Tag Archives: arctic ice

national geographic atlas

Striking new atlas shows dramatic extent of Arctic ice loss

national geographic atlas

Every five years for more than a century, National Geographic releases an atlas of the world complete with the latest geographic and geologic cartographic representations. The latest edition of Atlas of the World can be quite terrifying if you move up north, in the Arctic, for it shows just how dramatic ice loss has been in the past decades. For comparison, the GIF above stitches three edition (7th and 10th) from 2000 to 2015. The latest caption shows the Arctic as it had been in 2012, during its record low ice extent.

arctic sea ice lossSome have criticized National Geographic for its choice of representing the Arctic. The reason why the editor chose 2012, and not 2013 or 2014, was to remind people that the world is going through tough times and the effects of global warming are not as subtle as we might think. They’re very much real.

The sea ice extent of September 2012 was 56% lower than that in the same period of 2000, and 65% lower than 1975. The graph on the right shows how sea ice extent has evolved along the years.

As my colleague Andrei puts it:

“Throughout its geological history, the Earth’s climate has changed numerous times – there were times when there were no polar ice caps at all, and there were times when most of the Earth was frozen. But the key word here is “geological” – all these changes occurred over hundreds of thousands of years, if not millions. The climatic changes we are now witnessing are, according to the geological record, unprecedented in terms of speed; we are just now starting to understand the dramatic impact that this temperature shift is having.”

Ringed seals are the polar bear's primary food source--but a beached whale means a feast! © Daniel J. Cox/Natural Exposures

As Arctic ice goes, so do the polar bears. Study finds land food is inadequate to keep them fed

After carefully calculating the net nutritional gain polar bears have from land-based food like caribou, berries or bird eggs, researchers found this is far from enough to compensate their typical fat-rich diet based on marine mammals. In consequence, as ice retreats and spring hunting season shortens polar bear populations are expected to fall dramatically. According to the study, two-third of the world’s polar bears will disappear by mid-century and by the end of the century the could follow, if the issue is not addressed.

Ringed seals are the polar bear's primary food source--but a beached whale means a feast! © Daniel J. Cox/Natural Exposures

Ringed seals are the polar bear’s primary food source–but a beached whale means a feast! © Daniel J. Cox/Natural Exposures

Arctic sea ice has seen a sharp decline over the past four decades, as the sea ice cover is shrinking and thinning, making scientists think an ice-free Arctic Ocean during the summer might be reached this century. Ice grows dramatically each winter, usually reaching its maximum in March. It melts just as dramatically each summer, generally reaching its minimum in September. But since 1979 when satellite observations came into operation, this sea ice has been regularly thinning year in, year out. Since 2002, ice extent at the summer minimum has not returned to anything approaching the long-term average (1979-2000).

Despite sea ice has fluctuated, natural cycles alone like the Arctic Oscillation aren’t enough to explain the steep decline. Instead, most scientists argue that natural variability and greenhouse gas emissions (and the resulting rise in global temperatures) likely worked together to melt greater amounts of Arctic sea ice. The table below put together by NASA summarizes Arctic ice loss since 1979.

September/March (minimum/maximum) September Average Extent (millions of square kilometers) March Average Extent (millions of square kilometers)
1979–2000 mean 7.0 15.7
1999/2000 6.2 15.3
2000/2001 6.3 15.6
2001/2002 6.8 15.4
2002/2003 6.0 15.5
2003/2004 6.2 15.1
2004/2005 6.1 14.7
2005/2006 5.6 14.4
2006/2007 5.9 14.7
2007/2008 4.3 15.2
2008/2009 4.7 15.1
2009/2010 5.4 15.1
2010/2011 4.9 14.6
2011/2012 4.6 15.2
2012/2013 3.6 15.1
2013/2014 5.4 14.8

During summer, polar bears spend of their time on land. It’s in Winter than they get to munch on their favorite food (seals), but because the ice has been thinning the winter their land stints have been getting ever frequent. Because a handful of sightings have been reported of polar bears snacking on land-based food, some biologists argued that the polar bears would compensate this way for the seal meat. A team at  the US Geological Survey (USGS) found that this would be insufficient, however. The bears put in too much energy searching for berries or chasing down caribou, so the net nutritional gain is far from enough to keep them fed.

