tagged w/ Antarctica
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The amount of ice melting on the Antarctic Peninsula has increased dramatically in recent decades.
Steff Gaulter
Last Modified: 14 Apr 2013 13:20
For the first time, scientists have managed to demonstrate that ten times more ice melts in the summer months on the Antarctic Peninsula now than it did 600 years ago.
The Antarctic Peninsula is the biggest and most prominent peninsula in Antarctica. It consists of a rugged mountain chain, which rises more than 2000 m high.
Unlike the majority of the continent, the ice on the peninsula experiences a degree of melting every summer. Over recent decades the amount of ice which has melted has been increasing.
It has been known for some time that temperatures across the Antarctic Peninsula have risen dramatically. Over the past fifty years there has been an increase of 2.8C, making this the most rapidly warming region in the Southern Hemisphere. This is over five times the global average and comparable to rapidly warming regions of the Arctic.
At the same time, around 25,000 km2 of ice have been lost from ten floating ice shelves on the Antarctic Peninsula. This is particularly significant as it takes a long time to replenish snow and ice in this part of the world.
With under 250 mm of precipitation per year, Antarctica is officially classed as a desert. In fact, some parts of the continent haven’t seen any rain or snow for many years. Across the Antarctic Peninsula, the snow and ice simply melts and refreezes. Currently the ice that is lost to melting far exceeds that which is replenished in a year.
The latest research, a joint project by the Australian National University and the British Antarctic Survery, looks at a 364 m ice core, which was extracted from the northern tip of the peninsula. Visible layers of this tube of ice show where the ice melted, then refroze. By measuring the thickness of the layers and analysing the gases contained in the ice, researchers were able to determine the changes in temperatures in the region over the last 1,000 years.
The ice core demonstrated that the current level of melting was unprecedented in the last 1,000 years, and ten times more than it was 600 years ago.
The climate of Antarctica is hugely complex. Although there are record levels of glacier and ice melting, there also appears to be an increase in the sea ice in the surrounding waters.
Just seven months ago satellites captured images of more ice floating around the continent than at any other time in history.
The increase in sea ice is thought to be caused by the increased amounts of melting ice. This melted ice runs into the sea, but does not mix with the water already in the ocean. Instead the water forms a separate, colder, layer on the surface of the ocean. This can protect sea ice from coming into contact with the warmer seas below and therefore prevent it melting.
It is also thought that a change in wind direction could have increased the extent of sea ice. Winds can both physically moving the ice, and can cause the sea surface to warm or cool. The increase in sea ice is not uniform around the Antarctic coast line, therefore the winds are also likely to have had some effect.
With the complex climate of Antarctica, and the uncertainty of the future of the climate, it is difficult to predict what this latest study means for the continent.
It is believed that the continent will continue to warm rapidly, particularly in summer, increasing the vulnerability of the delicate ecosystem of the continent.
The global significance of this is difficult to assess. However, the warming of the Antarctic Peninsula is amongst the highest seen anywhere on Earth in recent times, and is a reminder of the rationality of climate change that can be expected in the future.The amount of ice melting on the Antarctic Peninsula has increased dramatically in... more
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New research from the Antarctic Peninsula shows that the summer melt season has been getting longer over the last 60 years. Increased summer melting has been linked to the rapid break-up of ice shelves in the area and rising sea level.
The Antarctic Peninsula - a mountainous region extending northwards towards South America - is warming much faster than the rest of Antarctica. Temperatures have risen by up to 3C since the 1950s - three times more than the global average.
This is a result of a strengthening of local westerly winds, causing warmer air from the sea to be pushed up and over the peninsula. In contrast to much of the rest of Antarctica, summer temperatures are high enough for snow to melt.
This summer melting may have important effects. Meltwater may enlarge cracks in floating ice shelves which can contribute to their retreat or collapse. As a result, the speed at which glaciers flow towards the sea will be increased. Also, melting and refreezing causes snow layers to become thinner and more dense, affecting the height of the snow surface above sea level. Scientists need to know this so they can interpret satellite data correctly.
