The Sea Ice Arctic Communities Rely on Could Disappear Three Weeks Earlier

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Let’s not walk on this ice, yeah? Here we see shorefast ice beginning to break up near Uummannaq, Greenland.
Let’s not walk on this ice, yeah? Here we see shorefast ice beginning to break up near Uummannaq, Greenland.
Photo: Sarah Cooley (Brown University)

Sea ice near the shore is crucial for dogsled travel for Arctic communities. But a new study shows that when temperatures crank up, it disappears faster—and it’s set to grow a lot worse by the end of the century.

Published in Nature Climate Change on Monday, the paper uses satellite imagery from 2000 to 2018 over 28 communities in northern Canada and western Greenland to track changes in so-called shorefast sea ice during the spring. That ice is a key connector for these remote, largely indigenous communities. During the winter and spring, it acts as a bridge to bring communities together and allows them to continue historic cultural practices that are essential to their way of life, such as seal hunting and dogsledding. But as the Arctic warms, it’s likely to breakup earlier and put those activities in jeopardy.

“Broadly speaking, the Arctic region faces some of the most dramatic impacts of climate change, and it is important to understand not only how these changes may feedback into global climate but also how they may affect local Arctic communities,” author Sarah Cooley, a PhD candidate at Brown University, told Earther in an email. “This result highlights the fact that climate change will not affect all places equally even within the Arctic and emphasizes the importance of taking localized, community-relevant approaches to studying climate change.”

The researchers looked at surface air temperatures to assess whether there was a connection and found that ice breakup is associated with spikes in temperature in 25 of the 28 communities they looked at. Though there’s no clear temperature trend over the relatively short satellite record they used for the study, the observing the correlation between shorefast ice loss and temperature allowed them to model what the future would look like under different climate scenarios.

They used three climate scenarios ranging from one where we draw down emissions rapidly to one where they rise. In all of the scenarios, there is a loss in the number of days the regions see this ice cover. Unchecked climate change would lead ice to break up 20 days earlier on average by century’s end while cutting emissions rapidly would only lead shorefast ice breakups happening an average of 7 days earlier. The findings also show that the colder it is, the more ice it’s projected to lose come spring. Regardless, the future of ice and the communities that depend on it will depend on how quickly leaders take action to avoid the worst.

The study only looked at temperature and ice. The team expects, however, that other weather patterns such as wind and waves also impact ice’s breakup date. There’s growing evidence that the Arctic could see more intense storms so the study may well be an underestimate of what the future holds for shorefast ice.

The Arctic has been transforming much sooner than scientists had expected. For Inuit communities, the climate crisis is already erasing critical pieces of their lives and history. Taking a closer look at ice thickness and ice stability will give scientists an even-fuller picture of the consequences of loss.

Arctic will see ice-free summers by 2050 as globe warms, study says

Doyle Rice

USA TODAY
  • Sea ice is frozen ocean water that melts each summer, then refreezes each winter.
  • Sea ice affects Arctic communities and wildlife such as polar bears and walruses.
  • As the climate changes, the Arctic is warming more than twice as fast as the rest of the planet.

The Arctic Ocean will be ice-free in the summer within the next 30 years, a study says, which will result in “devastating consequences for the Arctic ecosystem,” according to McGill University in Montreal.

Sea ice is frozen ocean water that melts each summer, then refreezes each winter. The amount of summer sea ice in the Arctic has been steadily shrinking over the past few decades because of global warming. Since satellite records began in 1979, summer Arctic ice has lost 40% of its area and up to 70% of its volume, the Guardian said.

In fact, it reached its second-smallest level on record in 2019, the National Oceanic and Atmospheric Administration said.

Sea ice affects Arctic communities and wildlife such as polar bears and walruses, and it helps regulate the planet’s temperature by influencing the circulation of the atmosphere and ocean. It also affects global weather patterns.

“While the Arctic sea ice extent is decreasing during this transition to an ice-free Arctic, the year-to-year variability in extent greatly increases, making life more difficult for local populations and ice-dependent species,” said study co-author Bruno Tremblay of the department of atmospheric and oceanic sciences at McGill.

‘Polar bears may disappear’: Arctic sea ice keeps shrinking. Here’s what that means for the planet

As the climate changes, the Arctic is warming more than twice as fast as the rest of the planet. Arctic air temperatures were about 3.4 degrees above average in 2019 and were the second-warmest since records began in 1900.

Polar bears walk on Arctic sea ice. Sea ice cover is a hunting ground and habitat for polar bears and seals, and keeps the Arctic cool by reflecting sunlight.

How often the Arctic loses its sea ice cover in the future depends on emissions of carbon dioxide, the study said. If emissions are reduced rapidly, ice-free years will occur only occasionally. With higher emissions, the Arctic Ocean will become ice-free in most years.

