Page last updated at 22:39 GMT, Monday, 30 November 2009

Harrabin's Notes: Debating the IPCC

In his regular column, the BBC's environment analyst, Roger Harrabin, looks at how the affair of the stolen climate e-mails has sparked debate among some scientists about the body which peer reviews climate science.


Antarctic coast (AFP/Getty)
The affair of the stolen e-mails continues to divide opinion

The content of stolen e-mails from the Climatic Research Unit (CRU) at the University of East Anglia has prompted much discussion about the way peer-reviewed science is conducted.

But it is also raising questions among some scientists about the workings of the Intergovernmental Panel on Climate Change (IPCC).

The IPCC, steered by governments and drawing on the work of thousands of scientists and other experts, is the world's biggest peer-review body. It was formed because politicians needed definitive advice about the effects of greenhouse gases.

Most policymakers rely in large part on the IPCC's summary reports - so the summaries involve a battle of wills and opinions in the distillation of thousands of studies into climate change.

The last IPCC report, AR4, said the world's average temperature was certainly rising, and that the majority of the warming was more than 90% likely to be caused by emissions from humankind.

The CRU holds one of the key global data sets on temperature, so its data has helped underpin the IPCC's conclusions.

This report contributed to the current political consensus on the need for cuts in greenhouse gases (although not yet on the extent of the cuts).

A minority of sceptics who mistrust the evidence of recent warming are hoping their view will be corroborated by the inquiry into the stolen e-mails from CRU, in which some observers claim to see alleged signs of collusion among climate scientists.

Other scientists tell me they doubt the inquiry will affect the main course of scientific opinion, as the CRU temperature data set is very similar to the two other global sets, both in the US.

Demanding culture

A former IPCC lead author Mike Hulme says in an e-mail: "This (CRU) event might signal some re-structuring of scientific knowledge about climate change. It is possible that climate science has become too partisan, too centralised.

"The IPCC, through its tendency to politicise climate change science, has perhaps helped to foster a more authoritarian form of knowledge production - just at a time when a globalising and wired cosmopolitan culture is demanding of science something much more open and inclusive."

Some scientists regard Professor Hulme's statements as naive. They say governments and media respond to simple black-and-white messages, not nuanced explanations of complexity and uncertainty.

And some are not confident about alternative methods of assessing complex climate science.

John Schellnhuber - who was formerly co-director of the UK government-funded Tyndall Centre for Climate Change with Professor Hulme, asks how the public could be confident of authoritative information in a scenario where the IPCC were to be downgraded or even disbanded.

"I cannot see how, in practical terms, the entire scientific process can be turned into an online open-access enterprise," he says. "When it comes to transparency, inclusiveness and accountability, the IPCC is going further than any other policy-relevant scientific assessment.

"It would be interesting to learn whether Mike has any concrete ideas about how to replace the present mode (with) something definitely better."

He adds: "Having said this, I can only state that such a debate (about the IPCC) should not be prompted by a criminal act, breaching the constitutional rights of individual scientists."

Many scientists are likely to share Professor Schellnhuber's concern that Professor Hulme appears ready to share control over key scientific messages between government-appointed experts and self-appointed commentators on a world wide web.

'One voice'

John Houghton, chair of the science panel for the first IPCC report, says the current process could be improved, but should certainly not be scrapped in favour of something else.

"The IPCC has involved large numbers of scientists from many countries and disciplines. As a result, the world climate science community can to a substantial extent speak with one voice about the most important elements of the story.

"In other areas of science that are as diverse and uncertain as the climate, this convergence of informed opinion has not occurred.

"The IPCC has (also) brought about ownership of its conclusions by governments. Without this, governments' policies (with regards to) climate change would have been much more diverse and contradictory.

"I deny that this ownership has 'politicised' science. In fact, I believe that without it the science would have been much more politicised - by different groups of scientists serving groups with different and incompatible political agendas."

Professor Houghton said that in future it would be wise to offer the IPCC protection from harassment in its work. "IPCC meetings were open to all - including (representatives) from organisations such as the Global Climate Coalition whose clear agenda was to weaken our work and our conclusions.

"A particular way they continually did this was to publish selected provisional material from the IPCC process, for example draft chapters or contributions not meant for publication, and used this to discredit the IPCC and the process.

"For people being targeted, it is very difficult to be completely open when provisional material emerging during the process is being used as stick to beat the scientists with."

'Dominant model'

But Professor Hulme's comments have attracted some sympathy. The social scientist Dr Joe Smith, co-author of the Open University's climate change textbook, thinks the way climate science is conducted should be reappraised.

"The dominant model of science is one of aggressive individual or lab-based competition to break new ground and get the most convincing arguments supported by evidence," he told me.

"I think that that can be an unproductive form of 'knowledge generation'. One thing for sure is that it isn't designed to produce consensus around such a complex topic as climate change.

"So the IPCC has serious weaknesses - but it remains the most ambitious peer review process modern science has undertaken.

"The problems arise at the science-policy-media interface where these headlines are translated into a shorthand that there is a 'consensus' that 'the science is finished'.

"We should instead be continuing to engage (the wider public) in the idea that our best current understanding justifies very pacy and bold action on the basis of intelligent risk management."

Traditionally, peer review is the gold standard way to advance scientific knowledge. Though it has been described by some scientists as the "least worst" option.

Dr Smith's Open University colleague, Bob Spicer, who is a professor of earth sciences, told BBC News that the IPCC had done a "magnificent" job ofdistilling complex data. However, he added that the IPCC was too reliant on climate computer models and sometimes unresponsive to new data.

"The IPCC either needs to be terminated or it needs to evolve into something that provides summary data more quickly and to cast its net wider regarding relevant information.

"From the geological record, we already know that the current greenhouse gas equivalent has not been seen for more than 20 million years and we know what the world was like back then. The only thing we are unsure about is how long it will take for the Earth system to display those atmospheric changes as climate change phenomena."

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