“Current evidence suggests it is unlikely terrestrial foods can make up for the calories polar bears lose out on in places where they are staying onshore longer than they have in the past,” said study author Karyn Rode, a wildlife biologist at the USGS. “In western Hudson Bay, during years when polar bears spend more time onshore and the ice-free period is longest, survival rates are lowest despite observed terrestrial feeding.”

“A really large bear has high energetic costs when they get up to forage, and these [terrestrial] resources are typically lower in calories or widely dispersed,” said Rode.

It’s not just that it’s not worth it for the bears to forage land food, there’s simply not enough to spare. On land, polar bears compete for food with Arctic Grizzlies, who also struggle to find food. The study, published in Frontiers in Ecology and the Environment, also notes that all the goose eggs in Canada’s Hudson Bay could maintain the 900 local polar bears for just a day and a half. This would mean a dramatic loss to the local ecosystem.

Arctic ice melting much faster than thought

Using both modern and historic measurements, researchers now have a more extensive view of how the Arctic sea ice has changed in the past few decades, finding that the ice is melting much faster than previously expected. The ice in the central Arctic Ocean thinned 65 percent between 1975 and 2012, from 11.7 feet (3.59 meters) to 4.1 feet (1.25 m).

On July 10, 2011, Don Perovich, of Cold Regions Research and Engineering Laboratory, maneuvered through melt ponds collecting optical data along the way to get a sense of the amount of sunlight reflected from sea ice and melt ponds in the Chukchi Sea.
Image credits: NASA.

“The ice is thinning dramatically,” said lead researcher Ron Lindsay, a climatologist at the University of Washington (UW) Applied Physics Laboratory. “We knew the ice was thinning, but we now have additional confirmation on how fast, and we can see that it’s not slowing down.”

Throughout its geological history, the Earth’s climate has changed numerous times – there were times when there were no polar ice caps at all, and there were times when most of the Earth was frozen. But the key word here is “geological” – all these changes occurred over hundreds of thousands of years, if not millions. The climatic changes we are now witnessing are, according to the geological record, unprecedented in terms of speed; we are just now starting to understand the dramatic impact that this temperature shift is having.

This particular study integrated all the studies documenting Arctic ice thickness; the data was acquired in a number of ways. For example, from 1975 to 1990, most ice-thickness readings were from under-ice submarines. These vessels once used sonar to measure ice drift so they could figure out where they could safely surface. The submarine data indicates that between 1975 and 2000 the ice thinned by 36 percent, which means that the rest of 29 percent thinned between 2000 and 2012.

“This confirms and extends that study,” Lindsay said. The larger data set used in the new study shows that the leveling off of sea ice thinning in the 1990s was only temporary, he said.

Since 2000, the satellite technology became viable enough to use it (along with airborne measurements) to estimate the ice’s thickness. While the ice’s extent is clearly visible from these measurements, thickness is more difficult to estimate, but it can be done. According to the study, direct, these measurements are just as accurate as hands-on ice-measuring methods used by people on the ground.

“Using all these different observations that have been collected over time, it pretty much verifies the trend that we have from the model for the past 13 years, though our estimate of thinning compared to previous decades may have been a little slow,” Schweiger said.

But not everyone is convinced; some researchers believe that there is not enough data to draw a definite conclusion and quantify the thinning of the Arctice ice. Julienne Stroeve, a sea ice researcher with the National Snow and Ice Data Center in Boulder, Colo., told Climate Central in an email:

“It would be great to have a long-term sea ice thickness dataset,” like the one Lindsay and Schweiger compiled, but there are inherent and varying biases in the data that make conclusions from such combined data hard to trust. Stroeve was not involved in the new study.

But even if the study overestimates (or maybe even underestimates) the rate at which the ice is thinning, it’s a step in the right direction – it’s an attempt to integrate different types of data, which is always challenging.

“This is just one attempt to put it together,” Lindsay said. “I think it is just a first step.”