Thus, even if humans act to reduce emissions dramatically, summer sea ice might still be gone, according to the study.

Sea ice melting:Rising Arctic temps cause sea ice to melt at alarming level, threatening habitats and cultures

“If we reduce global emissions rapidly and substantially, and thus keep global warming below 2 degrees Celsius relative to pre-industrial levels, Arctic sea ice will nevertheless likely disappear occasionally in summer even before 2050,” said study lead author Dirk Notz, who heads the sea ice research group at the University of Hamburg in Germany. “This really surprised us.”

The study analyzed recent results from 40 of the latest climate computer models and involved 21 research institutes from around the world. It was published in the journal Geophysical Research Letters, a publication of the American Geophysical Union.

Arctic may see ice-free summers in as few as 15 years, study says

Summers may be ice-free in the Arctic as soon as 2034, a new study suggests.

  • Sea ice is frozen ocean water that melts each summer, then refreezes each winter.
  • The Arctic is warming more than twice as fast as the rest of the planet.
  • The study used statistical models to predict the future amount of Arctic ice.

Climate change is taking its toll on one of the world’s coldest places.

study suggests that the Arctic “may be essentially ice-free during summer within 15 years.”

The study used statistical models to predict the future amount of Arctic ice, which suggested that the Arctic could be ice-free in the summer during the decade of the 2030s – most likely in the year 2034.

Sea ice is frozen ocean water that melts each summer, then refreezes each winter. The amount of summer sea ice in the Arctic has been steadily shrinking over the past few decades because of global warming. It reached its second-smallest level on record in 2019, the National Oceanic and Atmospheric Administration (NOAA) said.

Sea ice affects Arctic communities and wildlife such as polar bears and walruses, and it helps regulate the planet’s temperature by influencing the circulation of the atmosphere and ocean.

“The extent of Arctic ice is important to Arctic peoples, whose lands are being affected by increased coastal erosion,” NOAA said in a statement. “Conversely, the disappearance of ice creates economic opportunities, including the opening of oil fields and new shipping routes.”

It also affects global weather patterns.

‘Polar bears may disappear:Arctic sea ice keeps shrinking. Here’s what that means for the planet

The study was conducted by scientists at NOAA, the University of Washington, and the North Carolina Institute for Climate Studies.

What scientists refer to as the first “ice-free” Arctic summer year will occur when the Arctic has less than 1 million square kilometers of sea ice. (The thick ice sheets surrounding Canada’s Arctic islands are likely to remain for much longer, even in summer.)

As the climate changes, the Arctic is warming more than twice as fast as the rest of the planet: In fact, Arctic air temperatures were about 3.4 degrees above average in 2019, and were the second-warmest since records began in 1900.

Scientists also said the results of the study indicate that there is room for improvement in sea-ice models – and that the ice may disappear even more quickly than current models suggest.

“Climate models may be collectively underestimating the rate of change,” the authors write in the study.

The study was published in the journal Climate.

Discovery Regarding Arctic Sea Ice and Permafrost Has Significant Implications for the Future

Siberian Cave

Researchers gathering data in a Siberian cave. Credit: University of Oxford

https://scitechdaily.com/discovery-regarding-arctic-sea-ice-and-permafrost-has-significant-implications-for-the-future/

Sea-Ice-Free Arctic Makes Permafrost Vulnerable to Thawing

Permafrost is ground that remains frozen throughout the year; it covers nearly a quarter of Northern Hemisphere land. The frozen state of permafrost enables it to store large amounts of carbon; about twice as much as in the atmosphere. The rate and extent of future thawing of permafrost, and consequent release of its carbon, is hard to predict from modern observations alone.

However, a crucial past relationship between summer sea ice in the Arctic and permafrost, discovered in this study, is now understood, with significant implications for the future.

Professor Gideon Henderson, an author of the study based at the Department of Earth Sciences, University of Oxford, said: ‘We were surprised to find that times when permafrost melted in the past did not simply match up with times when the Earth was at its warmest, but were much more likely when the Arctic was free of ice in the summer. This discovery about the past behavior of permafrost suggests that the expected loss of Arctic sea ice in the future will accelerate melting of the permafrost presently found across much of Siberia.’

Significant decreases of Arctic sea ice have been observed in recent years, and the Arctic is expected to be free of summer sea ice in the coming decades. Such loss of sea ice is likely to lead to an acceleration of thawing of permafrost in Siberia and to the consequent release of carbon.

The new research relies on challenging field work to discover and explore Siberian caves. Caves are powerful recorders of periods when permafrost was absent in the past. Stalagmites, stalactites and flowstones can only form when there is liquid water, and therefore not when overlying land is permanently frozen. The presence of stalagmites in caves under present permafrost thus demonstrate periods when permafrost was absent in the past.

