In my more than 60 years as a member of the American scientific community, including service as president of both the National Academy of Sciences and the American Physical Society, I have never witnessed a more disturbing corruption of the peer-review process than the events that led to this IPCC report.

Individual curiosity, often working without practical ends in mind, has always been a driving force for innovation.

It is one thing to impose drastic measures and harsh economic penalties when an environmental problem is clear-cut and severe....It is foolish to do so when the problem is largely hypothetical and not substantiated by observations....we do not currently have any convincing evidence or observations of significant climate change from other than natural causes.

But more than 15 sections in Chapter 8 of the report-the key chapter setting out the scientific evidence for and against a human influence over the climate-were changed or deleted after the scientist charged with examining this question had accepted the supposedly final text.

In my more than 60 years as a member of the American scientific community, including service as president of both the National Academy of Sciences and the American Physical Society, I have never witnessed a more disturbing corruption of the peer-review process than the events that led to this IPCC report.

The trouble is that you won't get the scientists to agree on a course of action. It is almost instinctive in science to accept contrary views, because disagreeing gives you guidance to experimental tests of ideas - your own and those offered by others...

This treaty [Kyoto] is, in our opinion, based upon flawed ideas. Research data on climate change do not show that human use of hydrocarbons is harmful. To the contrary, there is good evidence that increased atmospheric carbon dioxide is environmentally helpful...agreement would have very negative effects upon the technology of nations throughout the world, especially those that are currently attempting to lift from poverty and provide opportunities to the over 4 billion people in technologically underdeveloped countries.