> In the case that there is no man made global warming and we act, then the outcome is still good
This is the kind of statement that fuels skeptics. If the cost of "we act" exceeds the benefit, it is not "good." Skeptics are suspicious that some are using global warming to advance unrelated causes which (conveniently) require the same actions; namely, higher taxes, more regulation, bigger government.
They might further ask why, if, in your possibility space, there is natural warming, are we sure that we should act to reverse it? That is, there is a chance that a slightly warmer planet might itself have more net benefits than costs.
> 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.
You would probably think life insurance wasn't such a good bet if the premiums were 90,000 per year for a 100,000 payout. It's silly to talk about whether "climate insurance" is a good bet without assigning numbers to the premium and payout.
This is the kind of statement that fuels skeptics. If the cost of "we act" exceeds the benefit, it is not "good." Skeptics are suspicious that some are using global warming to advance unrelated causes which (conveniently) require the same actions; namely, higher taxes, more regulation, bigger government.
They might further ask why, if, in your possibility space, there is natural warming, are we sure that we should act to reverse it? That is, there is a chance that a slightly warmer planet might itself have more net benefits than costs.