Last year much was made by climate-change deniers of a poorly referenced section of one of the IPCC reports of 2007 that said “up to 40% of the Amazon rainforest could be sensitive to future changes in rainfall.” It turned out that the claim was based on solid science, despite the best efforts of those who just can’t bring themselves to trust professional climatologists. You can read the whole sordid tale here. I revisit the issue because of a new paper about to be published by the American Geophysical Union that bears on this question.


“Widespread Decline in Greenness of Amazonian Vegetation Due to the 2010 Drought” isn’t available to the public yet, although there’s a press release here. The upshot is it’s beginning to look even more worrisome in the Amazon than previously thought. The 2007 IPCC reports used research on the 2005 drought that affected the rainforest there in ways that were subject to some debate. There is now less uncertainty about whether the forest gained or lost vegetative cover in the wake of that drought. The authors of new paper write:

Undisturbed Amazon rainforests were reported to have greened-up during the 2005 drought based on analysis of a previous version of the Enhanced Vegetation Index (EVI) data [Saleska et al., 2007]. This has now been shown not to be the case…

Why does all this matter?

There is concern that in a warming climate the ensuing moisture stress could result in Amazonian rainforests being replaced by savannas [Cox et al., 2004; Salazar et al., 2007; Huntingford et al., 2008; Malhi et al., 2008], in which case the large reserves of carbon stored in these forests, about 100 billion tons [Malhi et al., 2006], could be released to the atmosphere, which in turn would accelerate global warming significantly.

It is understandable, to an extent, why some people would be upset that the IPCC report referenced a non-peer-reviewed World Wide Fund for Nature paper, rather than the genuine science from which the WWF drew its conclusions. The fate of the Amazon will have a huge effect on the global climate, and careless citation won’t help make the case for doing something about it. But those who argued, before bothering to do even cursory research into the matter (like talking with an actual scientist), were even sloppier. I draw the guilty parties’ attention to the the full abstract of the new paper.

During this decade, the Amazon region has suffered two severe droughts in the short span of five years – 2005 and 2010. Studies on the 2005 drought present a complex, and sometimes contradictory, picture of how these forests have responded to the drought. Now, on the heels of the 2005 drought, comes an even stronger drought in 2010, as indicated by record low river levels in the 109 years of bookkeeping. How has the vegetation in this region responded to this record-breaking drought? Here we report widespread, severe and persistent declines in vegetation greenness, a proxy for photosynthetic carbon fixation, in the Amazon region during the 2010 drought based on analysis of satellite measurements. The 2010 drought, as measured by rainfall deficit, affected an area 1.65 times larger than the 2005 drought – nearly 5 million km2 of vegetated area in Amazonia. The decline in greenness during the 2010 drought spanned an area that was four times greater (2.4 million km22 and more severe than in 2005. Notably, 51% of all drought-stricken forests showed greenness declines in 2010 (1.68 million km2) compared to only 14% in 2005 (0.32 million km2). These declines in 2010 persisted following the end of the dry season drought and return of rainfall to normal levels, unlike in 2005. Overall, the widespread loss of photosynthetic capacity of Amazonian vegetation due to the 2010 drought may represent a significant perturbation to the global carbon cycle.

In case anyone is wondering, “a significant perturbation to the global carbon cycle” is not a good thing.

And things aren’t any better in the Indonesia rainforests.

Comments

  1. #1 maxwell
    March 30, 2011

    “In case anyone is wondering, “a significant perturbation to the global carbon cycle” is not a good thing.”

    Care to dispense with some evidence for such a claim?

    My wife was ‘a significant perturbation to my personal life cycle’. It has been pretty great so far.

  2. #2 Sab
    March 30, 2011

    @1: Try typing “a significant perturbation to the global carbon cycle” into a search engine and looking at the primary literature that comes up. Its not difficult. If you don’t have access to the scientific literature why not take a look at the websites for a major university or two? They tend to have information on the global carbon cycle freely available.

