@Olivier5,
youre right an the deniers have totally ignored the complex uptake of all"greenhouse" gases and atmospheric stable isotopes in the Greenland Ice cores. First came a host of greenhouse gases and then came the warmup nd interstadial periods.
Its food for deniers to try to pick at tiny isolated "factoids", but even the oil companies are coming around to the entire story.
Actually, since the Paleozoic, CO2, based upon the lessening occurrences of hematite, limestone and aragonite deposits, is DECLINING. The full mix o all sorts of greenhouse gases an vapors have taken up the bulk o responsibilities for GW. (most of which have only begun appearing since the post industrial age, what Ive called the CHEMOCENE in classes).
PLANT EVOLUTION is going to have to speed up and the ratios of C3 v C4 plant life will have to change, or we will be in a big bag of hurt.