【单选题】

Is the world warming up? According to many reports, the answer is yes. Eleven of the hottest years since 1850 appeared between 1995 and 2006. Last year, the United Nation’s Intergovernment Panel on Climate Change (IPCC) reported the earth was about 0.75 ℃ warmer than it was in 1850. While this doesn’t sound like a lot, a small difference in average temperature can make a big difference in climate. During the last Ice Age, the planet was only about five degrees colder than now.