Int. J. Environ. Res. Public Health 2011, 8 996 Figure 1. Measured Mauna Loa CO2 measurements showing 50% error versus the cumulative expected CO2 level from burning fossil fuels. Source: [8], Slide 14. Figure 2. Effective lifetime for CO2 in the atmosphere based on a variety of methods. Source: Sundquist [18] and Segalstad [10], as presented in [8], Slide 23. Effective atmospheric CO2 lifetime The effective lifetime for CO2 in the atmosphere, can be determined by the help of radioactive, radiogenic, and stable isotopes. All measurements with different methods show short effective lifetimes for atmospheric CO2, only ca. 5 - 6 years. Sundquist (1985); Segalstad (1998) The significance of Segalstad‘s findings cannot be overestimated assuming his data and analysis are correct. Four percent of atmospheric CO2 is in the noise level and contrasts sharply with the IPCC‘s 21 percent estimate. The 5+ years RT explains why four percent is reasonable and also contrasts greatly with the IPCC‘s apparent assumptions. Segalstad‘s findings cast great doubt on some of the most important IPCC assumptions concerning CO2 (as noted by Segalstad [8]) as well as on the indirect assumptions made by most if not all economists who have attempted to value the economic benefits of CO2 emissions control. Among many other observations, Segalstad points out that a RT of 5 years implies that about 135 GT C is exchanged out of the atmosphere each year. ―This is far more