The smoke from Southern California wildfires, which burned over 500,000 acres in a two-week period, drifts out over the Pacific Ocean in this NASA file satellite image from October 2007. In a vicious cycle made worse by humans, scientists now believe fires spur climate change, which in turn makes blazes bigger, more frequent and more damaging to the environment. REUTERS/NASA/Handout (SCI TECH ENVIRONMENT) FOR EDITORIAL USE ONLY. NOT FOR SALE FOR MARKETING OR ADVERTISING CAMPAIGNS