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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1250 on: June 18, 2019, 09:28:25 PM »
The linked reference (& associated article) indicates that as the Western Tropical Pacific sea surface temperature increases (say due to GHG emissions, increasingly strong El Nino events and/or ice-climate feedbacks), the associated telecommunication of energy from the Tropical Pacific will likely service to accelerate the destabilization of the WAIS:

Kyle R. Clem, Benjamin R. Lintner, Anthony J. Broccoli, James R. Miller. Role of the South Pacific Convergence Zone in West Antarctic Decadal Climate Variability. Geophysical Research Letters, 2019; DOI: 10.1029/2019GL082108

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019GL082108

Abstract
Regional atmospheric circulation along coastal West Antarctica associated with the Amundsen Sea Low (ASL) mediates ice shelf melt that governs Antarctica's contribution to global sea level rise. In this study, the South Pacific Convergence Zone (SPCZ) is identified as a significant driver of ASL variability on decadal time scales. Using the Community Earth System Model, we impose a positive sea surface temperature anomaly in the SPCZ that reproduces an increase in convective rainfall in the southwest SPCZ that has been observed in recent decades, consistent with the Interdecadal Pacific Oscillation (IPO). Many of the major observed climate shifts across West Antarctica during the 2000‐2014 period when the IPO was in its negative phase can be explained via a teleconnection over the ASL emanating from the SPCZ. Knowledge of these relationships significantly enhances our understanding and interpretation of past and future West Antarctic climate variability.

Plain Language Summary
Deep convective rainfall in the South Pacific Convergence Zone (SPCZ) alters the regional atmospheric circulation along coastal West Antarctica impacting the regional climate and potentially driving warm ocean water upwelling that melts ice shelves. Increases in SPCZ rainfall cause cooling on the Antarctic Peninsula and warming across the Ross Ice Shelf and portions of East Antarctica. Such conditions were observed during the 2000‐2014 period in which the phase of the Interdecadal Pacific Oscillation (IPO), a naturally‐occurring mode of tropical Pacific decadal variability, was negative. The influence of the SPCZ on West Antarctic climate is consistent with observed shifts in West Antarctic climate over the period 2000‐2014. Therefore, the SPCZ, though a tropical climate feature, is found to be an important driver of West Antarctic climate on decadal time scales governed by the IPO.

See also:

Title: "Warming waters in western tropical Pacific may affect West Antarctic Ice Sheet"

https://www.sciencedaily.com/releases/2019/06/190613095204.htm

Extract: "Warming waters in the western tropical Pacific Ocean have significantly increased thunderstorms and rainfall, which may affect the stability of the West Antarctic Ice Sheet and global sea-level rise, according to a Rutgers University-New Brunswick study."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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Tor Bejnar

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1251 on: June 18, 2019, 09:29:01 PM »
A 2016 paper (Rising atmospheric methane: 2007–2014 growth and isotopic shift   -   summarizedhere) indicated the 2014 'large' increase in atmospheric methane appeared to be largely from tropical wetlands.  I couldn't find a more recent study of methane fingerprinting.
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1252 on: June 18, 2019, 09:39:33 PM »
Per the linked reference many permafrost zones of the Canadian High Arctic are already experiencing thermokarst development.  This is not good news w.r.t. to the positive feedback mechanism associated with permafrost degradation.

Louise M. Farquharson et al. (10 June 2019), "Climate change drives widespread and rapid thermokarst development in very cold permafrost in the Canadian High Arctic", Geophysical Research Letters, https://doi.org/10.1029/2019GL082187

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019GL082187?af=R

Abstract
Climate warming in regions of ice‐rich permafrost can result in widespread thermokarst development, which reconfigures the landscape and damages infrastructure. We present multi‐site time‐series observations which couple ground temperature measurements with thermokarst development in a region of very cold permafrost. In the Canadian High Arctic between 2003 and 2016, a series of anomalously warm summers caused mean thawing indices to be 150 – 240 % above the 1979‐2000 normal resulting in up to 90 cm of subsidence over the 12‐year observation period. Our data illustrate that despite low mean annual ground temperatures, very cold permafrost (<‐10°C) with massive ground ice close to the surface is highly vulnerable to rapid permafrost degradation and thermokarst development. We suggest that this is due to little thermal buffering from soil organic layers and near surface vegetation, and the presence of near surface ground ice. Observed maximum thaw depths at our sites are already exceeding those projected to occur by 2090 under RCP 4.5.

Key Points
•   Observed thermokarst development in very cold permafrost at 3 monitoring sites along a 700 km transect in the Canadian High Arctic.
•   Rapid landscape response to above average summer warmth is due to limited thermal buffering from overlying ecosystem components and near‐surface ground ice.
•   Change was greatest at Mould Bay where thawing index values were 240 % above historic normals causing ~90 cm of subsidence in 12 years.
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1253 on: June 18, 2019, 09:53:48 PM »
As Antarctic Bottom Water (AABW) formation is a major driver of the meridional overturning current; the finding of the linked reference (which in my opinion errs on the side of least drama) that projected Antarctic ice mass loss (following either RCP 4.5 or RCP 8.5) will result in '… a near complete shutdown of AABW formation within just 50 years …', is a positive ice-climate feedback mechanism that is omitted from almost all current consensus climate model projections.

Véronique Lago, and Matthew H. England (2019), "Projected slowdown of Antarctic Bottom Water formation in response to amplified meltwater contributions", Journal of Climate, https://doi.org/10.1175/JCLI-D-18-0622.1

https://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-18-0622.1?af=R

Abstract: "The sinking and recirculation of Antarctic Bottom Water (AABW) is a major regulator of the storage of heat, carbon and nutrients in the ocean. This sinking is sensitive to changes in surface buoyancy, particularly due to freshening as salinity plays a greater role in determining density at cold temperatures. Acceleration in Antarctic ice-shelf and land-ice melt could thus significantly impact the ventilation of the world’s oceans, yet future projections do not usually include this effect in models. Here we use an ocean-sea-ice model to investigate the potential long-term impact of Antarctic meltwater on ocean circulation and heat storage. The freshwater forcing is derived from present-day estimates of meltwater input from drifting icebergs and basal melt, combined with RCP2.6, RCP4.5 and RCP8.5 scenarios of projected amplification of Antarctic meltwater. We find that the additional freshwater induces a substantial slowdown in the formation rate of AABW, reducing ventilation of the abyssal ocean. Under both the RCP4.5 and RCP8.5 meltwater scenarios, there is a near complete shutdown of AABW formation within just 50 years, something not captured by climate model projections. The abyssal overturning at ∼30oS also weakens, with a ∼20 year delay relative to the onset of AABW slowdown. After 200 years, up to ∼50% of the original volume of AABW has disappeared due to abyssal warming, induced by vertical mixing in the absence of AABW ventilation. This suggests that climate change could induce the disappearance of present day abyssal water-masses, with implications for the global distribution of heat, carbon and nutrients."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1254 on: June 19, 2019, 04:57:15 PM »
The linked reference indicates that using current climate models '… the sum of the individual ice volume changes amounts to less than half of the full ice volume response, indicating the existence of strong nonlinearities and forcing synergy."  Also: 'Our results highlight the importance of accurately representing the relative timing of forcings of past ice sheet simulations, and underscore the need for developing coupled climate-ice sheet modeling frameworks that properly capture key feedbacks.'

Hopefully, E3SM can be upgraded sufficiently to hindcaste paleo-events such as the Quaternary.

