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S.Pansa

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Re: Conservative Scientists & its Consequences
« Reply #1650 on: March 07, 2017, 08:46:39 AM »
It seems difficult to determine what scientists have done with regards to modeling permafrost carbon emissions in CMIP5.  However, to me the linked reference seems to indicate that CMIP5 used land models that did not represent carbon emissions from permafrost very well (and thus they have low confidence in the projected emissions); and that scientists will try to do a better job in CMIP6. ...

That's my impression as well. Here is another very nice paper that comes pretty much to the same conclusion.
Schuur etal (including Schaefer, McGuire, ...), Climate change and the permafrost carbon feedback, Nature 2015 (doi:10.1038/nature14338, free copy here).
The paper is based on research that was published after AR5.  On page 177 it says:

Quote
Next steps for model–data integration
The Earth system models analysed for the IPCC AR5 did not include permafrost carbon emissions, and there is a need for the next assessment to make substantive progress analyzing this climate feedback. It is clear, even among models that are currently capable of simulating permafrost carbon emissions, that improvements are needed to the simulations of the physical and biological processes that control the dynamics of permafrost distribution and soil
thermal regime.

More on the shortfalls of the current permafrost carbon models (same page).

The bad news are outlined on page 176:
Quote
There is uncertainty, but the vulnerable fraction does not appear to be twice as high or half as much as 5%–15%, based on this analysis. Ten per cent of the known terrestrial permafrost carbon pool is equivalent to, 130–160 Pg carbon.

If my math is correct, that equates to 475 to 590 Gt CO2 to the end of this century. The only good news: According to them, most of it will be released constantly in form of CO2-carbon. An abrupt release is not likely, they conclude:

Quote
projected emissions of CO2 and CH4 from thawing permafrost are unlikely to occur at a speed that could cause abrupt climate change over a period of a few years to a decade

The sad thing is. Pretty much all of the carbon budget estimates and mitigation pathways (at least those I am aware of) are base on the AR5-framework. Consequently, most of them do ignore the emissions from permafrost carbon feedback. 
Taking into account that the best estimate for these emissions is 475 to 590 Gt CO2 (until 2100), most of these budget-estimates and pathways are imho based in an alternative reality, or in  la la land (with a lot of arctic sea ice left in the summers after 2050?). What is the best guess for the 2C-carbon budget 1.000 Gt CO2?
Of course this is not news to you guys ... but it gets constantly ignored elsewhere. And even than most of the 2C-pathways require absurd amounts of negative emissions. What a mess ...

/rant ;)

Ah, all will be fine. Let's simple built a billion E-SUVs, just under 2 tones each - those who enable us to finally enjoy our wonderful nature & stop - en passant - the ongoing mass extinction (needs a cool app of course)

AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #1651 on: March 07, 2017, 04:57:42 PM »
The linked article is entitled: "Global greening may soak up less carbon dioxide than projected", and it makes it clear that scientists have ESLD again.

https://www.newscientist.com/article/2123610-global-greening-may-soak-up-less-carbon-dioxide-than-projected/?utm_campaign=Echobox&utm_medium=Social&utm_source=Twitter#link_time=1488883052

Extract: "Our planet is getting greener thanks in part to the growth-boosting effects of extra carbon dioxide in the air. But this greening won’t soak up quite as much carbon dioxide from the atmosphere as climate scientists have been projecting.

That’s the conclusion of the first experiment to test the effect of raised CO2 levels on trees growing in soil low in phosphorus, which is common in the tropics and subtropics."

See also:
Journal reference: Nature Climate Change, DOI: 10.1038/NCLIMATE3235
Journal reference: Nature Ecology & Evolution, DOI: 10.1038/s41559-017-0081
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DrTskoul

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Re: Conservative Scientists & its Consequences
« Reply #1652 on: March 07, 2017, 07:20:04 PM »
EsLD ?

AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #1653 on: March 08, 2017, 02:30:08 AM »
EsLD ?

Erred on the Side of Least Drama.
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DrTskoul

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Re: Conservative Scientists & its Consequences
« Reply #1654 on: March 08, 2017, 03:10:44 AM »
Ahhh ...Thanks.

jai mitchell

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Re: Conservative Scientists & its Consequences
« Reply #1655 on: March 08, 2017, 06:10:50 PM »
Quote
The sad thing is. Pretty much all of the carbon budget estimates and mitigation pathways (at least those I am aware of) are base on the AR5-framework
(edited by jai)

Yep, but that is not all of the scientific knowledge that was disallowed in the AR5 CMIP5 model runs there are many more. for instance:

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gerontocrat

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Re: Conservative Scientists & its Consequences
« Reply #1656 on: March 08, 2017, 06:57:01 PM »
Quote
The sad thing is. Pretty much all of the carbon budget estimates and mitigation pathways (at least those I am aware of) are base on the AR5-framework
(edited by jai)

Yep, but that is not all of the scientific knowledge that was disallowed in the AR5 CMIP5 model runs there are many more. for instance:

Just looked at schedule for AR6. 3 working group reports in 2021, synthesis report 2022, Final UNFCCC report 2023. So physical observations after 2020 can't get in?
What chance of getting missing feedbacks in ?

Will the horse have not only left the stable but also the stable burnt down ?  This observer believes that by 2023 the Arctic will be a different place.



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AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #1657 on: March 08, 2017, 07:22:54 PM »
Just looked at schedule for AR6. 3 working group reports in 2021, synthesis report 2022, Final UNFCCC report 2023. So physical observations after 2020 can't get in?
What chance of getting missing feedbacks in ?

Will the horse have not only left the stable but also the stable burnt down ?  This observer believes that by 2023 the Arctic will be a different place.
I have previously posted a lot of information about the efforts to better calibrate AR6 in the "Climate Model Test Beds: Calibrating Nonlinear ESMs" at the link below (be sure to look at both pages of the thread):

http://forum.arctic-sea-ice.net/index.php/topic,1478.50.html
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AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #1658 on: March 09, 2017, 10:24:23 PM »
Quote
The sad thing is. Pretty much all of the carbon budget estimates and mitigation pathways (at least those I am aware of) are base on the AR5-framework
(edited by jai)

Yep, but that is not all of the scientific knowledge that was disallowed in the AR5 CMIP5 model runs there are many more. for instance:

No policy maker would accept any projection without a CMIP6 level of effort; however, the computers in the CMIP6 project to not have enough power to correctly model the interaction of all feedbacks (I believe that ACME has the world's more powerful computers used for climate modeling and I do not believe that its Phase I projections will be included in CMIP6).  In addition to jai's list of underestimated feedbacks, there are indications that cloud feedbacks are more positive than previously assumed, and I do not believe that any CMIP6 model accounts for Hansen's ice-climate interaction.  Thus, more than likely we will be able to measure real climate responses sooner than we will get reasonably accurate climate model projections.
“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: Conservative Scientists & its Consequences
« Reply #1659 on: March 10, 2017, 02:58:20 AM »
Quote
The sad thing is. Pretty much all of the carbon budget estimates and mitigation pathways (at least those I am aware of) are base on the AR5-framework
(edited by jai)

Yep, but that is not all of the scientific knowledge that was disallowed in the AR5 CMIP5 model runs there are many more. for instance:
No policy maker would accept any projection without a CMIP6 level of effort; however, the computers in the CMIP6 project to not have enough power to correctly model the interaction of all feedbacks (I believe that ACME has the world's more powerful computers used for climate modeling and I do not believe that its Phase I projections will be included in CMIP6).  In addition to jai's list of underestimated feedbacks, there are indications that cloud feedbacks are more positive than previously assumed, and I do not believe that any CMIP6 model accounts for Hansen's ice-climate interaction.  Thus, more than likely we will be able to measure real climate responses sooner than we will get reasonably accurate climate model projections.


Just looked at schedule for AR6. 3 working group reports in 2021, synthesis report 2022, Final UNFCCC report 2023. So physical observations after 2020 can't get in?
What chance of getting missing feedbacks in ?

Will the horse have not only left the stable but also the stable burnt down ?  This observer believes that by 2023 the Arctic will be a different place.

well on the upside that will give them plenty of time to:

  • realize how incredibly off their models were WRT Sea ice loss, ENSO response/warming response/Global Atmospheric circulation response to SO2 emissions reductions in China
  • go through the painstaking process of lead author and contributing author selection for the "Mea Culpa to Humanity and the World from the Global Scientific Community" that will serve as the prologue to the executive summary of the AR6
   





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nicibiene

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Re: Conservative Scientists & its Consequences
« Reply #1660 on: March 10, 2017, 11:30:18 AM »
Just read a little about the obviously in the models included hopefully presumption more CO2 means more biomass growth and the chance for more food (as a lot of people mean).

https://www.scientificamerican.com/article/as-carbon-dioxide-grows-tropical-trees-do-not/

"Computer models that predict how climate change will play out assume that as greenhouse gas concentrations go up, forests will take advantage of the additional carbon dioxide and grow a bit more, increasing their capacity to mitigate global warming...."

