The good news is that Arctic sea ice has finally stopped melting and is beginning to refreeze, according to the National Snow and Ice Data Center (NSIDC).
However, those who are concerned about global warming should not take any comfort in this announcement. It happens about this time every year as summer comes to an end and winter prepares to settle in at the North Pole.
The bad news is that over the course of summer 2012 Arctic sea ice shrank to record low levels, an indication to James E. Hansen, a prominent NASA climate scientist, of the risks that society is running by failing to limit (atmospheric greenhouse gas) emissions.
Echoing Hansen, NSIDC scientist Dr. Julienne Stroeve told the environmental group Greenpeace in a press release, “The loss of summer sea ice has led to unusual warming of the Arctic atmosphere, that in turn impacts weather patterns in the Northern Hemisphere, that can result in persistent extreme weather such as droughts, heat waves and flooding.”
Many, but not all, scientists agree that greenhouse gas emissions are the cause of climate change. However, virtually all climate and weather experts predict that the shrinking of the Arctic ice may have a profound effect that could be felt around the world. Major questions troubling scientists and ordinary people alike are: how quickly will these effects take place and what measures are appropriate to compensate.
One of the top concerns is the melting of the Greenland ice cap.
At one point this summer, surface melt was occurring across 97 percent of the Greenland ice cap. The decline of Arctic sea ice does not contribute directly to an increase in sea level. However, because it sits on land, the melting of the Greenland ice cap has the potential to raise sea level by many feet, possibly inundating low lying areas such as New Orleans, parts of Florida and numerous other locations around the globe.
The sea is now rising at a rate of about a foot per century, but scientists like Hansen expect this rate to increase as the planet warms, putting more and more coastal settlements at risk.
Arctic sea ice has long been recognized as a sensitive climate indicator and the extent of ice coverage has shown a dramatic overall decline over the past 30 years. This year’s minimum is nearly 50 percent lower than the 1979 to 2000 average, according to the NSIDC.
The disappearance of summer ice cover replaces a white, reflective surface with a much darker ocean surface, allowing the region to trap more of the sun’s heat, which in appears to be contributing to an accelerating melt of the nearby Greenland ice cap.
“The scientific community realizes that we have a planetary emergency,” Hansen said. “It’s hard for the public to recognize this because they stick their head out the window and don’t see that much going on.