We've heard a lot about melting ice in the Arctic this summer, and we're likely to hear more. It takes a long time for polar ice to start melting and a long time for it to return, so the 2012 melt will continue for another month or so. That means -- almost certainly -- some new climate records. And with no sign of serious efforts to stop or slow the human contribution to climate change, there will be more records in the future.
|A satellite image of the Northwest Passage, taken August 3, 2012, |
shows large areas of open water.
Photo credit: NASA Earth Observatory images by Jesse Allen
Here are a few of the stories so far this summer:
Just a few days ago, scientists from the European Space Agency reported that sea ice in the Arctic is melting far faster than anyone predicted. Based on information from a satellite that measures the thickness of the ice, they estimate that 900 cubic kilometres of ice have disappeared every year since 2004. At that rate, they say, it could be as little as ten years until the day when a satellite image shows no ice at all in the Arctic Ocean at the peak of the summer melt.
Earlier this month, a giant cyclone raged over the Arctic Ocean. Storms are common at this time of year, but the researchers studying them said this was the biggest they had seen. The winds churned the ocean, breaking up the ice floes and making them more susceptible to melting.
In mid-July, a wash of warm air over Greenland triggered melting across 97 percent of the island's massive ice sheet. The last time this happened was in 1889. Scientists don't know if the melt this time is related to climate change, but they do know global warming is causing Greenland's glaciers to thin and chunks to break off, forming massive icebergs.
Does any of it matter? The quick answer is, yes. Whole ecosystems depend on arctic sea ice, from microscopic, single-celled organisms to polar bears. As the ice retreats, the open ocean absorbs more heat, warming the atmosphere above it and speeding up global warming. And melting of the fresh water locked up in Greenland's ice sheets would cause sea levels to rise around the world.
For a less quick, more detailed answer, and lots more about climate change, try some of these sites:
Arctic Sea Ice News & Analysis, from the United States' National Snow & Ice Data Center
RealClimate: Climate science from climate scientists
ClimateSight: an excellent blog by a young Canadian climate researcher