vikings
long ago some people found this nice big green island. it was a great place to live. they named it greenland. and they grew grapes and made wine. then they got drunk, built boats, and sailed off to rape and pillage their neighbors. or something like that. it was great fun! but nothing good ever lasts. something happened. they started to grow ice. which i think was an extreme tactical error. and no fun at all. though i think their neighbors were happier. if a bit colder. the seasonal temperature average changed by a mere 1 degree celsius. pretty amazing that such a small change can have such a dramatic affect. the (current) predicted temperature increase for this century is some 3 to 5 degrees celsius. that should send a chill down your spine. err... something.