Climate: Are ice-free Arctic summers coming soon?

Posted on April 13, 2013 by Bob Berwyn

Study compares models to estimate a range of dates

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Scientists explore the melting ice of the Arctic. Photo courtesy NOAA.

By Summit Voice

FRISCO— No matter which you slice it, the Arctic Ocean is likely to almost free of summer ice by mid-century, and possibly within the next couple of decades. according to a new study by federal scientists.

By comparing three different predictive models, the researchers came up with a range of dates when most of the Arctic Ocean ice will melt away for at least a couple of months during the northern hemisphere summer.

The most aggressive models, which weigh recent trends more heavily, suggest ice-free conditions could come as soon as 2020. Under a second group of models that rely on weighing the future probability of “extreme” but random ice-melt events, the ice-free date is pushed back to 2030. The most conservative predictions are based on global climate models that use global climate models to forecast atmosphere, ocean, land, and sea ice conditions over time. (more…)

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Environment: Climate puzzle-pieces falling into place

Posted on April 7, 2013 by Bob Berwyn
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Dwindling Arctic ice, more intense rainstorms a sure bet, scientists say

By Bob Berwyn

FRISCO — While a handful of hardcore climate-science deniers are still trying to cast doubt on the legitimacy of what now amounts to decades of research, it’s pretty clear that some of long-term data trends are all pointing in the same direction.

Probably the best example is the research on Arctic sea ice. At this point, nobody can say exactly when the Arctic might be completely ice-free in the summer, but it’s pretty clear that the sea ice extent is on a steep downhill slide.

This past week, the National Climatic Data Center announced that this winter’s ice maximum was the fifth-lowest on record. Each month of the year shows a downward trend in sea ice extent, but the most remarkable fact in this week’s update was the finding that thin, first-year ice now dominates most of the Arctic Ocean, including the North Pole, and that older ice is dwindling even along the north coast of Greenland, previously a stronghold for thick ice. (more…)

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Climate: Thin, first-year ice now dominates Arctic Ocean

Posted on April 6, 2013 by Bob Berwyn
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The map at top shows the ages of ice in the Arctic at the end of March 2013; the bottom graph shows how the percentage of ice in each age group has changed from 1983 to 2013. Credit: NSIDC courtesy J. Maslanik and M. Tschudi, University of Colorado.

Seasonal shift begins in northern latitudes

By Summit Voice

FRISCO — It’s just the very start of the melt season in the Arctic, but sea ice has already dropped below last year’s level, which ended with a record low extent in September.

In the early April update, the National Snow and Ice Data Center reported that levels of multiyear ice remain extremely low. Satellite data suggests that first-year ice may now cover the North Pole area for the first time since the winter of 2008.

For March, the average extend was about 5.81 million square miles, which is about 274,000 square miles below the 1979 to 2000 average extent, and about 236,000 square miles above the record low for the month, set in 2006. March sea ice extent is declining at a rate of about 2.5 percent each decade, losing about 15,300 square miles per year, (about the size of Maryland and Delaware combined). (more…)

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Climate: This year’s maximum Arctic sea ice extent was the 6th-lowest on record

Posted on March 26, 2013 by Bob Berwyn
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Arctic sea ice has already dipped below the extent measured at this time last year, when the icecap ultimately dwindled to a record low.

Trend of dwindling ice continues unabated

By Summit Voice

FRISCO — Arctic sea ice extent peaked in mid-March and is now starting to shrink again, according to researchers with the National Snow and Ice Data center, who said that this year’s maximum extent was the sixth-lowest on record. At 5.84 million square miles, it was 283,000 square miles below the 1979 to 2000 average. (more…)

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Climate: Arctic sea ice stays below average in February

Posted on March 7, 2013 by Bob Berwyn

Downward trend continues …

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Antarctic sea ice was above normal in February and throughout the southern hemisphere summer, but that doesn’t balance the losses in Arctic sea ice, according to climate scientists. This NASA image shows ice in the Weddell Sea. Visit this NASA Earth Observatory web page for more information on Antarctic sea ice.