Dr Nick Barrand, who carried out the research while working for the British Antarctic Survey, led an analysis of data from 30 weather stations on the peninsula. "We found a significant increase in the length of the melting season at most of the stations with the longest temperature records" he says. "At one station the average length of the melt season almost doubled between 1948 and 2011."
To build up a more complete picture across the whole peninsula, the team (funded by the European Union's ice2sea programme) also analysed satellite data collected by an instrument called a scatterometer. Using microwave reflections from the ice sheet surface, the scatterometer was able to detect the presence of meltwater.
The team were able to produce maps of how the melt season varied from 1999 to 2009, and showed that several major ice shelf breakup events coincided with longer than usual melt seasons. This supports the theory that enlargement of cracks by meltwater is the main mechanism for ice shelf weakening and collapse.
More at the linkNew research from the Antarctic Peninsula shows that the summer melt season has been... more
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ADHD Rises by Almost 25% in 1 Decade-Snowdrops can fight dementia and lavender may treat hair loss: How medicine’s getting a dose of flower power-Bill Clinton checking out Kelly Clarksons ass during inauguration ceremony-RUSSIAN PROTEST AGAINST ANTI-GAY LAW TURNS VIOLENT-Antarctica takes out its frustration on the children of the 1%-Files show how church hid abuse reports-Hospital nurse arrested for necrophilia-Three volcanoes erupt in Kamchatka Peninsula-U.S. begins transporting French troops, equipment to MaliADHD Rises by Almost 25% in 1 Decade-Snowdrops can fight dementia and lavender may... more
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The growing number of people setting foot on Antarctica is allowing more non-native species to arrive.
An invasive species has the potential to drastically alter Antarctic ecosystems that have been isolated for millions of years, research suggests.
A species of midge was able to release large volumes of nutrients into the soil, changing the way native species had lived and evolved, a UK team found.
They added the species was well-suited to thrive in the extreme conditions.
Details of the research were presented at the British Ecological Society's annual meeting in Birmingham.
A team from the British Antarctic Survey said the invasive species, the non-biting midge Eretmoptera murphyi, effectively removed one of the brakes on the way that the native community had developed.
"In terms of function, their job is litter turnover - they help things decay in the soil - and the population density of this thing in the area where it has been introduced is responsible for more litter turnover than the community that was already there," explained co-presenter of the research Peter Convey, of the British Antarctic Survey.
"So basically it is bringing a function into an ecosystem that is not very active already. In principle, it can be a fundamental change in the way that ecosystem works."
By Mark Kinver
18 December 2012
Continued at linkThe growing number of people setting foot on Antarctica is allowing more non-native... more
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A major new international study reconciles “an ensemble of satellite altimetry, interferometry, and gravimetry data sets” to determine polar ice-sheet ice loss with the highest accuracy to date. The study, “A Reconciled Estimate of Ice-Sheet Mass Balance” (subs. req’d) was published in the journal Science Thursday.
The NASA Jet Propulsion Laboratory news release explains the study’s significance:
snip
“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,” [JPL's Erik] 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.”
More at the linkA major new international study reconciles “an ensemble of satellite altimetry,... more
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Nations fail to agree plan to protect seas around Antarctica -Tax study withdrawn after GOP complaints-Suit: Officer shot boy, 10, with stun gun-U.S. officials: CIA ran Benghazi consulate--Video purports to show rebels’ atrocities
EX-PENN ST. PRESIDENT CHARGED IN SANDUSKY CASENations fail to agree plan to protect seas around Antarctica -Tax study withdrawn... more
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OK, Hippies… These stories keep coming up on my news feeds. Main stream media won’t report them.
These guys are not stupid people they do have some creditability. (More then the US Government or the main stream media.) So you dear reader, decide.OK, Hippies… These stories keep coming up on my news feeds. Main stream media... more
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There are many factors that can speed up or slow down climate caused changes in glaciers and ice sheets. Ice-sheet retreat can halt temporarily even during a long warming phases. A UK team led by Durham University has found that the geometry of channels beneath the ice can be a strong control on ice behavior, temporarily hiding the signals of ice 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 results of the new research from Durham University, the University of Sheffield, the University of Cambridge, and British Antarctic Survey are published this week 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 realized. 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 added: "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."
