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Any day now, the ice that covers the Arctic Ocean will shrink to its smallest area of the year. It happens every year at about this time from the cumulative seasonal effects of higher temperatures and 24-hour-a-day sunshine in the polar regions. But the loss of ice has increased over the past couple of decades.
Last year, Arctic ice covered less area than at any time since satellites began monitoring the region back in the late 1970s. This year’s ice loss won’t be quite as dramatic, but it’s still pretty significant. The graphic above shows that compared with the median ice cover from 1981-2010, this year’s loss comes out to approximately 10 times the land area of Pennsylvania. And while each year isn’t necessarily less icy than the year before, the downward trend is clear — and the plunge is happening faster than the majority of computer models predicted.
There is a natural cycle of melting and freezing that happens every year. However, the loss over recent years is starting to alter the natural melting for the worse – creating a vicious cycle. When the ice shrinks, its bright, white, reflective surface is replaced by darker ocean. The darker ocean absorbs heat and makes it more difficult for the ice to refreeze in winter. In recent years, the winter ice has also gotten thinner which makes it more prone to melting the next season. Finally, more open water means winds and ocean currents can push more ice out into the North Atlantic where storms can break it up, further reducing the amount of sea ice.
Credit: National Snow & Ice Data Center (NSIDC)
Nobody knows when the summer in the Arctic will be totally ice-free, but on the basis of observed trends and computer models it could happen within just a few decades—or even less. That will make polar bears unhappy, but it could affect us, too. Some climate scientists think that the warming Arctic has altered the jet stream in ways that are bringing us more extreme weather events, while others seem not to detect as strong a linkage with extremes. That’s an area of active research at this point, but it is a fact that the Arctic is warming faster than any other part of the globe—and it’s not crazy to think that this large change just has to have an effect on the rest of the planet.