The scientific community's consensus that since the industrial revolution a large number of emissions of greenhouse gases so that the average global temperature rise. The data of the United Nations said the world 100 years, average surface temperatures of 0.74 ?. And if temperature 1 ?, Australia's Great Barrier Reef coral will all die; temperature 2 ? will mean that Greenland's ice sheet melted completely, sea level rise of 7 meters; heating 6 ?, the Earth will become a hell.