    However, if you just want to play a game of false equivalence: Did your wife cause significant acidification of the world’s oceans? How about changing the albedo of the earth’s surface by switching forests for grasslands? Did she accelerate glacial and polar melting with a knock-on impact on fresh water stores, albedo (again) and release of methane from permafrost? I’d be surprised if your wife alone was responsible for increasing atmospheric CO2 content through microbial decomposition. Can she affect the agricultural capacity of large areas of the earth’s surface? Maybe she has a special power that allows her to alter global moisture patterns?

  3. #3 madjack
    March 30, 2011

    ‘My wife was ‘a significant perturbation to my personal life cycle’. It has been pretty great so far. ‘

  4. #4 madjack
    March 30, 2011

    This weeks dumbest comment award winner?

  5. #5 maxwell
    March 31, 2011

    Sab,

    I’ll pass on making other people’s arguments for them. If James wants to make a scientific claim, let him back it up. That’s called ‘debate’. Maybe you should Google that one.

    madjack,

    at least I can get everything into one comment, dumb or not. We could also try determining whether ‘the significant perturbation of a Hamiltonian of LHII by sunlight’ is a good thing. Or any other permutation of a parameter that changes in place of the ‘global carbon cycle’.

    James standard is simply saying that the perturbation is ‘significant’. Therefore it is bad.

    That’s not a very good standard for establishing facts. Then again, I don’t think that was his intention.

  6. #6 maxwell
    March 31, 2011

    …looking into this issue a bit more, it seems that there might be some concern over the original claims of Amazonian susceptibility to climate change.

    The organization that originally produced the research backing such a claim no longer has the original document available for perusing on their website. The Amazon Environmental Research Institute’s (AERI, http://www.ipam.org.br/) document supposedly used by WWF, Fire in the Amazon (according to Deltoid ), is no longer in their archive. So it’s hard to assess the value of the research that supposed ‘good enough’ for the IPCC to rely upon.

    If anyone can track down the pdf of this document, I would very much like to see it.

    More than that, there seems to be some kind of cognitive dissonance on the part of Joe Romm, Deltoid and James on this issue. The Amazon Environmental Research Institute is an NGO. Their ‘about’ page explains how they want to be involved in shaping policy with respect to forest management by the local, state and federal governments of Brazil. They gather scientific information that they hope supports those policies as well as supporting the rights of the indigenous peoples.

    Those are all worth while positions to support in my opinion. But they are also not strikingly different from policy positions of WWF. In fact, from the most recent sets of documents AERI has produced tie together deforestation and carbon emissions in a way that seems to promote compensation for Brazil not to cut down trees as a strategy for mitigating climate change. Being the organization that designs the policies as well as produces the ‘science’ to support those policies seems like a bit of a conflict of interest to me.

    More than that, how can we continue to support a conclusion from a document that does not even exist anymore? It may even be that the reference to this AERI document in the WWF report cited by the IPCC was deleted (also according to the Deltoid post) because the document could not be found prior to WWF publication.

    We’ll probably never know. But because a couple researchers get a retraction of a story due to the lack of due diligence of a specific reporter is not grounds to accept specific scientific conclusions. Especially in a case where the document which supports such a conclusion is no longer available for consumption.

    Not anywhere in any of links either here, at ClimateProgress or Deltoid is the actual document discussed. It’s a matter of lack of due diligence by the media, which in the minds of Romm and Lambert seems to imply that the research was sound and irrefutable. Fuzzy logic by any standard.

    I also got a chance to look at the paper who press release is discussed above (university license for researchers) and it seems pretty sound. Satellite measurements from NASA satellites. They do mention, but do not detail, a procedure for eliminating ‘atmospheric corruption’ of the satellite data. That would be interesting to read more about.

    All in all, jumping on headlines concerning recently published scientific results is problematic. Making serious conclusions based on such results is even worse.

