The Lingering Effect of Anthropogenic CO₂. (May 11, 2009)

The April 30, 2009 issue of the journal Nature features three articles under the joint heading "The Climate Crunch".

The first "A burden beyond bearing" by Richard Monastersky focuses on the retention of carbon dioxide in earth's atmosphere once produced; Nicola Jones looks into the feasibility of overall scrubbing of the atmosphere of CO₂ and sequestering it, and Oliver Morton discusses suggestions featuring geoengineering.

Below we reproduce two charts that make a point that has gained scant attention in the popular media -- the addition of anthropogenic CO₂ once introduced into the atmosphere is very slow to be removed and its predicted effect on global warming will be even slower to be reversed.

For example, if by 2050 CO₂ levels reached 550 parts per million the predicted temperature rise above pre-industrial levels will be 2^oC. Over the next hundred years, if then the anthropogenic CO₂ contribution immediately drops to zero,  the CO₂ level would drop to near 500 ppm, but the temperature increase is predicted to remain at 2^oC.

The graphs depict the case for cessation of all anthropogenic CO₂ production at 400 ppm, 550 ppm and 1000 ppm.