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AbruptSLR

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Re: Carbon Cycle
« Reply #300 on: May 23, 2016, 06:28:14 PM »
The linked reference concludes that via changes in the carbon cycle: "Overall our results suggest that the longer emissions of non-CO2 forcing agents persists the greater effect these agents will have on global climate."

Andrew H. MacDougall & Reto Knutti (18 May 2016), "Enhancement of non-CO2 radiative forcing via intensified carbon cycle feedbacks", Geophysical Research Letters, DOI: 10.1002/2016GL068964

http://onlinelibrary.wiley.com/doi/10.1002/2016GL068964/abstract

Abstract: "The global carbon cycle is sensitive to changes in global temperature and atmospheric CO2 concentration, with increased temperature tending to reduce the efficiency of carbon sinks and increased CO2 enhancing the efficiency of carbon sinks. The emission of non-CO2 greenhouse gases warms the Earth but does not induce the CO2 fertilization effect or increase the partial-pressure gradient between the atmosphere and the surface ocean. Here we present idealized climate model experiments that explore the indirect interaction between non-CO2 forcing and the carbon cycle. The experiments suggest that this interaction enhances the warming effect of the non-CO2 forcing by up to 25% after 150 years and that much of the warming caused by these agents lingers for over 100 years after the dissipation of the non-CO2 forcing. Overall our results suggest that the longer emissions of non-CO2 forcing agents persists the greater effect these agents will have on global climate."
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Bruce Steele

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Re: Carbon Cycle
« Reply #301 on: May 29, 2016, 07:38:10 PM »
The following link does have a section on carbon cycling and can be posted here but it would probably better if it had a home on a freshwater input page. It is a very nice summary of many subjects and a very recent open source offering.
 The focus is freshwater inputs to the Arctic.

http://onlinelibrary.wiley.com/doi/10.1002/2015JG003140/full

Sigmetnow

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Re: Carbon Cycle
« Reply #302 on: June 16, 2016, 01:55:07 AM »

Alpine soils storing up to a third less carbon as summers warm
Quote
The top metre of the world’s soils contains three times as much carbon as the entire atmosphere. This means that losing carbon from the soil can quicken the pace of human-caused climate warming.

A new paper, published today in Nature Geoscience, finds this is already happening in the forests of the German Alps. Soils there are losing carbon as summer temperatures rise, the researchers say.

In the last three decades, soil carbon across the German Alps has decreased by an average of 14% – and by as much as 32% for certain types of soils.

The findings might be a sign of how soils could amplify warming in future, other scientists say.
http://www.carbonbrief.org/alpine-soils-storing-up-to-a-third-less-carbon-as-summers-warm
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AbruptSLR

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Re: Carbon Cycle
« Reply #303 on: July 11, 2016, 05:30:50 PM »
The linked article discusses how the impacts of ocean acidification may be more widespread and may last longer (multiple centuries) than most people think:

http://www.latimes.com/science/sciencenow/la-sci-sn-phytoplankton-acidic-oceans-20160708-snap-story.html
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AbruptSLR

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Re: Carbon Cycle
« Reply #304 on: July 20, 2016, 10:50:32 AM »
The linked article indicates that new research suggests that the Chesapeake Bay annually generates as much methane as all other estuaries in the world combined:

http://www.dailypress.com/news/science/dp-nws-chesapeake-bay-methane-20160719-story.html
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AbruptSLR

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Re: Carbon Cycle
« Reply #305 on: July 25, 2016, 09:24:09 PM »
The linked reference focuses on carbon cycle feedback mechanisms when discussing uncertainties in future projections of these cycles in Earth System Model projections.  The reference indicates that relatively high model uncertainty still exist in land carbon cycle, and in some key regional (like the North Atlantic & Southern Ocean) ocean carbon cycle, fluxes.

Alan J. Hewitt, Ben B. B. Booth, Chris D. Jones, Eddy S. Robertson, Andy J. Wiltshire, Philip G. Sansom, David B. Stephenson & Stan Yip (July 2016), "Sources of uncertainty in future projections of the carbon cycle", Journal of Climate, DOI: http://dx.doi.org/10.1175/JCLI-D-16-0161.1

http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-16-0161.1

Abstract: "The inclusion of carbon cycle processes within CMIP5 Earth System Models provides the opportunity to explore the relative importance of differences in scenario and climate model representation to future land and ocean carbon fluxes. A two-way ANOVA approach was used to quantify the variability owing to differences between scenarios and between climate models at different lead times.

For global ocean carbon fluxes, the variance attributed to differences between Representative Concentration Pathway scenarios exceeds the variance attributed to differences between climate models by around 2025, completely dominating by 2100. This contrasts with global land carbon fluxes, where the variance attributed to differences between climate models continues to dominate beyond 2100. This suggests that modelled processes that determine ocean fluxes are currently better constrained than those of land fluxes, thus we can be more confident in linking different future socio-economic pathways to consequences of ocean carbon uptake than for land carbon uptake. The contribution of internal variance is negligible for ocean fluxes and small for land fluxes, indicating that there is little dependence on the initial conditions.

The apparent agreement in atmosphere-ocean carbon fluxes, globally, masks strong climate model differences at a regional level. The North Atlantic and Southern Ocean are key regions, where differences in modelled processes represent an important source of variability in projected regional fluxes."
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AbruptSLR

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Re: Carbon Cycle
« Reply #306 on: July 29, 2016, 11:41:03 PM »
The linked article is entitled: "Soil microbes burp carbon dioxide after drought-breaking rain", and it discusses a little understood carbon cycle feedback:

http://www.abc.net.au/radionational/programs/scienceshow/soil-microbes-burp-co2-after-drought-breaking-rain/7652800

Extract: "An unpredictable source of carbon emissions in areas of sporadic rainfall, is the carbon dioxide released from soil when rain falls after drought. The emissions come from soil microbes, and as Catherine Osborne explains, these critters are very difficult to study. But recent advances in DNA sequencing technology have made things easier. In her work at the University of California Berkeley, Catherine investigated soil microbes."
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AbruptSLR

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Re: Carbon Cycle
« Reply #307 on: August 03, 2016, 05:17:51 AM »
AR5 downplayed the importance of soil carbon feedbacks, but now "A new Yale-led paper makes the case that developing meaningful climate projections will rely on understanding the role of "soil carbon turnover" and how it might potentially trigger climate feedbacks in a warming world.":

Mark A. Bradford,   William R. Wieder,   Gordon B. Bonan,   Noah Fierer,   Peter A. Raymond   & Thomas W. Crowther (2016), "Managing uncertainty in soil carbon feedbacks to climate change", Nature Climate Change 6, 751–758, doi:10.1038/nclimate3071

http://www.nature.com/nclimate/journal/v6/n8/full/nclimate3071.html

Abstract: "Planetary warming may be exacerbated if it accelerates loss of soil carbon to the atmosphere. This carbon-cycle–climate feedback is included in climate projections. Yet, despite ancillary data supporting a positive feedback, there is limited evidence for soil carbon loss under warming. The low confidence engendered in feedback projections is reduced further by the common representation in models of an outdated knowledge of soil carbon turnover. 'Model-knowledge integration' — representing in models an advanced understanding of soil carbon stabilization — is the first step to build confidence. This will inform experiments that further increase confidence by resolving competing mechanisms that most influence projected soil-carbon stocks. Improving feedback projections is an imperative for establishing greenhouse gas emission targets that limit climate change."

See also:
http://phys.org/news/2016-08-uncertainty-soil-carbon-feedbacks-affect.html

Extract: "Warming temperatures can trigger two very different changes in soil carbon soil levels. On the one hand, they can stimulate the growth of plants, increasing the amount of carbon storage potential. Conversely, those higher temperatures can also accelerate the activity of organisms that live in the soil and consume decaying plant matter. In that case, there is a net increase in the amount of carbon released from the biosphere into the atmosphere.

In other words, one function puts carbon into the soil, keeping it out of the atmosphere, while the other emits it into the atmosphere. The twist, however, is that the processes that emit carbon from the soil also convert a small fraction of the decaying plant matter into stores of carbon that can be locked away over millennial timescales, which would be optimal to minimizing climate impacts."
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AbruptSLR

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Re: Carbon Cycle
« Reply #308 on: August 22, 2016, 07:03:32 PM »
It seems to me that the annual trend for increasing atmospheric CH4 concentration at Barrow Alaska is beginning early (starting in mid-June) this year:
« Last Edit: August 23, 2016, 08:41:29 PM by AbruptSLR »
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Bruce Steele

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Re: Carbon Cycle
« Reply #309 on: August 23, 2016, 08:20:13 PM »
I like to post papers on the biological effects of ocean acidification here in the Calif. Current Ecosystem. The CCE is an eastern boundary upwelling system that has pCo2 , pH and biological impacts of acidification that precede conditions in most other oceans of the world. The base of the food chain is an important place to keep an eye on because negative changes there will cascade up through trophic levels to fish, birds and mammals ( including humans ). There have been studies documenting negative effects on Pteropods under current conditions and now Krill can be added to the list of negatively effected species under current conditions.

  http://www.int-res.com/articles/meps_oa/m555p065.pdf

Bruce Steele

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Re: Carbon Cycle
« Reply #310 on: August 23, 2016, 08:27:12 PM »
Development of Euphausia pacifica (krill) larvae is impaired under pCO2 levels currently observed in the Northeast Pacific
Despite the critical importance of euphausiids in marine food webs, little ocean acidification (OA) research has focused on them. Euphausia pacifica is a dominant and trophically important species of euphausiid throughout the North Pacific and the California Current Ecosystem, where low pH conditions are occurring in advance of those in the global ocean. We assessed the impact of reduced pH on the hatching and larval development of E. pacifica in the laboratory and characterized the pH to which E. pacifica eggs and larvae are currently exposed in Puget Sound, Washington (USA), a large estuary connected to the California Current. In 2 independent sets of laboratory experiments that lasted 6 to 22 d and which involved broods from 110 different females, we found that hatching is robust to a wide range of pH levels, but larval development and survival are reduced at pH levels that are currently observed within their habitat. Survival from 3 d post hatch to the calyptopis 2 stage was reduced by an average of 20% at pH 7.69 compared to pH 7.96. Even though this population experiences a range of pH conditions on seasonal and daily timescales, it may be living near the limits of its pH tolerance. Continued OA may push these organisms past their threshold, which could have cascading negative consequences for higher trophic levels.