  7. #7 Finch
    March 31, 2011

    Sitting here with my
    Gouldian Finch and reading the article I cannot help but wonder when people will come to the conclusion that our environment is to be protected.

  8. #8 daedalus2u
    March 31, 2011

    Maxwell, coal production is ~7 billion tons a year. That is ~6 billion tons of carbon. Releasing 20x that much carbon in a few years would be “significant”.

    100 billion tons of carbon is 370 billion tons of CO2.

    I calculate that adding that much CO2 to the atmosphere would increase it by ~60 ppm.

    It took ~40 years to raise the Earth’s CO2 level by 60 ppm to what it is now. Doing that in a few years is something I would call “significant”.

    If you put the title:

    Widespread Decline in Greenness of Amazonian Vegetation Due to the 2010 Drought

    Into google scholar, it shows a pdf which I downloaded and read.

  9. #9 Sab
    April 1, 2011

    Nice try maxwell :P

    I see you want people to believe that you are actually interested in the topic. Well, if you were really interested you wouldn’t have started off with a tiny piece of inane drivel about your wife. Lets get pedantic shall we?

    ‘In case anyone is wondering, “a significant perturbation to the global carbon cycle” is not a good thing.’

    Regardless of whether you agree with the findings of the (freely available) paper at hand, the statement above is true (go and read up about ecology, geology, palaeoecology, evolution, crop science, etc if you still can’t understand why). Out of a 667 word blog post about drought in the amazon you decided to try and score cheap points, but foolishly picked the least debatable part of the entire post (and then made a complaint about debate…aw how sweet). Attempting to compare significant perturbations of the global carbon cycle with your marriage is, to be charitable, utterly moronic.

    ——————-

    To anyone who is actually interested in the article:

    Having just read the paper I really wish people wouldn’t insist on sticking important info in ‘auxiliary methods’. I know why they did it, GRL gives you a very small word/page limit, its just becoming frustratingly common. I’m assuming they corrected their results downwards to compensate for the slight increase Adler et al. noted, but Xu et al only mention it tangentially as far as I can see :/ Did I miss something? Beer may have interfered with play by this point :P

  10. #10 maxwell
    April 3, 2011

    dedalus2u,

    the ‘significance’ of this research is not in the context of human emitted CO2, which I agree, is a significant perturbation.

    This is a matter of saying that because this paper is researching a proxy for the carbon cycle (greenness) in the Amazon they believe the decline in the uptake of CO2 by portions of South American will affect the carbon cycle globally. An effect James assumes will be negative although there is no substantiating evidence to support such a claim on annual to decadal time scales.

    Sab,

    I think you’re really barking up the wrong tree. Having gone through a great deal of literature on past climatic events, there nothing published that shows with any type of confidence what a small percentage change in the CO2 uptake by a very small region of the surface of the earth will do to the carbon cycle on transient time scales.

    Nothing.

    So to make a conclusion as to which direction, positive or negative (which are also poorly defined in the context of this discussion), seems pretty stupid to me. You can disagree. I simply provided two examples of situations in which ‘significant perturbations’ did not result in bad things happening. That seems straightforward to me. Again, you’re entitled to disagree.

    As to my picking out that statement, there was also an entire press release and paper from which James picked out a hypothesis on a global response to this drought to highlight. I have yet, however, to see your reprimanding him for highlighting that poorly suppported statement. An unevenly application of standards if I’ve seen one.

    As to the paper itself,

    I agree that not having an ‘experimental’ section to paper is a detriment in my opinion. I already pointed out that the comment above. The algorithm to rid the data of ‘atmospheric corruption’ seems like most substantiated contribution this paper makes. It would interesting to me to see how they correct for a spatially and temporally heterogeneous background for monthly time scales. From the perspective of an optical physics who does optical signal processing every day, that seems like useful information.

  11. #11 daedalus2u
    April 3, 2011

    No Max, you don’t understand the research and its implications. If the Amazon converts from tropical rain forest to savanna, the standing biomass goes away. Either it burns, or it decays. In both cases it gets converted to CO2. That is 100 billion tons of carbon in the standing biomass that gets converted into CO2.

