There are two scientific phenomena that are routinely mixed into one by sloppy media reporting--global warming and the expansion of "greenhouse gasses." The world is getting warmer, we are told, and the reason is all the carbon dioxide in the atmosphere. Rarely is it said that the first phenomenon is a fact and the second is an unproven and perhaps unprovable theory. The world has been warming for two centuries, for reasons no one seems to understand fully.
It has been colder before, most notably in the so-called "little ice age" from the late middle ages to about 1750. The paintings we see of Dutch kids skiing on the canals are from that era, as well as photos of baseball games on the Lincoln Park Lagoon while the world was warming up again. No one knows why these cycles occur. There are lots of theories (volcano eruptions and cycles in the sun for example) but nothing solidly established. However, the world has been warming for the last 200 years more or less (with some intermittent cooling, especially during the 1930s and '40s). Most of the warming occurred before the use of fossil fuel and hence cannot be attributed to carbon dioxide.
In scientific discourse one cannot separate the independent contributions to a phenomenon of two possible causes, unless one can hold them constant in comparison one with another. Since we do not understand the cause of the natural warming, we are unable to say what proportion, if any, is the result of the added impact of human-created warming. It is possible (though perhaps unlikely) that one could end all the carbon dioxide emissions tomorrow and the world would keep on getting warmer--North Mayo would once again produce two crops a year.
It is certainly prudent to diminish carbon dioxide emissions, because there is a chance the "greenhouse gasses" might be aggravating a natural process that could be dangerous. One need not be absolutely certain as a precondition for prudence and wisdom. Finally, however, no useful purpose is served by media reports intending to stir up hysteria and rage at the United States.
While Mr. Bush is clearly obsessed with energy and energy companies and is not especially concerned about the environment, it is hardly fair to blame him for "scuttling" the Kyoto treaty when his predecessor had no intention of abiding by it. If he were not so clumsy, he would have left the moribund treaty alone and announced programs for decreasing carbon dioxide emissions in this country, including constraints on the SUVs. Instead, he has gone at the problem the other way around. He has thus played into the hands of the radical ideologues who are using climate change to impose their moral opposition to fossil fuel on all the world.