Global Warming

NASA Satellite Spots Mile-Long Iceberg Breaking Off of Antarctic Glacier

A massive, 1-mile-long (1.6 kilometers) chunk of ice has broken off Antarctica’s fast-changing Pine Island Glacier, and NASA satellites captured the dramatic event as the icy surface cracked and ripped apart.

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Pine island glacier

Global Warming

Collapsing Beauty: Image of Antarctica’s Larsen Ice Shelf

An expansive new image shows the changes in Antarctica’s Larsen Ice Shelf since the mid-1980s.

The story is one of retreat, and the ice continues to crumble. A growing crack in a portion of the ice shelf called Larsen C is poised to free an iceberg the size of Delaware from the continent.

Larson C isn’t visible in the new satellite image, which focuses on two more northerly portions of the sheet, Larsen A and Larsen B. Ice shelves are floating mattresses of ice that form from the outflow of the glaciers that creep slowly across the Antarctic continent. The Larsen Ice Shelf is on the northeast coast of the Antarctic Peninsula along the Weddell Sea. It was named for the Norwegian explorer Carl Anton Larsen, who explored parts of it in 1893 by ship and ski.

Since 1995, the Larsen Ice Shelf has lost 75 percent of its mass, according to the National Snow and Ice Data Centre (NSIDC). In 1995, a 579-square-mile (1,500 square kilometres) chunk of Larsen A broke off from the ice shelf, according to NASA’s Earth Observatory. In 2002, an even larger portion of Larsen B — 1,255 square miles (3,250 square km) crumbled away. While calving events are normal, collapses of this magnitude have only been seen in the last 30 years, according to the NSIDC.

The collapse of floating ice doesn’t raise sea levels, but a 2004 study by NSIDC researchers found that in the wake of Larsen B’s 2002 collapse, the land-based glaciers that feed the ice sheet have accelerated their flow toward the sea. This speedy flow of ice does have the ability to raise sea levels.

Larsen ice shelf years

Global Warming

Antarctica’s Larsen C Ice Shelf Rift Growing Rapidly

The large rift in the Larsen C Ice Shelf that we reported on a few weeks ago has continued to grow at a rapid rate since then, with a further 10 kilometres of length added since January 1st according to the researchers at the MIDAS Project.

The rift continues to run parallel to the shelf edge, though, so the distance holding the iceberg to the shelf (20 kilometres) remains the same as the last time that we reported on it. Obviously, though, as the images below show, even if the rift continues to run parallel, it will inevitability lead to an iceberg calving event.

This matters because, according to the researchers at the MIDAS Project, once the 5,000 sq. km iceberg calves, it will destabilize the whole Larsen C Ice Shelf — possibly leading to the disintegration of the whole ice shelf. The Larsen B Ice Shelf disintegrated in 2002 following a similar event as the one occurring now.

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Global Warming

Vast Iceberg poised to crack off Antarctica

A rift, slowly developing across the Larsen C ice shelf on the Antarctic Peninsula in recent years, expanded abruptly last month, growing by about 18 km. It is now more than 80 km long with just 20 km left before it snaps, scientists said.

“The Larsen C Ice shelf in Antarctica is primed to shed an area of more than 5,000 square km following further substantial rift growth,” scientists at Project Midas at the University of Swansea in Wales said in a statement.

The iceberg “will fundamentally change the landscape of the Antarctic Peninsula” and could herald a wider break-up of the Larsen C ice shelf, the statement said.

Ice shelves are areas of ice floating on the sea, several hundred metres thick, at the end of glaciers. Scientists fear the loss of ice shelves around the frozen continent will allow glaciers inland to slide faster towards the sea as temperatures rise because of global warming, raising world sea levels.

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Global Warming

Global Warming Takes A Toll On Antarctica: Ice Sheet Is Melting From Surface Down

East Antarctica’s massive ice sheet may be more exposed to global warming than previously thought, a new study suggests.

Antarctica and global warming

In 2014, scientists were left baffled when they found a huge, 2-mile-wide circle over an Antarctic ice shelf. Some speculated that a meteorite may have caused it. Now, a new study by researchers from Belgium and Netherlands revealed that strong warm winds can erode the ice shelf in the eastern peninsula of Antarctica.

