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PARIS—The French Academy of Sciences finally produced a statement after a full day of debate on climate change Monday that had been shrouded in secrecy.

The debate followed a rumpus triggered by former research minister Claude Allègre and a handful of other scientists, who have contested the causes of climate change. The debate was ordered by Education and Research Minister Valérie Pécresse in April, after more than 600 scientists signed a petition alleging “denigration” by Allègre in his book L’imposure climatique (The Climate Fraud) and asking her to disavow it.

The statement appears to be in response to an outburst at the weekend from the French daily Le Monde.

In a front-page editorial, the paper lambasted a total blackout on the debate, the identity of the participants and their submissions. “What is it (that the Academy is) afraid of,” it asked. The secrecy “arouses suspicion.”

According to the statement, participants in the debate concluded that links between solar radiation variations and the earth’s orbit are not contested, but that the jury is still out on the importance of the impact of solar activity cycles.

Participants agreed, the statement said, there was a consensus on the direct impact of carbon dioxide and other greenhouse gases produced by human activity, but that their indirect effects are still controversial. One of the ways towards better understanding of climate patterns is the physiochemistry of clouds, they agreed.

As for who attended the debate, the mystery has been unravelled: 93 academy members, including Allègre, and 24 outsiders.

The reason that publicizing the details of the meeting was important, said Le Monde, was that pirated e-mails and errors in the last report of the Intergovernmental Panel on Climate Change (IPCC) already aroused “considerable mistrust.” But the reaction in the Anglo Saxon world, particularly from scientific institutions, was immediate, the newspaper noted. Five independent inquiries were conducted, none of which contested the IPCC’s main conclusions. “Climatologists were submitted to critical and rigorous questioning (sic!) … it would be normal for their detractors to have the same treatment,” it added.

The Academy plans to release a report on the meeting next month.

ScienceInsider, 21 September 2010

Scientific debate on climate [Débat scientifique sur le climat]

Institute de France & French Academy of Sciences, 20 September 2010

The French Academy of Sciences held a scientific debate on climate change on Monday, 20 September 2010, following a recommendation by the Minister of Higher Education and Research dated April 1, to “permit a civil contest of viewpoints and methods and to establish the current state of scientific knowledge on climate change.”

The debate, prepared by a steering committee, was based on forty papers written by members of the Academy (members, correspondents and foreign associates) and eminent personalities in the field of climate science at the invitation of the Academy. The meeting convened on 20 September, consisting of a multidisciplinary audience to help to apprehend the subject in its various components given that climate science is a particularly complex issue, due to the interaction of different disciplines involved.

The day was structured in four successive sessions. Each session, led by rapporteurs, began by presenting an overview. This presentation, followed systematically by reports and a general discussion, helped to distinguish between the scientifically acquired facts and the uncertainties as well as unresolved issues, with the aim of providing guidance for research priorities.

With regards to past climates, the effect of changes in solar insolation on the Earth’s orbit is undisputed. However, the importance of the impact of the cycles of solar activity remains disputed. The emergence over the last twenty years of reliable observational data, both from satellite observations or from large coordinated surface programmes, has turned climate change into scientifically valid research. Computer models, which are essential for the interpretation of data and future projections, have increased rapidly over this period. On greenhouse gas emissions, including CO2 emitted by human activities, while there is a consensus on their direct impact, the role of their indirect effects remains controversial. Among the identified mechanisms which are relevant for the understanding of climate change, the physical chemistry of clouds appears to be an important research areas which needs to be strengthened.

A report by the Academy on this debate, drawn from written and oral contributions, will be published by the end of October.

[transl. Philipp Mueller]