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Global warming: Study shows Arctic sea ice melt season lengthening by five days per decade

Autumn freeze coming 11 days later in some regions

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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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Study: Arctic storm didn’t cause record-low sea ice

Super storm churned up sun-warmed water to speed melting

A new study suggests a massive Arctic storm last summer wasn't the main factor in record-low sea ice extent.

A new study suggests a massive Arctic storm last summer wasn’t the main factor in record-low sea ice extent. Photo courtesy NASA Earth Observatory.

By Summit Voice (Adapted from a University of Washington press release)

FRISCO — A huge Arctic cyclone last August was a factor in the record-low sea ice level last summer, but the ice would have melted to almost the same extent even without the storm, according to University of Washington scientists who studied the effects of the unusual storm over the high latitudes of the far north.

The study was published online this week in Geophysical Research Letters.

“The effect is huge in the immediate aftermath of the cyclone, but after about two weeks the effect gets smaller,” said lead author Jinlun Zhang, an oceanographer in the UW’s Applied Physics Laboratory. “By September, most of the ice that melted would have melted with or without the cyclone.” Continue reading

Climate: ‘On the verge of a new Arctic’

Credit: Dr. Kathy Crane, NOAA Arctic Research Office

A polar bear perches on an iceberg. Photo courtesy Dr. Kathy Crane, NOAA Arctic Research Office.

Top U.S. and Canadian scientists taking hard look at the implications of shrinking sea ice

By Summit Voice

SUMMIT COUNTY — Top U.S. and Canadian researchers are trying to develop a systematic way of studying the ongoing and impending changes in the Arctic. This week, the Navy’s chief of naval research, Rear Adm. Matthew Klunder, met with leaders from U.S. and Canadian government agencies to address research efforts in the Arctic, in response to dramatic and accelerating changes in summer sea ice coverage.

“We are surely on the verge of seeing a new Arctic,” said Arctic science expert Dr. Martin Jeffries. “And, since the Arctic is not isolated from the global environmental system … we can expect to see Arctic change have global environmental and socio-economic consequences.” Continue reading

Climate: Arctic sea ice peaks for the season

Thin ice formed in late season expected to melt quickly; thick, multi-year ice continues to decline

By Summit Voice

SUMMIT COUNTY — Arctic sea ice extent peaked in late March, reaching its highest level in the past 10 years, according to the National Snow and Ice Data Center’s monthly update.While sea ice extent in March was higher than in recent years, most of the ice that formed late in the season is very thin and expected to melt rapidly.

The average March sea ice extent of 5.87 million square miles is ranked ninth lowest out of the 34 years of satellite data for the month, but it was the highest March average ice extent since 2008 and one of the higher March extents in the past decade. Continue reading

Global warming: Harp seal habitat vanishing fast

Harp seal. PHOTO BY MATHIEU GODBOUT VIA WIKIPEDIA AND THE CREATIVE COMMONS.

Sea ice in breeding areas declining by 6 percent per decade; entire age classes are being lost

By Summit Voice

SUMMIT COUNTY — Along with declining habitat for polar bears, harp seal populations in the far north are also taking a big hit from global warming, according to researchers who documented reduced winter sea ice cover in key harp seal breeding grounds.

That decline has resulted in sharply higher death rates among seal pups in recent years, according to a new Duke University-led study. The researchers documented some movement of breeding harp seals to more stable sea ice environments, but thousands are still returning to traditional breeding grounds, where entire generations of seals are being lost.

“The kind of mortality we’re seeing in eastern Canada is dramatic. Entire year-classes may be disappearing from the population in low ice years – essentially all of the pups die,” said David W. Johnston, research scientist at the Duke University Marine Lab. “It calls into question the resilience of the population.” Continue reading

Global warming: Ancient driftwood offers sea ice clues

During the last 10.000 years the North Pole ice cover has been even smaller than it is today. PHOTO BY SVEN FUNDER, UNIVERSITY OF COPENHAGEN.

Tracing the age and origin of driftwood in northern Greenland enables scientists to estimate sea ice extent before accurate satellite measurements began

By Summit Voice

SUMMIT COUNTY — Tracking chunks of ancient driftwood as their main clues, a team of Danish researchers is unraveling some of the mysteries of the Arctic icepack.

The Polar region is the subject of intense day-to-day scrutiny by climate researchers, who are trying to understand what will happen to the sea ice as the Earth warms, and what the implications might be for ocean currents and global weather patterns.

One thing is clear — summer sea ice in the Arctic Ocean has been far from constant during the past 10,000 years. For big slice of that time, between 8,000 and 5,000 years ago, there was much less — by half — ice than now. The new study, to be published in the Journal Science, suggests that there was only half as much ice during that relatively warm period, known as the Holocene Climate Optimum.

The new study shows that, as ice disappears from one region, it may build up somewhere else, probably as a result of shifting wind patterns. That wind factor hasn’t been completely accounted for in most current studies on the loss of sea ice, the researchers said. Continue reading

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