AbruptSLR

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Re: Carbon Cycle
« Reply #311 on: September 22, 2016, 12:46:10 AM »
The linked pdf presents abstracts from the recent "12th International Conference on Paleoceanography: 29 August – 2 September 2016, Utrecht, the Netherlands.  As I am traveling, I have not had time to review the numerous abstracts.

http://icp12.uu.nl/wp-content/uploads/2016/08/Poster-abstracts-sessie-3.pdf

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Bruce Steele

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Re: Carbon Cycle
« Reply #312 on: September 22, 2016, 11:14:54 PM »
"Hopes that large amounts of planet-warming carbon dioxide could be buried in soils appear to be grossly misplaced, with new research finding that the ground will soak up far less carbon over the coming century than previously thought."

If soil is a much smaller / slower carbon sink than previously thought we are left with very few options other than the oceans.  Maybe it's high time to get honest about what carbon sinks we have at our disposal and concentrate on sinks that can operate in timeframes we are pushing.Understanding ocean carbon sinks seems a good place to start. Those processes that result in carbonate sedimentation at coastal shelf depths or expanded farming of kelp that is harvested and removed from the ocean are two places to put extra efforts.

https://www.theguardian.com/environment/2016/sep/22/soil-carbon-storage-not-the-climate-change-fix-it-was-thought-research-finds

AbruptSLR

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Re: Carbon Cycle
« Reply #313 on: September 23, 2016, 01:16:02 AM »
Abstract P-422 indicates the current ESMs modeling of the "Biological Pump" does not fully match the paleo record; while abstract P-406 indicates that global warming can weaken the "Biological Pump".  Taken together, these findings raise the risk that parts of the ocean (particularly the Southern Ocean) could become sources of net carbon venting rather than net carbon absorption, with continued global warming:

http://icp12.uu.nl/wp-content/uploads/2016/08/Poster-abstracts-sessie-3.pdf

P-422
Sensitivity of atmospheric CO2 and the marine carbon cycle to the Biological Pump
Jamie Wilson, School of Geographical Sciences, University of Bristol, United Kingdom
(jamie.wilson@bristol.ac.uk)
Sarah E. Greene, University of Bristol, UK
The exchange of CO2 between the ocean and the atmosphere is strongly mediated by the fate of organic carbon formed by phytoplankton the 'Biological Pump'). Organic carbon is exported as sinking particles that are degraded in the water column and buried at the seafloor. Modern field and laboratory observations suggest that organic fluxes are influenced by various environmental conditions, including (but not limited to!) temperature. For example, colder temperatures during glacial periods are hypothesized to have reduced the export of organic carbon but also slowed its degradation in the water column. Key questions remain such as: Which aspects of the biological pump is atmospheric pCO2 most sensitive to? Are there feedbacks between biological pump processes and what timescales do they operate? These questions have significance for interpreting palaeoclimate proxies and informing future climate predictions.
Here we present results using the Earth system model cGENIE to quantify the sensitivity of pCO2 and the marine carbon cycle to mechanistic uncertainties in controls on the biological pump. We systematically vary three key processes (export, remineralisation, and reactivity) to explore the different hypothetical modes of operation of the biological pump over different timescales. We show that the sensitivity of pCO2 to individual processes and their interactions is dependent on the timescale considered due to deep-sea CaCO3 sediment feedbacks. We also demonstrate that some modes of operation are contradicted by the deep-sea CaCO3 record, demonstrating how palaeoclimate can be used to constrain biological pump processes of critical importance for modern and future modelling.

P-406
A rise in Southern Ocean overturning over the Holocene
Anja Studer, Climate Geochemistry, Max Planck Institute for Chemistry, Germany
(anja.studer@mpic.de)
Daniel M. Sigman, Princeton University, Princeton, NJ, USA; Alfredo Martinez-Garcia, Max Planck Institute for Chemistry, Mainz, Germany; Lena M. Thöle, Institute of Geological Sciences and Oeschger Center for Climate Change Research, University of Bern, Bern, Switzerland; Elisabeth Michel, Laboratoire des Sciences du Climat et de l'Environnement, Gif-sur-Yvette Cedex, France; Samuel L. Jaccard, Institute of Geological Sciences and Oeschger Center for Climate Change Research, University of Bern, Bern, Switzerland; Jörg Lippold, Institute of Geological Sciences and Oeschger Center for Climate Change Research, University of Bern, Bern, Switzerland; Alain Mazaud, Laboratoire des Sciences du Climat et de l'Environnement, Gif-sur-Yvette Cedex, France; Xingchen T. Wang, Princeton University, Princeton, NJ, USA; Gerald H. Haug, Max Planck Institute for Chemistry, Mainz, Germany;
Over the course of the Holocene, the ongoing 11,700 year-long interglacial period, the concentration of atmospheric carbon dioxide (CO2) rose by ~20 ppm. This CO2 rise is of particular importance for assessing the sensitivity of climate in its current state, but its cause remains a mystery. From three sediment cores in the Antarctic Zone of the Southern Ocean, we report diatom-bound nitrogen isotope measurements that indicate rising surface nitrate concentration throughout the Holocene, pointing to an acceleration in Antarctic overturning. As the combined physical and biogeochemical changes would have weakened the ocean’s “biological pump” that stores CO2 in the ocean interior, these data provide the first direct evidence for a change that would have worked to explain the Holocene atmospheric CO2 rise.
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GeoffBeacon

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Re: Carbon Cycle
« Reply #314 on: September 23, 2016, 10:56:42 AM »
There was conference “1.5C conference on climate change”, organised by the Environmental Change Institute at the University of Oxford. Carbon Brief reports a view that carbon budgets are much too pessimistic

Quote
Prof Pierre Friedlingstein, chair of mathematical modelling of climate systems at the University of Exeter, suggested the estimate that there are five years worth of current emissions left before we exceed the carbon budget to stay under 1.5C is too pessimistic. Accounting for the fact that the cumulative warming per unit of carbon dioxide observed recently is lower than in the majority of climate models extends the 1.5C budget timeline to 20-30 years.

Is this realistic? Is there any published material, peer-reviewed or otherwise?
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GeoffBeacon

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Re: Carbon Cycle
« Reply #315 on: September 23, 2016, 11:37:16 AM »
Professor Friedlingstein has kindly replied to an email. The report reflects his views. Writing it up is top of his list.
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AbruptSLR

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Re: Carbon Cycle
« Reply #316 on: September 23, 2016, 11:39:09 AM »
There was conference “1.5C conference on climate change”, organised by the Environmental Change Institute at the University of Oxford. Carbon Brief reports a view that carbon budgets are much too pessimistic

Quote
Prof Pierre Friedlingstein, chair of mathematical modelling of climate systems at the University of Exeter, suggested the estimate that there are five years worth of current emissions left before we exceed the carbon budget to stay under 1.5C is too pessimistic. Accounting for the fact that the cumulative warming per unit of carbon dioxide observed recently is lower than in the majority of climate models extends the 1.5C budget timeline to 20-30 years.

Is this realistic? Is there any published material, peer-reviewed or otherwise?

First, I note that through the end of August 2016 that we are currently at 1.3C above pre-industrial.

Second, I provide the following ESLD reference (including several authors that developed the RCP scenarios) that confirms that the true carbon budget is actually much lower than previously believed:

Joeri Rogelj, Michiel Schaeffer, Pierre Friedlingstein, Nathan P. Gillett, Detlef P. van Vuuren, Keywan Riahi, Myles Allen & Reto Knutti (2016), "Differences between carbon budget estimates unraveled", Nature Climate Change, Volume: 6, Pages: 245–252, doi:10.1038/nclimate2868


http://www.nature.com/nclimate/journal/v6/n3/full/nclimate2868.html

Abstract: "Several methods exist to estimate the cumulative carbon emissions that would keep global warming to below a given temperature limit. Here we review estimates reported by the IPCC and the recent literature, and discuss the reasons underlying their differences. The most scientifically robust number — the carbon budget for CO2-induced warming only — is also the least relevant for real-world policy. Including all greenhouse gases and using methods based on scenarios that avoid instead of exceed a given temperature limit results in lower carbon budgets. For a >66% chance of limiting warming below the internationally agreed temperature limit of 2 °C relative to pre-industrial levels, the most appropriate carbon budget estimate is 590–1,240 GtCO2 from 2015 onwards. Variations within this range depend on the probability of staying below 2 °C and on end-of-century non-CO2 warming. Current CO2 emissions are about 40 GtCO2 yr−1, and global CO2 emissions thus have to be reduced urgently to keep within a 2 °C-compatible budget."

See also:
http://ecowatch.com/2016/02/26/world-carbon-budget/

Extract: "There is general agreement that a limit of 590 billion tons would safely keep the world from overheating in ways that would impose ever greater strains on human society. The argument is about the upper limit of such estimates.

Dr. Rogelj said:
“In order to have a reasonable chance of keeping global warming below 2 C, we can only emit a certain amount of carbon dioxide, ever. That’s our carbon budget.
“This has been understood for about a decade and the physics behind this concept are well understood, but many different factors can lead to carbon budgets that are either slightly smaller or slightly larger. We wanted to understand these differences and to provide clarity on the issue for policy-makers and the public.
“This study shows that, in some cases, we have been overestimating the budget by 50 to more than 200 percent. At the high end, this is a difference of more than 1,000 billion tons of carbon dioxide.”
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GeoffBeacon

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Re: Carbon Cycle
« Reply #317 on: September 23, 2016, 03:48:27 PM »
ALSR

Thanks. What is odd is that it was a conference organised by the Environmental Change Institute at the University of Oxford, Where Myles Allen is "Leader, Climate Research Programme". I suspect he will have been part of organising the conference.