Tigchelaar, M., Timmermann, A., Friedrich, T., Heinemann, M., and Pollard, D.: Nonlinear response of the Antarctic ice sheet to Quaternary sea level and climate forcing, The Cryosphere Discuss., https://doi.org/10.5194/tc-2019-83, in review, 2019.

https://www.the-cryosphere-discuss.net/tc-2019-83/
https://www.the-cryosphere-discuss.net/tc-2019-83/tc-2019-83.pdf

Abstract. Antarctic ice volume has varied substantially during the Quaternary, with reconstructions suggesting a glacial ice sheet extending to the continental shelf break, and interglacial sea level highstands of several meters. Throughout this period, changes in the Antarctic ice sheet were driven by changes in atmospheric and oceanic conditions and global sea level, yet so far, modeling studies have not addressed which of these environmental forcings dominate, and how they interact in the dynamical ice sheet response. Here we force an Antarctic ice sheet model with global sea level reconstructions and transient, spatially explicit boundary conditions from a 408 ka climate model simulation, not only in concert with each other but, for the first time, also separately. We find that together, these forcings drive glacial-interglacial ice volume changes of 12–14 m SLE, in line with reconstructions and previous modeling studies. None of the individual drivers – atmospheric temperature and precipitation, ocean temperatures, sea level – single-handedly explains the full ice sheet response. In fact, the sum of the individual ice volume changes amounts to less than half of the full ice volume response, indicating the existence of strong nonlinearities and forcing synergy. Both sea level and atmospheric forcing are necessary to create full glacial ice sheet growth, whereas the contribution of ocean melt changes is found to be more a function of ice sheet geometry than climatic change. Our results highlight the importance of accurately representing the relative timing of forcings of past ice sheet simulations, and underscore the need for developing coupled climate-ice sheet modeling frameworks that properly capture key feedbacks.

Edit: Until we have well calibrated models that indicate otherwise, the risk of abrupt loss of ice mass from Antarctica in the coming decades remains a real risk.
« Last Edit: June 19, 2019, 05:09:28 PM by AbruptSLR »
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1255 on: June 19, 2019, 05:23:54 PM »

I'll just infer that Thwaites is one of the prime spots where we'll see MICI proved or disproved in the intermediate future.


While Thwaites is the most important marine glacier to watch, it is physically connected to the Pine Island Glacier; therefore, in the attached image I have sketched a blue line where I speculate that a calving fault will form in the Southwest corner of the Pine Island Ice Shelf. PIIS, sometime in the second half of July 2019.  While I may be wrong, it is at least worth watching, and I note that no consensus climate ice sheet model that I have seen projects such a rapid retreat of the PIIS.

Edit: This image was taken on May 22, 2019

I attach a Sentinel 1 image of the Southwest corner of the PIIS and the ice face of the SW Tributary ice shelf taken on June 19, 2019.  This image shows a minor calving event (which occurred on June 17, 2019) in this corner.  In my opinion one more such event in this Southwest corner of the PIIS should like trigger a major calving event for the PIIS sometime in the second half of July 2019.

Edit: And again I reiterate that no consensus climate ice sheet model that I have seen projects such a rapid retreat of the PIIS ice face.
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1257 on: June 19, 2019, 11:37:50 PM »
The linked reference discusses the impact that microorganisms may have on climate change on human wellbeing, and warns that consensus climate science model projections should more fully consider the interactions between microorganisms and climate change:

Ricardo Cavicchioli et al. (2019), "Scientists’ warning to humanity: microorganisms and climate change", Nature Reviews Microbiology, DOI: https://doi.org/10.1038/s41579-019-0222-5

https://www.nature.com/articles/s41579-019-0222-5

Abstract: "In the Anthropocene, in which we now live, climate change is impacting most life on Earth. Microorganisms support the existence of all higher trophic life forms. To understand how humans and other life forms on Earth (including those we are yet to discover) can withstand anthropogenic climate change, it is vital to incorporate knowledge of the microbial ‘unseen majority’. We must learn not just how microorganisms affect climate change (including production and consumption of greenhouse gases) but also how they will be affected by climate change and other human activities. This Consensus Statement documents the central role and global importance of microorganisms in climate change biology. It also puts humanity on notice that the impact of climate change will depend heavily on responses of microorganisms, which are essential for achieving an environmentally sustainable future."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

Bruce Steele

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1258 on: June 20, 2019, 05:54:13 PM »
How hazardous algae blooms respond to changing oceans conditions may be illustrative of how microbial life responds. Here is an abstract for a webinar by Dave Hutchns that our ocean acidification group ( C-CAN )is sponsoring .
"How ocean acidification works hand-in-hand with warming and other global change stressors to promote toxic Pseudo-nitzschia harmful algal blooms along the West Coast
 
Toxic harmful algal blooms are an increasing problem globally, and the West Coast of the U.S. is no exception. In particular, massive neurotoxic blooms of the domoic acid-producing diatom Pseudo-nitzschia have recently appeared that are larger, more frequent, longer lasting, and much more toxic than any that have been historically recorded.  In recent years, these blooms have caused extensive damage to our Dungeness crab fishery, and they pose an increasing threat to other shellfish and finfish industries. It has become clear that this unprecedented intensification of toxic domoic acid events is very likely linked to ocean environmental change.  For instance, research in my laboratory has shown that ocean acidification can benefit the growth and increase the toxicity of many harmful algal bloom species, including Pseudo-nitzschia. At present day atmospheric CO2 concentrations, obtaining enough dissolved CO2 from the water to support growth can be a problem for Pseudo-nitzschia, which can thus be “carbon dioxide-limited”, and so it may actually directly benefit from higher CO2 levels. There is a definite potential for future CO2 fertilization of more frequent and more intense toxic algal blooms. However, we are now realizing that to understand and predict how ocean acidification will influence harmful algal blooms, we also need to consider a number of other interacting global change impacts. These other direct and indirect human disturbances include sea surface warming, losses of dissolved oxygen, stratification of the surface ocean, and modification of natural nutrient cycles by urban and agricultural pollution. For instance, in addition to ocean acidification, we have also shown that ocean warming strongly promotes domoic acid production by Pseudo-nitzschia.  I will discuss the complex network of interactions between ocean acidification and these many other global change multiple stressors that my lab group is currently working to understand, in order to help predict and perhaps mitigate the tremendously damaging toxic algal blooms that increasingly threaten our coastal fisheries and marine food webs."
 
« Last Edit: June 20, 2019, 06:00:34 PM by Bruce Steele »

AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1259 on: June 20, 2019, 05:55:54 PM »
The linked article indicates that it may not be easy to correct the damage done to the climate by the Trump Administration's rollback of U.S. regulations on coal:

Title: "How the EPA's climate rule rollback could reach beyond coal"

https://www.axios.com/epa-climate-rule-coal-power-20f3bed0-aa2e-4576-9b22-82cf6ba076af.html

Extract: "A big question now that EPA has finalized climate regulations for power plants is how much they'll constrain a future president — especially a potential Democrat that wants to act way more aggressively.

"EPA's narrow approach to the power sector rulemaking could pose hurdles to future regulation of other sectors under a differently minded future administration," the consultancy ClearView Energy Partners said in a note."
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FrostKing70

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1260 on: June 20, 2019, 06:16:34 PM »
There are ways to make it easier to change in the future.  For example, if Congress were to pass a bill expanding or changing the EPA mandate, then there would be new rules to support the change.

Adam Ash

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1261 on: June 21, 2019, 09:43:36 AM »
Isn't it simpler than that?  Adjusting 'policy' to encourage reluctant energy producers to eventually emit less (i.e. to generate less) will not achieve any meaningful change in the time we have left.