The study was published in the journal The Criosphere. You can read the full article, for free HERE.

East Antarctica is sliding sideways

A song of ice and fire

Antarctica is split in two different areas: East Antarctica and West Antarctica – and East Antarctica wears the pants in this relationship: it’s pushing West Antarctica around – literally.

Since the Western part is losing weight due to melting and ice loss (billions of tons of ice per year), its softer mantle rock is being pushed more and more by the harder mantle beneath East Antarctica.

The discovery was made by researchers from The Ohio State University; they used highly sensitive GPS measurements to track any potential movement, and found that West Antarctic bedrock is being pushed sideways at rates up to about twelve millimeters per year (that’s about half an inch, for you non-metric people). This may not seem like much, but when you compare it to other areas around the world, it’s pretty huge.

The movement of the ice sheet is very important in understanding the effects of current ice loss, and also predict future loss. However, the team was quite surprised to see that the bedrock was in fact moving towards regions of greatest ice loss – the opposite you’d expect.

“From computer models, we knew that the bedrock should rebound as the weight of ice on top of it goes away,” Wilson said. “But the rock should spread out from the site where the ice used to be. Instead, we see movement toward places where there was the most ice loss.”

In order to understand this, they also analyzed the seismic information. They found that seismic waves pass faster through East Antarctica than through West Antarctica; since the bedrock is pretty much identical between the two, the difference must be caused by temperature. Rocks travel slower through hotter rocks, so this means that West Antarctica contains warmer, softer rock, and East Antarctica has colder, harder rock.

Stephanie Konfal, a research associate with POLENET, pointed out that where the transition is most pronounced, likening it to a jar of honey:

“If you imagine that you have warm spots and cold spots in the honey, so that some of it is soft and some is hard,” Konfal said, “and if you press down on the surface of the honey with a spoon, the honey will move away from the spoon, but the movement won’t be uniform. The hard spots will push into the soft spots. And when you take the spoon away, the soft honey won’t uniformly flow back up to fill the void, because the hard honey is still pushing on it.”

All this is caused by what’s happening in the mantle – the crust is just along for the ride.

Story Source:

The above story is based on materials provided by Ohio State University.

Record Arctic ice loss – or why Spring isn’t coming

It’s important to understand that our planet’s climate consists of so much interconnected elements, that what happens someplace affects virtually the entire Earth. Thing is, few people realize the huge impact the warming in the Arctic has on global climate.

arctic_ice-melting

At a news conference held on Tuesday, several researchers said that the melting ice may be weakening the jet stream currents, causing very cold weather to hang around more in the Northern latitude.

The jet stream is a massive current of air that blows from east to west, several miles above the Earth’s surface. It changes position over time, pushing massive weather systems around and preventing them from staying in any one place too long. However, as weather continues to warm more and more, ice continues to melt more and more; water of course doesn’t reflect as much solar energy as ice and snow, and as a result, it melts even more, and this heats the atmosphere above, which influences the atmospheric pressure.

This change in pressure in particular slows the jet stream, which means that it can’t can transport less warm air over land in the winter, causing snow and cold to stick with us a little longer. Unfortunately, it’s not going to get any better in future years unless conditions change – and in terms of Arctic ice loss, it doesn’t look very likely.

“The sea ice is going rapidly. It’s 80 percent less than it was just 30 years ago,” said Jennifer Francis, research professor with the Rutgers Institute of Coastal and Marine Science, in an interview with The Guardian. “This is a symptom of global warming and it contributes to enhanced warming in the Arctic.”

Considering recent trends, it’s more likely that conditions will worsen. With less ice, the area absorbs more heat. With more heat, more ice melts – and the cycle, once started, fuels itself.

Projected Arctic shipping routes.

Global warming will open shipping routes directly through the North Pole by 2050

A group of researchers assessed seven individual climate models and found that in each case common open water vessels will be able to navigate through portions of the Arctic, currently possible only with icebreaker ships, by the mid-century. Moreover, the thinning ice will allow ice-strengthened vessels to sail directly over the pole, something currently unimaginable, dramatically shortening travel distance, time and cost. The new shipping routes also means that governments need to revise their policies in order to tackle environmental, political and strategic threats.

