Posted on April 16, 2014 by Bob Berwyn
Last year’s ozone hole over Antarctica was the second-smallest in 20 years, according to NASA.
CFC ban showing signs of success
FRISCO — Scientists say it’s unlikely that the Arctic will see ozone depletion on the scale of the Antarctic ozone hole, thanks mainly to international efforts to limit ozone-killing chemicals.
“While there is certainly some depletion of Arctic ozone, the extremes of Antarctica so far are very different from what we find in the Arctic, even in the coldest years,” said MIT atmospheric scientists Susan Solomon.
“It’s really a success story of science and policy, where the right things were done just in time to avoid broader environmental damage,” said Solomon, who made some of the first measurements in Antarctica that pointed toward CFCs as the primary cause of the ozone hole. Continue reading
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Posted on April 11, 2014 by Bob Berwyn
Study says iceberg conditions not unusually severe in 1912
FRISCO — The Titanic’s fateful encounter with a North Atlantic iceberg wasn’t a result of spring tides, and there weren’t an exceptionally high number of bergs in the North Atlantic in 1912, UK researchers said this week.
With the April 15 anniversary of the ocean liner’s sinking at hand, the University of Sheffield geographers say that, by scrutinizing historic iceberg data, they can dispel the theory that the Titanic was unlucky for sailing in a year with an exceptional number of icebergs. The risk of encountering a berg is actually much greater now, due to global warming. Continue reading
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Posted on April 8, 2014 by Bob Berwyn
Arctic sea ice extent is declining at 2.6 percent each decade.
March surge boosts extent late in the season
FRISCO — Arctic sea ice grew to its maximum extent for the year on March 21, reaching 5.70 million square miles. According to the National Snow and Ice Data Center, it was the fifth-lowest maximum extent in the satellite monitoring era, starting in 1978. The lowest maximum extent occurred in 2011, at 5.65 million square miles.
The average date for maximum sea ice extent is March 9, just a couple of weeks after the spring equinox, but the date varies from year to year. The latest maximum on record was in 2011, when sea ice extent expanded through March 31. Through 2014, the linear rate of decline for March ice extent is 2.6 percent per decade relative to the 1981 to 2010 average. Continue reading
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Posted on April 1, 2014 by Bob Berwyn
Melt pond on Arctic sea ice. Photo courtesy Polarstern.
Polar ice cap losing ground to global warming
FRISCO — While the Earth still sports an impressive mid-winter polar ice cap, more and more research suggests that global warming is eating away at the ice from the edges and from beneath, as warmer ocean temperatures delay the onset of sea ice formation.
On a geological scale, the pace is astounding. The length of the melt season for Arctic sea ice is growing by several days each decade, and an earlier start to the melt season is allowing the Arctic Ocean to absorb enough additional solar radiation. In some areas that heat is enough to melt as much as four feet of the Arctic ice cap’s thickness, according to a new study by National Snow and Ice Data Center and NASA researchers.
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Posted on March 23, 2014 by Bob Berwyn
Study says greening tundra won’t offset permafrost meltdown
Study says new plant growth won’t compensate for carbon emissions from melting tundra in the Arctic. bberwyn photo.
FRISCO — Permafrost could dwindle by 30 to 70 percent by the end of the century, and more vegetation in the Arctic won’t be enough to offset the carbon emissions from thawing organic soils.
Scientists with the Woods Hole Research Center reached their conclusions after a series of field tests designed to measure net gains or losses in carbon emissions. The study is published in the journal Ecology.
“Our results show that while permafrost degradation increased carbon uptake during the growing season, in line with decadal trends of ‘greening’ tundra, warming and permafrost thaw also enhanced winter respiration, which doubled annual carbon losses,” said WHRC assistant scientist Sue Natali. Continue reading
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Posted on March 11, 2014 by Bob Berwyn
A USGS study finds new permafrost forming near Alaska’s Twelvemile Lake.
Small local variations in temperatures eyed as factor
FRISCO — Scientists with the U.S. Geological Survey say they’ve found new patches of permafrost forming in the margins a retreating lake in the interior of Alaska. The findings run counter the conventional wisdom that permafrost will shrink and disappear as the Earth’s climate warms — but don’t jump on the happy train just yet.
The new permafrost patches are small and suggest that the areas of frozen soil are sensitive to small temperature variations and other local factors, the USGS-led study suggests. Especially important is emerging vegetation around the edge of the lake. Thick willows shade the ground to the point that the soil can freeze, the scientists said. Continue reading
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Posted on March 9, 2014 by Bob Berwyn
This year’s winter extent likely to be one of the lowest on record
Arctic sea ice extent this winter has been hovering near a record low. Graphic courtesy NSIDC.
By Summit Voice
FRISCO — With just a few more days to go before Arctic sea ice starts its annual retreat, it looks like this year’s maximum extent will be one the lowest on record. Sea ice extent has been tracking below average nearly all winter and dropped below previous record low levels in early February, staying there ever since.
The extent generally peaks in mid-March before it starts to give way to warmer air temperatures and longer days with more hours of sunlight. This year, temperatures in the Arctic have been distinctly higher than average, resulting in a slower than average expansion of the winter ice cover. Overall, sea ice grew at a rate about 26 percent slower than the 1981 to 2010 average. Continue reading
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Posted on March 5, 2014 by Bob Berwyn
Autumn freeze coming 11 days later in some regions
There’s probably no stopping the decline of Arctic sea ice.
By Summit Voice
FRISCO — Averaged across the Arctic, the melt season is lengthening by five days each decade, with much of the change coming in the fall, when a warmer ocean simply takes longer to freeze than in the past.
“The extent of sea ice in the Arctic has been declining for the last four decades,” said University College London researcher Julienne Stroeve, part of a research team that studied satellite data to track sea ice trends in the age of global warming.
The data confirm that the Arctic Ocean absorbing ever more of the sun’s energy in summer, leading to an ever later appearance of sea ice in the autumn. In some regions, autumn freeze-up is occurring up to 11 days per decade later than it used to. Continue reading
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Posted on February 28, 2014 by Bob Berwyn
Scientists see changes in the way marine mammals use the Bering Strait. Photo courtesy NASA.
Scientists say mitigation needed to protect marine life in the region
FRISCO — American and Russian scientists studying the Bering Strait say that global warming is changing the way marine mammals use the area. Species at home farther south are using the narrow passage to the Arctic Ocean much more often, the researchers said after monitoring the area for three years with underwater microphones.
The recordings show Arctic beluga and bowhead whales migrating seasonally through the region from the Arctic south to spend winter in the Bering Sea. They also detect large numbers of sub-Arctic humpback, fin and killer whales traveling north through the Bering Strait to feed in the biologically rich Chukchi Sea. Continue reading
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Posted on February 25, 2014 by Bob Berwyn
New tool to help coastal and ocean planners in the region
By Summit Voice
FRISCO — With Arctic sea ice at an all-time record low for late January and the melt season about to begin, researchers have created a new online tool that helps put ice conditions in historical perspective. Continue reading
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