Amazongate: The Missing Evidence

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UK Telegraph:

Amazongate: the missing evidence
The story of the IPCC's claims about threats to the Amazon rainforest takes another bizarre turn, says Christopher Booker

By Christopher Booker
Published: 6:22PM BST 26 Jun 2010


Information about logging and fire risks in the Amazon ended up in the IPCC?s 2007 report on global warming Photo: Sipa Press/Rex Features

Last week the beleaguered global warming lobby was exulting over what it took to be the best news it has had in a long time. A serious allegation, which last January rocked the authority of the UN’s Intergovernmental Panel on Climate Change, was “corrected” as untrue by The Sunday Times, the newspaper which most prominently reported it. The reputation of the IPCC, it seemed, had been triumphantly vindicated. The growing tide of scepticism over climate change had at last been reversed. But this episode leaves many questions unanswered.

The “correction”, gleefully quoted by everyone from the WWF and The New York Times to The Guardian’s George Monbiot related to what was known as “Amazongate”. This was one of the series of controversies which exploded round the IPCC last winter, when it was shown that many of the high-profile claims made in its 2007 report had been based on material produced by environmental activists and campaigning groups rather than on proper, peer-reviewed scientific evidence.

One example, also reported in The Sunday Telegraph, was the IPCC’s much-publicised claim that climate change, leading to a reduction in rainfall, was threatening the survival of “up to 40 per cent” of the Amazon rainforest. The only source the IPCC could cite for this in its report was a document from the environmental advocacy group WWF. But last week The Sunday Times, in its prominent “correction” to its own story, conceded that the IPCC’s claim was “supported by peer-reviewed scientific evidence” after all. Not identified, however, was the nature of this peer-reviewed evidence. Where is it?

The story of “Amazon-gate” has unfolded through three stages. Step one was the passage in the IPCC report almost identical to one made in a non-peer-reviewed WWF paper of 2000 on forest fires in the Amazon. Specifically the IPCC stated that “up to 40 per cent of the Amazonian forests could react drastically to only a slight reduction in precipitation”. But the only source the WWF in turn had been able to cite to support this was a paper published in Nature in 1999, from a team led by Dr Daniel Nepstad, formerly employed by the WWF but now the “senior scientist” with another advocacy group closely linked to the WWF, the Woods Hole Research Center. Certainly Nepstad’s paper was peer-reviewed: however its subject was not climate change but the impact on the Amazon rainforest of “logging and fire”. It found that “logging companies in Amazonia kill or damage 10-40 per cent of the living biomass of forests”. This had nothing whatever to do with global warming but was cited as the origin of that “up to 40 per cent” figure later used by the WWF and the IPCC.

Step two, when all this was reported last January, was a disclaimer from the WWF, emphasising that its 2000 report did “not say that 40 per cent of the Amazon forest is at risk from climate change”. But it went on to say that the real source for its 2000 paper (which had been “mistakenly omitted”) was another paper, “Fire in the Amazon”. This was also written by Dr Nepstad, as head of yet another advocacy group linked to Woods Hole, the Amazon Environmental Research Institute. Although it was now being suggested that this paper should have been cited as the original source for the IPCC’s claim, it too was not peer-reviewed. Thus, twice over, the IPCC’s claim appears to rest both on non-peer-reviewed science and on studies not related to global warming at all.

So great was the IPCC’s embarrassment over these revelations that the story moved to a third stage. Various scientists, led by Dr Nepstad, suggested further studies which might justify the claim. But an exhaustive trawl through all the scientific literature on this subject by my colleague Dr Richard North (who was responsible for uncovering “Amazongate” in the first place), has been unable to find a single study which confirms the specific claim made by the IPCC’s 2007 report. If one exists we would very much like to see it.
There are several studies based on computer models which attempt to estimate the possible impact of climate change on the Amazon rainforest, but none of these have so far supported that 40 per cent figure. Other researchers in turn have been highly critical of these models, suggesting that they are too crude to replicate the complex workings of the Amazonian climate system and that all observed evidence indicates that the forest is much more resilient to climate fluctuations than the alarmists would have us believe.

Nothing did more to excite attention over the effect of climate change on the rainforest than the exceptional drought of 2005, just when the IPCC’s 2007 report was being compiled. Since then, however, abnormally heavy rainfall in the region has brought disastrous floods to Brazil, both last year and again last week.

In other words there is a real mystery here. Nothing so far made public seems to justify an assertion that the IPCC’s specific claim is “supported by peer-reviewed scientific evidence”. In view of all the controversy this issue has aroused over several months, it might seem odd that, if such evidence exists, it hasn’t been produced before. Is it not now a matter of considerable public interest that we should be told what it is?