Published online 2 February 2010 | Nature 463, 596-597 (2010) | doi:10.1038/463596a

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IPCC flooded by criticism

Climate body slammed for errors and potential conflicts of interest.

The group’s next assessment will focus on the socio-economic effects of climate change.Beawiharta/REUTERS

Just over two years after winning the Nobel Peace Prize, the United Nations panel on climate change is undergoing a period of soul-searching.

The Intergovernmental Panel on Climate Change (IPCC) has always been a target for climate-change sceptics. In recent weeks, however, criticism has mounted and the panel admitted to a glaring error in its last comprehensive report, released in 2007, which says that Himalayan glaciers are likely to melt completely by 2035 (see Nature 463, 276–277; 2010). On top of that, its chairman, Rajendra Pachauri, is under pressure to resign because the institute he directs, the Energy and Resources Institute in New Delhi, has ties with companies that could benefit from climate policies.

In response, many climate scientists — including a number already involved in the next IPCC assessment, due in 2014 — have been putting forward ideas about how the panel might reconsider its rules and procedures. The hope is to reduce errors in the final product and create policies on potential conflicts of interest.

The IPCC had already planned for the next assessment report, known as AR5, to follow the same basic outline as its last one, with three working groups to tackle three areas of interest: the physical science of climate change, the impacts such change is likely to have and how these might be mitigated. There are two review editors for each chapter and the whole thing will be checked before publication, first by expert reviewers and then by governments. Governments and scientific organizations around the world are looking for people to serve as authors and reviewers; nominations are due by 12 March.

In addition to the Himalayan glacier error, the panel has been accused of saying that climate change has caused an increase in economic losses from extreme weather; the IPCC last week refuted that allegation, saying that a study in one part of the report had been taken out of context. Others have challenged the source of an estimate contained in the report that up to 40% of the Amazonian rainforest "could react drastically" to reduced rainfall.

Those involved in the process say it works well. "The IPCC is a bottom-up process in which hundreds of scientists dedicate their time on a voluntary, unpaid basis to provide an assessment of climate science," says Thomas Stocker of the University of Bern, co-chair of AR5's first working group, on the physical science of climate change. "This model has been extremely successful."

"In my view, the IPCC's institutional structures and processes are very strong," adds Pachauri, who says he will not step down as chairman. "What we have to do is to ensure full and complete compliance with the procedures while preparing IPCC's assessment reports."

“I have no doubt that similar errors could be found in earlier IPCC reports.”


Others say there is room for improvement. Kevin Trenberth of the National Center for Atmospheric Research in Boulder, Colorado, a lead author of the 2007 report, says that critics have grossly underestimated the rigour of the IPCC review process. However, he does say that the reports from the three working groups could be better coordinated.

The reports are done in parallel, even though the impacts working group is supposed to build on the results of the science working group. "Often a separate assessment is done in the [impacts] working group, and results can differ as the expertise is quite different," Trenberth says.

The 2007 error on Himalayan glaciers reflected the lack of coordination: it appeared in the impacts report even though the science group had not found any peer-reviewed study that reached this conclusion.

Coordination will matter even more for the next assessment, which was set up to focus more heavily on assessing socio-economic aspects of climate change and its implications for sustainable development. As such, issues including water availability, ice-sheet shrinkage and sea level rise are likely to get more scrutiny — and will require more consistent treatment across working groups. The suggested approach, adopted in October 2009, is for each working group to assign a small group of authors the task of coordinating with their counterparts in the other working groups.

However, critics also say that, in the last round, IPCC lead authors ignored comments from reviewers and governments questioning the validity of the glacier claim. For instance, David Saltz of Ben-Gurion University of the Negev in Israel questioned why one sentence in the report said that the Himalayan glaciers would disappear completely, whereas the next said that they would shrink to 100,000 square kilometres. A later note from the writing team said only: "Missed to clarify this one".

Some errors will inevitably creep in, says Jürgen Willebrand, an oceanographer at the Leibniz Institute of Marine Sciences in Kiel, Germany, and a coordinating lead author of the 2007 report. "IPCC reports are written by humans," he says. "I have no doubt that similar errors could be found in earlier IPCC reports, but nobody has bothered to look in detail because at the time of these reports the IPCC was less visible to society, politics and media." But he says the IPCC should have a more formal process for ensuring each flagged error is dealt with promptly.

He also calls for the IPCC to develop a policy on potential conflicts of interest.

Andrew Weaver, a climate scientist at the University of Victoria in Canada, wants more far-reaching procedural changes. Rather than carrying out "monolithic" assessments, he says, the IPCC should focus on more specific problems such as describing emissions pathways required to avoid a given temperature rise. The distinction between different working groups should also be revised, he suggests.

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"If you have diverse interdisciplinary teams working on specific problems, then you can have scientists, economists and engineers all looking at a particular problem through the lens of their expertise," he says. "There is so much science out there to assess; it needs to be better focused."

Any such structural changes — or any change in Pachauri's leadership of the group — would need to be approved in the plenary session of the IPCC panel. The next such meeting will take place in October in Busan, South Korea. 

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