By Summit Voice

FRISCO — With the spring equinox approaching, Arctic sea ice is nearing its maximum seasonal extent for the year, and the National Snow and Ice Data Center is reporting that there is no sign of any significant rebound in ice extent from the record-low levels of the last couple of years.

The average February Arctic sea ice extent has been declining at rate of 2.9 percent per decade since 1979, resulting in an overall decline of more than 1.57 million square kilometers (606,000 square miles) from 1979 to 2013. Read the full NSIDC report here. (more…)

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Global warming: Geographers eye future Arctic shipping routes

Posted on March 5, 2013 by Bob Berwyn
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The fastest navigation routes for ships seeking to cross the Arctic Ocean by mid-century include the Northwest Passage (on the left) and over the North Pole (center), in addition to the Northern Sea Route (on the right).

New study looks at Arctic sea ice projections and also explores geopolitical issues

By Summit Voice

FRISCO — A new study helps quantify some of recent speculation about shipping routes through the Arctic, indicating that, in 40 years, normal seagoing vessels will be able to  navigate previously inaccessible parts of the Arctic Ocean without the help of icebreakers.

The Arctic ice sheet is expected to thin to the point that polar icebreakers will be able to navigate between the Pacific and Atlantic oceans by making a straight shot over the North Pole, according to UCLA geographers Laurence C. Smith and Scott R. Stephenson. (more…)

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Federal appeals court upholds polar bear protection

Posted on March 2, 2013 by Bob Berwyn
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Polar bears are threatened by global warming and qualify for protection under the Endangered Species Act. Photo courtesy Susanne Miller/USFWS.

Court rejects challenge by Alaska and trophy hunters

By Summit Voice

SUMMIT COUNTY — A federal appeals court has rebuffed Alaska’s efforts to weaken polar bear protection under the Endangered Species Act.

Explaining that global warming has already caused reductions in survival and recruitment rates in some regions, the D.C. Circuit Court of Appeals ruled that the U.S. Fish and Wildlife Service satisfied its duties under the law and adequately supported it decision to protect polar bears from extinction. Read the decision here.

The agency said the record makes it clear that federal biologists were aware of Alaska’s concerns and addressed them during the listing process. “We find … that under any reasonable reading of the Act, FWS committed no error in its response to the concerns raised by the State of Alaska,” the appeals court wrote in the March 1 ruling. (more…)

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New data confirms rapid loss of Arctic sea ice volume

Posted on February 14, 2013 by Bob Berwyn

Multiple measurements all show the same thing — Arctic ice is vanishing

Arctic sea ice is shrinking both in extent and volume, which is down by 30 percent in the past 10 years. Photo courtesy Bonnie Light, University of Washington.

Arctic sea ice is shrinking both in extent and volume, which is down by 30 percent in the past 10 years. Photo courtesy Bonnie Light, University of Washington.

By Summit Voice

FRISCO — Arctic sea ice extent was in the headlines last September, when researchers reported a new record low, and additional research shows that, not only is the coverage shrinking, it’s getting thinner — much thinner.

Combining data from a European Space Agency satellite with a University of Washington sea ice analysis suggests that the total volume has declined by 30 percent in just the past 10 years. Last summer’s minimum sea ice was just 20 percent of the total volume measured in 1980, when the satellite record starts.

The scientists are confident of their calculations because the model combines measurements from a variety of sources, including weather records, sea-surface temperature and satellite pictures of ice coverage to compute ice volume. It then verifies the results with actual thickness measurements from individual moorings or submarines that cruise below the ice (PIOMAS). (more…)

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Climate: Arctic ice melting from ‘the inside-out’

Posted on January 21, 2013 by Bob Berwyn

Tarns speed melting of ice cap

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Young sea ice is more susceptible to melting from within. Photo courtesy Stefan Hendricks, Alfred Wegener Institute.

FRISCO — German scientists say they’ve discovered another positive global warming feedback which could cause Arctic sea ice to melt faster than anticipated. During recent research expeditions in the Arctic they’re observed a large number of melt ponds on the surface, covering about half of the one-year ice.

“The ice cover of the Arctic Ocean has been undergoing fundamental change for some years. Thick, multi-year ice is virtually nowhere to be found any more,” said Marcel Nicolaus, of the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research.

