People often ask me, "The Green Miles (no, people don't actually call me that, but it's my blog so just go with it), when did global warming go from being a matter of debate to accepted reality? What was the tipping point?"
My answer is that there were two distinct tipping points. The first came on May 24, 2006 when Al Gore's documentary, An Inconvenient Truth, was released in theaters. After that, people stopped debating whether global warming is happening. The debate shifted to why global warming is happening.
The second tipping point came on February 2, 2007, when the U.N.'s Intergovernmental Panel on Climate Change released a report declaring that "with near certainty — more than 90 percent confidence — that carbon dioxide and other greenhouse gases from human activities have been the main causes of warming in the past half century." That shifted the debate from why global warming is happening to what we can do to avoid its worst effects.
Now today, we have the possibility of the third tipping point. Al Gore and the IPCC have been recognized for their work with the Nobel Peace Prize. Will the debate shift now from what we can do to international agreement on strong action to limit greenhouse gas emissions?
For the environmental movement, the Prize is a watershed event. But for Al Gore, after getting screwed by the political media in 2000, it must be especially satisfying. I'd think he's walking around like this today: