Scientists monitor huge iceberg that broke off from Antarctica

NBC News via Reuters: Scientists are monitoring an iceberg roughly six times the size of Manhattan -- one of the largest now in existence -- that broke off from an Antarctic glacier and is heading into the open ocean. NASA glaciologist Kelly Brunt said on Wednesday the iceberg covers about 255 square miles (660 square km) and is up to a third of a mile (500 meters) thick. Known as B31, the iceberg separated from Antarctica's Pine Island Glacier last November, Brunt added.

"It's one that's large enough that it warrants monitoring," Brunt said in a telephone interview, noting that U.S. government organizations including the National Ice Center keep an eye on dozens of icebergs at any given time.

The iceberg's present location is not in an area heavily navigated by ships. "There's not a lot of shipping traffic down there. We're not particularly concerned about shipping lanes. We know where all the big ones are," she said.

Scientists are especially interested in this iceberg not only because of its size but because it originated in an unexpected location, said Brunt. "It's like a large sheet cake floating through the Southern Ocean," she added.

The glacial crack that created the iceberg was first detected in 2011, according to Brunt, a scientist with NASA Goddard Space Flight Center and Morgan State University in Maryland. Pine Island Glacier has been closely studied over the past two decades because it has been thinning and draining rapidly and may be an important contributor to sea level rise, scientists say.....

A November 2013 NASA image of the Pine Island Glacier

New research puts conventional theories about Titanic disaster on ice

A press release from the University of Sheffield: Academics at the University of Sheffield have dispelled a long-held theory that the Titanic was unlucky for sailing in a year with an exceptional number of icebergs and say the risk of icebergs is actually higher now.

Previously it had been suggested that the seas which sank the famous cruise ship – which set off on its maiden voyage 102 years ago today (Thursday 10 April 2014) – had an exceptional number of icebergs caused by lunar or solar effects. But academics at the University have shown the ship wasn’t as unlucky as previously thought.

Using data on iceberg locations dating back to 1913 – recorded to help prevent a repeat of the Titanic – they have shown that 1912 was a significant ice year but not extreme.

Professor Grant Bigg who led the research, said: “We have seen that 1912 was a year of raised iceberg hazard, but not exceptionally so in the long term. 1909 recorded a slightly higher number of icebergs and more recently the risk has been much greater – between 1991 and 2000 eight of the ten years recorded more than 700 icebergs and five exceeded the 1912 total.”

He added: “As use of the Arctic, in particular, increases in the future with the declining sea-ice the ice hazard will increase in water not previously used for shipping. As polar ice sheets are increasingly losing mass as well, the iceberg risk is likely to increase in the future, rather than decline.”

The iceberg which sank the Titanic was spotted just before midnight on 14 April 1912 500m away. Despite quick action to slow the ship it wasn’t enough and the ship sank in just two and a half hours. The disaster saw 1,517 people perish and only 700 survive....

Greenland's fastest glacier reaches record speeds

Science Daily: Jakobshavn Isbræ (Jakobshavn Glacier) is moving ice from the Greenland ice sheet into the ocean at a speed that appears to be the fastest ever recorded. Researchers from the University of Washington and the German Space Agency (DLR) measured the dramatic speeds of the fast-flowing glacier in 2012 and 2013.

The results are published today in The C
ryosphere, an open access journal of the European Geosciences Union (EGU). "We are now seeing summer speeds more than 4 times what they were in the 1990s on a glacier which at that time was believed to be one of the fastest, if not the fastest, glacier in Greenland," says Ian Joughin, a researcher at the Polar Science Center, University of Washington and lead-author of the study.

In the summer of 2012 the glacier reached a record speed of more than 17 kilometres per year, or over 46 metres per day. These flow rates are unprecedented: they appear to be the fastest ever recorded for any glacier or ice stream in Greenland or Antarctica, the researchers say.

They note that summer speeds are temporary, with the glacier flowing more slowly over the winter months. But they add that even the annually averaged speedup over the past couple of years is nearly 3 times what it was in the 1990s.

This speedup of Jakobshavn Isbræ means that the glacier is adding more and more ice to the ocean, contributing to sea-level rise. "We know that from 2000 to 2010 this glacier alone increased sea level by about 1 mm. With the additional speed it likely will contribute a bit more than this over the next decade," explains Joughin.

