“The warming in the climate system is unequivocal” and has been attributed to increased GHGs.
Working Group I of the Intergovernmental Panel on Climate Change (IPCC) firmly stands behind the conclusions of the IPCC Fourth Assessment Report, the community of researchers and its individuals providing the scientific basis, and the procedures of IPCC Assessments.
So begins a strong statement by the leaders of the IPCC working group focused on “The Physical Science Basis” of climate change and its causes (emphasis in original). Here’s the rest:
Comments on blogs and in the media about the contents of a large number of private emails stolen from the Climatic Research Unit at the University of East Anglia, United Kingdom, have questioned both the validity of the key findings of the IPCC’s Fourth Assessment Report (AR4) and the integrity of its authors. IPCC WGI condemns the illegal act which led to private emails being posted on the Internet and firmly stands by the findings of the AR4 and by the community of researchers worldwide whose professional standards and careful scientific work over many years have provided the basis for these conclusions.
The key finding of IPCC AR4, “The warming in the climate system is unequivocal [...] “, is based on measurements made by many independent institutions worldwide that demonstrate significant changes on land, in the atmosphere, the ocean and in the ice-covered areas of the Earth. Through further, independent scientific work involving statistical methods and a range of different climate models, these changes have been detected as significant deviations from natural climate variability and have been attributed to the increase of greenhouse gases.
The body of evidence is the result of the careful and painstaking work of hundreds of scientists worldwide. The internal consistency from multiple lines of evidence strongly supports the work of the scientific community, including those individuals singled out in these email exchanges, many of whom have dedicated their time and effort to develop these findings in teams of Lead Authors within the production of the series of IPCC Assessment Reports during the past 20 years.
The IPCC assessment process is designed to ensure consideration of all relevant scientific information from established journals with robust peer review processes, or from other sources which have undergone robust and independent peer review. The entire report writing process of the IPCC is subjected to extensive and repeated review by experts as well as by governments. Consequently, there is full opportunity for experts in the field to draw attention to any piece of published literature and its basic findings that would ensure inclusion of a wide range of views.
In compliance with the procedures of IPCC, the conclusions of AR4 have undergone scrutiny in the form of several stages of reviews by peers and governments, have been revised and refined to take into account these review comments, and have finally been approved word by word by the governments of the world1.Every layer in the process (including large author teams, extensive and multi-step reviews, independent monitoring of review compliance, and plenary approval by governments) plays a major role in keeping IPCC assessments comprehensive, unbiased, open to the identification of new relevant literature, and policy relevant but not policy prescriptive. Therefore, no individual scientist in the IPCC assessment process is in a position to change the conclusions, or to exclude relevant peer-reviewed papers and scientific work from an IPCC Assessment Report.
In conclusion, IPCC WGI firmly stands behind its unique procedures and behind the scientific community and their collective work which has been, and continues to be, the basis of unbiased, open and transparent assessments of the current knowledge on the climate system and its changes.
Prof. Thomas Stocker Prof. Qin Dahe
Co-Chair, Working Group I Co-Chair, Working Group I
1 The Working Group I Contribution to the IPCC Fourth Assessment Report, Climate Change 2007: The Physical Science Basis, the Drafts, Review Comments and Author Team Responses are available from the WGI website: http://www.ipcc-wg1.unibe.ch/publications/wg1-ar4/wg1-ar4.html