Ice Melt Accelerating, Punctuated by Unprecedented Arctic Storm: Studies

ICTMN Staff
12/31/12

Adding to the dire predictions about global warming that have come out recently, other studies focusing on the ice sheets of both poles reveal that the rate of melt has accelerated drastically over the past 20 years.

Three studies released in November and December addressed three facets of ice melt and its repercussions in Greenland and the Antarctic. The first, published in the journal Science at the end of November, found the ice melt accelerating; the second, in early December, came from the National Oceanic and Atmospheric Administration and discussed record losses of summer sea ice, as well as the early spring melt, and how they contributed to ocean rising. And the third, which came out at the end of December in the journal Geophysical Research Letters, concluded that what is known as the Great Arctic Cyclone—which hovered for days in August over the Arctic Ocean—was an unprecedented storm that may have contributed to the ice melt in that region.

Scientists were concerned not only about the accelerating melt and what it could mean for coastal cities worldwide, but also about the effects the changing dynamics could have on climate change.

Erik Ivins of California’s Jet Propulsion Laboratory was one author of a study published in Science at the end of November based on research conducted by 47 scientists and backed by the European Union, NASA, the National Science Foundation and research councils in Britain and the Netherlands, CNN reported. Comparing satellite data ranging from radar and laser readings to measurements of tiny changes in gravity around the mile-thick sheets of ice overlaying Greenland and Antarctica, the researchers found that three ice sheets—Greenland’s and two of Antarctica’s three—have lost about 237 billion metric tons over the past two decades, CNN said. That third one over eastern Antarctica grew, but not enough to make up for the loss.

“The net loss of billions of tons of ice a year added about 11 millimeters—seven-sixteenths of an inch—to global average sea levels between 1992 and 2011, about 20 percent of the increase during that time, those researchers reported,” CNN said.

"Antarctica is losing mass, but it's not losing as much mass as many of the reports had suggested," Ivins told CNN. "Greenland, on the other hand, is losing more mass today than it was in 1990 by a factor of five."

When you start talking storm surges, such a small-sounding number becomes much larger, Ivins told the Canadian Press.

“When you have 11 millimeters of increased sea level, if you compute the amount of mass that’s capable of coming on shore during storm surge, it’s a lot of mass,” he told the news agency. “Small changes in sea levels in certain places mean very big changes in the kind of protection of infrastructure you need to have in place.”

Then there was the Arctic Report Card of 2012, which summarized findings from NOAA, among other sources, to conclude that the Arctic environment has reached what it called a new normal.

“Multiple observations provide strong evidence of widespread, sustained changes driving the Arctic environmental system into a new state,” the Report Card stated.

To top it—and the year—off, in late December the study in Geophysical Research Letters revealed how two scientists in Australia had examined data from 19,625 Arctic storms and found the Great Cyclone to be the most extreme summer storm when evaluated by size, duration and other “key cyclone properties,” as the study authors termed them. Study authors Ian Simmonds and Irina Rudeva, both of the School of Earth Sciences at the University of Melbourne, said it was also the 13th most powerful storm since satellite recordkeeping began in 1979, reported the climate news site ClimateCentral.com.

The Arctic cyclone further weakened the ice, the scientists found, though they did not go so far as to say it was the cause of the acceleration.

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