Last year, a total of 46 ships made their way through the north of Russia via the “northern sea route” – considerably more than in the past due to a seven year streak of ever thinning Arctic ice. After assessing climate forecasts for the years 2040 to 2059, University of California researchers found that open water vessels should be able to travel along this route without the need of being escorted by icebreaker ships by 2050.

“We’re talking about a future in which open-water vessels will, at least during some years, be able to navigate unescorted through the Arctic, which at the moment is inconceivable,” says PhD candidate Scott Stephenson.

Projected Arctic shipping routes.

Projected Arctic shipping routes.

Moreover, the Arctic ice sheet is expect to thin and retreat to such an extent that polar icebreakers will be able to head from the Pacific to the Atlantic ocean by traveling straight across the North Pole. The best period for such an endeavor will be September, when historically annual sea ice cover in the Arctic Ocean is at its lowest extent.

Previously we’ve reported on a separate study that reached similar findings in its projections for the future, however this is the first to assert the sound possibility of an open shipping route through the North Pole itself.

“Nobody’s ever talked about shipping over the top of the North Pole,” says geography professor Laurence Smith. “This is an entirely unexpected possibility.”

With this in mind, in 2050 a shorter northern sea route is expected to save medium-sized bulk carrier 18 days and 580 tonnes of bunker fuel on a journey between northern Norway and China, translating in economic savings between $200,000 and $350,000 per trip. A journey straight through the North pole would mean 40% in savings, however.

New shipping routes mandate, however, new regulations which the world’s governments need now to consider. Russia, Canada and the United States will most likely engage in arguments over sea water sovereignty in the near future. Bitter picking between governments for economic benefits is of least interest to us however, what’s important is that strict laws regarding environmental protection that need to be put in place. The future’s Arctic routes are currently home to pristine environments that might become unbalanced as a result of busy and polluting ships.

“The prospect of common open water ships, which comprise the vast majority of the global fleet, entering the Arctic Ocean in late summer, and even its remote central basin by moderately ice-strengthened vessels heightens the urgency for a mandatory International Maritime Organisation regulatory framework to ensure adequate environmental protections, vessel safety standards, and search-and-rescue capability,” the report says.

The UCLA findings were reported in the journal PNAS.

A new model of flood waters from melting of the Laurentide Ice Sheet and large glacial lakes along its edge that covered much of North America from the Arctic south to New England over 13,000 years ago, shows the meltwater flowed northwest into the Arctic first. This weakened deep ocean circulation and led to Earth’s last major cold period.The direction of meltwater drainage is shown by the yellow arrows. The approximate position of the ice sheet is shown (in white) just before the onset of the Younger Dryas. The ocean colors are surface salinity from the control integration with warm (cold) surface currents shown in red (blue). (c) Alan Condron, UMass Amhers

Trigger for Earth’s last ‘big freeze’ located by geoscientists

Some 12,900 years ago, a massive flood of melted freshwater in the Arctic caused a 1,200-year-long chill nicknamed the “Big Freeze.” During this time much of the Northern Hemisphere was engulfed by centuries of cold, which caused the extinction of most great mammals, like mammoths, as well as the Clovis people. For decades, scientists have been debating from where and how did the freshwater flood flow. Now, a team of scientists may have finally reached a conclusion after they devised a computer model.

Technically known as the Younger Dryas, this specific period wasn’t a glacial period or what’s commonly referred to as an “ice age”, since it was a cold time in an otherwise warm span between ice ages. In other words, the Big Freeze wasn’t part of the Earth’s natural warm/cold cycle, it was triggered by an event. Previous theories held that a cosmic impact caused the Big Freeze, however recently scientist have reached to a common conclusion that a vast pulse of freshwater is to blame.