I found pretty interesting details about the photosyntesis of C3 and C4 plants, I wasn't aware by now. C3 (most are that type) plants adapted to a lower athmospheric CO2 level, they need to breath more air to get their energy, their photosynthesis is not that efficient. The problem is, for more gas exchange they have to open their stomata longer. With open stomata they loose watervapour, they need enough water for growth, they are hurtable when drought an heat appears. More athmospheric CO2 would first mean, they have to breath less, shut their stomata longer. You could mean, so they could deal better with drought, but less evaporation means a loss of the cooling effect for their leaves. The leaves loose their air condition and get dry. Not a real good thing for more growth as the leaves are their engine  :o ...

https://academic.oup.com/treephys/article-lookup/doi/10.1093/treephys/tpr002#25185304

As scientists looked for the growth of tree rings in the tropics-where water sets no limits, they found that there is no effect of more growth. They assume that more starch, sugar could be transported to the ground/roots or soil minerals/nutricious borders set limits. Why should trees grow more then the soil gives them? I think they have a root powered sense for what is good for them, a balance system. They simply shut their stomata, they hold their breath somehow, to survive. Just like an starving animal stops moving to keep the energy balanced. But what will be, if the heat increases? Will they use the water to cool down? The behaviour of the northern trees seems to tell, they will not. I think they have no choice. Breathing means metabolism.

And what would it mean if water & CO2 overfed tropical trees hold their breath? Maybe that could also cause the little negative feedback of more athmospheric water vapour, atmospheric rivers, or tropical wetlands?

https://www.scientificamerican.com/article/as-carbon-dioxide-grows-tropical-trees-do-not/

Also very big source discussing the question - with a lot of other cross references seems to be that:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4865672/#!po=2.00000
(maybe I will dig through it, but not now)

Also remarkable: Wheat e.g.seem to get less nutricious.

http://science.sciencemag.org/content/328/5980/899
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jai mitchell

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Re: Conservative Scientists & its Consequences
« Reply #1661 on: March 10, 2017, 06:05:24 PM »
http://fusion.net/story/391091/soil-study-portends-major-carbon-release/

Deep soil carbon much more active in response to warming that previously thought

Quote
The implications of this study, the first to extensively look at carbon stocks in soil below 20 centimeters in depth—which contain more than 50% of the planet’s soil-based organic carbon—are extremely worrisome, according to the study:

    The results shed light on what is potentially a big source of uncertainty in climate projections. Soil organic carbon harbors three times as much carbon as Earth’s atmosphere. In addition, warming is expected to increase the rate at which microbes break down soil organic carbon, releasing more CO2 into the atmosphere and contributing to climate change.

Quote
“Our calculations suggest that by 2100 the warming of deeper soil layers could cause a release of carbon to the atmosphere at a rate that is significantly higher than today, perhaps even as high as 30% of today’s human-caused annual carbon emissions depending on the assumptions on which the estimate is based,” said Caitlin Hicks Pries, a postdoctoral researcher in Berkeley Lab’s Climate and Ecosystem Sciences Division.

study here:  http://science.sciencemag.org/content/early/2017/03/08/science.aal1319

http://newscenter.lbl.gov/2017/03/09/soils-carbon-climate/
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Andre

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Re: Conservative Scientists & its Consequences
« Reply #1662 on: March 10, 2017, 09:26:54 PM »
Improved estimates of ocean heat content from 1960 to 2015

http://advances.sciencemag.org/content/3/3/e1601545.full

Abstract:
We found that changes in OHC are relatively small before about 1980; since then, OHC has increased fairly steadily and, since 1990, has increasingly involved deeper layers of the ocean. In addition, OHC changes in six major oceans are reliable on decadal time scales. All ocean basins examined have experienced significant warming since 1998, with the greatest warming in the southern oceans, the tropical/subtropical Pacific Ocean, and the tropical/subtropical Atlantic Ocean. This new look at OHC and EEI changes over time provides greater confidence than previously possible, and the data sets produced are a valuable resource for further study.


One of the co-authors of the study also wrote a piece for the Guardian:

Earth's oceans are warming 13% faster than thought, and accelerating

https://www.theguardian.com/environment/climate-consensus-97-per-cent/2017/mar/10/earths-oceans-are-warming-13-faster-than-thought-and-accelerating

Abstract:
First, we corrected past data for known biases in measurements. Second, we related the temperature measurements to results calculated from advanced climate computer models. Third, we applied temperature knowledge to larger areas so that a single measurement was representative of a large space around the measurement site. Finally, we used their knowledge of recent and well-observed temperatures to show that the method produced excellent results.

We were able to extend our techniques back to the late1950s and show that the rate of global warming has changed significantly in the past 60 years. One main outcome of the study is that it shows we are warming about 13% faster than we previously thought. Not only that but the warming has accelerated. The warming rate from 1992 is almost twice as great as the warming rate from 1960. Moreover, it is only since about 1990 that the warming has penetrated to depths below about 700 meters.






« Last Edit: March 10, 2017, 09:39:25 PM by Andre »

AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #1663 on: March 10, 2017, 10:34:54 PM »
The linked Scribbler article is entitled: "New Research Shows Global Warming Could Turn Tropics Into a Sweltering Dead Zone".  I note that if climate sensitivity is worse than that assumed by these studies, then we may well see much worse damage by the end of the century, than what such articles project.

https://robertscribbler.com/2017/03/09/new-research-shows-global-warming-could-turn-tropics-into-a-sweltering-dead-zone/

Extract: "New research out of Purdue University finds that a global warming event called the PETM made parts of the tropics too hot for living organisms to survive. And though the PETM happened many millions of years ago, these new scientific revelations are pertinent to the present day. The reason is that human activity in the form of fossil fuel burning is now rapidly causing the globe to heat up. And such warming, if it continues, could well turn large sections of the tropics into a dead zone.

During the present day, about half the human population, a good chunk of the world’s life forms, and a considerable amount of global farming occupies the tropics. However, according to recent research by the Max Planck Institute, parts of the tropical zone could be rendered basically uninhabitable to human beings by mid Century as the Earth heats up due to fossil fuel burning."

See also the associated following linked article entitled: "Evidence disproving tropical ‘thermostat’ theory: global warming can breach limits for life"

https://www.purdue.edu/newsroom/releases/2017/Q1/evidence-disproving-tropical-thermostat-theory-global-warming-can-breach-limits-for-life.html

Extract: "New research findings show that as the world warmed millions of years ago, conditions in the tropics may have made it so hot some organisms couldn’t survive.

Longstanding theories dating to the 1980s suggest that as the rest of the earth warms, the tropical temperatures would be strictly limited, or regulated by an internal ‘thermostat.’"

&

The following linked article entitled: "Climate-exodus expected in the Middle East and North Africa".

https://www.mpg.de/10481936/climate-change-middle-east-north-africa

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AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #1664 on: March 11, 2017, 06:07:57 PM »
One main outcome of the study is that it shows we are warming about 13% faster than we previously thought. Not only that but the warming has accelerated. The warming rate from 1992 is almost twice as great as the warming rate from 1960. Moreover, it is only since about 1990 that the warming has penetrated to depths below about 700 meters.

Andre,

Thanks for this important reference; as it confirms that climate sensitivity is higher than AR5 assumes.

Also, for those who like reference citations I provide the following:

Lijing Cheng, Kevin E. Trenberth, John Fasullo, Tim Boyer, John Abraham and Jiang Zhu (10 Mar 2017), "Improved estimates of ocean heat content from 1960 to 2015", Science Advances, Vol. 3, no. 3, e1601545, DOI: 10.1126/sciadv.1601545
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #1665 on: March 11, 2017, 07:12:42 PM »
    • go through the painstaking process of lead author and contributing author selection for the "Mea Culpa to Humanity and the World from the Global Scientific Community" that will serve as the prologue to the executive summary of the AR6
       



    "At the advent of danger there are always two voices that speak with equal force in the human heart: one very reasonably invites a man to consider the nature of the peril and the means of escaping it; the other, with a still greater show of reason, argues that it is too depressing and painful to think of the danger since it is not in man's power to foresee everything and avert the general march of events, and it is better therefore to shut one's eyes to the disagreeable until it actually comes, and to think instead of what is pleasant. When a man is alone he generally listens to the first voice; in the company of his fellow-men, to the second."
    - Tolstoy, War and Peace.

    I doubt that AR6 will include any Mea Culpa from scientists, so long as they can hide in the company of do-nothing policy makers, a self-serving public and Pollyannaish magic-thinkers.
    [/list]
    « Last Edit: March 12, 2017, 12:41:18 AM by AbruptSLR »
    “It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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    AbruptSLR

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    Re: Conservative Scientists & its Consequences
    « Reply #1666 on: March 12, 2017, 05:09:08 PM »
    http://fusion.net/story/391091/soil-study-portends-major-carbon-release/

    Deep soil carbon much more active in response to warming that previously thought

    Quote
    The implications of this study, the first to extensively look at carbon stocks in soil below 20 centimeters in depth—which contain more than 50% of the planet’s soil-based organic carbon—are extremely worrisome, according to the study:

        The results shed light on what is potentially a big source of uncertainty in climate projections. Soil organic carbon harbors three times as much carbon as Earth’s atmosphere. In addition, warming is expected to increase the rate at which microbes break down soil organic carbon, releasing more CO2 into the atmosphere and contributing to climate change.

