Antarctica and the Arctic
03 Apr 2013:
Arctic Air Pressure System
Causes Unusual March Temperatures
A pronounced shift in Arctic air pressure systems has triggered unusually cold temperatures across North America, Europe, and northern Asia, while allowing a
flood of warmer air into Greenland and northeastern Canada, according to NASA. In recent weeks, the so-called Arctic Oscillation (AO) index — which tracks the relative pressure differential between the Arctic and mid-latitudes — dropped to the fifth-lowest reading ever recorded, NASA scientists said
. When the AO reaches this “negative” phase, scientists say, the pressure gradient between the Arctic and mid-latitudes weakens, allowing Arctic air to stream south. This NASA graphic
depicts unusual land surface temperatures across the Northern Hemisphere, with Europe, Russia, and the U.S. experiencing temperatures as high as 5 to 15 degrees C below normal, while temperatures in Greenland were as high as 15 degrees C above normal. Britain recorded its fourth-coldest March since 1962, Germany experienced its coldest March since 1883, and Moscow had its coldest March since the 1950s.
11 Mar 2013:
New Arctic Survey Shows
Major Advances of Vegetation to North
Declining snow and ice coverage in the northern latitudes and rising temperatures have triggered a significant increase in vegetation
across large swaths of the Arctic, with some circumpolar regions seeing the
Click to enlarge
Goddard Space Flight Center
Vegetation shift in northern latitudes
type of plant growth that just a few decades ago occurred hundreds of miles to the south, according to a new study. In a comprehensive analysis of ground and satellite-based data, a team of scientists found that across a region covering more than 9 million square kilometers — roughly equal to the size of the U.S. — vegetation is growing more vigorously and spreading north. The study, published in the journal Nature Climate Change
, said that since the early 1980s, the kind of vegetation that was once found at 57 degrees north — typified by tall shrubs and trees — is now spreading into former regions of tundra as far as 64 degrees north. The paper said that 17 climate model simulations suggested that bv the end of this century rising temperatures could lead to northward shifts of vegetation of more than 20 degrees latitude compared with the period 1951 to 1980.
07 Jan 2013:
New Arctic Experiments Yield
Insights Into State of Permafrost Carbon
A team of U.S. researchers recently deployed a suite of technologies in the Arctic tundra that they say will provide a better understanding of the carbon contained in permafrost soils
and how much is likely to be released as the planet warms. At an experimental plot near Barrow, Alaska, scientists are using several techniques, from ground-penetrating radar systems dragged on sleds to airborne instruments that measure micro-topography, to better understand how different layers of permafrost are interrelated and react as the soil warms. Ultimately, the scientists say, the research will provide critical information on how these permafrost systems change over time, and how much of their vast stores of carbon might be released. “This approach allows us to sample over large spatial regions with minimal disturbance to the ecosystem — two important criteria when it comes to studying the vast and delicate Arctic landscape,” said Susan Hubbard, a geophysicist at the Lawrence Berkeley National Laboratory.
