ADDENDUM JUL 13: Christopher Booker has managed to trace the 40% claim to a deleted web page. “Neither WWF nor Woods Hole come well out of this story“. Definitely, they do not. See also EU Referendum.
ADDENDUM FEB 15: Daniel Nepstad has posted a statement endorsing “the correctness of the IPCC’s (AR4) statement on Amazon forest susceptibility to rainfall reduction” (link fixed on JUL 13). But Nepstad makes several references to 2004 and 2007 articles whose existence the IPCC authors were not obviously aware of. If the IPCC has been right for the wrong reasons, we can state it has been wrong: because it cannot simply be a matter of having it right by pure chance.
(I have posted a version of the below as a comment at WUWT, concerning James Delingpole’s “After Climategate, Pachaurigate and Glaciergate: Amazongate” and in the response to the following comment by an “Icarus” (Jan 25, 14:19:23):
It appears that the 40% figure references this passage in the WWF/IUCN report:
“Up to 40% of the Brazilian forest is extremely sensitive to small reductions in the amount of rainfall. In the 1998 dry season, some 270,000 sq. km of forest became vulnerable to fire, due to completely depleted plant-available water stored in the upper five metres of soil. A further 360,000 sq. km of forest had only 250 mm of plant-available soil water left.”
This passage references a peer-reviewed article in Nature:
46 D. C. Nepstad, A. Veríssimo, A. Alencar, C. Nobre, E. Lima, P. Lefebvre, P. Schlesinger, C. Potter, P. Mountinho, E. Mendoza, M. Cochrane, V. Brooks, Large-scale Impoverishment of Amazonian Forests by Logging and Fire, Nature, 1999, Vo l 398, 8 April, pp505
Unfortunately I don’t have access to the full article but to call this reference “a complete load of porkies” seems a bit unjustified, unless it can be shown that Rowell and Moore completely misrepresent the Nature article (which of course *is* written by Amazonian specialists).
The expression “a complete load of porkies” for what ended up in the IPCC AR4 WG-II Chapter 13, seems a bit justified indeed.
First of all it should not be up to the reader to dig down in the IPCC references until anything peer-reviewed is finally found. If Nepstad et al 1999 were the primary source for the “Up to 40%” claim, that article should have been used, stated and referenced as such, no matter what Rowell and Moore understood of it.
Secondly, the IPCC AR4 WG-II Chapter 13 makes no mention of Nepstad et al 1999. As far as I can see, the Nepstad et al 1999 article is only used in AR4 in the IPCC AR4 WG-II Chapter 4:
Recently observed moderate climatic changes have induced forest productivity gains globally (reviewed in Boisvenue and Running, 2006) and possibly enhanced carbon sequestration, especially in tropical forests (Baker et al., 2004; Lewis et al., 2004a, 2004b; Malhi and Phillips, 2004; Phillips et al., 2004), where these are not reduced by water limitations (e.g., Boisvenue and Running, 2006) or offset by deforestation or novel fire regimes (Nepstad et al., 1999, 2004; Alencar et al., 2006) or by hotter and drier summers at mid- and high latitudes (Angert et al., 2005)
in some tropical and sub-tropical regions, notably South-East Asia and similarly the Amazon (e.g., Nepstad et al., 1999), deforestation rates are still high
You may note that in both cases Nepstad et al 1999 is used to mention deforestation (something one might expect out of an article titled Large-scale Impoverishment of Amazonian Forests by Logging and Fire).
The abstract of that article is particularly terse on Nature.com:
Amazonian deforestation rates are used to determine human effects on the global carbon cycle and to measure Brazil’s progress in curbing forest impoverishment,,. But this widely used measure of tropical land use tells only part of the story..
For some reason, there is a longer version on Mendeley.com:
Amazonian deforestation rates are used to determine human effects on the global carbon cycle(1-3) and to measure Brazil’s progress in curbing forest impoverishment(1,4,5). But this widely used measure of tropical land use tells only part of the story. Here we present field surveys of wood mills and forest burning across Brazilian Amazonia which show that logging crews severely damage 10,000 to 15,000 km(2) yr(-1) of forest that are not included in deforestation mapping programmes. Moreover, we find that surface fires burn additional large areas of standing forest, the destruction of which is normally not documented. Forest impoverishment due to such fires may increase dramatically when severe droughts provoke forest leaf-shedding and greater flammability; our regional water-balance model indicates that an estimated 270,000 km(2) of forest became vulnerable to fire in the 1998 dry season. Overall, we find that present estimates of annual deforestation for Brazilian Amazonia capture less than half of the forest area that is impoverished each year, and even less during; years of severe drought. Both logging and fire increase forest vulnerability to future burning(6,7) and release forest carbon stocks to the atmosphere, potentially doubling net carbon emissions from regional land-use during severe El Nino episodes. If this forest impoverishment is to be controlled, then logging activities need to be restricted or replaced with low-impact timber harvest techniques, and more effective strategies to prevent accidental forest fires need to be implemented.
It is hard not to notice that Nepstad et al 1999 were concerned about deforestation and fires possibly exarcebated by severe droughts, whilst Rowell and Moore, and the IPCC authors and reviewers, completely turned the cards around, pushing hard on the climatic side first.
That is not the first time I have seen “Chinese whispers” at play in the IPCC AR4…