EPA's CO2 Endangerment Finding is Endangered

"In a narrow 5-4 decision in 2007, the U.S. Supreme Court authorized the EPA to consider the greenhouse gas CO2 as a “pollutant” under the terms of the Clean Air Act—provided EPA could demonstrate that CO2 posed a threat to human health and welfare. (CO2 is a colorless gas, non-toxic and non-irritating, and a natural constituent of the atmosphere. In the geological past, CO2 levels have undergone wide variations—from as low as one half up to twenty times the present level.)"