It will be funny in a few years
I am sure that in a few years we'll all look back on this "humans changed the climate" fallacy in the same way we do about the Earth being flat, Moon made from cheese, and super-natural creator of Heavens and Earth. DOH, we still have some way to go to overcome that one too!!!
Predicting climate changes based on very short historical evidence is naive at best and dangerous at worst. A recent Ice Core sample from Greenland showed that there was insects and vegetation in that region between 150,000 and 400,000 years ago. This is a region now covered by over 1 Km of ice. I am sure that the last few millions of years have seen the planet warm and cool for all sorts of reasons, and the Eco-nutters who are more worried about scare-mongering and fund raising than scientific evidence should put their 20 years of research into a planet life-cycle context.
Al Gore.... = Al Bore