But really, it's the good kind of "point of no return."

James Hansen, America's foremost climatologist:

Multiple lines of evidence indicate that the Earth's climate is nearing, but has not passed, a point of no return beyond which it will be impossible to avoid climate change with far ranging undesirable consequences.

The changes include not only loss of the Arctic as we know it, with all that implies for wildlife and indigenous peoples, but losses on a much vaster scale due to worldwide rising seas. Sea level will increase slowly at first, as losses at the fringes of Greenland and Antarctica due to accelerating ice streams are partly balanced by increased snowfall and ice sheet thickening in the ice sheet interiors. But as Greenland and West Antarctic ice is softened and lubricated by melt-water, and as buttressing ice shelves disappear due to a warming ocean, the balance will tip to rapid ice loss, bringing multiple positive feedbacks into play and causing cataclysmic ice sheet disintegration.

You know, I'm willing to bet that scientists don't use the word "cataclysmic" that often. When they do, we should probably listen. But this little nugget from Hansen's talk scares me. Really.

There has been publicity lately about restrictions on NASA communications with the media. NASA is working on that and I have high hopes that NASA will fix its problem and be a model for other agencies. We will see. But I am told by NOAA colleagues that their conditions are much worse than those in NASA. A NOAA scientist cannot speak with a reporter unless there is a listener on the line with him or her. It seems more like the old Soviet Union than the United States. The claim is that the listener is there to protect the NOAA scientist. If you buy that one, please see me at the break; there is a bridge down the street that I would like to sell to you.

You know, eventually we'll have to start referring to American media as "state-run", for accuracy's sake if nothing else.

You can read his full talk here, via Past Peak.