30 Nov 2012:
Accelerated Ice Sheet Melt
At Both Poles Documented in Study
The ice sheets of Greenland and Antarctica are losing three to five times as much ice annually
as they did two decades ago, a rate of ice loss equivalent to sea level rise of 0.04 inches per year, according to a new study supported by NASA and the European Space Agency
. In an analysis of data from 10 different satellite missions, the international team of 47 experts calculated that the rate of melt in Greenland is five times greater than during the mid-1990s. While the new findings on total ice loss fall within the range produced by the Intergovernmental Panel on Climate Change in 2007, the new study provides a more definitive assessment that Antarctica’s ice sheets, like Greenland’s, are shrinking. Combined, these ice sheets have added .44 inches (11.1 millimeters) to sea levels worldwide since 1992, accounting for about 20 percent of total sea-level rise during that period. “This will give the wider climate science community greater confidence in ice losses and lead to improved predictions of future sea-level rise,” said Andrew Shepherd, a scientist at the University of Leeds and co-leader of the study, which is published in the journal Science
26 Nov 2012:
Snails in Southern Ocean
Showing Effects of Ocean Acidification
The shells of some sea snails in the Southern Ocean are already dissolving as a result of ocean acidification
, according to a new study. In an analysis of free-swimming pteperods collected from Antarctic waters in 2008, scientists found that the outer layers of the animals’ shells showed signs of unusual corrosion, potential evidence that ocean acidification caused by excess carbon dioxide in the atmosphere may already be disturbing vulnerable marine species. Laboratory tests have shown that acidic water threatens many invertebrate marine species, such as clams and corals, since it hinders their ability to grow shells and exoskeletons. The most vulnerable species are those, like pteropods, that build their shells from aragonite, a form of calcium carbonate that is sensitive to increased acidity, according to the study, published in Nature Geoscience
13 Nov 2012:
Gains in Antarctic Sea Ice Cover
Triggered by Wind Shifts, Study Says
Scientists say they have the first direct evidence that changes in Antarctic sea ice drift caused by changing winds have produced an increase in Antarctic sea ice
cover over the last two decades even as historic declines have been observed in the Arctic. Using more than 5 million measurements of daily sea ice movement collected over 19 years, researchers from NASA and the British Antarctic Survey detected long-term changes in sea ice drift
, a phenomenon that has caused overall increases in sea ice cover. While sea ice around Antarctica is constantly being blown away from the continent by northerly winds, the rate of ice movement in some areas has doubled since 1992, causing total sea ice, which reflects heat from the sun, to expand out from Antarctica, according to their findings, which were published in Nature Geoscience
. “The Antarctic sea ice cover interacts with the global climate system very differently than that of the Arctic, and these results highlight the sensitivity of the Antarctic ice coverage to changes in the strength of the winds around the continent,” said Ron Kwok of NASA’s Jet Propulsion Laboratory.
05 Nov 2012:
China and Russia Block
Proposal to Protect Antarctic Waters
International talks to protect large areas of the Southern Ocean surrounding Antarctica collapsed last week
after several nations, including China, blocked the proposal over concerns about fishing access, according to reports. Representatives from 25 member states — including China, Russia, the U.S., the European Union — gathered in Australia to negotiate plans that would have protected approximately 4 million square kilometers in the Southern Ocean, including provisions that would have banned industrial fishing operations. Some regions would have also been set aside for scientific research into the effects of climate change on polar ecosystems. According to The Australian newspaper
, China and Russia were among the nations that rejected the plans. Alex Rogers, a conservation biologist at the University of Oxford, told Nature
that the stalled talks reflect a wider “global dichotomy” about how to manage marine resources, with some states looking to impose greater conservation and management policies and others targeting increased exploitation. “Time really is running out on these issues,” he said. “If we don’t get protection in place now, exploitation of these systems will increase.”
02 Nov 2012:
Sea-Level Rise Projections
Ignored Critical Feedbacks, Researcher Says
A U.S. researcher says projected sea-level rise over the next century has been underestimated because current models fail to consider several critical feedbacks
that might accelerate rising seas in the coming decades. While the 2007 report of the Intergovernmental Panel on Climate Change predicted that global sea levels could rise 0.2 to 0.5 meters by 2100, current projections suggest that seas could rise a meter or more. One of the factors ignored by earlier models, says University of Colorado geologist Bill Hay, is the influx of warm, briny ocean water into the Arctic that occurs when melting fresh water is released, a phenomenon he says acts as a sort of “heat pump” in the Arctic, adding more ice-free waters, which then absorb more solar energy. According to Hay, who will present his findings at the annual meeting of The Geological Society of America, another factor that was ignored is the potential melting of large ice sheets in Greenland and western Antarctica. A third feedback, he said, is the vast amounts of groundwater being removed to address humankind’s surging water needs, much of which ultimately ends up in the oceans.
Photo Gallery: A Quest to Document
The Earth’s Disappearing Glaciers
Since 2007, photographer James Balog has deployed dozens of time-lapse cameras on four continents to chronicle one of the starkest examples of global warming — the rapid melting of the world’s glaciers. That project, known as the Extreme Ice Survey and carried out in collaboration with leading glaciologists, is captured in an e360 gallery of his photos
selected from his new book, Ice: Portraits of Vanishing Glaciers
. In an accompanying interview with Yale Environment 360
, Balog discusses what has driven him to devote so much of his life to “preserving the visual memory” of a vanishing landscape. “We’re telling a story about what’s happening right here, right now, as a consequence of human action,” he says. “I think it’s vital to keep telling that story.”
