Ice melting

Polar sea ice melts each summer and reforms each winter, the freeze-thaw cycle that in the Arctic has been dramatically altered by global warming. Not only is summer sea ice shrinking rapidly in the Arctic, but so is the average thickness of sea ice. In the past, some Arctic sea ice grew to 10 feet thick over multiple years, now much of the ice has only one year of growth, making it much more susceptible to melting in the summer. Scientists project that the Arctic Ocean may be ice-free in summer in just a few decades. Lost sea ice exposes dark, open waters, dramatically shifting the ocean surface,raises regional temperatures, and changes indigenous routines.