Development of new approaches to date stalagmites using measurements of natural uranium and lead, allow dating of the recovered stalagmites — and therefore of periods of permafrost absence — for the last one and a half million years. Stalagmites grew intermittently from 1,500,000 to 400,000 years ago, and have not grown for the last 400,000 years. The timing of stalagmite formation, and therefore absence of permafrost, do not relate simply to global temperatures in the past but are notably more common when the Arctic Ocean was free of summer sea-ice.

This study shows that several processes may lead to the relationship between Arctic sea-ice and permafrost. The absence of sea ice leads to an increase in heat and moisture transfer from ocean to atmosphere and therefore to warmer air transported far overland into Siberia. Moisture transport also increases snow fall over Siberia during the autumn months. This blanket of snow insulates the ground from the extreme cold of winters leading to an increase in average annual ground temperatures, destabilizing the permafrost. Consequently, in regions with increased snow cover and insulation, permafrost will start to thaw, releasing carbon dioxide that was trapped for millennia.

Reference: “Palaeoclimate evidence of vulnerable permafrost during times of low sea ice” by A. Vaks, A. J. Mason, S. F. M. Breitenbach, A. M. Kononov, A. V. Osinzev, M. Rosensaft, A. Borshevsky, O. S. Gutareva and G. M. Henderson, 8 January 2020, Nature.
DOI: 10.1038/s41586-019-1880-1

The international team involved in the study consists of scientists from the Geological Survey of Israel, The University of Oxford, UK, Northumbria University, UK, The Institute of Earth’s Crust of the Russian Academy of Sciences (Irkutsk, Russia), and the Speleoclub Arabica (Irkutsk, Russia).

First evidence that Antarctica’s thinning ice shelves are causing more ice to move from the land into the sea

https://phys.org/news/2019-12-evidence-antarctica-thinning-ice-shelves.html

First evidence that Antarctica's thinning ice shelves are causing more ice to move from the land into the sea
A detailed view of changes in ice flow around the Pine Island and Thwaites glaciers, due to thinning ice shelves. Pine Island Glacier is at the top right, with changes seen almost 100 miles inland. Credit: Northumbria University

Researchers have produced the first physics-based quantifiable evidence that thinning ice shelves in Antarctica are causing more ice to flow from the land into the ocean.

Satellite measurements taken between 1994 and 2017 have detected  in the thickness of the floating ice shelves that surround the Antarctic Ice Sheet. These shelves buttress against the land-based ice, holding them in place like a safety band.

While it has been suggested that the thinning ice shelves were responsible for a direct loss of ice from the land-based  into the , there was no actual evidence linking data and physics that could demonstrate this, until now.

Researchers in the UK and US have now undertaken the first continent-wide assessment of the impact the thinning ice shelves are having on the flow of ice in Antarctica.

They were particularly interested in seeing how much ice flowed across the ‘grounding line’. This is the point where the land-based ice sheet meets the sea-based ice shelves.

They used a state-of-the-art ice-flow model developed at Northumbria University, UK, and newly available measurements of changes in the geometry of ice shelves to calculate the changes in grounded ice flow.

First evidence that Antarctica's thinning ice shelves are causing more ice to move from the land into the sea
Credit: Northumbria University

When the modelled results were compared with those obtained by satellites over the last 25 years, the researchers found what they described as ‘striking and robust’ similarities in the pattern of ice flowing from the ice sheet into the ocean.

The largest impact was found in West Antarctica, which already makes a significant contribution to sea level change. The largest changes are taking place around the Pine Island and Thwaites glaciers. On Pine Island Glacier, evidence of these changes could be seen almost 100 miles (150km) inland, upstream of the grounding line.

Hilmar Gudmundsson, Professor of Glaciology and Extreme Environments at Northumbria University led the study. He said there has been a long-standing question as to what was causing the changes we have observed in land-based ice over the last 25 years, and that while the thinning of the floating ice-shelves had been suggested as a reason, the idea had never been put to the test before now.

“I found it striking how well our modelled changes agree with the pattern of observed ,” he said.

“There are other processes in play as well, but we can now state firmly that the observed changes in ice-shelves do cause significant changes over the grounded ice, speeding up its flow into the ocean.”

A critical element of the findings was the speed at which the ice flowed from the sheet into the ocean as a result of the thinning ice shelves.

“One of the most important lessons from this study is that the impact is felt without any delay,” said Professor Gudmundsson.

First evidence that Antarctica's thinning ice shelves are causing more ice to move from the land into the sea
Credit: Northumbria University

“Generally, we distinguish between an instantaneous response or a delayed, transient response. Our study shows the thinning of the ice shelves results in a significant instantaneous response to ice flow and ongoing mass loss. This means that we are not protected against the impact of the Antarctic Ice Sheet on global sea levels by a long response time.”

