Jerry, with respect, the Cato letter seems to be to be neither very relevant nor helpful. Here it is, in full:
“Few challenges facing America and the world are more urgent than combating climate change. The science is beyond dispute and the facts are clear.”
PRESIDENT-ELECT BARACK OBAMA, NOVEMBER 19, 2008
We, the undersigned scientists, maintain that the case for alarm regarding climate change is grossly overstated. Surface temperature changes over the past century have been episodic and modest and there has been no net global warming for over a decade now. After controlling for population growth and property values, there has been no increase in damages from severe weather-related events. The computer models forecasting rapid temperature change abjectly fail to explain recent climate behavior. Mr. President, your characterization of the scientific facts regarding climate change and the degree of certainty informing the scientific debate is simply incorrect.
Under what I consider to be the most natural reading of the words in these brief passages, I disagree with both of President Obama’s sentences, and agree with each sentence signed onto by the scientists. But, both seem to me to be examples of what you call “shouting loudly.”
Yes, the case for alarm usually is overstated by advocates (and assuming that the first sentence of the open letter refers specifically to the quote from President Obama, it certainly is overstated in this case, in my view). That doesn’t mean, however, that there is no cause for alarm.
Yes, it’s true that it is very difficult to assign material historical damages to AGW, and global temperatures have been pretty much flat for a decade, and global climate models have not demonstrated that they can pass falsification trials for prediction of temperature change on a decadal scale. But on the other hand, no respectable scientist disputes that CO2 redirects long-wave radiation but not short-wave radiation. At some point, with high enough concentration in the atmosphere, it will create severe problems. There are trade-offs involved around how much wealth we sacrifice today in order to reduce by some hard-to-quantify amount the chance of large losses in the future.
President Obama ignored the trade-offs and uncertainties, and instead chose to make the simpler, but false, argument that (to paraphrase) “science says do what I tell you or we’ll all going to die.” Of course, he’s a politician. It would have been nice to see scientists acting like scientists, and explaining both sides of the issue in terms of the deep uncertainties that surround it.