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Climate study shows nuances in Arctic carbon cycle

Warmer seas don’t always take up more carbon

West Antarctic ice sheets

How will melting sea ice affect global carbon cycles? bberwyn photo.

By Summit Voice

FRISCO — As sea ice inexorably declines, the Arctic Ocean has started to absorb more carbon — by some as estimates, as much as one additional megaton each each, thanks to increased biological productivity.

But those effects are not spread evenly across the region, according to a new study that paints a nuanced picture of how global warming is changing the carbon cycle in the Arctic. The MIT research team modeled changes in Arctic sea ice, temperatures, currents, and flow of carbon from 1996 to 2007, and found that the amount of carbon taken up by the Arctic increased by 1 megaton each year.

But their detailed analysis found that some areas of the Arctic where temperatures have warmed the most are actually storing less carbon. Instead, these regions — including the Barents Sea, near Greenland — have become a carbon source, emitting carbon dioxide to the atmosphere. Continue reading

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Study finds rapid warming in depths of Greenland Sea

greenland sea

Deep waters in the Greenland Sea are warming.

Abysmal sea temps in region rising 10 times faster than global average

By Summit Voice

FRISCO — Changing ocean dynamics have resulted in a distinct warming of deep waters in the Greenland Sea.

Since the 1980s, the water temperature between 2000 meters depth and the sea floor has risen by 0.3 degrees Celsius — enough heat energy to raise surface temperatures over Europe significantly. The rate of warming is about 10 times higher than the global average.

“This sounds like a small number, but we need to see this in relation to the large mass of water that has been warmed,” said Dr. Raquel Somavilla Cabrillo, who led the study for the Alfred Wegener Institute for Polar and Marine Research.

“‘The amount of heat accumulated within the lowest 1.5 kilometres in the abyssal Greenland Sea would warm the atmosphere above Europe by 4 degrees centigrade. The Greenland Sea is just a small part of the global ocean. However, the observed increase of 0.3 degrees in the deep Greenland Sea is ten times higher than the temperature increase in the global ocean on average,” Somavilla said. Continue reading

Climate: What if Arctic sea ice doesn’t form in winter?

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Arctic sea ice is on a downward spiral. Visit this NASA Earth Observatory website for information on this image.

New models look at year-round ice-free conditions to find parallels with Pliocene epoch

By Summit Voice

FRISCO — As atmospheric concentrations of carbon dioxide start to hover around 400 parts per million, climate scientists have been looking back about 3 to 5 million years, to the Pliocene Epoch — the last time heat-trapping greenhouse gases were at a similar level.

But temperatures during the Pliocene were about 3.5 to 9 degrees Fahrenheit warmer than today and the sea level was 65 to 80 feet higher. Until now, scientists have assumed that there’s a time lag between atmospheric CO2 levels and the subsequent temperature increases that melt ice and drive ocean levels up. Continue reading

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

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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). Continue reading

Report finds serious flaws with Shell’s Arctic drilling program

Equipment failures, environmental violations and lack of oversight need to be addressed before moving ahead with drilling plans

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Feds tell Shell to rethink Arctic offshore drilling plans.

* More coverage of Shell’s Arctic drilling program

By Summit Voice

FRISCO — Eager to exploit the Arctic for fossil fuel resources and to live up to shareholder expectations, Royal Dutch Shell rushed into its offshore drilling program without being “fully prepared in terms of fabricating and testing certain critical systems and establishing the scope of its operational plans,” according to a U.S. Department of Interior report released this week.

Key failures included Shell’s inability to get certification for an oil spill containment system  required to be on site in the event of a loss of well control. The report said the company’s failure to deploy the system was due “to shortcomings in Shell’s management and oversight of key contractors.”

The review was launched after a string of well-publicized problems culminated with a runaway drill rig that ended up running aground on a remote Alaskan island. The company is also under investigation for a string of violations of various environmental requirements. In February, Shell announced a one year pause in its Arctic drilling program to address the shortcomings. Continue reading

Arctic sea ice near record low in January

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January sea ice extent has been dropping about 3 percent per decade, according to the NSIDC.

Northern hemisphere snow cover above average in December and January

By Summit Voice

FRISCO — Arctic sea ice remained well below average during January, about 400,000 miles below the 1979 to 2000 average for the month and the sixth-lowest during the satellite record. The last ten years (2004 to 2013) have seen the ten lowest January extents in the satellite record.

According to the latest update from the National Snow and Ice Data Center, January sea ice extent has been decreasing at abou 3.2 percent per decade. The largest areas of open water were around the Barents Sea and near Svalbard, northeast of Greenland. Sea ice extent was also below average along the east coast of Greenland. Continue reading

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

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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