the Niño4 region, i.e. are in a La Niña-like mean-state. Therefore they simulate a too westward located rising branch of the WC (by up to 30°) and only a weak convective response. Thus, the position of the WC determines the strength of both the amplifying wind and usually damping heat flux feedback, which also explains why biases in these two feedbacks partly compensate in many climate models. Furthermore, too weak atmospheric feedbacks can cause quite different ENSO dynamics than observed, while enhanced atmospheric feedbacks lead to a substantial improvement of important ENSO properties such as seasonal ENSO phase locking and asymmetry between El Niño and La Niña. Differences in the mean-state SST are suggested to be a major source of ENSO diversity in current climate models."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on July 17, 2017, 03:50:25 AM
The linked reference discusses cloud feedback mechanisms & how they are modeled, including the possibility that the net cloud feedback might be significantly positive and may have a significant dynamical impact of both climate and weather:

Paulo Ceppi, Florent Brient, Mark D. Zelinka & Dennis L. Hartmann (2017), “Cloud feedback mechanisms and their representation in global climate models”, WIREs Clim Change, 8:e465. doi: 10.1002/wcc.465

http://onlinelibrary.wiley.com/doi/10.1002/wcc.465/abstract (http://onlinelibrary.wiley.com/doi/10.1002/wcc.465/abstract)

http://www.atmos.washington.edu/~dennis/cloud_fdbk_review_revised.pdf (http://www.atmos.washington.edu/~dennis/cloud_fdbk_review_revised.pdf)

Abstract: “Cloud feedback—the change in top-of-atmosphere radiative flux resulting from the cloud response to warming—constitutes by far the largest source of uncertainty in the climate response to CO2forcing simulated by global climate models (GCMs). We review the main mechanisms for cloud feedbacks, and discuss their representation in climate models and the sources of intermodel spread. Global-mean cloud feedback in GCMs results from three main effects: (1) rising free-tropospheric clouds (a positive longwave effect); (2) decreasing tropical low cloud amount (a positive shortwave [SW] effect); (3) increasing high-latitude low cloud optical depth (a negative SW effect). These cloud responses simulated by GCMs are qualitatively supported by theory, high-resolution modeling, and observations. Rising high clouds are consistent with the fixed anvil temperature (FAT) hypothesis, whereby enhanced upper-tropospheric radiative cooling causes anvil cloud tops to remain at a nearly fixed temperature as the atmosphere warms. Tropical low cloud amount decreases are driven by a delicate balance between the effects of vertical turbulent fluxes, radiative cooling, large-scale subsidence, and lower-tropospheric stability on the boundary-layer moisture budget. High-latitude low cloud optical depth increases are dominated by phase changes in mixed-phase clouds. The causes of intermodel spread in cloud feedback are discussed, focusing particularly on the role of unresolved parameterized processes such as cloud microphysics, turbulence, and convection.”
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on July 17, 2017, 05:07:18 AM
I think that we will all be unpleasantly surprised by how rapidly methane emissions from thermokarst lakes will increase in the coming decades:

Alex Matveev, Isabelle Laurion, Bethany N. Deshpande, Najat Bhiry & Warwick F. Vincent (2017), “High methane emissions from thermokarst lakes in subarctic peatlands”, Limnology and Oceanography, DOI: 10.1002/lno.10311

http://onlinelibrary.wiley.com/doi/10.1002/lno.10311/abstract (http://onlinelibrary.wiley.com/doi/10.1002/lno.10311/abstract)

Abstract: “The thawing and subsidence of frozen peat mounds (palsas) in permafrost landscapes results in the formation of organic-rich thermokarst lakes. We examined the effects of palsa degradation on CH4 and CO2 emissions by comparing thermokarst lakes at two peatland locations in subarctic Québec, Canada: in the northern discontinuous permafrost region, and in southern sporadic permafrost where palsas are more rapidly degrading. The lakes were shallow (< 3 m) but stratified at both sites, and most had anoxic bottom waters. The surface waters at both sites were supersaturated in CH4 and CO2, and to a greater extent in the southern lakes, where the surface CH4 concentrations were up to 3 orders of magnitude above air equilibrium. Concentrations of CH4 and CO2 increased by orders of magnitude with depth in the southern lakes, however these gradients were less marked or absent in the North. Strong CH4 and CO2 emissions were associated with gas ebullition, but these were greatly exceeded by diffusive fluxes, in contrast to thermokarst lakes studied elsewhere. Also unusual relative to other studies to date, the surface concentrations of both gases increased as a linear function of water column depth, with highest values over the central, deepest portion of the lakes. Radiocarbon dating of ebullition gas samples showed that the CH4 had 14C-ages from 760 yr to 2005 yr before present, while the CO2 was consistently younger.  Peatland thermokarst lakes may be an increasingly important source of greenhouse gases as the southern permafrost limit continues to shift northwards.”
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on July 17, 2017, 11:39:28 PM
The linked reference highlights the importance of using multiple oceans when using climate models to project multi-decadal rates of global warming:

Shuai-Lei Yao, Jing-Jia Luo, Gang Huang & Pengfei Wang (2017), "Distinct global warming rates tied to multiple ocean surface temperature changes", Nature Climate Change,  7,  486–491, doi:10.1038/nclimate3304

http://www.nature.com/nclimate/journal/v7/n7/full/nclimate3304.html (http://www.nature.com/nclimate/journal/v7/n7/full/nclimate3304.html)

Abstract: "The globally averaged surface temperature has shown distinct multi-decadal fluctuations since 1900, characterized by two weak slowdowns in the mid-twentieth century and early twenty-first century and two strong accelerations in the early and late twentieth century. While the recent global warming (GW) hiatus has been particularly ascribed to the eastern Pacific cooling, causes of the cooling in the mid-twentieth century and distinct intensity differences between the slowdowns and accelerations remain unclear. Here, our model experiments with multiple ocean sea surface temperature (SST) forcing reveal that, although the Pacific SSTs play essential roles in the GW rates, SST changes in other basins also exert vital influences. The mid-twentieth-century cooling results from the SST cooling in the tropical Pacific and Atlantic, which is partly offset by the Southern Ocean warming. During the recent hiatus, the tropical Pacific-induced strong cooling is largely compensated by warming effects of other oceans. In contrast, during the acceleration periods, ubiquitous SST warming across all the oceans acts jointly to exaggerate the GW. Multi-model simulations with separated radiative forcing suggest diverse causes of the SST changes in multiple oceans during the GW acceleration and slowdown periods. Our results highlight the importance of multiple oceans on the multi-decadal GW rates."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on July 17, 2017, 11:48:18 PM
The linked reference discusses improved modeling of biospheric feedback effects in a synchronously coupled model of human and Earth systems:

Peter E. Thornton, et. al. (2017), "Biospheric feedback effects in a synchronously coupled model of human and Earth systems", Nature Climate Change, 7,  496–500, doi:10.1038/nclimate3310

http://www.nature.com/nclimate/journal/v7/n7/full/nclimate3310.html (http://www.nature.com/nclimate/journal/v7/n7/full/nclimate3310.html)

Abstract: "Fossil fuel combustion and land-use change are the two largest contributors to industrial-era increases in atmospheric CO 2 concentration. Projections of these are thus fundamental inputs for coupled Earth system models (ESMs) used to estimate the physical and biological consequences of future climate system forcing. While historical data sets are available to inform past and current climate analyses, assessments of future climate change have relied on projections of energy and land use from energy–economic models, constrained by assumptions about future policy, land-use patterns and socio-economic development trajectories. Here we show that the climatic impacts on land ecosystems drive significant feedbacks in energy, agriculture, land use and carbon cycle projections for the twenty-first century. We find that exposure of human-appropriated land ecosystem productivity to biospheric change results in reductions of land area used for crops; increases in managed forest area and carbon stocks; decreases in global crop prices; and reduction in fossil fuel emissions for a low–mid-range forcing scenario. The feedbacks between climate-induced biospheric change and human system forcings to the climate system—demonstrated here—are handled inconsistently, or excluded altogether, in the one-way asynchronous coupling of energy–economic models to ESMs used to date."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on July 21, 2017, 05:11:26 PM
In the way of color commentary, it seems to me that the linked reference (and associated article) about biospheric feedback effect in a synchronously coupled model of human and Earth system is a play to try to document the potential validity of negative emissions technology like BECCS using ACME (Phase 1).  While ACME tries to account for the impact of phosphorous on the biosphere, I am concerned that much of their focus on BECCS is just happy talk, which will not prevent a socio-economic collapse in the 2050 to 2060 timeframe.  Nevertheless, it appears that these BECCS assumptions & associated projections will be rolled into both CMIP6 and AR6 to further the illusion that the situation is in capable hands (i.e. the DOE [which runs ACME] controlled by Rick Perry).

Peter E. Thornton et al, Biospheric feedback effects in a synchronously coupled model of human and Earth systems, Nature Climate Change (2017). DOI: 10.1038/nclimate3310

http://www.nature.com/nclimate/journal/v7/n7/full/nclimate3310.html?foxtrotcallback=true (http://www.nature.com/nclimate/journal/v7/n7/full/nclimate3310.html?foxtrotcallback=true)

Abstract: "Fossil fuel combustion and land-use change are the two largest contributors to industrial-era increases in atmospheric CO 2 concentration. Projections of these are thus fundamental inputs for coupled Earth system models (ESMs) used to estimate the physical and biological consequences of future climate system forcing. While historical data sets are available to inform past and current climate analyses, assessments of future climate change have relied on projections of energy and land use from energy–economic models, constrained by assumptions about future policy, land-use patterns and socio-economic development trajectories. Here we show that the climatic impacts on land ecosystems drive significant feedbacks in energy, agriculture, land use and carbon cycle projections for the twenty-first century. We find that exposure of human-appropriated land ecosystem productivity to biospheric change results in reductions of land area used for crops; increases in managed forest area and carbon stocks; decreases in global crop prices; and reduction in fossil fuel emissions for a low–mid-range forcing scenario. The feedbacks between climate-induced biospheric change and human system forcings to the climate system—demonstrated here—are handled inconsistently, or excluded altogether, in the one-way asynchronous coupling of energy–economic models to ESMs used to date."

See also the associated linked article entitled:  Titan simulations show importance of close two-way coupling between human and Earth systems"

https://phys.org/news/2017-07-titan-simulations-importance-two-way-coupling.html (https://phys.org/news/2017-07-titan-simulations-importance-two-way-coupling.html)

Extract: "Through the Advanced Scientific Computing Research Leadership Computing Challenge program, Thornton's team was awarded 85 million compute hours to improve the Accelerated Climate Modeling for Energy (ACME) effort, a project sponsored by the Earth System Modeling program within DOE's Office of Biological and Environmental Research. Currently, ACME collaborators are focused on developing an advanced climate model capable of simulating 80 years of historic and future climate variability and change in 3 weeks or less of computing effort.

Now in its third year, the project has achieved several milestones—notably the development of ACME version 1 and the successful inclusion of human factors in one of its component models, the iESM.

"What's unique about ACME is that it's pushing the system to a higher resolution than has been attempted before," Thornton said. "It's also pushing toward a more comprehensive simulation capability by including human dimensions and other advances, yielding the most detailed Earth system models to date.

The development of iESM started before the ACME initiative when a multilaboratory team aimed to add new human dimensions—such as how people affect the planet to produce and consume energy—to Earth system models. The model—now a part of the ACME human dimensions component—is being merged with ACME in preparation for ACME version 2.

