Well, I would have to go back and watch An Inconvienent Truth to see if he actually said that.
Al Gore, like most authors of papers suggesting AGW is a problem, often use a dozen or more Weasel Words per page in their papers. They choose words that are selectively interpreted by the bias of their readers that read the material.
As far as I know, he, or anyone else, never gave any time-frame as definitive.
But...
Weasel words. Probabilities on top of probabilities. If's on top of if on top of ifs.
They have nothing conclusive. If a "if" is worth 50%, then by the time you have three "ifs," the probability is only 12.5%. Yet they will tale multiple if's and claim 90 or 95% of a probability.
They rarely come out with any outright lie. They word things, and let the ignorant pundits do that for them.
Take the NASA consensus for example:
http://climate.nasa.gov/scientific-consensus/
Please note the paragraph that started with this:
Multiple studies published in peer-reviewed scientific journals (note 1) show that 97 percent or more of actively publishing climate scientists agree:
Now, I find it so ironic and pathetic at the same time that nobody given this information apparently has never read what those papers actually say. It leads me to believe that I might be the only one that ever actually read those studies referenced in note 1. No matter how many times I ask, nobody on the AGW scare side can point to anything in any of the referred studies that support the contention by the three listed at the bottom of the page.
Please note, none of them are climatologists!
Now I'm sorry for my long drawn out explanation here, and Vesper, I don't mean to undercut your point.
I'm just trying to help expose the big charlatan style sham, and how much this whole thing is far more political than factual.
There is no scientific evidence that what we do matters. It is all hyped and blown out of proportion. There is a natural component that might be most of any signal we see.
I'll say more later, but right now, I'm multitasking an at my limit of how many things I can do at once.