The Greening Arctic

Over the past three decades, temperatures have risen faster in the Arctic than anywhere else in the world. Consequently, the growing season has gotten longer in the far north, bringing major changes to plant communities in tundra and boreal (also known as taiga) ecosystems.

For decades, instruments on various NASA and NOAA satellites have continuously monitored vegetation from space. The Moderate Resolution Imaging Spectroradiometer (MODIS) and Advanced Very High Resolution Radiometer (AVHRR) instruments measure the intensity of visible and near-infrared light reflecting off plant leaves. Scientists use that information to calculate the Normalized Difference Vegetation Index (NDVI), an indicator of photosynthetic activity or “greenness” of the landscape.

The maps above show NDVI trends between July 1982 and December 2011 for the northern portions of North America and Eurasia. Shades of green depict areas where plant productivity and abundance increased; shades of brown show where photosynthetic activity declined. There was no trend in areas that are white; areas that are gray were not included in the trend analysis. An international team of university and NASA scientists published an analysis of the NDVI data in Nature Climate Change in March 2013.
The maps show a ring of greening in the treeless tundra ecosystems of the circumpolar Arctic—the northernmost parts of Canada, Russia, and Scandinavia. Tall shrubs and trees have started to grow in areas that were previously dominated by tundra grasses. The researchers concluded that plant growth had increased by 7 to 10 percent overall.

However, boreal forests to south of the tundra, particularly those in North America, show a different response to warming. Many boreal forests greened, but the trend was not as strong as it was for the circumpolar Arctic. In North America, some boreal forests actually experienced “browning” (less photosynthetic activity) over the study period. Droughts, forest fire activity, animal and insect behavior, industrial pollution, and a number of other factors may have contributed to the browning.

“Satellite data identify areas in the boreal zone that are warmer and drier and other areas that are warmer and wetter,” explained co-author Ramakrishna Nemani of NASA’s Ames Research Center. “Only the warmer and wetter areas support more growth.”

“We found more plant growth in the boreal zone from 1982 to 1992 than from 1992 to 2011, because water limitations were encountered in the later two decades of our study,” said co-author Sangram Ganguly of the Bay Area Environmental Research Institute and NASA Ames.

• References

• Boston University Climate and Vegetation Research Group Temperature and Vegetation Seasonality Diminishment over Northern Lands. Accessed March 13, 2013.
• Boston University (2013, March 10) Amplified greenhouse effect shaping North into South (pdf). Accessed March 13, 2013.
• NASA (2013, March 10) Amplified greenhouse effect shaping North into South. Accessed March 13, 2013.
• Xu, L. et al (2013, March 10) Temperature and vegetation seasonality diminishment over northern lands. Nature Climate Change, 3(3). Accessed March 13, 2013.

1. Related Reading

2. Earth Observatory (2002, August 20) The Migrating Boreal Forest. Accessed March 13, 2013.
Earth Observatory (2006, April 18) Forests on the Threshold. Accessed March 13, 2013.

NASA Earth Observatory image by Robert Simmon, using MODIS and AVHRR data from the Boston University’s Climate and Vegetation Research Group. Caption by Adam Voiland with information from Kathryn Hansen.

Instrument: 

Terra - MODIS

What Lies Beneath: NASA Antarctic Sub Goes Subglacial

 

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.php?release=2013-077&cid=release_2013-077

A mini-submarine designed and funded by NASA played a key role in a recent international expedition to explore a remote subglacial lake beneath the frozen Antarctic ice sheet. Text: When researcher Alberto Behar from NASA's Jet Propulsion Laboratory in Pasadena, Calif., joined an international Antarctic expedition last month on a trek to investigate a subglacial lake, he brought with him a unique instrument designed and funded by NASA to help the researchers study one of the last unexplored aquatic environments on Earth.

Called the Micro-Submersible Lake Exploration Device, the instrument was a small robotic sub about the size and shape of a baseball bat. Designed to expand the range of extreme environments accessible by humans while minimally disturbing the environment, the sub was equipped with hydrological chemical sensors and a high-resolution imaging system. The instruments and cameras characterize the geology, hydrology and chemical characteristics of the sub's surroundings. Behar supervised a team of students from Arizona State University, Tempe, in designing, developing, testing and operating the first-of-its-kind sub.

"This is the first instrument ever to explore a subglacial lake outside of a borehole," Behar said. "It's able to take us places that are inaccessible by any other instruments in existence."

The sub was deployed by the U.S. team of the international Whillans Ice Stream Subglacial Access Research Drilling (WISSARD) project. The project's objective was to access subglacial Lake Whillans, located more than 2,000 feet (610 meters) below sea level, deep within West Antarctica's Ross Ice Shelf, nearly 700 miles (about 1,125 kilometers) from the U.S. McMurdo Station. The 20-square-mile (50-square-kilometer) lake is totally devoid of sunlight and has a temperature of 31 degrees Fahrenheit (minus 0.5 degrees Celsius). It is part of a vast Antarctic subglacial aquatic system that covers an area about the size of the continental United States.

The WISSARD team included researchers from eight U.S. universities and two collaborating international institutions. They used specialized tools to get clean samples of subglacial lake water and sediments, survey the lake floor with video and characterize the biological, chemical and physical properties of the lake and its surroundings. Their research is designed to gain insights into subglacial biology, climate history and modern ice sheet behavior.

The instrument consists of a "mothership" connected to a deployment device that houses the submarine. The sub is designed to operate at depths of up to three-quarters of a mile (1.2 kilometers) and within a range of 0.6 miles (1 kilometer) from the bottom of the borehole that was drilled through the ice to reach the lake. It transmits real-time high-resolution imagery, salinity, temperature and depth measurements to the surface via fiber-optic cables.

In a race against time and the elements to access the lake before the end of the current Antarctic field season, the WISSARD team spent three days in January drilling a 2,600-foot-deep (800-meters), 20-inch-wide (50-centimeters) borehole into the lake, which they reached on Jan. 28.

Like Alice down the rabbit hole, the sub was then sent down the borehole, where it was initially used to guide drilling operations. When the instrument finally reached the lake, the team used its imagery to survey the lake floor. The data enabled the team to verify that the rest of the project's instruments could be safely deployed into the lake. The WISSARD team was then able to proceed with its next phase: collecting lake water samples to search for microbial life.

And that search has apparently paid off. Earlier this month, the team reported that the lake water did indeed contain living bacteria, a discovery that might hold important implications for the search for life elsewhere in the universe.

To learn more about the expedition, watch this short video narrated by Behar: http://www.jpl.nasa.gov/video/?id=1201 .

Core funding for WISSARD and the Micro-Submersible Lake Exploration Device was provided by the National Science Foundation-Office of Polar Programs. The sub was funded by NASA's Cryospheric Sciences and Astrobiology programs. Additional funds for WISSARD instrument development were provided by the National Oceanic and Atmospheric Administration and the Gordon and Betty Moore Foundation.

For more on WISSARD, visit: http://www.wissard.org . For more on Behar's previous robotic Antarctic research, visit: http://www.nasa.gov/topics/earth/features/antarctic-shrimp.html .

Alan Buis 818-354-0474
Jet Propulsion Laboratory, Pasadena, Calif.
alan.buis@jpl.nasa.gov

- end -

Ice Sheet Loss at Both Poles Increasing, Study Finds

The midnight sun casts a golden glow on an iceberg and its reflection in Disko Bay, Greenland. Much of Greenland's annual ice mass loss occurs through calving of icebergs such as this. Image credit: Ian Joughin, University of Washington › Full image and caption

PASADENA, Calif. - An international team of experts supported by NASA and the European Space Agency (ESA) has combined data from multiple satellites and aircraft to produce the most comprehensive and accurate assessment to date of ice sheet losses in Greenland and Antarctica and their contributions to sea level rise.

In a landmark study published Thursday in the journal Science, 47 researchers from 26 laboratories report the combined rate of melting for the ice sheets covering Greenland and Antarctica has increased during the last 20 years. Together, these ice sheets are losing more than three times as much ice each year (equivalent to sea level rise of 0.04 inches or 0.95 millimeters) as they were in the 1990s (equivalent to 0.01 inches or 0.27 millimeters). About two-thirds of the loss is coming from Greenland, with the rest from Antarctica.

Monthly changes in Antarctic ice mass, in gigatones, as measured by NASA's Gravity Recovery and Climate Experiment (GRACE) satellites from 2003 to 2011. Image credit: NASA-JPL/Caltech; NASA GSFC; CU-Boulder; Technical University of Munich; Technical University of Denmark; Delft University of Technology, Aerospace Engineering, Netherlands; Durham University, UK; Leeds University, UK

This rate of ice sheet losses falls within the range reported in 2007 by the Intergovernmental Panel on Climate Change (IPCC). The spread of estimates in the 2007 IPCC report was so broad, however, it was not clear whether Antarctica was growing or shrinking. The new estimates, which are more than twice as accurate because of the inclusion of more satellite data, confirm both Antarctica and Greenland are losing ice. Combined, melting of these ice sheets contributed 0.44 inches (11.1 millimeters) to global sea levels since 1992. This accounts for one-fifth of all sea level rise over the 20-year survey period. The remainder is caused by the thermal expansion of the warming ocean, melting of mountain glaciers and small Arctic ice caps, and groundwater mining.

The study was produced by an international collaboration -- the Ice Sheet Mass Balance Inter-comparison Exercise (IMBIE) -- that combined observations from 10 satellite missions to develop the first consistent measurement of polar ice sheet changes. The researchers reconciled differences among dozens of earlier ice sheet studies by carefully matching observation periods and survey areas. They also combined measurements collected by different types of satellite sensors, such as ESA's radar missions; NASA's Ice, Cloud and land Elevation Satellite (ICESat); and the NASA/German Aerospace Center's Gravity Recovery and Climate Experiment (GRACE).

"What is unique about this effort is that it brought together the key scientists and all of the different methods to estimate ice loss," said Tom Wagner, NASA's cryosphere program manager in Washington. "It's a major challenge they undertook, involving cutting-edge, difficult research to produce the most rigorous and detailed estimates of ice loss from Greenland and Antarctica to date. The results of this study will be invaluable in informing the IPCC as it completes the writing of its Fifth Assessment Report over the next year."

Professor Andrew Shepherd of the University of Leeds in the United Kingdom coordinated the study, along with research scientist Erik Ivins of NASA's Jet Propulsion Laboratory in Pasadena, Calif. Shepherd said the venture's success is because of the cooperation of the international scientific community and the precision of various satellite sensors from multiple space agencies.

Over the course of several years, turbulent water overflow from a large melt lake carved this 60-foot-deep (18.3 meter-deep) canyon Image credit: Ian Joughin, University of Washington

"Without these efforts, we would not be in a position to tell people with confidence how Earth's ice sheets have changed, and to end the uncertainty that has existed for many years," Shepherd said.

The study found variations in the pace of ice sheet change in Antarctica and Greenland.

"Both ice sheets appear to be losing more ice now than 20 years ago, but the pace of ice loss from Greenland is extraordinary, with nearly a five-fold increase since the mid-1990s," Ivins said. "In contrast, the overall loss of ice in Antarctica has remained fairly constant, with the data suggesting a 50-percent increase in Antarctic ice loss during the last decade."

For more on ICESat, visit: http://icesat.gsfc.nasa.gov . For more on GRACE, visit: http://www.csr.utexas.edu/grace .

The California Institute of Technology in Pasadena manages JPL for NASA.

Alan Buis 818-354-0474
Jet Propulsion Laboratory, Pasadena, Calif.
alan.buis@jpl.nasa.gov

Steve Cole 202-358-0918
NASA Headquarters, Washington
Stephen.e.cole@nasa.gov

Esther Harward 44 113 343 4196
University of Leeds, United Kingdom
e.harward@leeds.ac.uk

A Block of Thwaites

Since October 2009, NASA and its scientific partners have made yearly airborne surveys of Antarctica and Greenland—with occasional trips to Alaska and the Arctic Ocean. The goal is to study changes in the structure and motion of the ice at both poles, and to fill in the gap in data between the ICESat satellite mission (which officially ended in 2010) and the launch of ICESat II around 2016. The plane-based project is called Operation Icebridge.
In October and November 2012, the Icebridge team returned to Antarctica for a fourth southern springtime, flying NASA’s DC-8 research plane on roundtrip surveys from Punta Arenas, Chile, to the edges of Antartica and back—flights that can last 11–12 hours.
In 2012, the research team put extra emphasis on gathering imagery and data from Thwaites Glacier and Pine Island Glacier; from the ice streams feeding the Ronne and Filchner ice shelves; and the sea ice in the Weddell and Bellingshausen seas, as well as the ice streams flowing into them. Most of the flights covered areas in West Antarctica, where melting and ice motion has been accelerating in recent years.
The photograph above shows an edge of the Thwaites Ice Shelf and was taken by Jim Yungel, program manager for the Airborne Topographic Mapper, a laser altimeter carried by the DC-8. The blue areas visible on the shelf edge are areas of denser, compressed ice. Over time, the weight of polar glaciers and ice sheets compresses ice and squeezes out the gases and air.
Thwaites Glacier is rapidly changing, and the Icebridge team has surveyed it multiple times. In research published in 2011, scientists from Columbia University revealed that the glacier is pinned to an underwater ridge just offshore in Pine Island Bay, and that ridge helps pile up the ice and slow its advance into the sea. But the connection is weakening, and researchers project that Thwaites will come unpinned and start advancing much faster within the next 20 years or so.
Read mission updates and other background about Operation Icebridge on their blog and their news page. You can also view a short video here.

1. Further Reading

2. NASA Earth Observatory (2011, November 2) IceBridge: Building a Record of Earth’s Changing Ice, One Flight at a Time.
3. Tinto, K. J. and R. E. Bell (2011) Progressive unpinning of Thwaites Glacier from newly identified offshore ridge: Constraints from aerogravity. Geophysical Research Letters, Vol. 38, L20503.

NASA photograph by Jim Yungel. Caption by Mike Carlowicz

Instrument: 

Photograph - NASA

Antarctica: Tower View

On top of the highest tower in Antarctica looking back at Concordia base that is 3200 metres above sea level.

Alexander Kumar and Sebastian Aubin had to climb 40 metres up the tower in –60°C to take this picture.

At these temperatures and at such altitude Alex and Seb work and live in constant hypoxia - lack of oxygen to the brain. Even simple actions can become complicated in these conditions.

During the winter period no sunlight reaches Concordia base for four months, the 13 crewmembers are on their own.

ESA is studying the effects of isolation and living with limited oxygen in preparation for future space mission.

Credits: ESA/IPEV/PNRA - A. Kumar

Antarctic Sea Ice Reaches New Maximum Extent

Two weeks after a new record was set in the Arctic Ocean for the least amount of sea ice coverage in the satellite record, the ice surrounding Antarctica reached its annual winter maximum—and set a record for a new high. Sea ice extended over 19.44 million square kilometers (7.51 million square miles) in 2012, according to the National Snow and Ice Data Center (NSIDC). The previous record of 19.39 million kilometers (7.49 million square miles) was set in 2006.
The map above shows sea ice extent around Antarctica on September 26, 2012, when ice covered more of the Southern Ocean than at any other time in the satellite record. The map is based on an NSIDC analysis of data from the Special Sensor Microwave/Imagers flown in the Defense Meteorological Satellite Program. Land is dark gray, and ice shelves—which are attached to land-based glaciers but floating on the ocean—are light gray. The yellow outline shows the median sea ice extent in September from 1979 to 2000. Sea ice extent is defined as the total area in which the ice concentration is at least 15 percent.
The graph of NSIDC data shows the maximum extent for each September since 1979 in millions of square kilometers. There is a lot of variability from year to year, though the overall trend shows growth of about 0.9 percent per decade.
According to a recent study by sea ice scientists Claire Parkinson and Donald Cavalieri of NASA’s Goddard Space Flight Center, Antarctic sea ice increased by roughly 17,100 square kilometers per year from 1979 to 2010. Much of the increase, they note, occurred in the Ross Sea, with smaller increases in Weddell Sea and Indian Ocean. At the same time, the Bellinghausen and Amundsen Seas have lost ice. “The strong pattern of decreasing ice coverage in the Bellingshausen/Amundsen Seas region and increasing ice coverage in the Ross Sea region is suggestive of changes in atmospheric circulation,” they noted.
“The year 2012 continues a long-term contrast between the two hemispheres, with decreasing sea ice coverage in the Arctic and increasing sea ice coverage in the Antarctic,” Parkinson added. “Both hemispheres have considerable inter-annual variability, so that in either hemisphere, next year could have either more or less sea ice than this year. Still, the long-term trends are clear, but not equal: the magnitude of the ice losses in the Arctic considerably exceed the magnitude of the ice gains in the Antarctic.”
On their Arctic Sea Ice News and Analysis blog, scientists from the University of Colorado wrote: “Comparing winter and summer sea ice trends for the two poles is problematic since different processes are in effect. During summer, surface melt and ice-albedo feedbacks are in effect; winter processes include snowfall on the sea ice, and wind. Small changes in winter extent may be a more mixed signal than the loss of summer sea ice extent. An expansion of winter Antarctic ice could be due to cooling, winds, or snowfall, whereas Arctic summer sea ice decline is more closely linked to decadal climate warming.”

1. References

2. Parkinson, C.L., and D.J. Cavalieri (2012, August 15) Antarctic sea ice variability and trends, 1979-2010. The Cryosphere, Volume 6, pages 871-880.
3. NASA Earth Observatory (2009, April 20) Sea Ice.
4. NASA Earth Observatory (n.d.) World of Change: Antarctic Sea Ice.
5. NASA (2009, September 1) What's Holding Back Antarctic Sea Ice from Melting. Accessed October 10, 2012.
6. National Snow and Ice Data Center (2012, October 2) Poles Apart: A record-breaking summer and winter. Accessed October 10, 2012.
7. The New York Times (2012, October 3) Running the Numbers on Antarctic Sea Ice.

NASA Earth Observatory images by Jesse Allen, using DMPS SSMIS ice concentration data provided courtesy of the National Snow and Ice Data Center (NSIDC). Caption by Michael Carlowicz

Instrument: 

DMSP - SSMIS - NASA

As ice melts Britain calls for a moratorium on arctic drilling

NASA handout image shows how satellite data reveals how the new record low Arctic sea ice extent, compares to the average minimum extent over the past 30 years (in yellow). Sea ice extent maps are derived from data captured by the Scanning Multichannel Microwave Radiometer aboard NASA's Nimbus-7 satellite and the Special Sensor Microwave Imager on multiple satellites from the Defense Meteorological Satellite Program. Image by: NASA / Handout

British Lawmakers are calling for a moratorium on offshore drilling in the arctic, as US scientists record the ice shrinking to its lowest level on record.

The Environmental Audit Committee of Britain's House of Commons urged action to halt oil and gas drilling in the Arctic until new safeguards -including vastly increased financial guarantees and universal standards on disaster response - are put in place.

Legislators on the panel also called for an internationally recognised nature sanctuary to be created to protect at least part of the Arctic from energy exploration.

Caroline Lucas, a member of the committee and the only Green Party lawmaker at Britain's Parliament, said the panel's findings came as "the race to carve up the Arctic is accelerating faster than our regulatory or technical capacity to manage it."

"The Arctic oil rush is bringing unprecedented risks to the area, and it's now clear that the consequences of any potential oil spill would be catastrophic," she said.

Recommendations by the panel are not binding on Britain's government, and in response the country's foreign ministry said only that it would consider the proposals.

Experts warned the panel that any blowout in the Arctic at the end of the summer drilling season could be disastrous, as the returning winter ice would likely severely hamper the response.

"We heard compelling evidence that if a blow-out occurred just before the dark Arctic winter returned it may not be possible to cap it until the following summer - potentially leaving oil spewing out under the ice for six months or more with devastating consequences for wildlife," said lawmaker Joan Walley, chairwoman of the committee.

In a report, legislators said that the fact Arctic drilling locations are remote means resources to manage accidents are likely to be difficult to access or unavailable. Because shorelines are sparsely populated, it would also be more difficult to detect evidence of a spill.

"The infrastructure to mount a big clean-up operation is simply not in place and conventional oil spill response techniques have not been proven to work in such severe conditions," Walley said.

Legislators called on Britain to lobby the Arctic Council - an intergovernmental forum of the eight Arctic nations, including the United States and Canada - to craft a universal standard on disaster response.

The panel also suggested a "much higher, preferably unlimited, financial liability regime for oil and gas operations."

Britain's energy and climate change ministry said that, given the U.K.'s lack of "expertise or experience of Arctic issues," nations in the region should take the lead.

Charles Emmerson, an energy expert at the London-based Chatham House think tank, said it was "extremely unlikely" that nations competing over Arctic resources would agree to a single regulatory framework.

Richard Steiner, an Alaska-based marine conservation consultant who gave evidence to the committee via video link, urged the eight Arctic coastal nations and the U.N. to adopt the report's recommendations.

"It represents the first time a governmental body has really and honestly suggested what needs to happen to manage the Arctic responsibly," he said. "The U.K. Parliamentary body has proposed a realistic road-map for Arctic stewardship."

Environmental groups strongly oppose Arctic offshore drilling, claiming oil companies have not demonstrated the ability to clean up spilled crude in ice. Operating in one of the world's most hostile marine environments is a risk to its polar bears, walrus and endangered whales, the groups claim.

Shell has limited Arctic drilling off Alaska to preparation work this year after a safety system was damaged during testing.

However, Marvin Odum, head of Shell Oil Co., Royal Dutch Shell's U.S. subsidiary, insists it is optimistic about tapping into an estimated 26 billion barrels of recoverable oil and 130 trillion cubic feet (3.68 trillion cubic meters) of natural gas in U.S. Arctic waters.

In evidence to the British committee, Robert Blaauw, a senior Shell adviser on the Arctic, said energy demand over the coming decades made it necessary for companies to look to "unconventional resources" such as those in the Arctic.

The company said that it welcomed dialogue on Arctic energy exploration.

Ice at lowest level on record

Arctic sea ice has shrunk to its smallest surface area since record-keeping began, taking the world into “uncharted territory” as climate change intensifies, US scientists warned.

Satellite images show the ice cap had melted to 1.32 million square miles (3.4 million square kilometers) as of September 16, the predicted lowest point for the year.

That’s the smallest Arctic ice cover since record-keeping began in 1979, the National Snow and Ice Data Center said.

“We are now in uncharted territory,” the center’s director, Mark Serreze, 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,” he added.

Arctic sea ice expands and contracts seasonally, with the lowest extent usually occurring in September.

This year’s minimum followed a season already full of records for shrinking ice, with lowest ever extents recorded on August 26 and again on September 4.

And in the last two weeks, the ice cover melted by more than 200,000 square miles (518,000 square kilometers), quite a large margin for the end of the summer, the NSIDC said.

“The strong late season decline is indicative of how thin the ice cover is,” said NSIDC scientist Walt Meier.

“Ice has to be quite thin to continue melting away as the sun goes down and fall approaches.”

Scientists use Arctic sea ice extent as an indicator of what’s happening with the overall climate. Despite year-to-year fluctuations from natural weather variations, the ice cap has shown a clear trend towards shrinking over the last 30 years, the NSIDC center said.

“This year’s minimum will be nearly 50% lower than the 1979 to 2000 average,” the statement noted.

The Colorado-based center said the Arctic is shifting in composition. Whereas previously most of the ice stayed frozen through several summers, now much of it melts and refreezes each season.

“Twenty years from now in August you might be able to take a ship right across the Arctic Ocean,” once blocked year-round by ice, said NSIDC scientist Julienne Stroeve.

Climate models predict “ice free conditions” before 2050, she added, but said the decline appears to be happening faster than predicted.

The NSIDC warned that increased heat and moisture from the melting Arctic ice cover could have global climate implications.

“This will gradually affect climate in the areas where we live,” he said. “We have a less polar pole — and so there will be more variations and extremes.” Environmental activist group Greenpeace lamented the announcement.

“In just over 30 years we have altered the way our planet looks from space, and soon the North Pole may be completely ice free in summer,” Greenpeace chief Kumi Naidoo, said in a statement.

“I hope that future generations will mark this day as a turning point, when a new spirit of global cooperation emerged to tackle the huge challenges we face,” he added.

- Times Live

Arctic Sea Ice Drops below 2007 Record

On August 26, 2012, the extent of Arctic water covered by sea ice fell below 4.17 million square kilometers (1.61 million square miles), the record minimum set in 2007. Arctic sea ice stood at 4.10 million square kilometers (1.58 million square miles), the National Snow and Ice Data Center (NSIDC) and NASA reported on August 27.

This image was made from observations collected by the Special Sensor Microwave Imager/Sounder (SSMIS) on the satellites of the U.S. Defense Meteorological Satellite Program. Sea ice appears in shades of white and light blue, with white indicating the greatest concentrations of ice. Open ocean water is blue, and land is gray. The yellow outline shows the median minimum ice extent for 1979-2000—in other words, areas that were at least 15 percent ice-covered in at least half the years between 1979 and 2000—on August 26.
In April 2012, Arctic sea ice reached a near-average extent, but periods of intense ice loss in June and August 2012 helped push Arctic sea ice below the previous record from 2007. In 2007, high pressure over the Beaufort Sea and low pressure over northeastern Eurasia pulled in warm winds, which melted the ice and pushed it away from the Siberian and Alaskan coastlines. Although these pressure patterns also occurred in 2012, they were much less persistent. Nonetheless sea ice melt rates still reached up to 150,000 square kilometers (57,900 square miles) per day in 2012, more that twice the long-term rate.

By early July, Arctic sea ice melting was three weeks ahead of schedule, but then slowed somewhat. Ice loss rates picked up again in early August, “probably the highest in the record for that period,” according to NSIDC staff scientist Walt Meier. Because the old record has been passed in August 2012—and Arctic sea ice generally reaches its lowest annual extent in September—it is likely that the amount of ice cover may continue to shrink. NSIDC provides an overview of melt rates in its Arctic Sea Ice News and Analysis blog.
Arctic sea ice reached previous record lows in 2002, 2005, and 2007. (The 2007 record low was previously recorded as 4.13 million square kilometers, or 1.59 million square miles. Slightly different processing and quality-control procedures used by NASA Goddard Space Flight Center led to revised estimates of sea ice extent.) Over the past decade, sea ice extent in the Arctic has been well below the 1979–2000 average.

The loss of so much sea ice means that when ice reforms over the winter, it is “first-year ice,” which is much thinner than sea ice that has persisted over multiple years. Joey Comiso, senior research scientist at NASA Goddard Space Flight Center, explained that the loss of this multiyear ice contributed to record low ice extent in 2012. Another possible factor at work in the summer of 2012, Comiso suggested, may have been a strong summer cyclone, which broke up ice in the Central Arctic and dispersed it into warmer waters.
NSIDC director Mark Serreze differed with Comiso somewhat on the role of the storm. “The ice was already so thin it was ready to go,” said Serreze. “2012 likely would have set a new record without the storm.”

Once sea ice loss gets underway, it can become a self-reinforcing process. Because there is less light-colored ice to reflect the Sun’s energy back into space, more energy is absorbed by darker ocean water.
A new record for sea ice was not the only unusual event in the Arctic in the summer of 2012. July 2012 saw widespread melt on the Greenland Ice Sheet and the calving of a new iceberg from Greenland’s Petermann Glacier. By early August, rapid sea ice retreat left the Northwest Passage nearly open, although ice moved back into parts of the passage later in the month.

The new record low for sea ice in 2012 fits into a larger pattern of a changing Arctic. Regarding the rapid loss of Arctic sea ice, Serreze remarks, “What is perhaps most surprising is that we are no longer surprised.”

1. References

2. NSIDC. (2012, August 27) Arctic sea ice breaks lowest extent on record. Accessed August 27, 2012.
3. NSIDC. (2012, August 27) Arctic Sea Ice News and Analysis. Accessed August 27, 2012.
4. NSIDC. (2012, May 21) State of the Cryosphere: Sea Ice. Accessed August 27, 2012.

NASA Earth Observatory image by Jesse Allen, using data from the National Snow and Ice Data Center. Caption by Michon Scott.

Instrument: 

DMSP - SSM/I -  NASA

Arctic sea ice reaches record low, Nasa says

The melt season is expected to continue until the second half of September

The Arctic has lost more sea ice this year than at any time since satellite records began in 1979, Nasa says.

Scientists involved in the calculations say it is part of a fundamental change.

What is more, sea ice normally reaches its low point in September so it is thought likely that this year's melt will continue to grow.

Nasa says the extent of sea ice was 1.58m sq miles (410m sq km) compared with a previous low of 1.61m sq miles (4.17m sq km) on 18 September 2007.

The sea ice cap grows during the cold Arctic winters and shrinks when temperatures climb again, but over the last three decades, satellites have observed a 13% decline per decade in the summertime minimum.

The thickness of the sea ice is also declining, so overall the ice volume has fallen far - although estimates vary about the actual figure.

Joey Comiso, senior research scientist at Nasa's Goddard Space Flight Center, said this year's ice retreat was caused by previous warm years reducing the amount of perennial ice - which is more resistant to melting. It's created a self-reinforcing trend.

"Unlike 2007, temperatures were not unusually warm in the Arctic this summer. [But] we are losing the thick component of the ice cover," he said. "And if you lose [that], the ice in the summer becomes very vulnerable."
'Inevitable death'

Walt Meier, from the National Snow and Ice Data Center that collaborates in the measurements, said: "In the context of what's happened in the last several years and throughout the satellite record, it's an indication that the Arctic sea ice cover is fundamentally changing."

Professor Peter Wadhams, from Cambridge University, told BBC News: "A number of scientists who have actually been working with sea ice measurement had predicted some years ago that the retreat would accelerate and that the summer Arctic would become ice-free by 2015 or 2016.

"I was one of those scientists - and of course bore my share of ridicule for daring to make such an alarmist prediction."

But Prof Wadhams said the prediction was now coming true, and the ice had become so thin that it would inevitably disappear.

"Measurements from submarines have shown that it has lost at least 40% of its thickness since the 1980s, and if you consider the shrinkage as well it means that the summer ice volume is now only 30% of what it was in the 1980s," he added.

"This means an inevitable death for the ice cover, because the summer retreat is now accelerated by the fact that the huge areas of open water already generated allow storms to generate big waves which break up the remaining ice and accelerate its melt.

"Implications are serious: the increased open water lowers the average albedo [reflectivity] of the planet, accelerating global warming; and we are also finding the open water causing seabed permafrost to melt, releasing large amounts of methane, a powerful greenhouse gas, to the atmosphere."
Threats and opportunities

Opinions vary on the date of the demise of summer sea ice, but the latest announcement will give support to those who err on the pessimistic side.

A recent paper from Reading University used statistical techniques and computers to estimate that between 5-30% of the recent ice loss was due to Atlantic Multi-decadal Oscillation - a natural climate cycle repeating every 65-80 years. It's been in warm phase since the mid 1970s.

But the rest of the warming, the paper estimates, is caused by human activity - pollution and clearing of forests.

If the ice continues to disappear in summer there will be opportunities as well as threats.

Some ships are already saving time by sailing a previously impassable route north of Russia.

Oil, gas and mining firms are jostling to exploit the Arctic - although they're being strongly opposed by environmentalists. Greenpeace has been protesting at drilling by the Russian giant Gazprom.

Among the many threats, the warming is bad for Arctic wildlife. Thanks to the influence of sea ice on the jet stream the changes could affect weather in the UK.

The changes - if they happen - could unlock frozen deposits of methane which would further overheat the planet.

Warmer seas could lead to more melting of Greenland's ice cap which would contribute to raising sea levels and changing the salinity of the sea, which in turn could alter ocean currents that help govern our climate.

- BBC/NASA

Arctic sea ice levels to reach record low within days

North Pole webcam picture taken on 22 August 2012 showing ice cap melting. Climate scientists expect the Arctic sea ice is on course to plummet to its lowest levels ever this weekend. Photograph: University of Washington/ North Pole Environmental Observatory/NOAA

The dramatic melt expected over the next week signals that global warming is having a major impact on the polar region.

Arctic sea ice is set to reach its lowest ever recorded extent as early as this weekend, in "dramatic changes" signalling that man-made global warming is having a major impact on the polar region.

With the melt happening at an unprecedented rate of more than 100,000 sq km a day, and at least a week of further melt expected before ice begins to reform ahead of the northern winter, satellites are expected to confirm the record – currently set in 2007 – within days.

"Unless something really unusual happens we will see the record broken in the next few days. It might happen this weekend, almost certainly next week," Julienne Stroeve, a scientist at the US National Snow and Ice Data Centre (NSIDC) in Boulder, Colorado, told the Guardian.

"In the last few days it has been losing 100,000 sq km a day, a record in itself for August. A storm has spread the ice pack out, opening up water, bringing up warmer water. Things are definitely changing quickly."

Because ice thickness, volume, extent and area are all measured differently, it may be a week before there is unanimous agreement among the world's cryologists (ice experts) that 2012 is a record year. Four out of the nine daily sea ice extent and area graphs kept by scientists in the US, Europe and Asia suggest that records have already been broken. "The whole energy balance of the Arctic is changing. There's more heat up there. There's been a change of climate and we are losing more seasonal ice. The rate of ice loss is faster than the models can capture [but] we can expect the Arctic to be ice-free in summer by 2050," said Stroeve.

"Only 15 years ago I didn't expect to see such dramatic changes – no one did. The ice-free season is far longer now. Twenty years ago it was about a month. Now it's three months. Temperatures last week in the Arctic were 14C, which is pretty warm."

Scientists at the Danish Meteorological Institute, the Arctic Regional Ocean Observing System in Norway and others in Japan have said the ice is very close to its minimum recorded in 2007. The University of Bremen, whose data does not take into account ice along a 30km coastal zone, says it sees ice extent below the all-time record low of 4.33m sq km recorded in September 2007.

Ice volume in the Arctic has declined dramatically over the past decade. The 2011 minimum was more than 50% below that of 2005. According to the Polar Science Centre at the University of Washington it now stands at around 5,770 cubic kilometres, compared with 12,433 cu km during the 2000s and 6,494 cu km in 2011. The ice volume for 31 July 2012 was roughly 10% below the value for the same day in 2011. A new study by UK scientists suggests that 900 cu km of summer sea ice has disappeared from the Arctic ocean over the past year.

Arctic sea ice Photograph: guardian.co.uk

The consequences of losing the Arctic's ice coverage for the summer months are expected to be immense. If the white sea ice no longer reflects sunlight back into space, the region can be expected to heat up even more than at present. This could lead to an increase in ocean temperatures with unknown effects on weather systems in northern latitudes.

In a statement, a Greenpeace spokesman said: "The disappearing Arctic still serves as a stark warning to us all. Data shows us that the frozen north is teetering on the brink. The level of ice 'has remained far below average' and appears to be getting thinner, leaving it more vulnerable to future melting. The consequences of further rapid ice loss at the top of the world are of profound importance to the whole planet. This is not a warning we can afford to ignore."

Longer ice-free summers are expected to open up the Arctic ocean to oil and mining as well as to more trade. This year at least 20 vessels are expected to travel north of Russia between northern Europe and the Bering straits. Last week a Chinese icebreaker made the first voyage in the opposite direction.

"Every one of the 56,000 Inuits in Greenland have had to adapt to the retreat of the ice," said Carl-Christian Olsen, president of the Inuit Circumpolar Council in Nuuk, Greenland. "The permafrost is melting and this is jeopardising roads and buildings. The coastline is changing, there is more erosion and storms, and there are fewer mammals like polar bears. It means there can be more mining, which is good for the economy, but it will have unpredictable effects on social change".

Research published in Nature today said that warming in the Antarctic peninsula, where temperatures have risen about 1.5C over the past 50 years, is "unusual" but not unprecedented relative to natural variation. The research by Robert Mulvaney of the British Antarctic Survey, Cambridge, based on an ice-core record, showed that the warming of the north-eastern Antarctic peninsula began about 600 years ago. Temperature increases were said to be within the bounds of natural climate variability.

The difference between the rate of warming at the two poles is attributed to geographical differences. "Antarctica is a continent surrounded by water, while the Arctic is an ocean surrounded by land. Wind and ocean currents around Antarctica isolate the continent from global weather patterns, keeping it cold. In contrast, the Arctic Ocean is intimately linked with the climate systems around it, making it more sensitive to changes in climate," said a spokesman for the NSIDC.

• This article was amended on 24 August 2012 to restore to the start of the penultimate paragraph the words "Research published in Nature today", which had been lost in the editing process, and to clarify that the research was about temperatures in the Antarctic peninsula.

-  The Gaurdian

Arctic sea ice likely to hit record low next week

(Reuters) - Sea ice in the Arctic Ocean is likely to shrink to a record small size sometime next week, and then keep on melting, a scientist at the U.S. National Snow and Ice Data Center said on Monday.

"A new daily record ... would be likely by the end of August," said Ted Scambos, lead scientist at the data center, which monitors ice in the Arctic and elsewhere. "Chances are it will cross the previous record while we're still in sea ice retreat."

The amount of sea ice in the Arctic is important because this region is a potent global weather-maker, sometimes characterized as the world's air conditioner. This year, the loss of sea ice in the Arctic has suggested a possible opening of the Northwest Passage north of Canada and Alaska and the Northern Sea Route by Europe and Siberia.

As parts of the Arctic melted, 2012 also set records for heat and drought in much of the Northern Hemisphere temperate zone, especially the continental United States.

This summer could see the ice retreat to less than 1.5 million square miles (4 million square km), an unprecedented low, Scambos said.

The previous record was set in 2007, when Arctic ice cover shrank to 1.66 million square miles (4.28 million square km), 23 percent below the earlier record set in 2005 and 39 percent below the long-term average from 1979 to 2000.

However, 2007 was a jaw-dropping "perfect storm" of conditions that primed the area for thawing sea ice: warmer and sunnier than usual, with extremely warm ocean water and winds all working together to melt the Arctic.

Last year, Arctic sea ice extended over the second-smallest area on record, but that was considered to be closer to a "new normal" rather than the extreme conditions of 2007, NSIDC said then.

This year is similar to 2011, Scambos said by telephone from Colorado. The melt season started between 10 days to two weeks earlier than usual in some critical areas including northern Europe and Siberia.

SIGNS OF CLIMATE CHANGE

If the sea ice record is broken this month, that would be unusually early in the season; last year's low point came on September 9, 2011.

Typically, the melting of Arctic sea ice slows down in August as the Northern Hemisphere moves toward fall, but this year, it has speeded up, Scambos said. "I doubt there's been another year that had as rapid an early August retreat," he said.

Overall, the decline of Arctic sea ice has happened faster than projected by the United Nations Intergovernmental Panel on Climate Change five years ago, according to NSIDC data ( here ).

To Scambos, these are clear signs of climate change spurred by human activities, notably the emission of heat-trapping greenhouse gases including carbon dioxide.

"Everything about this points in the same direction: we've made the Earth warmer," he said.

This summer has also seen unusual melting of the ice sheet covering Greenland, with NASA images showing that for a few days in July, 97 percent of the northern island's surface was thawing. The same month also saw an iceberg twice the size of Manhattan break free from Greenland's Petermann Glacier.

The change is apparent from an NSIDC graphic showing current Arctic ice cover compared with the 1979-2000 average, Scambos said. The graphic is online at nsidc.org/arcticseaicenews/ .

"What you're seeing is more open ocean than you're seeing ice," he said. "It just simply doesn't look like what a polar scientist expects the arctic to look like. It's wide open and the (ice) cap is very small. It's a visceral thing. You look at it and that just doesn't look like the Arctic Ocean any more."

- Reuters

2012 Arctic Cyclone

n unusually strong storm formed off the coast of Alaska on August 5, 2012, and tracked into the center of the Arctic Ocean, where it lingered for several days. The Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the Aqua satellite captured this natural-color image on August 7, 2012. The center of the storm was located in the middle of the Arctic Ocean at the time.

The storm had an unusually low central pressure area. “It’s an uncommon event, especially because it’s occurring in the summer,” said Paul Newman, chief scientist for atmospheric sciences at NASA’s Goddard Space Flight Center. “Polar lows are more usual in the winter.” Newman estimated that there have only been about eight storms of similar strength during the month of August over the past 34 years of satellite records.

“It seems that this storm has detached a large chunk of ice from the main sea ice pack,” said Claire Parkinson, a climate scientist at NASA Goddard who studies ice. “This could lead to a more serious decay of the summertime ice cover than would have been the case otherwise, even perhaps leading to a new Arctic sea ice minimum.”

Arctic storms can have a large impact on sea ice, causing it to melt rapidly. Storms can tear off large swaths of ice and push them to warmer sites; they can churn the ice and make it slushier; or they can pull warmer waters up from the depths of the Arctic Ocean. “Decades ago, a storm of the same magnitude would have been less likely to have as large an impact on the sea ice because the ice cover was thicker and more expansive,” Parkinson added.

NASA image by Jeff Schmaltz, LANCE/EOSDIS Rapid Response. Caption by Maria-Jose Vinas.

Instrument: 

Aqua - MODIS - NASA

Rescue plane leaves Antarctica after picking up patient

A C-17 Globemaster III taxis off the annual sea ice runway near McMurdo Station, Antarctica Nov. 26, 2007 during Operation Deep Freeze. C-17s fly large cargo loads from Christchurch New Zealand to Antarctica while the LC-130 Hercules, stationed at McMurdo, fly smaller cargo loads to research posts throughout the continent.
CREDIT: U.S. Air Force photo/Tech. Sgt. Shane A. Cuomo.

(CNN) -- A dramatic medical evacuation mission played out Thursday as an aircraft picked up a patient from a research station in Antarctica, landing on a ice runway during a narrow window of "twilight" in the continent's dark winter.

While officials apparently found a weather break, nature offered a chilly reception at McMurdo Station, where temperatures Thursday were -13 degrees Fahrenheit (-25 Celsius), according to the U.S. Antarctic Program.

An Australian medical team, asked by the United States to assist, flew on an A319 Airbus from Christchurch, New Zealand. The team arrived at McMurdo Station about 1:15 p.m. Thursday New Zealand time (9:15 p.m. ET Wednesday) to pick up the unidentified patient, said Patti Lucas, spokeswoman for the Australian Antarctic Division.

The plane didn't stay on the ground for long: it was back in the air by around 2:30 p.m. New Zealand time, said Debbie Wing, a spokeswoman for the U.S. National Science Foundation, which oversees the facility. It is expected to arrive back in Christchurch a little after 6 p.m.

The patient, believed to be an American citizen, was in stable condition before the plane's arrival, Wing said.

The mission to the hub of the U.S. Antarctic Program was occurring during the Antarctic winter, when there is virtually no daylight for six months. No U.S. aircraft were in position to respond quickly.

Wing said she could not say whether the person's condition is life-threatening. But the patient requires medical attention beyond what can be provided by the medical team at the research facility, which Wing said is "like a portable hospital unit." Corrective surgery may be required.

There is currently "some twilight at midday," which may help the pilot see when making a landing at McMurdo, which has one of the few runways on the continent that can accommodate aircraft with wheels, Wing said.

From the archives: Stranded American researcher rescued from South Pole

Wing said she could not say whether the patient became sick or injured while at the facility, but she noted that there is "a very rigorous health screening process that you must go through" to be at the facility. "I would assume that the person did not go with any existing condition that would have posed a problem."

McMurdo can have nearly 1,500 people during the regular season, but during the winter, there are only about 60 to 70 people there, Wing said. There are no regular flights at this time of year.

From the archives: Doctor rescued from Antarctica in 1999 dies at 57

Nations "work together very cooperatively" in such situations, Dr. Tony Fleming, director of the Australian Antarctic Division, said in a statement.

The station, established in 1955, is built on bare volcanic rock on Ross Island, the solid ground farthest south that is accessible by ship, according to the NSF, an independent U.S. government agency. It has landing strips on sea ice and shelf ice, as well as a helicopter pad.

Researchers there conduct studies in astrophysics, biology, medicine, geology, glaciology and ocean and climate systems.

In September 2010, New Zealand's air force evacuated an American man at McMurdo. The first flight had to turn back because of heavy snow and limited visibility. The second flight touched down in the freezing weather and got the man out. Earlier in 2010, New Zealand rescued another sick American from McMurdo.

Last October, an American researcher who suffered a suspected stroke while working at the South Pole was rescued by the U.S. Air Force. She was flown from the South Pole to McMurdo Station, then on to Christchurch.

American Dr. Jerri Nielsen caught the nation's attention in 1999, when she found a lump in her breast as a 47-year-old physician stationed at the Amundsen-Scott South Pole Research Station.

After finding the lump, she diagnosed herself with breast cancer and began treating herself using chemotherapy agents that the U.S. Air Force parachuted to the station the next month.

It was later revealed, according to a March 2009 article in the Detroit Free Press newspaper, that Nielsen -- an emergency room doctor from Cleveland, Ohio -- performed a biopsy on herself with the help of non-medical crew, who practiced using needles on a raw chicken.

Her cancer later returned and Nielsen, 57, died in 2009.

-CNN

International rescue mission under way in Antarctica

An international mission to rescue a sick US scientist is under way in the depths of an Antarctic winter.

An Australian Airbus A319 has landed at an icy runway of the US McMurdo station, after a five-hour flight from Christchurch in New Zealand.

The US requested help from Australia, saying the scientist - who has not been identified - may require treatment beyond that available at the base.

New Zealand's air force is monitoring the rescue operation.

"The patient is currently stable but may require immediate corrective surgery," a statement by the US National Science Foundation (NSF) said.

It added that the base was "not equipped for the type of procedure being contemplated".

It was not immediately known when the Australian aircraft would leave McMurdo.

The base's runway is one of the few in the Antarctic that remains operational for much of the year, despite the polar darkness and hostile conditions.

- BBC

Supermoon Lights Up South Pole

Soon after the 24-hour darkness of Antarctic winter descended on the United States' Amundsen-Scott Station at the South Pole, the crew of scientists and staff overwintering there got a much-welcomed dose of very bright moonlight.

In early May, a gleaming supermoon appeared — this full moon coincides with the moon's perigee, or closest monthly pass of the Earth.

Thanks to that quirk of timing, a supermoon appears larger and brighter than a typical full moon, and crews at the South Pole station took full advantage of the extra light, completing as much outside maintenance as possible.

- OurAmazingPlanet

Methane Leaking through the Cracks

The fragile and rapidly changing Arctic is home to large reservoirs of methane, a potent greenhouse gas. As Earth’s climate warms, that methane is vulnerable to possible release into the atmosphere, where it can add to global warming.
Researchers have known for years that large amounts of methane are frozen in Arctic tundra soils and in marine sediments (including gas hydrates). But now a multi-institutional study led by Eric Kort of NASA’s Jet Propulsion Laboratory has uncovered a surprising and potentially important new source of methane: the Arctic Ocean itself.


The photograph above was taken by Kort, and it shows leads and cracks in the ice cover of the Arctic Ocean north of Alaska. During five research flights in 2009–10, Kort and colleagues measured increased methane levels while flying at low altitudes north of the Chukchi and Beaufort Seas in a National Science Foundation/National Center for Atmospheric Research (NCAR) Gulfstream V aircraft as part of the HIAPER Pole-to-Pole Observations (HIPPO) airborne campaign.
The methane level detected during the flights was about one-half percent higher than normal background levels.
 But where was the methane coming from? The team detected no carbon monoxide in the atmosphere, which would have been a signature of methane coming from the human combustion of fuels. And based on the time of year, the location, and the nature of the emissions, it was unlikely that the methane was coming from high-latitude wetlands or geologic reservoirs.



By comparing the locations of the enhanced methane levels with airborne measurements of carbon monoxide, water vapor, and ozone, the researchers from six institutions pinpointed a source: the ocean surface, in places where there were cracks and openings in the sea ice cover. The cracks were allowing methane in the top layers of the sea to escape into the atmosphere. The team did not detect enhanced methane levels over areas of solid ice.
Kort noted that previous studies had detected high concentrations of methane in Arctic surface waters, but no one had predicted that this dissolved methane would find its way into the overlying atmosphere. Scientists are not yet sure how the methane is produced, but Kort suspects biological productivity in Arctic surface waters may be the culprit.
“It's possible that as large areas of sea ice melt and expose more ocean water, methane production may increase, leading to larger methane emissions,” he said. “While the methane levels we detected weren't particularly large, the potential source region, the Arctic Ocean, is vast. So our finding could represent a noticeable new global source of methane.”



References:
Kort, E.A., et al (2012) Atmospheric observations of Arctic Ocean methane emissions up to 82° north. Nature Geoscience 5, 318–321.
Courtesy Eric Kort, Jet Propulsion Laboratory. Caption based on a text by Alan Buis, JPL. The research was funded by the National Science Foundation, with additional support from the National Center for Atmospheric Research, NASA, and the National Oceanic and Atmospheric Administration.

Instrument:
Photograph - NASA

A Mélange of Ice

(Click on images for larger view.)

For the fourth consecutive year, NASA research aircraft are flying over the Arctic to assess the health of the ice in the fast-changing region. Global warming has had a particularly strong impact on the Arctic, yet the effects on the region’s ice have been anything but steady or predictable. Some glaciers are spitting out icebergs and draining the Greenland ice sheet at an alarming pace; others are barely moving; a few are growing thicker.

The flights are part of a six-year mission called IceBridge. The airborne campaign allows scientists to keep an eye on the complex dynamics of the ice, helping them project how much melting ice sheets might elevate sea level and how fast sea ice is likely to retreat. Funded and structured like a satellite mission, IceBridge continues measurements started by the Ice, Cloud, and Land Elevation Satellite (ICESat) in 2003.

ICESat stopped collecting data in 2009, making IceBridge critical for ensuring a continuous series of observations until ICESat-2 launches in 2016. IceBridge flights also collect data useful for climate modeling that ICESat could not, including measures of the land topography beneath the ice, grounding line position, and ice and snow thickness.

The top image, captured during an IceBridge flight, shows a glacier in eastern Greenland flowing through a long and narrow valley—a fjord—carved by the movement of ice. Where the edge of the glacier meets the sea, there’s a layer of floating ice dimpled with chunks of icebergs that have broken off from the glacier. Understanding ice mélanges, as these conglomerations are called, is important because there is evidence that they can slow the rate that glaciers like this slip into the sea. The photograph was taken with a camera aboard NASA’s P-3B aircraft on April 25, 2012.

The image below shows a closer view of a different ice mélange; the blue patch in the middle of the image is possibly the result of turbulence from a recent calving event. Because of the disturbance, the ice appears to be thinner and more transparent to the water below. In addition, the underside of ice from glaciers often has a blue color, so it’s not unusual for ice that recently broke off from a glacier to appear this color. This photograph, also captured during a P-3B flight, was taken on April 14.

This year’s Arctic campaign stands out for completing several more sea ice flights than in previous years and for covering a greater distance. Another highlight: the IceBridge team recently flew a set of coordinated flights with European Space Agency aircraft in order to verify ice thickness measurements made by CryoSat-2.

Throughout the campaign, scientists in the field have been sending back dispatches via the mission’s blog. “The once seemingly insignificant and remote Arctic region is now understood to be intimately connected to the rest of the planet,” noted Goddard Space Flight Center’s Nathan Kurtz in a post published on March 27. “Sea ice variability affecting the severity of snow storms in Europe, melting sea ice increasing the absorption of sunlight by the Earth, and melting ice sheets causing sea level rise are but a few of many such connections.“

References:
Riebeek, H. (2011) IceBridge: Building a Record of Earth's Changing Ice, One Flight at a Time. NASA’s Earth Observatory.
NASA. (2012) IceBridge: Arctic: 2012. Accessed May 2, 2012.
NASA. (2012) Operation IceBridge Blog. Accessed May 2, 2012.
Amundson, J. (2012). Ice Mélange Dynamics and Implications for Terminus Stability, Jakobshavn Isbræ, Greenland Journal of Geophysical Research Earth Surfaces. 001(405).
NASA images from the IceBridge Science Team and taken by Jefferson Beck and Maria-José Viñas. Image interpretation by Bob Bindschadler and Sophie Nowicki. Caption by Adam Voiland with reporting from George Hale and Holli Riebeek.

Instrument:
Photograph - NASA

Sunny Skies over the Antarctic Peninsula

(Click on images for larger view.)

Sunny skies and westerly winds prevailed over the Antarctic Peninsula on April 24, 2012. Cloudy weather had just moved out, and temperatures rose well above freezing as the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite passed overhead and captured a natural-color image (top).

The relatively warm conditions on the peninsula in late April 2012 were driven in part by warm downslope winds, known as Chinook or foehn winds, that were channeled through valleys such as the one holding the Flask Glacier. Such winds can lead to extensive melt in the summer.

Scientists can access timely weather information from the Antarctic Peninsula thanks to a group of remote, satellite-linked weather stations known as the Automated Met-Ice-Geophysics Observation System (AMIGOS). Deployed in 2010–11, AMIGOS stations are part of a National Science Foundation-funded project to study environmental change in the rapidly changing area around the Larsen Ice Shelf. Each station is equipped with a thermometer, instruments to measure wind speed and direction, and a camera to photograph its surroundings. Stations installed on the flowing ice have also been equipped with global positioning system (GPS) receivers to track changes in flow speed.

Glaciologists have good reason to watch the Antarctic Peninsula. In 2002, the massive Larsen B ice shelf disintegrated in a matter of weeks. The calving front at the SCAR Inlet is the remaining fragment of that much larger shelf. (The inlet is named for the Scientific Committee on Antarctic Research.)

Temperature and wind conditions in late April 2012 came from the AMIGOS 3 station on Flask Glacier, and the AMIGOS 6 station at Cape Disappointment. The second image above is a photo taken by AMIGOS 6 on April 24 and relayed to a satellite the same day. The view is toward the south, showing part of the SCAR Inlet calving front. The Flask Glacier appears in the distance.

As of April 2012, the AMIGOS 1 station was set for deployment on a future expedition. The AMIGOS 2 station, a prototype, was operating on the roof of the National Snow and Ice Data Center in Boulder, Colorado. Located on the stormy ridge of the crest of the Peninsula, the AMIGOS 5 station stopped sending data after seven months, being completely buried by roughly 6 meters (20 feet) of snow.

Although conditions were relatively warm on April 24, cool conditions prevailed on the Peninsula in the months preceding this image—much cooler than the conditions prior to the Larsen B Ice Shelf disintegration in 2002. The fast ice filling the area of the SCAR Inlet was evidence that conditions were cooler than normal. That ice remained in place through the austral summer of 2011–12. Meanwhile, summer melt ponds, thought to contribute to the breakup of the Larsen B Ice Shelf, were scarce from 2010 to 2012.

References:
National Snow and Ice Data Center. (2011, November 1) On Thin Ice: Expedition to a crumbling Antarctic ice shelf. Accessed April 30, 2012.
Hamilton University. (2012, April 15) 2012 Expedition to Antarctica. Accessed April 30, 2012.
NASA Earth Observatory image by Jesse Allen, using data from the Land Atmosphere Near real-time Capability for EOS (LANCE). Caption by Michon Scott with information from Ted Scambos and Terry Haran, National Snow and Ice Data Center.

Instrument:
Terra - MODIS - NASA

Antarctic ice melting from warm water below

Antarctica's massive ice shelves are shrinking because they are being eaten away from below by warm water, a new study finds. That suggests that future sea levels could rise faster than many scientists have been predicting.

The western chunk of Antarctica is losing seven metres of its floating ice sheet each year. Until now, scientists weren't exactly sure how it was happening and whether or how man-made global warming might be a factor. The answer, according to a study published early today (NZ time) in the journal Nature, is that climate change plays an indirect role — but one that has larger repercussions than if Antarctic ice were merely melting from warmer air.

Hamish Pritchard, a glaciologist at the British Antarctic Survey, said research using an ice-gazing Nasa satellite showed that warmer air alone couldn't explain what was happening to Antarctica. A more detailed examination found a chain of events that explained the shrinking ice shelves.

Twenty ice shelves showed signs that they were melting from warm water below. Changes in wind currents pushed that relatively warmer water closer to and beneath the floating ice shelves. The wind change is likely caused by a combination of factors, including natural weather variation, the ozone hole and man-made greenhouse gases, Pritchard said in a phone interview.

As the floating ice shelves melt and thin, that in turn triggers snow and ice on land glaciers to slide down to the floating shelves and eventually into the sea, causing sea level rise, Pritchard said. Thicker floating ice shelves usually keep much of the land snow and ice from shedding to sea, but that's not happening now.

That whole process causes larger and faster sea level rise than simply warmer air melting snow on land-locked glaciers, Pritchard said.

"It means the ice sheets are highly sensitive to relatively subtle changes in climate through the effects of the wind," he said.

What's happening in Antarctica "may have already triggered a period of unstable glacier retreat," the study concludes. If the entire Western Antarctic Ice Sheet were to melt — something that would take many decades if not centuries — scientists have estimated it would lift global sea levels by about 16 feet.

Nasa chief scientist Waleed Abdalati, an expert in Earth's ice systems who wasn't involved in the research, said Pritchard's study "makes an important advance" and provides key information about how Antarctica will contribute to global sea level rise.

Another outside expert, Ted Scambos of the National Snow and Ice Data Center, said the paper will change the way scientists think about melt in Antarctica. Seeing more warm water encircling the continent, he worries that with "a further push from the wind" newer areas could start shrinking.

- AP/Stuff.co.nz

Missing antarctic Russians still alive, battling through ice

A general view of the Vostock research camp in Antarctica. file picture Image by: HANDOUT / REUTERS

A Russian-Ukrainian sailing crew that went missing on a historic expedition around the South Pole is alive and made contact Saturday as it battled through Antarctic ice with its fuel running low.

The ambitious eight-strong team on the Scorpius yacht did not make contact earlier this week as gale-force winds slowed its progress. But the captain said in an email that the crew was in good health, the expedition's spokeswoman Anna Subbotina said.

"They contacted us with an email last night. The ice conditions were very severe, and currently they are going toward the mainland because they are running out of fuel and other supplies," she told AFP.

The 29-metre (97 foot) yacht was cut off from communication for several days after water damaged its satellite antennae during a storm on the way to Deception Island.

Currently the crew has fuel for only two-and-a-half days, and has decided to sail towards the Chilean mainland by circumventing the South Shetlands. "They are forcing their way through the ice, travelling very slowly," she said.

But the team appears to be in good spirits and nobody has been hurt, she added. "They are not asking for help," she said.

The Scorpius -- a sleek white steel yacht built in 1991 in the Netherlands -- left on its 130,000 kilometre voyage hoping to set a number of sailing records and restoring Russia's pride on the seas.

It hoped to become the first yacht to circle both the South and North Poles in the same year -- only a part of a mission that intends to stay at sea for a record 20 months.

The Scorpius set sail from Russia's Black Sea port city of Sochi on September 18 before passing the Canary Islands off the northwestern coast of Africa in November and then dipping below the southern bend of Argentina.

The team's crew comprises four Russians and four Ukranians at this stage of the journey.

- TIMES LIVE