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Posts Tagged ‘Arctic’

What is the Arctic Ice ‘Death Spiral’?

August 14, 2013 1 comment

tcktcktck.org

Sea Ice Spiral

Arctic sea ice in the summer. Creative Commons: Guido Appenzeller, 2011

“The record or near-records being reported from year to year in the Arctic are no longer anomalies or exceptions. Really they have become the rule for us, or the norm that we see in the Arctic and that we expect to see for the forseeable future” – Jackie Richter-Menge, US Army Corps of Engineers

Last week’s ‘State of the Climate’ report confirmed it: ice is melting in the Arctic at one of the fastest rates in human history. Researchers and climate scientists monitoring ice melt in the Arctic have started using the ominous term ‘death spiral’ to describe what’s happening at the top of the world. But what does it mean? And is Read more…

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NOAA: 2012 shows climate change with record sea-level rise, Arctic melting, heated-up oceans

August 7, 2013 Comments off
washingtonpost.com

2012 arctic ice meltWASHINGTON — A new massive federal study says the world in 2012 sweltered with continued signs of climate change. Rising sea levels, snow melt, heat buildup in the oceans, and melting Arctic sea ice and Greenland ice sheets, all broke or nearly broke records, but temperatures only sneaked into the top 10.

The National Oceanic and Atmospheric Administration on Tuesday issued a peer-reviewed 260-page report, which agency chief Kathryn Sullivan calls its annual “checking on the pulse of the planet.” The report, written by 384 scientists around the world, compiles data already released, but it puts them in context of what’s been happening to Earth over decades.

“It’s critically important to compile a big picture,” National Climatic Data Center director Tom Karl says. “The signs that we see are of a warming world.”

Sullivan says what is noticeable “are remarkable changes in key climate indicators,” mentioning dramatic spikes in ocean heat content, a record melt of Arctic sea ice in the summer, and Read more…

Arctic Soil Releases Dangerous Levels of CO2, Speeding Global Warming

February 12, 2013 Comments off

scienceworldreport.com

Arctic

(Photo : Reuters) Global warming has caused scientists to worry as permafrost melts, releasing a vast amount of CO2 into the atmosphere and further perpetuating the problem.

For most of the year, the Arctic is frozen: its hard-packed tundra and ice forming solid ground. In fact, some of that ice never melts in what is known as permafrost, which stays solid all year. Now, global warming has caused scientists to worry as permafrost melts, releasing a vast amount of CO2 into the atmosphere and further perpetuating the problem.

Flooding triggered by melting snow washes vast amounts of carbon-rich soil from the land into the water. These waters contain most of the carbon that is currently being released from melting permafrost. Permafrost itself contains years of collected organic matter and when it collapses, it exposes new layers of soil to sunlight. Once this carbon is exposed, it is then oxidized by bacteria and produces CO2. In fact, scientists estimate that carbon from Read more…

Arctic sea ice extent continues to melt below former record lows: data center

September 6, 2012 Comments off

nunatsiaqonline

Every year there's less of the multi-year, blue-tinged sea ice, like this ice seen in the Northwest Passage, in the Arctic. (PHOTO BY JANE GEORGE)
Every year there’s less of the multi-year, blue-tinged sea ice, like this ice seen in the Northwest Passage, in the Arctic. (PHOTO BY JANE GEORGE)
Arctic sea ice extent for August 2012 was 4.72 million sq. km.The magenta line shows the 1979 to 2000 median extent for that month. The black cross indicates the geographic North Pole. (IMAGE COURTESY OF THE NSIDC)

Following the new record low Arctic sea ice extent recorded Aug. 26, ice coverage has continued to drop and has now shrunk to less than four million square kilometres — smaller than the previous low extent of 2007.

Compared to September conditions in the 1980s and 1990s, the Arctic sea ice extent has dropped by 45 per cent, the Colorado-based National Snow and Ice Data Center said Sept. 5.

And that skimpy sea ice cover is likely to get lower yet, because Read more…

Arctic methane leaks threaten climate

April 24, 2012 1 comment

newscientist.com

Methane released as ice retreats could force greater climate warming <i>(Image: KPA/Zuma/Rex Features)</i>Methane released as ice retreats could force greater climate warming (Image: KPA/Zuma/Rex Features)

As Arctic sea ice breaks apart, massive amounts of methane could be released into the atmosphere from the cold waters beneath.

High concentrations of the greenhouse gas have been recorded in the air above cracks in the ice. This could be evidence of yet another positive feedback on the warming climate – leading to even faster Arctic warming.

The Arctic is home to vast stores of methane – there are billions of tonnes of methane in permafrost alone. It is a potent greenhouse gas, so a major methane release would greatly accelerate climate change. The gas is found in icy crystals called hydrates beneath the shallow seas that flood some areas of the continental crust, as well as in permafrost. It is also being released from Arctic wetlands.

But this doesn’t explain why Eric Kort of the Jet Propulsion Laboratory in Pasadena, California, and his colleagues found patches of methane in remote regions of the Arctic Ocean, far from any of these known methane sources.

The team found the patches during five flights over the Arctic Ocean between 2009 and 2010, as part of a project to systematically map greenhouse gas levels in the atmosphere.

Kort estimates Read more…

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Greenland ice sheet may melt completely with 1.6 degrees global warming

March 12, 2012 Comments off

esciencenews

Greenland ice sheetPhoto: christine zenino/Flickr

The Greenland ice sheet is likely to be more vulnerable to global warming than previously thought. The temperature threshold for melting the ice sheet completely is in the range of 0.8 to 3.2 degrees Celsius of global warming, with a best estimate of 1.6 degrees above pre-industrial levels, shows a new study by scientists from the Potsdam Institute for Climate Impact Research (PIK) and the Universidad Complutense de Madrid. Today, already 0.8 degrees of global warming has been observed. Substantial melting of land ice could contribute to long-term sea-level rise of several meters and therefore it potentially affects the lives of many millions of people. The time it takes before Read more…

Oldest and thickest Arctic sea ice is disappearing

March 1, 2012 1 comment

earth-issues.com

Oldest Arctic Sea Ice is Disappearing

acquired November 1, 2011 – January 31, 2012download large image (1 MB, JPEG, 3840×2160)

A new study by NASA scientist Joey Comiso has found that the oldest and thickest Arctic sea ice is disappearing at a faster rate than the younger and thinner ice at the edges of the ice cap. The rapid disappearance of older ice makes the Arctic Ocean’s sea ice cap more vulnerable to further decline.

Arctic multi-year ice “extent”—which includes all areas where at least 15 percent of the ocean surface is covered by multi-year ice—has been vanishing at a rate of –15.1 percent per decade, Comiso found. Over the same period, the “area” covered by multi-year ice—which discards open water among ice floes and focuses exclusively on regions that are completely covered—has been shrinking by –17.2 percent per decade. The findings were Read more…