ACME version 1 will be publicly released in late-2017 for analysis and use by other researchers. Results from the model will also contribute to the Coupled Model Intercomparison Project, which provides foundational material for climate change assessment reports."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on July 23, 2017, 04:20:22 PM
The linked reference projects substantial dynamical ocean response to projected changes in the global water cycle from RCP 8.5.  Just image how much response would occur due to freshwater hosing from Hansen's ice-climate feedback mechanism:

Xin Liu, Armin Köhl & Detlef Stammer (22 July 2017), "Dynamical ocean response to projected changes of the global water cycle", Journal of Geophysical Research Oceans, DOI: 10.1002/2017JC013061

http://onlinelibrary.wiley.com/doi/10.1002/2017JC013061/abstract?utm_content=buffere7420&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer (http://onlinelibrary.wiley.com/doi/10.1002/2017JC013061/abstract?utm_content=buffere7420&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer)

Abstract: "Over the next century substantial changes will occur in the ocean as a consequence of an accelerated global hydrological cycle and the associated net surface freshwater flux change is projected to result from global warming. This paper is concerned with the dynamical response to the associated surface volume flux anomalies. Based on ocean model runs driven by RCP8.5 surface freshwater flux anomalies over the period 2081-2100 relative to 1986-2005, we show that the adjustment of the circulation involves a barotropic circulation response as predicted from the Goldsbrough-Stommel theory. The corresponding barotropic circulation intensifies by approximately 20% with a stronger intensification of about 50% in the Southern Ocean, comparing to the present-day Goldsbrough-Stommel Circulation. The barotropic circulation anomaly induced by intensified freshwater flux reaches to 0.6 Sv in the Antarctic Circumpolar Current region. The adjustment also involves changes in the meridional overturning circulation mirroring the basin-wide averages of changes in the convergence and divergence of the mass transport driven by the surface volume flux. The subsequent pathways of fresh water match with the spreading of volume flux in the shallow cells but diverge substantially with depth. Associated with changes of the flow field are the changes in meridional heat and freshwater transports. Changes in the circulation also lead to a redistribution of temperature and salinity from which a significant contribution result in form of regional steric sea level changes. These changes are of the order of 0.5 cm and can be largely attributed to the displacement of the isopycnals."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on July 24, 2017, 05:43:26 PM
The linked reference indicates that extreme El Nino events could double in frequency if/when we reach a 1.5C increase in global mean surface temperature anom. relative to pre-industrial:

Guojian Wang, et. al. (2017), " Continued increase of extreme El Niño frequency long after 1.5 °C warming stabilization", Nature Climate Change, doi:10.1038/nclimate3351

http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate3351.html?foxtrotcallback=true (http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate3351.html?foxtrotcallback=true)

Abstract: "The Paris Agreement aims to constrain global mean temperature (GMT) increases to 2 °C above pre-industrial levels, with an aspirational target of 1.5 °C. However, the pathway to these targets and the impacts of a 1.5 °C and 2 °C warming on extreme El Niño and La Niña events—which severely influence weather patterns, agriculture, ecosystems, public health and economies—is little known. Here, by analysing climate models participating in the Climate Model Intercomparison Project’s Phase 5 (CMIP5) under a most likely emission scenario, we demonstrate that extreme El Niño frequency increases linearly with the GMT towards a doubling at 1.5 °C warming. This increasing frequency of extreme El Niño events continues for up to a century after GMT has stabilized, underpinned by an oceanic thermocline deepening that sustains faster warming in the eastern equatorial Pacific than the off-equatorial region. Ultimately, this implies a higher risk of extreme El Niño to future generations after GMT rise has halted. On the other hand, whereas previous research suggests extreme La Niña events may double in frequency under the 4.5 °C warming scenario, the results presented here indicate little to no change under 1.5 °C or 2 °C warming."

See also: "‘Extreme’ El Niños to double in frequency under 1.5C of warming, study says"

https://www.carbonbrief.org/extreme-el-ninos-double-frequency-under-one-point-five-celsius-warming-study (https://www.carbonbrief.org/extreme-el-ninos-double-frequency-under-one-point-five-celsius-warming-study)

Extract: "Now a new study, published in Nature Climate Change, suggests that similar “extreme” El Niño events could become more frequent as global temperatures rise.

If global warming reaches 1.5C above pre-industrial levels – the aspirational limit of the Paris Agreement – extreme El Niño events could happen twice as often, the researchers find.

That means seeing an extreme El Niño on average every 10 years, rather every 20 years."
Title: Re: Modelling the Anthropocene
Post by: rboyd on July 24, 2017, 10:45:20 PM
If I understand correctly, more frequent extreme El Nino events, with no increase in extreme La Nina, will act as a positive feedback. More periods of warm surface waters in the Pacific that exchange heat with the atmosphere, and El Nino related jumps in atmospheric carbon dioxide.

Only benefit would seem to be fewer hurricanes in the Atlantic.
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on July 25, 2017, 03:30:05 AM
If I understand correctly, more frequent extreme El Nino events, with no increase in extreme La Nina, will act as a positive feedback. More periods of warm surface waters in the Pacific that exchange heat with the atmosphere, and El Nino related jumps in atmospheric carbon dioxide.

Only benefit would seem to be fewer hurricanes in the Atlantic.

Concur, but more extreme El Ninos can also accelerate the degradation of the WAIS
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on July 27, 2017, 06:17:53 PM
The response of the ENSO cycle to continued global warming will be a key to effective ECS this century:

John T Bruun, J. Icarus Allen & Timothy J Smyth (26 July 2017), "Heartbeat of the Southern Oscillation explains ENSO climatic resonances", Journal of Geophysical Research Oceans, DOI: 10.1002/2017JC012892

http://onlinelibrary.wiley.com/doi/10.1002/2017JC012892/abstract?utm_content=buffer47acd&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer (http://onlinelibrary.wiley.com/doi/10.1002/2017JC012892/abstract?utm_content=buffer47acd&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer)

Abstract: "The El Niño–Southern Oscillation (ENSO) non-linear oscillator phenomenon has a far reaching influence on the climate and human activities. The upto 10 year quasi-period cycle of the El Niño and subsequent La Niña is known to be dominated in the tropics by non-linear physical interaction of wind with the equatorial wave-guide in the Pacific. Long term cyclic phenomena do not feature in the current theory of the ENSO process. We update the theory by assessing low (> 10 years) and high (< 10 years) frequency coupling using evidence across tropical, extratropical and Pacific basin scales. We analyse observations and model simulations with a highly accurate method called Dominant Frequency State Analysis (DFSA) to provide evidence of stable ENSO features. The observational datasets of the Southern Oscillation Index (SOI), North Pacific Index Anomaly and ENSO Sea Surface Temperature Anomaly, as well as a theoretical model all confirm the existence of long and short term climatic cycles of the ENSO process with resonance frequencies of {2.5, 3.8, 5, 12 to 14, 61 to 75, 180} years. This fundamental result shows long and short term signal coupling with mode locking across the dominant ENSO dynamics. These dominant oscillation frequency dynamics, defined as ENSO frequency states, contain a stable attractor with three frequencies in resonance allowing us to coin the term Heartbeat of the Southern Oscillation due to its characteristic shape. We predict future ENSO states based on a stable hysteresis scenario of short and long term ENSO oscillations over the next century.
Synopsis
The Pacific El Niño - Southern Oscillation (ENSO) non-linear oscillator phenomenon has a far reaching influence on the climate and our human activities. This work can help predict both long and short term future ENSO events and to assess the risk of future climate hysteresis changes: is the elastic band that regulates the ENSO climate breaking? We update the current theory of the ENSO process with a sophisticated analysis approach (Dominant Frequency State Analysis) to include long term oscillations (up to 200 years) as-well-as tropical and extra-tropical interaction dynamics. The analysis uses instrumental and paleo-proxy data records in combination with theoretical models of ENSO. This fundamental result that shows the ENSO phenomenon has a stable tropical Pacific attractor with El Niño and La Niña phases, tropical and extra-tropical coupling and an intermittency or longer term form of chaos. We call this attractor the Heartbeat of the Southern Oscillation as the phenomenon is measurable in the southern oscillation. We predict future ENSO states based on a stable hysteresis scenario of short and long term ENSO oscillations over the next century."
Title: Re: Modelling the Anthropocene
Post by: gerontocrat on July 27, 2017, 06:50:48 PM
If I understand correctly, more frequent extreme El Nino events, with no increase in extreme La Nina, will act as a positive feedback. More periods of warm surface waters in the Pacific that exchange heat with the atmosphere, and El Nino related jumps in atmospheric carbon dioxide.

Only benefit would seem to be fewer hurricanes in the Atlantic.
Is it correct to think that in al nina years cool surface water tends to increase heat transfer to the oceans, while in el nino years the ocean gives back some of that stored energy back to the atmosphere which releases that energy quickly into space?
If so, if one regards the oceans as the repository of 90+ percent of the excess energy trapped by atmospheric co2, then one could look at el nino years as giving some short-term relief from the inevitable heating of the planet.
Title: Re: Modelling the Anthropocene
Post by: rboyd on July 27, 2017, 10:43:42 PM
If I understand correctly, more frequent extreme El Nino events, with no increase in extreme La Nina, will act as a positive feedback. More periods of warm surface waters in the Pacific that exchange heat with the atmosphere, and El Nino related jumps in atmospheric carbon dioxide.

Only benefit would seem to be fewer hurricanes in the Atlantic.
Is it correct to think that in al nina years cool surface water tends to increase heat transfer to the oceans, while in el nino years the ocean gives back some of that stored energy back to the atmosphere which releases that energy quickly into space?
If so, if one regards the oceans as the repository of 90+ percent of the excess energy trapped by atmospheric co2, then one could look at el nino years as giving some short-term relief from the inevitable heating of the planet.

Assume that you mean La Nina years for giving short-term relief, only to the atmosphere; not the planet as a whole, which includes the oceans. The more heat in the oceans, the more land ice melting, the less CO2 it can take up, the more anoxic ... So may be a case of how you want your poison.
Title: Re: Modelling the Anthropocene
Post by: gerontocrat on July 27, 2017, 11:15:57 PM
I meant el  nino gives the short-term relief. You are right, it is a question of which poison will administer the coup de grace.
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on August 01, 2017, 04:33:43 AM
For those who are interested:

Ghil, Michael. 2017. “The wind-driven ocean circulation: Applying dynamical systems theory to a climate problem.” Discrete and Continuous Dynamical Systems - A 37 (1): 189-228.

https://dept.atmos.ucla.edu/sites/default/files/tcd/files/ghil-2_gyrerds-dcds_a-2016.pdf?m=1472775833


Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on August 01, 2017, 10:55:43 PM
In additional to working to improve model accuracy, the linked reference finds that the width of the Hadley Cell increases nonlinearly with surface temperature gradients:

Sonja Molnos, Stefan Petri, Jascha Lehmann, Erik Peukert, Dim Coumou (2017), "The sensitivity of the large-scale atmosphere circulation to changes in surface temperature gradients in the Northern Hemisphere", Earth Syst. Dynam. Discuss., https://doi.org/10.5194/esd-2017-65 (https://doi.org/10.5194/esd-2017-65)

https://www.earth-syst-dynam-discuss.net/esd-2017-65/esd-2017-65.pdf (https://www.earth-syst-dynam-discuss.net/esd-2017-65/esd-2017-65.pdf)

Abstract: "Climate and weather conditions in the mid-latitudes are strongly driven by the large-scale atmosphere circulation.  Observational data indicates that important components of the large-scale circulation have changed in recent decades including the strength of the Hadley cell, jet streams, storm tracks and planetary waves. Associated impacts cover a broad range, including changes in the frequency and nature of weather extremes and shifts of fertile habitats with implications for biodiversity and agriculture. Dynamical theories have been proposed that link the shift of the poleward edge of the Northern Hadley cell to changes in the meridional temperature gradient. Moreover, model simulations have been carried out to analyse the cause of observed and projected changes in the large-scale atmosphere circulation. However, the question of the underlying drivers and particularly the possible role of global warming is still debated. Here, we use a statistical-dynamical atmosphere model (SDAM) to analyse the sensitivity of the Northern Hemisphere Hadley cell, storm tracks, jet streams and planetary waves to changes in temperature fields by systematically altering the zonal and meridional temperature gradient as well as the global mean surface temperature.

