A May 11 letter to the editor by Terry Hansen said this: “... the highest ever greenhouse gas concentration in history was observed at Mauna Loa Observatory: 418.12 parts per million (ppm) CO2 (carbon dioxide) in the atmosphere” (“Letter: It’s time to heed warnings on climate change”). The author used this quote to argue in favor of taxing CO2 in order to reduce greenhouse gas emissions.
That is both wrong and misleading because at 418 ppm, CO2 is very near its lowest level since the creation of the Earth 4.6 billion years ago (my definition of “ever”).
Here are the facts. Geological evidence shows that CO2 was as high as 7,500 ppm 350-450 million years ago. Today, NASA satellite images show the Earth has been greening over the last 20 years, mostly due to increasing CO2. Additionally, taxing CO2 will not decrease pollution because it is neither a pollutant, nor does it contribute to the formation of pollutants. We need more of it, not less. CO2 increases crop yields that support our rapidly growing population. Finally, CO2 and H2O are greenhouse gases that prevent our Earth from freezing.
CO2 is a colorless, odorless, nontoxic gas of all life on Earth.