At some point someone is going to have to announce to their adoring public:  "In order to save humanity from itself (and this means 'you'!), on Friday, half of all fossil-fuel-powered electric generation in our country will be permanently shut down.  Unless you are already prepared for this (and I know some folks are) this may result in a substantial disruption to your way of life.  Please make your own arrangements to deal with this situation, noting that you should have made these preparations already.  Thank you and good night."
Done.  We're screwed if its not.

Lennart van der Linde

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1262 on: June 21, 2019, 12:01:34 PM »
Aschwanden et al 2019 on potential Greenland ice mass loss in the coming centuries:
https://advances.sciencemag.org/content/5/6/eaav9396?fbclid=IwAR2B6SbuwJ8009PDv7YFpEeoK4xv076tCnloSI_KHIJj6GfMlKcReZEYan4

They estimate about a 16% chance that the GIS will be completely gone in no more than five centuries under RCP8.5, and about a 50% chance that this would take no more than seven centuries (see their fig 1b below).

Laurent

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1263 on: June 23, 2019, 05:52:35 PM »
That site may be useful to have a better idea on how the plates did move since the Pangea (240 million years ago). http://portal.gplates.org/cesium/?view=rift_v&utm_content=bufferb7415&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer I include the sea level over a larger time span from exxon apparently.
« Last Edit: June 23, 2019, 11:44:28 PM by Laurent »

AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1264 on: June 23, 2019, 06:18:58 PM »
As consensus climate scientists typically 'err on the side of least drama' (ESLD), they would undoubtable contribute more to reducing climate risks by applying 'Drama theory' to their own actions as well as that of the general-public, and decision makers, before they make recommendations such as the Carbon Budgets:

Title: "Drama theory"

https://en.wikipedia.org/wiki/Drama_theory

Extract: "Drama-theorists build and analyze models (called card tables or options boards) that are isomorphic to game models, but unlike game theorists and most other model-builders, do not do so with the aim of finding a 'solution'. Instead, the aim is to find the dilemmas facing characters and so help to predict how they will re-define the model itself – i.e., the game that will be played. Such prediction requires not only analysis of the model and its dilemmas, but also exploration of the reality outside the model; without this it is impossible to decide which ways of changing the model in order to eliminate dilemmas might be rationalized by the characters.

The relation between drama theory and game theory is complementary in nature. Game theory does not explain how the game that is played is arrived at – i.e., how players select a small number of players and strategies from the virtually infinite set they could select, and how they arrive at common knowledge about each other's selections and preferences for the resulting combinations of strategies. Drama theory tries to explain this, and also to explain how the 'focal point' is arrived at for the 'game with a focal point' that is finally played. On the other hand, drama theory does not explain how players will act when they finally have to play a particular 'game with a focal point', even though it has to make assumptions about this. This is what game theory tries to explain and predict."
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1265 on: June 24, 2019, 02:29:58 AM »
At least the US House of Representative realizes that we are already in a 'Climate Crisis':

House Select Committee on the Climate Crisis

https://climatecrisis.house.gov/
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1266 on: June 24, 2019, 08:17:29 PM »
While this has been discussed previously, I remind readers that about 17.7 kya Mount Takahe near the Thwaites Gateway erupted and created an Antarctic ozone hole comparable that the one that exists today.  The paleo-event lead to an abrupt acceleration of Southern Hemisphere deglaciation; in a comparable manner as I believe is occurring today:

Joseph R. McConnell et al. (September 19, 2017), "Synchronous volcanic eruptions and abrupt climate change ∼17.7 ka plausibly linked by stratospheric ozone depletion", PNAS 114 (38) 10035-10040; https://doi.org/10.1073/pnas.1705595114

https://www.pnas.org/content/114/38/10035

Significance

Cold and dry glacial-state climate conditions persisted in the Southern Hemisphere until approximately 17.7 ka, when paleoclimate records show a largely unexplained sharp, nearly synchronous acceleration in deglaciation. Detailed measurements in Antarctic ice cores document exactly at that time a unique, ∼192-y series of massive halogen-rich volcanic eruptions geochemically attributed to Mount Takahe in West Antarctica. Rather than a coincidence, we postulate that halogen-catalyzed stratospheric ozone depletion over Antarctica triggered large-scale atmospheric circulation and hydroclimate changes similar to the modern Antarctic ozone hole, explaining the synchronicity and abruptness of accelerated Southern Hemisphere deglaciation.

Abstract

Glacial-state greenhouse gas concentrations and Southern Hemisphere climate conditions persisted until ∼17.7 ka, when a nearly synchronous acceleration in deglaciation was recorded in paleoclimate proxies in large parts of the Southern Hemisphere, with many changes ascribed to a sudden poleward shift in the Southern Hemisphere westerlies and subsequent climate impacts. We used high-resolution chemical measurements in the West Antarctic Ice Sheet Divide, Byrd, and other ice cores to document a unique, ∼192-y series of halogen-rich volcanic eruptions exactly at the start of accelerated deglaciation, with tephra identifying the nearby Mount Takahe volcano as the source. Extensive fallout from these massive eruptions has been found >2,800 km from Mount Takahe. Sulfur isotope anomalies and marked decreases in ice core bromine consistent with increased surface UV radiation indicate that the eruptions led to stratospheric ozone depletion. Rather than a highly improbable coincidence, circulation and climate changes extending from the Antarctic Peninsula to the subtropics—similar to those associated with modern stratospheric ozone depletion over Antarctica—plausibly link the Mount Takahe eruptions to the onset of accelerated Southern Hemisphere deglaciation ∼17.7 ka.
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1267 on: June 25, 2019, 04:25:10 PM »
More green energy measures to fight climate change assume that energy demand will not grow as the price of their energy decreases; however, the Jevons paradox indicates that as the price of energy decreases (due to increased efficiencies) demand will increase.  This means that green energy measures will be less effective than most advocates believe:

Title: "Jevons paradox"

https://en.wikipedia.org/wiki/Jevons_paradox

Extract: "In economics, the Jevons paradox (sometimes Jevons effect) occurs when technological progress or government policy increases the efficiency with which a resource is used (reducing the amount necessary for any one use), but the rate of consumption of that resource rises due to increasing demand. The Jevons paradox is perhaps the most widely known paradox in environmental economics. However, governments and environmentalists generally assume that efficiency gains will lower resource consumption, ignoring the possibility of the paradox arising.
 