View a photo gallery
25 Oct 2012:
Rapid Thinning of Glaciers
Seen After Collapse of Antarctic Ice Shelf
NASA has released satellite photos that vividly depict the precipitous thinning and retreat of two Antarctic glaciers
following the disintegration of the Larsen B Ice Shelf. That ice shelf — which floated on top of the
Weddell Sea and once was the size of Connecticut — collapsed in 2002 after several years of warm summer temperatures. The Larsen B had acted as a buttress slowing the flow of numerous glaciers into the sea. The NASA satellite images, taken in 2002 and in 2012, demonsrate how swiftly the Green and Hektoria glaciers behind the ice shelf surged into the ocean. The 2002 photo shows the glaciers covering much of nearby mountain ridges and the termini, or end points, of the glaciers are not visible. The 2012 photo shows that the thinning glaciers now cover considerably less of surrounding mountain ridges and the termini of both glaciers are visible. The 2012 image also shows the numerous crevasses that have formed as the glaciers have thinned.
24 Oct 2012:
Plastic Waste Increasing
On Remote Arctic Seabed, Cameras Reveal
Deep-sea cameras deployed to monitor biodiversity on the Arctic seabed have documented a significant rise in the amount of plastic waste and other litter
on the remote sea floors of the Far North, according to a new study. While looking at many thousands of seabed photos taken in 2011 between Greenland and the Norwegian island of Spitzbergen, deep-sea expert Melanie Bergmann of the Alfred Wegener Institute for Polar and Marine Research was struck by the number showing plastic waste. In a detailed analysis of the photographs — which are taken every 30 seconds by a deep-sea observatory reaching depths of 2,500 meters — Bergmann and her colleagues found that while plastic waste was seen in only one percent of photographs taken in 2002, that number had jumped to 2 percent in 2011. Two percent may not seem like a high occurrence, Bergmann said, but the quantities observed in this remote Arctic region were greater than recorded in a deep-sea canyon near Lisbon, Portugal. According to the study, published in the journal Marine Pollution Bulletin
, about 70 percent of the plastic litter had come in contact with deep-sea organisms.
22 Oct 2012:
Shifting Arctic Wind Patterns
May Cause Increased Melt, Study Says
U.S. scientists say unusual air pressure patterns over the Arctic during the month of June in recent years have altered wind patterns in the region, funneling warmer air into the Arctic and contributing to record low Arctic
Air pressure over the Arctic, 2007-2012.
summer sea ice extent from 2007 to 2012. Writing in the journal Geophysical Research Letters
, a team of researchers illustrated how the formation of two unusual high pressure areas over the North American Arctic and Greenland disrupted the normal westerly flow of winds, creating “blocking highs” that led to an unusually strong flow of warm southerly air. That sent more warm air into the central Arctic and Greenland
, which may have been a factor in unusually dramatic summer thaws beginning in 2007. While it is unclear why these unusual patterns of high pressure have occurred in each of the last six Junes, NOAA researcher James Overland believes it may be related to declining snow cover in the Canadian Arctic in recent years. “We don’t know that part of the story yet,” he said.
Solar Geoengineering Projects
Could Be More Effective on Regional Scale
A new modeling study by several geoengineering experts suggests that injecting aerosols into the atmosphere to block more of the sun’s energy and reduce temperatures could be most effective when done on a region-by-region basis
. The study, published in the journal Nature Climate Change
, said that injecting aerosols over the Arctic Ocean in summer, for example, might be an effective way to not only slow the rapid loss of Arctic sea ice but possibly even restore it to pre-industrial levels. The researchers — led by David Keith of Harvard University, Ken Caldeira of the Carnegie Institution for Science, and Douglas McMartin of the California Institute of Technology — cautioned that their models were rough and that bringing about changes in regional climate patterns can have global effects
. But they said the study shows the need for more detailed research into how solar geoengineering techniques could be used to slow or reverse the effects of climate change on rapidly warming areas. “Our research goes a step beyond the one-size-fits-all approach to explore how careful tailoring of solar geoengineering can reduce possible inequalities and risks,” said Keith.
27 Sep 2012:
Are Warmer than Any Time in 1,800 years
Summer temperatures on the Norwegian archipelago of Svalbard in the High Arctic are now higher than during any time over the last 1,800 years
, including a period of higher temperatures in the northern hemisphere known as the Medieval Warm Period
, according to a new study. In an analysis of algae buried in deep lake sediments, a team of scientists calculated that summer temperatures in Svalbard since 1987 have been 2 to 2.5 degrees Celsius (3.6 to 4.5 degrees F) warmer than during the Medieval Warm Period, which lasted from roughly 950 to 1250 AD. The Medieval Warm Period is often cited by climate change skeptics as proof that the planet has experienced periods of high temperatures in recent centuries unrelated to the burning of fossil fuels. The algae, which make more unsaturated fats in colder periods and more saturated fats in warmer periods, reveal critical clues about past climates. Scientists were able to date the lake specimens by analyzing grains of glass emitted by a series of well-known Icelandic volcanoes that left unique chemical time markers. The study is published in the journal Geology
20 Sep 2012:
Arctic Sea Ice Extent
Reaches a Dramatic New Low
As the summer melt season ends, Arctic sea ice extent has now fallen to an exceptionally low level
, covering an area only half the size of the 1979 to 2000 average. The
Colorado-based National Snow and Ice Data Center (NSIDC) reported that as of September 16, Arctic sea ice extent was only 1.32 million square miles, which is 18 percent below the previous record low of 1.61 million square miles, set in September 2007. “We are now in uncharted territory,” said NSIDC director Mark Serreze. “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.” A key reason for the precipitous decline of sea ice extent is that Arctic Ocean ice has become so thin after years of rapidly rising temperatures in the region, with thick, multi-year ice being replaced by thin, year-old ice that swiftly melts in summer.
28 Aug 2012:
Arctic Ice Reaches Record Low
The extent of ice covering the Arctic Ocean has reached a new record low
and will likely continue to retreat until mid-September, when re-freezing begins to occur, according to satellite observations. NASA and the
U.S.-funded National Snow and Ice Data Center (NSIDC) reported that sea ice extent fell in the past few days to 1.58 million square miles (4.1 million square kilometers), breaking by 27,000 square miles the previous record low extent, set in September 2007. Summer sea ice extent has declined by more than 40 percent since satellites began tracking it in 1979, and sea ice now covers less than 30 percent of the Arctic Ocean.
Sea ice experts say that both the extent and thickness of Arctic summer sea ice has declined so precipitously in the face of rapidly rising temperatures that the Arctic basin appears to be heading for largely ice-free summers within a decade or two. “Parts of the Arctic have become like a giant slushy,” said Walt Meier, a research scientist at the NSIDC. The disappearing sea ice is creating ever-larger areas of dark, heat-absorbing waters, which is further increasing temperatures in the Arctic and hastening the melting of Greenland’s massive ice sheets.
01 Aug 2012:
New Whale Recordings Hint
at Bowhead Recovery off Greenland
A wide array of whale songs recorded in the icy waters off Greenland indicates that populations of the endangered bowhead whale, nearly hunted to extinction in the last two centuries, may be experiencing a rebound
A bowhead whale
collecting 2,144 hours of audio recordings in the waters between Greenland and Norway from September 2008 to July 2009, an international team of scientists detected a surprising variety and duration of whale songs. Not only did the recordings yield roughly five months of near-continuous singing, but they revealed more than 60 unique “songs,” most likely belonging to individual whales, according a study published in the journal Endangered Species Research
. Since scientists believe male bowheads sing during mating season — and because most whale species are believed to sing the same song throughout their lives — the findings could suggest that bowhead populations in that area exceed 100 whales, far more than previously believed; only 40 bowhead sightings have been reported in that area since the 1970s, according to the researchers.
Listen to the bowheads’ song
Unusual Number of Grizzly and
Hybrid Bears Spotted in High Arctic
Two Canadian biologists have reported sighting a handful of grizzly bears and hybrid grizzly/polar bears at unusually high latitudes in the Arctic, indicating that the interbreeding of the two bear species is becoming more common as the climate warms and grizzlies venture
Photo courtesy of Jodie Pongracz
A hybrid polar/grizzly bear in the Canadian Arctic
farther north. The sightings of three grizzly bears and two hybrid bears, made in late April and May by biologists from the University of Alberta, represent an unprecedented cluster of these animals at such high latitudes. The biologists even took DNA samples from a grizzly bear at 74 degrees North latitude. Scientists suggested that some grizzly bears may be leaving the Canadian Arctic mainland and traveling roughly 400 miles over sea ice as they pursue a caribou herd that annually migrates over ice from the mainland to Victoria Island in the High Arctic. Unable to get back because of rapidly melting ice, some of these grizzly bears have evidently managed to adapt to life in the polar bear’s world, eating seals as they overwinter and mating with polar bears.
25 Jul 2012:
Entire Greenland Ice Sheet
Experiences Significant Surface Melting
New NASA satellite images show that the surface of virtually the entire ice sheet covering Greenland experienced melting in mid-July
, a phenomenon not
seen in three decades of satellite observations. Temperatures rose so high that ice on the Greenland’s highest peak, Summit Station, turned to slush, NASA said. Until the severe melting earlier this month, the greatest extent of surface melting observed by satellites over the past three decades covered about 55 percent of the ice sheet; on July 12, 97 percent of the ice sheet experienced surface melting. Ice cores from Greenland show that such melting events have occurred roughly every 150 years, but Greenland’s ice sheet has been experiencing rapid melting in the past decade and if another major melting event occurred within the next 10 years it could disrupt the stability of the ice sheet
, said Thomas Mote, a climatologist at the University of Georgia. “When we see melt in places that we haven’t seen before, at least in a long period of time, it makes you sit up and ask what’s happening,” NASA scientist Waleed Abdalati told the BBC
24 Jul 2012:
Evolution of Polar Bear
Followed Changes in Climate, Study Says
An analysis of sequenced polar bear genomes provides new insights into how climate change and interbreeding with brown bears led to the evolution of the modern-day polar bear
. In an analysis of the nuclear genomes of 28
Photo courtesy of Andrew Derocher
brown, black, and polar bears, an international team of researchers found evidence that polar bear populations fluctuated with climate shifts over the last million years, with populations increasing during cooler periods and declining during periods of warmer temperatures. Their findings also suggest that during periods of glacial retreat, polar bears came into greater contact with brown bears as their ranges overlapped. “Maybe we’re seeing a hint that in really warm times, polar bears changed their life style and came into contact, and indeed interbred, with brown bears,” said Stephan Schuster, a scientist at Pennsylvania State University and co-lead author of the study, published in the Proceedings of the National Academy of Sciences
. While earlier research indicated that polar bears have only existed for about 600,000 years, the new research suggests that the polar bear may have evolved into a distinct species 4 to 5 million years ago.
19 Jul 2012:
Shows Ability to Trap CO2 in Ocean
An eight-year German research effort has shown that under the right conditions seeding the ocean with iron can trigger phytoplankton blooms that suck carbon out of the air and trap it deep in the ocean,
a potentially important breakthrough in the nascent field of climate geoengineering. Reporting in the journal Nature
, scientists from the Alfred Wegener Institute for Polar and Marine Research said that adding 14 tons of iron sulfate to the Southern Ocean near Antarctica resulted in a significant phytoplankton bloom extending more than 300 feet deep. That bloom consisted of large masses of algae, mainly composed of diatoms, which absorbed carbon dioxide from the atmosphere. More than 50 percent of the carbon-rich algae then sunk to a depth of more than 3,000 feet, where it is likely to be trapped for centuries. The German research team conducted the iron-seeding experiment in 2004 and then spent eight years analyzing the data. Previous iron-seeding experiments have had difficulty tracking the path of CO2 pulled out of the atmosphere because of swirling currents and other complications. But the Wegener team said its experiment had succeeded because scientists found a 40-mile-wide column of water that was isolated from other ocean currents.