He added: “This study closes an important hole in our understanding. Lack of data and limitations in modelling previously made it challenging to quantify the importance of ocean-induced changes as a driver for ongoing mass loss, but we have now shown that the observed ice shelf changes do indeed impact on upstream flow significantly.”

The research was led by Northumbria University, Newcastle in the UK, with the NASA Jet Propulsion Laboratory and the Scripps Institution of Oceanography at the University of California San Diego.

Helen Amanda Fricker, Professor at Scripps Institution of Oceanography, said: “Ice shelves are the most vulnerable parts of Antarctica’s ice sheet system and we know that they are shrinking, but what we didn’t know before this work was how that was impacting the grounded ice behind them.”

Fernando Paolo, postdoctoral scholar at Jet Propulsion Laboratory/California Institute of Technology, added: “It is striking how far inland the changes in ice shelves can impact the ice sheet flow. Since we now know that shrinking ice shelves are directly responsible for increases in ice discharge to the ocean, it is important that we keep monitoring them to watch how they evolve.”

It is believed that the ice shelves may be thinning due to changes in ocean heat content, either by ocean warming or from changes in how the ocean circulates around and below the shelves, but further research is needed to establish the specific reasons.

The study, Instantaneous Antarctic ice-sheet mass loss driven by thinning  is published in Geophysical Research Letters.


Explore further

Tiny ice losses at Antarctica’s fringes can accelerate ice loss far away

Studying The Ripple Effects Of Shrinking Arctic Sea Ice

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Scientists on the research vessel Akademik Fedorov spent a week or so setting up a network of scientific monitoring equipment up to about 25 miles from the MOSAiC ship.

Ravenna Koenig/NPR

Arctic sea ice is one of the most dramatic indicators of the changing climate. Ice cover on the Arctic Ocean is in some months about half what it was decades ago, and its thickness has shrunk, by some estimates 40%.

Changes in the ice may also mean a host of other changes, in the Arctic system and around the globe. To better understand this, scientists have frozen an icebreaker alongside an Arctic ice floe that they will observe for a whole year.

The project is called MOSAiC, for Multidisciplinary drifting Observatory for the Study of Arctic Climate. And the primary questions they’re trying to answer: what are the causes of diminishing Arctic ice, and what are the consequences?

At just about 5 degrees from the North Pole, ocean physicist Tim Stanton from the Naval Postgraduate School stands next to a hole in the ice, surrounded by boxes of tools and equipment.

“I’ve got to just get the ‘hair dryer,'” he says, eyeing two electrical connectors for a science buoy that need to be warmed up in the 18 degrees Fahrenheit temperature.

A hair dryer? He clarifies: “Well, it’s an electrical what-do-you-call-it… heat gun,” he says. “It will frizz your hair, that’s for sure!”

Stanton is in the middle of a grueling eight hour process to install the buoy about 15 miles from the spot where the MOSAiC ship, the German icebreaker Polarstern, is moored.

It’s part of a network of equipment that’s being distributed around the Polarstern and will operate independently throughout the next year. It will provide additional data to what’s being collected at the central research camp on the ice next to the ship.

Ocean physicist Tim Stanton with the buoy system he’s installing in the ice. The aim is to get a better sense of the ocean factors that may be driving Arctic ice melt.

Ravenna Koenig/NPR

The buoy is a big banana yellow device, with a whole bunch of scientific bells and whistles that hang below it in the water.

“The flux package mounts on here,” says Stanton, pointing to a cylindrical instrument with sensors on it that will run up and down a metal rail hanging vertically in the water. “And that’s what measures the transport of heat, salt and momentum in the water column.”

Stanton wants to collect data on those attributes of the ocean because he thinks it may help explain why sea ice is disappearing as fast as it is.

“At first glance it must be obvious, right? You add heat, you melt ice,” he says. “But it is so complicated.”

As more sea ice melts in the summertime, it’s contributing fresher water to the top of the ocean. The saltier ocean water, which sits lower because it’s more dense, can create a barrier that prevents the fresher water from going down.

If that top water is trapped near the surface all summer, Stanton thinks it can absorb a lot more heat from the sun, and lead to even more ice melting.

“You can get these fresh warm layers that, when a little bit of wind comes along, does a little bit of mixing, really melts the heck out of the ice,” he says.

Tim Stanton installing a science buoy with the help of student Rosalie McKay. The buoy will measure heat, salt and momentum in the upper layer of the ocean over the course of a year.

Ravenna Koenig/NPR

While Stanton is asking questions about things that are going on below the ice, other scientists are looking at things going on above it.

