According to Krugman's excellent summary of the consensus amongst economists is that avoiding catastrophic rapid climate change would cost 0.03 to 0.09 percent point of growth per year until 2050. In other words, the annual to 2050 would be 2.31 percent, instead of 2.4 percent. That is very small indeed. Put another way, it would cost 775$ per household over 40 years, which is about 20$/year. And at 2.66 persons per household on average, solving the problem cost a whole 7.26$/year. It's about the price of the Starbucks latte you took Jan 17st, plus the price of the one from Aug 23rd.
Let's do a cost/benefit analysis. If we maintain the status-quo, and proceed as usual and burn all the coal available on this planet, the temperature goes up by 11F (see the question-and-answer section at the end of the talk.) New York becomes Mississippi and Mississippi becomes unlivable. If we burn all the coal, we return to the temperature on the planet before the coal was made, 55 millions year ago. It was the time of the Paleocene-Eocene Thermal Maximum, a "slow" event, with a gradual warming spread over 20'000 years time, that nevertheless resulted in a mass extinction.
Meanwhile, we human have sufficient coal-fire power plants deployed to get that kind of change done in 100 years. Go us!
So, to complete this cost/benefit analysis, I ask you, how much is your planet worth?