    Quote
    “Our calculations suggest that by 2100 the warming of deeper soil layers could cause a release of carbon to the atmosphere at a rate that is significantly higher than today, perhaps even as high as 30% of today’s human-caused annual carbon emissions depending on the assumptions on which the estimate is based,” said Caitlin Hicks Pries, a postdoctoral researcher in Berkeley Lab’s Climate and Ecosystem Sciences Division.

    study here:  http://science.sciencemag.org/content/early/2017/03/08/science.aal1319

    http://newscenter.lbl.gov/2017/03/09/soils-carbon-climate/

    This research seems important enough to merit a more complete citation, as it indicates that carbon emissions from deeper soils are more sensitive to warming than previously assumed:

    Caitlin E. Hicks Pries, C. Castanha, R. Porras & M. S. Torn (09 Mar 2017), "The whole-soil carbon flux in response to warming", Science, DOI: 10.1126/science.aal1319

    http://science.sciencemag.org/content/early/2017/03/08/science.aal1319

    Extract: "Soil organic carbon harbors three times as much carbon as Earth’s atmosphere, and its decomposition is a potentially large climate change feedback and major source of uncertainty in climate projections. The response of whole-soil profiles to warming has not been tested in situ. In this deep warming experiment in mineral soil, CO2 production from all soil depths increased significantly with 4°C warming—annual soil respiration increased by 34-37%. All depths responded to warming with similar temperature sensitivities, driven by decomposition of decadal-aged carbon. Whole-soil warming reveals a larger soil respiration response than many in situ experiments, most of which only warm the surface soil, and models."

    See also the linked article entitled: "Study: Soils Could Release Much More Carbon Than Expected as Climate Warms"

    http://newscenter.lbl.gov/2017/03/09/soils-carbon-climate/

    Extract: "Their findings are based on a field experiment that, for the first time, explored what happens to organic carbon trapped in soil when all soil layers are warmed, which in this case extend to a depth of 100 centimeters. The scientists discovered that warming both the surface and deeper soil layers at three experimental plots increased the plots’ annual release of CO2 by 34 to 37 percent over non-warmed soil. Much of the CO2 originated from deeper layers, indicating that deeper stores of carbon are more sensitive to warming than previously thought."
    “It is not the strongest or the most intelligent who will survive but those who can best manage change.”
    ― Leon C. Megginson

    AbruptSLR

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    Re: Conservative Scientists & its Consequences
    « Reply #1667 on: March 12, 2017, 05:29:46 PM »
    Andre,

    Thanks for this important reference; as it confirms that climate sensitivity is higher than AR5 assumes.

    Also, for those who like reference citations I provide the following:

    Lijing Cheng, Kevin E. Trenberth, John Fasullo, Tim Boyer, John Abraham and Jiang Zhu (10 Mar 2017), "Improved estimates of ocean heat content from 1960 to 2015", Science Advances, Vol. 3, no. 3, e1601545, DOI: 10.1126/sciadv.1601545

    Not to seem repetitive, but it is a big deal that the oceans are warming 13% faster than previously assumed as discussed by Scribbler in the linked article entitled: "The Oceans are Warming Faster than Previously Thought; Rate of Heat Build-up Accelerating"

    https://robertscribbler.com/2017/03/10/the-oceans-are-warming-faster-than-previously-though-rate-of-heat-build-up-is-accelerating/

    Extract: "This increased rate of warming is rather concerning — especially when you consider the fact that about 90 percent of the total extra heat absorbed by carbon dioxide and other greenhouse gasses produced primarily by fossil fuel burning ends up in the world’s oceans. For this reason, ocean heat gain is probably a better determiner of overall global warming than atmospheric heat gain. And, as a result, what we’re looking at is a world that’s surprising us with the rate at which it is responding to the insults of human fossil fuel emissions.

    Of course, heat in the oceans produces numerous added impacts to the Earth System. As we’ve seen in Antarctica and Greenland, that heat gain has caused a number of the world’s largest ice shelves and glaciers to start melting from below — increasing concerns about the future rate of global sea level rise. The accelerating heat gain in the world’s oceans is absolutely the primary driver of the ongoing global coral bleaching event that has continued uninterrupted since 2014. More ocean heat means less oxygen — which increases the extent of ocean dead zones. And various sea creatures from starfish to mollusks to walruses to puffins have all seen habitat loss and/or loss of key food sources due to ongoing warming.

    Extra ocean heat also both reduces the ability of the ocean to absorb CO2 even as it puts stress on various carbon stores — increasing the risk that a carbon feedback response from the Earth System will emerge to further worsen the rate of global warming.

    Finally, warmer oceans can help to push hydrological events such as instances of heavy rainfall and severe drought to greater extremes.  A press release by the study’s authors noted:

    "…we know the oceans are much warmer now and they contain the memory of climate change. Higher sea surface temperatures are continually reinforced by the extra heat beneath the ocean surface. The oceans are affecting weather and climate through more intense rains. This process is a major reason why 2016 was the hottest year ever recorded at the Earth’s surface, beating out 2015 which was the previous record. Additionally 2015 was a year with record hurricanes, heat waves, droughts, and wild-fires around the world.""
    “It is not the strongest or the most intelligent who will survive but those who can best manage change.”
    ― Leon C. Megginson

    DrTskoul

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    Re: Conservative Scientists & its Consequences
    « Reply #1668 on: March 12, 2017, 06:57:57 PM »
    Atmospheric temperatures are kept in check by the ocean, if the ocean starts warming faster it is going to get bumpy

    AbruptSLR

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    Re: Conservative Scientists & its Consequences
    « Reply #1669 on: March 15, 2017, 10:37:27 PM »
    The linked article is entitled: "The feedback paradox"; and it indicates that high natural variability likely indicates high climate sensitivity.

    https://andthentheresphysics.wordpress.com/2017/03/14/the-feedback-paradox/

    Extract: "What’s quite often been discussed/mentioned here is that if one argues for a significant natural contribution to our long-term warming, then that’s potentially arguing for a high climate sensitivity.

    Any feedback process based on temperature will act on both natural and forced changes in the temperature. If such feedbacks result in pronounced natural temperature variations, they also imply that the climate sensitivity is high."
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    nicibiene

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    Re: Conservative Scientists & its Consequences
    « Reply #1670 on: March 16, 2017, 09:00:40 AM »
    As I thought a little about the effects of deeper thawing of permafrost, more decomposition and the warming effect of that processes, combined with the fact that siberia gets more snow than before. Here a nice article about a team of scientists that went out to have a look at that effects.

    http://www.sciencepoles.org/interview/what-is-happening-to-carbon-in-arctic-tundra-permafrost

    Quote
    Our experiment was unusual in that it was intended to be a summer warming experiment only, but it turned into a summer and winter warming experiment in the end. Researchers who have done winter warming experiments see that there is much stronger decomposition going on during winter compared to summer. The reason for this is that when the soils are just below freezing, even relatively small increases in temperature strongly stimulates decomposers into action.



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    GeoffBeacon

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    Re: Conservative Scientists & its Consequences
    « Reply #1671 on: March 16, 2017, 02:58:59 PM »
    I rely on Carbon Brief's excellent daily information but, unusually, one of my comments didn't get through moderation.  It was in Humans causing up to two-thirds of Arctic summer sea ice loss. This was concerning the paper by Ding et. al. that some of the media used to claim that only half the sea ice loss was due to human activity.

    I'm not sure whether it was just CB's spam filter or I said something I shouldn't. I certainly don't put them in the "conservative scientists" camp. Was my comment really out of order and was it reasonably accurate?

    Quote

    Jai

    Thanks for telling me this study is based on the CMIP5 ensemble. This should have given it a health warning.  Just before the Department of Energy and Climate Change was shut down, their climate experts told me ...

    Quote
    In answer to your specific questions:

    1. Am I correct in thinking that some of these feedbacks were not used in the models that calculated the “remaining carbon budgets” – as used in the IPCC AR5?

    Quote
    That’s correct, the models used vary in what they include, and some feedbacks are absent as the understanding and modelling of these is not yet advanced enough to include. From those you raise, this applies to melting permafrost emissions, forest fires and wetlands decomposition.

    2. Are there other missing feedbacks that should be considered?
    Quote
    The feedbacks you mention are certainly important, although there are several other feedbacks that could be included, but are currently too difficult to model. As knowledge and understanding advances, they will be added to the climate models.

    See Carbon budgets: A straightforward answer from DECC

    I have a dispute with Nature over subscriptions so I'm not paying to read this article but my guess is that it should be titled "The CMIP5 ensemble can only explain half the Arctic sea ice loss."

