Both sides wrong in warming argument

There have been several letters on global warming in this paper recently, most responding to Dan Kimber's July 28 column on the matter ("Science vs. Politics," Education Matters).

I am not a climatologist, but as a scientist working on a weather satellite, I do work with them. There has been serious misrepresentation of their research on both sides of this debate.

The global warming issue is more than simply answering the question "is it real?" There are actually four questions to answer. First, has the earth on average become warmer over the last century? Second, is it caused by human activity? Third, is it caused by natural effects? Fourth, if the earth is warming, will this be catastrophic or beneficial to humans or other living things?

Regarding the first three questions, there is, in fact, almost universal agreement among climatologists that the answer is at least a qualified "yes" for each. Some on the political left, however, have tried to use this agreement to give the false impression that there is also universal agreement on the fourth question. Ray Shelton, on Aug. 10 ("The myth of global warming," Community Commentary), cites the "Oregon Petition," signed by 17,000 scientists disputing predictions of catastrophic global warming, but this petition only addresses the fourth question.

On the political right some have tried to deny that man-made global warming is occurring at all. Shelton calls it a myth and says that climatologists are simply guessing. In actuality, their analysis is performed using some of the most powerful computers on earth. Of course, in all scientific study there are assumptions and estimates that must be made, but to discount this as a "we guess" shows no respect for those who devote their life's work to this effort.

A Mailbag letter by Bob Gregg ("'Global warming' depends on where") on Wednesday lists many examples of local temperatures that have run counter to the global warming trend, and indeed, there are many places where this is true, but global warming regards only the average temperature, taken over the entire earth over many years, and so local trends are irrelevant.