Says who? Just Richard S. Lindzen, Alfred P. Sloan Professor of Atmospheric Science at MIT:
“…their research is forced, whether the evidence supports it or not, into Mr. Gore’s preferred global-warming template–namely, shrill alarmism. To believe it requires that one ignore the truly inconvenient facts. To take the issue of rising sea levels, these include: that the Arctic was as warm or warmer in 1940; that icebergs have been known since time immemorial; that the evidence so far suggests that the Greenland ice sheet is actually growing on average. A likely result of all this is increased pressure pushing ice off the coastal perimeter of that country, which is depicted so ominously in Mr. Gore’s movie. In the absence of factual context, these images are perhaps dire or alarming.
They are less so otherwise. Alpine glaciers have been retreating since the early 19th century, and were advancing for several centuries before that. Since about 1970, many of the glaciers have stopped retreating and some are now advancing again. And, frankly, we don’t know why.”