08 Jun 2012:
Major NASA Discovery Finds
Phytoplankton Blooms Under Arctic Ice
For the first time, scientists have discovered extensive blooms of phytoplankton under Arctic Ocean ice,
contradicting the widely held conviction that such blooms could not occur under sea ice that blocked the sun's rays from triggering the blooms. Scientists on a NASA-sponsored expedition to the Arctic Ocean say the blooms are likely related to the rapid thinning of Arctic sea ice, which allows sunlight to penetrate the ice and trigger blooms. Working on a U.S. Coast Guard icebreaker last summer in the Beaufort and Chukchi seas off Alaska, the scientists discovered massive blooms that extended from the sea-ice edge to 72 miles inside the pack ice. The blooms did not occur under thick ice, but rather under melt ponds and nearly translucent melting ice. “This is like finding the Amazon rainforest in the middle of the Mojave Desert,” said Paula Bontempi, NASA’s ocean biology and biogeochemistry program manager. The research, published in Science
, sheds new light on how the Arctic Ocean ecosystem may be reacting to a rapidly warming climate,
affecting marine life from phytoplankton at the base of the food chain to gray whales at the top.
31 May 2012:
C02 Milestone Reached
As Levels Hit 400 PPM Across Arctic
For the first time in at least 800,000 years, atmospheric concentrations of carbon dioxide have crossed the threshold of 400 parts per million (ppm)
, with stations across the Arctic recording these record levels, the Associated Press
reports. Global concentrations have hit 395 ppm, but in recent months levels of carbon dioxide in the atmosphere surpassed 400 ppm in the Arctic because of the lack of CO2-absorbing vegetation in the Far North in winter and spring. Pre-industrial levels of CO2 were about 280 ppm, and numerous scientists said that hitting the 400 ppm threshold was a worrisome sign that industrial society continues to emit planet-warming greenhouse gases at an alarming rate. Jim Butler, global monitoring director at the National Oceanic and Atmospheric Administration’s Earth System Research Lab in Colorado, called the new high a “troubling milestone.” Levels exceeding 400 ppm have been recorded this spring in Alaska, Greenland, Norway, and Iceland.
22 May 2012:
Rivers are Largest Source
Of Mercury in Arctic Ocean, Study Says
A new study suggests that rivers may be funneling far more toxic mercury into the Arctic Ocean than previously believed, a finding that may portend even greater mercury concentrations in the future as the effects of climate change accelerate the region’s hydrological cycle. Despite the Arctic's remoteness, scientists have long known that mercury levels in Arctic mammals are among the highest on the planet, a factor largely attributed to mercury being deposited in the Arctic Ocean from the air. But according to Harvard scientists
, circumpolar rivers — particularly three Siberian rivers, the Lena, Ob, and Yenisei — may be contributing twice as much mercury as the atmosphere. According to the scientists, mercury levels in the Arctic tend to increase sharply during the spring and summer. Using a sophisticated model of atmospheric and ocean conditions, they concluded the only factor that could explain this spike was increased flow of these rivers as they melt. According to the researchers, more mercury may be entering the river systems as melting permafrost increasingly releases mercury locked in the soil. In addition, mercury is likely coming from runoff from gold, silver, and mercury mines in Siberia. The study is published in Nature Geoscience
21 May 2012:
Methane Sources Found
Bubbling Up from Melting Ice Caps
U.S. scientists report that they have discovered new sources of methane percolating up from underground reservoirs
as glaciers, ice caps, and permafrost melt in the Arctic. University of Alaska researchers, conducting aerial and ground surveys, said they have discovered 150,000 methane seeps in Alaska alone near the margins of retreating glaciers or thawing permafrost. In Greenland, the seeps tended to be concentrated around the margins of ice caps that have been retreating for the past 150 years, the scientists said. Katey M. Walter Anthony, lead author of the study, published in Nature Geoscience
, said these seeps in the earth’s frozen zones, or cryosphere, are not currently a major source of methane emissions. But, she added, “As the cryosphere degrades further, it could be a really big source.” Methane is a far more potent greenhouse gas than carbon dioxide, and researchers are concerned rapid warming of the Arctic could trigger a methane “time bomb
” as thawing permafrost, vegetation, and land ice result in the release of huge quantities of methane.
04 May 2012:
Greenland Glaciers Moving
More Slowly Than Previous Estimates
A new U.S. study says that Greenland’s glaciers are sliding into the sea more slowly than previously estimated
, a finding that may indicate future sea level rise will not be as high as some projected worst-case scenarios. Using satellite data to track changes to 200 outlet glaciers from 2000 to 2011, a team of scientists calculated that Greenland’s glaciers accelerated by an average of 30 percent during the decade — a significant amount but not as rapidly as feared. In an earlier study, scientists calculated that glacial flow would increase by 100 percent between 2000 and 2010, and then stabilize at the higher speed, contributing as much as 19 inches to global sea level rise by the end of the century. According to the new study, published in the journal Science
, the glaciers are expected to continue gaining speed in the coming decades, possibly contributing four inches to sea level rise by 2100. The researchers cautioned, however, that a 10-year study is too short to make any conclusions on long-term behavior.
