A report by economist Sir Nicholas Stern suggests that global warming could shrink the global economy by 20%, but taking action now would cost just 1% of global gross domestic product. http://news.bbc.co.uk/1/hi/business/6096084.stm Review summary: http://news.bbc.co.uk/1/shared/bsp/hi/pdfs/30_10_06_exec_sum.pdf The report warns that if no action is taken: a.. Floods from rising sea levels could displace up to 100 million people b.. Melting glaciers could cause water shortages for 1 in 6 of the world's population c.. Wildlife will be harmed; at worst up to 40% of species could become extinct d.. Droughts may create tens or even hundreds of millions of "climate refugees" Still not convinced...