Abrupt climate change could render parts of Europe unlivable by 2020, and reduce Earth to a world of warring states, according to a Pentagon study. Intense global warming could melt polar ice and swell the oceans with fresh water, altering sea currents that warm the Northern hemisphere. America would suffer economic damage but avoid catastrophe, while Europes climate would chill and become more like Siberias. A cold and hungry China would erupt in civil war. The authors of the report, Imagining the Unthinkable, said they were not predicting that such climate changes would actually happen. Rather, they wanted to dramatize the impact climate change could have on society if we are unprepared for it.