The trouble with global warming, at this point, is its sheer size and momentum. It's no longer a future threat, but a very present crisis: the best science tells us that 350 ppm co2 is the most we can safely have in the atmosphere. We're already past that--at 387 and rising--which is why the Arctic is melting, the boreal forest succumbing to pests, Australia on fire. That means we're not going to solve this one factory, one product, one light bulb at a time. Only large scale political action will do the trick, forcing our leaders into the kind of treaties that will reset the price of carbon and really drive change...