There's a massive meltdown happening in the Arctic - and it's not just polar bears who will feel the effects.
Since satellite monitoring began in 1979, sea ice in the Arctic has been on the decline, shrinking by about 10 to 12 percent per decade. In the summer of 2007, Arctic sea ice cover shrank to an unprecedented low.
At this rate, researchers project that the Arctic may experience a summer completely devoid of ice by the end of the century.
What's causing the thaw? A major culprit is greenhouse gas emissions from human activities, like burning fossil fuels. Greenhouse gases trap thermal energy that would otherwise dissipate into space. This results in warmer air temperatures which prevent Arctic ice from freezing in the fall and cause the ice to melt earlier in the spring.
Snow and ice reflect sunlight and help to keep polar sea temperatures cool, but with less of the sea covered by ice and snow, the ocean absorbs more heat from the sun - raising the water temperature and making it even harder for ice to form.
Shrinking ice masses disrupt the life cycles of Arctic animals like seals, walruses, polar bears and seabirds, which depend on ice for places to travel, hunt, and raise young. But a warming Arctic affects the rest of the globe, too. Melting ice means rising sea levels, which can lead to storm surges, flooding and erosion, disrupting delicate coastal ecosystems as well as human communities. A cold Arctic also is essential for the system of wind and ocean currents that regulates Earth's climate.
Computer models suggest that, if Arctic warming is curbed, sea ice can recover in the future. That leaves it up to humans to keep climate change in check.