Clearing up CO2 confusion

In the Dec. 23 letter “Be skeptical of feds’ rapid action,” the writer argues that “carbon dioxide is not a pollutant. It is essential for all life on this planet.” He is confused by the term “pollutant.” Any excess can pollute. Here are some facts about climate change and CO2:

• Heat comes to the earth from the sun’s rays. The earth radiates its heat back in infrared rays. Some of those rays are contained in the atmosphere by water vapor, CO2 and other gases. That is good because we need a warm planet.

• There is about as much water vapor in the atmosphere now as there ever was, and it cycles from vapor to water in about one to three weeks. New CO2 in the atmosphere lasts for hundreds of years, and it accumulates. From the beginning of the industrial age, the atmosphere has gained 40 percent more CO2. The new carbon lacks Carbon 14, which takes millions of years to lose its radioactivity. So we know that the origin of new CO2 is fossil fuel burning. We also know there is a correlation between the CO2 and the global heat rise.

Carbon dioxide becomes a “pollutant” when it threatens future life as we know it.