Sir

Your News story “US posts sensitive climate report for public comment” (Nature 441, 6–7; 2006) implies that the United States has departed from its traditional approach in reviewing draft reports from the Intergovernmental Panel on Climate Change (IPCC). In fact, US procedures, first published in the Federal Register in 1995, reflect our longstanding commitment to open IPCC reviews.

Under the 1995 procedures, we provided paper copies of IPCC draft reports to any individual upon request. In 2000, individuals were also asked to provide information on their “qualifications and general area of expertise ... to review specific parts of the report”, although to the best of my knowledge drafts were made available to all who submitted requests. Since September 2004, after legal counsel advised that requiring individuals to provide such information was inconsistent with federal information-dissemination guidelines, we have made IPCC drafts available on the US Climate Change Science Program website (http://www.climatescience.gov/Library/ipcc); this prominently displays IPCC instructions that drafts not be cited, quoted or distributed. As far as we were aware, everyone accessing this website had abided by the IPCC instructions, until Nature published elements of the Fourth Assessment Report.

Our approach reflects the view that it is neither possible nor appropriate for the government to decide which individuals are expert enough to review the report. Comments on the draft will be reviewed on their merits by prominent scientists during both US and international IPCC reviews. To ensure objectivity, submitted comments will be supplied to federal programme managers and scientists without attribution and then evaluated on scientific and technical grounds before being sent to the IPCC.

The United States is committed to an effective review of the IPCC Fourth Assessment Report, and we intend to provide comments reflecting the extensive expertise of the US scientific community.