Jessie Creamean of Colorado State University, for example, is out on the ice testing a device that collects and counts tiny particles in the atmosphere called aerosols.

“Alright little aerosol sampler, do well today,” Creamean says, closing a pelican case about the size of a carry-on piece of luggage. She’s tested it before in Colorado, but today’s experiment is to see how well it does in the cold.

People may be most familiar with aerosols created by pressurized cans like hairspray, but that’s just one kind. Aerosols can also come from natural sources like dust, pollen, fungi, or sea salt, and they’re actually the seeds that clouds need to form and grow.

In the Arctic, scientists think that microbes in the ocean, like bacteria or algae, can generate aerosols. And Creamean hypothesizes that less ice on the Arctic Ocean could mean more aerosols getting blown from the water into the atmosphere, and seeding more clouds.

Scientist Jessie Creamean moves a portable aerosol sampler out onto the ice to test it in the cold conditions.

Ravenna Koenig /NPR

The mechanism for that could be twofold: through more sunlight getting to the ocean as sea ice decreases, and potentially causing more growth of microbes, and also through the increased contact between the ocean and atmosphere.

MOSAiC scientists are interested in clouds because they’re important for regulating temperature, similar to a thermostat. Depending on the season, whether clouds are over water or ice, and the properties of the clouds, they can wind up cooling or warming the earth below.

Scientist Jessie Creamean and her portable aerosol sampler in the lab on the research vessel Akademik Fedorov.

Ravenna Koenig/NPR

“That affects how much heat can basically help melt the sea ice, or it can actually reflect sunlight from the sea ice,” says Creamean. “So it has a big role in controlling how much sea ice we have here.”

Creamean and Stanton are among hundreds of scientists from different disciplines trying to better understand this changing region.

“We’re looking at the interactions in the system,” says Matthew Shupe, an atmospheric scientist with the University of Colorado and the National Oceanic and Atmospheric Administration, and one of the coordinators for the expedition.

“How the atmosphere interacts with the sea ice, how the ocean interacts with the sea ice, the ecosystem, the biogeochemical processes,” he says.

The overarching goal of collecting all this data is to improve the way the Arctic is represented in climate models. Those are the computer simulations scientists use to estimate things like how much the earth could warm in the next 50 years.

The better you reflect how reality works in simulation, the better a prediction you’ll get. But because so little is known about how the Arctic Ocean system works, Shupe says predictions for how the Arctic will respond to climate change vary significantly.

The primary questions MOSAiC is asking: what are the causes and consequences of diminishing Arctic sea ice?

Ravenna Koenig/NPR

“The Arctic is a place where the models agree the least,” he says. “So that tells us that we’re missing something.”

Projecting changes in the Arctic — such as when the Arctic Ocean will see its first ice-free summer — is obviously important for the local ecosystem, for Arctic communities, and for anyone interested in doing commercial activity in the region.

But this research will also help scientists figure out how changes in the Arctic will impact other places on earth. For example, it may contribute to scientists’ understanding of the possible connections between warming in the Arctic and extreme weather events at mid-latitudes.

“We need to understand the physics, and ultimately improve our models that can help answer those questions for us,” says Shupe.

It will also help scientists anticipate the speed at which the Greenland ice sheet could melt, raising global sea level, and improve projections for how much global temperature will rise in the coming years.

By drifting across the Arctic Ocean for the next year and observing how all the smaller pieces of the Arctic system fit together, scientists hope they can bring these big picture questions into clearer focus.

Across Arctic Canada, sea ice levels are again at record lows

Across Arctic Canada, sea ice levels are again at record lows

“We could be up to a month behind where we should be at this time of year”

“Freeze-up is very, very late this year,” says Gjoa Haven’s Willie Aglukkaq, who took this photo on Oct. 18. “Can still drive boats to mainland, which is very unusual for Gjoa Haven. Never seen the ocean open this late in my lifetime.” (Photo by Willie Aglukkaq)

By Dustin Patar

Last October, when Juuta Sarpinak of Igloolik set off on a seal hunt, he took his snowmobile. For the same trip exactly a year later, he’d need a boat.

Across Nunavut and the rest of the Arctic, the same scenario is playing out.

“It’s the latest I’ve ever seen it freeze up in my lifetime,” said Willie Aglukkaq, who’s lived in Gjoa Haven for nearly 40 years.

He’s right.

As of Oct. 15, sea ice levels hit 5.118 million square kilometres, making them the lowest on record, which began in 1968.

“Depending on the area, we could be up to a month behind where we should be at this time of year,” said Gilles Langis, senior ice forecaster with the meteorological service of Canada.

But it’s not the first time this year ice levels have been at record lows.

