To the editor:

Arly Allen’s Aug. 31 “Take A Stand” debunking human carbon dioxide emissions as a danger for global warming contains some true statements, but very misleading ones. He reminds us that the sun provides heat for the earth. This is true, but it is well-known to science that CO2 acts just like auto window glass, trapping the heat.

He mentions warm and cool periods known over the last few millennia, each several hundred years long, and notes that the “present period” (length unspecified) isn’t as warm as some. Misleading again. You need to look at levels since 1800, when coal burning escalated. In fact, much of the CO2 increase came only since World War II. The ’90s was the warmest decade worldwide in the last thousand years.

Ice cores show that, earlier, the highest CO2 levels in the last 420,000 years were 300 parts per million volume. We passed that around 1920 and are now at about 360. He notes that at some point in the past the earth was warmer, CO2 was much higher, and life did fine. Yes. It was really good for dinosaurs.

Mr. Allen would do well to get his information from scientific consensus sources, such as the American Geophysical Union, whose 41,000 members include more than 10,000 experts on climate change and atmosphere. Exact changes cannot be predicted, but are likely to be dangerous.

We cannot instantly replace fossil fuels, but conservation will help while we research alternatives.

Adrian Melott,

Lawrence