A new model of flood waters from melting of the Laurentide Ice Sheet and large glacial lakes along its edge that covered much of North America from the Arctic south to New England over 13,000 years ago, shows the meltwater flowed northwest into the Arctic first. This weakened deep ocean circulation and led to Earth’s last major cold period.The direction of meltwater drainage is shown by the yellow arrows. The approximate position of the ice sheet is shown (in white) just before the onset of the Younger Dryas. The ocean colors are surface salinity from the control integration with warm (cold) surface currents shown in red (blue). (c) Alan Condron, UMass Amhers

A new model of flood waters from melting of the Laurentide Ice Sheet and large glacial lakes along its edge that covered much of North America from the Arctic south to New England over 13,000 years ago, shows the meltwater flowed northwest into the Arctic first. This weakened deep ocean circulation and led to Earth’s last major cold period.The direction of meltwater drainage is shown by the yellow arrows. The approximate position of the ice sheet is shown (in white) just before the onset of the Younger Dryas. The ocean colors are surface salinity from the control integration with warm (cold) surface currents shown in red (blue). (c) Alan Condron, UMass Amhers

The source of this great flood was the massive glacial Lake Agassiz, located along the southern margin of the Laurentide Ice Sheet, which at its maximum 21,000 years ago was 6,500 to 9,800 feet (2,000 to 3,000 meters) thick and covered much of North America, from the Arctic Ocean south to Seattle and New York. Researchers believe the flood was caused by a sudden melting of an ice dam. The subsequent massive influx of freshwater diluted the circulation of saltwater in the North Atlantic, disrupting the ocean “conveyer belt” that transports heat to Europe and North America. The weakening of this circulation caused by the flood resulted in the dramatic cooling of North America and Europe.

Until recently, however, scientists weren’t sure whether the meltwater flowed northwest into the Arctic first, or east via the Gulf of St. Lawrence.

“This episode was the last time the Earth underwent a major cooling, so understanding exactly what caused it is very important for understanding how our modern-day climate might change in the future,” says Condron of UMass Amherst’s Climate System Research Center

Working with Peter Winsor at the University of Alaska, Condron used a high resolution, global, ocean-ice circulation model that is 10 to 20 times more powerful than previously attainable, to compare how different drainage outlets was delivered to the sinking regions in the North Atlantic. If Lake Aggasiz drained into the North Atlantic down the St. Lawrence River then the thermohaline circulation would have weakened by less than 15 percent. In contrast, when the meltwater first drains into the Arctic Ocean, narrow coastal boundary currents can efficiently deliver it to the deep water formation regions of the sub-polar north Atlantic, weakening the thermohaline circulation by more than 30 percent.

These findings hint that shifts in the flow of water in the Arctic could dramatically alter today’s climate.

“However, in our modern-day climate, there are no sources of freshwater as large as the glacial lakes or Laurentide Ice Sheet readily available to suddenly flood into the ocean,” Condron said. “As a result, we should be cautious using this study as an analog for what might trigger modern-day abrupt climate change.”

The researchers are able, however, to put their model to good use in other instances, though far less extreme, like studying the effects of the potential melting of large ice sheet over Greenland and changes in the hydrological cycle, such as increased river runoff of the Arctic in the near-future.

Findings were published in the journal Proceedings of the National Academy of Sciences.

Source: University of Massachusetts at Amherst

Arctic ice hits new low, expected to collapse of sea ice within four years

Arctic ice, a key indicator for global climate status, has reached another record low, lower than in computer estimates, hinting at a major disaster.

A new record

Researchers from the U.S. National Snow and Ice Data Center announced reached its lowest point on September 16, when it will cover approximately 1.32 million square miles (3.42 million square km) of the Arctic Ocean – the least since satellite records began 33 years ago. However, it might go even lower in days to come, depending on changing weather conditions. A final analysis is expected next month.

“We are now in uncharted territory,” Mark Serreze, the center’s director, said in a statement. “While we’ve long known that as the planet warms up, changes would be seen first and be most pronounced in the Arctic, few of us were prepared for how rapidly the changes would actually occur.”

Arctic ice isn’t just retreating, it’s also growing thinner, and this raises up new threats for the entire planet.

