This is the third time in as many weeks that serious doubts have been raised over the IPCC’s conclusions on climate change. Two weeks ago, after reports in London’s The Sunday Times and The Australian, the panel was forced to retract a warning that climate change was likely to melt the Himalayan glaciers by 2035. That warning was also based on claims in a WWF report.
The IPCC has been put on the defensive as well over its claims that climate change may be increasing the severity and frequency of natural disasters such as hurricanes and floods.
IPCC chairman Rajendra Pachauri was fighting to keep his job over the weekend after a barrage of criticism. Scientists fear the controversies will be used by climate change sceptics to sway public opinion to ignore global warming – even though the fundamental science, that greenhouse gases can heat the world, remains strong.
The latest controversy originates in a report, A Global Review of Forest Fires, that WWF published in 2000. It was commissioned from Andrew Rowell, a freelance journalist and green campaigner who has worked for Greenpeace, Friends of the Earth and anti-smoking organisations. The second author was Peter Moore, a campaigner and policy analyst with WWF.
In their report, they suggested that “up to 40 per cent of Brazilian rainforest was extremely sensitive to small reductions in the amount of rainfall” but made clear this was because drier forests were more likely to catch fire.
The IPCC report picked up this reference but expanded it to cover the whole Amazon. It also suggested that a slight reduction in rainfall would kill many trees directly, not just by contributing to more fires. The IPCC said: “Up to 40 per cent of the Amazonian forests could react drastically to even a slight reduction in precipitation; this means the tropical vegetation, hydrology and climate system in South America could change very rapidly to another steady state.
“It is more probable that forests will be replaced by ecosystems that have more resistance to multiple stresses caused by temperature increase, droughts and fires, such as tropical savannas.”
Simon Lewis, a Royal Society research fellow at Leeds University who specialises in tropical forest ecology, described the section of the report by Rowell and Moore predicting the potential destruction of large swaths of the Amazon as “a mess”.
“The Nature paper is about the interactions of logging damage, fire and periodic droughts, all extremely important in understanding the vulnerability of Amazon forest to drought, but is not related to the vulnerability of these forests to reductions in rainfall,” he said.
He believes the IPCC should ban the use of reports from campaign groups.
“In my opinion, the Rowell and Moore report should not have been cited; it isn’t sufficient evidence to back any claim at all, as it contains no primary research data,” Mr Lewis said. The WWF said it prided itself on the accuracy of its reports and was investigating the latest concern. “We have a team of people looking at this internationally,” said Keith Allott, its climate change campaigner.
The Amazon constantly undergoes huge changes because of natural variability in the weather, aside from damage caused by human factors such as logging and agricultural clearance.
Spotting the additional impact of global warming against such a changing background is difficult, especially when the world has so far warmed by about 0.7C since the 18th century.
The Sunday Times