SDAMs are computationally fast compared to more complex general circulation models (GCM) which enables us to scan a large and high-dimensional parameter space for sensitivity analyses using more than thousand individual model runs.

Our results show that the strength of the Hadley cell, storm tracks and jet streams depends almost linearly on both the global mean temperature and the meridional temperature gradient whereas the zonal temperature gradient has little or no influence.  The magnitude of planetary waves is clearly affected by all three temperature components. Finally, the width of the Hadley cell behaves nonlinearly with respect to all three temperature components.

Under global warming the meridional temperature gradient is expected to change: Enhanced warming is expected in the Arctic, largely near the surface, and at the equator at high altitudes. Also there is a pronounced seasonality to these warming patterns. Using SDAMs to disentangle and separately analyse the effect of individual temperature changes might thus help to understand observed and projected changes in large-scale atmosphere dynamics."

Extract: "In contrast, our results indicate that the width of the Hadley cell generally increases nonlinearly with increasing zonal and meridional temperature gradient. If land masses warm up faster than oceans, the width of the Hadley cell might change in those land areas and that would have an influence on the zonal mean Hadley cell as well."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on August 02, 2017, 01:20:49 AM
The linked reference examines the case where freshwater hosing effectively shuts-down the AMOC (as in Hansen's ice-climate feedback mechanism); and finds that the ENSO mores to towards the Eastern Pacific; which I note is typically an indication of increased effective ECS:

Mark S. Williamson, Mat Collins, Sybren S. Drijfhout, Ron Kahana, Jennifer V. Mecking and Timothy M. Lenton (2017), "Effect of AMOC collapse on ENSO in a high resolution general circulation model", Climate Dynamics, DOI: 10.1007/s00382-017-3756-0

https://link.springer.com/article/10.1007/s00382-017-3756-0

Abstract: "We look at changes in the El Niño Southern Oscillation (ENSO) in a high-resolution eddy-permitting climate model experiment in which the Atlantic Meridional Circulation (AMOC) is switched off using freshwater hosing. The ENSO mode is shifted eastward and its period becomes longer and more regular when the AMOC is off. The eastward shift can be attributed to an anomalous eastern Ekman transport in the mean equatorial Pacific ocean state. Convergence of this transport deepens the thermocline in the eastern tropical Pacific and increases the temperature anomaly relaxation time, causing increased ENSO period. The anomalous Ekman transport is caused by a surface northerly wind anomaly in response to the meridional sea surface temperature dipole that results from switching the AMOC off. In contrast to a previous study with an earlier version of the model, which showed an increase in ENSO amplitude in an AMOC off experiment, here the amplitude remains the same as in the AMOC on control state. We attribute this difference to variations in the response of decreased stochastic forcing in the different models, which competes with the reduced damping of temperature anomalies. In the new high-resolution model, these effects approximately cancel resulting in no change in amplitude."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on August 02, 2017, 03:53:46 AM
While the reference is seeking to establish Stokes Ice Sheet Models as the standard of comparison (say for inclusion in ACME), it does not consider such import mechanisms as cliff failures and hydrofracturing:

Zhang T, Price SF, Ju L, et al. (2017), "A Comparison of Two Stokes Ice Sheet Models Applied to the Marine Ice Sheet Model Intercomparison Project for Plan View Models (MISMIP3d).", DOI: 10.5194/tc-11-179-2017

https://climatemodeling.science.energy.gov/research-highlights/comparison-stokes-ice-sheet-models-marine-ice-sheet-experiments

Summary: “Stokes-flow ice sheet models are commonly used to generate solutions of reference for ice sheet model intercomparison test cases. These test cases are critical for informal validation of ice sheet models as applied to particular ice dynamical problems of interest (e.g., grounding line motion) and for testing the accuracy of computationally cheaper, and numerically less complex "shallow" approximations to the Stokes-flow equations of motion. To date, a single model, Elmer-Ice, has been used by the community for generating these reference solutions. In this work, we conduct a detailed comparison between Elmer-Ice and a second Stokes model, FELIX-S, as applied to a set of marine-ice sheet model benchmark test cases. We show that, despite significant differences in methodologies between the two models, the two sets of model solutions converge with increasing grid resolution, as expected. This lends confidence to the practice of treating Stokes model solutions as reference solutions in model intercomparison exercises.”
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on August 09, 2017, 06:09:41 PM
The linked reference uses model projections to demonstrate that relatively large and rapid obduction (re-emergence) of anthropogenic carbon into the well-mixed surface layer in the ocean will contribute to limiting of future ocean uptake of carbon from the atmosphere.  This is not good news:

Katsuya Toyama et. al. (2017), "Large Re-emergence of Anthropogenic Carbon Into the Ocean’s Surface Mixed Layer Sustained by the Ocean’s Overturning Circulation", Journal of Climate, https://doi.org/10.1175/JCLI-D-16-0725.1 (https://doi.org/10.1175/JCLI-D-16-0725.1)

http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-16-0725.1?utm_content=buffer00f0c&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer (http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-16-0725.1?utm_content=buffer00f0c&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer)

Abstract: "We evaluate the output from a widely used ocean carbon cycle model to identify the subduction and obduction (re-emergence) rates of anthropogenic carbon (Cant) for climatological conditions during the World Ocean Circulation Experiment (WOCE) era in 1995 using a new set of Lagrangian diagnostic tools. The principal scientific value of the Lagrangian diagnostics is in providing a new means to connect Cant re-emergence pathways to the relatively rapid renewal timescales of mode waters through the overturning circulation.

Our main finding is that for this model with 2.04 PgC/yr of uptake of Cant via gas exchange, the subduction and obduction rates across the base of the mixed layer (MLbase) are 4.96 PgC/yr and 4.50 PgC/yr, respectively, which are twice as large as the gas exchange at the surface. Given that there is net accumulation of 0.17 PgC/yr in the mixed layer itself, this implies the residual downward Cant transport of 1.40 PgC/yr across the MLbase is associated with diffusion. Importantly, the net patterns for subduction and obduction transports of Cant mirror the large-scale patterns for transport of water volume, thereby illustrating the processes controlling Cant uptake. Although the net transfer across the MLbase by compensating subduction and obduction is relatively smaller than the diffusion, localized pattern of Cant subduction and obduction implies significant regional impacts. The median timescale for re-emergence of obducting particles is short (less than 10 years), indicating that re-emergence should contribute to limiting future carbon uptake through its contribution to perturbing the Revelle factor for surface waters."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on August 15, 2017, 04:37:36 PM
The linked reference confirms that the primary parameter that controls the poleward expansion of the Hadley Cell circulation is the increase in Global Mean Surface Temperature Anom. (GMSTA):

Roberta D'Agostino, Piero Lionello, Ori Adam & Tapio Schneider (14 August 2017), "Factors controlling Hadley circulation changes from the Last Glacial Maximum to the end of the 21st century", Geophysical Research Letters, DOI: 10.1002/2017GL074533 

http://onlinelibrary.wiley.com/doi/10.1002/2017GL074533/abstract?utm_content=buffer39a58&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer (http://onlinelibrary.wiley.com/doi/10.1002/2017GL074533/abstract?utm_content=buffer39a58&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer)

Abstract: "The Hadley circulation (HC) extent and strength are analyzed in a wide range of simulated climates from the last glacial maximum to global-warming scenarios. Motivated by HC theories, we analyze how the HC is influenced by the subtropical stability, the near-surface meridional potential temperature gradient, and the tropical tropopause level. The subtropical static stability accounts for the bulk of the HC changes across the simulations. However, since it correlates strongly with global-mean surface temperature, most HC changes can be attributed to global-mean surface temperature changes. The HC widens as the climate warms, and it also weakens, but only robustly so in the northern hemisphere. On the other hand, the southern hemisphere strength response is uncertain, in part because subtropical static stability changes counteract meridional potential temperature gradient changes to various degrees in different models, with no consensus on the response of the latter to global warming."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on August 18, 2017, 10:48:05 PM
The linked reference discusses mixed-phase altocumulus cloud feedback.

Andrew I. Barrett et. al. (17 August 2017), "Why are mixed-phase altocumulus clouds poorly predicted by large-scale models? Part II: Vertical resolution sensitivity and parameterization", Journal of Geophysical Research Atmospheres, DOI: 10.1002/2016JD026322

http://onlinelibrary.wiley.com/doi/10.1002/2016JD026322/abstract?utm_content=buffer64ee3&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer (http://onlinelibrary.wiley.com/doi/10.1002/2016JD026322/abstract?utm_content=buffer64ee3&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer)

Abstract: "Single-column model simulations of mixed-phase altocumulus clouds were shown to have a strong vertical-resolution sensitivity in Part I of this paper. Coarse resolution models were unable to simulate the long-lived supercooled-liquid-layer at cloud top, typically only 200-m thick. In this paper, the sensitivity to vertical resolution is investigated using idealized simulations. Vertical gradients of ice water mixing ratio and temperature near cloud top are found to be inadequately represented at coarse-resolution. The vertical discretization using grid-box mean values, rather than the full vertical profile, leads to biased calculations of mixed-phase microphysical process rates and affects the diagnosis of thin liquid-water layers. As a result the liquid-water layer becomes quickly glaciated and altocumulus cloud lifetime is underestimated. Similar impacts are expected for mixed-phase boundary layer clouds commonly observed at high latitudes.

A novel parameterization is introduced that accounts for the vertical gradients of ice water mixing ratio and temperature in the microphysics calculations and the diagnosis of liquid near cloud top. It substantially improves the representation of altocumulus layers in coarse vertical-resolution single-column model simulations and reduces the bias identified in Part I. The new parameterization removes the large underestimate in supercooled water content caused by the resolution sensitivity for temperatures warmer than −30∘C. Given the radiative importance of mixed-phase altocumulus clouds, their underestimation by numerical weather prediction models and their potential to act as a negative climate feedback, there is a need to re-evaluate the global climate sensitivity by implementing the findings in these two papers in a climate model."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on August 19, 2017, 05:46:51 PM
I provide the following links as a follow-on to Replies #132 &133; and while I applaud the general goal of directly coupling large-scale models of human activity with a complex Earth Systems model to produce an integrated Earth System Model, iESM; nevertheless, below I elaborate on some of my concerns that I began to express in Reply #133:

1. In Reply #133 I expressed concerns about the strong likelihood of a failure of leadership under a Rick Perry led DOE for the ACME iESM.  In that Reply, I expressed strong concerns that the effectiveness of BECCS would be oversold, and here I also say that other geoengineering solutions (particularly solar dimming and cloud manipulation) are equally likely to be oversold.

2. I doubt that ACME version 2 (with iESM) will adequately represent the true nonlinear nature of ECS this century and thus will likely underestimate future temperatures.  Additionally, I suspect that recent research findings indicating high ECS values in paleo times will either be discounted and/or misinterpreted.

3. I doubt the likely coming unmaskings of numerous factors that have been masking true climate sensitivity in the observed record will be modeled correctly.

4. I doubt that the modeling of human activities will represent reality.

Title: "Titan simulations show importance of close two-way coupling between human and Earth systems"

https://www.sciencedaily.com/releases/2017/07/170718131042.htm (https://www.sciencedaily.com/releases/2017/07/170718131042.htm)

Extract: "By using supercomputers such as the Oak Ridge Leadership Computing Facility's Titan, a large multidisciplinary team of scientists developed a new integrated climate model designed to reduce uncertainties in future climate predictions as it bridges Earth systems with energy and economic models and large-scale human impact data.

