About a week ago in Shanghai, China, a group of several hundred scientists issued its report on climate change - a report given only once every five years. This "International Panel on Climate Change" is sponsored by the United Nations, and represents the best international effort at a non-partisan evaluation of global warming and other climate-change issues.

Their most important conclusion - the one I'm sure will generate the most controversy - is a projection of future global warming of between 2 and 10^oF over the next 100 years.

Now realize, this projection is based almost entirely on computer models, which are still far from perfect. That uncertainty is reflected in the huge range of the projection, from 2 to 10^oF. But the fact is that every one of a dozen or so different computer models that were used predicts at least some warming. This consistency, plus new observational evidence of warming in recent decades, has even some of the hardened global-warming skeptics now agreeing that if we continue to pump carbon dioxide into the air, the world will warm. The main questions now are how quickly and how much?