In 1865, the English economist William Stanley Jevons observed that technological improvements that increased the efficiency of coal-use led to the increased consumption of coal in a wide range of industries. He argued that, contrary to common intuition, technological progress could not be relied upon to reduce fuel consumption."
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1268 on: June 25, 2019, 05:30:24 PM »
The linked reference discusses efforts to calibrate the Community Earth System Model, CESM, to better project the poleward migration of moisture to Antarctica.  Such work can be used to better project the risk of future rainfall events (at low elevations) in West Antarctica and their potential impact on hydrofracturing risks to destabilize West Antarctic ice shelves:

Adriana Bailey et al. (20 June 2019), "Evaluating a Moist Isentropic Framework for Poleward Moisture Transport: Implications for Water Isotopes over Antarctica", Geophysical Research Letters, https://doi.org/10.1029/2019GL082965

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019GL082965?af=R

Abstract: "The ability to identify moisture source regions and sinks, and to model the transport pathways that link them in simple yet physical ways, is critical for understanding climate today and in the past. Using water tagging and isotopic tracer experiments in the Community Earth System Model, this work shows that poleward moisture transport largely follows surfaces of constant moist entropy. The analysis not only provides insight into why distinct zonal bands supply moisture to high‐ and low‐elevation polar sites but also explains why changes in these source regions are inherently linked to changes in temperature and rainout. Moreover, because the geometry, and specifically length, of the moist isentropic surfaces describes how much integrated rainout occurs, the analysis provides a physical framework for interpreting the isotopic composition of water in poleward‐moving air, thus indicating how variations in moisture transport might influence Antarctic ice cores."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1269 on: June 25, 2019, 05:38:10 PM »
The linked (open access) reference indicates that during the mid-Pliocene wildfires were more common in the Arctic than they are today.  Hopefully, climate models will include this climate risk into their future projections:

Fletcher, T. L., Warden, L., Sinninghe Damsté, J. S., Brown, K. J., Rybczynski, N., Gosse, J. C., and Ballantyne, A. P.: Evidence for fire in the Pliocene Arctic in response to amplified temperature, Clim. Past, 15, 1063-1081, https://doi.org/10.5194/cp-15-1063-2019, 2019.

https://www.clim-past.net/15/1063/2019/

Abstract: "The mid-Pliocene is a valuable time interval for investigating equilibrium climate at current atmospheric CO2 concentrations because atmospheric CO2 concentrations are thought to have been comparable to the current day and yet the climate and distribution of ecosystems were quite different. One intriguing, but not fully understood, feature of the early to mid-Pliocene climate is the amplified Arctic temperature response and its impact on Arctic ecosystems. Only the most recent models appear to correctly estimate the degree of warming in the Pliocene Arctic and validation of the currently proposed feedbacks is limited by scarce terrestrial records of climate and environment. Here we reconstruct the summer temperature and fire regime from a subfossil fen-peat deposit on west–central Ellesmere Island, Canada, that has been chronologically constrained using cosmogenic nuclide burial dating to 3.9+1.5/−0.5 3.9+1.5/-0.5 Ma.

The estimate for average mean summer temperature is 15.4±0.8 ∘C using specific bacterial membrane lipids, i.e., branched glycerol dialkyl glycerol tetraethers. This is above the proposed threshold that predicts a substantial increase in wildfire in the modern high latitudes. Macro-charcoal was present in all samples from this Pliocene section with notably higher charcoal concentration in the upper part of the sequence. This change in charcoal was synchronous with a change in vegetation that included an increase in abundance of fire-promoting Pinus and Picea. Paleo-vegetation reconstructions are consistent with warm summer temperatures, relatively low summer precipitation and an incidence of fire comparable to fire-adapted boreal forests of North America and central Siberia.

To our knowledge, this site provides the northernmost evidence of fire during the Pliocene. It suggests that ecosystem productivity was greater than in the present day, providing fuel for wildfires, and that the climate was conducive to the ignition of fire during this period. The results reveal that interactions between paleo-vegetation and paleoclimate were mediated by fire in the High Arctic during the Pliocene, even though CO2 concentrations were similar to modern values."
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1270 on: June 25, 2019, 05:50:56 PM »
The linked reference provides evidence that it will be difficult to get politically conservative individuals to fully accept climate change risks simply by using logic and data.  This implies that it will be more difficult to get off over our current BAU pathway then many individuals believe:

Matthew S. Nurse & Will Grant (16 Jun 2019), "I’ll See It When I Believe It: Motivated Numeracy in Perceptions of Climate Change Risk", Environmental Communication, https://doi.org/10.1080/17524032.2019.1618364

https://www.tandfonline.com/doi/full/10.1080/17524032.2019.1618364?af=R

Abstract: "People’s attitudes about Anthropogenic Climate Change (ACC) risks are not only influenced by scientific data, such as the likelihood of harm, the consequences of failing to act and the cost and effectiveness of mitigation. Instead, when people receive information about controversial topics of decision-relevant science like ACC they often defer to their political attitudes. Recent research has shown that more numerate people can be more polarized about these topics despite their better ability to interpret the scientific data. In this study, we investigated whether the motivated numeracy effect originally found by Kahan, Peters, Dawson, and Slovic [2017. Motivated numeracy and enlightened self-government. Behavioural Public Policy, 1(1)] on the controversial topic of gun control laws in the United States also applies to people when assessing ACC risks. This randomized controlled experiment (N = 504) of Australian adults extends the motivated reasoning thesis by finding evidence that highly numerate people who receive scientific data about ACC use motivated numeracy to rationalize their interpretations in line with their attitudes."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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b_lumenkraft

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1271 on: June 25, 2019, 06:26:14 PM »
Quote
evidence that it will be difficult to get politically conservative individuals to fully accept climate change risks simply by using logic and dat

No shit, good there is a study i guess.

From 13yo i had evidence for that too: Family gatherings.

AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1272 on: June 25, 2019, 11:05:21 PM »
The linked (open access) reference indicates that the West Greenland ice sheet experienced elevated levels (compared to modern) of precipitation during the Holocene Thermal Maximum.  These findings increase the risks that future increases in rainfall at low elevations in coastal West Greenland may accelerate hydrofracturing of key marine terminating glaciers like at the calving front of Jakobshavn Glacier:

Downs, J., Johnson, J., Briner, J., Young, N., Lesnek, A., and Cuzzone, J.: West Greenland ice sheet retreat history reveals elevated precipitation during the Holocene thermal maximum, The Cryosphere Discuss., https://doi.org/10.5194/tc-2019-129, in review, 2019.

https://www.the-cryosphere-discuss.net/tc-2019-129/

Abstract. We investigate changing precipitation patterns in the Kangerlussuaq region of west central Greenland during the Holocene thermal maximum, using a new chronology of ice sheet terminus position through the Holocene and a novel inverse modeling approach based on the unscented transform (UT). The UT is applied to estimate changes in annual precipitation in order to reduce the misfit between modeled and observed terminus positions. We demonstrate the effectiveness of the UT for time-dependent data assimilation, highlighting its low computational cost and trivial parallel implementation. Our results indicate that Holocene warming coincided with elevated precipitation, without which modeled retreat in the Kangerlussuaq region is more rapid than suggested by observations. Less conclusive is if high temperatures during the HTM were specifically associated with a transient increase in precipitation, as the results depend on the assumed temperature history. The importance of precipitation in controlling ice sheet extent during the Holocene underscores the importance of Arctic sea ice loss and changing precipitation patterns on the future stability of the GrIS.
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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gerontocrat

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1273 on: June 25, 2019, 11:17:23 PM »
The linked (open access) reference indicates that the West Greenland ice sheet experienced elevated levels (compared to modern) of precipitation during the Holocene Thermal Maximum.  These findings increase the risks that future increases in rainfall at low elevations in coastal West Greenland may accelerate hydrofracturing of key marine terminating glaciers like at the calving front of Jakobshavn Glacier:

As seems to be happening right now in West Greenland.

High melt but higher precipitation, especially in West Greenland, which is not usual. Supposed to be the dry month and the West even drier than the East.

Precipitation> melt = Surface Mass balance gain.

Also some will be of rain at low elevations.

And three?  weeks ago the DMI guys were predicting a humdinger of a 2019 melt season. They might be right about the melt but maybe precipitation will lead to a lot of mass gain (at least in the next few days).

