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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White-Out: Arctic ice acts like a giant mirror that helps reflect most of the sun's rays for 6 months of the year. But as the ice melts, the Arctic is actually absorbing the sun's energy and speeding up global warming. |
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Climatic changes in the Arctic have potential consequences for the rest of the globe. Reductions in sea ice extent and snow cover cause a reduction in surface reflectivity, meaning that more energy is absorbed at the surface and less is radiated, causing further warming, which in turn leads to further melting: what scientists refer to as a 'positive feedback'.
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Melting Arctic glaciers can also contribute to sea level rise. Global average sea level rise is projected to rise between four inches and three feet (10 to 90 centimeters) during this century, primarily due to thermal expansion of the ocean and melting of glaciers and ice caps, with the rate of rise accelerating as the century progresses. Should the Greenland ice sheet melt completely, as models suggest it could, that would result in a sea level rise of about twenty-three feet (seven meters).
At the same time, melting arctic ice, combined with increased precipitation and river runoff, may lead to a freshening of the ocean in the North Atlantic, disrupting the critical salinity balance and leading to a collapse in the ocean circulation pattern that brings warm water to Europe from the tropics. As a consequence, global warming could lead to regional cooling in the Northeast Atlantic region.
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