    Did Ding et al. know they were using faulty tools?
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    jai mitchell

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    Re: Conservative Scientists & its Consequences
    « Reply #1672 on: March 16, 2017, 03:24:57 PM »
    Quote
    Did Ding et al. know they were using faulty tools?

    of course they did but they gave it an attribution regardless.
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    Re: Conservative Scientists & its Consequences
    « Reply #1673 on: March 21, 2017, 06:18:03 PM »
    The linked reference indicates that models indicate that rainfall will increase rapidly in the Arctic in coming years.  This should increase Arctic Amplification to higher levels than previously assumed in AR5 (if for no other reason than that rain will markedly increase methane emissions from Arctic permafrost).

    R. Bintanja et al. Towards a rain-dominated Arctic, Nature Climate Change (2017). DOI: 10.1038/nclimate3240

    http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate3240.html

    Abstract
    Climate models project a strong increase in Arctic precipitation over the coming century, which has been attributed primarily to enhanced surface evaporation associated with sea-ice retreat. Since the Arctic is still quite cold, especially in winter, it is often (implicitly) assumed that the additional precipitation will fall mostly as snow. However, little is known about future changes in the distributions of rainfall and snowfall in the Arctic. Here we use 37 state-of-the-art climate models in standardized twenty-first-century (2006–2100) simulations to show a decrease in average annual Arctic snowfall (70°–90° N), despite the strong precipitation increase. Rain is projected to become the dominant form of precipitation in the Arctic region (2091–2100), as atmospheric warming causes a greater fraction of snowfall to melt before it reaches the surface, in particular over the North Atlantic and the Barents Sea. The reduction in Arctic snowfall is most pronounced during summer and autumn when temperatures are close to the melting point, but also winter rainfall is found to intensify considerably. Projected (seasonal) trends in rainfall and snowfall will heavily impact Arctic hydrology (for example, river discharge, permafrost melt), climatology (for example, snow, sea-ice albedo and melt)8, 9 and ecology (for example, water and food availability).
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    AbruptSLR

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    Re: Conservative Scientists & its Consequences
    « Reply #1674 on: March 23, 2017, 06:17:53 PM »
    The linked article is entitled: "New Video: It's Alive – Microbes and Melt on the Greenland Ice Sheet"; and I recommend watching the associated video as it discusses and important positive feedback mechanism for both global warming and for sea level rise that was not included in AR5 projections (but which Jason Box has warned about for many years).

    https://www.skepticalscience.com/microbes-melt-gis.html

    Extract: "In recent years, several research groups have been looking in detail at the darkening of the ice sheet – and understanding that, as the planet warms, and ice melts, more liquid water means more habitat for bugs, more darkening, more melt,..you get the picture."
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    AbruptSLR

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    Re: Conservative Scientists & its Consequences
    « Reply #1675 on: March 26, 2017, 08:52:34 AM »
    The linked Scribbler article is entitled: " From Canada to Siberia, Permafrost Thaw Produces ‘Hell’s Mouth’ Craters, Sinking Lands, and 7,000 Methane Pockets Waiting to Blow", and it notes that the AR5 projections do not adequately account for these sources of GHG this century:

    https://robertscribbler.com/2017/03/24/from-canada-to-siberia-permafrost-thaw-produces-hells-mouth-craters-sinking-lands-and-7000-methane-pockets-waiting-to-blow/
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    AbruptSLR

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    Re: Conservative Scientists & its Consequences
    « Reply #1676 on: March 27, 2017, 11:33:58 PM »
    The linked article is entitled: "Extreme weather events linked to climate change impact on the jet stream", which indicates that climate changes to the jet stream are increasing extreme weather events.  The level of sensitivity of this behavior to radiative forcing was not identified in AR5.

    https://www.sciencedaily.com/releases/2017/03/170327083120.htm

    Summary: "Unprecedented summer warmth and flooding, forest fires, drought and torrential rain -- extreme weather events are occurring more and more often, but now an international team of climate scientists has found a connection between many extreme weather events and the impact climate change is having on the jet stream."

    See the associate reference at:

    Michael E. Mann, Stefan Rahmstorf, Kai Kornhuber, Byron A. Steinman, Sonya K. Miller, Dim Coumou. Influence of Anthropogenic Climate Change on Planetary Wave Resonance and Extreme Weather Events. Scientific Reports, 2017; 7: 45242 DOI: 10.1038/srep45242

    http://www.nature.com/articles/srep45242

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    AbruptSLR

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    Re: Conservative Scientists & its Consequences
    « Reply #1677 on: March 31, 2017, 08:03:34 PM »
    The linked reference indicates that forests play a more important role in keeping the planet cool than was previously appreciated.  Thus if one assumes that they are entitled to make self-serving assumptions one could assume that decision makers will not only preserve forests but will expand them in the future.  However, the reality is that we are currently losing forests at a rate appropriate for a BAU scenario; and which could accelerate in the future.  Thus if we keep losing forest, our AR5 projections may err on the side of least drama:

    Ryan M. Bright et al. Local temperature response to land cover and management change driven by non-radiative processes, Nature Climate Change (2017). DOI: 10.1038/nclimate3250


    http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate3250.html

    Abstract: "Following a land cover and land management change (LCMC), local surface temperature responds to both a change in available energy and a change in the way energy is redistributed by various non-radiative mechanisms. However, the extent to which non-radiative mechanisms contribute to the local direct temperature response for different types of LCMC across the world remains uncertain. Here, we combine extensive records of remote sensing and in situ observation to show that non-radiative mechanisms dominate the local response in most regions for eight of nine common LCMC perturbations. We find that forest cover gains lead to an annual cooling in all regions south of the upper conterminous United States, northern Europe, and Siberia—reinforcing the attractiveness of re-/afforestation as a local mitigation and adaptation measure in these regions. Our results affirm the importance of accounting for non-radiative mechanisms when evaluating local land-based mitigation or adaptation policies."
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    AbruptSLR

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    Re: Conservative Scientists & its Consequences
    « Reply #1678 on: April 01, 2017, 05:45:07 PM »
    The linked article is entitled: "Climate change: global reshuffle of wildlife will have huge impacts on humanity".  While scientists are indeed warning us of this threat, when they err on the side of least drama with regard to GMSTA projections, by extension they also err on the side of least drama with regard to the threat to humanity posed by global warming's impacts on threats like changing ranges for pests and stress on the ecosystem.

    https://www.theguardian.com/environment/2017/mar/30/climate-change-global-reshuffle-of-wildlife-will-have-huge-impacts-on-humanity

    Extract: "Mass migration of species to cooler climes has profound implications for society, pushing disease-carrying insects, crop pests and crucial pollinators into new areas, says international team of scientists."
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    AbruptSLR

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    Re: Conservative Scientists & its Consequences
    « Reply #1679 on: April 02, 2017, 08:33:48 PM »
    The linked article is entitled: “Melting glaciers around Mount Everest may be forming killer lakes”.  The associated reference (see the second link) concludes that: “Our results suggest that glacial lake expansion across the Himalayas could expedite ice mass loss and the prediction of future contributions of glacial meltwater to river flow will be complicated by spatially variable glacier responses to climate change.”

    I am putting this post in this thread, instead of the thread on glaciers, because denialists attacked AR4 for stating that significant ice mass loss from Himalayan glaciers could occur in decades rather than centuries; which is one of the many reasons that AR5 errs so far on the side of least drama.  Now this, and other (see the third link), research indicates that meltwater hydraulic systems (lakes, drainage systems etc.) are actively accelerating ice mass loss from these mountain glaciers (which is largely masked from gravity monitoring systems like the GRACE satellites).  Thus it is increasingly probably that significant ice mass loss will occur from Himalayan glaciers in the decade timescale; indicating that AR5 never should have been dumbed-down as much as it was; and hopefully AR6 will correct that situation:

    http://www.sciencemag.org/news/2017/02/melting-glaciers-around-mount-everest-may-be-forming-killer-lakes

    Extract: “Of the roughly 198,000 glaciers on the planet, more than a quarter are found in the Himalayas. But even this frigid expanse of ice and snow—home to nine of the world’s 10 highest peaks—is reeling from climate change. Many Himalayan glaciers are receding—and a new study of 32 glaciers around Mount Everest has found that those terminating in lakes have lost more ice mass than landlocked glaciers. That’s a worrying trend because many glacial lakes form behind unstable debris dams that are poised to collapse and send disastrous floods hurtling down valleys.
    Himalayan glaciers are losing ice mass because of decreased snowfall and higher average air temperatures that melt existing ice. “The landscape is primed for lake development,” says Owen King, a glaciologist at the University of Leeds in the United Kingdom, who led the study.”
    See the associated reference:

    King, O., Quincey, D. J., Carrivick, J. L., and Rowan, A. V.: Spatial variability in mass loss of glaciers in the Everest region, central Himalayas, between 2000 and 2015, The Cryosphere, 11, 407-426, doi:10.5194/tc-11-407-2017, 2017.

