Plot: Can emerging technology defeat global warming? The United States has invested tens of billions of dollars in clean energy projects as our leaders try to save our crumbling economy and our poisoned planet in one bold, green stroke. Are we finally on the brink of a green-energy "power surge," or is it all a case of too little, too late? From solar panel factories in China to a carbon capture-and-storage facility in the Sahara desert to massive wind and solar installations in the United States, NOVA travels the globe to reveal the surprising technologies that just might turn back the clock on climate change