Over on Yale E360, IPCC chair Rajendra Pachauri responds to the allegations of inaccuracies in the panel’s 2007 assessment report. Specifically, he addresses the accusations of error referred to (somewhat absurdly) as Glaciergate, Amazongate and Africagate. Pachauri – who has recently been cleared of allegations of financial irregularity – writes:
AR4 stated that the Himalayan glaciers could melt by 2035. This figure was incorrect and unfortunately based on a single unsubstantiated source. When this error came to light, the IPCC expressed its regret and noted it on its website. The error was contained in a single sentence and in one graphic representation out of AR4’s nearly 3,000 pages.
It did not appear in any of the IPCC summaries relied on by policymakers. In those summaries, the language states: “Glacier melt in the Himalayas is projected to increase flooding, and rock avalanches from destabilized slopes, and to affect water resources within the next two to three decades. This will be followed by decreased river flows as the glaciers recede.” This statement remains valid, as does the fact that widespread loss of glacial mass and reduction in snow cover will accelerate throughout the 21st century largely as a result of human activities that are warming our Earth’s atmosphere.
The IPCC was accused of exaggerating the extent to which the Amazon rainforest could be damaged by a decrease in rainfall. The paragraph in question correctly stated: “By mid-century, increases in temperature and associated decreases in soil water are projected to lead to gradual replacement of tropical forest by savanna in eastern Amazonia. Semi-arid vegetation will tend to be replaced by arid-land vegetation.”
This was a classic case in which the controversy was initiated not by scientists but by the mainstream media, which badly distorted the facts. Blogs and other articles argued incorrectly that a report, the “Global Review of Forest Fires,” should not have been cited as a reference, because
it was published by two non-governmental organizations. But the paragraph in question accurately presented results in the literature it cited. It was a small part of a long, well-referenced discussion of Amazonian risk. Although the “Global Review of Forest Fires” was not a peer-reviewed document, it nevertheless was an important compilation, assembling information from more than 100 sources, including peer-reviewed scientific papers and reports from governments and non-governmental organizations, as well as news articles.
On March 18, 18 respected rainforest scientists from Brazil, the U.S., and the U.K. issued a lengthy statement reaffirming the IPCC’s conclusion that up to 40 percent of the Amazon rainforest is at risk because of climate change. Their statement can found online.
Another alleged exaggeration of AR4 was that climate change could reduce crop yields in parts of Africa by up to 50 percent. The only concern here was that in condensing the material from the underlying Working Group II Summary for Policymakers for the Synthesis Reports, the important qualifying phrase “by climate variability and change” was omitted from a statement that read: “Agricultural production, including access to food, in many African countries is projected to be severely compromised.” This is no way diminished or altered the scientific basis or the policy relevance of the statement included in the synthesis report.