April also saw the least amount of sea ice ever recorded.

This was then followed by a record-setting July.

In August, the ice loss slowed.

“We were tied for the second-lowest [amount of ice] with 2007 and 2016, but quite a bit above 2012,” said Walt Meier, a senior research scientist at the National Snow and Ice Data Center.

“But now we’re actually below 2012 levels for this time of year because it’s a slow freeze-up—2012 recovered pretty quickly, but we’ve been very sluggish in growing ice this year.”

As of Oct. 15, sea ice levels dropped below those from 2012, which previously held the record. (Graph courtesy of the NSIDC)

With sea ice growth, the big driver is air temperature.

“If you have an area of open water and the temperatures above it are cooler than the water temperature, it’ll lose heat into the atmosphere and the water will start cooling off to the point where it reaches freezing,” said Langis.

But Arctic air temperatures through October have been unseasonably warm, much like the previous six months.

“It was a pretty extreme summer,” said Meier.

From April onward, every month has ranked in the top three warmest—in terms of Arctic air temperature—on record, with May and August now holding top spots.

According to Meier, because of this, there was an abundance of ice-free water throughout the summer that absorbed a lot of solar energy and warmed up quite a bit.

“That heat is just taking a while to dissipate into the atmosphere and for the ocean to cool enough to grow ice.”

(Photo courtesy of UNEP)

What’s going on this year is representative of something larger.

“Under the influence of global heating caused by human-induced greenhouse gases emissions, we have seen a sharp decrease in the extent of Arctic sea [ice] since 1979,” says Pascal Peduzzi, Director of GRID-Geneva, in a press release published by the UN Environment Programme (UNEP).

Much like the scenario currently playing out across the Arctic this year, declining sea ice has amplified Arctic warming over the last several decades.

According to the press release, “Temperatures increased by around 0.5°C per decade between 1982 and 2017, primarily due to increased absorbed solar radiation accompanying sea ice loss since 1979. This is twice as fast as the global average.”

This season isn’t an exception.

But while the year-to-year trend continues on, ice coverage this year is on the rebound.

“It’s just finally starting to freeze,” said Aglukkaq.

Over the last 10 days, since Oct. 20, sea ice coverage has increased by almost 1.5 million square kilometres, including the water near Gjoa Haven.

If the current pace of ice growth continues, 2019 may soon once again be above 2012 levels.

315 billion-tonne iceberg breaks off Antarctica

Iceberg calvingImage copyrightCOPERNICUS DATA/SENTINEL-1/@STEFLHERMITTE
Image captionThe EU’s Sentinel-1 satellite system captured these before and after images

The Amery Ice Shelf in Antarctica has just produced its biggest iceberg in more than 50 years.

The calved block covers 1,636 sq km in area – a little smaller than Scotland’s Isle of Skye – and is called D28.

The scale of the berg means it will have to be monitored and tracked because it could in future pose a hazard to shipping.

Not since the early 1960s has Amery calved a bigger iceberg. That was a whopping 9,000 sq km in area.

Amery is the third largest ice shelf in Antarctica, and is a key drainage channel for the east of the continent.

The shelf is essentially the floating extension of a number of glaciers that flow off the land into the sea. Losing bergs to the ocean is how these ice streams maintain equilibrium, balancing the input of snow upstream.

So, scientists knew this calving event was coming. What’s interesting is that much attention in the area had actually been focussed just to the east of the section that’s now broken away.

This is a segment of Amery that has affectionately become known as “Loose Tooth” because of its resemblance in satellite images to the dentition of a small child. Both ice areas had shared the same rift system.

Loose ToothImage copyrightNASA
Image captionLoose Tooth pictured in the early 2000s. D28 is seen forming to the left

But although wobbly, Loose tooth is still attached. It’s D28 that’s been extracted.

“It is the molar compared to a baby tooth,” Prof Helen Fricker from the Scripps Institution of Oceanography told BBC News.

Prof Fricker had predicted back in 2002 that Loose Tooth would come off sometime between 2010 and 2015.

“I am excited to see this calving event after all these years. We knew it would happen eventually, but just to keep us all on our toes, it is not exactly where we expected it to be,” she said.

The Scripps researcher stressed that there was no link between this event and climate change. Satellite data since the 1990s has shown that Amery is roughly in balance with its surroundings, despite experiencing strong surface melt in summer.

“While there is much to be concerned about in Antarctica, there is no cause for alarm yet for this particular ice shelf,” Prof Fricker added.

Amery ice shefImage copyrightRICHARD COLEMAN/UTAS
Image captionAmery experiences a lot of summer surface melt, but the data indicates it is in equilibrium

The Australian Antarctic Division will however be watching Amery closely to see if it reacts at all. The division’s scientists have instrumentation in the region.

