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About 15,000 US science graduates, including 6,000 PhDs, have signed a petition that rejects the Kyoto agreement on global warming and argues that increases in carbon dioxide levels benefit Earth, according to the petition's organizers.

The petition is likely to be released by the George Marshall Institute in Washington DC in the near future, and opponents of the Kyoto agreement are expected to use it to back up their arguments about a lack of scientific consensus on the issue.

But the mass-mailing of the petition to scientists — accompanied by a lengthy review article that had not been peer-reviewed or published — has angered some of those who believe that carbon dioxide emissions are a serious problem. They also argue that the number of signatories is a relatively small proportion of those who were mailed.

“Virtually every scientist in every field got it,” says Robert Park, a professor of physics at the University of Maryland at College Park and spokesman for the American Physical Society. “That's a big mailing.” According to the National Science Foundation, there are more than half a million science or engineering PhDs in the United States, and ten million individuals with first degrees in science or engineering.

Arthur Robinson, president of the Oregon Institute of Science and Medicine, the small, privately funded institute that circulated the petition, declines to say how many copies were sent out. “We're not willing to have our opponents attack us with that number, and say that the rest of the recipients are against us,” he says, adding that the response was “outstanding” for a direct mail shot.

The Union of Concerned Scientists has branded the exercise as “a deliberate attempt to deceive the scientific community with misinformation on the subject of climate change”. And prominent members of the National Academy of Sciences, whose past-president, Frederick Seitz, wrote a cover letter for the mailing, are also upset, according to a spokesperson for the academy, partly because the article in the mailing looks exactly like a paper from the Proceedings of the National Academy of Sciences (PNAS).

Robinson, a biochemist and former close associate of Linus Pauling, co-authored the article with Sallie Baliunas, a planetary scientist at Harvard University and noted global warming sceptic, and with Robinson's son Zachary, who has just obtained his bachelor's degree from Oregon State University. The article, “Environmental effects of increased atmospheric carbon dioxide”, argues that the release of more carbon dioxide “will help to maintain and improve the health, longevity, prosperity and productivity of all people”.

“I really don't think we are deceiving people,” says Robinson. “I have published in the past in PNAS and I chose the format because I liked it. I wanted the format that scientists are used to reading.” Robinson says the paper is now being submitted to an undisclosed journal for publication.