Green House Gases

I'm no scientist. Still, I wonder about the claims that scientists make about global warming. I just want to state that the world is constantly changing. Take a moment to think back to the idea of Pangea. If green house gases did not change, but stayed the same would our world have evolved as it did? In this article: http://news.yahoo.com/s/ap/20071123/ap_on_sc/greenhouse_gases, The U.N. Intergovernmental Panel on Climate Change predicts that, "by 2020, 75 million to 250 million people in Africa will suffer water shortages, residents of Asia's large cities will be at great risk of river and coastal flooding, Europeans can expect extensive species loss, and North Americans will experience longer and hotter heat waves and greater competition for water." Isn't this change repetitive? I feel that this change is here for a reason. Global warming is just natures way of controling population. (That is all population, including humans!) this just proves that life is about survival of the fitist and species of all kinds will have to adapt to survive. After all, there is not enough room on the earth for every animal. (I don't think I would like it if Dinosaurs were still around!) So I leave you with this...Maybe green houses gases and global warming serve a big purpose and are not so bad.