feedbacks, are they important?

Discussion in 'Environment' started by Old Rocks, Oct 2, 2012.

  1. Old Rocks
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    Old Rocks Diamond Member

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    TC - Abstract - Uncertainties in the global temperature change caused by carbon release from permafrost thawing

    Uncertainties in the global temperature change caused by carbon release from permafrost thawing

    E. J. Burke1, I. P. Hartley2, and C. D. Jones1
    1Met Office Hadley Centre, FitzRoy Road, Exeter, EX1 3PB, UK
    2Geography, College of Life and Environmental Sciences, University of Exeter, Rennes Drive, Exeter, EX4 4RJ, UK

    Abstract. Under climate change thawing permafrost will cause old carbon which is currently frozen and inert to become vulnerable to decomposition and release into the climate system. This paper develops a simple framework for estimating the impact of this permafrost carbon release on the global mean temperature (P-GMT). The analysis is based on simulations made with the Hadley Centre climate model (HadGEM2-ES) for a range of representative CO2 concentration pathways. Results using the high concentration pathway (RCP 8.5) suggest that by 2100 the annual methane (CH4) emission rate is 2–59 Tg CH4 yr−1 and 50–270 Pg C has been released as CO2 with an associated P-GMT of 0.08–0.36 °C (all 5th–95th percentile ranges). P-GMT is considerably lower – between 0.02 and 0.11 °C – for the low concentration pathway (RCP2.6). The uncertainty in climate model scenario causes about 50% of the spread in P-GMT by the end of the 21st century. The distribution of soil carbon, in particular how it varies with depth, contributes to about half of the remaining spread, with quality of soil carbon and decomposition processes contributing a further quarter each. These latter uncertainties could be reduced through additional observations. Over the next 20–30 yr, whilst scenario uncertainty is small, improving our knowledge of the quality of soil carbon will contribute significantly to reducing the spread in the, albeit relatively small, P-GMT
     
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  2. Old Rocks
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    Old Rocks Diamond Member

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    AGW Observer

    Permafrost carbon release could lead to significant warming even under less intensive emissions trajectories

    Significant contribution to climate warming from the permafrost carbon feedback – MacDougall et al. (2012)

    Abstract: “Permafrost soils contain an estimated 1,700 Pg of carbon, almost twice the present atmospheric carbon pool. As permafrost soils thaw owing to climate warming, respiration of organic matter within these soils will transfer carbon to the atmosphere, potentially leading to a positive feedback. Models in which the carbon cycle is uncoupled from the atmosphere, together with one-dimensional models, suggest that permafrost soils could release 7–138 Pg carbon by 2100 (refs 3, 4). Here, we use a coupled global climate model to quantify the magnitude of the warming generated by the feedback between permafrost carbon release and climate. According to our simulations, permafrost soils will release between 68 and 508 Pg carbon by 2100. We show that the additional surface warming generated by the feedback between permafrost carbon and climate is independent of the pathway of anthropogenic emissions followed in the twenty-first century. We estimate that this feedback could result in an additional warming of 0.13–1.69 °C by 2300. We further show that the upper bound for the strength of the feedback is reached under the less intensive emissions pathways. We suggest that permafrost carbon release could lead to significant warming, even under less intensive emissions trajectories.”

    Citation: Andrew H. MacDougall, Christopher A. Avis & Andrew J. Weaver, Nature Geoscience, 2012, doi:10.1038/ngeo1573
     
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  3. CrusaderFrank
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    CrusaderFrank Diamond Member

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    600,000 consecutive years of data from Vostok says you have it backwards, CO2 lags temperature
     
  4. RollingThunder
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    RollingThunder VIP Member

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    That's just your ignorant and very retarded take on it, CrazyFruitcake. The scientists who study this say different. Even if you're too screwed up and brainwashed to tell the difference, most people know which one they'd trust to give them accurate information when it is between some anonymous nutjob on a debate forum or peer-reviewed scientific papers in top notch science journals.


    [ame=http://www.youtube.com/watch?v=hWJeqgG3Tl8]Climate Denial Crock of the Week - The Temp leads Carbon Crock - YouTube[/ame]
     
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    Last edited: Oct 2, 2012
  5. flacaltenn
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    flacaltenn USMB Mod Staff Member Gold Supporting Member

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    You're really a nasty little fairy ain'tcha Tink?

    When you pounce like that before you engage your brain -- it really shows how little effort you put into this.. Frank was making a cogent point..

    When the Arctic temps INCREASE, icy stuff melts and we do see GHG emission as a result --- These feedbacks ARE BY DEFINITION ----- an example of CO2 increases FOLLOWING temperature spikes. Really is the very nature of a feedback when the excitation is TEMPERATURE.

    Even that Shakun 2012 pile you laid on us DEPENDS on an "unspecific" INITIAL INCREASE in temperature to start liberating CO2 from the frozen ICE age tundra...
     
  6. RollingThunder
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    RollingThunder VIP Member

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    You're a massively retarded little piece of shit ain'tcha fecalhead?




    CrazyFruitcake's specious 'points' only seem "cogent" to you because you're as retarded as he is.





    Increased CO2 levels in the atmosphere cause warming. That's a fact based on the laws of physics and verified by many decades of observation of the real world. It doesn't really matter if at times in the past other influences (warming from natural cycles, extreme vulcanism, etc.) caused the initial increase in CO2 levels. The point remains that the increased CO2 was the main cause of the subsequent warming. Currently mankind is adding massive quantities of CO2 to the atmosphere every year and that extra CO2 is producing the current abrupt warming trend.
     
  7. westwall
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    westwall USMB Mod Staff Member Gold Supporting Member Supporting Member

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    An entire religion based on computer models....you guys crack me up.
     
  8. Old Rocks
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    Old Rocks Diamond Member

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    Now Walleyes, were you to actually read the article, they are trying to determine the feedback that they will get to from thawing of the permafrost. They do so by taking known data points and extrapolating differant emission scenerios.

    But then again, trying to use presently known data to extrapolate future events is application of science. Whether you are estimating the creep of a hillside or the emissions from permafrost. It is called science, something you are obviously unfamiliar with.
     
  9. RollingThunder
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    RollingThunder VIP Member

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    And we get a big chuckle watching a cult based on reality denial (and full of clueless retards) melt down as reality wins and the cultic myths go down in flames.
     
  10. westwall
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    westwall USMB Mod Staff Member Gold Supporting Member Supporting Member

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    They are using models, based on other models, that use data that was generated by other models. There is very little real observed science there olfraud. When that changes I will begin to pay attention to what they have to say. Of course their models need to do better than a Random Walk as well, aaaaannnd that will no doubt take a reaally long time, but hey, at least it's a MEASURABLE benchmark, unlike everything else they spew out.
     

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