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
Filed under: Arctic, climate and weather, global warming | Tagged: Arctic climate change, Arctic sea ice, climate change, Environment | Leave a comment »
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.
Filed under: Arctic, climate and weather, global warming | Tagged: Arctic sea ice, climate change, global warming, polar ice cap albedo | Leave a comment »
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
Filed under: Arctic, climate and weather, global warming | Tagged: Arctic sea ice, climate, global warming, sea ice extent | 2 Comments »
Posted on February 23, 2014 by Bob Berwyn
The magnitude of surface darkening is twice as large as that found in previous studies
By Summit Voice
FRISCO — The Arctic ice cap is more than just a home for polar bears. During the summer, the vast expanse of white helps cool the earth — like putting a wet, white bandana on your head during a hot summer summer day.
But as the sea ice extent shrinks each year, the cooling effect is diminished. And climate models may be underestimating the impacts of the loss of Arctic Sea ice, according to new research based on detailed satellite measurements of the Earth’s reflectivity.
As the sea ice melts, its white reflective surface is replaced by a relatively dark ocean surface. This diminishes the amount of sunlight being reflected back to space, causing Earth to absorb an increasing amount of solar energy. Continue reading
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Posted on February 19, 2014 by Bob Berwyn
Study links warming climate and Arctic cyclone frequency
A cyclonic storm spins over the center of the Arctic Ocean. Photo courtesy NASA/Goddard/MODIS Rapid Response Team. Visit this NASA website for more information.
By Summit Voice
FRISCO — A changing air pressure regime over the Arctic resulting from warmer temperatures may be driving an increase in extreme storms in the region. The hurricane-like cyclones that traverse the northern waters from Iceland to Alaska may foreshadow even more intense weather ahead, according to Dr. Stephen Vavrus, of the University of Wisconsin-Madison.
“This research shows that the Arctic appears to be expressing symptoms expected from ongoing climate change,” Vavrus said, explaining the findings of the study published in Geophysical Research Letters.
“The long-term decline in atmospheric pressure over most of the Arctic is consistent with the response typically simulated by climate models to greenhouse warming, and this study finds a general corresponding increase in the frequency of extreme Arctic cyclones since the middle 19th century,” he said. Continue reading
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Posted on January 24, 2014 by Bob Berwyn
A polar bear roams a coastal strand. Photo courtesy Susanne Miller, USFWS.
Studies show changing foraging behavior
By Summit Voice
FRISCO — A shared genetic heritage with brown bears may enable some polar bears to adapt as their icy Arctic hunting grounds shrink in the face of global warming.
As Arctic sea ice dwindles, polar bears have a limited amount of time to hunt their historically preferred prey — ringed seal pups — and must spend more time on land.
But polar bears in the western Hudson Bay region are using flexible foraging strategies while on land, such as prey-switching and eating a mixed diet of plants and animals, as they survive in their rapidly changing environment.
“There is little doubt that polar bears are very susceptible as global climate change continues to drastically alter the landscape of the northern polar regions,” said Robert Rockwell, a research associate at the American Museum of Natural History’s department of ornithology. “But we’re finding that they might be more resilient than is commonly thought.” Continue reading
Filed under: Arctic, biodiversity, climate and weather, endangered species, Environment, global warming | Tagged: Arctic sea ice, climate change, endangered species, global warming, polar bears | 2 Comments »
Posted on January 20, 2014 by Bob Berwyn
Ice extent shrinking about 18,000 square miles per year
What’s happening with polar sea ice?
By Summit Voice
FRISCO — December sea ice in the Arctic remained well below average, with the average extent ending up as the fourth-lowest on record — 270,300 square miles below the 1981 to 2010 average — according to the monthly update from the National Snow and Ice Data Center.
Low-ice conditions prevailed in the Barents Sea and along the entire northwest Pacific coast, including the Bering Sea and the Sea of Okhotsk. In the Greenland Sea and Baffin Bay, sea ice extent was near average.
The early part of December was dominated by a positive Arctic Oscillation pattern, but this shifted to near-neutral conditions by the end of the month. The Icelandic low, covering much of the northern North Atlantic Ocean, was stronger than average, and pressures were higher than average over the Bering Sea and Alaska. Continue reading
Filed under: climate and weather, global warming, Greenland | Tagged: Antarctical, Arctic sea ice, climate, global warming | 1 Comment »
Posted on October 29, 2013 by Bob Berwyn
Changes in the Arctic likely to have widespread hemispheric impacts
By Summit Voice
FRISCO — A new climate study by scientists at the University of Exeter (UK) adds to the growing body of research looking at the hemispheric impacts of dwinding Arctic sea ice.
The findings suggest that that the loss of ice shifts the jet stream farther south, bringing increased summer rainfall to northwestern Europe, but drier conditions to the Mediterranean region. The study could offer an explanation for the extraordinary run of wet summers experienced by Britain and northwest Europe between 2007 and 2012.
In another recent study, scientists with the Cooperative Institute for Research in Environmental Science found that as sea ice disappeared, the areas of relatively warm open water began to strongly influence the atmosphere, increasing surface temperatures in the region, and shifting low- and high-pressure zones around most markedly in the fall and winter.
And a NOAA study found Arctic warming has shifted the normal west-to-east flowing upper-level winds to a more north-south undulating, or wave-like pattern. This new wind pattern transports warmer air into the Arctic and pushes Arctic air farther south, and may influence the likelihood of persistent weather conditions in the mid-latitudes. Continue reading
Filed under: climate and weather, extreme weather, global warming | Tagged: Arctic sea ice, extreme weather, global warming impacts, Jet stream | 1 Comment »
Posted on September 21, 2013 by Bob Berwyn
At its minimum extent in mid-September, Arctic sea ice had left all coastlines — other than northern Greenland and parts of the Canadian Archipelago — free of ice. Map courtesy NSIDC.
Long-term trend still sharply downward
By Summit Voice
FRISCO — The Boulder-based National Snow and Ice Data Center is reporting that Arctic sea ice appears to have reached its minimum extent Sept. 13.
At about 1.97 million square miles, the minimum extent this year was not as extreme as last year’s record low, but still registered as the sixth-lowest on record.
The long-term trend is still a steady decline. Much of the Arctic may be completely free of of sea ice within the next few decades, said NSIDC director Mark Serreze.
“The pattern we’ve seen so far is an overall downward trend in summer ice extent, punctuated by ups and downs due to natural variability in weather patterns and ocean conditions,” Serreze said. Continue reading
Filed under: Arctic, climate and weather, global warming, Greenland | Tagged: Arctic sea ice, climate change, National Snow & Ice Data Center, NSIDC, Polar ice packs, sea ice minimum | Leave a comment »