New UN Report Calls Global Warming Unstoppable

The UN's Intergovernmental Panel on Climate Change reviews the most recent studies of retreating ice, rising seas and warming temperatures, and reports on supercomputer simulations of what might happen next. Three days of wrangling by teams from more than 100 countries has produce a 20-page summary and the most urgent warning ever. It says that the alternative to action is worldwide calamity. The American Enterprise Institute, funded by ExxonMobil, has offered $10,000 apiece to skeptic scientists or economists who can find flaws in the report. Andrew Revkin covers the environment for the New York Times.