    100 billion tons of carbon is not a small amount. It is not a small percentage of the yearly change. It is 40 years worth of change.

    This paper is not about a small change in CO2 uptake in the Amazon. It is about the Amazon changing from a significant net sink to a gigantic source.

    Why are you quibbling about whether that change is “significant” or not? Are you that ignorant? You say you have read a lot, but you clearly are ignorant of the implications of this research.

  12. #12 maxwell
    April 3, 2011

    daedulus2u,

    here is the quote of interest from the press release,

    ‘Overall, the widespread loss of photosynthetic capacity of Amazonian vegetation due to the 2010 drought may represent a significant perturbation to the global carbon cycle.’

    Please show me where they say ‘savanna’?

    I made no statements about whether the transformation of the Amazon to savanna would or would not be a significant perturbation. That you would make that conclusion shows more about your determined misunderstanding of my position than anything I have said or led on.

    To point out that the transformation of the rain forest to savanna is a ‘significant perturbation’ is a completely different hypothesis.

    This paper does not show that substantial portions of the Amazon are at risk of becoming savanna in any meaningfully short time scale. So the narrative that this research community uses to frame the work in which they partake is not worth note in the context of the actual quote James decided to highlight.

    So, I am fully aware of ‘the research and its implications’. I’m simply more careful about which statements are worth support and which ones are not.

    Are you that ignorant that you can’t decipher contexts effectively?

  13. #13 daedalus2u
    April 4, 2011

    What is your point? The press release does mention the Amazon rain forest turning into savanna. The press release does not contain the quote you are attributing to it.

    You want to cherry pick one sentence that says it “may represent a significant perturbation” and jump all over it while ignoring the larger implications. Any you call me ignorant?

    What is your point?

  14. #14 maxwell
    April 4, 2011

    d,

    I have several points.

    First, you mistook my original argument. Then you attributed my argument to something I never said nor meant.

    I have already made the point,

    ‘All in all, jumping on headlines concerning recently published scientific results is problematic. Making serious conclusions based on such results is even worse.’

    to James in particular, but I’ll also make it to you since you seem to not grasp the context of this conversation.

    You’re right that I mis-attributed the quote. It’s from the actual paper, not the press release, which further hammers home my point concerning the context of James’ conclusion with reference to actual research being put forth here.

    We have so little information on the response of the ‘global carbon cycle’ to the decreased photosynthetic capacity of the Amazon due to a drought that making statements as to ‘good’ or ‘bad’ outcomes from such an event is fairly meaningless. Just as my statements concerning my wife’s role as a significant perturbation on my life is rather meaningless.

    On top of that, we have little to no information on how much this drought will affect the forest’s ability to stave off fires or other processes that might lead to the transformation to savanna. So your points related to that ‘threat’ are without merit in this conversation as well.

    Then, after butchering my argument and imposing on me conclusion that I did not make, you referred to my knowledge of the framing of this research as ‘ignorant’. Now you want to get offended after I point your ignorance of the context of this entire conversation?

    You seem to care about this issue very much. Unfortunately, you also seem to respond quite negatively to any form of criticism to someone you view as irrefutable. In this case, James and others commenting here. Meanwhile, I probably don’t have very divergent views from your own. But rather than try to come to common ground, you seemingly purposefully misunderstand what I am saying and then refer to my understanding of this article and its framing in the research community as ‘ignorant’.

    So my last point would be to have some more patience. Actually read what others have written, whether they do or not agree with you. Even if they misunderstand your point at first, as I think I did in this case.

    Is that clearer?

  15. #15 robin
    April 4, 2011

    Hi James,
    No intention of offending but your picture that is displayed on this site is a horribly bad photo. You look like a creepy version of Mr. Spock. I recommend you change it.
    I have no objections to voice about your viewpoints but wish your article contained more novelty.

    bye