Published in the journal Nature Climate Change, the researchers visited the circle on foot for the first time and they found a deep depression with raised edges. In the centre, there were three moulins, which are vertical well-like shafts in the ice, which drains two melt water streams.

They drilled through the ice and found what they called “englacial” lakes, which is water sandwiched between the ice’s surface and its base, Washington Post reports. In fact, the researchers discovered 55 lakes on or in the ice shelf.

The research team combined climate models, satellite data and on-site measurements. They concluded that strong winds carrying warm air were blowing away reflective snow, paving way for the rays of the Sun to be absorbed into the ice, rather than bouncing back into space.

These winds, which often blow in one direction over the ice sheet, erode the surface snow, exposing the blue ice underneath. Usually, the erosion is compensated by the formation of fresh snow and ice from above. However, oceans are absorbing excess heat generated by global warming, increasing the global air temperatures by 1 degree Celsius.

The frightening part of the discovery shows that even though the Antarctic ice sheet is a sold mass of ice, it has vulnerabilities and weaknesses in some of its parts. There is a greater potential of collapse, and when this happens, the glacial ice behind it flows more quickly to the ocean, increasing sea levels.

Wildlife

Coast of Antarctica Will Host World’s Largest Marine Reserve

The world’s biggest marine reserve, almost as large as Alaska, will be established in the Ross Sea in Antarctica under an agreement reached by representatives of 24 nations and the European Union in Australia on Friday.

The policy makers and scientists agreed unanimously to create a zone that will encompass 600,000 square miles of ocean. Commercial fishing will be banned from the entire area, but 28 percent of it will be designated as research zones, where scientists can catch limited amounts of fish and krill, tiny invertebrates that provide food for whales, penguins, seals and other animals.

The area, which is mostly contiguous and hugs the coast off the Ross Sea ice shelf, will come under protection on Dec. 1, 2017, and remain a reserve for 35 years. The agreement was reached in Hobart, Tasmania, at the Commission for the Conservation of Antarctic Marine Living Resources.

The reserve includes the Ross Sea shelf and slope, the Balleny Islands and the ocean around two seamounts, one known as the Scott seamount. Seamounts, or underwater mountains, are habitats and foraging areas for mammals, birds and fish, including Weddell seals, killer whales and emperor penguins.

This Bird Can Remain Airborne For 10 Months Straight

Scientists have long suspected that the common swift remains airborne for extraordinary amounts of time during its annual migration.

Now, a team of scientists in Sweden has proved that these birds fly for tremendously long periods of time. They affixed data loggers onto a total of 19 of the master fliers in 2013 and 2014, and recaptured the birds months or years later. Researchers found that the birds can spend almost their entire 10-month nonbreeding period on the wing.

The data loggers gathered information on acceleration and flight activity, and those installed in 2014 also included light trackers for geolocation.

The results were astonishing. For example, according to research published in Current Biology, one of the birds stopped for just four nights in February in 2014 — and the next year it stopped for only two hours. Other birds stopped for longer periods of time. But “even when swifts settle to roost,” the researchers say, “the amount of time not flying is very small.”

The birds are known to travel from Europe to sub-Saharan Africa — but they apparently don’t touch down there, as National Geographic reports. Researchers say they have never found roosting sites in sub-Saharan Africa.

The scientists say that the rarity of the stops during nonbreeding season suggests that the bird may only take a pause because of bad weather. The fact that some birds fly continuously during nonbreeding periods indicates that the species may not actually need to land for sleep. In fact, it’s unclear “when and to what extent swifts need to sleep,” the paper states.

“They feed in the air, they mate in the air, they get nest material in the air,” researcher Susanne Åkesson from Lund University in Sweden tells National Geographic. “They can land on nest boxes, branches, or houses, but they can’t really land on the ground.”

The birds’ shape contributes to this finding; their “wings are too long and their legs are too short to take off from a flat surface,” the magazine reports.

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Global Warming

Antarctica is gaining ice: NASA

An increase in Antarctic snow accumulation that began 10,000 years ago is currently adding enough ice to the continent to outweigh the increased losses from its thinning glaciers.

Areas of the continent like the Antarctic peninsula have increased their mass loss in the last decades, says a new NASA study.

The research challenges the conclusion of other studies, including Intergovernmental Panel on Climate Change’s 2013 report which says that Antarctica is overall losing land ice.