“What happens in the Arctic doesn’t stay in the Arctic,” said Dan Lashof, a climate scientist at the nonprofit Natural Resources Defense Council. “This has a real impact on Americans where they live and work.”

Global warming – beyond our control?

The situation truly seems dire; one of the leading authorities in the world, Prof Peter Wadhams of Cambridge University calls for urgent measures, predicting the collapse of the Arctic sea ice in summer months within four years. The amplitude of this disaster would bring consequences more dire than even the pessimists would have expected.

“At first this didn’t [get] noticed; the summer ice limits slowly shrank back, at a rate which suggested that the ice would last another 50 years or so. But in the end the summer melt overtook the winter growth such that the entire ice sheet melts or breaks up during the summer months. This collapse, I predicted would occur in 2015-16 at which time the summer Arctic (August to September) would become ice-free. The final collapse towards that state is now happening and will probably be complete by those dates”, he details.

“That is a truly staggering rate of melting, far beyond what scientists thought would happen a few years ago,” Bob Ward of the London School of Economics and Political Science said in a statement. “Policy-makers need to wake up to the scale and pace of the impacts from climate change.”

Recent climate models suggest the Arctic could be ice-free by 2050, but usually, these climate models tend to be optimistic, often unable to comprise the full extent of the damage. Wadhams says the implications are “terrible”.

“The positives are increased possibility of Arctic transport, increased access to Arctic offshore oil and gas resources. The main negative is an acceleration of global warming. As the sea ice retreats in summer the ocean warms up (to 7C in 2011) and this warms the seabed too. The continental shelves of the Arctic are composed of offshore permafrost, frozen sediment left over from the last ice age. As the water warms the permafrost melts and releases huge quantities of trapped methane, a very powerful greenhouse gas so this will give a big boost to global warming.”

Satellite photo of the Petermann glacier before the giant iceberg broke off the ice sheet. Notice a significant crack shaped like a circle arc. (c) NASA

Iceberg twice the size of Manhattan breaks off Greenland glacier

Researchers at the University of Delaware and the Canadian Ice Service recently reported that an ice island, whose surface is twice that of Manhattan, broke off from Greenland’s Petermann Glacier, one of the two largest glaciers left in Greenland connecting the great Greenland ice sheet with the ocean via a floating ice shelf.

The 46-square-mile giant iceberg broke off from the glacier on Monday, and has since started its journey towards the open ocean.The on-site discovery was confirmed with satellite imaging from the Moderate Resolution Imaging Spectroradiometer aboard NASA’s Terra and Aqua satellites.

Satellite photo of the Petermann glacier before the giant iceberg broke off the ice sheet. Notice a significant crack shaped like a circle arc. (c) NASA

Satellite photo of the Petermann glacier before the giant iceberg broke off the ice sheet. Notice a significant crack shaped like a circle arc. (c) NASA

An hour and a half after the previous image was taken, this photo shows the iceberg has begun to move toward the open ocean. (c) NASA

An hour and a half after the previous image was taken, this photo shows the iceberg has begun to move toward the open ocean. (c) NASA

Although the new iceberg is admitedly large, it rather pales in comparison to its predecessor from 2010, when a chuck of ice 97-square-mile chunk of ice broke off from the Petermann Glacier – the largest iceberg recorded in the Arctic since 1962. Last year, on the other side of the world, an iceberg the size of New York City broke off from the Antarctic ice sheet – 340-square-miles in surface.

Greenland ice sheet is melting and shrinking

“While the size is not as spectacular as it was in 2010, the fact that it follows so closely to the 2010 event brings the glacier’s terminus to a location where it has not been for at least 150 years,” says Andreas Muenchow, associate professor of physical ocean science and engineering in UD’s College of Earth, Ocean, and Environment.

“The Greenland ice sheet as a whole is shrinking, melting and reducing in size as the result of globally changing air and ocean temperatures and associated changes in circulation patterns in both the ocean and atmosphere,” he notes.

Muenchow points out that the air around northern Greenland and Ellesmere Island has warmed by about 0.11 +/- 0.025 degrees Celsius per year since 1987. This means Northern Greenland and Canada have been warming five times faster than the average global temperature, according to the scientist.

