> If the cost of "we act" exceeds the benefit, it is not "good." I think the point is that of the four possible outcomes (in order of costs: no action and no c

> If the cost of "we act" exceeds the benefit, it is not "good." I think the point is that of the four possible outcomes (in order of costs: no action and no climate change, action and climate change is real, action but no climate change, climate change is real but no action), this is the second worst outcome. All other things being equal it really comes down to a risk assessment. Yes - this, the third option, would be seriously painful from an economic point of view. But the fourth, which is what the overwhelming majority of climate science tells me you're proposing, would be an unmitigated catastrophe. We're being asked to make a bet. My bet goes on spending the money for the same reason I have life and income protection insurance. I don't think it's a waste of money if I fail to die prematurely or incur serious injury. Plus, in real terms, the cost is similar.