[ConstantineX]

It's a pretty good global warming video, but he's wrong. His argument is basically an existential risk (really MAJOR risk) argument. He sets up a grid with the actions on one axis, and the possible probable outcomes on the other. He makes the point that we can't determine the probabilities that well, but we can control our present actions. He proceeds to sum the "utility" (that's what his grid is measuring) across rows of actions, attempting to logically choose the better one. Because "no action" on global warming will lead to economic, political, social and environmental failure, he claims that more than compensates for the economic cost of being wrong about global warming and spending the money anyway. He concludes that even with knowing the relative weights (probabilities) of the possible outcomes, it makes sense to take action on global warming.

But he's wrong. The weights DO matter, a great deal. He's mainly wrong on the "no action", "yes on global warming" square. He overstates the costs of non-action, because EVEN IF global warming is true, because he ignores economic growth and its possibility of immediately solving those crises. Ignoring economic growth makes the possible costs seem far larger than the are. Also, even if we do take action and it turns out global warming is real, it's not the same smiley face. For example, you can download a global warming clock that says the Kyoto Protocol has cost the US $415 billion while reducing global temperatures by 0.0043 degrees. Therefore, you can deduce that reducing global temperatures by several degrees WILL reduce the global economies by many trillions in the future, EVEN IF human-caused global warming is correct. So the smiley face in the corner left is much, much smaller than the smiley face on the upper right. That would tilt our actions towards "no action" rather than "significant action".

The video is just overly simplistic even though it illustrates the concept of existential risk pretty well. It's not a new innovative argument or anything.