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 meters 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.
An ice stream is a region of an ice sheet that moves significantly faster than the surrounding ice. Ice streams are a type of glacier. They are significant features of the Antarctic where they account for 10% of the volume of the ice. They are up to 50 km wide, 2 km thick, can stretch for hundreds of kilometers, and account for most of the ice leaving the ice sheet.
The speed of an ice stream can be over 1,000 meters per year, an order of magnitude faster than the surrounding ice. The shear forces at the edge of the ice stream cause deformation and recrystallization of the ice, making it softer, and concentrating the deformation in narrow bands or shear margins. Crevasses form, particularly around the shear margins.
Satellite imagery from the last 20 years has led to advances in our knowledge of ice sheet stability and has shown that many ice streams are getting thinner and retreating because the ocean and climate are warming. The new research shows that ice behavior can successfully be simulated in places where ice streams meet the sea.
The researchers looked at the landscape of the seafloor in Marguerite Bay, in the Antarctic Peninsula, and saw that during a rapid phase of recession 13,000 years ago, retreat paused many times.
Many ice streams are found in channels with beds that are below sea level and that deepen inland. Current theory suggests that ice loss can increase rapidly in deeper water, but the new findings show that channel width plays a crucial role and that narrow bottlenecks in the landscape beneath the ice can cause retreat to slow down.There are many factors that can speed up or slow down climate caused changes in... more
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The countervailing effects don't cancel each other out. They're both signs of the changes we are bringing to the planet.
NASA
In the seas to our north, sea ice is melting at a perilous pace. This year crushed earlier records for the lowest sea-ice extent ever recorded in the Arctic. Some scientists predict that in four years, Arctic sea ice may collapse entirely during the summer months.
It turns out that the northern pole is not the only one setting records with unusual ice patterns. But to the south, the story is different: record-setting sea-ice extent. That is to say: While the ice to the north is melting away, the ice to the south is growing, extended over 19.44 million square kilometers this year, breaking the previous record (set in 2006) of 19.39 million square kilometers..
Now, lest you get all, "Phew. So glad this who global warming thing is being balanced out," let me tell you plainly: That is not how it works. These are not counteracting phenomena that somehow cancel each other out. Both of these sea-ice trends are the result of changes in our planet's climate, but the effects are different because our hemispheres work in different ways.
To begin to understand this, look north first. The ice there is melting for a pretty straightforward reason: It is getting warmer. As the sea ice melts, the dark oceans absorb more of the suns rays than the bright ice (which reflected them), and the process accelerates.
The south has a more complicated story, with several converging reasons for the ice accretion. The first reason is our depleted ozone layer, which has brought cooler winds and stormier weather. Scientists think that the hole in the ozone has brought temperatures in the stratosphere over Antarctica (about 6 to 37 miles overhead) down by 2 to 6 degrees Celsius. The increased winds push the sea ice around, opening up gaps of water called polynyas where more ice develops rapidly.
Another possible contributing force is an increasingly temperature-stratified ocean. As NASA explained in 2009:
Changes in ocean circulation may also play a role. Jinlun Zhang, an oceanographer at the University of Washington, has pieced together a complex computer model that helps explain why Antarctic sea ice is expanding even with signs that ocean and air temperatures are on the rise. The key is that warming temperatures can lead to more stratified ocean layers.
In the Southern Ocean, there's a layer of cold water near the surface and a layer of warmer water below. Normally, convection causes the two layers to mix and exchange water, a process that brings heat from the lower layers to the surface layer and ultimately helps keep sea ice expansion in check. This transfer of heat is the primary reason that first-year ice in the Antarctic is much thinner than in the Arctic.
But if global air temperatures warm, the model indicates that the amount of rain and snowfall could increase, and surface waters could freshen. Since fresh water is less dense and less apt to mix with the heavier, saltier, and warmer water below, the layer at the ocean's surface could become more stratified and mix less. This, in turn, would reduce the amount of heat flowing upward, allowing surface ice to expand.
One last thing to note: Besides that the polar effects are moving in opposite directions (polar opposites, get it?), the magnitude of the changes are not even close.
