Hunterbrum, Global Warming isn't limited to the US and the degree of impact on civilization. I believe one good example would be Hurricane Catalina that hit the coast of Brazil last year. That hurricane should be the most historic Hurricane in history b/c its the first hurricane ever to hit South America! I should say, the main issue isn't hurricanes and maybe it is more of a subject people stress over b/c of Hurricane Katrina but it is a factor. Onereason Katrina became so strong was b/c of the above avg. water temp in the Gulf of Mexico. If you need proof of whether humans are involved just look at the history since the Industrial Revolution and see the correlation of CO2 levels compared to temperature levels. Scientists in Antartica take Ice Core samples that go back thousands of years and can determine by the use of isotopes the amount of CO2 in the ice and compare that year to year to how thick the ice is. It is like the rings of a tree.NASA came out and said that the 5 hottest years of this century were 2005, 1998, 2002, 2003, 2004. Is it just a coincidence that we are putting off more CO2 emissions ever from fossil fuels and the temp is rising?