St. Maarten Private Eye

Caribdude,
My credentials first - I am a PhD environmental scientist and have been in the business for over 25 years. I have spent 10 years in climatology, including climate modeling, model evaluation, etc. I am a skeptic of CO2 being a primary forcing of AGW (anthropogenic global warming). My models can predict with good accuracy the temperature variations over the last 2,000+ years using solar radiation and volcanic activity as the primary forcings. This includes the medieval warming period and the little ice age. In my opinion, this is not settled science.
First off, the climate of earth has been changing constantly since the earth was formed. We are going to have climate in the future - there is little that we can do about it. What we can do is deal with Anthropogenic contributions.
The forecasts about global warming are based upon computer modeling (the IPCC used three models primarily). The summary was written by politicians with the final report to follow months later (actually there are four groups that wrote key sections).
The reports in 1990, 1995 and 2001 had been progressively more alarmist. the report this year has toned down much of the rhetoric. Although CO2 is increasing, global temperatures haven't.
The UN’s (you know, the organization that can't organize a dog fight) 2001 IPCC report shows that our greenhouse-gas emissions since 1750 had caused a “radiative forcing” of 2.43 watts per square meter. Other effects on climate were shown as broadly self-cancelling. In the current draft, the UN has cut its estimate of our net effect on climate by more than a third, to 1.6 watts per square meter. It now thinks pollutant particles reflecting sunlight back to space have a very strong cooling effect. Dr. James Hansen, the father of global warming, has started to believe that the impacts of CO2 are much less than originally thought.
Global change modeling can be characterized into a number of categories. The models that the IPCC relies on are not predictive models, but quality assurance models. In short, they are not reliable for predicting future events.
I am not going to refute or argue the many points that I disagree with on AGW. However, for those wanting to read about scientific work that doesn't get into the press very often, see:
Co2 Science
Icecap
Climate Science
The last URL is technical in nature. If you read the comments, you can usually figure out what the significance of the topic is. Icecap is more for the layman.

As a final note for now, how do the global warming believers explain the following taken from Icecap: The most reliable global, regional and local temperature records from around the world display no distinguishable trend up or down over the past century. The last peak temperatures were around 1940 and 1998, with troughs of low temperature around 1910 and 1970. During this period the CO2 concentrations were increasing. Between 1940 and 1975, the temperatures were dropping. Believe what you may, but this is not settled science.