“Northwest Greenland and northeast Canada are warming more than five times faster than the rest of the world,” Muenchow says, “but the observed warming is not proof that the diminishing ice shelf is caused by this, because air temperatures have little effect on this glacier; ocean temperatures do, and our ocean temperature time series are only five to eight years long — too short to establish a robust warming signal.”

This is not an isolated incident. Many of glaciers in southern Greenland have been melting at an unusual rapid pace. If it continues, and more of the Petermann is lost, the melting would push up sea levels – the ice lost so far was already floating, so the breaks don’t add to global sea levels.

The new iceberg is expected to follow in the footsteps of the previous 2010 giant glacier, breaking apart into smaller icebergs as it moves away north, then west, before reaching the shores of Newfoundland.

Source: University of Delaware via Our Amazing Planet

A: The estuaries of the Ob' and Yenisei Rivers. B: The Lena River delta.

Alarmingly high mercury concentrations in the Arctic might be due to Siberian rivers

Besides ever thinning ice, permafrost melting, soot deposits, habitat loss, you might as well add another significant factor threatening the arctic ecosystem – mercury. For some time, the alarmingly high mercury concentrations in the regions were rather unaccounted for, in part, however a new research by scientists at Harvard’s Atmospheric Chemistry Modeling Group suggests that three Siberian rivers might be to blame.

The Lena, the Ob, and the Yenisei all flow north of Siberia and flush in the Arctic Ocean every spring after the ice formed through the winter melts. Environmental experts have assumed that the mercury gets up to high latitudes through the atmosphere, but a more in depth look showed that this explanation doesn’t stand.  Mercury levels tend to peak in the Arctic atmosphere in summer, but power-plant emissions are also highest in summer, when air conditioning sends the demand for electricity soaring. “It didn’t make sense,” said the study’s lead author, Jenny Fisher, a postdoctoral fellow with Harvard’s Atmospheric Chemistry Modeling Group in an interview. Mercury takes time for it to make its way north.

A: The estuaries of the Ob' and Yenisei Rivers. B: The Lena River delta.

A: The estuaries of the Ob' and Yenisei Rivers. B: The Lena River delta.

Mercury is a highly toxic substance, which severely affects the local ecosystem through food-chain poisoning. The substance doesn’t break down, and gets transferred as bigger animals eat smaller animals, from plankton, to seal, to polar bears, to the local Inuit population.

“The only thing that had the right signature is rivers,” Fisher said. Ice melting in the spring perfectly coincide with the mercury spikes in the Arctic. With ice cover melting back in the ocean as well, the mercury is free to enter the atmosphere, boosting concentrations far higher than they’d otherwise be. In fact, twice as much mercury comes from Siberian rivers as comes from northward-drifting air, the researchers found.

Possible source for the mercury outbreaks in the Siberian rivers might be local Russian mining operations, naturally occurring mercury leaching of the soil where it’s been frozen in place for tens of thousands of years due to permafrost melting, and even an alteration of the hydrologic cycle due to global warming.

It’s still just a hypothesis, Fisher said. “We really have limited knowledge of what’s really going on, and we’re hoping this work inspires more research. But it may be,” she said, “that climate change affects the Arctic in more ways than we thought.”

source: Climate Central

A man clearing the snow in front of the Lincoln Memorial, in Washington, DC, after a snow blizzard. (c) Reuters

Harsh winters linked to Arctic ice melting

A recent study performed by a team of American/Chinese scientists shows that there’s a direct link between the progressive shrinking ice in the Arctic and in the increasingly harsher snowy winters in the  US, Europe and China.

In the year 2007, the  level of Arctic sea ice hit a record low, which hasn’t recovered to this day. Since then, there’s been much more winter snow cover in large parts of the northern US, northwestern and central Europe and northern and central China, sparking researchers’ interest in the matter.

Of course, there have been a number of study previously released which discuss the impact increasing temperatures in the Arctic area, sparked by global warming, has on the weather. However, the present study goes a bit further, where others haven’t, and assess the strength of the cause-effect link.

