Global Warming is Happening Now
Scientists are no longer telling us what will happen, they are telling us what is happening.
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Shifting Sea Ice : Summer ushers in warmer temperatures in the Arctic, and begins breaking and melting the sea ice. But in recent years, temeratures have risen, and sea ice is melting earlier and forming later, making survival for polarbears who depend on the ice to hunt, precarious at best. |
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Sea ice (literally, the frozen surface of the sea) is an essential element of the Arctic marine ecosystem. On its underside grows algae which support the entire food chain. It provides shelter for species such as arctic cod, and is an essential habitat for migratory birds, for seals and walruses, for polar bears, and for Native peoples.
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However, sea ice is in retreat throughout the Arctic. Over the past thirty years, annual average sea ice extent has decreased by about 8%, or approximately 386,000 square miles (one million square kilometers), an area the size of Texas and Arizona combined. Additional declines of 10-50% in annual average sea-ice extent are projected by 2100, with summer sea ice declines projected to be around 50%, and some models predicting near-complete disappearance of summer sea ice.
The remaining sea ice is also thinner. Reductions in average thickness levels across the Arctic are estimated at 10-15%, with some areas showing reductions of up to 40% between the 1960s and late 1990s.
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