As well as Myles Allen, another of the authors of the paper you quote, Joeri Rogelj, was present. He is on the video of the report of the first day.

You can see my comments at the end, which start

Quote
[1] In the video, Professor Corrinne Le Quere says [to keep within 1.5°C] it is necessary to be “completely de-carbonising the economy in just a few decades."
Earlier this year Carbon Brief said “Analysis: Only five years left before 1.5°C carbon budget is blown”. There is a big difference between “a few decades” and five years.

[2] Corrine also says “Global emissions have stalled in the past few years”. Apart from the fact that “stalled” is nowhere good enough, this reduction is not yet seen in the increasing concentrations of CO2 in the atmosphere(2).

There were others in the “a few decades” to de-carbonise camp, something I'm sure I've heard the same implied at presentations at the London School of Economics recently.

Another thing is time scales.

Quote
Before the science talks, Dr Anna Pirani, head of the IPCC’s Working Group 1 Technical Support Unit, reminded everyone of the short timeline they’re working to. To be assessed in the IPCC’s special report on 1.5°C, papers must be submitted by October 2017 and accepted by April 2018.


The report is two years off (at least?). So that means three years of remaining carbon budget for 1.5°C.

What are we to believe about the remaining budget?

P.S. Five years means that we need degrowth. The politics of that are awful.

Two or three decades is a lot of long grass to hide in.



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AbruptSLR

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Re: Carbon Cycle
« Reply #318 on: September 23, 2016, 05:07:59 PM »

What are we to believe about the remaining budget?

P.S. Five years means that we need degrowth. The politics of that are awful.

Two or three decades is a lot of long grass to hide in.

Those in authority (scientific or policy-wise) will never acknowledge the true risks of high climate sensitivity (including early temperature rise), as then there would no longer be grass to hide in.  The linked articles indicate that "experts" that we will exceed 1.5C in less than tens years; however, if ECS is 4.6C that might be less than five years:

http://www.reuters.com/article/us-climatechange-impacts-conference-idUSKCN11S1FE

See also:

https://www.yahoo.com/news/experts-see-few-paths-planet-saving-climate-goal-004414242.html


Extract: "For many scientists, 1.5 C seems virtually impossible -- at least not without "over-shooting" the target.

"We may see the first year of 1.5 C above pre-industrial levels within a decade," cautioned Richard Betts, head of climate impacts research at the Met Office Hadley Centre in England."
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AbruptSLR

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Re: Carbon Cycle
« Reply #319 on: September 23, 2016, 05:43:15 PM »
The linked article indicates that telling policy makers the truth (that exceeding 1.5C will cause serious damage and that we are likely to pass this target sooner rather than later) is dangerous because they only know how to react with geoengineering as a response to such "bad news", rather than reacting by co-operating together to cut emissions.  So damned if you do, damned if you don't. 

Furthermore, the first attached image of daily GMST anom values through Sept 20 2016, shows that the anom for Sept is increasing compared to projections, and the second attached image shows the daily Nino 3.4 values thru today, indicate that the chances of La Nina occurring anytime soon is decreasing by the day:

https://www.theguardian.com/environment/2016/sep/22/paris-climate-goal-will-de-difficult-if-not-impossible-to-hit

Extract: "For some scientists, even setting the target is a bad idea.
“There is a risk that the 1.5C temperature threshold is a distraction,” said Kevin Anderson, deputy director of the Tyndall Centre for Climate Research in England.


“The danger is that it will push us to look at geoengineering solutions rather than how to achieve deep decarbonisation.”"
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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jai mitchell

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Re: Carbon Cycle
« Reply #320 on: September 24, 2016, 08:23:14 PM »
RadioCarbon Dating of soil-sequestered carbon indicates that carbon uptake to soil (in some cases) is 1/6th as rapid as many models hold - This reduces the likely century-scale carbon sequestration to soil by as much as 1/2 through 2100.

https://www.washingtonpost.com/news/energy-environment/wp/2016/09/22/the-earth-is-soaking-up-less-carbon-than-we-thought-which-means-global-warming-may-go-faster/

The Earth is soaking up less carbon than we thought — which could make it warm up even faster

Quote
In any case, the results suggest the process can take a lot longer than scientists previously assume — up to thousands of years, instead of just tens or hundreds. This means that previous research may have significantly overestimated how much carbon the world’s soil can store away throughout the rest of the century. In fact, the new study suggests that, worldwide, soil’s carbon sequestration potential this century may only be half what we thought it was.

Study here (science)

http://science.sciencemag.org/content/353/6306/1419
Radiocarbon constraints imply reduced carbon uptake by soils during the 21st century
Yujie He

Abstract

Soil is the largest terrestrial carbon reservoir and may influence the sign and magnitude of carbon cycle–climate feedbacks. Many Earth system models (ESMs) estimate a significant soil carbon sink by 2100, yet the underlying carbon dynamics determining this response have not been systematically tested against observations. We used 14C data from 157 globally distributed soil profiles sampled to 1-meter depth to show that ESMs underestimated the mean age of soil carbon by a factor of more than six (430 ± 50 years versus 3100 ± 1800 years). Consequently, ESMs overestimated the carbon sequestration potential of soils by a factor of nearly two (40 ± 27%). These inconsistencies suggest that ESMs must better represent carbon stabilization processes and the turnover time of slow and passive reservoirs when simulating future atmospheric carbon dioxide dynamics.



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Bruce Steele

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Re: Carbon Cycle
« Reply #321 on: September 25, 2016, 12:35:50 AM »
Jai, Thanks for the science magazine link that wasn't available in the Guardian piece I posted a couple days ago. This news is another ( Oh sh.. ) moment for me .  I have always thought there was a division of half of emissions to the atmosphere  a quarter to the terrestrial sinks and a quarter to the ocean sinks.  These numbers are admittedly general and now obviously erroneous. The oceans are somehow going to need to increase carbon sequestration from anthropogenic emissions and I fear they do not have the ability to do so at anywhere near the rate needed to avoid increasing atmospheric levels  at ever increasing rates. Hockey stick indeed !

Bruce Steele

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Re: Carbon Cycle
« Reply #322 on: September 25, 2016, 01:40:13 AM »
I wrote a letter about my recollection of changes I have seen in the ocean over the last thirty years. To me it shows the ocean and it's inhabitants are already having trouble related to increased heat and acidification.  These aren't problems in the future they are problems that have been escalating over the last three decades. To date the response has been to shut down fisheries and increase closed fishing areas to compensate for decreasing ocean health. Although this may buy some time for species negatively effected it in no way addresses societies continued carbon emissions or the false notion that we have a remaining carbon budget . We are past the point of doing damage to our ocean environment and past the point of carbon sinks ability to sequester more anthropogenic carbon emissions.

  My story starts when Halley's comet made it's last visit. My friends Steve , Lennard and I were diving abalone at Gull Island . After diving enough repetitive dives out deep we decided to go visit a shallow spot . I knew a rock pile that usually had a few Pink abalone and Black abalone in shallow. There was an El Nino in 
82-83 and it had brought with it some disease  trouble for abalone and when we threw the anchor on the shallow spot we couldn't believe what we saw because all the abalone were dead, there were just thousands of empty shells. It was 1986 and we were witnessing a disease event later to be named withering foot syndrome and it would eventually cause over 90% mortality in seven different abalone species and close the commercial abalone fishery. It was a harbinger of things to come. Stress caused by a strong El Nino and very hot water allowed an opportunistic viral disease to get a foothold at Gull Island that eventually spread throughout all of Southern California waters and wiped out the abalone stocks.
 When the next big El Nino arrived in 97-98 the abalone were finished off and I watched another disease ravage the starfish populations around the Channel Islands. There was also a large die off of purple urchins. Heat stress and climate change were starting to show up as disease events that came with the temperature spikes that El Nino delivered. The starfish wasting syndrome reappeared in 2014, 15 & 16 and took down multiple starfish stocks from Canada to the Mexican boarder. It also hit the purple urchins like before but this time it also began to kill large numbers of Red Sea urchins. With the starfish virtually gone purple urchins had a spectacular recruitment event , especially in Northern California , and as a result without the starfish predators to contain the purple urchins vast areas turned into urchin barrens.
       Maybe the hazardous algae bloom that arrived 2011 on the Sonoma Coast was an outlier or maybe it too will reappear to kill off more abalone, sea urchins and other intertidal mollusks. It wasn't associated  with El Nino like many of the other problems i have been describing but it's multi-species toxicity caused a lot of damage in a fairly limited area. .Hazardous algae blooms like the diatom Psedo-nitzschia do seem to be progressively getting larger and more toxic. Whether that is heat related , the largest outbreaks also correspond to the three El Nino events I described, or due to the effects of acidification is something time will tell . Lab studies do show the toxicity of Domoic acid increases with acidification. Last year major portions of the dungeness and rock crab fisheries seasons were closed. We can't make very good predictions yet but lobster may also be added to that list over the next few years.
 I am trying to stress that climate change , increased water temperatures and acidification are collectively doing a lot of damage to invertebrates as well as bird and mammal mortalities associated with toxic algae blooms. Heat in inland waters,drought, and water diversions for agriculture and cities have severely reduced anadromous fish stocks. Acidification is currently causing negative effects on pteropods during spring upwelling season along the northern California and Oregon
Coasts and in the Puget sound it is also likely doing damage to dungeness crab recruitment, krill abundance as well as pteropod populations and abundance.
 None of the issues I am describing will be reduced by enormous efforts at closing fishing grounds for refuges. These are systemic issues that can only be reduced by reducing societies carbon emissions . These carbon reductions will come at a price to economic growth and they need to be dramatic reductions worldwide.
Making fishermen scapegoats for societal ills , excluding us from from planning processes for dealing with these issues and generally painting us a pariahs is not going to solve these problems. In the end you won't even have anyone  able to tell the story about how the oceans died.  That is what is happening however and fishermen are just the canary in the coal mine.              
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Re: Carbon Cycle
« Reply #323 on: September 25, 2016, 10:06:49 PM »
The figure attached is from Scripps CO2 program page.