To inform its Earth system models, the climate modeling community has a long history of using integrated assessment models -- frameworks for describing humanity's impact on Earth, including the source of global greenhouse gases, land use and land cover change, and other resource-related drivers of anthropogenic climate change.

Until now, researchers had not been able to directly couple large-scale human activity with an Earth system model. In fact, the novel iESM could mark a new era of complex and comprehensive modeling that reduces uncertainty by incorporating immediate feedbacks to socioeconomic variables for more consistent predictions.

The development of iESM started before the ACME initiative when a multilaboratory team aimed to add new human dimensions -- such as how people affect the planet to produce and consume energy -- to Earth system models. The model -- now a part of the ACME human dimensions component -- is being merged with ACME in preparation for ACME version 2."

See also:

https://github.com/ACME-Climate/iESM (https://github.com/ACME-Climate/iESM)

&

http://www.globalchange.umd.edu/iesm/ (http://www.globalchange.umd.edu/iesm/)
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on August 22, 2017, 05:51:50 PM
The linked references discusses the level of modeling effort recommended to reduce uncertainty of projecting future changes in the ENSO due to internal variability:

Xiao-Tong Zheng, Chang Hui & Sang-Wook Yeh (2017), "Response of ENSO amplitude to global warming in CESM large ensemble: uncertainty due to internal variability", Climate Dynamics, pp 1–17, https://doi.org/10.1007/s00382-017-3859-7

https://rd.springer.com/article/10.1007%2Fs00382-017-3859-7?utm_content=bufferc17f2&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer

Abstract: "El Niño–Southern Oscillation (ENSO) is the dominant mode of variability in the coupled ocean-atmospheric system. Future projections of ENSO change under global warming are highly uncertain among models. In this study, the effect of internal variability on ENSO amplitude change in future climate projections is investigated based on a 40-member ensemble from the Community Earth System Model Large Ensemble (CESM-LE) project. A large uncertainty is identified among ensemble members due to internal variability. The inter-member diversity is associated with a zonal dipole pattern of sea surface temperature (SST) change in the mean along the equator, which is similar to the second empirical orthogonal function (EOF) mode of tropical Pacific decadal variability (TPDV) in the unforced control simulation. The uncertainty in CESM-LE is comparable in magnitude to that among models of the Coupled Model Intercomparison Project phase 5 (CMIP5), suggesting the contribution of internal variability to the intermodel uncertainty in ENSO amplitude change. However, the causations between changes in ENSO amplitude and the mean state are distinct between CESM-LE and CMIP5 ensemble. The CESM-LE results indicate that a large ensemble of ~15 members is needed to separate the relative contributions to ENSO amplitude change over the twenty-first century between forced response and internal variability."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on August 31, 2017, 06:20:52 PM
The linked reference uses a climate model to help quantify the impact of "Earth greening" on global warming & found that global land-surface warming was decreased by about 12% (over the past 30 years) due to this consideration.  This makes me wonder what will happen if/when "Earth greening" moves in the negative direction due to climate and land use stresses on vegetation:

Zhenzhong Zeng et. al. (2017), "Climate mitigation from vegetation biophysical feedbacks during the past three decades", Nature Climate Change  7, 432–436, doi:10.1038/nclimate3299

http://www.nature.com/nclimate/journal/v7/n6/full/nclimate3299.html?foxtrotcallback=true (http://www.nature.com/nclimate/journal/v7/n6/full/nclimate3299.html?foxtrotcallback=true)

Abstract: "The surface air temperature response to vegetation changes has been studied for the extreme case of land-cover change; yet, it has never been quantified for the slow but persistent increase in leaf area index (LAI) observed over the past 30 years (Earth greening). Here we isolate the fingerprint of increasing LAI on surface air temperature using a coupled land–atmosphere global climate model prescribed with satellite LAI observations. We find that the global greening has slowed down the rise in global land-surface air temperature by 0.09 ± 0.02 °C since 1982. This net cooling effect is the sum of cooling from increased evapotranspiration (70%), changed atmospheric circulation (44%), decreased shortwave transmissivity (21%), and warming from increased longwave air emissivity (−29%) and decreased albedo (−6%). The global cooling originated from the regions where LAI has increased, including boreal Eurasia, Europe, India, northwest Amazonia, and the Sahel. Increasing LAI did not, however, significantly change surface air temperature in eastern North America and East Asia, where the effects of large-scale atmospheric circulation changes mask local vegetation feedbacks. Overall, the sum of biophysical feedbacks related to the greening of the Earth mitigated 12% of global land-surface warming for the past 30 years."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on September 12, 2017, 10:16:39 PM
The linked comparison study provides insights into issues such as those raised by Sherwood et al (2014).  While the reference makes no definitive conclusions, it does highlight the importance of correctly modeling slow response feedback mechanisms associated with the ocean heat uptake (particularly in the (Equatorial Pacific) since 1750:

Kuan-Man Xu et al (9 September 2017), "Differences in the hydrological cycle and sensitivity between multiscale modeling frameworks with and without a higher-order turbulence closure", JAMES, DOI: 10.1002/2017MS000970

http://onlinelibrary.wiley.com/doi/10.1002/2017MS000970/full (http://onlinelibrary.wiley.com/doi/10.1002/2017MS000970/full)

Abstract: "Current conventional global climate models (GCMs) produce a weak increase in global-mean precipitation with anthropogenic warming in comparison with the lower tropospheric moisture increases. The motive of this study is to understand the differences in the hydrological sensitivity between two multiscale modeling frameworks (MMFs) that arise from the different treatments of turbulence and low clouds in order to aid to the understanding of the model spread among conventional GCMs. We compare the hydrological sensitivity and its energetic constraint from MMFs with (SPCAM-IPHOC) or without (SPCAM) an advanced higher-order turbulence closure. SPCAM-IPHOC simulates higher global hydrological sensitivity for the slow response but lower sensitivity for the fast response than SPCAM. Their differences are comparable to the spreads of conventional GCMs. The higher sensitivity in SPCAM-IPHOC is associated with the higher ratio of the changes in latent heating to those in net atmospheric radiative cooling, which is further related to a stronger decrease in the Bowen ratio with warming than in SPCAM. The higher sensitivity of cloud radiative cooling resulting from the lack of low clouds in SPCAM is another major factor in contributing to the lower precipitation sensitivity. The two MMFs differ greatly in the hydrological sensitivity over the tropical lands, where the simulated sensitivity of surface sensible heat fluxes to surface warming and CO2 increase in SPCAM-IPHOC is weaker than in SPCAM. The difference in divergences of dry static energy flux simulated by the two MMFs also contributes to the difference in land precipitation sensitivity between the two models."

Edit, see also:

Sherwood, S.C., Bony, S. and Dufresne, J.-L., (2014) "Spread in model climate sensitivity traced to atmospheric convective mixing", Nature; Volume: 505, pp 37–42, doi:10.1038/nature12829

http://www.nature.com/nature/journal/v505/n7481/full/nature12829.html (http://www.nature.com/nature/journal/v505/n7481/full/nature12829.html)

Fasullo, J.T. and Trenberth, K.E., (2012), "A Less Cloudy Future: The Role of Subtropical Subsidence in Climate Sensitivity", Science, vol. 338, pp. 792-794, 2012. http://dx.doi.org/10.1126/science.1227465. (http://dx.doi.org/10.1126/science.1227465.)

http://www.sciencemag.org/content/338/6108/792 (http://www.sciencemag.org/content/338/6108/792)
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on September 12, 2017, 10:44:09 PM
The unusually high Pacific trade winds in recent decades is frequently associated with the faux hiatus; and the linked reference discusses bias in CMIP5 projections that resulted in under-predictions of the strength of these Pacific trade winds during the faux hiatus.

Jules B. Kajtar, Agus Santoso, Shayne McGregor, Matthew H. England & Zak Baillie (2017), "Model under-representation of decadal Pacific trade wind trends and its link to tropical Atlantic bias", Climate Dynamics", doi:10.1007/s00382-017-3699-5

https://link.springer.com/article/10.1007/s00382-017-3699-5

Abstract: "The strengthening of the Pacific trade winds in recent decades has been unmatched in the observational record stretching back to the early twentieth century. This wind strengthening has been connected with numerous climate-related phenomena, including accelerated sea-level rise in the western Pacific, alterations to Indo-Pacific ocean currents, increased ocean heat uptake, and a slow-down in the rate of global-mean surface warming. Here we show that models in the Coupled Model Intercomparison Project phase 5 underestimate the observed range of decadal trends in the Pacific trade winds, despite capturing the range in decadal sea surface temperature (SST) variability. Analysis of observational data suggests that tropical Atlantic SST contributes considerably to the Pacific trade wind trends, whereas the Atlantic feedback in coupled models is muted. Atmosphere-only simulations forced by observed SST are capable of recovering the time-variation and the magnitude of the trade wind trends. Hence, we explore whether it is the biases in the mean or in the anomalous SST patterns that are responsible for the under-representation in fully coupled models. Over interannual time-scales, we find that model biases in the patterns of Atlantic SST anomalies are the strongest source of error in the precipitation and atmospheric circulation response. In contrast, on decadal time-scales, the magnitude of the model biases in Atlantic mean SST are directly linked with the trade wind variability response."
Title: Re: Modelling the Anthropocene
Post by: 6roucho on September 13, 2017, 08:14:04 PM
AnruptSLR, how do you read so much and so widely? You're a machine!
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on September 14, 2017, 04:22:32 PM
AnruptSLR, how do you read so much and so widely? You're a machine!

As noted in the Adapting to the Anthropocene thread, by "... the recursive application of: deductive logic, inductive logic, the reduction of entropy, concentration/focus/effort/work and letting go of preconditioning ... "
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on September 19, 2017, 07:58:38 PM
Given the complex nature of climate change, I think that CMIP6 and similarly future modeling efforts would do well to follow the advice given in the linked reference to combine "… dynamical modeling with data-driven methodological approaches (i.e., neural networks and Granger causality) …".

Fulvio Mazzocchi & Antonello Pasini (31 May 2017), "Climate model pluralism beyond dynamical ensembles", Wires: Climate Change, DOI: 10.1002/wcc.477

http://onlinelibrary.wiley.com/doi/10.1002/wcc.477/full (http://onlinelibrary.wiley.com/doi/10.1002/wcc.477/full)

Abstract: "Using pluralist research strategies can be a profitable way to study complex systems. This contribution focuses on the approaches for studying the climate that make use of multiple different models, aiming to increase the reliability (in terms of robustness) of attribution results. This Opinion article argues that the traditional approach, which is based on ensemble runs of global climate models, only partially allows the application of a robustness scheme, owing to the difficulty to match or evaluate the conditions required for robustness (i.e., independence or heterogeneity among models). An alternative ‘multi-approach’ strategy is advanced, beyond dynamical modeling but still preserving the idea of model pluralism. Such a strategy, which uses a set of ensembles of different model types by combining dynamical modeling with data-driven methodological approaches (i.e., neural networks and Granger causality), seems to better match the condition of independence. In addition, neural networks and Granger causality lead to achievements in attribution studies that can complement those obtained by dynamical modeling."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on September 29, 2017, 03:40:48 PM
The linked opinion piece describes actual and proposed systemic changes to CESM made in an effort to try to help modelers to gain a better understanding of the various Earth's Systems.  If this is done with sincerity it is a good idea; however, if managers/policy makers see that this affords them an opportunity to put their collective thumb on the modeling process/outcome then it is a bad idea:

Title: "When Less Is More: Opening the Door to Simpler Climate Models"

https://eos.org/opinions/when-less-is-more-opening-the-door-to-simpler-climate-models?utm_source=eos&utm_medium=email&utm_campaign=EosBuzz092917

Extract: "Earth system models are resource intensive and complex. To cut through this complexity, the Community Earth System Model project will now be embracing a hierarchy of simpler climate models.

