I've learned by now to be cautious about the larger policy implications of any single peer-reviewed paper in the scientific literature. There are too many ways for us non-scientists to trip over our relative ignorance of statistical methodology and data processing.
Still, sometimes I can't help myself. The journal Science recently published a review article analyzing the existing body of literature on paleoclimate -- i.e., data about how the Earth's climate behaved in the past. So in this case, I'm not really reacting to just one paper, but rather to a summary of many others. And some rather hideous findings. You can read a summary for policy wonks here. On our current course, the literature suggests, greenhouse gas concentrations one hundred years from now will rival the highest levels ever seen in the history of this planet. At those levels, the Earth's mean annual surface temperature in the past reached about 87 degrees Fahrenheit. That's up from 59 degrees Fahrenheit today.
As often as I read this kind of stuff, I still can't get over how incomprehensibly awful it is. Or how little clue the policy wonk community has about what's really happening. An 87 degree global mean surface temperature will burn human civilization to ashes. It will, according to the article referenced above, make the middle latitudes of the planet literally uninhabitable -- the combination of heat and humidity will cause respiration in the human body to cease. Whatever is left of humanity will be forced to tiny enclaves in Siberia, northern Canada, and Antarctica. With a vast zone of death separating them for thousands of years, until the temperature someday subsides.
But tonight's State of the Union address will talk about taxes, entitlements, and Afghanistan.