Mother Nature Network: Climate change threatens lives and livelihoods as greenhouse gases build up in the atmosphere, yet the main argument for doing nothing is that doing anything would be too expensive. Some prominent skeptics even argue that laws designed to stop climate change would "destroy the economy." According to a pair of new reports, however, such warnings may be hot air. Not only is inaction even costlier than action, but action might turn out to be more affordable than most people realize. Reining in the...