"In the course of a 17-year experiment on more than 1 million plants, scientists put future global warming to a real world test — growing California flowers and grasslands with extra heat, carbon dioxide and nitrogen to mimic a not-so-distant, hotter future. The results, simulating a post-2050 world, aren't pretty. And they contradict those who insist that because plants like carbon dioxide — the main heat-trapping gas spewed by the burning of fossil fuels — climate change isn't so bad, and will result in a greener Earth."