The minimum extent of Arctic sea ice is declining by an average of some 91,600 square kilometers per year. Antarctica, in contrast, is gaining ice by about 17,000 square kilometers a year. But even if the pace *were* the same, where would that leave us?
No amount of ice at the South Pole is going to get us out of the jam we're in.The countervailing effects don't cancel each other out. They're both signs... more
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http://news.yahoo.com/experts-global-warming-means-more-antarctic-ice-194009890.html
WASHINGTON (AP) — The ice goes on seemingly forever in a white pancake-flat landscape, stretching farther than ever before. And yet in this confounding region of the world, that spreading ice may be a cockeyed signal of man-made climate change, scientists say.
This is Antarctica, the polar opposite of the Arctic.
While the North Pole has been losing sea ice over the years, the water nearest the South Pole has been gaining it. Antarctic sea ice hit a record 7.51 million square miles in September. That happened just days after reports of the biggest loss of Arctic sea ice on record.
Climate change skeptics have seized on the Antarctic ice to argue that the globe isn't warming and that scientists are ignoring the southern continent because it's not convenient. But scientists say the skeptics are misinterpreting what's happening and why.
Shifts in wind patterns and the giant ozone hole over the Antarctic this time of year — both related to human activity — are probably behind the increase in ice, experts say. This subtle growth in winter sea ice since scientists began measuring it in 1979 was initially surprising, they say, but makes sense the more it is studied.
"A warming world can have complex and sometimes surprising consequences," researcher Ted Maksym said this week from an Australian research vessel surrounded by Antarctic sea ice. He is with the Woods Hole Oceanographic Institution in Massachusetts.
Many experts agree. Ted Scambos of the National Snow and Ice Data Center in Colorado adds: "It sounds counterintuitive, but the Antarctic is part of the warming as well."
And on a third continent, David Vaughan of the British Antarctic Survey says that yes, what's happening in Antarctica bears the fingerprints of man-made climate change.
"Scientifically the change is nowhere near as substantial as what we see in the Arctic," says NASA chief scientist Waleed Abdalati, an ice expert. "But that doesn't mean we shouldn't be paying attention to it and shouldn't be talking about it."
Sea ice is always melting near one pole while growing around the other. But the overall trend year to year is dramatically less ice in the Arctic and slightly more in the Antarctic.
It's most noticeable in September, when northern ice is at its lowest and southern ice at its highest. For over 30 years, the Arctic in September has been losing an average of 5.7 square miles of sea ice for every square mile gained in Antarctica.
Loss of sea ice in the Arctic can affect people in the Northern Hemisphere, causing such things as a higher risk of extreme weather in the U.S. through changes to the jet stream, scientists say. Antarctica's weather peculiarities, on the other hand, don't have much effect on civilization.
At well past midnight in Antarctica, where it's about 3 degrees, Maksym describes in a rare ship-to-shore telephone call from the R.V. Aurora Australis what this extra ice means in terms of climate change. And what it's like to be out studying it for two months, with the nearest city 1,500 miles away.
"It's only you and the penguins," he says. "It's really a strikingly beautiful and stark landscape. Sometimes it's even an eerie kind of landscape."
While the Arctic is open ocean encircled by land, the Antarctic — about 1.5 times the size of the U.S. — is land circled by ocean, leaving more room for sea ice to spread. That geography makes a dramatic difference in the two polar climates.
The Arctic ice responds more directly to warmth. In the Antarctic, the main driver is wind, Maksym and other scientists say. Changes in the strength and motion of winds are now pushing the ice farther north, extending its reach.
Those changes in wind are tied in a complicated way to climate change from greenhouse gases, Maksym and Scambos say. Climate change has created essentially a wall of wind that keeps cool weather bottled up in Antarctica, NASA's Abdalati says.
And the wind works in combination with the ozone hole, the huge gap in Earth's protective ozone layer that usually appears over the South Pole. It's bigger than North America.
It's caused by man-made pollutants chlorine and bromine, which are different from the fossil fuel emissions that cause global warming. The hole makes Antarctica even cooler this time of year because the ozone layer usually absorbs solar radiation, working like a blanket to keep the Earth warm.
