During the peak of the Pliocene era 4 million years ago, CO2 was 415 ppm, temperature was 4 C higher than now,?
Answers
Answer #1 | 23/12 2013 17:37
Who knows? Give Me $39 Billion and I will build a time Machine .
Ice Cores don't last 4 million years .
Positive: 50 %
Answer #2 | 24/12 2013 08:46
if the question is is 415PPM an upper limit for CO2, the answer is no. There have been concentrations well above that hundreds of millions of years ago. It's entirely possible that humans may push it to 500PPM if we keep burning fossil fuels.