“Amazongate is only an error of improper referencing, the actual science behind the key claim is sound”. This is the message that has been hammered home repeatedly by experts involved in Amazon forest research. In their press releases, letters of complaint and blog posts, they have refused to concede something might be wrong with the report, and argued that journalists should have performed in-depth research before bringing any disrepute to the IPCC.
Even as we search high and low only to conclude that the exact claim does not appear to supported by the literature available to date, another argument has been advanced simultaneously in defence of the IPCC. It says that the scientific evidence, the crucial pieces that go to make up this claim, bizarre though it might be, lie in many different papers. The IPCC report just brings them together – it paints an integrated picture of the trouble the Amazon region is in. So the defense of the IPCC is bi-layered. The science behind the imminent catastrophic destruction of the Amazon forests is true, and the IPCC makes a synthetic judgement to this effect. The only flaw is therefore one of citations.
The IPCC makes available its first order and second order drafts and reviewer comments. The question is: do these drafts and comments carry any indications or clues to the scientific summation and thinking process that is alleged to have taken place?
Genealogy of the IPCC Amazon rainforest ’40%’ claim.
Let use first examine the passage in question through the drafts, in sequence.
The first order draft (FOD) text
Forty percent of the Amazonian forests could react sensibly to a slight reduction of precipitation; this could mean that the tropical vegetation, hydrology and climate system in South America, may change very rapidly to another steady state not necessarily producing gradual changes between the actual and the future situation (Rowell and Moore, 2000).
(Available at http://ipcc-wg2.gov/AR4/FOD/Ch13_FOD.pdf, page 25, )
Reviewer Comments on the first order draft
By December of 2005, reviewer comments on the first order draft were made available to authors. This document reveals an illuminating comment from Jos Barlow, then at the University of East Anglia (yes, the UEA). Referring to the paragraph by its first line, he writes:
Forests that burn once become more vulnerable to a recurrent and more severe fire. These fire related positive feedbacks can shift relatively prisine tropical forest to bamboo dominated scrub savannahs in just 12 years (e.g. Cochrane et al. 1999, Barlow and Peres 2004. Cochrane (2001 Environment 43, 28-38) estimates that 259,000km2 of Amazonian forests are vulnerable to such a recurrent fires, which have disastrous consequences for biodiversity (Barlow and Peres 2004). Such drastic changes deserve a mention in this report.
(Available at http://ipcc-wg2.gov/AR4/FOD_COMMS/Ch13_FOD_comments.pdf, Page 113)
The authors’ respond that the comment is ‘accepted’.
The second order draft (SOD) text
Forty percent of the Amazonian forest could react drastically even to a slight reduction of precipitation; this means that the tropical vegetation, hydrology and climate system in South America, could change very rapidly to another steady state no necessarily producing gradual changes between the actual and the future situation (Rowell and More, 2000).
(Available at http://ipcc-wg2.gov/AR4/SOD/Ch13.pdf, page 23)
The final IPCC Chapter 13 text
Up to 40% of the Amazonian forests could react drastically to even a slight reduction in precipitation; this means that the tropical vegetation, hydrology and climate system in South America could change very rapidly to another steady state, not necessarily producing gradual changes between the current and the future situation (Rowell and Moore, 2000).
Compare the first, second and final versions - the significant change, really is just the addition of the word ‘drastic’. If it was indeed accepted, the authors seem to have incorporated Barlow’s suggestion about forest fires into a single muddled, exaggerated sentence about precipitation effects. In the FOD, the authors appear to use “sensibly”, to mean something that is appreciable or measurable. This, suddenly changes to ‘drastically’, in the second draft.
This is then, the change that results in the ‘oversell’ of the Amazon precipitation sensitivity. The word ‘drastic’ ratchets up the rhetorical implication of the sentence, but the same WWF reference remains cited.
More importantly, contrary to what many have suggested, it does not seem, that a statement was formulated assessing all available literature at the time. The sentence in question remained virtually unchanged through the drafts (except for the ‘drastic’ addition), it referred to the same WWF report through three different versions.
Several experts have offered a stream of citations supporting this badly written statement. If eminent scientists believe that their many references to peer-reviewed papers support this overstretched IPCC judgement – with the above facts in mind, a call must go out for the IPCC to make an official correction and rewrite the passage accordingly. just as it did with the Himalayan glaciers. In an official document of this stature, one hopes that a key passage such as this, will accurately match the literature it is supposedly substantiated by.
The IPCC claim is tri-fold: first, that a large proportion (40%) of the entire Amazon forest will be ‘affected’, second, that the ‘reaction’ would be drastic, as in sudden, and severe, and third, that this drastic reaction’ could be caused by ‘even’ a ‘slight’ reduction of rainfall, not drought-type conditions. Making exaggerated claims and propping them up, after the fact only diminishes trust in the process. Calling for a correction would have been better than blaming journalists and bloggers, without whom, the experts and the much-vaunted IPCC peer-review did not even recognize these errors. The reviewers comments stands a testimony to this fact.
Anthony Watts links here,with an excerpt going straight to the heart of the matter
Dan Nepstad posts in the same thread, in the comments section.