In a nutshell, ESMs may be good for simulating the climate system but may not be as valuable for understanding it. So we have now added a new set of tools within the Community Earth System Model (CESM) project: a hierarchy of simpler models to foster this understanding. Specifically, we are happy to announce that the next version of CESM will include two simple atmospheric models: a “dynamical core” and an “aquaplanet.”

We conclude by emphasizing one crucial point in Held’s proposal: Models in the hierarchy must be of lasting value. ESMs are constantly under development to promptly incorporate the latest findings or methods. However, we believe that at least some of the models in the hierarchy need to be forcefully shielded from the relentless cycle of model improving and updating. If those models are well chosen, their value will come precisely from the fact that they are not being updated. Because they remain unchanged, we will be able to understand them in great depth and thus close the gap between simulation and understanding—the ultimate motivation of this entire exercise."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on September 30, 2017, 06:23:48 PM
The linked reference examines the output from CMIP5 projections to better differentiate between fast and slow components of the extratropical atmospheric circulation response to stepped radiative forcing.  I note that CMIP5 does not consider hosing from ice sheet mass loss & thus does not consider ice-climate feedback.  Nevertheless, the findings do indicate: (1) a fast response within 5 to 10 years of the stepped forcing; (2) an increase in ENSO activity (& increase in associated positive feedback mechanisms); and (3) an increase in Antarctic Amplification.  Hopefully, CMIP6 will consider freshwater hosing and ice-climate feedback.

Paulo Ceppi, Giuseppe Zappa, and Theodore G. Shepherd (28 September 2017), "Fast and slow components of the extratropical atmospheric circulation response to CO2 forcing", Journal of Climate, https://doi.org/10.1175/JCLI-D-17-0323.1 (https://doi.org/10.1175/JCLI-D-17-0323.1)

http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-17-0323.1?utm_content=buffer2cb5c&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer (http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-17-0323.1?utm_content=buffer2cb5c&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer)

Abstract: "Poleward shifts of the extratropical atmospheric circulation are a common response to CO2 forcing in global climate models (GCMs), but little is known about the time dependence of this response. Here it is shown that in coupled climate models, the long-term evolution of sea surface temperatures (SSTs) induces two distinct time scales of circulation response to step-like CO2 forcing. In most Coupled Model Intercomparison Project phase 5 GCMs as well as in the multi-model mean, all of the poleward shift of the midlatitude jets and Hadley cell edge occurs in a fast response within 5 to 10 years of the forcing, during which less than half of the expected equilibrium warming is realized. Compared with this fast response, the slow response over subsequent decades to centuries features stronger polar amplification (especially in the Antarctic), enhanced warming in the Southern Ocean, an El Niño-like pattern of tropical Pacific warming, and weaker land-sea contrast. Atmosphere-only GCM experiments demonstrate that the SST evolution drives the difference between the fast and slow circulation responses, although the direct radiative effect of CO2 also contributes to the fast response. It is further shown that the fast and slow responses determine the long-term evolution of the circulation response to warming in the RCP4.5 scenario. The results imply that shifts in midlatitude circulation generally scale with the radiative forcing, rather than with global-mean temperature change. A corollary is that time slices taken from a transient simulation at a given level of warming will considerably overestimate the extratropical circulation response in a stabilized climate."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on October 06, 2017, 06:49:20 PM
The linked article recommends that future climate change projections should account for the effects of future volcanic eruptions, and I note that this should include the eruption of halogen emitting volcanoes in the WAIS:

Title: "5 links between erupting volcanoes and climate change"

https://www.eenews.net/stories/1060062893 (https://www.eenews.net/stories/1060062893)

Extract: "The effects of volcanoes need to be accounted for in future climate change predictions, according to a study published in August in Nature Climate Change. As researchers make future predictions from climate models, they need to factor in major eruptions over the next century, said Ed Hawkins, a climatologist at the University of Reading. To accurately forecast how climate change will transform the planet, researchers must account for temporary periods of cooling that come from volcanoes, according to Hawkins.

"Including some eruptions makes the changes in global temperature more variable, but as the effects of eruptions are only temporary they will not counteract the warming from greenhouse gases over the next century," he wrote in an email."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on October 06, 2017, 08:46:27 PM
The former ACME project is now the Energy Exascale Earth System Model (E3SM) Project

Title: "Energy Exascale Earth System Model"

https://climatemodeling.science.energy.gov/projects/energy-exascale-earth-system-model

Extract: "The Energy Exascale Earth System Model (E3SM) project, previously known as ACME, is central to ESM as well as many of the Climate and Environmental Sciences Division activities, as it is developing a computationally advanced coupled climate-energy model to investigate the challenges posed by the interactions of weather-climate scale variability with energy and related sectors. The E3SM model simulates the fully coupled Earth system at high-resolution (15-25km, including higher resolution within regionally refined areas) and is incorporating coupling with energy, water, land-use and related energy-relevant activities, with a focus on near-term hind-casts (1970-2015) for model validation and a near-term projection (2015-2050) as needed for energy sector planning."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on October 15, 2017, 06:00:03 PM
While the linked reference's study of an Earth-like terra-planet may be of somewhat academic interest for newly discovered planets, the authors do note its possible relevance to an imaginary drop from present day conditions to the Snowball Earth state:

Kalidindi, S., Reick, C. H., Raddatz, T., and Claussen, M.: Two drastically different climate states on an Earth-like terra-planet, Earth Syst. Dynam. Discuss., https://doi.org/10.5194/esd-2017-84, (https://doi.org/10.5194/esd-2017-84,) in review, 2017.

https://www.earth-syst-dynam-discuss.net/esd-2017-84/ (https://www.earth-syst-dynam-discuss.net/esd-2017-84/)

Abstract. We study an Earth-like terra-planet with an overland recycling mechanism bringing fresh water back from higher latitudes to the lower latitudes. By performing model simulations for such a planet we find two drastically different climate states for the same set of boundary conditions and parameter values: A Cold and Wet (CW) state (present-day Earth-like climate) with dominant low-latitude precipitation and, a Hot and Dry (HD) state with only high-latitude precipitation. We notice that for perpetual equinox conditions, both climate states are stable below a certain threshold value of background soil albedo while above the threshold only the CW state is stable. Starting from the HD state and increasing background soil albedo above the threshold causes an abrupt shift from the HD state to the CW state resulting in a sudden cooling of about 35 °C globally which is of the order of the temperature difference between the present-day and the Snowball Earth state. In contrast to the Snowball Earth instability, we find that the sudden cooling in our study is driven by the cloud albedo feedback rather than the snow-albedo feedback. Also, when albedo in the CW state is reduced back to zero the terra-planet does not display a closed hysteresis. This is due to the high cloud cover in the CW state hiding the surface from solar irradiation. As a result, this reduction of background surface albedo has only a minor effect on the top of the atmosphere radiation balance, thereby making it impossible to heat the planet sufficiently strongly to switch back to the HD state. Additional simulations point to a similar abrupt transition from HD state to the CW state for non-zero obliquity which is the only stable state in this configuration. Our study also has implications for the habitability of Earth-like terra-planets. At the inner edge of the habitable zone, the higher cloud cover in the CW state cools the planet and may prevent the onset of a runaway greenhouse state. At the outer edge, the resupply of water at lower latitudes stabilizes the greenhouse effect and keeps the planet in the HD state and may prevent water from getting trapped at higher latitudes in frozen form. Overall, the existence of bi-stability in the presence of an overland recycling mechanism hints at the possibility of a wider habitable zone for Earth-like terra-planets at lower obliquities.
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on October 16, 2017, 01:32:36 AM
The linked reference discusses a climate model of intermediate sophistication that represents an initial effort to model Earth Systems subject to changing from on climate state to another due to periodic climate attractors:

Valerio Lucarini and Tamás Bódai (2017), "Edge states in the climate system: exploring global instabilities and critical transitions", Nonlinearity 30 R32, https://doi.org/10.1088/1361-6544/aa6b11 (https://doi.org/10.1088/1361-6544/aa6b11)

http://iopscience.iop.org/article/10.1088/1361-6544/aa6b11/meta (http://iopscience.iop.org/article/10.1088/1361-6544/aa6b11/meta)

Abstract: "Multistability is a ubiquitous feature in systems of geophysical relevance and provides key challenges for our ability to predict a system's response to perturbations. Near critical transitions small causes can lead to large effects and—for all practical purposes—irreversible changes in the properties of the system. As is well known, the Earth climate is multistable: present astronomical and astrophysical conditions support two stable regimes, the warm climate we live in, and a snowball climate characterized by global glaciation. We first provide an overview of methods and ideas relevant for studying the climate response to forcings and focus on the properties of critical transitions in the context of both stochastic and deterministic dynamics, and assess strengths and weaknesses of simplified approaches to the problem. Following an idea developed by Eckhardt and collaborators for the investigation of multistable turbulent fluid dynamical systems, we study the global instability giving rise to the snowball/warm multistability in the climate system by identifying the climatic edge state, a saddle embedded in the boundary between the two basins of attraction of the stable climates. The edge state attracts initial conditions belonging to such a boundary and, while being defined by the deterministic dynamics, is the gate facilitating noise-induced transitions between competing attractors. We use a simplified yet Earth-like intermediate complexity climate model constructed by coupling a primitive equations model of the atmosphere with a simple diffusive ocean. We refer to the climatic edge states as Melancholia states and provide an extensive analysis of their features. We study their dynamics, their symmetry properties, and we follow a complex set of bifurcations. We find situations where the Melancholia state has chaotic dynamics. In these cases, we have that the basin boundary between the two basins of attraction is a strange geometric set with a nearly zero codimension, and relate this feature to the time scale separation between instabilities occurring on weather and climatic time scales. We also discover a new stable climatic state that is similar to a Melancholia state and is characterized by non-trivial symmetry properties."
Title: Re: Modelling the Anthropocene
Post by: Adam Ash on October 26, 2017, 09:43:29 PM

Burial-induced oxygen-isotope re-equilibration of fossil foraminifera explains ocean paleotemperature paradoxes
https://www.nature.com/articles/s41467-017-01225-9 (https://www.nature.com/articles/s41467-017-01225-9)

According to the current methodology, the temperature of the ocean depths, and the surface of the polar ocean, was some 15C (59F) higher 100 million years ago, compared to now.

These estimates have been challenged, however, by a joint team of researchers from the French National Center for Scientific Research (CNRS) and the Swiss Federal Institute of Technology in Lausanne (EPFL).

In their study, published in Nature Communications, the team posits that ocean temperatures may have remained relatively stable throughout this period, raising serious concerns about the current level of climate change being experienced by Mother Earth.
Title: Re: Modelling the Anthropocene
Post by: sidd on October 27, 2017, 12:01:01 AM
If that Bernard paper holds up, it answers the question as to why the polar oceans in Cretaceous and Paleogene were so much warmer. The answer is that they were not, and the equator to pole gradient was larger than supposed.

"Furthermore, the present study suggests that the vertical and latitudinal temperature gradients of the late Cretaceous and Paleogene oceans were likely not very different from the current ones."

