Thank you for running the column by William Gross (“Maine Voices: EPA distorts basic science by calling CO2 ‘pollution,’ “ Aug. 13).

While the Press Herald often runs editorials, letters and columns on so-called carbon pollution, this is the first time an engineer has been allowed to lay out the truth about CO2.

Anyone who can remember eighth-grade science knows about the carbon cycle so necessary to life on Earth. We exhale CO2, and plants inhale it.

Mr. Gross made the point with his citing of greenhouses using increased CO2 to enhance plant growth. He could have gone further by citing U.S. Department of Agriculture studies that show increases in CO2 result in corresponding increases in crop yields.

More evidence that CO2 is not a pollutant can be found in the submarines of our Navy. When the vessels are submerged, the air inside contains as much as 5,000 parts per million of CO2. If our crews can function normally without side effects at those levels, 400 ppm is certainly not a threat to our health.

That leaves the so-called “global warming,” and it has just about come to a halt over the past 18 years.

Thank you, Mr. Gross.

Dave Irons