by Kirstin McPolin
The Quick Facts: The science of global warming has been debated for decades. While there are still some scientists, businesses and politicians that believe global warming is not driven by human influences, but is instead simply due to natural climate variability, the vast majority of scientists agree that global warming is a reality fueled by human activities. The IPCC’s 2007 Fourth Assessment Report-the work of more than 2,500 scientists from 130 countries and research conducted over six years -finds that scientists are “virtually certain” (99% sure) that human use of fossil fuels is contributing to global warming. Evidence has been building that the Earth is getting hotter with NASA reporting that the hottest years were (in order with hottest first): 2005, 1998, 2002, 2003 and 2004. The IPCC predicts an average world temperature increase of 2.7 to 8.1 degrees by 2100; more heat waves; a potential sea level rise of up to 20 inches by 2100; an average 6 inches or less annual rainfall for the U.S.’s South West, and an annual average 6 inches more rainfall for the U.S.’s North East; and 50 more (than average) days that never fall below 32 degrees for the U.S.’s Pacific North West.