Solid Curve: Observed increase in atmospheric CO2 in units of PgC

Dashed Curve: Cumulative production of industrial CO2 from fossil fuel and cement versus time in units of PgC.

Under what assumptions regarding the carbon cycle and future emissions of CO2 would it be correct to interpret the figure as a forecast, where CO2 already emmitted from fossil fuel and cement will force the atmospheric CO2 to rise by about 140 PgC (the difference between the two curves in September 2016) in <20 years time ?

There is obviously a strong correlation between the two curves, although it would be more correct to illustrate accumulative trends over time with a logarithmic diagram.


« Last Edit: September 25, 2016, 10:16:07 PM by Hefaistos »

Bruce Steele

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Re: Carbon Cycle
« Reply #324 on: September 26, 2016, 01:40:27 AM »
Hefaistos, Both terrestrial and ocean sinks absorb part  ( about half ) of annual anthropogenic carbon emissions. So cumulative atmospheric increases are less than total emissions. Calculating future atmospheric levels is dependent upon the efficacy of both terrestrial and oceanic sinks as well as future trends in wildfire , and agricultural patterns. We are also putting a lot of stress on oceanic carbon sinks so predicting continued increases in the amount of CO2 that the ocean is capable of sustaining should be framed with increasing amounts of uncertainty.
 There is also methane, HFC's, NO2 and increased water vapor that are additive to CO2 in net effective
warming that aren't included in the Scripps CO2 figures graphed.
 I think there is more uncertainty in how our land and ocean sinks will respond than science might lead you to believe. The 40% miscalculation of the soil carbon sink is illustrative of this uncertainty. There is plenty of evidence to lead one to believe things might be in worse shape than conventional science might lead you to believe.  Predictions should be taken with a grain of salt, mine or anyone else's.


Hefaistos

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Re: Carbon Cycle
« Reply #325 on: September 26, 2016, 09:31:30 AM »
Bruce, thanks for your input. I'm well aware of the sinks and their role in the carbon cycle. What strikes me with this graph is the relationship between accelerating emissions and accelerating levels of CO2 in the atmosphere. What's scaring with this development, is that it's happening as we're speaking, it's totally unstoppable, and that it might cause a continued rapid temperature increase on earth even in the near term (20 years).

As a rule of thumb, it seems we can translate 1 PgC into 0.5 ppm of CO2. So if we have emmissions of 140 PgC 'unaccounted' for in terms of future ppm growth (due to delays involved in the carbon cycle), we'd end up with at least 470 ppm in less than 20 years time. The current y-o-y increase in CO2 is a bit more than 3 ppm. Which indicates to me that we have an acceleration of CO2 levels in the atmosphere to look forward to in the near term (20 years).
If the sinks, mainly ocean and soil, aren't able to absorb carbon as they used to do as you mention in your reply, the increase in atm CO2 might increase even faster.

It seems that in the near term, we will be following the upper extreme scenarios of CC models like the Bern CC or ISAM. It seems we're bound to follow IPCC's scenario RCP8.5 during the coming 20 years due to the 'overhang' from emmisions already made, even if GHG emissions are now eventually starting to decline.

Bruce Steele

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Re: Carbon Cycle
« Reply #326 on: September 26, 2016, 04:38:54 PM »
Hefaistos, I think the 470 ( minimum )is baked in already just as you say. If the 3 ppm +annual is added for twenty more years then  we get 530 , if that is reduced to an annual 2 ppm we  will get 510. There is the chance that the uptick in current annual increases is tied to carbon sinks already beginning to weaken and so if EIA anthropogenic inputs stays flat but annual CO2 increase still increases for another ten years ( averaged )we probably have passed some tipping point. I think everyone is hoping the discrepancy between the purported EIA  flatline figures and the continued atmospheric increases are due to the El Niño and short term sinks quickly releasing part of the 140 .  When the CO2e is added in we may be looking at something closer to 600 for a very disturbing 20 year forecast.
 I would like someone to point out the error in thinking we will have achieved atmospheric doubling in this timeframe but  I think twenty years is about right.  If ASLR is correct and earth climate sensitivity ( ECS ) is higher than most current estimates then most young people alive will see enormous negative effects on the environment  concurrent with spiking temperatures . If the current warm water PDO holds we can expect several more off the charts El Nino events in the next 20 years also. I think we are already seeing negative effects on the oceans here along the West Coast of North America

Edit. I may be double counting the 140 overhang and the 3 ppm annual emissions. The EIA may be undercounting emissions however. Lots of uncertainty
« Last Edit: September 26, 2016, 05:16:33 PM by Bruce Steele »

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Re: Carbon Cycle
« Reply #327 on: September 27, 2016, 05:59:14 PM »
The linked reference indicates that the primary source for the increase in atmospheric methane from 2007 to 2013 was an increase in meteorologically related emissions from tropical wetlands and tropical agriculture:

E. G. Nisbet,et. al. (26 September 2016), "Rising atmospheric methane: 2007-14 growth and isotopic shift", Global Biogeochemical Cycles, DOI: 10.1002/2016GB005406

http://onlinelibrary.wiley.com/doi/10.1002/2016GB005406/full

Abstract: "From 2007 to 2013, the globally-averaged mole fraction of methane in the atmosphere increased by 5.7 ± 1.2 ppb yr-1. Simultaneously, δ13CCH4 (a measure of the 13C/12C isotope ratio in methane) has shifted to significantly more negative values since 2007. Growth was extreme in 2014, at 12.5 ± 0.4 ppb, with a further shift to more negative values being observed at most latitudes. The isotopic evidence presented here suggests the methane rise was dominated by significant increases in biogenic methane emissions, particularly in the tropics: for example, from expansion of tropical wetlands in years with strongly positive rainfall anomalies, or emissions from increased agricultural sources such as ruminants and rice paddies. Changes in the removal rate of methane by the OH radical have not been seen in other tracers of atmospheric chemistry and do not appear to explain short term variations in methane. Fossil fuel emissions may also have grown, but the sustained shift to more 13C-depleted values together with its significant interannual variability, and the tropical and Southern Hemisphere loci of post-2007 growth, both indicate fossil fuel emissions have not been the dominant factor driving the increase. A major cause of increased tropical wetland and tropical agricultural methane emissions, the likely major contributors to growth, may be their responses to meteorological change."
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Re: Carbon Cycle
« Reply #328 on: October 02, 2016, 07:24:18 PM »
In the video of the recent conference in Oxford that discussed keeping below 1.5°C, Professor Corrinne Le Quere says  "Global emissions have stalled in the past few years". Apart from the fact that "stalled" is nowhere good enough, thes reductions are not yet seen in the concentrations of CO2 in the atmosphere. They seem to be accelerating.

These concentrations may be subject to lags or effects such as El Nino but, after allowance for El Nino at least, Tamino writes

Quote
There’s been no deceleration. Whatever emissions reductions have happened, haven’t yet slowed down the rise of CO2.

CO2 concentrations may be subject to lags or effects such as El Nino. Are these the explanations or are carbon feedbacks kicking in (reducing our remaining carbon budget)?
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Re: Carbon Cycle
« Reply #329 on: October 02, 2016, 08:42:31 PM »
CO2 concentrations may be subject to lags or effects such as El Nino. Are these the explanations or are carbon feedbacks kicking in (reducing our remaining carbon budget)?

Obviously, there can be no clear-cut answer to such a question, as who is to say how much un-reported anthropogenic is occurring, in addition to emission sources that AR5/CMIP5-type scientists do not count (such as CO2 from permafrost degradation and methane converted in the atmosphere into CO2).  Nevertheless, fluctuations and un-accounted for anthropogenic emissions aside; I firmly believe that positive feedback mechanisms are currently being accelerated by climate change as discussed in the linked thread entitled: "2015 - The Year of the Feedback".

http://forum.arctic-sea-ice.net/index.php/topic,1419.0.html

 Edit: Here are some specific examples of nature GHG emission sources not included in prior estimates of the "carbon budget":

The first linked article is entitled: "Reservoirs play substantial role in global warming"
http://phys.org/news/2016-09-reservoirs-substantial-role-global.html
Extract: "Washington State University researchers say the world's reservoirs are an underappreciated source of greenhouse gases, producing the equivalent of roughly 1 gigaton of carbon dioxide a year, or 1.3 percent of all greenhouse gases produced by humans."
See also:
https://www.aibs.org/bioscience/

The next linked article is entitled: "Biologist comments on a startling new finding in climate change research":


http://phys.org/news/2016-09-biologist-comments-startling-climate.html

Extract: ""The authors report that the net effect of draining in their study is an increase in the amount of CO2 emitted to the atmosphere, which will ultimately magnify climate change," Zona wrote in her commentary.
Zona published a study about the effects of drainage in permafrost earlier this year in the journal Nature Geoscience. Additionally, she and fellow SDSU ecologist Walt Oechel, along with colleagues at several other institutions, published another study last year showing that the emission of methane, another greenhouse gas, is highest in the Arctic during the region's cold season. That was surprising, as most scientists thought little if any greenhouse gases escaped the frozen soil during the cold season.
Sure enough, Kwon's recent study shows a similar trend for carbon dioxide.
"Importantly, Kwon and colleagues show the increase is highest during the cold season, a notoriously under-studied part of the year in tundra ecosystems," Zona wrote."

