Pascal's wager applied to climate change (Part 2)

My previous post was, in a way, too simplified, by asking only whether or not climate change is real. Either climate change is real or it is not. If it is real, then it is either caused (and can be affected by) human activity or it isn't. If human activity does have an effect on the climate, then either drastically reducing carbon emissions is the only way climate change could be halted or reversed, or else other, less drastic methods would be sufficient. So, here's the new grid:

Action	A. If climate change is real and is caused by human activity and can only be reversed or halted by drastically reducing CO2 emissions	B. If climate change is real and is caused by human activity but can be reversed or halted by a variety of less drastic methods	C. If climate change is real but is NOT caused by human activity	D. If the climate is not changing
1. Do nothing	Global disaster	Global disaster	(Eventual but inevitable) global disaster	No change
2. Use a variety of less drastic methods to reduce our environmental impact	Global disaster (perhaps delayed slightly)	(Hopefully) disaster averted, or reduced Pollution reduced	(Eventual but inevitable) global disaster Pollution reduced	Pollution reduced
3. Drastically reduce CO2 emissions (+ other methods)	(Hopefully) disaster averted, or reduced Possible economic hardship.	Pollution reduced Some unnecessary spending	(Eventual but inevitable) global disaster Pollution reduced Some unnecessary spending	Pollution reduced Some unnecessary spending Some unnecessary fear

See also my responses to Bruce's comments >