As ice melts, heat builds up!

The amount of sea ice in the Arctic has fallen to the lowest level on record, a confirmation of the drastic warming in the region and a likely harbinger of larger changes to come. Satellites tracking the extent of the sea ice found over the weekend that it covered about 1.58 million square miles, or less than 30 percent of the Arctic Ocean’s surface, scientists said. The National Snow and Ice Data Center, a government-sponsored research agency in Boulder, Colo., announced the findings on Monday in collaboration with NASA.

While the melting of sea ice does not raise global sea levels, because the floating ice is already displacing its weight in seawater, the sharp warming that is causing the sea ice to melt also threatens land ice, notably the Greenland ice sheet, which is melting at an increasing rate. Melting land ice does raise sea levels.

Already, the reduction in sea ice is altering weather patterns in the Arctic region, and perhaps beyond. It is putting stress on the ecology of the region and causing rapid erosion of shorelines that are now exposed to more vigorous waves. It has consequences for weather in the Northern Hemisphere’s middle latitudes, including in the United States. Research suggests that air circulation patterns are being altered in a way that favors more extremes, like heat waves and droughts.

The melting offers easier access to oil and other mineral deposits. Witness the rush by all nations to stake claims and begin mineral exploration in the Arctic.

The average temperature of the region is rising more than twice as fast as that of the earth as a whole, confirming a prediction first made in 1896: that increasing levels of carbon dioxide from the burning of fossil fuels would have an especially large impact in the Arctic. One reason is that the white surface of the ice reflects a great deal of sunlight back to space, but the darker water and land exposed when the ice melts absorb more heat from the sun, which in turns leads to additional melting, more sunlight absorption and so on — a feedback loop that scientists call Arctic amplification. Anybody's guess what will happen as weather patterns turn haywire.