02 May 2012:
Polar Bears Taking Long Swims
In Absence of Summer Sea Ice, Study Says
A six-year study has found that polar bears are capable of swimming great distances
when foraging for food, an increasingly critical skill as Arctic sea ice declines in summer. Using GPS collars attached to 52 adult females in the southern Beaufort and Chukchi seas from 2004 to 2009, scientists from the U.S. Geological Survey (USGS) found that about a third of the bears — including some with cubs — completed swims greater than 30 miles. Writing in the Canadian Journal of Zoology
, the scientists found that in the case of 50 long-distance swims, the bears traveled an average of 96 miles, swimming from one to 10 days; one bear swam 220 miles. While such stamina will become increasingly important for polar bears as a warming climate makes resting on summer sea ice a less available option, the researchers expressed concern that traveling such great distances takes a greater energy toll on the animals. The study sample was too small to draw conclusions about the fate of entire populations, and it is unclear whether such long swims are a new behavior.
26 Apr 2012:
Warm Ocean Currents Play
Key Role in Melting Antarctic Ice Shelves
Warm ocean currents are melting many of Antarctica’s floating ice shelves from beneath
, which in turn is speeding up the flow of land-based glaciers into the ocean and increasing global sea levels, according to a new study. An international team of scientists, led by researchers from the British Antarctic Survey (BAS), used 4.5 million measurements from a satellite-based laser altimeter that precisely measures the changing thickness of ice shelves. Using those readings and other data, the researchers determined that 20 of 54 ice shelves that flow off the Antarctic continent and float on the Southern Ocean are melting and thinning from below. Most of the 20 ice shelves are in West Antarctica, where air and ocean temperatures have been steadily rising in recent years. Along the western Antarctic Peninsula, eight ice shelves have fully or partially collapsed in the past several decades, allowing inland glaciers to surge into the sea. But the study, published in Nature
, found that even the thinning of ice shelves, without total collapse, speeds up the flow of inland glaciers, increasing global sea levels.
24 Apr 2012:
European Satellite Provides
Precise Data On Arctic Sea Ice Thickness
The European Space Agency’s (ESA) CryoSat satellite is now providing highly accurate data on the thickness and volume of Arctic Ocean ice
. Using a high-resolution
synthetic aperture radar that sends down pulses of microwave energy, the satellite can measure the difference between the top of the ice and water in the cracks, or leads, that separate the floes. By measuring the height of the ice above water, which usually represents only one-eighth of total ice thickness, the satellite can provide data on ice thickness to within 10 to 20 centimeters, or 4 to 8 inches. The CryoSat satellite was launched in 2010, and since then scientists have been validating the measurements against other data from plane-based instruments and direct, on-ice measurements. "We now have a very powerful tool to monitor the changes taking place at the poles,” said Volker Liebig, the ESA’s director of Earth Observation.
12 Apr 2012:
Drilling of Arctic Could Pose
Ecological Risks, Lloyd’s Report Warns
A new report by Lloyd’s of London, the world’s largest specialist insurance market, warns that rapid development of Arctic oil resources threatens to cause huge ecological damage without strict oversight
and appropriate risk management. The report, Arctic Opening: Opportunity and Risk in the High North
, projects that as much as $100 billion ((£63 billion) will be invested in the Arctic region over the next decade as the melting of sea ice opens up vast areas to oil and gas exploration and creates new shipping routes. And while this phenomenon will create significant business opportunities, the report says it is “highly likely” that it will also further disturb ecosystems already stressed by climate change and create risks associated with oil spills, particularly in ice-covered areas. “The resilience of the Arctic’s ecosystems in terms of withstanding risk events is weak, and political sensitivity to a disaster is high,” a summary of the report
on the Lloyd’s Web site says. “As a result, companies operating in the Arctic face significant reputational risk.”