Common sense tells me that the fact that we exist and are the result of life having evolved over billions of years indicates that the climate is quite stable as far as life forms are concerned. This is especially true given that "[f]ive hundred million years ago carbon dioxide was 20 times more prevalent than today" and that the climate has been adequately stable to support evolution and ecosystem diversity through catastrophic disasters such as meteor strikes and massive volcanic eruptions.
It is true that common sense isn't always correct. However, when a proposition defies common sense, I require an especially rigorous burden of proof on those making the proposition. That burden of proof is nowhere close to being met.
Global temperatures are affected by the concentration of CO2 in the atmosphere. All else being equal, a doubling of the concentration of CO2 will increase the average global temperature by 1.2 degrees Celsius. An increase of 1.2 degrees Celsius is very unlikely to be catastrophic.
The scientific case for catastrophic man-made global warming rests on a set of computer models called General Circulation Models (GCMs). These models incorporate positive feedbacks that amplify the warming due to CO2. In other words, a little bit of warming due to CO2 becomes much more warming because of hypothesized effects such as increased water vapor (water vapor also traps heat). Instead of 1.2 degrees Celsius for a doubling of CO2, the GCMs, with the positive feedbacks predict much larger warming, in the range of 1.5 to 4.5 degrees Celsius per CO2 doubling.
These feedbacks, while plausible, are not proven. Indeed, some of the effects expected by the GCMs from such feedbacks have not been observed in the real world. For example, while the models predict the warming of the tropical troposphere to be 2 to 3 times larger than the warming of the surface, this relationship has not been observed. In fact, recent research based on measured Sea Surface Temperatures and measured outgoing radiation indicate an overall negative feedback which means that there could be substantially less than 1 degree increase in temperature resulting from a double of CO2. Also, using finer cloud simulations within the existing GCMs seems to reduce the predicted temperature increases. The above are just a sampling of numerous articles that cast doubt on the more extreme global warming predictions.
There are other plausible explanations for whatever warming occurred last century. For example, changes in solar activity may have significant impact on cloud formation in addition to its small, direct effect on temperature. To date, relatively little effort has been expended on researching these alternate explanations, but they are, in my opinion, plausible, and not disproved.
In summary, the science of Catastrophic Global Warming defies common sense, has not been proven, and alternate explanations have been neither adequately researched nor disproved.
Any significant climate change (in either direction) will produce winners and losers, both in terms of life forms in general and human life in particular. However, given the observation that the density of both life and humanity are much higher in very warm climates than very cold climates coupled with the fact that the GCMs predict that most of the warming will occur in colder climates leads me to doubt predictions of severely adverse economic impacts from global warming.
One of the most dire and well known economic analyses of climate change is The Stern Review. It concludes that we should immediately begin investing at least 1% of global GDP in order to reduce CO2 emissions and that an investment of this magnitude (over $400 billion per year) will produce positive future returns by reducing the impact of climate change.
However, in my opinion, the Stern Review and other economic analyses with similar findings are seriously flawed. First, the Review "depends decisively on the assumption of a near-zero time discount rate combined with a specific utility function. The Review’s unambiguous conclusions about the need for extreme immediate action will not survive the substitution of assumptions that are consistent with today’s marketplace real interest rates and savings rates.". In other words, the Review assumes far, far lower interest rates than can be found in the real world. Spending large sums of money on preventing CO2 emissions will adversely affect billions of people now, miring substantial numbers of those in prolonged poverty. Note that this spending, to be effective, also assumes some level of efficiency. Unfortunately, governments are not particularly good at efficiency.A second problem is that the Review seriously underestimates future innovations which will mitigate the impact of climate change. If one considers the technological progress that has been made in the last century and projects it forward to the next hundred years, it seems nearly certain that humanity will be ever more connected, mobile, and able to cope with the environment. It's also far from clear that CO2 emissions will continue to increase as predicted. Other technologies such as solar, geothermal, nuclear fission and fusion, etc., will continue to become more cost effective and may displace fossil fuels as energy sources anyway.
In addition, there are likely to be some benefits to warming and these benefits are downplayed in the Stern Review. For example, other economic studies conclude "that moderate warming is an overall benefit to mankind because of higher agricultural yields and many other reasons." This fits with the observation that mankind does better where it's very warm rather than where it's very cold.
Even if the upper end of the predicted warming occurs and even if the economic analyses like the Stern Review are accurate, it's far less clear that it's useful to take action if only a few rich countries are willing to do anything about.
India and China have flat out refused to reduce future emissions with India even questioning the science of global warming. As these countries represent nearly ½ the global population, it make little sense for much smaller countries such as the United States to live substantially less well in order to slightly slow the rate of increase of CO2, especially given that the per capita increase in CO2 emissions in the United States is slowing anyway.
There is no reason to get governments involved. If taking action is such a good idea, people can act individually and in non-government groups in order to reduce their carbon footprints. If there are only a few skeptics who don't follow, those few skeptics will have limited impact. In other words, if you think reducing carbon footprints is a good idea, by all means, reduce yours.
There's very little evidence that the world will be able to take significant concerted action anyway. For example, Lomborg shows that the Kyoto Treaty (if the signatories had actually lived up to there promises) would have only delayed the climate change due to CO2 emissions by six years out of 100.
Catastrophic Global Warming has all the trappings of a religion. The god is “Gaia”, the pope is Al Gore, the priests are (most) climate scientists, they know the Truth (with a capital “T”) with certainty, the message is essentially “Repent or the end is nigh!”, Creationism is alive and well since “Gaia” is apparently supposed to have a specific CO2 level and associated climate, and heretics are dealt with nastily.
As such, Catastrophic Global Warming should be subject to the same Separation of Church and State doctrine as other religions. The believers should, of course, be free to proselytize and live their own lives according to their beliefs, but should not be allowed to impose their beliefs on the rest of us via government taxes and regulation, and should not be free to proselytize in our children's schools.
The concept that if we don't take action against CO2 emissions then we're immoral is not fundamentally different than any other religion that claims that you're immoral if you don't believe in God and live your life according to the Dogma of that religion. There is no objective morality here, Carbon Dioxide has no morally correct level, and there is no morally correct global temperature or climate.
Furthermore, when subjective opinions are stated as objective fact with the goal to control the behavior of others, that is a significant evil. When the majority or even a vocal minority imposes its subjective beliefs on others, that is tyranny and is a major evil.
Taking action to reduce CO2 emissions in the United States in order to prevent the possibility of Catastrophic Anthropogenic Global Warming makes little sense from any rational perspective. The science is not adequately well understood, economically it makes little sense, and it's not politically possible on a global scale. If people wish to choose that as a religion, that's fine, as long as their beliefs aren't imposed on the rest of us.
 Committee on the Science of Climate Change, National Research Council. Climate Change Science: An Analysis of Some Key Questions, pp 6-7.
 Intergovernmental Panel on Climate Change (IPCC). Climate Change 2007: Synthesis Report, p 38.
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 Lindzen, R.S., Choi, Y.S. (2009) On the Determination of Climate Feedbacks from ERBE Data, Geophysical Research Letters, Vol. 36, No. 16. (26 August 2009), L16705.
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Happer, W. (2009): William Happer Testimony to Senate Energy Committee, February 25, 2009
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Los Angeles Examiner
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