Scott Adams has a nice piece up on the difficulty of making heads or tails of the climate change debate which covers the bases well, but I think misses a subtle point. I'm going to take a big risk and comment on this early in the morning with only 2 cups of coffee in me.
The climate argument is in reality, 2 questions, one fairly trivial, and the other much weightier in terms of costs and cultural impacts.
Question 1 is "Does human activity have an impact on the global climate? The answer is a no brainer; Of course it does. No one argues differently. You get the same response to asking if there's Uranium in your drinking water. Any civil engineer will tell you yes, but then go on to explain just how much. That last bit is the important part and contains the answer to the second question.
2. a)How much influence does human activity actually have on the global climate, and b) what, if anything, should be done and c) at what cost?
If you are a hard core climatista, you always ask the first question first, and use the affirmative answer to force your agenda as the answer to the second question without actually having to discuss it. Ralph Nader used this approach successfully against General Motors arguing that the Corvair's suspension system was not up to the standards of say Porsche, and that when the older ones were driven like a Porsche, they spun out, sometimes with fatal consequences. By the time the suit was settled, the Corvair had been upgraded to the point that it was widely called the "poor man's Porsche" but too late and a car that GM marketed as a family economy car was discontinued.
Re: Climate, question 2a: It would appear that human activity has very little impact on the big climate swings which seem to happen on a regular basis whether we're here or not.
The answer to 2b, what should be done, is answered by 2a, which suggests that not all that much actually needs to be done. Certainly some local areas need to be brought up to code as it were, since the smog from China is detectable here in the US and even the Chinese admit that something urgently needs to be done. We have the technology to burn coal relatively cleanly, and the Chinese could insist that this be implemented in all future coal burning plants and added to the existing ones as opportunity permits.
2c: We have already implemented the most cost-effective solutions like scrubbers on coal plants and conversion to natural gas, and are now debating the need for the less cost effective ones like subsidy hogs wind and solar while pulling off the table the best ones like advanced nuclear as being politically incorrect.
Changing peoples minds is very difficult, but not completely impossible. When conditions get harsh enough, the most hardened greenie will adjust his world view to allow the thermostat to be turned up or at least to toss a few more dried cow chips onto the fire. Perhaps sending some of them to a climate science pilot project installation in northern Saskatchewan, with heat and power supplied by burning freeze dried caribou chips would help.
Believe it or not, the EPA is supposed to evaluate its rules and regulations in terms of costs vs benefits, and keep the impact on the good side of that curve. To date, I've never heard of them actually doing this as forcing regulations on the public is beneficial to the continued growth of the EPA and thus over rides any cost to the public. Trumps appointment of a skeptic to head the EPA may help here but the resistance within the agency will run all the way to the bottom.