    http://www.the-cryosphere.net/11/407/2017/

    Abstract. Region-wide averaging of Himalayan glacier mass change has masked any catchment or glacier-scale variability in glacier recession; thus the role of a number of glaciological processes in glacier wastage remains poorly understood. In this study, we quantify mass loss rates over the period 2000–2015 for 32 glaciers across the Everest region and assess how future ice loss is likely to differ depending on glacier hypsometry. The mean mass balance of all 32 glaciers in our sample was −0.52 ± 0.22 m water equivalent (w.e.) a−1. The mean mass balance of nine lacustrine-terminating glaciers (−0.70 ± 0.26 m w.e. a−1) was 32 % more negative than land-terminating, debris-covered glaciers (−0.53 ± 0.21 m w.e. a−1). The mass balance of lacustrine-terminating glaciers is highly variable (−0.45 ± 0.13 to −0.91 ± 0.22 m w.e. a−1), perhaps reflecting glacial lakes at different stages of development. To assess the importance of hypsometry on glacier response to future temperature increases, we calculated current (Dudh Koshi – 0.41, Tama Koshi – 0.43, Pumqu – 0.37) and prospective future glacier accumulation area Ratios (AARs). IPCC AR5 RCP 4.5 warming (0.9–2.3 °C by 2100) could reduce AARs to 0.29 or 0.08 in the Tama Koshi catchment, 0.27 or 0.17 in the Dudh Koshi catchment and 0.29 or 0.18 in the Pumqu catchment. Our results suggest that glacial lake expansion across the Himalayas could expedite ice mass loss and the prediction of future contributions of glacial meltwater to river flow will be complicated by spatially variable glacier responses to climate change.


    See also:

    Benn, D. I., Thompson, S., Gulley, J., Mertes, J., Luckman, A., and Nicholson, L.: Structure and evolution of the drainage system of a Himalayan debris-covered glacier, and its relationship with patterns of mass loss, The Cryosphere Discuss., doi:10.5194/tc-2017-29, in review, 2017.

    http://www.the-cryosphere-discuss.net/tc-2017-29/

    Abstract. This paper provides the first synoptic view of the drainage system of a Himalayan debris-covered glacier and its evolution through time, based on speleological exploration and satellite image analysis of Ngozumpa Glacier, Nepal. The drainage system has several linked components: 1) a seasonal subglacial drainage system below the upper ablation zone; 2) supraglacial channels allowing efficient meltwater transport across parts of the upper ablation zone; 3) sub-marginal channels, allowing long-distance transport of meltwater; 4) perched lakes, which intermittently store meltwater prior to evacuation via the englacial drainage system; 5) englacial cut-and-closure conduits, which may undergo repeated cycles of abandonment and reactivation; 6) a 'base-level' lake system (Spillway Lake) dammed behind the terminal moraine. The distribution and relative importance of these elements has evolved through time, in response to sustained negative mass balance. The area occupied by perched lakes has expanded upglacier at the expense of supraglacial channels, and Spillway Lake has grown as more of the glacier surface ablates to base level. Subsurface processes play a governing role in creating, maintaining and shutting down exposures of ice at the glacier surface, with a major impact on spatial patterns and rates of surface mass loss. Comparison of our results with observations on other glaciers indicate that englacial drainage systems play a key role in the response of debris-covered glaciers to sustained periods of negative mass balance.
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    AbruptSLR

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    Re: Conservative Scientists & its Consequences
    « Reply #1680 on: April 04, 2017, 12:58:55 AM »
    The linked research indicates that as the Arctic Sea Ice becomes thinner, portions of the ice become thin enough to allow sufficient light to pass through the ice to support phytoplankton blooms beneath the zones of think ice.  This trend is increasing faster than previously assumed and it is decreasing the albedo of the affected ice zones; which is a positive feedback mechanism that was not adequately accounted for in AR5.

    Christopher Horvat, David Rees Jones, Sarah Iams, David Schroeder, Daniela Flocco and Daniel Feltham (2017), "The frequency and extent of sub-ice phytoplankton blooms in the Arctic Ocean", Science Advances, Vol. 3, no. 3, e1601191, DOI: 10.1126/sciadv.1601191

    http://advances.sciencemag.org/content/3/3/e1601191

    Abstract: "In July 2011, the observation of a massive phytoplankton bloom underneath a sea ice–covered region of the Chukchi Sea shifted the scientific consensus that regions of the Arctic Ocean covered by sea ice were inhospitable to photosynthetic life. Although the impact of widespread phytoplankton blooms under sea ice on Arctic Ocean ecology and carbon fixation is potentially marked, the prevalence of these events in the modern Arctic and in the recent past is, to date, unknown. We investigate the timing, frequency, and evolution of these events over the past 30 years. Although sea ice strongly attenuates solar radiation, it has thinned significantly over the past 30 years. The thinner summertime Arctic sea ice is increasingly covered in melt ponds, which permit more light penetration than bare or snow-covered ice. Our model results indicate that the recent thinning of Arctic sea ice is the main cause of a marked increase in the prevalence of light conditions conducive to sub-ice blooms. We find that as little as 20 years ago, the conditions required for sub-ice blooms may have been uncommon, but their frequency has increased to the point that nearly 30% of the ice-covered Arctic Ocean in July permits sub-ice blooms. Recent climate change may have markedly altered the ecology of the Arctic Ocean."

    Also see the linked article entitled: "What's Behind the Arctic's Mysterious Green Ice?"

    http://www.livescience.com/58492-arctic-green-ice-explained.html

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    AbruptSLR

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    Re: Conservative Scientists & its Consequences
    « Reply #1681 on: April 10, 2017, 04:34:46 PM »
    The linked article is entitled: "How frozen farmers’ fields are an unexpected culprit in climate change, according to a new study".  Scientists have previously underestimated the nitrous oxide emissions from thawing frozen croplands.

    http://news.nationalpost.com/news/canada/how-frozen-farmers-fields-are-an-unexpected-culprit-in-climate-change-according-to-a-new-study

    Extract: "Across Canada, the last of the snow and ice is melting away from a vast expanse of farmers’ fields, making way for the planting of this year’s crops.

    And — suggests a new Canadian study — making an unexpectedly large contribution to greenhouse gases and climate change.

    Strange as it might seem, the thawing of frozen cropland burps nitrous oxide into the atmosphere at rates far greater than previously thought, meaning agriculture’s role in producing the greenhouse gas has been greatly underestimated, according to University of Guelph research.

    Nitrous oxide — commonly known as laughing gas and used as a dental anesthetic — accounts for well under 10 per cent of greenhouse gas emissions. But it’s almost 300 times as potent as carbon dioxide at trapping energy, the greenhouse effect believed to be warming the planet."
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    AbruptSLR

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    Re: Conservative Scientists & its Consequences
    « Reply #1682 on: April 12, 2017, 12:29:45 AM »
    The linked open access reference provide information that older permafrost (particularly from MIS 3 and MIS 4) have a high potential to generate more methane, as they thaw, than previously assumed:

    Janina G. Stapel et. al. (2017), "Substrate potential of Eemian to Holocene permafrost organic matter for future microbial greenhouse gas production", Biogeosciences Discuss., doi:10.5194/bg-2017-89

    http://www.biogeosciences-discuss.net/bg-2017-89/bg-2017-89.pdf

    Abstract. Multiple permafrost cores from Bol´shoy Lyakhovsky Island in NE Siberia comprising deposits from Eemian to modern time are investigated to evaluate the stored potential of the freeze-locked organic matter (OM) to serve as substrate for the production of microbial greenhouse gases from thawing permafrost deposits. Deposits from Late Pleistocene glacial periods (comprising MIS 3 and MIS 4) possess an increased aliphatic character and a higher amount of potential substrates, and therefore higher OM quality in terms of biodegradation compared to interglacial deposits from the Eemian (MIS 5e) as well as from the Holocene (MIS 1). To assess the potential of the individual permafrost deposits to provide substrates for microbially induced greenhouse gas generation, concentrations of free and bound acetate as an excellent substrate for methanogenesis are used. The highest free (in pore water and segregated ice) and bound (bound to the organic matrix) acetate-substrate pools of the permafrost deposits are observed within the interstadial MIS 3 and stadial MIS 4 period deposits. In contrast, deposits from the last interglacial MIS 5e show only poor substrate pools. The Holocene deposits reveal a significant bound-acetate pool, representing at least a future substrate potential upon release during OM degradation.  Biomarkers for past microbial communities (branched and isoprenoid GDGTs) show also highest abundance of past microbial communities during the MIS 3 and MIS 4 deposits, which indicates higher OM quality with respect to microbial degradation during time of deposition. On a broader perspective, Arctic warming will increase permafrost thaw and favour substrate availability from freeze-locked older permafrost deposits. Therefore, especially those deposits from MIS 3 and MIS 4 show a high potential for providing substrates relevant for methanogenesis.

