Kynes said:
Rath said:
Kynes said:
What people doesn't seem to consider is negative feedback. Higher sea temperatures increase the evaporation in the tropical areas, increasing the number of clouds and reducing the sun rays that reach the ground, cooling it. Higher levels of CO2 make forests and crop fields have higher yield, and this way the CO2 level reduces it's growth. We've had geologic eras with tens of times more CO2 in the atmosphere, with rain forests in the Sahara, with a much more green earth:
Is there a direct correlation of CO2 level and temperature? There doesn't seem to have a lineal correlation, at all. I think people are barking at the wrong tree, and lots of people believe we're much more important than we really are.
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Clearly five hundred million years ago the system was very different - there was more methane in the atmosphere, there was less in the way of carbon dioxide absorbing life, the sun was at a very different point in its life cycle etc. Carbon dioxide would still have had an important part in the climate but the level cannot be directly compared to current conditions. If you want a real comparison look at more recent data such as that from the Holocene period.
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Why we don't have this correlation today? In that graph we see differences of 20C related to differences of 100 ppm of CO2. If this were the truth, nowadays the Antarctica would be at -40C, as we have now ~400 ppm, and that's not what we see. May it be that the CO2 proportion in the atmosphere was related to the temperature, and not the temperature related to the CO2 proportion? There is a theory that implies that the oceans capture more or less CO2 in relation to the temperature, and it has approximately one thousand years of lag. If you take a look at the graph, it seems that the blue line follows the red line, and not the inverse.
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That is because historically CO2 does lag temperature. Historically the initial temperature rise (due to a natural orbital cycle) has caused a release of CO2 which has formed a greenhouse effect causing more warming, releasing more CO2 - it forms a self reinforcing cycle. Humans are the anamoly in that we're releasing large amounts of CO2 without a preceding temperature rise, we're basically kick starting warming.
