Int. J. Environ. Res. Public Health 2011, 8 1018 extremely rapidly with adequate preparations, unlike (probably futile) attempts to reduce atmospheric CO2 levels decades in advance, as currently proposed by the UN and some Western governments. On the other hand, the risk of CAGW appears to be so low (given the low CSF and the short residence time of the fossil fuel contribution to increasing the level of Earth‘s atmospheric CO2) that it does not appear to be worth even trying to do anything to mitigate it currently, particularly since the world has any number of other problems that appear to be more urgent. But if an economically efficient control effort should ever be needed, which eventually it probably will as we approach the end of the Holocene with a high likelihood of a new ice age, the most economically efficient approach appears to be by using geoengineering such as SRM assuming adequate research and validation has been undertaken beforehand and reasonable implementation approaches are devised. So it would appear worthwhile to undertake these comparatively inexpensive preparatory efforts anyway. 5. Some Comparisons with Other Economic Analyses of Climate Change Control There have been at least 16 economic analyses of climate change control in the literature broadly construed. Table 3 summarizes the economic effects of the increases in global temperatures shown in most of these analyses, based primarily on Tol [54]. In addition, there have been two major government reports: one in Great Britain, Stern [63], and one in Australia, Garnaut [64]. Finally there is a more popular article by Krugman (2010) [65]. Tol [54] summarizes the findings of most of the academic articles/books with estimates of the uncertainty given in brackets, either as standard deviations or as 95% confidence intervals where available. Fragmentary data from the other three studies above are listed at the bottom of Table 3. Most of the first 13 studies listed in the table find that temperature increases of 1 to 3 °C will result in decreases in GDP (or more accurately GWP) of a few percent. The principal outliers would appear to be those by Tol [54,74], Stern [63], Garnaut [64], and Krugman [65]. Tol [54] believes that minor warming would result in higher growth and is thus one of the principal outliers on the optimistic side. The last three, on the other hand, appear to be outliers on the pessimistic side. Stern has been criticized by Nordhaus [79] for using unreasonably low interest rates to justify what Krugman [65] calls the ―big bang‖ approach, which also applies to the other major government report by Garnaut [64], which uses an even lower rate. I can only agree. The exact effect of the reduction in the value of the CSF on the outcome of each analysis would require detailed reanalysis in each case, but except for Krugman and the two government reports it seems likely that it would make the difference between positive and negative net benefits in most cases. This is the case for the one positive scenario reported by Tol [54]. The next two subsections will summarize two of the most recent analyses by Krugman [65] and Lomborg [58], both of which have unusual and significant features with regard to this analysis and illustrate the profound effect of the basic assumptions by each analyst on their recommendations.