See also:

Donatella Zona. Biogeochemistry: Long-term effects of permafrost thaw, Nature (2016). DOI: 10.1038/537625a
Min Jung Kwon et al. Long-term drainage reduces CO2 uptake and increases CO2 emission on a Siberian floodplain due to shifts in vegetation community and soil thermal characteristics, Biogeosciences (2016). DOI: 10.5194/bg-13-4219-2016
&
Anna K. Liljedahl et al. Pan-Arctic ice-wedge degradation in warming permafrost and its influence on tundra hydrology, Nature Geoscience (2016). DOI: 10.1038/ngeo2674

The next linked open access reference indicates that degradation of continuous areas of permafrost (such as in Siberia) currently results in increased local evaporation which in turn promotes local summertime rainfall that promotes snow cover loss, resulting in a current positive feedback for accelerated climate change (global warming).

Trent Ford & Oliver W. Frauenfeld (January 2016), Surface-Atmosphere Moisture Interactions in the Frozen Ground Regions of Eurasia", Scientific Reports, Vol 6, No 19163, doi: 10.1038/srep19163

http://www.nature.com/articles/srep19163

See also:
http://www.newswise.com/articles/future-of-arctic-may-depend-on-permafrost

« Last Edit: October 02, 2016, 08:54:17 PM by AbruptSLR »
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Bruce Steele

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Re: Carbon Cycle
« Reply #330 on: October 03, 2016, 04:51:49 AM »
Geoff, The comments on the Tamino link you posted we're interesting. There is a series of buoys that span the equatorial Pacific called the TAO buoys. ( linked below )  The latest El Niño is the first big El Niño documented by that series of buoys and there are some rather impressive results. The buoys at 110W  and 125W show a slight decrease in surface water pCO2 but the buoys farther east show a marked decrease for the duration of the El Niño . So counter to atmospheric increases documented at Mauna Loa the largest area of ocean to atmosphere ventilation decreased across the Pacific Equatorial Pacific.
 The reason is warm western Pacific water overrides the usual upwelling regions in the Eastern pacific as it is pushed westward and suppresses the upwelling of naturally high pCO2 1000 year old waters.
Now that the El Niño has abated ocean to atmosphere ventilation has resumed with increased vengeance.
 Although the Antarctic Circumpolar current is another region of ocean to atmospheric ventilation we don't have buoys there to watch. I would venture a guess that increased winds and a stronger ACC results in increased ventilation in the Southern Hemisphere but I have no idea how it is affected by the ENSO cycle.
 
http://www.pmel.noaa.gov/co2/story/Open+Ocean+Moorings



AbruptSLR

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Re: Carbon Cycle
« Reply #331 on: October 03, 2016, 05:18:14 AM »
CO2 concentrations may be subject to lags or effects such as El Nino.

El Nino events on average induce drought conditions in most tropical rainforests (see attached image), as the reference looked at about 50-years of data and found "a two-fold increase of carbon cycle sensitivity to tropical temperature variations" primarily due to droughts.


Xuhui Wang, Shilong Piao, Philippe Ciais, Pierre Friedlingstein, Ranga B. Myneni, Peter Cox, Martin Heimann, John Miller, Shushi Peng, Tao Wang, Hui Yang & Anping Chen, (2014), "A two-fold increase of carbon cycle sensitivity to tropical temperature variations", Nature, 506, 212–215, doi:10.1038/nature12915


http://www.nature.com/nature/journal/v506/n7487/full/nature12915.html#extended-data


Abstract: "Earth system models project that the tropical land carbon sink will decrease in size in response to an increase in warming and drought during this century, probably causing a positive climate feedback. But available data are too limited at present to test the predicted changes in the tropical carbon balance in response to climate change. Long-term atmospheric carbon dioxide data provide a global record that integrates the interannual variability of the global carbon balance. Multiple lines of evidence demonstrate that most of this variability originates in the terrestrial biosphere. In particular, the year-to-year variations in the atmospheric carbon dioxide growth rate (CGR) are thought to be the result of fluctuations in the carbon fluxes of tropical land areas. Recently, the response of CGR to tropical climate interannual variability was used to put a constraint on the sensitivity of tropical land carbon to climate change. Here we use the long-term CGR record from Mauna Loa and the South Pole to show that the sensitivity of CGR to tropical temperature interannual variability has increased by a factor of 1.9 ± 0.3 in the past five decades. We find that this sensitivity was greater when tropical land regions experienced drier conditions. This suggests that the sensitivity of CGR to interannual temperature variations is regulated by moisture conditions, even though the direct correlation between CGR and tropical precipitation is weak. We also find that present terrestrial carbon cycle models do not capture the observed enhancement in CGR sensitivity in the past five decades. More realistic model predictions of future carbon cycle and climate feedbacks require a better understanding of the processes driving the response of tropical ecosystems to drought and warming."


The caption for the attached image is (where CGR is "Carbon dioxide Growth Rate):

"CGR anomalies are from Mauna Loa Observatory and local MAT anomalies were derived from the CRU data set for the period 1960–2011. The correlation coefficients 0.23 and 0.28 are the critical thresholds at significance levels of 0.10 and 0.05 (n = 52), respectively."
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Bruce Steele

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Re: Carbon Cycle
« Reply #332 on: October 03, 2016, 05:29:20 AM »
I attach below a long term time series called WHOTS collected from a buoy north of Maui. It shows a marked increase in ocean to atmospheric ventilation for the duration of the El Niño counter to Pacific Equatorial readings. The thing that gives me the willies is the relentless trend line. If the oceans turn to net carbon sources rather than sinks we are truly up the proverbial creek. Atlantic long term readings are similar. See Grey's Reef.



http://www.pmel.noaa.gov/co2/story/WHOTS

AbruptSLR

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Re: Carbon Cycle
« Reply #333 on: October 03, 2016, 03:48:10 PM »
We not should lose track of the current relentless increase in atmospheric methane concentrations & the linked reference indicates net positive methane emissions associated with a thawing boreal forest wetland landscape in North America:

M Helbig, L Chasmer, N Kljun, W L Quinton, C C Treat & O Sonnentag (30 September 2016), "The positive net radiative greenhouse gas forcing of increasing methane emissions from a thawing boreal forest-wetland landscape", Global Change Biology, DOI: 10.1111/gcb.13520

http://onlinelibrary.wiley.com/doi/10.1111/gcb.13520/abstract

Abstract: "At the southern margin of permafrost in North America, climate change causes widespread permafrost thaw. Here, thawing permafrost in forested peat plateaus (“forest”) leads to expansion of permafrost-free wetlands (“wetland”) in boreal lowlands. Expanding wetland area with saturated and warmer organic soils is expected to increase landscape methane (CH4) emissions. Here, we quantify the thaw-induced increase in CH4 emissions for a boreal forest-wetland landscape in the southern Taiga Plains, Canada, and evaluate its impact on net radiative forcing relative to potential long-term net carbon dioxide (CO2) exchange. Using nested wetland and landscape eddy covariance net CH4 flux measurements in combination with flux footprint modeling, we find that landscape CH4 emissions increase with increasing wetland-to-forest ratio. Landscape CH4 emissions are most sensitive to this ratio during peak emission periods, when wetland soils are up to 10 °C warmer than forest soils. The cumulative growing season (May - October) wetland CH4 emissions of ~13 g CH4 m−2 is the dominating contribution to the landscape CH4 emissions of ~7 g CH4 m−2. In contrast, forest contributions to landscape CH4 emissions appear to be negligible. The rapid wetland expansion of 0.26±0.05 % yr−1 in this region causes an estimated growing season increase of 0.034±0.007 g CH4 m−2 yr−1 in landscape CH4 emissions. A long-term net CO2 uptake of > 200 g CO2 m−2 yr−1 is required to offset the positive radiative forcing of increasing CH4 emissions until the end of the 21st century as indicated by an atmospheric CH4 and CO2 concentration model. However, long-term apparent carbon accumulation rates in similar boreal forest-wetland landscapes and landscape eddy covariance net CO2 flux measurements suggest a long-term net CO2 uptake between 49 and 157 g CO2 m−2 yr−1. Thus, thaw-induced CH4 emission increases likely exert a positive net radiative greenhouse gas forcing through the 21st century."
« Last Edit: October 04, 2016, 06:08:27 PM by AbruptSLR »
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AbruptSLR

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Re: Carbon Cycle
« Reply #334 on: October 04, 2016, 06:21:07 PM »
We should also not lose track of the fact that while AR5's RCP scenarios exclude emissions from fires, these fire carbon emissions are currently relentless increasing as indicated by both the first linked reference on trends in fire carbon emissions from Equatorial Asia and its non-linear sensitivity to El Nino (see also the linked Washington Post article) and by the last linked article by Scribbler on Siberian wildfires, and the exhaustion of man's discretionary resources to effectly fight such events:

Yi Yin, Philippe Ciais, Frederic Chevallier, Guido R. van der Werf, Thierry Fanin, Gregoire Broquet, Hartmut Boesch, Anne Cozic, Didier Hauglustaine, Sophie Szopa & Yilong Wang (23 September 2016), "Variability of fire carbon emissions in Equatorial Asia and its non-linear sensitivity to El Niño", Geophysical Research Letters; DOI: 10.1002/2016GL070971

http://onlinelibrary.wiley.com/doi/10.1002/2016GL070971/full

Abstract: "The large peatland carbon stocks in the land use change-affected areas of Equatorial Asia are vulnerable to fire. Combining satellite observations of active fire, burned area, and atmospheric concentrations of combustion tracers with a Bayesian inversion, we estimated the amount and variability of fire carbon emissions in Equatorial Asia over the period 1997-2015. Emissions in 2015 were of 0.51 ± 0.17 Pg carbon – less than half of the emissions from the previous 1997 extreme El Niño, explained by a less acute water deficit. Fire severity could be empirically hindcasted from the cumulative water deficit with a lead time of 1 to 2 months. Based on future climate projections and an exponential empirical relationship found between fire carbon emissions and water deficit, we infer a total fire carbon loss ranging from 12 to 25 Pg by 2100 in the coming decades, a significant positive feedback to future climate warming."

