[O]ne would need to prove the following 6 points before one could make a scientific case that we should implement major changes in our laws with respect to CO2 emissions:I think the most interesting new point in this post, one I wasn't aware of, is this article in the Telegraph: "There IS a problem with global warming... it stopped in 1998." For several years now, the globe has stubbornly resisted the global warming models, and not exhibited any warming.
1) That global warming was actually happening.
2) That it was the result of human activity (not just normal cyclical natural variations).
3) That the degree of human-caused global warming would cause significant harmful consequences.
4) That these consequences could be reversed by taking certain actions.
5) That any such proposed action (such as the Kyoto treaty) would actually be effective in preventing/reversing the harm.
6) That any such proposed action wouldn't cause worse harm than it prevented (i.e., that the "cure" wouldn't be worse than the "disease").
Note that all 6 elements would have to be proven true before it would be appropriate to adopt a major international treaty like Kyoto.
Numerous news articles have shown serious problems with points (5) and (6). Based on my reading, I believe there's also significant legitimate scientific uncertainty about (1) through (4) as well.
Further, Roger Pielke's blog Climate Science has the following:
Update April 4 2006
The Climate Science Weblog has clearly documented the following conclusions since July 2005:
1. The needed focus for the study of climate change and variability is on the regional and local scales. Global and zonally-averaged climate metrics would only be important to the extent that they provide useful information on these space scales.
2. Global and zonally-averaged surface temperature trend assessments, besides having major difficulties in terms of how this metric is diagnosed and analyzed, do not provide significant information on climate change and variability on the regional and local scales.
3. Global warming is not equivalent to climate change. Significant, societally important climate change, due to both natural- and human- climate forcings, can occur without any global warming or cooling.
4. The spatial pattern of ocean heat content change is the appropriate metric to assess climate system heat changes including global warming.
5. In terms of climate change and variability on the regional and local scale, the IPCC Reports, the CCSP Report on surface and tropospheric temperature trends, and the U.S. National Assessment have overstated the role of the radiative effect of the anthropogenic increase of CO2 relative to the role of the diversity of other human climate climate forcing on global warming, and more generally, on climate variability and change.
6. Global and regional climate models have not demonstrated skill at predicting climate change and variability on multi-decadal time scales.
7. Attempts to significantly influence regional and local-scale climate based on controlling CO2 emissions alone is an inadequate policy for this purpose.
8. A vulnerability paradigm, focused on regional and local societal and environmental resources of importance, is a more inclusive, useful, and scientifically robust framework to interact with policymakers, than is the focus on global multi-decadal climate predictions which are downscaled to the regional and local scales. The vulnerability paradigm permits the evaluation of the entire spectrum of risks associated with different social and environmental threats, including climate variability and change.
Emphasis mine. Roger Pielke is a very reputable climate scientist at Colorado State, and doesn't have a stake in the MBH vs MM controversy on which we've reported in the past.