Enough Evidence Yet ???

"What we're seeing is a process in which we start to lose ice cover during the summer, ... so areas which formerly had ice are now open water, which is dark.

"These dark areas absorb a lot of the Sun's energy, much more than the ice; and what happens then is that the oceans start to warm up, and it becomes very difficult for ice to form during the following autumn and winter.

"It looks like this is exactly what we're seeing — a positive feedback effect, a 'tipping-point'."

Found at Kevin Drum's The Washington Monthly blog.