According to the analysis of satellite data, the Antarctic ice sheet showed a net gain of 112 billion tonnes of ice a year from 1992 to 2001. The net gain slowed to 82 billion tonnes of ice per year between 2003 and 2008.

“We are essentially in agreement with other studies that show an increase in ice discharge in the Antarctic peninsula and the Thwaites and Pine Island region of West Antarctica,” explained Jay Zwally, glaciologist with NASA Goddard Space Flight Centre in Greenbelt, Maryland.

Our main disagreement is for East Antarctica and the interior of West Antarctica. “Here, we see an ice gain that exceeds the losses in the other areas,” he added. But it might take a few decades for Antarctica’s growth to reverse, according to Zwally.

The study analysed changes in the surface height of the Antarctic ice sheet measured by radar altimeters on two European Space Agency satellites and by the laser altimeter on NASA’s Ice, Cloud, and land Elevation Satellite (ICESat).

“At the end of the last Ice Age, the air became warmer and carried more moisture across the continent, doubling the amount of snow dropped on the ice sheet,” Zwally noted.

“The good news is that Antarctica is not currently contributing to sea level rise, but is taking 0.23 mm per year away,” Zwally said. But this is also bad news.

“If the 0.27 mm per year of sea level rise attributed to Antarctica in the IPCC report is not really coming from Antarctica, there must be some other contribution to sea level rise that is not accounted for,” he pointed out in the study which appeared in the Journal of Glaciology.

Global Warming

Sea Ice Around Antarctica Declines in 2015 Peak

The sea ice around Antarctica grew to its annual peak on Oct. 6 but showed a sharp decline from the record coverage of recent years.

NASA says this year’s maximum fell roughly in the middle of what has been measured during the past 37 years of satellite observations.

Scientists said the developing El Niño probably had a strong influence on this year’s sea ice.

Rather than being in sharp contradiction to a warming climate, a greater amount of ice ringing Antarctica in the recent past has been linked to climate change.

Stronger southern hemisphere winds due to a warmer climate appear to have caused the floating ice to bunch up around Antarctica rather than drifting northward and melting.

“After three record high extent years, this year marks a return toward normalcy for Antarctic sea ice,” said Walt Meier, a sea ice scientist at Goddard.

“There may be more high years in the future because of the large year-to-year variation in Antarctic extent, but such extremes are not near as substantial as in the Arctic, where the declining trend towards a new normal is continuing,” Meier added.

Satellite data composite of Antarctic sea ice maximum on October 6, 2015.

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Global Warming

Antarctic Ice Shelf in Last Throes of Collapse

A vast Antarctica ice shelf that partly collapsed in 2002 has only a few years left before it fully disappears, according to a new study.

Radar data reveals that the Larsen B ice shelf could shatter into hundreds of icebergs by 2020, researchers reported Thursday (March 14) in the journal Earth and Planetary Science Letters.

“It’s really startling to see how something that existed on our planet for so long has disappeared so quickly,” lead study author Ala Khazendar, a scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California, told Live Science.

An ice shelf is like a floating ice plateau, fed by land-based glaciers. The Larsen B ice shelf existed for 12,000 years before it fell apart in 2002, separate studies showed. The ice shelf is on the Antarctica Peninsula, the strip of land that juts northward toward South America. Larsen B is about half the size of Rhode Island, some 625 square miles (1,600 square kilometres).

Because the ice shelf is already in the ocean, its breakup won’t further boost sea level rise. But Khazendar and his co-authors also discovered that the glaciers feeding into Larsen B’s remaining ice shelf have dramatically thinned since 2002.

“What matters is how much more ice the glaciers will dump into the ocean once this ice shelf is removed,” Khazendar said. “Some of these glaciers are most likely already contributing to sea level rise because they are in the process of accelerating and thinning.”

The Leppard and Flask glaciers thinned by 65 to 72 feet (20 to 22 meters) between 2002 and 2011, the new study reported. The fastest-moving part of Flask Glacier sped up by 36 percent, to a speed of 2,300 feet (700 m) a year.

The glaciers that were behind the vanished section of the Larsen B ice shelf sped up by as much as 8 times their former rate after the ice crumbled over a six-week period in 2002, earlier studies showed.