Also see:
https://www.washingtonpost.com/news/energy-environment/wp/2016/10/03/there-are-our-carbon-emissions-and-then-there-are-the-ones-the-earth-will-punish-us-with/?utm_term=.cd9f34ec5e21

Extract: "In the new study in Geophysical Research Letters, a team of researchers led by Yi Yin of the French Laboratoire des Sciences du Climat et de l’Environnement look at the potential of peat bogs in equatorial Asia — a region that includes Malaysia, Papua New Guinea and several other smaller countries but is dominated by Indonesia and its largest islands, Borneo and Sumatra — to worsen our climate problems. It’s timely, considering that last year amid El Niño-induced drought conditions Indonesian blazes emitted over 1.5 billion tons of carbon dioxide equivalents into the atmosphere. That’s more than the annual emissions of Japan (or, needless to say, of Indonesia’s fossil fuel burning).

The study finds a tight relationship between El Niño events and large peat fire emissions over the past 19 years. And it projects that under a high global emissions scenario, a warming climate will trigger more intense El Niños that, in turn, will correspond to more intense blazes (barring, that is, some major policy or political change that stops humans from starting fires to begin with). And under more moderate warming, there could still be major peat fire emissions during the century, the research finds.
“Most climate models predict a little bit stronger, not more El Niños, but more intense El Niños,” says Guido van der Werf, one of the study’s co-authors and a fire emissions researcher at VU University in Amsterdam.
And so much carbon could be lost in this way that it could affect the global atmosphere in what the paper calls a “significant positive feedback to global warming.”
More specifically, the study forecasts that as many as 25 petagrams, or billion tons, of carbon could be released in a high warming scenario — and 13 billion tons in a more modest warming scenario, which would require significantly changing the globe’s emissions trajectory and shifting it downward, while still likely missing the goal of limiting warming to just 2 degrees Celsius above pre-industrial levels.
If these numbers are converted to carbon dioxide, which has a larger molecular weight, that would correspond to between more than 47 billion tons in the more moderate warming scenario and about 91 billion tons of carbon dioxide for the high emissions scenario. (In fires, most of the greenhouse gas emissions would be in the form of carbon dioxide, though there would also be some methane and nitrous oxide emitted.)
The carbon math is clear: The world simply can’t have such an additional source of emissions. For instance, the so-called “carbon budget” for holding warming below 2 degrees Celsius above pre-industrial levels was about 1,000 billion tons of carbon dioxide, as of 2011. And that’s for human burning of fossil fuels — not for releases from peat fires. If these fire emissions happen, then the already extremely narrow carbon budget becomes even narrower.

The research suggests that, along with worrying about all the carbon stored in Arctic permafrost, which could greatly add to emissions in this century, we definitely have to worry about the carbon in peat, too.
“There’s definitely more carbon stored in boreal regions, but it’s not as vulnerable as this stuff,” van der Werf says. “If you get another few El Niño, you get a big pulse. Permafrost is a much more gradual process.”"

See also the following Scribbler article entitled: "“We are Suffocating from Smoke” — For Russia, Climate Change is Already Producing Fires that are Too Big to Fight".

https://robertscribbler.com/2016/09/28/for-one-month-we-are-suffocating-from-smoke-for-russia-climate-change-is-already-producing-fires-that-are-too-big-to-fight/

Extract: "Exhaustion of emergency response resources is one of the big threats posed by climate change. In instances where entire regions see extreme weather conditions that are far outside the norm for an extended period of time, such as as severe droughts, floods, and fires, instances of exhaustion are more likely to occur. Exhaustion also occurs when events appear that are too large or intense to manage. It appears that firefighting efforts in Russia are starting to show some signs of exhaustion. Not good, especially considering the fact that these conditions are tame compared to what will happen in future years without some very serious climate change mitigation and response efforts now."
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AbruptSLR

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Re: Carbon Cycle
« Reply #335 on: October 04, 2016, 10:07:36 PM »
The linked reference studies terrestrial permafrost cores from Siberia regarding the nature of the associated organic matter (OM) and concludes: "Considering the expected increase of permafrost thaw due to climate warming, this implies a potentially strong impact on greenhouse gas generation from permafrost areas in future with positive feedback on climate variation." 

Apparently, the OM is well suit for supporting microorganism that can generate methane that has 35 times the GWP of carbon dioxide:

J. G. Stapel, L. Schirrmeister, P. P. Overduin, S. Wetterich, J. Strauss, B. Horsfield &K. Mangelsdorf (30 September 2016), "Microbial lipid signatures and substrate potential of organic matter in permafrost deposits - implications for future greenhouse gas production", Biogeosciences, DOI: 10.1002/2016JG003483


http://onlinelibrary.wiley.com/doi/10.1002/2016JG003483/abstract

Abstract: "A terrestrial permafrost core from Buor Khaya in northern Siberia comprising deposits of Late Pleistocene to Early Holocene age has been investigated to characterize living and past microbial communities with respect to modern and paleoclimate environmental conditions, and to evaluate the potential of the organic matter (OM) for greenhouse gas generation. Microbial life markers - intact phospholipids and phospholipid fatty acids - are found throughout the entire core and indicate the presence of living microorganisms also in older permafrost deposits. Biomarkers for past microbial communities (branched and isoprenoid GDGT as well as archaeol) reveal links between increased past microbial activity and intervals of high OM accumulation accompanied by increased OM quality presumably caused by local periods of moister and warmer environmental conditions. Concentrations of acetate as an excellent substrate for methanogenesis are used to assess the OM quality with respect to microbial degradability for greenhouse gas production. For this purpose two acetate pools are determined: the pore-water acetate and OM bound acetate. Both depth profiles reveal similarities to the OM content and quality indicating a link between the amount of the stored OM and the potential to provide substrates for microbial greenhouse gas production. The data suggest that OM stored in the permafrost deposits is not much different in terms of OM quality than the fresh surface organic material. Considering the expected increase of permafrost thaw due to climate warming, this implies a potentially strong impact on greenhouse gas generation from permafrost areas in future with positive feedback on climate variation."
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Re: Carbon Cycle
« Reply #336 on: October 06, 2016, 05:33:15 AM »
Phosphorus feedbacks will likely constrain the response of tropical ecosystems to future increases in atmospheric CO2 levels; thus limiting the ability of this sink to absorb future CO2 emissions:

Xiaojuan Yang, et. al.,(2016), "Phosphorus Feedbacks Constraining Tropical Ecosystem Responses to Changes in Atmospheric CO2 and Climate.", Geophysical Research Letters, [doi: 10.1002/2016GL069241].


http://onlinelibrary.wiley.com/doi/10.1002/2016GL069241/abstract



Abstract: “The effects of phosphorus (P) availability on carbon (C) cycling in the Amazon region are investigated using CLM-CNP. We demonstrate that the coupling of P dynamics reduces the simulated historical terrestrial C sink due to increasing atmospheric CO2 concentrations ([CO2]) by about 26%. Our exploratory simulations show that the response of tropical forest C cycling to increasing [CO2] depends on how elevated CO2 affects phosphatase enzyme production. The effects of warming are more complex, depending on the interactions between humidity, C, and nutrient dynamics. While a simulation with low humidity generally shows the reduction of net primary productivity (NPP), a second simulation with higher humidity suggests overall increases in NPP due to the dominant effects of reduced water stress and more nutrient availability. Our simulations point to the need for (1) new observations on how elevated [CO2] affects phosphatase enzyme production and (2) more tropical leaf-scale measurements under different temperature/humidity conditions with different soil P availability. “
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Re: Carbon Cycle
« Reply #337 on: October 13, 2016, 05:05:34 PM »
The two linked reference study pan-Arctic methane emissions and global lake methane emissions, respectively.  Taken together with discussion of the total global methane emissions, these reference help to clarify the complicated story of the multiple sources of the currently accelerating global methane emissions:

Tan, Z., Zhuang, Q., Henze, D. K., Frankenberg, C., Dlugokencky, E., Sweeney, C., Turner, A. J., Sasakawa, M., and Machida, T.: Inverse modeling of pan-Arctic methane emissions at high spatial resolution: what can we learn from assimilating satellite retrievals and using different process-based wetland and lake biogeochemical models?, Atmos. Chem. Phys., 16, 12649-12666, doi:10.5194/acp-16-12649-2016, 2016.

http://www.atmos-chem-phys.net/16/12649/2016/

Abstract. Understanding methane emissions from the Arctic, a fast-warming carbon reservoir, is important for projecting future changes in the global methane cycle. Here we optimized methane emissions from north of 60° N (pan-Arctic) regions using a nested-grid high-resolution inverse model that assimilates both high-precision surface measurements and column-average SCanning Imaging Absorption spectroMeter for Atmospheric CHartogrphY (SCIAMACHY) satellite retrievals of methane mole fraction. For the first time, methane emissions from lakes were integrated into an atmospheric transport and inversion estimate, together with prior wetland emissions estimated with six biogeochemical models. In our estimates, in 2005, global methane emissions were in the range of 496.4–511.5 Tg yr−1, and pan-Arctic methane emissions were in the range of 11.9–28.5 Tg yr−1. Methane emissions from pan-Arctic wetlands and lakes were 5.5–14.2 and 2.4–14.2 Tg yr−1, respectively. Methane emissions from Siberian wetlands and lakes are the largest and also have the largest uncertainty. Our results indicate that the uncertainty introduced by different wetland models could be much larger than the uncertainty of each inversion. We also show that assimilating satellite retrievals can reduce the uncertainty of the nested-grid inversions. The significance of lake emissions cannot be identified across the pan-Arctic by high-resolution inversions, but it is possible to identify high lake emissions from some specific regions. In contrast to global inversions, high-resolution nested-grid inversions perform better in estimating near-surface methane concentrations.