It’s possible the loss of such a big berg will change the stress geometry across the front of the ice shelf. This could influence the behaviour of cracks, and even the stability of Loose Tooth.

D28 is calculated to be about 210m thick and contains some 315 billion tonnes of ice.

The name comes from a classification system run by the US National Ice Center, which divides the Antarctic into quadrants.

The D quadrant covers the longitudes 90 degrees East to zero degrees, the Prime Meridian. This is roughly Amery to the Eastern Weddell Sea.

D28 is dwarfed by the mighty A68 berg, which broke away from the Larsen C Ice Shelf in 2017. It currently covers an area more than three times as big.

Nearshore currents and winds will carry D28 westwards. It’s likely to take several years for it to break apart and melt completely.

Running the numbers on an insane scheme to save Antarctic ice

SLIPPERY SLOPE —

It would take a lot. Like a real lot.

Antarctica's Pine Island Glacier sheds some icebergs. Could we... sort of... put them back?
Enlarge / Antarctica’s Pine Island Glacier sheds some icebergs. Could we… sort of… put them back?

Imagine, if you will, the engineers of the king’s court after Humpty Dumpty’s disastrous fall. As panicked men apparently competed with horses for access to the site of the accident, perhaps the engineers were scoping out scenarios, looking for a better method of reassembling the poor fellow. But presumably none of those plans worked out, given the dark ending to that fairy tale.

A recent study published in Science Advances might be relatable for those fairy tale engineers. Published by Johannes Feldmann, Anders Levermann, and Matthias Mengel at the Potsdam Institute for Climate Impact Research, the study tackles a remarkable question: could we save vulnerable Antarctic glaciers with artificial snow?

Keeping our cool

Antarctica’s ice is divided into two separate ice sheets by a mountain range, with the smaller but much more vulnerable West Antarctic Ice Sheet representing one of the biggest wildcards for future sea level rise. In 2014, a study showed that two of the largest glaciers within that ice sheet—known as the Pine Island Glacier and Thwaites Glacier—had likely crossed a tipping point, guaranteeing a large amount of future ice loss that would continue even if global warming were halted today.

Much of the bedrock beneath the West Antarctic Ice Sheet is actually below sea level, though it’s buried below kilometers of solid ice. This makes for situations where the bed beneath the ice slopes down as you go inland from the coast. That’s inherently unstable, and once a glacier starts retreating downslope, the invading water provides an increasing floating force that reduces the sliding friction that slows the seaward flow of ice.

In the case of the Pine Island and Thwaites Glaciers, it seems that this is exactly what’s happening. Although this process can take centuries to fully play out, this portion of the ice sheet contains enough ice to raise global sea level by more than a meter.

Is there some extraordinary measure that could prevent that loss and preserve these glaciers? It’s the kind of question people will often ask, and scientists (who know the scale of these things) generally ignore as implausible.

But in this case, the researchers decided to go wild. Using a computer model of the ice sheet, they simulated the effects of adding huge amounts of ice near the front of these two glaciers. The idea works like this: Where a glacier meets the sea, it transitions from grounded to floating. Behind this “grounding line,” the glacier sits on the bedrock and sediment beneath; in front it gets thinner and floats as an ice shelf. To preserve the glacier, you need to keep that grounding line from retreating downhill. Thicken the ice on the inland side of the grounding line, and the thickness of ice flowing over the line and into the ice shelf increases—its weight keeps the grounding line pinned in place.

This map shows bedrock elevation beneath the ice sheet, with the white box highlighting the area of the Pine Island and Thwaites Glaciers where snow would be added in this scenario.
Enlarge / This map shows bedrock elevation beneath the ice sheet, with the white box highlighting the area of the Pine Island and Thwaites Glaciers where snow would be added in this scenario.

The researchers played around with different amounts of ice added to the glaciers for different periods of time, ranging from 10 year treatments to 50 years. Spreading it out over a longer period could mean a less preposterous addition of ice each year, but they found that the total amount has to increase if you do it that way. So in the end, the scenario they selected was 7,400 billion tons of ice added over 10 years. That was enough to restabilize these glaciers, preventing their inexorable decline.

Two for one special

To put that into context, removing that much seawater from the ocean would lower global sea level by about 2 millimeters per year. Current total sea level rise is a little over 3 millimeters per year, so it would be like nearly halting sea level rise… by bailing water out of the ocean. We can call that a bonus positive.

This analysis is more about what it would take than what such a scheme would look like, but the basic options are to pump water up and hose it around—hoping it freezes quickly—or to freeze it into snow like the world’s most awkwardly located ski resort.

