Sometimes silence can reveal more than words. And the complete silence of both candidates during last night's (and

previous nights') presidential debate on climate change speaks volumes about just how dead the issue now is. Indeed, this is the first time in 24 years that neither candidate thought it fit to mention what Al Gore has billed the biggest threat ever to "human civilization as we know it." That Obama didn't feel the need to devote even a lame half-a-sentence to it in the 270 minutes of free airtime he has gotten shows what a remarkable fall this defining challenge of our generation has enjoyed. Laments Evan Lehman of Environment & Energy:

This is the first time since 1988 that climate hasn't been mentioned in the presidential debate cycle, Johnson of Climate Silence said in a post that provides partial transcripts to the contests. Back then, Republican vice presidential candidate Dan Quayle said, "the greenhouse effect is an important environmental issue."

In 2008, Obama and Sen. John McCain (R-Ariz.) discussed efforts to reduce emissions in three debates, including in one presided over by last night's moderator, Bob Schieffer. Their running mates also talked about it, with Sarah Palin (R-Alaska) touching on the dangers faced by her home state. This year's omissions make the prospects cloudy for climate action in the next four years, whether the nation is led by Obama or Romney.

Indeed. Which proves one thing: Just what a waste Al Gore's life has been. His career is dead. His marriage to Tipper is dead. His cause du juor is dead. The only thing he can hang on to….hmmm….can anyone think of anything?