To the editor:

George Gurley’s column published July 2 deals mostly with the “fundamentalist” style of Al Gore’s movie on global warming. I will avoid questions of style and stick to the science. Climate deniers try to confuse the issues, so I will focus on one point only.

He quotes Carleton University Professor Tim Patterson that 450 million years ago, the global climate was frigid in spite of carbon dioxide levels 10 times higher than present. This is a remarkably clever piece of writing, designed to sow confusion.

Stars like the Sun brighten as they age, and the Earth got about 5 percent less solar heat then. With an atmosphere like we have now, the Earth would have been a permanent iceball. There was a very long period of warm, balmy climate then for around 100 million years. In order to understand why the Earth was not permanently frozen, you have to include the greenhouse effect of all that carbon dioxide holding in the heat.

There was a short severe ice age in the middle of this warm period near the time he mentioned. So, the whole thing is definitely more complicated than he made it appear, and in fact you need to use the greenhouse effect to understand why the climate was warm most of the time.

We have a serious problem, related to the burning of coal, oil, and gas, and its effect on the whole planet. There are things we can do, but trying to mislead people about it is not one of the best choices.

Adrian Melott,

Lawrence