Fig 4 tells the story. I attach.

sidd
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on October 27, 2017, 03:13:24 PM
Tropical-Extratropical telecommunications (particularly w.r.t. ENSO patterns) are of fundamental importance for understanding numerous feedback mechanisms including Arctic Amplification and Hansen's ice-climate feedback (especially w.r.t. WAIS stability):

Cristiana Stan, David M. Straus, Jorgen S. Frederiksen, Hai Lin, Eric D. Maloney & Courtney Schumacher
 (24 October 2017), "Review of Tropical-Extratropical Teleconnections on Intraseasonal Time Scales", Review of Geophysics, DOI: 10.1002/2016RG000538

http://onlinelibrary.wiley.com/doi/10.1002/2016RG000538/abstract

Abstract: "The interactions and teleconnections between the tropical and midlatitude regions on intraseasonal time scales are an important modulator of tropical and extratropical circulation anomalies and their associated weather patterns. These interactions arise due to the impact of the tropics on the extratropics, the impact of the midlatitudes on the tropics, and two-way interactions between the regions. Observational evidence, as well as theoretical studies with models of complexity ranging from the linear barotropic framework to intricate Earth system models, suggest the involvement of a myriad of processes and mechanisms in generating and maintaining these interconnections. At this stage, our understanding of these teleconnections is primarily a collection of concepts; a comprehensive theoretical framework has yet to be established. These intraseasonal teleconnections are increasingly recognized as an untapped source of potential subseasonal predictability. However, the complexity and diversity of mechanisms associated with these teleconnections, along with the lack of a conceptual framework to relate them, prevent this potential predictability from being translated into realized forecast skill. This review synthesizes our progress in understanding the observed characteristics of intraseasonal tropical-extratropical interactions and their associated mechanisms, identifies the significant gaps in this understanding, and recommends new research endeavors to address the remaining challenges."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on October 27, 2017, 04:57:53 PM
The linked article indicates that in order to more accurately model the Atlantic Meridional Mode, cloud feedback needs to be positive:

Myers, T.A., Mechoso, C.R. & DeFlorio, M.J. (2017), "Importance of positive cloud feedback for tropical Atlantic interhemispheric climate variability", Clim Dy., https://doi.org/10.1007/s00382-017-3978-1

https://link.springer.com/article/10.1007%2Fs00382-017-3978-1?utm_content=buffer90766&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer

Abstract: "Over the tropical Atlantic during boreal spring, average interhemispheric differences in sea-surface temperature (SST) coincide with a coherent pattern of interannual climate variability often referred to as the Atlantic Meridional Mode. This includes anomalous SST and sea-level pressure roughly anti-symmetric about the equator, as well as cross-equatorial near-surface winds directed toward the warmer hemisphere. Within subtropical marine boundary layer cloud regions in both hemispheres, enhanced cloudiness associated with this variability is co-located with cool SST, a strong temperature inversion, and cold horizontal surface temperature advection, while reduced cloudiness is associated with the opposite meteorological conditions. This is indicative a positive cloud feedback that reinforces the underlying SST anomalies. The simulation of this feedback varies widely among models participating in phase 5 of the Coupled Model Intercomparison Project. Models that fail to simulate this feedback substantially underestimate the amplitudes of typical tropical Atlantic interhemispheric variability in cloudiness off of the equator, SST, and atmospheric circulation. Models that correctly reproduce a positive cloud feedback generally produce higher and more realistic amplitudes of variability, but with substantial scatter. Marine boundary layer clouds therefore appear to be a key element of springtime coupled atmosphere–ocean variability over the tropical Atlantic. A markedly more successful simulation of this variability in climate models may be obtained by better representing boundary layer cloud processes."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on October 27, 2017, 05:46:28 PM
If that Bernard paper holds up, it answers the question as to why the polar oceans in Cretaceous and Paleogene were so much warmer. The answer is that they were not, and the equator to pole gradient was larger than supposed.

I think that the key take away message here is that current climate models have likely been calibrated to over predict the amount of heat energy that the oceans will absorb with continuing radiative forcing; which will leave more heat in the atmosphere resulting in more rapid increases in GMSTA (global mean surface temperature anomalies), which implies that ECS is likely towards the upper end of model projections.
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on October 30, 2017, 03:19:01 PM
If you want a model to indicate that you will succeed, all you have to do is to jack around with your assumption/input; and then claim plausible deniability when your projects don't match the future reality. 

Title: "Guest post: Who will deliver the negative emissions needed to avoid 2C warming?"

https://www.carbonbrief.org/guest-post-who-will-deliver-the-negative-emissions-needed-to-avoid-2c-warming

Extract: "“Negative emissions”, also known as “carbon dioxide removal” (CDR), refers to a group of approaches and technologies that take CO2 from the atmosphere and store it on land, underground or in the oceans.

Integrated Assessment Models (IAMs) also indicate that it is cheaper to have large-scale CDR in the future, than to have deeper mitigation now.

Love it or hate it, it may be that CDR is simply unavoidable if society wants to stabilise temperatures. If one can accept that we need CDR, the real debate becomes at what scale.

The land areas required for such large-scale CDR would be the size of India, or even larger."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on October 30, 2017, 07:21:01 PM
The linked open access reference discusses improvements to modeling global soil carbon:

Kefeng Wang, Changhui Peng, Qiuan Zhu, Xiaolu Zhou, Meng Wang, Kerou Zhang & Gangsheng Wang (27 October 2017), "Modeling Global Soil Carbon and Soil Microbial Carbon by Integrating Microbial Processes into the Ecosystem Process Model TRIPLEX-GHG", JAMES, DOI: 10.1002/2017MS000920 

http://onlinelibrary.wiley.com/doi/10.1002/2017MS000920/full

Abstract: "Microbial physiology plays a critical role in the biogeochemical cycles of the Earth system. However, most traditional soil carbon models are lacking in terms of the representation of key microbial processes that control the soil carbon response to global climate change. In this study, the improved process-based model TRIPLEX-GHG was developed by coupling it with the new MEND (Microbial-ENzyme-mediated Decomposition) model to estimate total global soil organic carbon (SOC) and global soil microbial carbon. The new model (TRIPLEX-MICROBE) shows considerable improvement over the previous version (TRIPLEX-GHG) in simulating SOC. We estimated the global soil carbon stock to be approximately 1195 Pg C, with 348 Pg C located in the high northern latitudes, which is in good agreement with the well-regarded Harmonized World Soil Database (HWSD) and the Northern Circumpolar Soil Carbon Database (NCSCD). We also estimated the global soil microbial carbon to be 21 Pg C, similar to the 23 Pg C estimated by Xu et al. (2014). We found that the microbial carbon quantity in the latitudinal direction showed reversions at approximately 30°N, near the equator and at 25°S. A sensitivity analysis suggested that the tundra ecosystem exhibited the highest sensitivity to a 1°C increase or decrease in temperature in terms of dissolved organic carbon (DOC), microbial biomass carbon (MBC), and mineral-associated organic carbon (MOC). However, our work represents the first step toward a new generation of ecosystem process models capable of integrating key microbial processes into soil carbon cycles."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on November 12, 2017, 01:01:03 AM
The linked reference uses a ESM to study the impacts of freshwater hosing from the Greenland Ice Sheet.  While this is valuable information, studying the impacts of abrupt freshwater hosing from the WAIS would be even more useful:

Haijun Yang, Qin Wen, Jie Yao & Yuxing Wang (2017), "Bjerknes Compensation in Meridional Heat Transport under Freshwater Forcing and the Role of Climate Feedback", Journal of Climate, https://doi.org/10.1175/JCLI-D-16-0824.1

http://journals.ametsoc.org/doi/full/10.1175/JCLI-D-16-0824.1

Abstract: "Using a coupled Earth climate model, freshwater forcing experiments are performed to study the Bjerknes compensation (BJC) between meridional atmosphere heat transport (AHT) and meridional ocean heat transport (OHT). Freshwater hosing in the North Atlantic weakens the Atlantic meridional overturning circulation (AMOC) and thus reduces the northward OHT in the Atlantic significantly, leading to a cooling (warming) in the surface layer in the Northern (Southern) Hemisphere. This results in an enhanced Hadley cell and northward AHT. Meanwhile, the OHT in the Indo-Pacific is increased in response to the Hadley cell change, partially offsetting the reduced OHT in the Atlantic. Two compensations occur here: compensation between the AHT and the Atlantic OHT, and that between the Indo-Pacific OHT and the Atlantic OHT. The AHT change undercompensates the OHT change by about 60% in the extratropics, while the former overcompensates the latter by about 30% in the tropics due to the Indo-Pacific change. The BJC can be understood from the viewpoint of large-scale circulation change. However, the intrinsic mechanism of BJC is related to the climate feedback of the Earth system. The authors’ coupled model experiments confirm that the occurrence of BJC is an intrinsic requirement of local energy balance, and local climate feedback determines the extent of BJC, consistent with previous theoretical results. Even during the transient period of climate change, the BJC is well established when the ocean heat storage is slowly varying and its change is much weaker than the net local heat flux change at the ocean surface. The BJC can be deduced from the local climate feedback. Under the freshwater forcing, the overcompensation in the tropics is mainly caused by the positive longwave feedback related to clouds, and the undercompensation in the extratropics is due to the negative longwave feedback related to surface temperature change. Different dominant feedbacks determine different BJC scenarios in different regions, which are in essence constrained by local energy balance."
Title: Re: Modelling the Anthropocene
Post by: Juan C. García on December 07, 2017, 09:03:29 PM
Maybe we should have a topic for evaluating the different climate models. But I don't want to be the person that will open it, because I don't know enough about models.

Anyway, I believe that this news has not been include on this Forum and I find appropiate to included it here.

The most accurate climate change models predict the most alarming consequences, study finds

Washington Post

https://www.washingtonpost.com/news/energy-environment/wp/2017/12/06/the-most-accurate-climate-change-models-predict-the-most-alarming-consequences-study-claims/?wpisrc=nl_green&wpmm=1 (https://www.washingtonpost.com/news/energy-environment/wp/2017/12/06/the-most-accurate-climate-change-models-predict-the-most-alarming-consequences-study-claims/?wpisrc=nl_green&wpmm=1)
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on December 15, 2017, 07:36:57 PM
The linked reference studies the IPO behavior focused on CMIP5 simulations and confirms the importance of correctly modeling the" Tropical-extratropical interactions via both an 'atmospheric bridge' and 'oceanic tunnel' mechanisms:

Benjamin J Henley et al (2017), "Spatial and temporal agreement in climate model
simulations of the Interdecadal Pacific Oscillation", Environ. Res. Lett. 12 044011, https://doi.org/10.1088/1748-9326/aa5cc8

http://iopscience.iop.org/article/10.1088/1748-9326/aa5cc8/pdf

Extract: "Tropical-extratropical interactions via an atmospheric ‘bridge’ (Newman et al 2016) and oceanic ‘tunnel’ (Farneti et al 2014) are likely component mechanisms that contribute to the decadal-scale variability evident in the IPO and PDO indices."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on December 15, 2017, 10:03:39 PM
Maybe we should have a topic for evaluating the different climate models. But I don't want to be the person that will open it, because I don't know enough about models.

Anyway, I believe that this news has not been include on this Forum and I find appropiate to included it here.

