Another flaw in his approach is that Column A Row1 will have the same outcome as Column B Row2 if the warming is being caused by processes other than our own, which is the case.

>Now this is a really clever approach, imo. Very worth watching:
>
>http://www.youtube.com/watch?v=bDsIFspVzfI
>
>
>Update: I would say there might be one possible flaw and that is that one would need to apply some sort of probability to the various squares. Sticking with his 2 columns; what if the probability of column B - bottom square is infinitesimally small. What if GCC is occurring (row 2) and we do nothing (column 2) but the extreme outcome case he presents is extremely unlikely and that a much milder outcome is most likely. Then it would not make sense to pick column 2 anymore. This would be the classic risk vs. cost of protection trade-off. If one argues that the potential consequences are so catastrophic that even a small probability event needs to be catered for then we could imagine a very long list of such events that would need to be attended to and then we would end up spending ourselves into oblivion.

bDsIFspVzfI