http://www.geolsoc.org.uk/gsl/views/policy_statements/page7426.html
How did levels of CO2 in the atmosphere change during the ice age?
The atmosphere of the past 800,000 years can be sampled from air bubbles trapped in Antarctic ice cores. The concentrations of CO2 and other gases in these bubbles follow closely the pattern of rising and falling temperature between glacial and interglacial periods. For example CO2 levels varied from an average of 180 ppm (parts per million) in glacial maxima to around 280 ppm during interglacials. During warmings from glacial to interglacial, temperature and CO2 rose together for several thousand years, although the best estimate from the end of the last glacial is that the temperature probably started to rise a few centuries before the CO2 showed any reaction. Palaeoclimatologists think that initial warming driven by changes in the Earth’s orbit and axial tilt eventually caused CO2 to be released from the warming ocean and thus, via positive feedback, to reinforce the temperature rise already in train28. Additional positive feedback reinforcing the temperature rise would have come from increased water vapour evaporated from the warmer ocean, water being another greenhouse gas, along with a decrease in sea ice, and eventually in the size of the northern hemisphere ice sheets, resulting in less reflection of solar energy back into space.
I'm in good company with my beliefs that CO2 concentration is not a climate driver. It's an effect of warming oceans.
How did levels of CO2 in the atmosphere change during the ice age?
The atmosphere of the past 800,000 years can be sampled from air bubbles trapped in Antarctic ice cores. The concentrations of CO2 and other gases in these bubbles follow closely the pattern of rising and falling temperature between glacial and interglacial periods. For example CO2 levels varied from an average of 180 ppm (parts per million) in glacial maxima to around 280 ppm during interglacials. During warmings from glacial to interglacial, temperature and CO2 rose together for several thousand years, although the best estimate from the end of the last glacial is that the temperature probably started to rise a few centuries before the CO2 showed any reaction. Palaeoclimatologists think that initial warming driven by changes in the Earth’s orbit and axial tilt eventually caused CO2 to be released from the warming ocean and thus, via positive feedback, to reinforce the temperature rise already in train28. Additional positive feedback reinforcing the temperature rise would have come from increased water vapour evaporated from the warmer ocean, water being another greenhouse gas, along with a decrease in sea ice, and eventually in the size of the northern hemisphere ice sheets, resulting in less reflection of solar energy back into space.
I'm in good company with my beliefs that CO2 concentration is not a climate driver. It's an effect of warming oceans.