To be fair, he had no proof that global warming is caused by humans. Global warming (and global cooling) has existed for thousands of years before mankind, and will continue to exist for thousands of years after we're gone.<quoted text>
Thank you for your "Mysterian" contribution. You have no proof that Global Warming exists other than AL Gore says it is. Liberalism is a mental d.i.s.o.r.d.e.r.
The sticking point is whether we're causing it. And the answer to rational reality-based people is "there is no significant evidence for it so far".