In the web site of the New Zealand Centre for Political Research, Fred Singer offers an excellent summary of the skeptics’ view of anthropogenic global warming. If you haven’t followed the issue in detail and want to review the basics, it’s a good place to start.
Singer makes one point that cannot be repeated too often: the AGW theory depends entirely on computer models, but we know for sure that those computer models are wrong. They do not accurately explain either the Earth’s climate history, or the present distribution of global temperatures. This simple diagram shows how the “fingerprint” predicted by AGW models fails to conform to observed atmospheric conditions; click to enlarge:
If you think about it, it is rather remarkable that Al Gore and his confederates have been able to stampede millions of voters, based on computer models that are indisputably contradicted by the facts.