The most accurate climate change models predict the most alarming consequences, study finds

Washington Post

https://www.washingtonpost.com/news/energy-environment/wp/2017/12/06/the-most-accurate-climate-change-models-predict-the-most-alarming-consequences-study-claims/?wpisrc=nl_green&wpmm=1 (https://www.washingtonpost.com/news/energy-environment/wp/2017/12/06/the-most-accurate-climate-change-models-predict-the-most-alarming-consequences-study-claims/?wpisrc=nl_green&wpmm=1)

Juan,

I don't want to open a separate folder to compare different climate model projections (as it would be too difficult), but I concur that higher performance models project higher values of climate sensitivity as indicated by the following reposted information and images:

The first linked reference cites findings from an improved version of CESM that increases ESS from 4.1C to 5.6C.  If this is actually experienced this coming century, this is bad news for both people & the current biota:

William R. Frey & Jennifer E. Kay (2017), "The influence of extratropical cloud phase and amount feedbacks on climate sensitivity", Climate Dynamics; pp 1–20, doi:10.1007/s00382-017-3796-5

https://link.springer.com/article/10.1007%2Fs00382-017-3796-5?utm_content=bufferfdbc0&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer

Abstract: "Global coupled climate models have large long-standing cloud and radiation biases, calling into question their ability to simulate climate and climate change. This study assesses the impact of reducing shortwave radiation biases on climate sensitivity within the Community Earth System Model (CESM). The model is modified by increasing supercooled cloud liquid to better match absorbed shortwave radiation observations over the Southern Ocean while tuning to reduce a compensating tropical shortwave bias. With a thermodynamic mixed-layer ocean, equilibrium warming in response to doubled CO2 increases from 4.1 K in the control to 5.6 K in the modified model. This 1.5 K increase in equilibrium climate sensitivity is caused by changes in two extratropical shortwave cloud feedbacks. First, reduced conversion of cloud ice to liquid at high southern latitudes decreases the magnitude of a negative cloud phase feedback. Second, warming is amplified in the mid-latitudes by a larger positive shortwave cloud feedback. The positive cloud feedback, usually associated with the subtropics, arises when sea surface warming increases the moisture gradient between the boundary layer and free troposphere. The increased moisture gradient enhances the effectiveness of mixing to dry the boundary layer, which decreases cloud amount and optical depth. When a full-depth ocean with dynamics and thermodynamics is included, ocean heat uptake preferentially cools the mid-latitude Southern Ocean, partially inhibiting the positive cloud feedback and slowing warming. Overall, the results highlight strong connections between Southern Ocean mixed-phase cloud partitioning, cloud feedbacks, and ocean heat uptake in a climate forced by greenhouse gas changes."

&

The second linked reference provides satellite evidence that the CMIP5 projections substantially underestimate the positive feedback from precipitating clouds.  This is more evidence that consensus science has underestimated climate sensitivity:

J.-L. F. Li, Wei-Liang Lee, Yi-Hui Wang, Mark Richardson, Jia-Yuh Yu, E. Suhas, Eric Fetzer, Min-Hui Lo & Qing Yue (2016), "Assessing the Radiative Impacts of Precipitating Clouds on Winter Surface Air Temperatures and Land Surface Properties in GCMs Using Observations", JGR: Atmospheres, DOI: 10.1002/2016JD025175


http://onlinelibrary.wiley.com/doi/10.1002/2016JD025175/abstract


Abstract: "Using CloudSat-CALIPSO ice water, cloud fraction and radiation; CERES radiation and long-term station-measured surface air temperature (SAT), we identified a substantial underestimation of the total ice water path, total cloud fraction, land surface radiative flux, land surface temperature (LST) and SAT during Northern Hemisphere winter in CMIP5 models. We perform sensitivity experiments with the NCAR Community Earth System Model version 1 (CESM1) in fully coupled modes to identify processes driving these biases. We found that biases in land surface properties are associated with the exclusion of downwelling long-wave heating from precipitating ice during Northern Hemisphere winter. The land surface temperature biases introduced by the exclusion of precipitating ice radiative effects in CESM1 and CMIP5 both spatially correlate with winter biases over Eurasia and North America. The underestimated precipitating ice radiative effect leads to colder LST, associated surface energy-budget adjustments and cooler SAT. This bias also shifts regional soil moisture state from liquid to frozen, increases snow cover and depresses evapotranspiration (ET) and total leaf area index (TLAI) in Northern Hemisphere winter. The inclusion of the precipitating ice radiative effects largely reduces the model biases of surface radiative fluxes (more than 15 W m-2), SAT (up to 2-4 K), snow cover and ET (25-30%), compared with those without snow-radiative effects."

&

The third linked (open access) reference provides a comparison of the best 2014 version of Community Earth Systems Model run to date (CESM-H), and a standard ESM run (CESM-S) such as that used for AR5.  The article, the attached image (and caption) and extracts, make it very clear that while the CESM-H run is not perfect (i.e. there is still a reason to run ACME/E3SM), it is a substantial improvement about the AR5 generation of climate models, and it projects higher increases in mean global temperature increases, and less sea ice (see the figure 1) than the AR5 generation of projections.

R. Justin Small, Julio Bacmeister, David Bailey, Allison Baker, Stuart Bishop, Frank Bryan, Julie Caron, John Dennis, Peter Gent, Hsiao-ming Hsu, Markus Jochum, David Lawrence, Ernesto Muñoz, Pedro diNezio, Tim Scheitlin, Robert Tomas, Joseph Tribbia, Yu-heng Tseng, & Mariana Vertenstein, (December 2014), "A new synoptic scale resolving global climate simulation using the Community Earth System Model", JAMES, Volume 6, Issue 4, Pages 1065–1094, DOI: 10.1002/2014MS000363

http://onlinelibrary.wiley.com/enhanced/doi/10.1002/2014MS000363/

Abstract: "High-resolution global climate modeling holds the promise of capturing planetary-scale climate modes and small-scale (regional and sometimes extreme) features simultaneously, including their mutual interaction. This paper discusses a new state-of-the-art high-resolution Community Earth System Model (CESM) simulation that was performed with these goals in mind. The atmospheric component was at 0.25° grid spacing, and ocean component at 0.1°. One hundred years of “present-day” simulation were completed. Major results were that annual mean sea surface temperature (SST) in the equatorial Pacific and El-Niño Southern Oscillation variability were well simulated compared to standard resolution models. Tropical and southern Atlantic SST also had much reduced bias compared to previous versions of the model. In addition, the high resolution of the model enabled small-scale features of the climate system to be represented, such as air-sea interaction over ocean frontal zones, mesoscale systems generated by the Rockies, and Tropical Cyclones. Associated single component runs and standard resolution coupled runs are used to help attribute the strengths and weaknesses of the fully coupled run. The high-resolution run employed 23,404 cores, costing 250 thousand processor-hours per simulated year and made about two simulated years per day on the NCAR-Wyoming supercomputer “Yellowstone.”"


Extracts: "The high-resolution CESM was run under “present-day” (year 2000) greenhouse gas conditions (fixed CO2 concentration of 367 ppm). This was chosen so that direct comparisons could be made with recent-era observations of fine-scale and large-scale phenomena. The prognostic carbon-nitrogen cycle was not used in this simulation.

In the following, this simulation will be referred to as CESM-High Resolution (CESM-H).

The interpretation of the model data employed in this paper is that the CESM-H and CESM-S are the best simulations available at their respective resolutions, for the same model version, and for year 2000 conditions."


Caption for the first image: "Time series of globally averaged quantities for 100 years of CESM-H (thick black line) and 166 years of CESM-S (thin gray line). (a) Top of atmosphere net radiation, positive incoming to Earth. Data are 10 year running mean. (b) Surface (including ocean, land, ice) temperature, 10 year running average. Sea ice area in (c) Northern Hemisphere and (d) Southern Hemisphere. (e) Atlantic Meridional Overturning Circulation (AMOC), 12 month running averages, (f) transport through Drake Passage due to Antarctic Circumpolar Current (ACC), annual values."

The following link provides public access to various model run outputs:

http://www.earthsystemgrid.org/

Also, Proistosescu & Huybers (2017) show that HadGEM2-ES indicate a range of ECS of from 6 to 8C (see the third & fourth images)

Cristian Proistosescu and Peter J. Huybers (05 Jul 2017), "Slow climate mode reconciles historical and model-based estimates of climate sensitivity", Science Advances, Vol. 3, no. 7, e1602821, DOI: 10.1126/sciadv.1602821

http://advances.sciencemag.org/content/3/7/e1602821

For other efforts to improve the state-of-the-art in ESM projections see also:

https://www.wcrp-climate.org/wgcm-overview
&
https://www.wcrp-climate.org/wgcm-cmip/wgcm-cmip6
&
https://eos.org/project-updates/a-more-powerful-reality-test-for-climate-models

Caption for fourth image: "Fig. 1. The Coupled Model Intercomparison Project Phase 5 (CMIP5) facilitates the comparison of results from various climate models. Shown here are relative error measures of different developmental tests of the National Oceanic and Atmospheric Administration’s Geophysical Fluid Dynamics Laboratory (GFDL) model. Results are based on the global seasonal cycle climatology (1980–2005) computed from Atmospheric Model Intercomparison Project (AMIP) experiments. Rows and columns represent individual variables and models, respectively. The error measure is a spatial root-mean-square error (RMSE) that treats each variable separately. The color scale portrays this RMSE as a relative error by normalizing the result by the median error of all model results [Gleckler et al., 2008]. For example, a value of 0.20 indicates that a model’s RMSE is 20% larger than the median error for that variable across all simulations on the figure, whereas a value of –0.20 means the error is 20% smaller than the median error. The four triangles in grid square show the relative error with respect to the four seasons (in clockwise order, with December–January–February (DJF) at the top; MAM = March–April–May, JJA = June–July–August, and SON = September–October–November). The reference data sets are the default satellite and reanalysis data sets identified by Flato et al. [2013]. TOA = top of atmosphere, SW = shortwave, LW = longwave. Credit: Erik Mason/"
&
And for information on HadGEM3-GC3.1 see:

Title: "HadGEM3-GC3.1: The physical coupled model core of UKESM1 now frozen"

http://www.jwcrp.org.uk/documents/ukesm-jan17hadgem3.pdf
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on December 15, 2017, 11:19:01 PM
The linked AGU session entitled: "A32B: Climate Sensitivity and Feedbacks: Advances and New Paradigms I", indicates that values of ECS are increasing with global warming, and that it is unclear just how high the effective ECS will be by 2100:

https://agu.confex.com/agu/fm17/meetingapp.cgi/Session/31025

See also the following associated article:

Title: "More about Equilibrium Climate Sensitivity"

https://andthentheresphysics.wordpress.com/2017/12/14/more-about-equilibrium-climate-sensitivity/

Extract: "… Kate Marvel says in her summary it’s essentially that

You might think we could estimate this from observations: we’ve emitted carbon dioxide, and the temperature has risen. But the future may differ from the past, and there’s reason to think that the warming we’ve experienced so far is different from the warming to come."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on December 21, 2017, 04:42:16 PM
The linked reference indicates that changing patterns of moisture transport for precipitation in the Arctic is more complex than most climate models currently indicate:

Gimeno-Sotelo, L., Nieto, R., Vázquez, M., and Gimeno, L.: The perfect pattern of moisture transport for precipitation for Arctic sea ice melting, Earth Syst. Dynam. Discuss., https://doi.org/10.5194/esd-2017-122, in review, 2017.

https://www.earth-syst-dynam-discuss.net/esd-2017-122/
&
https://www.earth-syst-dynam-discuss.net/esd-2017-122/esd-2017-122.pdf

Abstract. We have identified the patterns of moisture transport for precipitation over the Arctic region, the Arctic Ocean, and its 13 main subdomains, which better fit with sea ice decline. For this purpose, we studied the different patterns of moisture transport for the case of high/low Arctic sea ice (ASI) extension linked to periods before/after the main change point (CP) in the extension of sea ice. The pattern consists of a general decrease in moisture transport in summer and enhanced moisture transport in autumn and early winter, with different contributions depending on the moisture source and ocean subregion. The pattern is not only statistically significant but also consistent with Eulerian fluxes diagnosis, changes in the frequency of circulation types, and known mechanisms of the effects of snowfall or rainfall on ice in the Arctic. The results of this paper also reveal that the assumed and partially documented enhanced poleward moisture transport from lower latitudes as a consequence of increased moisture from climate change seems to be less simple and constant than typically recognized in relation to enhanced Arctic precipitation throughout the year in the present climate.
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on December 28, 2017, 05:35:05 PM
The linked reference relates the emergent behavior of Arctic precipitation with Arctic Amplification, AA.  When AA increases sufficiently, I am concerned about the impact of future rainfall on numerous positive feedback mechanisms in the Arctic region:

Bruce T. Anderson et al. (27 December 2017), "Emergent behavior of Arctic precipitation in response to enhanced Arctic warming", Journal of Geophysical Research Atmospheres, DOI: 10.1002/2017JD026799

http://onlinelibrary.wiley.com/doi/10.1002/2017JD026799/abstract?utm_content=bufferbe025&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer

Abstract: "Amplified warming of the high latitudes in response to human-induced emissions of greenhouse gases has already been observed in the historical record and is a robust feature evident across a hierarchy of model systems, including the models of the Coupled Model Intercomparison Project Phase 5 (CMIP5). The main aims of this analysis are to quantify inter-model differences in the Arctic amplification (AA) of the global warming signal in CMIP5 RCP8.5 simulations and to diagnose these differences in the context of the energy and water cycles of the region. This diagnosis reveals an emergent behavior between the energetic and hydrometeorological responses of the Arctic to warming: in particular, enhanced AA and its associated reduction in dry static energy convergence is balanced to first order by latent heating via enhanced precipitation. This balance necessitates increasing Arctic precipitation with increasing AA while at the same time constraining the magnitude of that precipitation increase. The sensitivity of the increase, ~1.25 (W/m2)/K [~240 (km3/yr)/K], is evident across a broad range of historical and projected AA values. Accounting for the energetic constraint on Arctic precipitation, as a function of AA, in turn informs understanding of both the sign and magnitude of hydrologic cycle changes that the Arctic may experience."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on December 28, 2017, 06:11:18 PM
The subject matter of the linked reference highlights the importance of correctly modeling the interplay between different ocean basins via the atmosphere:

Wei Zhang et al (27 December 2017), "Dominant Role of Atlantic Multi-decadal Oscillation in the Recent Decadal Changes in Western North Pacific Tropical Cyclone Activity", GRL, DOI: 10.1002/2017GL076397

http://onlinelibrary.wiley.com/doi/10.1002/2017GL076397/abstract?utm_content=bufferd676e&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer

Abstract: "Over the 1997-2014 period, the mean frequency of western North Pacific (WNP) tropical cyclones (TCs) was markedly lower (~18%) than the period 1980-1996. Here we show that these changes were driven by an intensification of the vertical wind shear in the southeastern/eastern WNP tied to the changes in the Walker circulation, which arose primarily in response to the enhanced sea surface temperature (SST) warming in the North Atlantic, while the SST anomalies associated with the negative phase of the Pacific Decadal Oscillation (PDO) in the tropical Pacific and the anthropogenic forcing play only secondary roles. These results are based on observations and experiments using the Geophysical Fluid Dynamics Laboratory (GFDL) Forecast-oriented Low-ocean Resolution Coupled Climate Model (FLOR) coupled climate model. The present study suggests a crucial role of the North Atlantic SST in causing decadal changes to WNP TC frequency."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on January 08, 2018, 07:08:09 PM
The linked reference provides information on land use scenarios for use with the Shared Socioeconomic Pathways, SSP, framework:

Stefan van der Esch, et al (2017), "Exploring future changes in land use and land condition and the impacts on food, water, climate change and biodiversity - Scenarios for the UNCCD Global Land Outlook"

PBL Netherlands Environmental Assessment Agency
The Hague, 2017
PBL publication number: 2076


http://www.pbl.nl/sites/default/files/cms/publicaties/pbl-2017-exploring-future-changes-in-land-use-and-land-condition-2076.pdf
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on January 13, 2018, 07:12:08 PM
Maybe climate models can be upgraded to better account for the impacts of human behavior/values on Earth Systems:

Gerten, D., Schönfeld, M., and Schauberger, B.: On deeper human dimensions in Earth system analysis and modelling, Earth Syst. Dynam. Discuss., https://doi.org/10.5194/esd-2017-125, in review, 2018.

https://www.earth-syst-dynam-discuss.net/esd-2017-125/

Abstract. While humanity is altering planet Earth at unprecedented magnitude and speed, representation of the cultural driving factors and their dynamics in models of the Earth system is limited. In this review and perspectives paper, we argue that more or less distinct environmental value sets can be assigned to religion – a deeply embedded feature of human cultures, here defined as collectively shared belief in something sacred. This assertion renders religious theories, practices and actors suitable for studying cultural facets of anthropogenic Earth system change, especially regarding deeper, non-materialistic motivations that ask about humans' self-understanding in the Anthropocene epoch. We sketch a modelling landscape and outline some research primers, encompassing the following elements: (i) extensions of existing Earth system models by quantitative relationships between religious practices and biophysical processes, building on databases that allow for (mathematical) formalisation of such knowledge, (ii) design of new model types that specifically represent religious morals, actors and activities as part of coevolutionary human-environment dynamics, and (iii) identification of research questions of humanitarian relevance that are underrepresented in purely economic-technocratic modelling and scenario paradigms. While this analysis is by necessity heuristic and semi-cohesive, we hope that it will act as a stimulus for further, interdisciplinary and systematic research on the immaterial dimension of humanity's imprint on the Earth system, both qualitatively and quantitatively.
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on January 16, 2018, 01:27:26 AM
The linked article is '… the first article of a week-long series focused on climate modelling'.  It provides a very nice summary of the consensus science interpretation of climate models and their limitations.  Understanding such modeling fundamentals is essential before critiquing potential surprises (such as ice-climate feedback) that are not adequately addressed by consensus science:

Title: "Q&A: How do climate models work?"

https://www.carbonbrief.org/qa-how-do-climate-models-work

Extract: "In the first article of a week-long series focused on climate modelling, Carbon Brief explains in detail how scientists use computers to understand our changing climate…"
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on January 16, 2018, 01:57:54 AM
I think that the findings of the linked reference '… call for a deep reassessment of the way teleconnections are interpreted, and for a more rigorous way to evaluate causality and dependences between the different components of the climate system', because the current consensus science interpretation of these teleconnections is inadequate:

Vannitsem, S. and Ekelmans, P.: Causal dependences between the coupled ocean-atmosphere dynamics over the Tropical Pacific, the North Pacific and the North Atlantic, Earth Syst. Dynam. Discuss., https://doi.org/10.5194/esd-2018-3, in review, 2018.

https://www.earth-syst-dynam-discuss.net/esd-2018-3/

Abstract. The causal dependences between the dynamics of three different coupled ocean-atmosphere basins, The North Atlantic, the North Pacific and the Tropical Pacific region, NINO3.4, have been explored using data from three reanalyses datasets, namely the ORA-20C, the ORAS4 and the ERA-20C. The approach is based on the Convergent Cross Mapping (CCM) developed by Sugihara et al. (2012) that allows for evaluating the dependences between observables beyond the classical teleconnection patterns based on correlations.

The use of CCM on these data mostly reveals that (i) the Tropical Pacific (NINO3.4 region) only influences the dynamics of the North Atlantic region through its annual climatological cycle; (ii) the atmosphere over the North Pacific is dynamically forcing the North Atlantic on a monthly basis; (iii) on longer time scales (interannual), the dynamics of the North Pacific and the North Atlantic are influencing each other through the ocean dynamics, suggesting a connection through the thermohaline circulation.

These findings shed a new light on the coupling between these three different important regions of the globe. In particular they call for a deep reassessment of the way teleconnections are interpreted, and for a more rigorous way to evaluate causality and dependences between the different components of the climate system.
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on January 16, 2018, 08:58:45 PM
Here is a link to the second article in the series on climate modeling:

Title: "Timeline: The history of climate modeling"

https://www.carbonbrief.org/timeline-history-climate-modelling

Extract: "The climate models used by scientists today rely on some of the world’s most advanced supercomputers. It can take dozens of highly skilled people to build and then operate a modern-day climate model."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on January 16, 2018, 09:48:50 PM
Here is a link to a report on an Earth modeling framework:

Donges, J. F., Heitzig, J., Barfuss, W., Kassel, J. A., Kittel, T., Kolb, J. J., Kolster, T., Müller-Hansen, F., Otto, I. M., Wiedermann, M., Zimmerer, K. B., and Lucht, W.: Earth system modelling with complex dynamic human societies: the copan:CORE World-Earth modeling framework, Earth Syst. Dynam. Discuss., https://doi.org/10.5194/esd-2017-126, in review, 2018.

https://www.earth-syst-dynam-discuss.net/esd-2017-126/

Abstract. Possible future trajectories of the Earth system in the Anthropocene are determined by the increasing entanglement of processes operating in the physical, chemical and biological systems of the planet, as well as in human societies, their cultures and economies. Here, we introduce the copan:CORE open source software library that provides a framework for developing, composing and running World-Earth models, i.e., models of social-ecological co-evolution up to planetary scales. It is an object-oriented software package written in Python designed for different user roles. It allows model end users to run parallel simulations with already available and tested models. Furthermore, model composers are enabled to easily implement new models by plugging together a broad range of model components, such as opinion formation on social networks, generic carbon cycle dynamics, or simple vegetation growth. For the sake of a modular structure, each provided component specifies a meaningful yet minimal collection of closely related processes. These processes can be formulated in terms of various process types, such as ordinary differential equations, explicit or implicit functions, as well as steps or events of deterministic or stochastic fashion. In addition to the already included variety of different components in copan:CORE, model developers can extend the framework with additional components that are based on elementary entity types, i.e., grid cells, individuals and social systems, or the fundamental process taxa environment, social metabolism, and culture. To showcase possible usage we present an exemplary World-Earth model that combines a variety of model components and interactions thereof. As the framework allows a simple activation and deactivation of certain components and related processes, users can test for their specific effects on modeling results and evaluate model robustness in a controlled way. Hence, copan:CORE allows developing process-based models of global change and sustainable development in planetary social-ecological systems and thus fosters a better understanding of crucial mechanisms governing the co-evolutionary dynamics between societies and the natural environment. Due to its modular structure, the framework enhances the development and application of stylized models in Earth system science but also climatology, economics, ecology, or sociology, and allows combining them for interdisciplinary studies at the interface between different areas of expertise.
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on January 17, 2018, 04:13:14 PM
The linked article on how to improve climate models is worth reading, but one still needs to read between the lines in order to really appreciate how far current climate models are erring on the side of least drama:

Title: "In-depth: Scientists discuss how to improve climate models"

https://www.carbonbrief.org/in-depth-scientists-discuss-how-to-improve-climate-models

Extract: "Prof Stefan Rahmstorf
Head of Earth systems analysis
Potsdam Institute for Climate Impact Research

I think a key challenge is non-linear effects, or tipping points."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on January 18, 2018, 02:30:07 PM
Here is the fourth article in the series of five article on climate models:

Title: "Guest post: Why clouds hold the key to better climate models"

https://www.carbonbrief.org/guest-post-why-clouds-hold-key-better-climate-models

Extract: "And there are the things we could still do better:

•   Many of the ways cloud at low altitudes form, evolve and dissolve are not clearly understood and models do not appear to represent them very well.
•   The more detailed cloud resolving models need to be run over larger space and longer time domains to fully understand the benefits they bring
•   Ice clouds have been less well studied and considered so far
•   We need to maximise the information we can get from current and future satellite observations."
Title: Re: Modelling the Anthropocene
Post by: AbruptSLR on January 19, 2018, 11:56:54 AM
Here is a link to the 5th article on climate models.  Without considering any ice-climate feedback the CMIP5 models project more rainfall at high latitudes; which should accelerate polar amplification:

Title: "Explainer: What climate models tell us about future rainfall"

https://www.carbonbrief.org/explainer-what-climate-models-tell-us-about-future-rainfall

Extract: "Changes in average precipitation is much more difficult for climate models to predict than temperature. There are many parts of the world where models disagree whether there will be more or less rain and snow in the future. However, there are some regions, particularly the Mediterranean and southern Africa, where nearly all models suggest rainfall will decrease. Similarly, increases in rainfall are expected in high latitude areas, as well as much of South Asia."