And that cooling effect makes the winds near the ground stronger and steadier, pushing the ice outward, Scambos says.
University of Colorado researcher Katherine Leonard, who is on board the ship with Maksym, says in an email that the Antarctic sea ice is also getting snowier because climate change has allowed the air to carry more moisture.
Winter sea ice has grown by about 1 percent a decade in Antarctica. If that sounds small, it's because it's an average. Because the continent is so large, it's a little like lumping together the temperatures of the Maine and California coasts, Vaughan says.
Mark Serreze, director of the snow and ice data center, says computer models have long predicted that Antarctica would not respond as quickly to global warming as other places. Since 1960, the Arctic has warmed the most of the world's regions, and Antarctica has warmed the least, according to NASA data.
Scientists on the cruise with Maksym are spending eight to 12 hours a day on the ice bundled up against the fierce wind with boots that look like Bugs Bunny's feet. It's dangerous work. Cracks in sea ice can form at any time. Just the other day a sudden fissure stranded a team of scientists until an inflatable bridge rescued them.
"It's a treacherous landscape," Vaughan says.http://news.yahoo.com/experts-global-warming-means-more-antarctic-ice-194009890.html... more
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Two new research papers published today improve our understanding of the planet's methane emissions, and might raise worries about the role of the gas in warming the planet. The first suggests that there may be extensive methane deposits under the Antarctic ice sheets. Meanwhile, the second concludes that emissions of the gas from Arctic permafrost have been underestimated.
Methane is a potent greenhouse gas - accounting for around 14 per cent of the warming effect of current man made greenhouse gas emissions. Recent research has focused on measuring emissions from methane sources, both natural and manmade.
Antarctic methane reservoirs
Scientists have been particularly interested in methane emitted from the Arctic. This is because the region is warming particularly rapidly. In addition, methane released from melting permafrost and escaping methane hydrate deposits could exacerbate climate change. But research published today in the journal Nature suggests for the first time that there might also be large stores of methane at the other end of the planet, under the Antarctic ice sheet.
Plants thrived on Antarctica before the continent was covered by ice some 35 million years ago. Lab experiments show that microbes living beneath the ice are able to convert plant remains into methane, and scientists calculate that half of the West Antarctic Ice Sheet (1 million square kilometers) and a quarter of the East Antarctic Ice Sheet (2.5 million square kilometers) could cover carbon-rich sediments containing up to 4 billion metric tons of methane in the form of methane hydrates. These are an ice-like substance formed when methane and water combine.
The researchers suggest methane could be released if ice sheets retreat as global warming continues. According to study co-author Slawek Tulaczyk, professor of Earth and planetary sciences at UC Santa Cruz, the findings underline "the need for continued scientific exploration of remote sub-ice environments in Antarctica, because they may have far greater impact on Earth's climate system than we have appreciated in the past."
Media outlets have reported the findings widely, with most headlines focusing on potential impacts of escaping methane. For example, Reuters headlines the story ' Antarctic methane could worsen global warming - scientists', while the UK Press Agency goes for ' Methane fear beneath Antarctic ice'.
So how realistic is the prospect of enough of the Antarctic melting to release methane that might be beneath the ice?
The study's authors highlight that "significant uncertainty exists" in their estimates of methane reservoirs beneath Antarctic ice. But they calculate that Antarctic ice sheet retreat at the rate of 1,000 square kilometres per year - comparable to previous episodes of ice sheet collapse - could result in enough methane release to affect atmospheric methane levels.
At the moment, this isn't happening. The West Antarctic ice sheet is losing ice mass, but slower than an ice sheet which is collapsing. And with most of the potential methane under the East Antarctic ice sheet, it looks unlikely that there will be significant methane release from Antarctica soon.
Arctic methane underestimated
What about Arctic methane sources? Another new Nature paper finds ten times more carbon than previously thought is escaping from coastal permafrost in the East Siberian Arctic Shelf - an amount that dwarfs emissions from land and submarine permafrost in the region.