    Edit: Per the extracted information from the linked Wikipedia article on Marine Isotope Stage; it is likely that in many zones of the global permafrost regions that the MIS 3 & 4 permafrost layers are located relatively near the surface:

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

    Extract:
    "•   MIS 1 - 14 kya, end of the Younger Dryas marks the start of the Holocene, continuing to the present
    •   MIS 2 - 29 near Last Glacial Maximum
    •   MIS 3 - 57[a]
    •   MIS 4 - 71
    •   MIS 5 - 130, usually sub-divided into a to e:
    o   MIS 5a - 82
    o   MIS 5b - 87
    o   MIS 5c - 96
    o   MIS 5d - 109
    o   MIS 5e - 123 (Eemian or Ipswichian)
    •   MIS 6 - 191"
    « Last Edit: April 12, 2017, 04:29:58 PM by AbruptSLR »
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    AbruptSLR

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    Re: Conservative Scientists & its Consequences
    « Reply #1683 on: April 12, 2017, 04:38:56 PM »
    The linked reference very likely errs on the side of least drama (ESLD); but nevertheless, it finds that at least 20% more area of permafrost will be lost due a 2C GMSTA (above pre-industrial) than the previous state-of-the-art research indicated.  I believe that this research ESLD for reasons including: (a) GMSTA will most likely exceed 2C within the next two decades; (b) the research underestimates the impact of increasing rainfall, and thermokarst lake formation, on permafrost degradation; and (c) Arctic Amplification is likely higher/greater than the researchers assume.

    S. E. Chadburn, et. al. (2017), "An observation-based constraint on permafrost loss as a function of global warming", Nature Climate Change, doi:10.1038/nclimate3262

    http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate3262.html

    Extract: "Permafrost, which covers 15 million km2 of the land surface, is one of the components of the Earth system that is most sensitive to warming. Loss of permafrost would radically change high-latitude hydrology and biogeochemical cycling, and could therefore provide very significant feedbacks on climate change. The latest climate models all predict warming of high-latitude soils and thus thawing of permafrost under future climate change, but with widely varying magnitudes of permafrost thaw. Here we show that in each of the models, their present-day spatial distribution of permafrost and air temperature can be used to infer the sensitivity of permafrost to future global warming. Using the same approach for the observed permafrost distribution and air temperature, we estimate a sensitivity of permafrost area loss to global mean warming at stabilization of  million km2 °C−1 (1σ confidence), which is around 20% higher than previous studies. Our method facilitates an assessment for COP21 climate change targets: if the climate is stabilized at 2 °C above pre-industrial levels, we estimate that the permafrost area would eventually be reduced by over 40%. Stabilizing at 1.5 °C rather than 2 °C would save approximately 2 million km2 of permafrost."
    « Last Edit: April 12, 2017, 06:23:55 PM by AbruptSLR »
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    jai mitchell

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    Re: Conservative Scientists & its Consequences
    « Reply #1684 on: April 12, 2017, 05:11:20 PM »
    Those are good points ASLR,

    I find it very interesting that the climate models used for studying the regional Arctic warming project a nearly linear rate of degradation with temperature but we know that the rapid step loss of sea ice and subsequent albedo warming will produce a very non-linear jump in regional warming and permafrost decay.  Also, very astute to keep in mind the recent studies that show standing water as a primary driver for increased decomposition.  I would also suggest that increased boreal forest fires are also observed to increase decomposition rates and that the increase of microbial activity also provides a temperature feedback that, in some model scenarios, creates a self-sustaining reaction throughout much of the refreeze period.

    Finally, and this cannot be overstated, the climate models are very clearly understating global atmospheric changes, that we have very likely already crossed a threshold leading to near equable climate regimes in the boreal region, and that this reality won't be understood fully until anthropogenic aerosol emissions are reduced to near zero.
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    AbruptSLR

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    Re: Conservative Scientists & its Consequences
    « Reply #1685 on: April 12, 2017, 06:45:17 PM »
    Just to elaborate on my last Reply, I repost the following from the Human Stupidity thread:

    "Most decision makers assume that they are entitled to use Transient Climate Response, TCR, values in their policy making decisions; however, as indicated in the first attached image ECS is about 50% higher than TCR; while the linked 2015 PennState article entitled: "Earth System Sensitivity"; indicates that ESS is about 50% higher than ECS (see the second attached image).  Thus if TCR is at the high end of its estimated range, and as climate sensitivity is logarithmic with time, we could well see a lot higher effective climate response this century than most decision makers are expecting:

    https://www.e-education.psu.edu/meteo469/node/219

    Extract: "Studies using climate models that incorporate these slow feedbacks find that the Earth System sensitivity is indeed substantially greater than the nominal Charney sensitivity, roughly 50% higher."

    Caption for the second image: "Figure 8.12: Equilibrium warming as a function of CO2 concentration assuming a Charney sensitivity range of 3°C +/-1.5°C (lower curve=1.5°C, middle curve=3.0°C, upper curve=4.5°C), compared with actual estimates of CO2 concentration and global mean temperature for past geological periods where CO2 levels appear to have been higher than today (black circles)."

    Edit: I note that at the end of 2015 the equivalent carbon dioxide concentration value was 485ppm which is what counts when estimating temperature impacts; & I guess that this value was no less than 489ppm at the end of 2016."
    « Last Edit: April 13, 2017, 04:04:00 PM by AbruptSLR »
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    AbruptSLR

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    Re: Conservative Scientists & its Consequences
    « Reply #1686 on: April 19, 2017, 11:53:14 PM »
    The linked reference essentially means that the lower end of the AR5 range for ECS is not valid and should be removed from AR6 (although I am not convinced that it will be):

    Kyle C. Armour (2017), "Energy budget constraints on climate sensitivity in light of inconstant climate feedbacks", Nature Climate Change, doi:10.1038/nclimate3278

    http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate3278.html?WT.feed_name=subjects_climate-sciences


    Abstract: "Global energy budget constraints suggest an equilibrium climate sensitivity around 2 °C, which is lower than estimates from palaeoclimate reconstructions, process-based observational analyses, and global climate model simulations. A key assumption is that the climate sensitivity inferred today also applies to the distant future. Yet, global climate models robustly show that feedbacks vary over time, with a strong tendency for climate sensitivity to increase as equilibrium is approached. Here I consider the implications of inconstant climate feedbacks for energy budget constraints on climate sensitivity. I find that the long-term value of climate sensitivity is, on average, 26% above that inferred during transient warming within global climate models, with a larger discrepancy when climate sensitivity is high. Moreover, model values of climate sensitivity inferred during transient warming are found to be consistent with energy budget observations, indicating that the models are not overly sensitive. Using model-based estimates of how climate feedbacks will change in the future, in conjunction with recent energy budget constraints, produces a current best estimate of equilibrium climate sensitivity of 2.9 °C (1.7–7.1 °C, 90% confidence). These findings suggest that climate sensitivity estimated from global energy budget constraints is in agreement with values derived from other methods and simulated by global climate models."
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    AbruptSLR

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    Re: Conservative Scientists & its Consequences
    « Reply #1687 on: April 20, 2017, 12:01:44 AM »
    The linked article is entitled: "Photos Reveal More Than 200 Bright Blue Arctic Lakes Have Started Bubbling With Methane Gas", and it indicates that methane emissions from thermokarst lakes in Siberia are increasing rapidly; and yet the AR5 projections to not account for this positive feedback:

    http://www.sciencealert.com/photos-reveal-more-than-200-bright-blue-arctic-lakes-have-started-bubbling-with-methane-gas

    Extract: "Bogoyavlensky and his team identified the strange new lakes after studying satellite data from 2015 and 16, and are now monitoring them as an active source of methane emissions."
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    sidd

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    Re: Conservative Scientists & its Consequences
    « Reply #1688 on: April 20, 2017, 12:17:56 AM »
    Re: "The linked reference essentially means that the lower end of the AR5 range for ECS is not valid ..."

    Disagreed. From the abstract " best estimate of equilibrium climate sensitivity of 2.9 °C (1.7–7.1 °C, 90% confidence). " This agrees with AR5. It disagrees with some lowball estimates by Lewis and others based on energy balance considerations.

    AbruptSLR

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    Re: Conservative Scientists & its Consequences
    « Reply #1689 on: April 20, 2017, 03:52:58 AM »
    Re: "The linked reference essentially means that the lower end of the AR5 range for ECS is not valid ..."

    Disagreed. From the abstract " best estimate of equilibrium climate sensitivity of 2.9 °C (1.7–7.1 °C, 90% confidence). " This agrees with AR5. It disagrees with some lowball estimates by Lewis and others based on energy balance considerations.

    sidd,

    I can read as well an anybody; so I provide the attached image by the same author to use a picture to help clarify the pdf that the author is promoting, marked time dependent, has a very fat right-tail.

