Historically, sea ice forms every winter across the top of the planet, and covers much of the Arctic Ocean. Every summer, the ice melts a bit and retreats, only to repeat the cycle again. But since the 1980s, the Arctic sea ice is melting at a rate far faster than anyone thought, and it is already wildly, and perhaps permanently, changing the region, and the planet.
Scientists say the rapidly melting ice is raising sea level, erasing food sources and habitat, and causing waves and wind so strong they are biting off chunks of coastlines in Alaska, Canada and elsewhere.
"In general, we are losing tremendous amounts of ice from everywhere on the planet," said Tom Wagner, program manager for NASA's cryosphere research. It is happening in "Greenland, Antarctica, the small glaciers and ice caps of Alaska and Canada. And all that stuff is raising sea levels." We even appear to be losing ice in the Himalaya mountain range, he added.
Click ahead to view NASA's graphic renderings of the sea ice levels at various times. Pictured here is 1988.