The escaping carbon has been trapped for tens of thousands of years, but with summer sea ice declining, Arctic coastlines are becoming more vulnerable to erosion from waves and storms. With roughly three-quarters of the Arctic coastline made of permafrost, it is perhaps not surprising that the crumbling coastline is releasing more methane and carbon dioxide than previously estimated.
The scientists warn that erosion of permafrost coasts might worsen as the Arctic warms, and that this will have "consequences for the temperatures all over the world."
More at the linkTwo new research papers published today improve our understanding of the planet's... more
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Pollen grains and leaf waxes record vegetation on Antarctica during a time of global warmth 20-15 million years ago, when greenhouse gas concentrations may have been similar to projections for the end of the 21st Century. Image credit: Sophie Warny and Kate Griener (Louisiana State University, Baton Rouge)Pollen grains and leaf waxes record vegetation on Antarctica during a time of global... more
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ScienceDaily (June 17, 2012) — A new university-led study with NASA participation finds ancient Antarctica was much warmer and wetter than previously suspected. The climate was suitable to support substantial vegetation -- including stunted trees -- along the edges of the frozen continent.
The team of scientists involved in the study, published online June 17 in Nature Geoscience, was led by Sarah J. Feakins of the University of Southern California in Los Angeles, and included researchers from NASA's Jet Propulsion Laboratory in Pasadena, Calif., and Louisiana State University in Baton Rouge.
By examining plant leaf wax remnants in sediment core samples taken from beneath the Ross Ice Shelf, the research team found summer temperatures along the Antarctic coast 15 to 20 million years ago were 20 degrees Fahrenheit (11 degrees Celsius) warmer than today, with temperatures reaching as high as 45 degrees Fahrenheit (7 degrees Celsius). Precipitation levels also were found to be several times higher than today.
"The ultimate goal of the study was to better understand what the future of climate change may look like," said Feakins, an assistant professor of Earth sciences at the USC Dornsife College of Letters, Arts and Sciences. "Just as history has a lot to teach us about the future, so does past climate. This record shows us how much warmer and wetter it can get around the Antarctic ice sheet as the climate system heats up. This is some of the first evidence of just how much warmer it was."
Scientists began to suspect that high-latitude temperatures during the middle Miocene epoch were warmer than previously believed when co-author Sophie Warny, assistant professor at LSU, discovered large quantities of pollen and algae in sediment cores taken around Antarctica. Fossils of plant life in Antarctica are difficult to come by because the movement of the massive ice sheets covering the landmass grinds and scrapes away the evidence.
"Marine sediment cores are ideal to look for clues of past vegetation, as the fossils deposited are protected from ice sheet advances, but these are technically very difficult to acquire in the Antarctic and require international collaboration," said Warny.
Tipped off by the tiny pollen samples, Feakins opted to look at the remnants of leaf wax taken from sediment cores for clues. Leaf wax acts as a record of climate change by documenting the hydrogen isotope ratios of the water the plant took up while it was alive.
"Ice cores can only go back about one million years," Feakins said. "Sediment cores allow us to go into 'deep time.'"
Based upon a model originally developed to analyze hydrogen isotope ratios in atmospheric water vapor data from NASA's Aura spacecraft, co-author and JPL scientist Jung-Eun Lee created experiments to find out just how much warmer and wetter climate may have been.
"When the planet heats up, the biggest changes are seen toward the poles," Lee said. "The southward movement of rain bands associated with a warmer climate in the high-latitude southern hemisphere made the margins of Antarctica less like a polar desert, and more like present-day Iceland."
The peak of this Antarctic greening occurred during the middle Miocene period, between 16.4 and 15.7 million years ago. This was well after the age of the dinosaurs, which became extinct 64 million years ago. During the Miocene epoch, mostly modern-looking animals roamed Earth, such as three-toed horses, deer, camel and various species of apes. Modern humans did not appear until 200,000 years ago.
Warm conditions during the middle Miocene are thought to be associated with carbon dioxide levels of around 400 to 600 parts per million (ppm). In 2012, carbon dioxide levels have climbed to 393 ppm, the highest they've been in the past several million years. At the current rate of increase, atmospheric carbon dioxide levels are on track to reach middle Miocene levels by the end of this century.
