Ppm Quotes
- About fifty million years ago...geological evidence indicates CO2 levels were several thousand ppm, much higher than now. And life flourished abundantly. — William Happer
- If humanity wishes to preserve a planet similar to that on which civilisation developed and to which life on Earth is adapted, paleoclimate evidence and… — James Hansen
- We run enormous risks and we know what kind of reductions of greenhouse gases are necessary to drastically reduce risks. Reducing emissions by half by… — Nicholas Stern