    Best,
    ASLR
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    sidd

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    Re: Conservative Scientists & its Consequences
    « Reply #1690 on: April 20, 2017, 05:48:21 AM »
    Re: sensitivity

    You are correct, I was wrong. From AR5, summary

    "The equilibrium climate sensitivity quantifies the response of the climate system to constant radiative forcing on multi-century time scales. It is defined as the change in global mean surface temperature at equilibrium that is caused by a doubling of the atmospheric CO 2 concentration. Equilibrium climate sensitivity is likely in the range 1.5°C to 4.5°C (high confidence), extremely unlikely less than 1°C (high confidence), and very unlikely greater than 6°C (medium confidence) [Ref 16] . The lower temperature limit of the assessed likely range is thus less than the 2°C in the AR4, but the upper limit is the same. This assessment reflects improved understanding, the extended temperature record in the atmosphere and ocean, and new estimates of radiative forcing. {TS TFE.6, Figure 1; Box 12.2} "

    This paper clearly pushes the high end out. I misremembered the high end in AR5, and should have looked it up first. Sorry.

    sidd

    jai mitchell

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    Re: Conservative Scientists & its Consequences
    « Reply #1691 on: April 20, 2017, 06:08:45 AM »
    They also used references that differed from their own projections for aerosols, neglecting to include the absent impact of upper tropospheric cooling from aerosols and the resultant LR/WV feedbacks associated with aerosol reduction.  In addition, their energy constraints exempted 95% of the model runs and their period of study (mid 2000s) included the period of time when China increased their aerosol emissions to levels (globally) not seen since the early 1970s.
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    Re: Conservative Scientists & its Consequences
    « Reply #1692 on: April 20, 2017, 12:06:20 PM »
    I had limited time available when I made my Replies #1687 & #1689, as the right-skew of Armour's ECS pdf based on a subset of modern observations was not the only point that I wanted to make with regard to AR5's treatment of ECS, which is that:

    1. All assessment reports, ARs, merely aggregate reported ECS estimates from studies within the extant peer-reviewed literature, so the confidence ranges that sidd quotes from AR5 accounts for ECS estimates from: a. observations, b. paleo-data and c. computer models; without normalizing any of the reported data for issues like time-dependence, climate-state, or rate of radiative forcing.

    2. Thus when Armour takes the observation-based estimates and corrects those estimates for time-dependence; in order to avoid double counting, one should remove the observation-based estimates of ECS used in AR5 and replace them with the time-dependent corrected estimates by Armour (which, if one did so would shift the confidence ranges reported by AR5).

    3. As jai points-out the observation-based estimates used in AR5 could also be corrected for anthropogenic aerosol radiative forcing influences extant during the observation period (mid 2000s), but his point about radiative forcing also applies to solar radiative fluctuations, volcanic aerosol-induced radiative fluctuations etc.

    4. Climate-state corrections can also be made to account for fluctuations in energy absorbed by the oceans (due to ENSO, PDO, etc) and by fluctuations in albedo (particularly in the polar regions).  This last point is important as we all remember well Hansen's warnings about the coming Arctic albedo-flip when the Arctic Sea Ice area drops; which will change future values of ECS.

    5. ECS can also be corrected for rates of change in radiative forcing (we are currently at a pessimum point w.r.t. to the influence of rate of forcing, so both faster and slower rates of change will increase ECS) and for global mean surface temperature levels (ECS in ice ages is different than in interglacial periods).

    Thus AR5's confidence ranges are only of value if one has read all of the reports and corrected all of their estimated values of ECS for such factors as time-dependence, climate-state, rate of change of radiative forcing, and errors in the data bases used (such as under representing Arctic temperature values).  Lastly, I would like to emphasize that there will be only one effective ECS value that will occur in the coming decades (say until the WAIS collapse induces a surge in Hansen's ice-climate positive feedback) and it will include non-stationary contributions from long-term ESS feedbacks such as from permafrost degradation (including from methane emissions from thermokarst lakes); reductions in aerosol radiative forcing as anthropogenic aerosol emissions are reduced, and ENSO & Arctic amplification.

    Mother Nature does not care what AR5 reports.
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    AbruptSLR

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    Re: Conservative Scientists & its Consequences
    « Reply #1693 on: April 20, 2017, 06:42:41 PM »
    In my last post I did not directly address Hansen's ice-climate positive feedback mechanism on ECS, due to a progressive collapse of the WAIS this century (& which could begin as soon as with about twenty years), so I provide the following recent posts from other threads, that indicate that paleo-evidence confirms that a collapse of marine ice sheets in Antarctica accelerates Arctic Amplification (due to Hansen's ice-climate feedback & the bipolar seesaw mechanism); which can in-turn amplify ENSO-like behavior that can telecommunicate more atmospheric energy from the Tropical Pacific poleward (& particularly towards West Antarctica thus sustaining a collapse of the WAIS begun in the Byrd Subglacial Basin).  If so this would dramatically increase the effective value of ECS this century:

    Extract from the Human Stupidity thread:'

    'The first linked article is entitled: "3M-year-old sediment tells the story of today's climate", and it discusses research about Lake El'gygytgyn, in Siberia, that began in 2009.  Even through the findings of this research has been available for years (see the last two linked references), ESMs have not been able to replicate that amount of Arctic Amplification documented by the Lake El'gygytgyn physical evidence.  This implies that the climate sensitivity of current ESMs need to be increased to appropriate capture the climate change risks (including Hansen's ice-climate feedback mechanism due to 'freshwater hosing' that we are collectively exposing ourselves to.

    https://www.eenews.net/stories/1060053182

    Extract: "One of the "most astounding things" in the sediment, she said, was evidence that ancient summer temperatures in the region had spiked by as much as 14 degrees Fahrenheit higher than today, not just once, but several times in the past.

    There is no direct way to measure the atmosphere of this ancient time, but repeated estimates from leaf stomata, ocean fossil studies and other remnants now put its carbon dioxide content at around 400 parts per million — about where it is today, largely due to the sharp rise of CO2 and other greenhouse gases since the Industrial Revolution began, literally gaining steam in the 1850s.

    According to Brigham-Grette, that means the Earth is much more sensitive to climate change now, and it is speeding up as the planet tries to reach equilibrium from the new injection of heat.

    The findings of the science team at Lake El'gygytgyn were also very hard for experts who use computer-driven climate models to understand. They pride themselves on being able to predict the speed of climate change in the future and also in the past by use of a technique called "hindcasting."

    In the case of the late Pliocene, though, the models missed the ice melting. Yet the data collected from drilling in the Arctic and more recently from the Antarctic suggest it happened not just once, but repeatedly at both poles.

    James White, a paleoclimatologist and climate modeler at the University of Colorado, Boulder, said Brigham-Grette's study is "one of the more important paleoclimate studies of the last 10 years."

    "The fact that we don't get the Pliocene is a concern," he explained, because over the years, the modelers and the data gatherers have helped each other perfect their understanding of climate change and how to improve the models.

    "We're not in equilibrium now, not even close," he asserted, as the planet's oceans struggle to distribute the new influx of heat.

    A new Japanese study, published in February written by scientists from a team exploring ice cores drilled in Antarctica, found that ocean warming currents carrying heat from the tropics have become more unstable in the North Atlantic because of colder fresh water dripping from the melting ice of glaciers in Greenland. The phenomenon is called "freshwater hosing," which also appears to have happened in the ancient past.

    "There's this attitude of 'Well, we're Americans, and we're going to tough it out and help people rebuild along our coastlines,'" she said. "Well, that's sort of stupid, because we're putting people and infrastructure back in harm's way.""


    Gregory A. De Wet, Isla S. Castañeda, Robert M. DeConto & Julie Brigham-Grette  (February 2016), “A high-resolution mid-Pleistocene temperature record from Arctic Lake El'gygytgyn: A 50 kyr super interglacial from MIS 33 to MIS 31?”Earth and Planetary Science Letters 436:56-63 DOI: 10.1016/j.epsl.2015.12.021 

    http://blogs.umass.edu/biogeochem/files/2016/01/de-Wet-et-al.-2016.pdf

    &

    Coletti, A. J., DeConto, R. M., Brigham-Grette, J., and Melles, M.: A GCM comparison of Pleistocene super-interglacial periods in relation to Lake El'gygytgyn, NE Arctic Russia, Clim. Past, 11, 979-989, doi:10.5194/cp-11-979-2015, 2015.

    http://www.clim-past.net/11/979/2015/cp-11-979-2015.pdf
    http://www.clim-past.net/11/979/2015/cp-11-979-2015.html
    "


    Extract from Hansen et al paper3+ meters SLR by 2100 thread:

    "The Last Glacial Termination, LGT, occurred from 18,000 to 11,650 kya, and the following reference, reconstructs the dynamic response of the Antarctic ice sheets to warming in this period in order to better evaluate Hansen's ice-climate feedback mechanisms.  The abstract concludes: "Given the anti-phase relationship between inter-hemispheric climate trends across the LGT our findings demonstrate that Southern Ocean-AIS feedbacks were controlled by global atmospheric teleconnections.  With increasing stratification of the Southern Ocean and intensification of mid-latitude westerly winds today, such teleconnections could amplify AIS mass loss and accelerate global sea-level rise."