Jakobshavn Isbræ, which is widely believed to be the glacier that produced the large iceberg that sank the Titanic in 1912, drains the Greenland ice sheet into a deep ocean fjord on the coast of the island. At its calving front, where the glacier effectively ends as it breaks off into icebergs, some of the ice melts while the rest is pushed out, floating into the ocean. Both of these processes contribute about the same amount to sea-level rise from Greenland....

NASA false-color image of the Jakobshavn Glacier

New study indicates need for continuous satellite monitoring of ice sheets to better predict sea-level rise

University of Bristol press release: The length of the satellite record for the Greenland and Antarctic ice sheets is currently too short to tell if the recently reported speed-up of ice loss will be sustained in the future or if it results from natural processes, according to a new study led by Dr Bert Wouters from the University of Bristol.

The findings, published in Nature Geoscience, underscore the need for continuous satellite monitoring of the ice sheets to better identify and predict melting and the corresponding sea-level rise.

The ice sheets covering Antarctica and Greenland contain about 99.5 per cent of the Earth's glacier ice which would raise global sea level by some 63m if it were to melt completely.  The ice sheets are the largest potential source of future sea level rise – and they also possess the largest uncertainty over their future behaviour.  They present some unique challenges for predicting their future response using numerical modelling and, as a consequence, alternative approaches have been explored.  One common approach is to extrapolate observed changes to estimate their contribution to sea level in the future.

Since 2002, the satellites of the Gravity Recovery and Climate Experiment (GRACE) detect tiny variations in Earth’s gravity field resulting from changes in mass distribution, including movement of ice into the oceans. Using these  changes in gravity, the state of the ice sheets can be monitored at monthly intervals.

Dr Bert Wouters, currently a visiting researcher at the University of Colorado, said: "In the course of the mission, it has become apparent that ice sheets are losing substantial amounts of ice – about 300 billion tonnes each year – and that the rate at which these losses occurs is increasing.  Compared to the first few years of the GRACE mission, the ice sheets' contribution to sea level rise has almost doubled in recent years.”

Yet, there is no consensus among scientists about the cause of this recent increase in ice sheet mass loss observed by satellites.  Beside anthropogenic warming, ice sheets are affected by many natural processes, such as multi-year fluctuations in the atmosphere (for example, shifting pressure systems in the North Atlantic, or El Niño and La Niña events) and slow changes in ocean currents....

An iceberg off the coast of Tasilaq, Greenland, shot by Christine Zenino, Wikimedia Commons via Flickr, under the Creative Commons Attribution 2.0 Generic license

Greenland glacier loses ice island twice the size of Manhattan

UDaily at the University of Delaware: An ice island twice the size of Manhattan has broken off from Greenland’s Petermann Glacier, according to researchers at the University of Delaware and the Canadian Ice Service. The Petermann Glacier is one of the two largest glaciers left in Greenland connecting the great Greenland ice sheet with the ocean via a floating ice shelf.

Andreas Muenchow, associate professor of physical ocean science and engineering in UD’s College of Earth, Ocean, and Environment, reports the calving on July 16, 2012, in his “Icy Seas” blog. Muenchow credits Trudy Wohleben of the Canadian Ice Service for first noticing the fracture.

The discovery was confirmed by reprocessing data taken by MODIS, the Moderate Resolution Imaging Spectroradiometer aboard NASA’s Terra and Aqua satellites. At 46 square miles (120 square km), this latest ice island is about half the size of the mega-calving that occurred from the same glacier two years ago. The 2010 chunk, also reported by Muenchow, was four times the size of Manhattan.

“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,” Muenchow says. “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....

A big ice island calves from the Petermann Glacier in 2010, shot by NASA

Melting icebergs fertilize ocean

Janet Raloff in Science News: Efforts to remove climate-warming carbon dioxide from Earth’s atmosphere appear to be getting a helping hand from a surprising source: the iron in meltwater from Antarctic icebergs.

Icebergs calving off of Antarctica are shedding substantial iron — the equivalent of a growth-boosting vitamin — into waters starved of the mineral, a new set of studies demonstrates. This iron is fertilizing the growth of microscopic plants and algae, transforming the waters adjacent to ice floes into teeming communities of everything from tiny shrimplike krill to fish, birds and sometimes mammals.

To grow, these plants and animals use carbon drawn into the water from carbon dioxide in the atmosphere. Some share of this carbon will eventually be excreted as wastes that fall to the ocean floor, essentially removing it as a near-term climate risk.

“Icebergs should be considered by climate modelers, because the more icebergs that develop [from the breakup of glaciers], the more carbon dioxide you’ll draw out of the atmosphere,” says Ken Smith of the Monterey Bay Aquarium Research Institute in Moss Landing, Calif.

Smith and colleagues first fingered icebergs as hotspots of biological and chemical activity in a 2007 study published in Science. New data from Antarctic cruises in 2008 and 2009 by Smith and other scientists from nine research institutions now appear as 20 papers in the June Deep Sea Research Part II…

An iceberg off the Antarctic coast, shot by Jerzy Strzelecki, Wikimedia Commons, under the Creative Commons Attribution 3.0 Unported license

Antarctic icebergs play a previously unknown role in global carbon cycle, climate

Terra Daily: In a finding that has global implications for climate research, scientists have discovered that when icebergs cool and dilute the seas through which they pass for days, they also raise chlorophyll levels in the water that may in turn increase carbon dioxide absorption in the Southern Ocean.

…The research indicates that "iceberg transport and melting have a role in the distribution of phytoplankton in the Weddell Sea," which was previously unsuspected, said John J. Helly, director of the Laboratory for Environmental and Earth Sciences with the San Diego Supercomputer Center at the University of California, San Diego and Scripps Institution of Oceanography. Helly was the lead author of the paper, "Cooling, Dilution and Mixing of Ocean Water by Free-drifting Icebergs in the Weddell Sea," which was first published in the journal Deep-Sea Research Part II.

The results indicate that icebergs are especially likely to influence phytoplankton dynamics in an area known as "Iceberg Alley," east of the Antarctic Peninsula, the portion of the continent that extends northwards toward Chile.

The latest findings add a new dimension to previous research by the same team that altered the perception of icebergs as large, familiar, but passive, elements of the Antarctic seascape. The team previously showed that icebergs act, in effect, as ocean "oases" of nutrients for aquatic life and sea birds.

The teams's research indicates that ordinary icebergs are likely to become more prevalent in the Southern Ocean, particularly as the Antarctic Peninsula continues a well-documented warming trend and ice shelves disintegrate. Research also shows that these ordinary icebergs are important features of not only marine ecosystems, but even of global carbon cycling.

"These new findings amplify the team's previous discoveries about icebergs and confirm that icebergs contribute yet another, previously unsuspected, dimension of physical and biological complexity to polar ecosystems," said Roberta L. Marinelli, director of the NSF's Antarctic Organisms and Ecosystems Program...

An iceberg in the Weddell Sea, shot by the incomparable Frank Hurley during Sir Ernest Shackleton's epic 1916 Antarctic voyage

Giant icebergs head to watery end at island graveyard

Jonathan Amos in the BBC: The huge tabular blocks of ice that frequently break off Antarctica get swept towards the Atlantic and then ground on the shallow continental shelf that surrounds the 170km-long island. As they crumble and melt, they dump billions of tonnes of freshwater into the local marine environment.

UK scientists say the giants have quite dramatic impacts, even altering the food webs for South Georgia's animals. … "The scale of some these icebergs is something else," said oceanographer Dr Mark Brandon from the Open University.

"The iceberg known as A-38 had a mass of 300 gigatonnes. It broke up into two fragments, but it also shattered into lots of smaller bergs. Each smaller berg was still fairly big and each dumped lots of freshwater into the system."

…With a group of colleagues he planted scientific moorings off South Georgia in several hundred metres of water. The moorings held sensors to monitor the physical properties of the water, including temperature, salinity and water velocity. The presence of plankton was also measured. The moorings were in prime position to capture what happened when the mega-berg A-38 turned up in 2004.

It is one of many tabular blocks, such as B-10A and A-22B, which have been caught at South Georgia, which lies downstream of the Antarctic Peninsula in currents known as the Weddell-Scotia Confluence…

From NASA, the split of the A38-B iceberg is recorded in this series of images. The iceberg was originally part of the massive A-38 iceberg, which broke from the Ronne Ice Shelf in Antarctica. Another section of the A-38 iceberg, A-39D, was covered in melt water ponds as it drifted past South Georgia Island in late January 2004—the height of the summer in the Southern Hemisphere.

Giant iceberg drifting toward Canada could threaten ships, oil platforms

Randy Boswell in the Montreal Gazette: The Canadian government's top ice experts have begun planning how to deal with a massive iceberg that broke off a Greenland glacier last week and is expected to drift south over the next two years into East Coast shipping lanes and toward offshore oil platforms. NASA, the European Space Agency and a host of academic institutions are already helping Canadian officials monitor and analyze the mammoth object, the biggest free-floating mass of ice in the Arctic Ocean in 50 years.

Environment Canada's Trudy Wohlleben, the Canadian Ice Service forecaster who first spotted last Thursday's birth of Petermann Ice Island 2010, said Tuesday that federal scientists plan to parachute beacons onto the 250-square-kilometre monolith next month to help track its movements along Ellesmere and Baffin islands and, eventually, down the coasts of Labrador and Newfoundland.

Icebergs calved from Greenland's glaciers and floating ice shelves typically follow that Canadian route south, as did the huge one that struck and sank the Titanic in 1912. Wohlleben said the Canadian Ice Service does have "a precedent" to help shape its response to the latest threat — a 29-square-kilometre iceberg that broke away from the Petermann Glacier in 2008 and required constant monitoring until the end of last summer. "But this one is about 10 times larger," she told Postmedia News on Tuesday. "It's something we'll be watching closely."

The ESA released satellite images of the ice island on Monday and the agency's Italy-based spokesman Robert Meisner said Tuesday that Canadian officials will have "regular and full access to Envisat Radar data for sea ice charting activity."….

European Space Agency satellite image of huge iceberg calving from the Petermann Glacier in Greenland

Greenland ice island prompts global warming debate

Voice of America: Heat waves, droughts and floods have been wreaking havoc across the globe in recent weeks, and now scientists say a 250 square kilometer island of ice has broken off from a glacier in Greenland. Some are blaming this huge chunk of ice on global warming, while others say such breaks in the Arctic ice are a normal occurrence.

The ice island that broke off from Greenland's Petermann glacier is more than four times the size of the New York City's Manhattan Island. Jim Scianna of the U.S. National Ice Center, tells VOA breakage like this is fairly routine in the Arctic. "There's about 10-40,000 of them that occur during the year in the Arctic region. What's unusual about this one is the size," he said.

And the size of the massive iceberg has some people worried, like Greenpeace activist Melanie Duchin. "I think this is more evidence to add to the growing body of knowledge that shows that climate change is happening," he said.

Scientists say they cannot confirm whether the rip in the ice was caused by global warming because of a lack of information. They only started keeping records on the sea water around the glacier in 2003.

And ocean science professor Andreas Muenchow says years of data on the glacier itself show that after this month's event, the mass of ice is still, on average, discharging about the same amount of water it usually does - some 600 million cubic meters a year, or about 220,000 Olympic-sized swimming pools. "Even a big piece like this over 50 years is not that significant. It's just the normal rate," he said.

Muenchow warns people not to jump to conclusions. "An event like this, this specific event, all flags go immediately up, 'Oh, let's explain this by global warming.' I cannot support that," he said….

A generic iceberg from overhead, shot by Jason Auch, Wikimedia Commons via Flickr, under the Creative Commons Attribution 2.0 Generic license

Greenland glacier spawns giant ice island

Katie Stallard in Sky News: An ice island with an area of 100 square miles (260 square km) has broken off from one of Greenland's two main glaciers in an event that is the biggest of its kind for nearly 50 years. A chunk of ice was predicted to come away from the Petermann Glacier - of the two largest remaining ones in Greenland - but never at this scale.

The 600ft (180m)-thick island, which broke off on Thursday, will enter a remote place called the Nares Strait, about 620 miles south of the North Pole between Greenland and Canada. Icebergs can make negotiating the waters around Greenland a very hazardous business, as Sky News discovered during a flight with the Greenland Ice Patrol.

They are the Arctic's fourth emergency service, covering a stretch of coastline 400km long, including the latest breakaway from the Petermann Glacier…...

A generic shot of a glacier in Greenland, shot by Mila Zinkova, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license