Last post was
https://forum.arctic-sea-ice.net/index.php/topic,2543.msg208183.html#msg208183

The shape of things to come. Interesting days ahead.
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1274 on: June 26, 2019, 09:25:03 PM »
The linked reference indicates that for vigorous warming scenarios (like RCP8.5) future socioeconomic energy demands will likely be 25 to 58% higher than previously assumed by the scenarios by 2050, largely due to higher than assumed cooling and heating demands.

Bas J. van Ruijven, Enrica De Cian & Ian Sue Wing (2019), "Amplification of future energy demand growth due to climate change", Nature Communications,  10, Article number: 2762, DOI: https://doi.org/10.1038/s41467-019-10399-3

https://www.nature.com/articles/s41467-019-10399-3

Abstract: "Future energy demand is likely to increase due to climate change, but the magnitude depends on many interacting sources of uncertainty. We combine econometrically estimated responses of energy use to income, hot and cold days with future projections of spatial population and national income under five socioeconomic scenarios and temperature increases around 2050 for two emission scenarios simulated by 21 Earth System Models (ESMs). Here we show that, across 210 realizations of socioeconomic and climate scenarios, vigorous (moderate) warming increases global climate-exposed energy demand before adaptation around 2050 by 25–58% (11–27%), on top of a factor 1.7–2.8 increase above present-day due to socioeconomic developments. We find broad agreement among ESMs that energy demand rises by more than 25% in the tropics and southern regions of the USA, Europe and China. Socioeconomic scenarios vary widely in the number of people in low-income countries exposed to increases in energy demand."
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1275 on: June 26, 2019, 09:37:29 PM »
The linked reference finds that the Amazon rainforest could be devastated by 2050 unless rapid progress is made to zero deforestation:

Vitor H. F. Gomes et al. (2019), "Amazonian tree species threatened by deforestation and climate change", Nature Climate Change,  9, 547–553, DOI: https://doi.org/10.1038/s41558-019-0500-2

https://www.nature.com/articles/s41558-019-0500-2

Abstract: "Deforestation is currently the major threat to Amazonian tree species but climate change may surpass it in just a few decades. Here, we show that climate and deforestation combined could cause a decline of up to 58% in Amazon tree species richness, whilst deforestation alone may cause 19–36% and climate change 31–37% by 2050. Quantification is achieved by overlaying species distribution models for current and future climate change scenarios with historical and projected deforestation. Species may lose an average of 65% of their original environmentally suitable area, and a total of 53% may be threatened according to IUCN Red List criteria; however, Amazonian protected area networks reduce these impacts. The worst-case combined scenario—assuming no substantial climate or deforestation policy progress—suggests that by 2050 the Amazonian lowland rainforest may be cut into two blocks: one continuous block with 53% of the original area and another severely fragmented block. This outlook urges rapid progress to zero deforestation, which would help to mitigate climate change and foster biodiversity conservation."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1276 on: June 27, 2019, 05:43:53 PM »
The linked reference calculates the radiative heating of a sea ice free Arctic Ocean during the sunlit part of the year and assuming constant cloudiness they '… calculate a global radiative heating of 0.71 W/m2 relative to the 1979 baseline state. This is equivalent to …' hastening global warming by an estimated 25 years.  While this may seem like an irrelevant worst-case scenario, it could possible occur sometime after 2050 if the WAIS were to begin an MICI-type of collapse sometime between 2035 & 2040, leading to an abrupt slowdown of the MOC and an associated rapid warming of the Tropical Pacific SST; which could trigger an equable climate in the NH; which could lead to a sea ice free Arctic Ocean during the sunlit part of the year prior to 2075.

Kristina Pistone et al. (20 June 2019), "Radiative Heating of an Ice‐free Arctic Ocean", Geophysical Research Letters, https://doi.org/10.1029/2019GL082914

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019GL082914?af=R

Abstract: "During recent decades, there has been dramatic Arctic sea ice retreat. This has reduced the top‐of‐atmosphere albedo, adding more solar energy to the climate system. There is substantial uncertainty regarding how much ice retreat and associated solar heating will occur in the future. This is relevant to future climate projections, including the timescale for reaching global warming stabilization targets. Here we use satellite observations to estimate the amount of solar energy that would be added in the worst‐case scenario of a complete disappearance of Arctic sea ice throughout the sunlit part of the year. Assuming constant cloudiness, we calculate a global radiative heating of 0.71 W/m2 relative to the 1979 baseline state. This is equivalent to the effect of one trillion tons of CO2 emissions. These results suggest that the additional heating due to complete Arctic sea ice loss would hasten global warming by an estimated 25 years."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1277 on: June 27, 2019, 06:06:43 PM »
The linked article calculates that due to recent more accurate estimates of SSTs that the IPCC SR15's carbon budget to stay below a 1.5C GMSTA will be spent 3 to 5 years sooner that previously assumed by consensus climate scientists.  However, if climate sensitivity is higher than consensus climate scientists assume, then we may already spent all of our carbon budget and then some.

Title: "Analysis: Major update to ocean-heat record could shrink 1.5C carbon budget"

https://www.carbonbrief.org/analysis-major-update-to-ocean-heat-record-could-shrink-1-5c-carbon-budget

Extract: "The UK’s Met Office recently released “HadSST4”, the largest update since 2011 to its widely used sea surface temperature (SST) record.

The new version provides more accurate estimates of SSTs in the period during and after the second world war, as well as over the past decade. It suggests that the world’s oceans have warmed by around 0.1C more than previously thought since pre-industrial times.

Carbon Brief estimates that the revisions to the Hadley SST record would reduce the global “carbon budget” remaining to limit warming to 1.5C by between 24% and 33%, depending on how the budget is calculated.

This means that instead of having 9-13 years of current emissions before 1.5C is exceeded, the budget only has 6-10 years left.

These 1.5C carbon budgets are still subject to wide uncertainties in the sensitivity of the climate to additional CO2 …"
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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Tom_Mazanec

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1278 on: June 27, 2019, 08:49:22 PM »
You know, if we start getting multiple meters per century, that is equivalent to multiple centimeters per year. And several centimeters is from just below my lips to just above my nostrils.

kassy

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1279 on: June 29, 2019, 06:31:38 PM »
the budget only has 6-10 years left.

And the big oil countries are still stalling at ipcc because leaving crap out of reports is going to change their world....the EU can´t lead because some eastern countries still love their coal and the rest of the world wants to sell coal or catch up in living standards using the old fashioned build coal for electricity.

We are soon approaching the can´t kick that can down the road moment....

On a slightly more cheerful note i am going to embroider my urn with this:
due to recent more accurate estimates of SSTs that the IPCC SR15's carbon budget to stay below a 1.5C GMSTA will be spent 3 to 5 years sooner that previously assumed by consensus climate scientists.  However, if climate sensitivity is higher than consensus climate scientists assume, then we may already spent all of our carbon budget and then some.


So thanks!


Þetta minnismerki er til vitnis um að við vitum hvað er að gerast og hvað þarf að gera. Aðeins þú veist hvort við gerðum eitthvað.

AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1280 on: June 30, 2019, 10:01:19 PM »
...

On a slightly more cheerful note i am going to embroider my urn with this:
due to recent more accurate estimates of SSTs that the IPCC SR15's carbon budget to stay below a 1.5C GMSTA will be spent 3 to 5 years sooner that previously assumed by consensus climate scientists.  However, if climate sensitivity is higher than consensus climate scientists assume, then we may have already spent all of our carbon budget and then some.


So thanks!