&

Jorge Encinas Fernández, Frank Peeters & Hilmar Hofmann (12 October 2016), "On the methane paradox: Transport from shallow-water zones rather than in situ methanogenesis is the mayor source of CH4 in the open surface water of lakes", JGR Biogeosciences, DOI: 10.1002/2016JG003586

http://onlinelibrary.wiley.com/doi/10.1002/2016JG003586/abstract

Abstract: "Estimates of global methane (CH4) emissions from lakes and the contributions of different pathways are currently under debate. In situ methanogenesis linked to algae growth was recently suggested to be the major source of CH4 fluxes from aquatic systems. However, based on our very large dataset on CH4 distributions within lakes, we demonstrate here that methane-enriched water from shallow-water zones is the most likely source of the basin-wide mean CH4 concentrations in the surface water of lakes. Consistently, the mean surface CH4 concentrations are significantly correlated with the ratio between the surface area of the shallow-water zone and the entire lake, fA,s/t, but not with the total surface area. The categorization of CH4 fluxes according to fA,s/t may therefore improve global estimates of CH4 emissions from lakes. Furthermore, CH4 concentrations increase substantially with water temperature, indicating that seasonally resolved data are required to accurately estimate annual CH4 emissions."
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Re: Carbon Cycle
« Reply #338 on: October 27, 2016, 07:06:00 PM »
ASLR posted an article on the Hansen 3+ meter sea rise by 2100 page that has a link to this open sourced paper relevant to the carbon cycle.


http://geology.gsapubs.org/content/early/2016/10/20/G38636.1.full.pdf

The paper is a study on core samples taken from an area in the North Atlantic from sea bottom dominated by ADW. In the core samples the sediments reflect changes between the deep water sources of North Atlantic origin or Southern Ocean origin.  When the Southern Ocean water dominates it's high pCO2 levels lead to corrosive conditions that result in dissolution of bottom sediments that increase alkalinity. Once upwelled these waters then can absorb more atmospheric CO2 and promote glaciation.  The last part of the article is a nice summary.
 Do to the long time required for water transport at these depths( and then back to the surface ) I wouldn't expect changes to be relevant at  anything less than multiple century to thousand year timeframes.

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Re: Carbon Cycle
« Reply #339 on: November 08, 2016, 11:07:39 PM »
The linked reference & associated following linked article indicate that from 2002 to 2014 there was a temporary pause in the rate of atmosphere carbon dioxide growth rate (down to around 2ppm per year, see the attached image) associated with an increase in terrestrial carbon uptake.  While that is nice, it appears that the pause is temporary in nature as from October 2015 to October 2016 atmospheric carbon dioxide at Mauna Loa increased by 3.28ppm.  Furthermore, Hansen has warned that carbon temporarily sequestered in terrestrial organic material is subject to future release with continued global warming

Keenan et. al. (2016) "Recent pause in the growth rate of atmospheric CO₂ due to enhanced terrestrial carbon uptake", Nature Communication, doi:10.1038/ncomms13428.

http://www.nature.com/articles/ncomms13428

See also the associated article entitled: "Rise in atmospheric CO2 slowed by green vegetation"

http://www.bbc.com/news/science-environment-37909361

Extract: "The growth in the amount of CO2 in the Earth's atmosphere has been slowed by the increased ability of plants to soak up the gas.

"We have a huge amount of vegetation on the Earth and that was being fertilised by CO2 and taking in more CO2 as a result."
Another important element in the story is the impact of a hiatus in global temperature increases on the behaviour of plants. Between 1998 and 2012 temperatures went up by less than in previous decades. This has impacted the respiration of vegetation.
"The soils and ecosystem are respiring so as temperatures increase they respire more, releasing more CO2 into the atmosphere," said Dr Keenan.
"In the past decade or so there hasn't been much of an increase in global temperatures, so that meant there wasn't much of an increase in respiration and carbon release so that was fundamentally different in the past decade or so compared to previous periods."
One consequence of a warming world that has been expected to increase was the number of droughts around the world. However, this new study suggests that, on a global scale, there has been little or no change in the prevalence of drought over recent decades.
Overall though the slowdown caused by vegetation hasn't stemmed the total rise of carbon which has now passed the symbolically important level of 400 parts per million (ppm) in the atmosphere."

Edit:

See also the following linked article entitled: "How scientists predicted CO2 would breach 400ppm in 2016"

https://www.carbonbrief.org/how-scientists-predicted-co2-would-breach-400pm-2016

Extract: "If the world’s nations are serious about halting global warming, the rise in CO2 concentrations also needs to cease. This means the annual change in CO2 concentration – generally 2ppm per year, and around 3ppm this year – needs to become zero. That is, the sinks need to balance the sources. Based on our current understanding of the carbon cycle, this task will be harder the longer we leave it."
« Last Edit: November 08, 2016, 11:12:53 PM by AbruptSLR »
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Re: Carbon Cycle
« Reply #340 on: November 21, 2016, 06:43:39 PM »
The linked reference identifies a source of marine methane emissions that was not previously recognized.  I am concerned that as the ocean's surface water temperature increases these methane emissions from bacterial activity will increase:

Daniel J. Repeta, Sara Ferrón, Oscar A. Sosa, Carl G. Johnson, Lucas D. Repeta, Marianne Acker, Edward F. DeLong & David M. Karl (2016), "Marine methane paradox explained by bacterial degradation of dissolved organic matter", Nature Geoscience, doi:10.1038/ngeo2837


http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo2837.html


Abstract: "Biogenic methane is widely thought to be a product of archaeal methanogenesis, an anaerobic process that is inhibited or outcompeted by the presence of oxygen and sulfate. Yet a large fraction of marine methane delivered to the atmosphere is produced in high-sulfate, fully oxygenated surface waters that have methane concentrations above atmospheric equilibrium values, an unexplained phenomenon referred to as the marine methane paradox. Here we use nuclear magnetic resonance spectroscopy to show that polysaccharide esters of three phosphonic acids are important constituents of dissolved organic matter in seawater from the North Pacific. In seawater and pure culture incubations, bacterial degradation of these dissolved organic matter phosphonates in the presence of oxygen releases methane, ethylene and propylene gas. Moreover, we found that in mutants of a methane-producing marine bacterium, Pseudomonas stutzeri, disrupted in the C–P lyase phosphonate degradation pathway, methanogenesis was also disabled, indicating that the C–P lyase pathway can catalyse methane production from marine dissolved organic matter. Finally, the carbon stable isotope ratio of methane emitted during our incubations agrees well with anomalous isotopic characteristics of seawater methane. We estimate that daily cycling of only about 0.25% of the organic matter phosphonate inventory would support the entire atmospheric methane flux at our study site. We conclude that aerobic bacterial degradation of phosphonate esters in dissolved organic matter may explain the marine methane paradox."
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Re: Carbon Cycle
« Reply #341 on: November 21, 2016, 07:03:43 PM »
The linked reference indicates that ocean acidification could drive a cascading loss of biodiversity in some marine habitats.


Jennifer M. Sunday, Katharina E. Fabricius, Kristy J. Kroeker, Kathryn M. Anderson, Norah E. Brown, James P. Barry, Sean D. Connell, Sam Dupont, Brian Gaylord, Jason M. Hall-Spencer, Terrie Klinger, Marco Milazzo, Philip L. Munday, Bayden D. Russell, Eric Sanford, Vengatesen Thiyagarajan, Megan L. H. Vaughan, Stephen Widdicombe & Christopher D. G. Harley (2016), "Ocean acidification can mediate biodiversity shifts by changing biogenic habitat", Nature Climate Change, doi:10.1038/nclimate3161


http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate3161.html

Abstract: "The effects of ocean acidification (OA) on the structure and complexity of coastal marine biogenic habitat have been broadly overlooked. Here we explore how declining pH and carbonate saturation may affect the structural complexity of four major biogenic habitats. Our analyses predict that indirect effects driven by OA on habitat-forming organisms could lead to lower species diversity in coral reefs, mussel beds and some macroalgal habitats, but increases in seagrass and other macroalgal habitats. Available in situ data support the prediction of decreased biodiversity in coral reefs, but not the prediction of seagrass bed gains. Thus, OA-driven habitat loss may exacerbate the direct negative effects of OA on coastal biodiversity; however, we lack evidence of the predicted biodiversity increase in systems where habitat-forming species could benefit from acidification. Overall, a combination of direct effects and community-mediated indirect effects will drive changes in the extent and structural complexity of biogenic habitat, which will have important ecosystem effects."
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Re: Carbon Cycle
« Reply #342 on: November 24, 2016, 08:59:15 PM »
"The analysis shows that concentrations of human-caused CO2 are greatest in shallow waters where the atmosphere gives up large amounts of its CO2 to the sea. The researchers also estimated that CO2 concentrations from fossil fuel emissions make up as much as 60 percent of the CO2 that enriches most West Coast nearshore surface waters. But the concentrations dropped as they measured deeper. It drops to 21 percent in deeper waters of 328 feet or 100 meters, and falls even lower to about 18 percent in waters below 656 feet or 200 meters. Concentrations vary depending on location and seasons as well.
 
