How long does CO2 remain in the atmosphere
This question is importantbecause the IPCC and its supporters argue that human emissions of CO2 can remain in the atmosphere for hundreds, if not thousands, of years, and this persistence of human emissions in the atmosphere intensifies their contribution to global warming. The most authoritative estimates of the lifetime of CO2 in the atmosphere were stated in a number of recent papers by a Norwegian, Professor Tom Segalstad of the University of Oslo. (See especially Segelstad, T.V. (1996) “The distribution of CO2 between atmosphere, hydrosphere, and lithosphere; minimal influence from anthropogenic CO2 on the global ‘Greenhouse Effect’”. In Emsley, J.(Ed.),The Global Warming Debate. The Report of the European Science and Environment Forum. Bourne Press Ltd, Dorset ,U.K. Available at http://www.co2web.info/ESEFVO1.pdf ). He found that the measured lifetime, based on the studies of some 50 independent researchers, is at most about 5 years. The observed decrease in radioactive C14 after the cessation of atmospheric testing of nuclear weapons confirms that the half-life of CO2 in the atmosphere is less than 10 years. Segelstad concluded that even using the IPCC’s exaggerated estimate of the amount of CO2 emissions, human emissions would still only account for 0.45% (= 3.5 parts in 780) of the greenhouse warming in any particular year. This is equivalent to a rise of 0.1°C in the whole warming effect detected.