dr. james wilder studies the polar bear population in the bufrtd sea near barter island.e says these bears have been coming to these shores for thousands of years but climate change has changed their behavior. >> polar bears are showing up earlier. they used to show up in the beginning of september. now we see them showing up in the late july, august, and staying for longer and that seems to be correlated with the availability of sea ice. so if sea ice melts earlier, then bears will come to shore sooner. and if it forms later in the fall then itting agreg yates on the coast for longer periods of time. >> it's not good for us. we're used to ice out there hunting the whale. >> reporter: for the people of kaktovik their way of life is at risk as well. >> this is the road i grew up on, the main road. >> reporter: marie rexford is a witness to the changes wrought by rising temperatures. >> good attraction for all the tourists. to us they're a nuisance. they can smell your good food anywhere. they have broken down our door to our cellars. >> reporter: for centuries residents st