Int. J. Environ. Res. Public Health 2011, 8 1010 A good argument can be made that because the economic benefits of control should be discounted that the above fraction overstates the correction that needs to be made. Obviously a more refined estimate could be made taking into account the appropriate discounting of future reductions of economic benefits that would no longer occur, but it would be messy given the different discount rates that previous economic analysts have used, the sketchy basis for what the IPCC models and each previous economic analysis assumed in the regard, and the necessity to compute individual corrections for individual analyses. In the case of those economic analyses that have used near-zero discount rates, however, the discount rate adjustment would also be near zero. And these are probably the only analyses for which there is likely to be much question as to whether the remaining economic benefits after hypotheses 1 and 2 corrections have been made might still be significant. Also the overstatement of the residence time correction due to ignoring the discount rate correction may be counterbalanced by the assumption that the IPCC computer models used in earlier economic analyses effectively only assumed a 125 year residence time when in reality they may have assumed that it was over 1000 years. 2.6.2. Effect of Reduced CSF on the Economic Benefits of Emissions Control A lower CSF means a lower temperature increase, which also means lower economic benefits of control. Further research may show that the CSF is a little higher or a little lower, but it is clear that the UN IPCC CSF estimates are much too high based on the four real world tests summarized in Section 2.3. If valid physical science relationships were used in the case of hypothesis 2, the economic benefits would have been much less, probably less than one-fourth those used on the basis of the CSFs based on the 2007 IPCC best estimate. If the Lindzen/Choi [21,39] and Spencer/Braswell [41] CSF findings are correct, this means that benefit estimates that were based on the IPCC AR4 [5] best estimate of 3.0 °C need to be multiplied by a fraction no more than that determined by either the latest Lindzen [21,39] CSF estimate of 0.7 or the Spencer/Braswell [41] estimate of 0.6, each divided by 3. This yields a correction factor of between 0.20 and 0.23. For simplicity this article will assume this fraction to be less than one-quarter or 0.25. This assumes that the economic benefits can be scaled linearly with temperature. In reality, it appears likely that the benefits rise more rapidly with temperature, particularly at extremely high temperature changes, so one-quarter is an underestimation of the change in the actual revised benefits. One footnote is that a number of the economic benefit studies were done prior to the IPCC AR4, and the earlier IPCC reports used slightly different values for the best estimate for CSF, although the changes were small. Such reduced increases in global average temperatures do not appear to be large enough for there to be any significant risk of CAGW since even a doubling of CO2 levels would result in less than a 0.7 °C increase in global temperatures, which is well within temperature variations during the Holocene and during which no CAGW effects are known to have occurred. Hence by carefully examining the science, it is reasonable to conclude that CAGW effects are highly unlikely and probably impossible. That leaves the non-catastrophic economic benefits from avoiding relatively minor increases in global temperatures. Although extreme increases in global temperatures might have substantial adverse effects, it is not clear in the case of small increases suggested by CSFs of 0.6 to 0.7 °C whether increases of that magnitude would be beneficial rather than harmful. Tol [54] believes