High carbon dioxide levels during the middle Miocene epoch have been documented in other studies through multiple lines of evidence, including the number of microscopic pores on the surface of plant leaves and geochemical evidence from soils and marine organisms. While none of these 'proxies' is as reliable as the bubbles of gas trapped in ice cores, they are the best evidence available this far back in time. While scientists do not yet know precisely why carbon dioxide was at these levels during the middle Miocene, high carbon dioxide, together with the global warmth documented from many parts of the world and now also from the Antarctic region, appear to coincide during this period in Earth's history.
This research was funded by the U.S. National Science Foundation with additional support from NASA. The California Institute of Technology in Pasadena manages JPL for NASA.ScienceDaily (June 17, 2012) — A new university-led study with NASA... more
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The world's ice sheets serve as cold-storage for creatures the Earth hasn't seen in eons. Scientists don't expect another Contagion or Andromeda Strain, but the release of unknown life forms does pose new concerns about effects of global warming.
By Cheryl Katz
The Daily Climate
BOZEMAN, Mont. – Locked in frozen vaults on Antarctica and Greenland, a lost world of ancient creatures awaits another chance at life. Like a time-capsule from the distant past, the polar ice sheets offer a glimpse of tiny organisms that may have been trapped there longer than modern humans have walked the planet, biding their time until conditions change and set them free again.
It's a way of recycling genomes. You put something on the surface of the ice and a million years later it comes back out.
- John Priscu, Montana State University
With that ice melting at an alarming rate, those conditions could soon be at hand. Masses of bacteria and other microbes – some of which the world hasn't seen since the Middle Pleistocene, a previous period of major climate change about 750,000 years ago – will make their way back into the environment.
Once thought to be too harsh and inhospitable to support any living thing, the ice sheets are now known to be a gigantic reservoir of microbial life. Altogether, the biomass of microbial cells in and beneath the ice sheet may amount to more than 1,000 times that of all the humans on Earth.
Internment in the ice amounts to an evolutionary strategy for microorganisms: preserving genetic blueprints by storing them in deep–freeze for a future re-entry, said John Priscu, a Montana State University professor and pioneer in the study of Antarctic microbiology.
"It's a way of recycling genomes," he said. "You put something on the surface of the ice and a million years later it comes back out."
'Storehouse for genes'
Priscu has spent the past 28 Austral summers on the southernmost continent, studying what he calls "the bugs in the ice sheet." Antarctica has the oldest ice on Earth; parts of its glacial landscape date back about a million years, and some pockets are believed to be up to 8 million years old. "There's a lot of history in that ice sheet," said Priscu.
Much of that history appears to still be alive. Priscu has found living bacteria in cores of 420,000-year-old ice and gotten them to grow in his laboratory. Other researchers report bringing far older bacteria back to life.
We don't really understand how an organism can sit around for 750,000 years in some sort of suspended animation like when Han Solo was put in carbonite.
- Brent Christner,
Louisiana State University
The ice allows microbes to enjoy a sort of immortality, preserving ancient genetic material and allowing creatures that have long disappeared from the planet to someday return. "That's what's interesting about the ice – it can serve as a storehouse for those genes," said Jonathan Klassen, an evolutionary biologist and postdoctoral research fellow at the University of Wisconsin, Madison. "Things that went extinct have the possibility of coming back."
Could this be Jurassic Park on Ice? Not likely, scientists say. The only things able to survive in these cold, dark, crushed quarters with little to eat or drink are microscopic organisms, and most of what has been found appears related to microbes from other cold and icy environments.
Still, with heat-trapping greenhouse gases warming the polar regions much faster than the rest of the planet today, investigators have many questions about the bugs in the ice sheet.
Researchers are trying to determine how these organisms can survive such a brutal habitat, some seeming to sit in what resembles a state of suspended animation for millennia. The findings could point the way for the discovery of life in other extreme climates, such as frozen planets and moons.
Methane emissions
The more immediate concerns sit here on Earth. Cells and carbon dumped out of melting glaciers could turn into huge piles of decomposing organic matter – compost – that generate carbon dioxide and methane as they decay, a potentially significant source of greenhouse gas emissions that climate researchers have yet to consider.