The northwestern part of the Larsen B ice shelf is also becoming more fragmented, the researchers said. But the southeastern part is cracking up. A huge rift has appeared just 7.5 miles (12 km) from the grounding line, where the ice loses contact with the ground and starts floating on the ocean, the study reported. This crack marks where the ice shelf may start to break apart, the researchers said.

The Antarctica Peninsula is one of the world’s fastest-warming places, with an average rise in air temperature of 5 degrees Fahrenheit (2.8 degrees Celsius) in the past 50 years, according to the British Antarctic Survey. This March, the northern tip of the peninsula set an unofficial heat record of slightly above 63 F (17 C).

Researchers think the surface warming is melting the ice shelves, triggering a cascade of events that eventually leads them to catastrophically collapse. But recent research also points to melting from below, from warmer ocean water.

Environment

Warmest Temperature Ever Recorded On The Continent Of Antarctica

The warmest temperature ever recorded on the continent of Antarctica may have occurred on Tuesday, March 24, when the mercury shot up to 63.5°F (17.5°C) at Argentina’s Esperanza Base on the northern tip of the Antarctic Peninsula.

The previous hottest temperature recorded in Antarctica was 63.3°F (17.4°C) set just one day previously at Argentina’s Marambio Base, on a small islet just off the coast of the Antarctic Peninsula. Prior to this week’s remarkable heat wave, the hottest known temperature in Antarctica was the 62.6°F (17.0°C) recorded at Esperanza Base in October 1976.

The World Meteorological Organization has not yet certified that this week’s temperatures are all-time weather records for Antarctica, though the Argentinian weather service has verified that the temperatures measured at Esperanza Base and Marambio Base were the highest ever measured at each site.

The Antarctic Peninsula is one of the fastest warming spots on Earth. While the Earth as a whole warmed up by 1.3°F between 1900 and 2011, the Antarctic Peninsula warmed by 5°, forcing massive ice shelves to disintegrate and penguin colonies to collapse. A 2012 paper in Nature found that the recent warming is faster than 99.7% of any other given 100-year period in the last 2000 years.

Global Warming

Hidden Channels Beneath East Antarctica Could Cause Massive Melt

A glacier the size of California in East Antarctica is in danger of melting away, which could lead to an extreme thaw increases sea levels by about 11.5 feet (3.5 meters) worldwide if the glacier vanishes, a new study finds.

Researchers have found two seafloor channels underneath the floating ice shelf of Totten Glacier in East Antarctica. The channels may let the warmest waters near the glacier to enter beneath the floating ice shelf, causing the rapid thinning of the ice shelf observed to date, the scientists said.

As the ice shelf thins, the point where the glacier starts to float will retreat, raising the sea level, and exposing more ice to the ocean.

The East Antarctic Ice Sheet is the largest body of ice in the world. “t’s larger than West Antarctica, it’s larger than Greenland. And within the East Antarctic Ice Sheet, Totten Glacier is the most rapidly thinning glacier. Its vulnerability to deep warm water, that we identify, is the most likely explanation to for its [thinning] behaviour.

Researchers of earlier studies have found deep, warm water in the ocean surrounding the glacier, but this is the first evidence that it could compromise the ice shelf itself.

Totten Glacier’s ice shelf is thinning by about 33 feet (10 m) a year, likely because warm water is melting it from underneath, the researchers said. And if the ice flowing through the glacier melts, it will be the equivalent of the entire West Antarctic Ice Sheet melting, the researchers found.

Unless snowfall outpaces coastal melting, the loss of Totten Glacier to the ocean may soon be irreversible

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Global Warming

Warm ocean melting East Antarctica’s largest glacier

The largest glacier in East Antarctica, containing ice equivalent to a six-metre (20-foot) rise in global sea levels, is melting due to warm ocean water, Australian scientists said on Monday.

The 120-kilometre (74.4 mile) long Totten Glacier, which is more than 30 kilometres wide, had been thought to be in an area untouched by warmer currents. But a just-returned voyage to the frozen region found the waters around the glacier were warmer than expected and likely melting the ice from below. “We knew that the glacier was thinning from the satellite data, and we didn’t know why,” the voyage’s chief scientist Steve Rintoul told AFP.

