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Arctic Report Card: Dark Times Ahead

Decreasing snow amounts may be pushing Arctic fox populations in Europe toward extinction

NOAA

Conditions in the Arctic are slipping rapidly from bad to worse as the pace of climate change accelerates in that region. That’s the message from an annual environmental assessment of the far North, released on Wednesday.

“Conditions in the Arctic are changing in both expected and sometimes surprising ways,” said Jane Lubchenco, head of the National Oceanic and Atmospheric Administration. The changes are having an impact far beyond the far North, she added. “What happens in the Arctic doesn’t always stay in the Arctic. We’re seeing Arctic changes that affect weather patterns in the US,” Lubchenco said at a meeting of the American Geophysical Union in San Francisco, where the Arctic Report Card was previewed. The online report was written by 114 scientists from 15 countries.

According to the report, the Arctic broke a string of environmental records this past year. The summertime sea ice pack was the smallest ever seen. The amount of Northern Hemisphere snow in June hit the lowest mark on record. Virtually the entire Greenland Ice Cap showed some evidence of surface melting for the first time in observations going back to 1979. And permafrost temperatures on the North Slope of Alaska topped previous highs, said Martin O. Jeffries, a co-editor of the Arctic report and the Arctic science advisor at the Office of Naval Research. “If we’re not there already, we’re surely on the verge of seeing a new Arctic,” he said.

The widespread reduction in snow and ice cover in summertime has darkened the ocean surface and land in the Arctic, allowing it to absorb more sunlight, which leads to enhanced warming. “The Arctic is one of Earth’s mirrors and that mirror is breaking,” said Donald Perovich, an Arctic researcher at Dartmouth College, who participated in the report.

The darkening of the surface creates a positive feedback that explains why the Arctic is warming twice as quickly as lower latitudes, said Jeffries. “This is what we call the Arctic amplification of global warming, a phenomenon that was predicted 30 years ago, which we’re now seeing happening in a significant way.”

The changes are putting stress on some creatures, including Arctic foxes in Scandinavia and nearby regions. The European population has crashed in recent years; and with only 200 individuals left, it is in danger of extinction, according to the report, which blames disruptions in the population of rodents. Lemming numbers have dropped in some regions, and scientists have suggested that reduced snow cover may be implicated, said Jeffries.

The Arctic assessment comes out a week after a report that documented accelerated melting of ice sheets in Greenland and Antarctica.

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    Michael Edward McNeil said:

    The Arctic assessment comes out a week after a report that documented accelerated melting of ice sheets in Greenland and Antarctica .

    The Nature news piece referred to is titled “Grim picture of polar ice-sheet loss”, subheaded: “Antarctica and Greenland are rapidly losing their ice sheets because of climate change, says a comprehensive review.”

    But is the ice-sheet-loss picture across Greenland and Antarctica really as imminently “grim” as the title at least suggests, and are those huge subcontinental and continental regions really “rapidly losing their ice sheets” (according to any sensible definition of “rapidly”)?

    Drawing from the indicated Science article , we learn that, “Between 1992 and 2011, the ice sheets of Greenland, East Antarctica, West Antarctica, and the Antarctic Peninsula changed in mass by –142 ± 49, +14 ± 43, –65 ± 26, and –20 ± 14 gigatonnes year^−1, respectively.”

    Thus, ignoring plus-minus uncertainty, the two decadal (1992-2011) rate of glacial melt across Greenland and Antarctica (incorporating 99% of all the world’s glacial ice) adds up to a total of –213 gigatons (10^9 or billions of metric tons) of ice gain (i.e. loss) per year. Sounds like a very big number, doesn’t it?

    Let’s do something that these published AGW research articles never seem to find at all interesting: express the finding in terms of how long it will take at that instantaneous rate to melt all of Greenland and Antarctica’s glacial ice. Granted the melt rate appears to be accelerating, yet even so, considering the overall time scale ought to tell us something interesting about the scope of the problem.

    To arrive at this figure, one must compare the measured melt rate with the amount of glacial and ice-cap ice presently resident in Greenland and Antarctica. Referring to the Satellite Image Atlas of Glaciers of the World (U.S. Geological Survey Professional Paper 1386-B) for this information, we see (page 6, pdf) that:

    3.01 × 10^7 km^3 Antarctica’s total ice volume

    2.60 × 10^6 km^3 Greenland’s principal “Inland Ice”

    2.00 × 10^4 km^3 Greenland’s peripheral glacial ice

    The total glacial and ice-cap ice divided between these two continental domains is therefore 3.272 × 10^7 km^3, or about 33,000,000 cubic kilometers.

    So how long would all that ice last?

    3.3 × 10^7 km^3 (total ice volume in cubic km)

    = 3.3 × 10^22 cm^3 (same in cubic centimeters)

    = 3.0 × 10^22 g (total ice mass in grams — see note)

    = 3.0 × 10^16 t (same in metric tons)

    = 3.0 × 10^7 Gt (same in gigatons)

    [Ice I (which we’ll assume all of the ice in Greenland and Antarctica is in the form of) is about 9% lighter than water.]

    There are thus some 30 million gigatons of glacial ice in Greenland and Antarctica. You know, that’s an even much larger number.

    Dividing by (what we now see as a measly) 213 gigatons of glacial ice loss per year, at present (1992-2011) rates, we get:

    = 140,845 years (!)

    More than 140 thousand years before Greenland’s and Antarctica’s (99% of all the world’s) glaciers and ice caps melt in their entirety.

    That’s more than ten times longer than the interglacial climatic period (known as the Holocene) that has prevailed since the end of the last ice age. Longer, indeed, than the entirety of the foregoing ice age itself, ever since the last preceding interglacial epoch.

    Even if the rate of melting does dramatically speed up over future decades, does it sound like all that ice is going to disappear anytime soon?

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