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Climate: Arctic and Antarctic ice melt are accelerating

Greenland and Antarctica are now losing more than three times as much ice as they were in the 1990s

Antarctic sea ice may be growing, but ice sheets on the frozen continent’s edge are losing mass and contributing to sea-level rise. Bob Berwyn photo.

By Summit Voice

SUMMIT COUNTY — Climate scientists say they’re closer to pinpointing exactly how much of Greenland’s and Antarctica’s ice is melting, and after producing the most accurate assessment of ice losses to-date, a team of satellite experts say they’ve ended 20 years of uncertainty about how much that melting ice contributes to global sea level rise.

According to the landmark study, published on Nov. 30 in the journal Science, the that melting has contributed 11.1 millimeters to global sea levels since 1992. This amounts to 20 percent of all sea level rise during the survey period. About two thirds of the ice loss was from Greenland, and the remainder was from Antarctica.

Together, Greenland and Antarctica are now losing more than three times as much ice (equivalent to 0.95 mm of sea level rise per year) as they were in the 1990s (equivalent to 0.27 mm of sea level rise per year). The rate of melting increased dramatically in the late 1990s. Continue reading

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Climate: Arctic sea passage along Russian coast thaws early

Northeast Passage expected to open in early summer this year; route along Russian coast offers a 4,000 mile shortcut between Europe and Asia

The EM-Bird over thin ice: The picture was taken with a camera mounted inside the MI-8 helicopter. It shows the EM-Bird 15 meters above a layer of rafted thin ice, approximately 10 centimeters thick. Photo: Thomas Krumpen, Alfred Wegener Institute.

By Summit Voice

SUMMIT COUNTY — After a series of measurement flights over the Laptev Sea, scientists with the Alfred Wegener Institute for Polar and Marine Research are predicting that the Northeast Pass, an Arctic Ocean shortcut along the north coast of Russia, will once again be ice-free and passable to ships by early summer.

The Laptev Sea is known as in ice factory, but at the end of the winter, researchers discovered large areas of thin ice that won’t survive the summer melting season.

“These results were a great surprise to us,” said expedition member Dr. Thomas Krumpen.

In previous measurements in the winter of 2007-2008 the ice in the same area had been up to one meter thicker. Krumpen said the difference is mainly due to wind. Continue reading

Global warming: Tracking permafrost meltdown

Satellite measurements by the European Space Agency suggest that a permafrost meltdown may be starting.

European satellite monitoring measuring changes in permafrost regions

By Summit Voice

SUMMIT COUNTY —One of the biggest concerns related to global warming is that rapid permafrost melting in northern latitudes could release a massive surge of additional carbon dioxide into the atmosphere.

It’s not clear whether such a meltdown tipping point is imminent, but the satellite record suggests the process has started, according to researchers who gathered recently at a permafrost workshop at the Alfred Wegener Institute in Potsdam, Germany.

Research presented at the conference indicates that satellites are seeing changes in land surfaces in high detail at northern latitudes, suggesting thawing permafrost. Data from satellite monitoring by the European Space Agency was a key part of the conference findings.

Permafrost is ground that remains at or below 32 degrees for at least two consecutive years and usually appears in areas at high latitudes such as Alaska, Siberia and Northern Scandinavia, or at high altitudes like the Andes, Himalayas and the Alps. Continue reading

Global warming: Lake ecoysytems at risk

Satellite data in a new study on global warming shows that some major lakes around the world are heating at a rate of up to 1.8 degrees per decade.

Study provides independent source for assessing global warming impacts

By Bob Berwyn

SUMMIT COUNTY — A comprehensive study of global satellite data shows surface temperatures of large lakes around the planet warmed significantly in the past 25 years in response to climate change.

Researchers Philipp Schneider and Simon Hook of NASA’s Jet Propulsion Laboratory in Pasadena, Calif., used satellite data to measure the surface temperatures of 167 large lakes worldwide, finding an average warming of 0.81 degrees per decade, with some lakes warming as much as 1.8 degrees Fahrenheit per decade.

The warming trend spans the globe, but is most pronounced in the mid- to high-latitudes of the Northern Hemisphere. Warming was weaker in the tropics and in the mid-latitudes of the Southern Hemisphere. That’s consistent with what’s expected based on most existing climate models, said Hook. Continue reading

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