wwe do see t that if youou run point-lititigation scecenarios anand you rededuce ththe amount o of greenhououse , that t you can acactually bririe icice back. yoyou can stababilie amamount of i ice loss. i if wee toto reduce ouour greenhououse , it's not going to be this runaway effect. we can stop some of these changes that are happening in the arctic, but that does meanan we're goioing o have to cocommit to reducing the amount of fossil fuels we're putttting in t the atmososphered that's the real challenge. >> most experts say fossil f fus are the leading cause of climate change. the climate change deniers often associated with the fossil fuel lobby and industry-supported think tanks downplay the connection between fossilil fuels and the warming f our planet. climate scientist michael mann on how a changing climate may affect our future. >> sometimes you''ll hear from the e itics. thehey'll say, "we demand proof that humanans are causing thihis." and my response is that t proof is reserved for alcoholic beverages andd mathematitical theorems."tt doesn't characterize how scienee works. science