I caught the second half of ABC's major production on a dismal projected future for the United States due to global warming, and was very impressed to see a network put forward one expert after another with pessimistic scenarios. How refreshing to see that the real debate is more about how bad/how soon than about whether.

Excerpts from ABC's description of the special:

It seems outlandish, extreme -- even impossible. But according to cutting edge scientific research, it is a very real possibility. And unless we make drastic changes now, it could very well happen.

Experts have a stark warning: that unless we change course, the "perfect storm" of population growth, dwindling resources and climate change has the potential to converge in the next century with catastrophic results.

You can watch the entire production online at
http://abcnews.go.com/Technology/Earth2100