    Fogwill, et. al. (2017), "Antarctic ice sheet discharge driven by atmosphere-ocean feedbacks at the last Glacial Termination", Scientific Reports 7, Article number 39979, doi:10.1038/srep39979

    https://www.nature.com/articles/srep39979


    See also:
    http://www.geosci-model-dev-discuss.net/gmd-2017-18/gmd-2017-18.pdf
    "
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    AbruptSLR

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    Re: Conservative Scientists & its Consequences
    « Reply #1694 on: April 20, 2017, 08:48:07 PM »
    The linked research indicates that current climate models are underestimating the amount of observed Arctic Amplification.

    Anais J. Orsi, et. al. (17 April 2017), "The recent warming trend in North Greenland", Geophysical Research Letters, DOI: 10.1002/2016GL072212 

    http://onlinelibrary.wiley.com/doi/10.1002/2016GL072212/full

    Abstract: "The Arctic is among the fastest warming regions on Earth, but it is also one with limited spatial coverage of multi-decadal instrumental surface air temperature measurements. Consequently, atmospheric reanalyses are relatively unconstrained in this region, resulting in a large spread of estimated 30-year recent warming trends, which limits their use to investigate the mechanisms responsible for this trend.

    Here, we present a surface temperature reconstruction over 1982-2011 at NEEM (51∘ W, 77∘ N), in North Greenland, based on the inversion of borehole temperature and inert gas isotope data. We find that NEEM has warmed by 2.7±0.33∘C over the past 30 years, from the long-term 1900-1970 average of -28.55±0.29∘C. The warming trend is principally caused by an increase in downward longwave heat flux. Atmospheric reanalyses underestimate this trend by 17%, underlining the need for more in situ observations to validate reanalyses."
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    Re: Conservative Scientists & its Consequences
    « Reply #1695 on: April 24, 2017, 02:24:49 AM »
    The linked open access reference indicates that: "… sea ice will completely disappear in the Barents and Kara Seas by around 2025"; which is clearly an indication that Arctic Amplification is greater than AR5 acknowledges:

    Kim, K.-Y., Kim, J., Yeo, S., Na, H., Hamlington, B. D., and Leben, R. R. (2017), "Understanding the Mechanism of Arctic Amplification and Sea Ice Loss", The Cryosphere Discuss., doi:10.5194/tc-2017-39

    http://www.the-cryosphere-discuss.net/tc-2017-39/

    Abstract. Sea ice reduction is accelerating in the Barents and Kara Seas. Several mechanisms are proposed to explain the accelerated loss of polar sea ice, which remains an open question. In the present study, the detailed physical mechanism of sea ice reduction in winter is identified using the daily ERA interim reanalysis data. Downward longwave radiation is an essential element for sea ice reduction, but can only be sustained by excessive upward heat flux from the sea surface exposed to air in the region of sea ice loss. The increased turbulent heat flux is used to increase air temperature and specific humidity in the lower troposphere, which in turn increases downward longwave radiation. This feedback process is clearly observed in the Barents and Kara Seas in the reanalysis data. A quantitative assessment reveals that this feedback process is amplifying at the rate of ~ 8.9 % every year during 1979–2016. Based on this estimate, sea ice will completely disappear in the Barents and Kara Seas by around 2025. Availability of excessive heat flux is necessary for the maintenance of this feedback process; a similar mechanism of sea ice loss is expected to take place over the sea-ice covered polar region when sea ice is not fully recovered in winter.
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    Re: Conservative Scientists & its Consequences
    « Reply #1696 on: April 24, 2017, 03:17:42 PM »
    And this is what we are currently seeing in the winter...increased humidity and clouds causing dramatic warm winter anomalies due to downward longwave radiation. This has been getting worse for at least 2 decades and represents a tipping point for the Arctic. We are seeing knock off effects all across the northern hemisphere, large positive fall snow cover anomalies being one and large changes in NH atmospheric circulation, another (cyclone cannons).

    AbruptSLR

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    Re: Conservative Scientists & its Consequences
    « Reply #1697 on: April 25, 2017, 02:01:22 AM »
    And this is what we are currently seeing in the winter...increased humidity and clouds causing dramatic warm winter anomalies due to downward longwave radiation. This has been getting worse for at least 2 decades and represents a tipping point for the Arctic. We are seeing knock off effects all across the northern hemisphere, large positive fall snow cover anomalies being one and large changes in NH atmospheric circulation, another (cyclone cannons).

    The linked Scribbler article is entitled: "Hauntingly Freakish Siberian Wildfires Now Flicker to Life in April".  High Arctic Amplification is an indication of high climate sensitivity.


    https://robertscribbler.com/2017/04/24/hauntingly-freakish-siberian-wildfires-now-flicker-to-life-in-april/

    Extract: "This past winter has been ridiculously warm for large sections of Siberia. From the Yamal Peninsula to Lake Baikal to the thinning ice of the Arctic Ocean and back down to the Sea of Okhotsk, temperatures have ranged from 4 to nearly 7 degrees Celsius above normal throughout the entire first quarter of 2017."
    “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: Conservative Scientists & its Consequences
    « Reply #1698 on: April 25, 2017, 05:01:16 PM »
    exhibit A: 

    Polar regions: Arctic sea-ice future, Antarctic ice-shelf stability, and glacial landforms (EGU17)

    Published on Apr 25, 2017
    European Geosciences Union Media at General Assembly 25 April 2017. The polar regions, at the north and southern extremes of our planet, are some of the most unique and fragile areas on Earth.

    The Arctic is warming twice as fast as the global average, with drastic consequences for the sea-ice cover in the region, which hit its lowest annual extent on record in 2016.

    A talk at this press conference will look into what 2016 Arctic sea ice can tell us about future sea-ice conditions in the region. We will also hear about how future Arctic sea-ice cover will differ for 1.5 and 2°C, the two global warming limits in the Paris Agreement.

    Moving south, another presentation will look into the impact that warm winds (Foehn winds) are having on the weather, climate and ice shelves in Antarctica, specifically Larsen C. This ice shelf is located in the Antarctic Peninsula, the fastest warming region on Earth in the late 20th century, and is at risk of collapse.

    This press conference will end with the presentation of a new seabed map of the polar regions, an atlas of submarine glacial landforms with stunning images.
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    Re: Conservative Scientists & its Consequences
    « Reply #1699 on: May 08, 2017, 08:30:07 PM »
    The linked reference finds that upper ocean dissolved oxygen levels are declining two to three times faster with global warming than previously projected.  This could eventually reduce the ocean's ability to absorb CO₂, which would create a new positive feedback mechanism for global warming (not to mention that it would also increase the risks of mass extinctions):

    Takamitsu Ito, Shoshiro Minobe, Matthew C. Long and Curtis Deutsch (April 2017) "Upper Ocean O2 trends: 1958-2015,” (Geophysical Research Letters, DOI: 10.1002/2017GL073613

    http://onlinelibrary.wiley.com/doi/10.1002/2017GL073613/full

    Abstract: "Historic observations of dissolved oxygen (O2) in the ocean are analyzed to quantify multi-decadal trends and variability from 1958 to 2015. Additional quality control is applied and the resultant oxygen anomaly field is used to quantify upper ocean O2 trends at global and hemispheric scales. A widespread negative O2 trend is beginning to emerge from the envelope of interannual variability. Ocean reanalysis data is used to evaluate relationships with changes in ocean heat content (OHC) and oxygen solubility (O2,sat). Global O2 decline is evident after the 1980s, accompanied by an increase in global OHC. The global upper ocean O2 inventory (0-1,000m) changed at the rate of -243±124TmolO2 per decade. Further, the O2 inventory is negatively correlated with the OHC (r=-0.86; 0-1,000m) and the regression coefficient of O2 to OHC is approximately −8.2±0.66 nmol O2 J−1, on the same order of magnitude as the simulated O2-heat relationship typically found in ocean climate models. Variability and trends in the observed upper ocean O2 concentration are dominated by the Apparent Oxygen Utilization (AOU) component with relatively small contributions from O2,sat. This indicates that changing ocean circulation, mixing and/or biochemical processes, rather than the direct thermally-induced solubility effects, are the primary drivers for the observed O2 changes. The spatial patterns of the multi-decadal trend include regions of enhanced ocean deoxygenation including the subpolar North Pacific, eastern boundary upwelling systems and tropical oxygen minimum zones. Further studies are warranted to understand and attribute the global O2 trends and their regional expressions.

    See also the linked ThinkProgress article by Joe Romm, entitled: "Carbon pollution is suffocating ocean life and speeding up the next mass extinction".

    https://thinkprogress.org/oxygen-levels-falling-2-to-3-times-faster-than-predicted-in-our-warming-oceans-7c1e9b48cd42

    Extract: "Oxygen levels ‘falling 2 to 3 times faster than predicted’ in our warming oceans, study finds"
    “It is not the strongest or the most intelligent who will survive but those who can best manage change.”
    ― Leon C. Megginson