David and I are clashing over "falsifiability" in our current views regarding federal efforts to mitigate climate change. I have challenged him to specify if there is any possible unfolding of events in which he would admit, "Whoa, that guy Murphy was right about this!"
Now David understandably misunderstood me (I think). It seems he is interpreting my claim as something like, "Suppose we are overestimating climate sensitivity. Then we'll be mad that we produced too few SUVs when temperatures only rise 0.8C by 2050!"
Although I am indeed concerned about the weight that many economists are placing in the IPCC best-guess, that's not directly relevant to my challenge. I have more in mind things like: the US goes on cap and trade, and the corruption is so rampant that US emissions targets keep getting pushed back, more permits are sold during the next recession, etc. etc., such that CO2 emissions don't diverge much at all from projected "business as usual" levels.
For my part, I admitted that if there were an additional warming of 1C by 2020, then my quibbles about the climate models would be totally wrong, and I (in 2020) will be embarrassed at my Nordhaus paper. For another possibility, if US goes on cap & trade next year, and then adheres to the targets established in that original timeline, then I will also admit (when it happens) that I am being way too cynical in 2008.
But so far David has not even listed a possible universe in which he will regret his current position. That should concern him, in my opinion. Is he really as confident in AGW--and the need for the federal government to do something about it, along the lines of carbon tax or cap & trade--as he is in, say, the Pythagorean theorem?
(BTW in everyday conversation I would not be so narcissistic as to bring up every other conversation I have had during the week. But presumably some people come and check this blog because they're bored out of their minds and so I want to make it one-stop shopping for all of my online banter.)