The peer-reviewed literature is unanimous in finding that the residence-time of CO2 in the atmosphere is about 7 years. The UN’s climate panel, however, chooses a complex and unsatisfactory definition of residence-time that allows it to pretend that the residence time is in fact 100 years. This is one of many respects in which the climate panel, while claiming to represent the “consensus” of scientific opinion, is in fact entirely at odds with the peer-reviewed literature.
Crakar is confusing the residence time of an individual CO2 molecule with the residence time of an increased CO2 level. CO2 cycles in and out of the atmosphere constantly and in quantities much larger than we emit (a fact continually misrepresented by the denialist echo chamber) so an individual molecule will on average stay in the air a small number of years. I am writing this quickly and offline so am not verifying the quoted figure crakar offers, but the flaw in his understanding is clear regardless of the real value.
The critical property humanity must be concerned with is not how long or how many CO2 molecules actually made from fossil fuel combustion are in the air, but how long will levels driven higher by us stay higher. This figure is actually on the order of centuries.
I gratefully accept proper figures/calculations/citations in the comments.
An honest skeptic faced with this simple and clear distinction will acknowledge that this “science says 7, IPCC says 100″ canard is false. What will crakar and snowman do? And I wonder how they reconcile a 7 year residence time with the quantity of extra CO2 now in the air, it is much more than 7 year’s worth.
Can you say “cognitive dissonance”?