“Our study demonstrates that the decrease in Arctic sea ice area is linked to changes in the winter Northern Hemisphere atmospheric circulation,” says Judith Curry, chair of the School of Earth and Atmospheric Sciences at Georgia Tech.

“The circulation changes result in more frequent episodes of atmospheric blocking patterns, which lead to increased cold surges and snow over large parts of the northern continents.”

The team of researches, headed by Jiping Liu from Georgia Institute of Technology in Atlanta, US, and the Insitute of Atmospheric Physics in Beijing, crunched numbers from data collected between 1979 and 2010, and observed a decrease in autumn Arctic sea ice of one million square kilometers corresponded to the greater increase in winter snow cover. A computer model was then put in place, which helped scientists discover two major factors that directly influenced the snowy winters of the past few years – a reduction of the northern jet stream strength, spurred by reduced air temperature difference between the Arctic and latitudes further south, over the Atlantic Ocean, and extra-atmospheric water vapor content, which makes the air more humid.

We think the recent snowy winters could be caused by the retreating Arctic ice altering atmospheric circulation patterns by weakening westerly winds, increasing the amplitude of the jet stream and increasing the amount of moisture in the atmosphere,” says senior research scientist Jiping Liu.

“These pattern changes enhance blocking patterns that favor more frequent movement of cold air masses to middle and lower latitudes, leading to increased heavy snowfall in Europe and the Northeast and Midwest regions of the United States.”

Computer simulations predict that within a certain time frame the Arctic might become completely ice-free in the summer and autumn – any time between 2016 and 2060. The researchers aren’t prepared, however, to claim whether the upcoming winters will get colder and snowier.

“It’s possible that future winters will be colder and snowier, but there are some uncertainties,” cautioned Dr Liu.

The researchers involved in the study, recently published in the journal Proceedings of the National Academy of Sciences (PNAS), stated that the next step in their work is to build various computer models of climate, and see whether they do forecast a growing winter chill.

 

Undated handout photo shows NASA scientists collecting data from thawing Arctic ice during the U.S. agency's ICESCAPE mission in July. (c) Kathryn Hansen, NASA

Arctic sea ice volume at record low in 2010

Undated handout photo shows NASA scientists collecting data from thawing Arctic ice during the U.S. agency's ICESCAPE mission in July. (c) Kathryn Hansen, NASA

Undated handout photo shows NASA scientists collecting data from thawing Arctic ice during the U.S. agency's ICESCAPE mission in July. (c) Kathryn Hansen, NASA

The arctic ice volume recorded last fall was the lowest ever since the first satellite reports were introduced, according to data furnished  by a new study which used complicated weather modeling, ocean observations, submarine data, and space-age monitoring.

“Sea ice volume is an important climate indicator,” said the team of scientists from  Polar Science Center of the University of Washington, who further explains here. “It depends on both ice thickness and extent and therefore more directly tied to climate forcing than extent alone. However, Arctic sea ice volume cannot currently be observed continuously.  Observations from satellites, Navy submarines, moorings, and field measurements are all limited in space and time.”

The melt season for Arctic sea ice climaxes each September or October, and many people closely track the satellite generated reports and analysis of sea ice extent by the National Snow and Ice Data Center. This year’s ice volume quite probably will be even thinner than the one reported last year, the current record holder for all time lows, since current data indicates arctic ice volumes plummeting a more rapid pace than last year.

Interestingly enough, as of July 31, this year, the last time numbers were crunched and posted online, the volume of sea ice appeared to be about 2,135 cubic miles — more than 50 percent lower than the average volume and 62 percent lower than the maximum volume of ice that covered the Arctic back in 1979, researchers said here. Those are very frightening figures, one which could lead to massive sea level rise  and weather disruption in the near future.

Called “Uncertainty in Modeled Arctic Sea Ice Volume”, the highly technical discussion recently published in the Journal of Geophysical Research tackles the current arctic melting crisis and offers insight on how scientists calculate, monitor and reality check the ongoing volume of sea ice in the Arctic Ocean using their Pan-arctic Ice Ocean Modeling and Assimilation System.