Alright, that's a bit of an exaggeration, but a report very quietly released by the US EPA (there's remarkably little mainstream coverage of it) has found that if emissions were cut by 56% by 2050, US GDP would grow by 80% between now and then, compared to 81% if emissions were allowed to increase on a business-as-usual basis.
And that comparison doesn't count the costs of allowing emissions to grow unabated.
It seems to me that the US is in a unique position when it comes to fighting climate change: it's the only country where taking unilateral strong action would pay off for it. That's because its emissions are such a big chunk of the global total (more than a quarter) that it can have a real impact on its own - and it faces some big costs from climate change. So if any one country should be leading on this issue, it's the US. And yet, it's the country that up to now has done the most to delay a global solution to the problem.
The EPA's analysis follows other analyses (eg, the Stern Review in the UK and recent McKinsey reports on the cost of abatement in Australia, the US, the UK and Germany) that show that strong action on climate change is compatible with strong economic growth and can be achieved at a more modest cost than is widely anticipated.