Dec 062012
A temperature increase of 4 degrees C is now thought likely to cause the disintegration of an organized global community. A four degree world will likely be so altered that human society cannot adapt to it…Worse, there is a scientific consensus today that holding warming to 2 degrees C is no longer possible given the emissions to date and the failure to cut back. Hence, avoiding dangerous human-caused interference with the climate system is no longer possible.
via Avoiding the Nightmarish “Four Degree World” of 2060: We must Act Now | Informed Comment.