It is not wise for consensus scientists who calculate Carbon Budgets that underestimate the proven effectiveness of the fossil fuel industry to undermine global climate talks:

Title: "The Fossil Fuel Industry Is Quietly Undermining Global Climate Talks"

https://www.bloomberg.com/news/articles/2019-06-24/the-fossil-fuel-industry-is-quietly-undermining-global-climate-talks

Extract: "Fossil fuel industry giants such as ExxonMobil and Royal Dutch Shell are maintaining an outsized presence at global climate discussions, working to undermine scientific consensus and slow policy progress, according to findings released Wednesday by an environmental monitoring organization.

The Climate Investigations Center (CIC) report claims that fossil fuel trade associations have sent more than 6,400 delegates to climate talks since 1995, including delegates from Shell, BP and ExxonMobil.

“The legacy of fossil fuel corporate impact on the Unfccc process and the IPCC is both invisible and impossible to forget,” said CIC Director Kert Davies in a statement. “Fossil fuel interests have tried from the very beginning to undermine and infiltrate this difficult global agreement to make sure that it failed or faltered at each step. As they win, the planet loses.”"
« Last Edit: July 01, 2019, 04:17:45 PM by AbruptSLR »
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KiwiGriff

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1281 on: July 01, 2019, 11:53:39 AM »
IPCC SR15's carbon budget to stay below a 1.5C :P

Aerosols mostly from burning hydrocarbons result in approximately  0.4C of cooling.
This cooling influence is going to reduce at the same rate as we reduce emissions .
Presently we are above preindustrial by about 1.25C and warming at 0.2C a decade. 

The fact that a budget for staying below 1.5C  is talked about by the IPCC or anyone else supposedly informed by the science does my head in.
The "Budget for 1.5C" was gone at  lest a decade ago.
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1282 on: July 01, 2019, 04:46:16 PM »
IPCC SR15's carbon budget to stay below a 1.5C :P

Aerosols mostly from burning hydrocarbons result in approximately  0.4C of cooling.
This cooling influence is going to reduce at the same rate as we reduce emissions .
Presently we are above preindustrial by about 1.25C and warming at 0.2C a decade. 

The fact that a budget for staying below 1.5C  is talked about by the IPCC or anyone else supposedly informed by the science does my head in.
The "Budget for 1.5C" was gone at  lest a decade ago.

The attached image confirms your thinking, in that measured negative aerosol feedback implies that the brown PDF indicates that Transient Climate Response (TCR) is currently higher than assumed by consensus climate science (shown by the grey PDF).  Furthermore, assuming no significant carbon capture technology is implemented any time soon, then for the mean TCR of the brown PDF, the blue line of 'Centennial committed warming' indicates that we are already committed to a GMSTA of about 1.75K.  However, if one uses a higher confidence level for TCR, and/or if one acknowledges that climate sensitivity (especially ECS) increases with global warming, then we could very well already be committed for GMSTA to exceed 2K.
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1283 on: July 01, 2019, 05:00:05 PM »


However, if one uses a higher confidence level for TCR, and/or if one acknowledges that climate sensitivity (especially ECS) increases with global warming, then we could very well already be committed for GMSTA to exceed 2K.

However, per the linked article, even the most Pollyannaish scenario for energy related CO2 emissions thru 2040 assumes that we will be collectively adding to our GMSTA commitment, even assuming high-levels of implementation of both sustainable energy and negative emissions technology.

Title: "Visualizing the varied world energy projections"

https://www.axios.com/energy-outlooks-climate-change-visualization-bb2efc26-0927-4c70-b09a-34e023567404.html

Extract: "Here are some high-level takeaways from the comparison:
•   The studies agree that absent strong climate efforts, consumption grows "20–30% or more through 2040 and beyond, led largely by fossil fuels," notes RFF president Richard Newell and colleagues Daniel Raimi and Gloria Aldana.
•   That's driven largely in the global "east" — that is, Asia-Pacific, Africa and the Middle East — while consumption in the global "west" is largely flat.
•   Renewables surge, but without more ambition on climate, they "primarily add to, rather than displace, fossil fuels.""
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1284 on: July 01, 2019, 05:14:21 PM »
For those who are not sure what consensus climate science projections of GMSTA for different SSP scenarios are, I provide the attached image by Ed Hawkins (where the vertical scale has greater climate action at the top and lower climate action at the bottom).
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1285 on: July 01, 2019, 05:20:13 PM »
Many Canadian climate scientists are currently looking for employment, and the linked article indicates that many Alaskan climate scientists will soon be joining them, due to state budget cuts:

Title: "Universities Are Economic And Knowledge Engines - A Proposed 41% Cut In Alaska Is Scary"

https://www.forbes.com/sites/marshallshepherd/2019/06/30/universities-are-economic-and-knowledge-engines-a-proposed-41-cut-in-alaska-is-scary/#224bdfc26925
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RoxTheGeologist

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1286 on: July 01, 2019, 08:14:08 PM »
...

On a slightly more cheerful note i am going to embroider my urn with this:
due to recent more accurate estimates of SSTs that the IPCC SR15's carbon budget to stay below a 1.5C GMSTA will be spent 3 to 5 years sooner that previously assumed by consensus climate scientists.  However, if climate sensitivity is higher than consensus climate scientists assume, then we may have already spent all of our carbon budget and then some.


So thanks!

It is not wise for consensus scientists who calculate Carbon Budgets that underestimate the proven effectiveness of the fossil fuel industry to undermine global climate talks:

Title: "The Fossil Fuel Industry Is Quietly Undermining Global Climate Talks"

https://www.bloomberg.com/news/articles/2019-06-24/the-fossil-fuel-industry-is-quietly-undermining-global-climate-talks

Extract: "Fossil fuel industry giants such as ExxonMobil and Royal Dutch Shell are maintaining an outsized presence at global climate discussions, working to undermine scientific consensus and slow policy progress, according to findings released Wednesday by an environmental monitoring organization.

The Climate Investigations Center (CIC) report claims that fossil fuel trade associations have sent more than 6,400 delegates to climate talks since 1995, including delegates from Shell, BP and ExxonMobil.

“The legacy of fossil fuel corporate impact on the Unfccc process and the IPCC is both invisible and impossible to forget,” said CIC Director Kert Davies in a statement. “Fossil fuel interests have tried from the very beginning to undermine and infiltrate this difficult global agreement to make sure that it failed or faltered at each step. As they win, the planet loses.”"

This has been my experience on a tiny scale. I'm part of the trade association for diesel replacement fuels, and we have a huge budget of $140,000 to spend on marketing. In contrast I was at a posh charity even a month or so ago (filled with the great and the good?) and chevron donated $100,000, just like that; And it's a tiny fraction of the money they spend in California on lobbying. They have unlimited resources. They understand the constituency of every Assembly member, and who there main contributors are. They can make or break a members re-election chances, ensuring who gets voted in tows the party line. I have enormous respect for their ability to bend the legislature to their will. Now that they appear to be winning ground with the unions (refinery workers, oil field workers, etc) it's going to be an uphill struggle just to keep our current legislation in place.


AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1287 on: July 02, 2019, 11:01:15 PM »
The linked reference indicates that consensus climate science documents like AR6 would build more support for climate action by emphasizing projections with a 90% confidence level for concrete events like heat waves and flood risks:

Susan Joslyn and Raoni Demnitz (2019), "Communicating Climate Change: Probabilistic Expressions and Concrete Events", Weather, Climate and Society, https://doi.org/10.1175/WCAS-D-18-0126.1

https://journals.ametsoc.org/doi/abs/10.1175/WCAS-D-18-0126.1?af=R

Abstract
Despite near unanimous agreement among climate scientists about global warming, a substantial proportion of Americans remain skeptical or unconcerned. The two experiments reported here, tested communication strategies designed to increase trust in, and concern about climate change. They also measured attitudes toward climate scientists. Climate predictions were systematically manipulated to include either probabilistic (90% predictive interval) or deterministic (mean value) projections that described either concrete (i.e. heat waves and floods) or abstract events (i.e. temperature and precipitation). The results revealed that projections that included the 90% predictive interval were considered more trustworthy than deterministic projections. In addition, in a nationally representative sample, Republicans who were informed of concrete events with predictive intervals reported greater concern and more favorable attitudes toward climate scientists than when deterministic projections were used. Overall these findings suggest that while climate change beliefs may be rooted in partisan identity, they remain malleable, especially when targeted communication strategies are used.

Edit, the linked article entitled: "France’s record-breaking heatwave made ‘at least five times’ more likely by climate change", is an example of improved communication (to the general public) of climate risks:

https://www.carbonbrief.org/frances-record-breaking-heatwave-made-at-least-five-times-more-likely-by-climate-change

Extract: "The record-breaking heatwave that struck France last week was made at “least five times more likely” by climate change, according to a new quick-fire assessment."
« Last Edit: July 02, 2019, 11:11:09 PM by AbruptSLR »
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1288 on: July 02, 2019, 11:32:17 PM »
The linked reference provides paleo-information that during the last deglaciation '… that the divide initially thickened due to the deglacial rise in snowfall, and subsequently thinned in response to retreat of the ice-sheet margin. We use these data to evaluate several recently-published ice-sheet models at the Pirrit Hills and Whitmore Mountains.'  To me this increases the likelihood that with continued global warming, the projected increase in snowfall will likely increase the gravitational driving forces on the WAIS; which will likely acceleration glacial ice flow velocities; which will likely serve to acceleration the destabilization of the WAIS:

Spector, P., Stone, J., and Goehring, B.: Thickness of the divide and flank of the West Antarctic Ice Sheet through the last deglaciation, The Cryosphere Discuss., https://doi.org/10.5194/tc-2019-115, in review, 2019.

https://www.the-cryosphere-discuss.net/tc-2019-115/

Abstract. We report cosmogenic-nuclide measurements from two isolated groups of nunataks in West Antarctica: the Pirrit Hills, located midway between the grounding line and the divide in the Weddell Sea sector, and the Whitmore Mountains, located along the Ross-Weddell divide. At the Pirrit Hills, ice reached a highstand ~ 320 m above present during the last glacial period. Subsequent thinning mostly occurred after ~ 14 kyr B.P., and modern ice levels were established some time after ~ 4 kyr B.P. We infer that, like at other flank sites, these changes were primarily controlled by the position of the grounding-line downstream. At the Whitmore Mountains, cosmogenic 14C concentrations in bedrock surfaces demonstrate that ice there was no more than ~ 190 m thicker than present during the past ~ 30 kyr. Combined with other constraints from West Antarctica, the 14C data imply that the divide was thicker than present for a period of less than ~ 8 kyr within the past ~ 15 kyr. These results are consistent with the hypothesis that the divide initially thickened due to the deglacial rise in snowfall, and subsequently thinned in response to retreat of the ice-sheet margin. We use these data to evaluate several recently-published ice-sheet models at the Pirrit Hills and Whitmore Mountains.
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1289 on: July 02, 2019, 11:42:41 PM »
While I (personally) am not surprised that since 2014 the Antarctic sea ice extent has been decreasing at rates far exceeding the rates in the Arctic; nevertheless, it is worth noting that that is exactly what the linked reference has now documented.  Obviously, this is not good news w.r.t. increasing climate risks with continued global warming:

Claire L. Parkinson (July 1, 2019), "A 40-y record reveals gradual Antarctic sea ice increases followed by decreases at rates far exceeding the rates seen in the Arctic", PNAS, https://doi.org/10.1073/pnas.1906556116

https://www.pnas.org/content/early/2019/06/25/1906556116

Significance
A newly completed 40-y record of satellite observations is used to quantify changes in Antarctic sea ice coverage since the late 1970s. Sea ice spreads over vast areas and has major impacts on the rest of the climate system, reflecting solar radiation and restricting ocean/atmosphere exchanges. The satellite record reveals that a gradual, decades-long overall increase in Antarctic sea ice extents reversed in 2014, with subsequent rates of decrease in 2014–2017 far exceeding the more widely publicized decay rates experienced in the Arctic. The rapid decreases reduced the Antarctic sea ice extents to their lowest values in the 40-y record, both on a yearly average basis (record low in 2017) and on a monthly basis (record low in February 2017).

Abstract
Following over 3 decades of gradual but uneven increases in sea ice coverage, the yearly average Antarctic sea ice extents reached a record high of 12.8 × 106 km2 in 2014, followed by a decline so precipitous that they reached their lowest value in the 40-y 1979–2018 satellite multichannel passive-microwave record, 10.7 × 106 km2, in 2017. In contrast, it took the Arctic sea ice cover a full 3 decades to register a loss that great in yearly average ice extents. Still, when considering the 40-y record as a whole, the Antarctic sea ice continues to have a positive overall trend in yearly average ice extents, although at 11,300 ± 5,300 km2⋅y−1, this trend is only 50% of the trend for 1979–2014, before the precipitous decline. Four of the 5 sectors into which the Antarctic sea ice cover is divided all also have 40-y positive trends that are well reduced from their 2014–2017 values. The one anomalous sector in this regard, the Bellingshausen/Amundsen Seas, has a 40-y negative trend, with the yearly average ice extents decreasing overall in the first 3 decades, reaching a minimum in 2007, and exhibiting an overall upward trend since 2007 (i.e., reflecting a reversal in the opposite direction from the other 4 sectors and the Antarctic sea ice cover as a whole).
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1290 on: July 03, 2019, 12:33:13 AM »
Claire L. Parkinson (July 1, 2019), "A 40-y record reveals gradual Antarctic sea ice increases followed by decreases at rates far exceeding the rates seen in the Arctic", PNAS, https://doi.org/10.1073/pnas.1906556116



Shocking. Hopefully this largely represents increased variability rather than a new downward trend.

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1291 on: July 03, 2019, 04:51:34 PM »
The linked reference uses improved modeling of the stratospheric chemistry-climate interactions in the hot climate conditions of the Eocene and recommends that such improved modeling of the stratospheric chemistry be included in climate models projecting the future.  What is important to remember is that current consensus climate model projections of the future do not accurately account for stratosphere-climate interactions under hot climate conditions; which increases our collective climate risks:

Szopa, S., Thiéblemont, R., Bekki, S., Botsyun, S., and Sepulchre, P.: Role of the stratospheric chemistry–climate interactions in the hot climate conditions of the Eocene, Clim. Past, 15, 1187-1203, https://doi.org/10.5194/cp-15-1187-2019, 2019.