“Instead, more than 50 percent of the ice cover now consists of thin one-year ice on which the melt water is particularly widespread. The decisive aspect here is the smoother surface of this young ice, permitting the melt water to spread over large areas and form a network of many individual melt ponds,” Nicolaus said.

By contrast, the older ice has a rougher surface which has been formed over the years by the constant motion of the floe and innumerable collisions. Far fewer and smaller ponds formed on this uneven surface which were, however, considerably deeper than the flat ponds on the younger ice.

As part of their research, sea ice physicists at the institute have now measured the light transmission through the Arctic sea ice for the first time on a large scale, enabling them to quantify consequences of this change. In areas where melt water collects on the ice, far more sunlight and therefore energy is able to penetrate the ice than is the case for white ice without ponds. That means the ice is absorbing more solar heat, is melting faster, and more light is available for the ecosystems in and below the ice. The findings have been published inGeophysical Research Letters.

“We knew that an ice floe with a thick and fresh layer of snow reflects between 85 and 90 per cent of sunlight and permits only little light through to the ocean. In contrast, we could assume that in summer, when the snow on the ice has melted and the sea ice is covered with melt ponds, considerably more light penetrates through the ice,” he said.

To find out the extent to which Arctic sea ice permits the penetration of the sun’s rays and how large the influence of the melt ponds is on this permeability, the researchers equipped a remotely operated underwater vehicle with radiation sensors and cameras. In the summer of 2011 during an Arctic expedition of the research ice breaker POLARSTERN, they sent this robot to several stations directly under the ice. During its underwater deployments, the device recorded how much solar energy penetrated the ice at a total of 6000 individual points all with different ice properties.

“The young thin ice with the many melt ponds does not just permit three times as much light to pass through than older ice. It also absorbs 50 per cent more solar radiation. This conversely means that this thin ice covered by melt ponds reflects considerably fewer sun rays than the thick ice. Its reflection rate is just 37 percent. The young ice also absorbs more solar energy, which causes more melt. The ice melts from inside out to a certain extent,” Nicolaus said.

“We assume that in future climate change will permit more sunlight to reach the Arctic Ocean … particularly that part of the ocean which is still covered by sea ice in summer … The greater the share of one-year ice in the sea ice cover, the more melt ponds will form and the larger they will be.

“This will also lead to a decreasing surface albedo and transmission into the ice and ocean will increase,” he said. “The sea ice will become more porous, more sunlight will penetrate the ice floes, and more heat will be absorbed by the ice. This is a development which will further accelerate the melting of the entire sea ice area.”

However, at the same time the organisms in and beneath the ice will have more light available to them in future. Whether and how they will cope with the new brightness is currently being investigated in cooperation with biologists.

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Global warming: Citing shrinking sea ice, feds list several Arctic seal species as threatened and endangered

Posted on December 24, 2012 by Bob Berwyn

Listing decision underscores climate-change threats to Arctic ecosystems

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Bearded seals are vulnerable to shrinking sea ice, declining snow cover. Photo courtesy NOAA.

By Summit Voice

FRISCO — Recognizing that the best available science suggests a significant loss of Arctic sea ice in the next few decades, federal biologists last week finalized Endangered Species Act protection for two species of ice-dependent seals.

NOAA will list as threatened the Beringia and Okhotsk populations of bearded seals, and the Arctic, Okhotsk, and Baltic subspecies of ringed seals. The Ladoga subspecies of ringed seals will be listed as endangered. The species that exist in U.S. waters (Arctic ringed seals and the Beringia population of bearded seals) are already protected under the Marine Mammal Protection Act.

“Our scientists undertook an extensive review of the best scientific and commercial data. They concluded that a significant decrease in sea ice is probable later this century and that these changes will likely cause these seal populations to decline,” said Jon Kurland, protected resources director for NOAA Fisheries’ Alaska region. “We look forward to working with the State of Alaska, our Alaska Native co-management partners, and the public as we work toward designating critical habitat for these seals.” (more…)

Filed under: Arctic, biodiversity, climate and weather, endangered species, Environment, global warming, Uncategorized | Tagged: , , , , , , , , | Leave a Comment »

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