Here, the researchers transition to listing all the reasons this is impractical and all the negative impacts it could have. For starters, the seawater would have to be desalinated since salt would probably affect the physics and behavior of the ice. Simply pumping that much water up the 640 meters and spreading it over an area nearly the size of West Virginia would require the power of something like 12,000 wind turbines—and that’s without the very substantial energy requirements for desalination and snow-making.

“The practical realization of elevating and distributing the ocean water would mean an unprecedented effort for humankind in one of the harshest environments of the planet,” the researchers write.

The impacts on Antarctic ecosystems could also be huge. Pumping that water out of the sea near the coast would significantly alter the circulation of water, which might even become somewhat self-defeating, as it could bring more warm water up against the ice shelf, increasing melt.

In the Potsdam Institute’s press release, Levermann puts it this way: “The apparent absurdity of the endeavour to let it snow in Antarctica to stop an ice instability reflects the breath-taking dimension of the sea-level problem. Yet as scientists we feel it is our duty to inform society about each and every potential option to counter the problems ahead.”

And to be clear, this is in addition to halting climate change—the scenario the numbers are based on assumes the temperatures don’t keep rising. But as the alternative is eventual inundation of parts of the world’s coastal cities, an argument can be made that the cost could be worth paying. It least it gives us an idea just how hard it would be to put Humpty Dumpty back together again.

When is Arctic ice like a magnet?

Arctic meltponds
Arctic meltponds (Image courtesy: Kenneth Golden)

model that simulates magnets can also reproduce pools of water on Arctic sea ice from just one real-world measurement. Researchers in the US and UK adapted the Ising statistical model of phase transitions in ferromagnets to recreate melt-pond patterns. Characterizing the distribution of meltwater at small scales could improve climate models and predict ice loss better.

As climate changes, warming is expected to be especially rapid at high latitudes. In the Arctic, a lengthening melt season over the last few decades has already reduced the volume and extent of sea ice, with year-on-year ice-loss rates generally exceeding predictions.

One reason for the failure of models to predict this loss accurately might lie in how they account for melt ponds. The formation and growth of these ponds, which occurs at the transition between sea ice and open ocean, includes a positive feedback loop that makes the system especially sensitive.

“Pond evolution largely controls sea-ice albedo, a key parameter in climate modelling and one of the most important — and least understood — processes in determining the role of sea ice in the climate system,” says Kenneth Golden of the University of Utah, US.

Real-life and modelled meltponds

As melt ponds form on the sea-ice surface, highly-reflective ice and snow are replaced by darker pools of water. The meltwater absorbs more solar radiation and warms up more than the ice that it replaces; the extra energy can trigger additional melting in its surroundings. When the melt pond penetrates the full thickness of the ice, warmer ocean water floods in from below, accelerating the process.

Existing descriptions of pond formation in global climate models consider the overall volume of meltwater but not its surface distribution. Yet, because the albedo change caused by melt ponds is a surface process, and because the rate at which ponds conduct heat to their surroundings depends on their perimeter, understanding the rules governing melt pond sizes is crucial for climate modelling.

Sea-ice spin

The standard Ising model comprises a lattice of interacting particles, each of which is assigned a spin value that is either up or down. To capture the detailed geometry of melt ponds, Golden, with colleagues at Northumbria University, UK, the University of Dayton, US, and the University of Utah, US, created a version where the lattice represents the sea-ice surface, and each node a pixel of either ice or liquid water.

Starting with a random input configuration that does not resemble the real-world, each node interacts with its neighbours until the system settles on a local low-energy state. With a lattice spacing of 1 metre – the length scale over which Arctic ice exhibits significant topographic differences – the pattern that emerges from the energy-minimization process closely matches the melt-pond distribution seen in real life. For example, both real and modelled ponds scale in size according to the same power law, and both form more complex, fractal shapes when they grow larger than 100 sq. m.

brightrecruits.com/jobs/laser-development-engineer-2Advertisement“The approach could ultimately lead to a framework for representing pattern formation occurring at spatial scales smaller than the grid spacing used in global climate models, which currently track meltwater volume without representing its spatial distribution,” says Golden.

Other parameters that describe ferromagnetic behaviour in the original Ising model also have real-world analogues in the version adapted for sea-ice. The global magnetic field, for example, which conventionally governs how likely particle spins are to align as up or down, now corresponds to solar energy input, making each lattice point more or less likely to be water or ice. The strength of coupling between neighbouring particle spins, meanwhile, now describes heat flow between water and ice in adjacent pixels.

Although Golden and colleagues ran their model with zero global field and an infinite coupling strength, changing these parameters after the initial process could perturb a realistic pond arrangement from its metastable state into an alternative low-energy configuration. In this way, the researchers might simulate how sea ice evolves as melt ponds respond to changing environmental conditions.

Golden and colleagues reported their findings in New Journal of Physics.