Arctic Ice Melt Linked to Chilly Spring

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The Arctic sea ice has reached its winter maximum for the year -- the sixth lowest maximum on record -- at the same time that weird, chilly spring weather in the northern hemisphere has many people wondering if there is a connection to the Arctic changes.

The answer is yes and no, according to scientists monitoring the ice as well as those trying to figure out how it affects the rest of the planet.

The sea ice maximum was reached on March 15, and despite being the high point of sea ice for the year, its lower than average extent and some remarkable mid-winter cracking of the sea ice has researchers concerned.

"There is cracking every year when the ice is pushed by the winds and currents," said Walter Meier, of the National Snow and Ice Data Center. "But this was particularly extreme. Qualitatively, this seems like the biggest."

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Instead of a few narrow cracks, powerful winter storms led to a number of large cracks, hundreds of meters wide, that stretched all across the Arctic.

The cracks quickly froze shut, but that refrozen ice would have to be thinner than the ice that cracked, which itself was just first-year ice that started building up in September or October. The resulting patched together ice sheet would naturally be more vulnerable to melting in the summer.

As for why the extreme cracking occurred at all, that traces back to the summer melting, which has claimed more and more of the thick, crack resistant, multi-year ice, Meier explained.

The graphic shows the extent of the area of the Arctic ocean in winter with at least 15% sea ice coverage.
National Snow and Ice Data Center, Boulder, Co.

All these ice troubles do, indeed, have weather effects well beyond the range of polar bears.

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Research is underway to nail down the details, but it appears that by warming the Arctic and lessening the pressure and temperature differences between the Arctic and the temperate latitudes, two big changes can happen to make weather much worse in North America and Eurasia.

The first change is the slowing of westerly winds, which keep weather systems moving from west to east, explained climate researcher Steve Vavrus of the University of Wisconsin, who is modeling the effects of less sea ice on weather. That means if a snow storm or heat wave strikes, it will stick around longer, worsening its effects.

The second change is that the jet stream takes on more of a meandering loop. That means Arctic air can dip south with those loops -- chilling temperatures. The dipping cold air also then has more chances to come in contact with much warmer, wetter air to the south. The result can be violent storms and lots of tornadoes.

"You can't say it about one storm or one season," Vavrus said who is working closely with researcher Jennifer Francis of Rutgers University. "But what we are seeing this year is the kind of change that we expect."