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In the Arctic Ocean, sea ice has melted dramatically this summer, topping the previous record. And the melting may continue for a few more days before cooler weather takes hold.
NPR's Richard Harris has this story exploring what's driving this unprecedented loss of ice.
RICHARD HARRIS, BYLINE: Some of the sea ice covering the Arctic Ocean always melts away during the summertime. Usually, about half of it disappears. But this year, three quarters of the ice has melted away, setting a dramatic new benchmark.
TED SCAMBOS: It didn't just touch the record, it really drove right through it.
HARRIS: Ted Scambos at the National Snow and Ice Data Center at the University of Colorado says the previous record was set in 2007. This year, the additional area that melted is the size of Texas.
SCAMBOS: I would say that it's been a few thousand years since we've seen the Arctic this open.
HARRIS: The Arctic ice has been in decline for several decades now. Scambos says conditions in the Arctic this summer were a bit out of the ordinary but nothing dramatic.
SCAMBOS: We saw a very early onset to the melt season, about 10 days to two weeks earlier than usual.
HARRIS: And at the summer solstice, when the sun was at its highest, the skies were mostly clear, allowing more sunlight to heat the ocean and melt the ice.
SCAMBOS: So you really got off to a fast start in June. And by August, we really saw an astonishing rate of decline, mostly because the ice was very thin and simply melted out after three months of warm weather.
HARRIS: This melting trend is accelerating because the ice in the Arctic is getting thinner as the region warms. A few decades ago, lots of ice in the Arctic was 10 feet thick and would clump up as the wind pushed it around the northern coastlines.
SCAMBOS: Now, that ice used to survive and stir around in the Arctic for decades and create a very thick mass that could survive a few warm summers. We don't get that anymore. We get persistently warm summers that have gradually eroded the ice cover until it's now very, very thin and not stable.
JENNIFER FRANCIS: It doesn't take a scientist to look at what's happened to the Arctic sea ice and know that something really huge is happening in the climate system.
HARRIS: Jennifer Francis is at Rutgers University. She says the effects of this change won't be confined to the Arctic. Polar bears and walruses, which depend on floating ice, may feel the change most acutely, but changes in the far north are likely to affect our weather as well. She says Arctic warming changes the way waves of weather flow across the Northern Hemisphere.
FRANCIS: Those waves that the storms are associated with are tending to move more slowly. What this means is that it increases the probability of some kinds of extreme weather that are related to weather conditions that hang around a long time.
HARRIS: Think of those slow-moving snowstorms that buried the East Coast a couple of winters ago. She expects some extreme weather this coming winter, though there's no telling whether it will hit us or someone on the other side of the globe. Scientists still make projections for when the Arctic could be completely free of summer ice, and those mostly point to the 2030s or beyond. But Ted Scambos at the National Snow and Ice Data Center says it's a mistake to pay too much attention to the date when the summertime Arctic will be completely free of ice.
SCAMBOS: Nobody is going to care that there's a small patch of, say, a million or two million square kilometers in the Arctic because it'll be off to one side. And if you're interested in access to the Arctic, or if you're interested in the climate change impacts from an open Arctic in summer, they're all going to be there big time.
HARRIS: In fact, we're feeling those effects already. But even in extremely warm years like this one, ice is still a force to contend with. Some of the key navigational passages never did open up this summer, and a chunk of ice 30 miles long is heading toward Shell Oil's drilling site in the Arctic Ocean. That has forced the company to move its rig out of the way just a day after it started drilling. Richard Harris, NPR News. Transcript provided by NPR, Copyright National Public Radio.