The DOE Report on Plant Life During Low CO2
One of the frequently repeated tropes in climate contrarian circles is the supposed " line of death " at 150 ppm below which, we're told, all photosynthesis stops, so all plant life dies and there's a mass extinction of life on Earth. CO2 Coalition loves to trot out this trope to claim that, since CO2 became as low as 170 ppm during the glacial cycles of the Quaternary, we were dangerously close to a mass extinction. They claim we're still "CO2 starved." They also tell us that Berner's 2001 CO2 models shows "an alarming downward trend toward CO2 starvation." We're then apparently supposed to be thankful for fossil fuel emissions that have saved us from perhaps the extinction of all life on earth. The DOE report, authored by the "climate working group" (CWG), tones down this rhetoric a bit, but it's essentially the same claim with slightly different numbers: "At the end of the last glaciation CO2 levels had fallen to...