He said that up until recently the East Antarctica ice sheet had been thought surrounded by cold waters and therefore very stable and unlikely to change much. But the voyage found that waters around the glacier were some 1.5 degrees Celsius warmer than other areas visited on the same trip during the southern hemisphere summer. “We made it to the front of the glacier and we measured temperatures that were warm enough to drive significant melt,” Rintoul said. “And so the fact that warm water can reach this glacier is a sign that East Antarctica is potentially more vulnerable to changes in the ocean driven by climate change than we used to think.”

Previous expeditions had been unable to get close to the glacier due to heavy ice, but Rintoul said the weather had held for the Aurora Australis icebreaker and a team of scientists and technicians from the Australian Antarctic Division and other bodies.

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Wildlife

Emperor Penguins Shifting their Nesting Location Due to Climate Change

Emperor Penguins do not return to the same location every year to nest, as per findings of a new study carried out by group of researchers led by University of Minnesota. Contrary to earlier research projects which termed penguins as philopatric, emperor penguins are shifting their nesting place in the Antarctic Peninsula.

Over a period of three years, the research team found six instances when the emperor penguins didn’t return to the same place for breeding. The research team noticed the shifting patterns with satellite images. With high resolution satellite images, researchers across the world can easily keep track of the population of emperor penguins in the region and along the coastline.

Researchers from different universities across the world have been monitoring the population emperor penguins of Pointe Géologie colony. It was earlier suggested that the population of the flightless birds is facing threat due to climate change. In late 1970s, the population in the region declined by 50 percent within five years leading to fear among researchers that the population was declining fast.

The current study presents a contrary viewpoint and suggests that the population might be shifting between different colonies in the region. Penguins are smart enough to decide a different place each year, most probably, depending on the weather conditions.

The ice sheet in the Antarctic Peninsula is melting and researchers across the world have voiced their concerns on the climate change and its impact on then native species.

Emperor penguins nest

Wildlife

New ‘Penguin Flu’ Found in Antarctica

A new version of bird flu unlike any other seen on Earth has been discovered in Antarctica, researchers have announced.

However, the flu’s gene segments show no sign that the virus is particularly deadly, nor is it adapted to transmit to mammals. An attempt to infect ferrets (an animal commonly used in flu studies) with the disease failed to get the ferrets sick.

The study does raise “a lot of unanswered questions,” study researcher Aeron Hurt of the World Health Organization’s centre for flu research in Melbourne, Australia, said in a statement. Mysteries include how often avian flu viruses are introduced to the isolated continent of Antarctica and how they persist year after year.

Previous studies of penguins in Antarctica had found that multiple species of the bird sometimes carry flu antibodies in their blood. Antibodies are proteins created by the immune system in response to an infection.

But no one had ever found the virus itself. Hurt and his colleagues swabbed the tracheas and cloacas (waste and reproductive orifices) of 301 Adélie penguins from Admiralty Bay and Rada Covadonga on the Antarctica Peninsula. The researchers were also able to take blood samples from 270 of the birds.

In eight cases, the swabs turned up an influenza virus. The team was successfully able to culture four of the viruses in the lab, and found that all were strains of H11N2, a version of avian flu.

Intriguingly, these H11N2 strains did not look like strains seen elsewhere on Earth. Because avian flu is spread by migratory birds, strains tend to cluster in two groups defined by bird migrations: North American strains and Eurasian strains. Very little is known about avian flu in the Southern Hemisphere. Of 19,784 publicly available bird flu genetic sequences, only 5.7 percent come from Africa, 1 percent come from Australia and Oceania, and 0.1 percent come from South America.

Four of the gene segments analyzed in the new penguin flu look most similar to North American avian influenzas from the 1960s to the 1980s, while other segments look closer to South American strains, the researchers report today (May 6) in the journal mBio. One gene sequence looks most similar to H3N8, a virus known to infect horses, dogs and seals as well as birds.

Judging by the rate of evolutionary change in the virus, Hurt and his colleagues estimate that the virus has been evolving on its own in Antarctica for between 49 and 80 years. Migratory birds that travel to and from Antarctica, such as skuas and giant petrels, may be responsible for carrying flu viruses to penguin populations, the researchers wrote in mBio. Marine mammals such as seals could spread the viruses, too. Another possibility, they wrote, is that avian flu circulates among penguins and other birds in the summer and becomes frozen in ice over the winter, only to reactivate during the summer thaw.

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