Once researchers created a detailed map of the human-generated CO2 concentrations, they  looked at how pteropod shells fared in areas with varying seawater CO2 concentrations. They found more than 50 percent of pteropod shells collected from coastal waters with the high CO2 concentrations were severely dissolved. An estimated 10 to 35 percent of pteropods taken from offshore waters showed shell damage when examined under a scanning electron microscope."


http://www.noaa.gov/media-release/noaa-research-links-human-caused-co2-emissions-to-dissolving-sea-snail-shells-off-us


So anthropogenic CO2 in nearshore waters where it is the most concentrated results in severe shell dissolution in 50% of the pteropods sampled.  These rates of dissolution will both expand in range and severity over the next several decades even if we do somehow manage to reduce emissions...
The shape of things to come.
« Last Edit: November 24, 2016, 09:08:26 PM by Bruce Steele »

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Re: Carbon Cycle
« Reply #343 on: November 27, 2016, 11:55:13 PM »
The linked article is entitled: "The Big Blue Elephant in the Room"; and it points out that most current climate policy discussion inappropriately downplay the importance of the health of the ocean to sustaining the type of life on Earth that people are adapted to:

https://medium.com/@yearsoflivingdangerously/the-big-blue-elephant-in-the-room-29d1a0c5f423#.n9zqv3ip7

Extract: "… we know: the living ocean governs planetary chemistry; regulates temperature; generates most of the oxygen in the sea and atmosphere; powers the water, carbon, and nitrogen cycles; and holds 97 percent of Earth’s water and 97 percent of the biosphere. Quite simply, no ocean, no life. No blue, no green. If not for the ocean, there would be no climate to discuss or anyone around to debate the issues."
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Re: Carbon Cycle
« Reply #344 on: November 28, 2016, 06:38:41 AM »
Once again I would like to point out that the claims about 90% of the worlds bony fishes having disappeared is erroneous . Sylvia Earle should know better but I guess religion is more persuasive than fact checking her sources. The Worm et al 2003 paper that made the original claim was followed by Worm and Hilborn 2009 that revises the claims made earlier.
 At any rate closing fishing without addressing terrestrial emissions is scapegoating and if you look at the Calif. fishing reserves as an example existing oil drilling and extraction is exempted from regulation in the reserve designation process. There are zero fish stocks on the entire North Pacific coastline Mexico to Alaska that have been reduced to < 10% of virgin biomass by fishing. A couple abalone stocks might be so reduced but that  is  due to disease and abalone is closed to take.
 I have been far more involved in the reserve process here in Calif. than Sylvia Earl , we have about 25-30 % of all fishing grounds in state waters closed.  How those closures impact the carbon cycle is pure speculation but we closed the fishing grounds more with goal of risk aversion than somehow averting some impending disaster. The Carbon Cycle played no part in the discussions although I did try to raise the issue.
 Anyway I get tired of taking a beating by hit pieces like the one Abrupt posted and I will continue to try to support reasonable fish management that results in sustainable fisheries where and when i can make a difference. If the religiously inclined environmentalists would give credit to reasonable management where it occurs it would go a long way to encouraging similar efforts at risk averse fishery management in other parts of the world .
 Here is a review of the Worm /Hilborn  debate and resulting co-authored paper


https://theteteatete.org/2014/12/03/case-study-the-hilborn-worm-debate-on-the-status-of-global-fisheries/





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Re: Carbon Cycle
« Reply #345 on: November 28, 2016, 06:38:12 PM »
The linked reference & associated following linked article indicate that from 2002 to 2014 there was a temporary pause in the rate of atmosphere carbon dioxide growth rate (down to around 2ppm per year, see the attached image) associated with an increase in terrestrial carbon uptake.  While that is nice, it appears that the pause is temporary in nature as from October 2015 to October 2016 atmospheric carbon dioxide at Mauna Loa increased by 3.28ppm.  Furthermore, Hansen has warned that carbon temporarily sequestered in terrestrial organic material is subject to future release with continued global warming

Keenan et. al. (2016) "Recent pause in the growth rate of atmospheric CO₂ due to enhanced terrestrial carbon uptake", Nature Communication, doi:10.1038/ncomms13428.

http://www.nature.com/articles/ncomms13428

See also the associated article entitled: "Rise in atmospheric CO2 slowed by green vegetation"

http://www.bbc.com/news/science-environment-37909361

Extract: "The growth in the amount of CO2 in the Earth's atmosphere has been slowed by the increased ability of plants to soak up the gas.

"We have a huge amount of vegetation on the Earth and that was being fertilised by CO2 and taking in more CO2 as a result."
Another important element in the story is the impact of a hiatus in global temperature increases on the behaviour of plants. Between 1998 and 2012 temperatures went up by less than in previous decades. This has impacted the respiration of vegetation.
"The soils and ecosystem are respiring so as temperatures increase they respire more, releasing more CO2 into the atmosphere," said Dr Keenan.
"In the past decade or so there hasn't been much of an increase in global temperatures, so that meant there wasn't much of an increase in respiration and carbon release so that was fundamentally different in the past decade or so compared to previous periods."
One consequence of a warming world that has been expected to increase was the number of droughts around the world. However, this new study suggests that, on a global scale, there has been little or no change in the prevalence of drought over recent decades.
Overall though the slowdown caused by vegetation hasn't stemmed the total rise of carbon which has now passed the symbolically important level of 400 parts per million (ppm) in the atmosphere."

Edit:

See also the following linked article entitled: "How scientists predicted CO2 would breach 400ppm in 2016"

https://www.carbonbrief.org/how-scientists-predicted-co2-would-breach-400pm-2016

Extract: "If the world’s nations are serious about halting global warming, the rise in CO2 concentrations also needs to cease. This means the annual change in CO2 concentration – generally 2ppm per year, and around 3ppm this year – needs to become zero. That is, the sinks need to balance the sources. Based on our current understanding of the carbon cycle, this task will be harder the longer we leave it."

Tamino strongly refuted this in a great post (he's a stats guy):

https://tamino.wordpress.com/2016/11/11/another-pause-claim/

Doesn't look like a pause to me either. Looking pretty silly after the last two years of data showing 3 and (likely) 3.5 ppm of rise. Some of that is due to ENSO, but given how large those numbers are, it certainly doesn't fall in with a pause theory.
« Last Edit: November 28, 2016, 06:52:48 PM by Csnavywx »

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Re: Carbon Cycle
« Reply #346 on: November 28, 2016, 07:16:52 PM »

Tamino strongly refuted this in a great post (he's a stats guy):

https://tamino.wordpress.com/2016/11/11/another-pause-claim/

Doesn't look like a pause to me either. Looking pretty silly after the last two years of data showing 3 and (likely) 3.5 ppm of rise. Some of that is due to ENSO, but given how large those numbers are, it certainly doesn't fall in with a pause theory.

As Gavin Schmidt likes to point-out, attribution without a fully calibrated advanced Earth System Model is impossible.  So no matter how sincere Tamino's statists may be, they cannot rule-out the probability that terrestrial plants may be temporarily soaking-up more carbon dioxide than they were a few decades ago.  If so things could become much worse for us all once our currently unprecedented rate of climate change starts to overstress both the terrestrial and oceanic plants.
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Re: Carbon Cycle
« Reply #347 on: November 29, 2016, 03:53:09 AM »

Tamino strongly refuted this in a great post (he's a stats guy):

https://tamino.wordpress.com/2016/11/11/another-pause-claim/

Doesn't look like a pause to me either. Looking pretty silly after the last two years of data showing 3 and (likely) 3.5 ppm of rise. Some of that is due to ENSO, but given how large those numbers are, it certainly doesn't fall in with a pause theory.

As Gavin Schmidt likes to point-out, attribution without a fully calibrated advanced Earth System Model is impossible.  So no matter how sincere Tamino's statists may be, they cannot rule-out the probability that terrestrial plants may be temporarily soaking-up more carbon dioxide than they were a few decades ago.  If so things could become much worse for us all once our currently unprecedented rate of climate change starts to overstress both the terrestrial and oceanic plants.

It's possible, but there's no direct evidence for it. I think that was the point of Tamino's article. It was perplexing to see a 12-year trend being used in a peer-reviewed paper, especially since we regularly lambast deniers for using such short intervals for spurious claims about global temperature trends. There's not even any evidence for a slowdown in the rate of acceleration.

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Re: Carbon Cycle
« Reply #348 on: November 29, 2016, 06:09:49 AM »
The linked article discusses how the impacts of ocean acidification may be more widespread and may last longer (multiple centuries) than most people think:

http://www.latimes.com/science/sciencenow/la-sci-sn-phytoplankton-acidic-oceans-20160708-snap-story.html

Speaking of acidification -- the latest episode of Years of Living Dangerously (s2) is called "Collapse of the Oceans" and is a particularly bone crushing episode that deals with this issue. Ove's experimental test plots with future temps and pH were alarmingly bad.

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Re: Carbon Cycle
« Reply #349 on: November 29, 2016, 12:43:07 PM »
Csnavywx, Acidification is the issue that brought me into the climate change discussion ~ ten years ago when the OA field was very young. I consider myself a very well informed amateur. If you go back to the beginning of the carbon cycle page ( three years ago ) I tried to link some relevant articles.
  I wish the effects of acidification were only going to last " hundreds of years "  like the LA Times article suggests but they are off by thousands or tens of thousands of years. Everything depends on when we actually stop emitting CO2 and to what degree feedbacks of carbon stored in sinks are released  due to the carbon excursion we are precipitating.
 So the physics of acidification are fairly straight forward and the duration of an acidification event can be reasonable well constrained ( although the carbon feedbacks are still a bit of a mystery ). Anyhow just the effects of releasing the proven carbon reserves  will result in thousands of years of acidification,not hundreds. ( see  Caldeira and Wicket 2003 ) below.


http://faculty.wwu.edu/~shulld/ESCI%20432/Caldeira_and_Wickett_2003.pdf

We have already released ~ 600 Gt carbon and are releasing > 10 Gt carbon per year . We will most certainly hit 1000 Gt and acidification will proceed whether we take 50 or 500 years to do so. Caldeira's 5000 Gt release results in a -.7 pH change in the world surface waters in a couple hundred years. So pH 8.3 preindustrial becomes pH 7.6 and results in under saturation of all the worlds surface waters.
If there is a large release of carbon from carbon sinks ( and there will be ) that results from the heating and stress to terrestrial carbon sinks the resultant ocean pH will be even lower.   This is a classic trigger for a very large extinction event in the worlds oceans. If this should occur it would take millions of years for the oceans diversity to reestablish.