https://www.clim-past.net/15/1187/2019/

Abstract
The stratospheric ozone layer plays a key role in atmospheric thermal structure and circulation. Although stratospheric ozone distribution is sensitive to changes in trace gases concentrations and climate, the modifications of stratospheric ozone are not usually considered in climate studies at geological timescales. Here, we evaluate the potential role of stratospheric ozone chemistry in the case of the Eocene hot conditions. Using a chemistry–climate model, we show that the structure of the ozone layer is significantly different under these conditions (4×CO2 climate and high concentrations of tropospheric N2O and CH4). The total column ozone (TCO) remains more or less unchanged in the tropics whereas it is found to be enhanced at mid- and high latitudes. These ozone changes are related to the stratospheric cooling and an acceleration of stratospheric Brewer–Dobson circulation simulated under Eocene climate. As a consequence, the meridional distribution of the TCO appears to be modified, showing particularly pronounced midlatitude maxima and a steeper negative poleward gradient from these maxima. These anomalies are consistent with changes in the seasonal evolution of the polar vortex during winter, especially in the Northern Hemisphere, found to be mainly driven by seasonal changes in planetary wave activity and stratospheric wave-drag. Compared to a preindustrial atmospheric composition, the changes in local ozone concentration reach up to 40 % for zonal annual mean and affect temperature by a few kelvins in the middle stratosphere.
As inter-model differences in simulating deep-past temperatures are quite high, the consideration of atmospheric chemistry, which is computationally demanding in Earth system models, may seem superfluous. However, our results suggest that using stratospheric ozone calculated by the model (and hence more physically consistent with Eocene conditions) instead of the commonly specified preindustrial ozone distribution could change the simulated global surface air temperature by as much as 14 %. This error is of the same order as the effect of non-CO2 boundary conditions (topography, bathymetry, solar constant and vegetation). Moreover, the results highlight the sensitivity of stratospheric ozone to hot climate conditions. Since the climate sensitivity to stratospheric ozone feedback largely differs between models, it must be better constrained not only for deep-past conditions but also for future climates.
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1292 on: July 03, 2019, 04:54:17 PM »

Shocking. Hopefully this largely represents increased variability rather than a new downward trend.

It is good to remember that increasing climate variability is an indication of increasing climate sensitivity (i.e. increasing ECS), possibly due to increasingly positive ice-climate feedback mechanisms.
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1293 on: July 03, 2019, 05:25:56 PM »
Claire L. Parkinson (July 1, 2019), "A 40-y record reveals gradual Antarctic sea ice increases followed by decreases at rates far exceeding the rates seen in the Arctic", PNAS, https://doi.org/10.1073/pnas.1906556116



Shocking. Hopefully this largely represents increased variability rather than a new downward trend.

It turns out that over 40 years, the area of sea ice in the Southern Hemisphere has grown on average by about 5 percent (or this is less, taking into account the continuation of the latest trend in 2019).

For comparison, according to the observations of whalers in the 20th century, a sharp drop in the ice area by 25% was observed.

http://www.ccpo.odu.edu/~klinck/Reprints/PDF/delamareNature1997.pdf



Quote
The southern limit of whaling was constrained by sea ice, and since 1931 whaling records have been collected for every whale caught7, giving a circumpolar coverage from spring to autumn until 1987. Here, an analysis of these catch records indicates that, averaged over October to April, the Antarctic summer sea-ice edge has moved southwards by 2.88 of latitude between the mid 1950s and early 1970s. This suggests a decline in the area covered by sea ice of some 25%.

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1294 on: July 03, 2019, 11:44:13 PM »
The linked reference indicates that for projected increases in air traffic, between 2006 and 2050, contrail cirrus radiative forcing will increase 3-fold, from 49 to 159 mW m−2.  Such a large increase is currently not included in consensus climate model projections such as AR5:

Bock, L. and Burkhardt, U.: Contrail cirrus radiative forcing for future air traffic, Atmos. Chem. Phys., 19, 8163-8174, https://doi.org/10.5194/acp-19-8163-2019, 2019.

https://www.atmos-chem-phys.net/19/8163/2019/

Abstract

The climate impact of air traffic is to a large degree caused by changes in cirrus cloudiness resulting from the formation of contrails. Contrail cirrus radiative forcing is expected to increase significantly over time due to the large projected increases in air traffic. We use ECHAM5-CCMod, an atmospheric climate model with an online contrail cirrus parameterization including a microphysical two-moment scheme, to investigate the climate impact of contrail cirrus for the year 2050. We take into account the predicted increase in air traffic volume, changes in propulsion efficiency and emissions, in particular soot emissions, and the modification of the contrail cirrus climate impact due to anthropogenic climate change.

Global contrail cirrus radiative forcing increases by a factor of 3 from 2006 to 2050, reaching 160 or even 180 mW m−2, which is the result of the increase in air traffic volume and a slight shift in air traffic towards higher altitudes. Large increases in contrail cirrus radiative forcing are expected over all of the main air traffic areas, but relative increases are largest over main air traffic areas over eastern Asia. The projected upward shift in air traffic attenuates contrail cirrus radiative forcing increases in the midlatitudes but reinforces it in the tropical areas. Climate change has an insignificant impact on global contrail cirrus radiative forcing, while regional changes are significant. Of the emission reductions it is the soot number emission reductions by 50 % that lead to a significant decrease in contrail cirrus optical depth and coverage, leading to a decrease in radiative forcing by approximately 15 %. The strong increase in contrail cirrus radiative forcing due to the projected increase in air traffic volume cannot be compensated for by the decrease in initial ice crystal numbers due to reduced soot emissions and improvements in propulsion efficiency.
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1296 on: July 05, 2019, 01:59:53 PM »
Tom that is a great article for the Places becoming Less Liveable thread.

Ocean water has contaminated much of the island’s meager freshwater supply and left 70 percent of Mousuni’s land too salty to farm, destroying the majority of its inhabitants’ livelihoods.

This is a problem in so many places. All these people will move at some point...
Þetta minnismerki er til vitnis um að við vitum hvað er að gerast og hvað þarf að gera. Aðeins þú veist hvort við gerðum eitthvað.

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1297 on: July 06, 2019, 05:50:13 PM »
Tom that is a great article for the Places becoming Less Liveable thread.

Ocean water has contaminated much of the island’s meager freshwater supply and left 70 percent of Mousuni’s land too salty to farm, destroying the majority of its inhabitants’ livelihoods.

This is a problem in so many places. All these people will move at some point...

Sorry, kassy.
I tend to be very busy (although I am on Disability) and don't always have time to pick out the one perfect thread...  :-[

AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1298 on: July 07, 2019, 04:34:45 AM »
The linked article points out that as sea level continues to rise, the groundwater levels beneath coastal areas will also rise, and those areas subject to strong ground motion may be subjected to liquefaction of the soil:

Title: "An Ancient City’s Demise Hints at a Hidden Risk of Sea-Level Rise"

https://www.theatlantic.com/science/archive/2019/06/earthquakes-and-sea-level-rise-are-deadly-combination/592945/

Extract: "Two millennia ago, an earthquake liquefied the ground beneath the Egyptian port of Thonis-Heracleion.

Even the smallest increase in the level of a local water table can raise a city’s risk of liquefaction. If a modern-day Thonis-Heracleion were to experience floods—say, worse than usual, thanks to rising seas—and then suffer a quake, the devastation could be cataclysmic, sending dozens or even hundreds of structures crashing down within seconds. That’s the promise of sea-level rise in many liquefaction-vulnerable places. Little by little, the water table rises, and after one flood, a quake comes, and the soil turns to liquid, to a weakened goo incapable of supporting the heavy brick and steel and broad wood beams erected upon it."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1299 on: July 07, 2019, 04:40:52 AM »
The linked article makes it clear that the booming LNG industry will make it harder to meet the Paris goals:

Title: "Booming LNG industry could be as bad for climate as coal, experts warn"

https://www.theguardian.com/environment/2019/jul/03/booming-lng-industry-could-be-as-bad-for-climate-as-coal-experts-warn

Extract: "Liquefied natural gas developments on a collision course with Paris agreement, Global Energy Monitor says"
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson