Warming climate may release vast amounts of carbon from long-frozen Arctic soils

Michael Sullivan at the University of Georgia Today: While climatologists are carefully watching carbon dioxide levels in the atmosphere, another group of scientists is exploring a massive storehouse of carbon that has the potential to significantly affect the climate change picture.

University of Georgia Skidaway Institute of Oceanography researcher Aron Stubbins is part of a team investigating how ancient carbon, locked away in Arctic permafrost for thousands of years, is now being transformed into carbon dioxide and released into the atmosphere. The results of the study were published in Geophysical Research Letters.

The Arctic contains a massive amount of carbon in the form of frozen soil—the remnants of plants and animals that died more than 20,000 years ago. Because this organic material was permanently frozen year-round, it did not undergo decomposition by bacteria the way organic material does in a warmer climate. Just like food in a home freezer, it has been locked away from the bacteria that would otherwise cause it to decay and be converted to carbon dioxide.

"However, if you allow your food to defrost, eventually bacteria will eat away at it, causing it to decompose and release carbon dioxide," Stubbins said. "The same thing happens to permafrost when it thaws."

Scientists estimate there is more than 10 times the amount of carbon in the Arctic soil than has been put into the atmosphere by burning fossil fuels since the start of the Industrial Revolution. To look at it another way, scientists estimate there is two and a half times more carbon locked away in the Arctic deep freezer than there is in the atmosphere today. Now, with a warming climate, that deep freezer is beginning to thaw and that long-frozen carbon is beginning to be released into the environment.

"The study we did was to look at what happens to that organic carbon when it is released," Stubbins said. "Does it get converted to carbon dioxide or is it still going to be preserved in some other form?"

..."We found that decomposition converted 60 percent of the carbon in the thawed permafrost to carbon dioxide in two weeks," Stubbins said. "This shows the permafrost carbon is definitely in a form that can be used by the microbes."...

Permafrost thaw ponds in Hudson's Bay, shot by Steve Jurvetson, Wikimedia Commons via Flickr, under the Creative Commons Attribution 2.0 Generic license 

Polar code agreed to prevent Arctic environmental disasters

Karl Mathiesen in the Guardian (UK): The international body in charge of sea safety adopted measures on Friday to protect people and the environment during a predicted shipping rush in the Arctic. But environment groups and insurers said the International Maritime Organisation (IMO) Maritime Safety Committee had failed to address key issues including a proposed ban on heavy fuel oil and how to safeguard against cowboy operators.

The committee, which met in London this week, signed off on the Polar Code and various amendments to the Safety of Life at Sea (Solas) convention. These changes, which include mandatory requirements for ship design, crew training and search and rescue protocols, are expected to be ratified by the full IMO next year and come into force in 2017.

Melting sea ice due to global warming and pressure to cut costs makes the Arctic commercially enticing to shipping companies who want to avoid the circuitous, pirate-ridden voyage from China to Europe via the Suez Canal. Tourism, fishing and fossil fuel operations are also looking toward one of the world’s most fragile and extreme environments.

Evan Bloom, director of the US State Department’s Office of Ocean and Polar Affairs said: “More and more people are going to be in the Arctic for one reason or another. In the future there may be [more] fishing vessels... There will be more and more tourism. There will be more and more commerce.” He says this increases the likelihood of something going wrong in a region where there is currently very little capability to respond in either a search and rescue or environmental clean-up capacity.

...According to insurer Allianz, Russia predicts a 30-fold increase in shipping by 2020 and an ice-free Northern Sea Route by 2050. China has suggested that by 2020, 5-15% of its trade value - close to $500bn - could pass through the Arctic....

Sea ice off Baffin Island, via NASA

Record decline of ice sheets: For the first time scientists map elevation changes of Greenland and Antarctic glaciers

A press release from the Alfred Wegener Institute: Researchers from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI), have for the first time extensively mapped Greenland’s and Antarctica’s ice sheets with the help of the ESA satellite CryoSat-2 and have thus been able to prove that the ice crusts of both regions momentarily decline at an unprecedented rate. In total the ice sheets are losing around 500 cubic kilometres of ice per year. This ice mass corresponds to a layer that is about 600 metres thick and would stretch out over the entire metropolitan area of Hamburg, Germany's second largest city. The maps and results of this study are published today in The Cryosphere, an open access journal of the European Geoscience
s Union (EGU).

“The new elevation maps are snapshots of the current state of the ice sheets. The elevations are very accurate, to just a few metres in height, and cover close to 16 million km2 of the area of the ice sheets. This is 500,000 square kilometres more than any previous elevation model from altimetry”, says lead-author Dr. Veit Helm, glaciologist at the Alfred Wegener Institute in Bremerhaven.

For the new digital maps, the AWI scientists had evaluated all data by the CryoSat-2 altimeter SIRAL. Satellite altimeter measure the height of an ice sheet by sending radar or laser pulses in the direction of the earth. These signals are then reflected by the surface of the glaciers or the surrounding waters and are subsequently retrieved by the satellite. This way the scientists were able to precisely determine the elevation of single glaciers and to develop detailed maps.

...The team derived the elevation change maps using over 200 million SIRAL data points for Antarctica and around 14.3 million data points for Greenland. The results reveal that Greenland alone is reducing in volume by about 375 cubic kilometres per year. “When we compare the current data with those from the ICESat satellite from the year 2009, the volume loss in Greenland has doubled since then. The loss of the West Antarctic Ice Sheet has in the same time span increased by a factor of 3. Combined the two ice sheets are thinning at a rate of 500 cubic kilometres per year. That is the highest speed observed since altimetry satellite records began about 20 years ago,” says AWI glaciologist Prof. Dr. Angelika Humbert, another of the study’s authors.

The areas where the researchers detected the largest elevation changes were Jakobshavn Isbrae (Jakobshavn Glacier) in West Greenland and Pine Island Glacier in West Antarctica. Since February 2014 scientists know that the Jakobshavn Isbrae is moving ice into the ocean at a record rate of up to 46 meters a day. The Pine Island Glacier hit the headlines in July 2013. Back then AWI scientists reported that a table iceberg as large as the area of Hamburg had broken off the tip of its ice shelf. (Link to the AWI press release from the 9th July 2013)

But whereas both the West Antarctic Ice Sheet and the Antarctic Peninsula, on the far west of the continent, are rapidly losing volume, East Antarctica is gaining volume – though at a moderate rate that doesn’t compensate the losses on the other side of the continent....

The border of an Antarctic glacier, photo from the Alfred Wegener Institute

Minor variations in ice sheet size can trigger abrupt climate change

AlphaGalileo via Cardiff University: Small fluctuations in the sizes of ice sheets during the last ice age were enough to trigger abrupt climate change, scientists have found. The team, which included Cardiff University researchers, compared simulated model data with that retrieved from ice cores and marine sediments in a bid to find out why temperature jumps of up to ten degrees took place in far northern latitudes within just a few decades during the ice age.

...The research confirms that thicker ice sheets increased ocean circulation and transferred more heat to the north due to a redirection of the prevailing winds. As the north warmed, glaciers retreated, the winds returned to normal conditions, and the north became cooler once again, completing the cycle

Conor Purcell from Cardiff University’s School of Earth and Ocean Sciences, said: “Using the simulations performed with our climate model, we were able to demonstrate that the climate system can respond to small changes with abrupt climate swings. Our study suggests that at medium sea levels, powerful forces, such as the dramatic acceleration of polar ice cap melting, are not necessary to create abrupt climate shifts and temperature changes.”

At present, the extent of Arctic sea ice is far less than during the last glacial period. The Laurentide Ice Sheet, the major driving force for ocean circulation during the glacials, has also disappeared. Climate changes following the pattern of the last ice age are therefore not anticipated under today’s conditions.

Professor Gerrit Lohmann, leader of the Paleoclimate Dynamics group at the AWI said: “In terms of the Earth’s history, we are currently in one of the climate system’s more stable phases. The preconditions which gave rise to rapid temperature changes during the last ice age do not exist today, but sudden climate changes cannot be excluded in future.”

The Greenland Ice Sheet, shot by Christine Zenino, Wikimedia Commons via Flickr,  under the Creative Commons Attribution 2.0 Generic license

Study links California drought, polar vortex to climate change

Kevin Opsahl in Idaho State Journal:  A Utah State University study has found a link between climate change and two of the biggest extreme weather events that have played out in the first half of the year — the California drought and the polar vortex.

The new study blames an unusual “dipole,” a combination of a strong Western high pressure ridge and a deep Great Lakes low pressure trough. That dipole is linked to a recently found precursor to El Nino, the weather-changing phenomenon. And that precursor itself seems amplified by a buildup of heat-trapping greenhouse gases, the study says.

 The author of the study, Simon Wang, saw the precursors and weather event coming months before federal weather officials issued an official El Nino watch last month. Wang is assistant director of the Utah Climate Center — a state research facility based at USU — and worked with other professors on the study, which is set to be published in Geophysical Research Letters.

“I believe we have uncovered another important piece to link to extreme events in North America,” said Wang in an interview on Wednesday. “The first thing (people should know) is to prepare better next time a similar event hits because this 'dipole' is increasingly likely to happen again with greater intensity. ... This extreme event is not really random and is potentially traceable/predictable, and the pathway from which human-induced warming affects individual climate extreme events (is) complex but identifiable.”

The study’s findings can better help water managers and energy suppliers plan for the future, Wang said. Below-average rainfall has put the entire Golden State in drought, ranging from moderate to exceptional for the first time in 15 years, according to the Los Angeles Times. The polar vortex — which occurred at the beginning of the year — was a powerful high pressure system originating in the Eastern Pacific stretching to the North Pole, shoving the vortex farther south than is typical, allowing it to settle in Canada and the U.S....

Chicago during the 2014 winter, shot by akasped, Wikimedia Commons via Flickr, under the Creative Commons Attribution 2.0 Generic license

New NASA laser technology reveals how ice measures up

Science Daily: New results from NASA's MABEL campaign demonstrated that a photon-counting technique will allow researchers to track the melt or growth of Earth's frozen regions. When a high-altitude aircraft flew over the icy Arctic Ocean and the snow-covered terrain of Greenland in April 2012, it was the first polar test of a new laser-based technology to measure the height of Earth from space.

NASA's Multiple Altimeter Beam Experimental Lidar flew over Southwest Greenland's glaciers and sea ice to test a new method of measuring the height of Earth from space.

Aboard that aircraft flew the Multiple Altimeter Beam Experimental Lidar, or MABEL, which is an airborne test bed instrument for NASA's ICESat-2 satellite mission slated to launch in 2017. Both MABEL and ICESat-2's ATLAS instrument are photon counters -- they send out pulses of green laser light and time how long it takes individual light photons to bounce off Earth's surface and return. That time, along with ATLAS' exact position from an onboard GPS, will be plugged into computer programs to tell researchers the elevation of Earth's surface -- measuring change to as little as the width of a pencil.

This kind of photon-counting technology is novel for satellites; from 2003 to 2009, ICESat-1's instrument looked at the intensity of a returned laser signal, which included many photons. So getting individual photon data from MABEL helps scientists prepare for the vast amounts of elevation data they'll get from ICESat-2.

"Using the individual photons to measure surface elevation is a really new thing," said Ron Kwok, a senior research scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "It's never been done from orbiting satellites, and it hasn't really been done much with airborne instruments, either."...

I can see my house from here. Actually, it's an aerial shot of Greenland, shot by Túrelio, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 2.5 Generic license

New report calls for attention to abrupt impacts from climate change, emphasizes need for early warning system

A press release from the National Academy of Sciences: Climate change has increased concern over possible large and rapid changes in the physical climate system, which includes the Earth's atmosphere, land surfaces, and oceans.  Some of these changes could occur within a few decades or even years, leaving little time for society and ecosystems to adapt.  A new report from the National Research Council extends this idea of abrupt climate change, stating that even steady, gradual change in the physical climate system can have abrupt impacts elsewhere -- in human infrastructure and ecosystems for example -- if critical thresholds are crossed.  The report calls for the development of an early warning system that could help society better anticipate sudden changes and emerging impacts.

"Research has helped us begin to distinguish more imminent threats from those that are less likely to happen this century," said James W.C. White, professor of geological sciences at the University of Colorado, Boulder, and chair of the committee that wrote the report.  "Evaluating climate changes and impacts in terms of their potential magnitude and the likelihood they will occur will help policymakers and communities make informed decisions about how to prepare for or adapt to them."

Abrupt climate changes and impacts already under way are of immediate concern, the report says.  These include the disappearance of late-summer Arctic sea ice and increases in extinction rates of marine and terrestrial species.

Other scenarios, such as the destabilization of the west Antarctic ice sheet, have potentially major consequences, but the probability of these changes occurring within the next century is not well-understood, highlighting the need for more research.

In some cases, scientific understanding has progressed enough to determine whether certain high-impact climate changes are likely to happen within the next century.  The report notes that a shutdown in the Atlantic Ocean circulation patterns or a rapid release of methane from high-latitude permafrost or undersea ice are now known to be unlikely this century, although these potential abrupt changes are still worrisome over longer time horizons....

The calving front of the Pine Island Glacier in Antarctica, shot by NASA ICE, Wikimedia Commons via Flickr, under the Creative Commons Attribution 2.0 Generic licens

Thawing permafrost: The speed of coastal erosion in Eastern Siberia has nearly doubled

Alfred Wegener Institute: The high cliffs of Eastern Siberia – which mainly consist of permafrost – continue to erode at an ever quickening pace. This is the conclusion which scientists of the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research have reached after their evaluation of data and aerial photographs of the coastal regions for the last 40 years. According to the researchers, the reasons for this increasing erosion are rising summer temperatures in the Russian permafrost regions as well the retreat of the Arctic sea ice. This coastal protection recedes more and more on an annual basis. As a result, waves undermine the shores. At the same time, the land surface begins to sink. The small island of Muostakh east of the Lena Delta is especially affected by these changes. Experts fear that it might even disappear altogether should the loss of land continue.

The interconnectedness is clear and unambiguous: The warmer the east Siberian permafrost regions become, the quicker the coast erodes. “If the average temperature rises by 1 degree Celsius in the summer, erosion accelerates by 1.2 metres annually,“ says AWI geographer Frank Günther, who investigates the causes of the coastal breakdown in Eastern Siberia together with German and Russian colleagues, and who has published his findings in two scientific articles.

...This increase in temperature is not without consequences. Whereas a thick layer of sea ice used to protect the frozen soil almost all year round, it now recedes in this part of the Arctic for increasing periods of time during the summer months. The number of summer days on which the sea ice in the southern Laptew Sea vanishes completely grows steadily. “During the past two decades, there were, on average, fewer than 80 ice-free days in this region per year. During the past three years, however, we counted 96 ice-free days on average. Thus, the waves can nibble at the permafrost coasts for approximately two more weeks each year,“ explains AWI permafrost researcher Paul Overduin.

The waves dig deep recesses into the base of the high coasts. The result: The undermined slopes break off bit by bit. During the past 40 years, the coastal areas surveyed retreated on average 2.2 meters per year. “During the past four years, this value has increased at least 1.6 times, in certain instances up to 2.4 times to reach 5.3 meters per year,“ says Paul Overduin.

For the little island of Muostakh east of the harbour town of Tiksi, this may well mean extinction. “In fewer than one hundred years, the island will break up into several sections, and then it will disappear quickly,“ predicts Frank Günther....

Waiting for supplies in Eastern Siberia, shot by NASA ICE, Wikimedia Commons via Flickr, under the Creative Commons Attribution 2.0 Generic license

Stressed krill first sign of damage

Andrew Darby in the Sydney Morning Herald: Turns out it's the little things we need to worry about in climate change. When they're in trouble, a great polar ecosystem may be, too.

The oceans are now absorbing so much carbon dioxide they are acidifying at an unprecedented rate, according to the International Program on the State of the Ocean. Geological records show the current acidification is unparalleled in at least the past 300 million years, IPSO's latest State of the Ocean report says. ''We are entering an unknown territory of marine ecosystem change, and exposing organisms to intolerable evolutionary pressure,'' it says.

The smallest of these creatures in the remote Antarctic marine ecosystem are said to be showing some of the earliest signs of acidification damage. And work by Australian scientists shows greater problems lie in store for the creatures at the centre of the Antarctic food web - krill.

Environment Minister Greg Hunt pointed to warnings of increasing ocean acidification as the most important new advice from the Intergovernmental Panel on Climate Change's latest report. ''In the debate around climate change, research on acidification of the oceans is a particular personal concern,'' Mr Hunt said. ''This has been reinforced by the work of Australian scientists, particularly in the Antarctic.

''The Southern Ocean is specially vulnerable to increased acidity because of the cold water and the type of marine life. If there are changes in these environments, then there is a flow-on impact across the entire marine system.''...

Antarctic krill, shot by Uwe Kils, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

On warming Antarctic Peninsula, moss and microbes reveal unprecedented ecological change

Terra Daily via SPX: By carefully analyzing a 150-year-old moss bank on the Antarctic Peninsula, researchers reporting in Current Biology, a Cell Press publication, on August 29 describe an unprecedented rate of ecological change since the 1960s driven by warming temperatures.

"Whilst moss and amoebae may not be the first organisms that come to mind when considering Antarctica, they are dominant components of the year-round terrestrial ecosystem in the small ice-free zones during an austral summer," says Jessica Royles of the British Antarctic Survey and the University of Cambridge.

"We know from meteorological measurements and from the interpretation of signals preserved within ice and sediment cores that the climate of the Antarctic Peninsula has undergone substantial and rapid change. Our evidence, from the southernmost known moss bank, exploits an unusual biological archive and shows that the flora and fauna of the Antarctic Peninsula are very sensitive and have in the past responded, and continue to respond, to these changes in climate."

The researchers looked to the Antarctic Peninsula because it is one of the most rapidly warming regions on Earth; annual temperatures there have increased by up to 0.56 C per decade since the 1950s.

There they found a moss bank that has been slowly growing at the top surface and accumulating peat material since it first established in about 1860. By analyzing core samples of that moss bank, Royles, Matthew Amesbury of the University of Exeter, and their colleagues were able to characterize the growth and activity of the moss and microbes over time....

Brown Bluff on the Antarctic Peninsula, shot by Aman Malik, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported, 2.5 Generic, 2.0 Generic and 1.0 Generic license

East Antarctic Ice Sheet could be more vulnerable to climate change than previously thought

Durham University News: The world’s largest ice sheet could be more vulnerable to the effects of climate change than previously thought, according to new research from Durham University. A team from the Department of Geography used declassified spy satellite imagery to create the first long-term record of changes in the terminus of outlet glaciers – where they meet the sea – along 5,400km of the East Antarctic Ice Sheet’s coastline. The imagery covered almost half a century from 1963 to 2012.

Using measurements from 175 glaciers, the researchers were able to show that the glaciers underwent rapid and synchronised periods of advance and retreat which coincided with cooling and warming. The researchers said this suggested that large parts of the ice sheet, which reaches thicknesses of more than 4km, could be more susceptible to changes in air temperatures and sea-ice than was originally believed.

Current scientific opinion suggests that glaciers in East Antarctica are at less risk from climate change than areas such as Greenland or West Antarctica due to its extremely cold temperatures which can fall below minus 30°C at the coast, and much colder further inland.

But the Durham team said there was now an urgent need to understand the vulnerability of the East Antarctic Ice Sheet, which holds the vast majority of the world’s ice and enough to raise global sea levels by over 50m. The findings are published in the prestigious scientific journal Nature.

Dr Chris Stokes, in Durham’s Department of Geography, said: “We know that these large glaciers undergo cycles of advance and retreat that are triggered by large icebergs breaking off at the terminus, but this can happen independently from climate change. “It was a big surprise therefore to see rapid and synchronous changes in advance and retreat, but it made perfect sense when we looked at the climate and sea-ice data....

A 1913 shot of Adelie Land, from the National Library of Australia

Scientists outline long-term sea-level rise in response to warming of planet

Oregon State University News & Research Communications: A new study estimates that global sea levels will rise about 2.3 meters, or more than seven feet, over the next several thousand years for every degree (Celsius) the planet warms. This international study is one of the first to combine analyses of four major contributors to potential sea level rise into a collective estimate, and compare it with evidence of past sea-level responses to global temperature changes.

Results of the study, funded primarily by the National Science Foundation and the German Federal Ministry of Education and Research, are being published this week in the Proceedings of the National Academy of Sciences.

“The study did not seek to estimate how much the planet will warm, or how rapidly sea levels will rise,” noted Peter Clark, an Oregon State University paleoclimatologist and author on the PNAS article. “Instead, we were trying to pin down the ‘sea-level commitment’ of global warming on a multi-millennial time scale. In other words, how much would sea levels rise over long periods of time for each degree the planet warms and holds that warmth?”

“The simulations of future scenarios we ran from physical models were fairly consistent with evidence of sea-level rise from the past,” Clark added. “Some 120,000 years ago, for example, it was 1-2 degrees warmer than it is now and sea levels were about five to nine meters higher. This is consistent with what our models say may happen in the future.”

Scientists say the four major contributors to sea-level rise on a global scale will come from melting of glaciers, melting of the Greenland ice sheet, melting of the Antarctic ice sheet, and expansion of the ocean itself as it warms. Several past studies have examined each of these components, the authors say, but this is one of the first efforts at merging different analyses into a single projection.

The researchers ran hundreds of simulations through their models to calculate how the four areas would respond to warming, Clark said, and the response was mostly linear. The amount of melting and subsequent sea-level response was commensurate with the amount of warming. The exception, he said, was in Greenland, which seems to have a threshold at which the response can be amplified....

An iceberg in the high Arctic, a beautiful shot by Brocken Inaglory, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

New projections of 'uneven' global sea-level rise

EurekAlert via the British Antarctic Survey: Sophisticated computer modelling has shown how sea-level rise over the coming century could affect some regions far more than others. The model shows that parts of the Pacific will see the highest rates of rise while some polar regions will actually experience falls in relative sea levels due to the ways sea, land and ice interact globally.

Reporting in the journal Geophysical Research Letters researchers have looked ahead to the year 2100 to show how ice loss will continue to add to rising sea levels. Scientists have known for some time that sea level rise around the globe will not be uniform, but in this study the team of ice2sea researchers show in great detail the global pattern of sea-level rise that would result from two scenarios of ice-loss from glaciers and ice sheets.

The team, from Italy's University of Urbino and the UK's University of Bristol, found that ice melt from glaciers, and the Greenland and Antarctic ice sheets, is likely to be of critical importance to regional sea-level change in the Equatorial Pacific Ocean where the sea level rise would be greater than the average increase across the globe. This will affect in particular, Western Australia, Oceania and the small atolls and islands in this region, including Hawaii.

The study focussed on three effects that lead to global mean sea-level rise being unequally distributed around the world. Firstly, land is subsiding and emerging due to a massive loss of ice at the end of the last ice age 10,000 years ago when billions of tons of ice covering parts of North America and Europe melted. This caused a major redistribution of mass on the Earth, but the crust responds to such changes so slowly that it is still deforming. Secondly, the warming of the oceans leads to a change in the distribution of water across the globe. Thirdly the sheer mass of water held in ice at the frozen continents like Antarctica and Greenland exerts a gravitational pull on the surrounding liquid water, pulling in enormous amounts of water and raising the sea-level close to those continents. As the ice melts its pull decreases and the water previously attracted rushes away to be redistributed around the globe.

Co-author Professor Giorgio Spada says, "In the paper we are successful in defining the patterns, known as sea level fingerprints, which affect sea levels. "This is paramount for assessing the risk due to inundation in low-lying, densely populated areas. The most vulnerable areas are those where the effects combine to give the sea-level rise that is significantly higher than the global average."....

From NASA, the first flight of Operation Ice Bridge’s Antarctic campaign flew Oct. 16, 2009, along the Amundsen Coast. The aircraft’s downward-looking Digital Mapping System camera captured images of sea ice from an altitude of at least 20,000 feet.

Thawing of permafrost expected to cause significant additional global warming, not yet accounted for in climate predictions

UN Environment Programme News Centre:  Permafrost covering almost a quarter of the northern hemisphere contains 1,700 gigatonnes of carbon, twice that currently in the atmosphere, and could significantly amplify global warming should thawing accelerate as expected, according to a new report released today by the UN Environment Programme (UNEP). Warming permafrost can also radically change ecosystems and cause costly infrastructural damage due to increasingly unstable ground, the report says.

"Policy Implications of Warming Permafrost" seeks to highlight the potential hazards of carbon dioxide and methane emissions from warming permafrost, which have not thus far been included in climate-prediction modelling. The science on the potential impacts of warming permafrost has only begun to enter the mainstream in the last few years, and as a truly "emerging issue" could not have been included in climate change modelling to date. The report recommends a special IPCC assessment on permafrost and the creation of national monitoring networks and adaptation plans as key steps to deal with potential impacts of this significant source of emissions, which may become a major factor in global warming.

"Permafrost is one of the keys to the planet's future because it contains large stores of frozen organic matter that, if thawed and released into the atmosphere, would amplify current global warming and propel us to a warmer world," said UN Under-Secretary General and UNEP Executive Director Achim Steiner.

"Its potential impact on the climate, ecosystems and infrastructure has been neglected for too long," he added. "This report seeks to communicate to climate-treaty negotiators, policy makers and the general public the implications of continuing to ignore the challenges of warming permafrost."

...Should the active layer increase in thickness due to warming, huge quantities of organic matter stored in the frozen soil would begin to thaw and decay, releasing large amounts of CO₂  and methane into the atmosphere....

A scientist standing in front of an ice-rich permafrost exposure on the coast of Herschel Island, Yukon Territory (photo: Michael Fritz, from the UNEP website).

Melting glaciers raise sea level

Terra Daily via SPX: Anthropogenic climate change leads to melting glaciers and rising sea level. Between 1902 and 2009, melting glaciers contributed 11 cm to sea level rise. They were therefore the most important cause of sea level rise. This is the result of a new assessment by scientists of the University of Innsbruck. They numerically modeled the changes of each of the world's 300 000 glaciers.

Until 2100, glaciers could lead to an additional 22 cm of sea level rise. Since 1900 the global sea level has risen by approximately 20 cm. Melting glaciers are one of the causes - along with warming and thereby expanding sea water, melting Greenland and Antarctic ice sheets, and changing terrestrial water storage in dammed lakes and groundwater reservoirs.

A team of scientists at the University of Innsbruck has now assessed the contribution of melting glaciers to sea level rise during the 20th century. They numerically modeled each of the world's roughly 300 000 glaciers and used thousands of on-site measurements to validate the model results.

"These calculations show that between 1902 and 2009, glaciers contributed about 11 cm to sea level rise", says Dr. Ben Marzeion from the Institute for Meteorology and Geophysics. "This means they were the most important cause of sea level change."

Surprisingly, melt rates were more or less constant over time: While temperatures during the first decades of the 20th century were considerably lower, glaciers were larger and extended into lower and thus warmer areas. Additionally, brief but strong warm episodes in the Arctic led to strong glacier retreat in the Arctic in the 1930s and 1950s....

Fiescher Glacier, Valais, Alps of Switzerland, from Snapshots Of The Past, Wikimedia Commons via Flickr, under the Creative Commons Attribution-Share Alike 2.0 Generic license.

Why Antarctic sea ice cover has increased under the effects of climate change

Science Daily: The first direct evidence that marked changes to Antarctic sea ice drift have occurred over the last 20 years, in response to changing winds, is published this week in the journal Nature Geoscience. Scientists from NERC's British Antarctic Survey (BAS) and NASA's Jet Propulsion Laboratory (JPL), Pasadena California explain why, unlike the dramatic losses reported in the Arctic, the Antarctic sea ice cover has increased under the effects of climate change.

Maps created by JPL using over 5 million individual daily ice motion measurements captured over a period of 19 years by four US Defense Meteorological satellites show, for the first time, the long-term changes in sea ice drift around Antarctica.

Lead author, Dr Paul Holland of BAS says: "Until now these changes in ice drift were only speculated upon, using computer models of Antarctic winds. This study of direct satellite observations shows the complexity of climate change. The total Antarctic sea-ice cover is increasing slowly, but individual regions are actually experiencing much larger gains and losses that are almost offsetting each other overall. We now know that these regional changes are caused by changes in the winds, which in turn affect the ice cover through changes in both ice drift and air temperature. The changes in ice drift also suggest large changes in the ocean surrounding Antarctica, which is very sensitive to the cold and salty water produced by sea-ice growth.

"Sea ice is constantly on the move; around Antarctica the ice is blown away from the continent by strong northward winds. Since 1992 this ice drift has changed. In some areas the export of ice away from Antarctica has doubled, while in others it has decreased significantly."

...The new research also helps explain why observed changes in the amount of sea-ice cover are so different in the two Polar Regions. The Arctic has experienced dramatic ice losses in recent decades while the overall ice extent in the Antarctic has increased slightly. However, this small Antarctic increase is actually the result of much larger regional increases and decreases, which are now shown to be caused by wind-driven changes. In places, increased northward winds have caused the sea-ice cover to expand outwards from Antarctica. The Arctic Ocean is surrounded by land, so changed winds cannot cause Arctic ice to expand in the same way....

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

Ice sheet retreat controlled by the landscape

India Education Diary: A UK team led by Durham University has found that the geometry of channels beneath the ice can be a strong control on ice behaviour, temporarily hiding the signals of retreat. The findings, which provide the first simulation of past ice-sheet retreat and collapse over a ten-thousand- year period in Antarctica, shed new light on what makes ice stable or unstable and will help refine predictions of future ice extent and global sea-level rise, the researchers say.

The International Panel on Climate Change (IPCC) has stated that one of the main challenges in predicting future sea-level rise is to quantify and model the interactions between evolving ice sheets, oceans, sea level and climate. Significant efforts have been made over the last decade to develop computer models and collect data in order to reduce uncertainties and understand the potential impacts under scenarios of future climate change.

The results of the new research from Durham University, the University of Sheffield, the University of Cambridge, and the British Antarctic Survey are published in the journal Nature Geoscience. Lead author Dr Stewart Jamieson, a glaciologist at the Department of Geography, Durham University, said: “Our research shows that the physical shape of the channels is a more important factor in controlling ice stability than was previously realised. Channel width can have a major effect on ice flow, and determines how fast retreat, and therefore sea-level rise, can happen.

Although climatic and oceanic changes are crucial drivers of ice loss, the research shows that the landscape below the ice strongly controls the speed of any retreat. Dr Jamieson said: "Our results suggest that during an overall phase of retreat an ice stream can appear almost stable when in fact, in the longer-term, the opposite may be the case. Getting a clearer picture of the landscape beneath the ice is crucial if future predictions of change in the ice-sheets and sea level are to be improved.”...

Marine-based ice streams are the fast flowing arteries of ice sheets, draining approximately 90 per cent of the ice that reaches the sea. They flow through large channels where the ice can move thousands of metres in a year. According to the scientists, the unpredictable nature of ice streams makes forecasting ice-sheet retreat extremely difficult. If ice streams speed up they can cause sea level to rise....

Located just 600 miles (970 kilometers) from the North Pole, Franz Josef Land is perpetually coated with ice. Glaciers cover roughly 85 percent of the archipelago’s land masses, and sea ice floats in the channels between islands even in the summertime. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA’s Terra satellite observed the islands of central Franz Josef Land on August 16 and 19, 2011. (Another sensor on Terra captured a wider view on August 17, 2011.)

Past periodic warmth in arctic may be related to melting Antarctic ice sheets

UMassAmherst: First analyses of the longest sediment core ever collected on land in the Arctic, published this week inScience, provide dramatic, “astonishing” documentation that intense warm intervals, warmer than scientists thought possible, occurred there over the past 2.8 million years.

Further, these extreme inter-glacial warm periods correspond closely with times when parts of Antarctica were ice-free and also warm, suggesting strong inter-hemispheric climate connectivity, say the project’s three co-chief scientists. The Polar Regions are much more vulnerable to change than once believed, they add. The team was led by Martin Melles of Germany’s University of Cologne, Julie Brigham-Grette of the University of Massachusetts Amherst and Pavel Minyuk of Russia’s Northeast Interdisciplinary Scientific Research Institute in Magadan.

Brigham-Grette, the lead U.S. scientist says, “What we see is astonishing. We had no idea that we’d find this. It’s astonishing to see so many intervals when the Arctic was really warm, enough so forests were growing where today we see tundra and permafrost. And the intensity of warming is completely unexpected. The other astounding thing is that we were able to determine that during many times when the West Antarctic ice sheet disappeared, we see a corresponding warm period following very quickly in the Arctic. Arctic warm periods cluster with periods when the Western Antarctic ice sheet is gone.”
          
Data reported by Melles, Brigham-Grette, Minyuk and colleagues come from analyzing sediment cores collected in 2009 from under ice-covered Lake El’gygytgyn in the northeast Russian Arctic. “Lake E” was formed 3.6 million years ago when a huge meteorite hit the Earth and blasted out an 11-mile (18 km) wide crater. It has been collecting layers of sediment ever since. Luckily, it is located in one of the few areas in the Arctic not eroded by continental glaciers, leaving the thick sediment record remarkably undisturbed and continuous. Cores from Lake E reach back in geologic time nearly 30 times farther than Greenland ice cores covering the past 110,000 years....

I assume this is a picture of Martin Melles and Julie Brigham-Grette. From the UMassAmherst website

Arctic sea-ice loss didn't happen by chance

Max Planck Institute for Meteorology (Munich): The ongoing rapid retreat of Arctic sea ice is often interpreted as the canary in the mine for anthropogenic climate change. In a new study, scientists have now systematically examined the validity of this claim. They find that neither natural fluctuations nor self-acceleration can explain the observed Arctic sea-ice retreat. Instead, the recent evolution of Arctic sea ice shows a strong, physically plausible correlation with the increasing greenhouse gas concentration. For Antarctic sea ice, no such link is found - for a good reason.

When scientists try to attribute some observed climatic change to a specific forcing, they usually use complex climate models. The scientists at Germany's Max Planck Institute for Meteorology (MPI-M), however, decided on a different strategy as they set out to identify the main driver for the observed sea-ice loss in the Arctic. Dirk Notz, lead author of the study that was now published in the journal Geophysical Research Letters [1], explains why: "Sea ice is so thin that it reacts very sensitive to the large natural fluctuations of weather and climate that prevail in the Arctic. Because these fluctuations are inherently chaotic, their specific timing cannot be reproduced by standard climate models. Such models therefore aren't necessarily the best tool to examine if natural fluctuations did cause the observed sea-ice loss."

The scientists instead used a historical record that described the natural variations of sea-ice extent between the early 1950s and late 1970s. These natural fluctuations were then compared to the magnitude of fluctuations of the Arctic sea-ice cover as measured from satellites since the late 1970s. From such comparison, the scientists found only a minute chance that the recently observed extreme sea-ice minima simply happened by chance - and they could exclude self acceleration as the main driver for the observed sea-ice retreat. "Whenever we had a strong sea-ice loss from one year to the next, the ice cover always recovered somewhat in the following year," explains Dirk Notz. This would not be the case if the sea-ice retreat were indeed self-accelerating.

Jochem Marotzke, Director at MPI-M and co-author of the study, describes what the scientists did next: "Having excluded natural fluctuations and self acceleration as the main driver for the sea-ice retreat, it was clear to us that some external driver was responsible for the observed sea-ice decline. We therefore set out to find an external driver that showed a physically plausible relationship with the observed sea-ice retreat." The scientists examined, for example, the strength of solar radiation. "Here, a physically plausible link to the observed sea-ice retreat can only be established if solar radiation had increased in recent years." However, solar radiation has slightly decreased in the past decades. Its fluctuations are therefore very unlikely to be the main driver of the observed sea ice loss. The scientists could not find a plausible link to changes in prevailing wind patterns, volcanic eruptions, oceanic heat transport, or cosmic rays, either.

"In the end, only the increase in greenhouse gas concentration showed a physically plausible link with the observed sea-ice retreat. We expect a decreasing sea-ice cover for increasing greenhouse gas concentration, which is exactly what is observed," Notz explains. The physical link between greenhouse gas concentration and sea ice is quite straightforward, he adds: "Greenhouse gases increase the downwelling thermal radiation. This radiation, in turn, is the major player in the heat budget of Arctic sea ice."

In the Antarctic, the situation is different. Here, the sea-ice cover is slightly increasing. This increase is clearly incompatible with greenhouse gas concentration being the main driver for the sea-ice evolution down South. The major reason for this discrepancy lies in the different land-mass distributions, the scientists find. In the Arctic Ocean, the ice is virtually locked by the surrounding land masses, and its extent is primarily governed by its melting and freezing. Therefore, greenhouse gases play such an important role up in the high North. In the Antarctic, by contrast, the sea ice is free to drift around in the open Southern Ocean. Hence, the ice extent there is primarily governed by the prevailing wind patterns. "Our results show that greenhouse gas concentration is currently not a major driver for sea-ice extent in the Southern Ocean, where winds and currents clearly are more important," explains Marotzke. "In the land-locked Arctic Ocean, however, greenhouse gas concentration appears to play the dominating role for the observed sea-ice evolution"...

Brent Glacier (Osborn Range), Ellesmere Island, Nunavut, Canada, flowing down to Tanquary Fiord; opposite side: Mount Kennedy Icecap. Yet another superb shot by Ansgar Walk, under the Creative Commons Attribution-Share Alike 3.0 Unported license

Antarctic ice melting from warm water below

Seth Borenstein in Dallas News.com via the AP: 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 23 feet 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 Wednesday 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....

Photo of an Antarctic iceberg by Georges Nijs, Wikimedia Commons via Flickr, under the Creative Commons Attribution 2.0 Generic license