Global warming. If CO2 levels keep rising as they are, global temperatures will be 6 degrees warmer by the end of the century, and recent evidence suggests that number may now be conservative. It will result in massive food shortages and will reduce humanity to a few bands struggling for survival at the poles according to this article: http://www.int.iol.co.za/index.php?set_id=1&click_id=31&art_id=vn20070204092500226C199716
A long CBC podcast which highlights the issues which will result out of global warming, which will mostly be wars over dwindling food supplies, is here:
http://www.cbc.ca/ideas/features/climate-wars/index.html
I don't know if you can watch it if you're outside of Canada.
Also, I find it very worrisome that people make joking and speculative threads about the end of the world when the world's climate scientists know exactly what will result in the end of humanity, they look at the numbers every day, and are in a state of panic. It suggests that most people have no idea about what's going on outside their little part of the industrialised world, the things which are going to get very close to their nice, perfect little cities VERY quickly. (Ok, a few decades, it's still pretty damn fast.)
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Nukes are actually pretty reasonable though because wars that will result from reduced food because of less water and more people
*edit*
Actually, could someone please tell me if you can in fact watch the CBC podcast if you're outside of Canada? I'm curious if they're preventing people from other countries from watching, they are with other CBC media.