In addition to the effects on the atmosphere, masses of microorganisms flushed into the sea will certainly challenge marine systems and could upset the oceans' delicate chemistry. [See sidebar: Loss of 'world's largest wetland' could tip ocean balance]
And scientists see evidence that the microbes are evolving inside the ice sheets, exchanging DNA and gaining new traits. While these cold-loving organisms appear to pose little threat to warm-blooded creatures, they could force out existing microbial populations, with unknown consequences. [See sidebar: Warming climate sets evolution within ice to high]
The frozen "bacteriasicles," as Louisiana State University microbiologist Brent Christner describes them, can emerge from the ice after hundreds of thousands of years poised to grow and divide when favorable conditions arise. Christner, an associate professor in the Department of Biological Sciences, has revived bacteria encased in 750,000-year-old ice.
More at the linkThe world's ice sheets serve as cold-storage for creatures the Earth hasn't... more
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A Yale-led study of the evolutionary history of Antarctic fish and their "anti-freeze" proteins illustrates how tens of millions of years ago a lineage of fish adapted to newly formed polar conditions - and how today they are endangered by a rapid rise in ocean temperatures.
"A rise of 2 degrees centigrade of water temperature will likely have a devastating impact on this Antarctic fish lineage, which is so well adapted to water at freezing temperatures," said Thomas Near, associate professor of ecology and evolutionary biology and lead author of the study published online the week of Feb. 13 in the Proceedings of the National Academy of Sciences.
The successful origin and diversification into 100 species of fish, collectively called notothenioids, is a textbook case of how evolution operates. A period of rapid cooling led to mass extinction of fish acclimated to a warmer Southern Ocean.
The acquisition of so-called antifreeze glycoproteins enabled notothenioids to survive in seas with frigid temperatures. As they adapted to vacant ecological niches, new species of notothenioids arose and contributed to the rich biodiversity of marine life found today in the waters of Antarctica.
Notothenioids account for the bulk of the fish diversity and are a major food source for larger predators, including penguins, toothed whales, and seals. Yale's Peabody Museum of Natural History has one of the most important collections of these specimens in the world.
However, the new study suggests the acquisition of the antifreeze glycoproteins 22 to 42 million years ago was not the only reason for the successful adaptation of the Antarctic notothenioids. The largest radiation of notothenioid fish species into new habitats occurred at least 10 million years after the first appearance of glycoproteins, the study found.
"The evolution of antifreeze was often thought of as a 'smoking gun,' triggering the diversification of these fishes, but we found evidence that this adaptive radiation is not linked to a single trait, but to a combination of factors," Near said.
This evolutionary success story is threatened by climate change that has made the Southern Ocean around Antarctica one of the fastest-warming regions on Earth. The same traits that enabled the fish to survive and thrive on a cooling earth make them particularly susceptible to a warming one, notes Near.
"Given their strong polar adaptations and their inability to acclimate to warmer water temperatures, climate change could devastate this most interesting lineage of fish with a unique evolutionary history," Near said.A Yale-led study of the evolutionary history of Antarctic fish and their... more
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It took researches 30 years of drilling through a four-kilometer-thick ice to reach the renowned subglacial lake. Most importantly, million years-old secrets will be unveiled without causing harm to the lake's ecosystem. "2/5/2012 our scientists at the Vostok polar station in the Antarctic completed drilling at depths of 3,768 meters and reached surface of the subglacial lake," RIA Novosti quoted unnamed Russian scientist. Lake Vostok is a unique aquatic ecosystem hidden under some four kilometers of ice. Its water has been isolated from the atmosphere -- and therefore from the outer biosphere -- for millions of years. Scientists believe that surveys of the lake can provide invaluable details on past and future climate changes. http://www.makeahistory.com/index.php/your-details/43060-20-million-years-old-antarctic-secret-scientists-find-ancient-vostok-lake-under-4-kilometers-of-iceIt took researches 30 years of drilling through a four-kilometer-thick ice to reach... more
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13,000 feet beneath the surface of Antarctica's vast ice sheet rests the otherworldly Lake Vostok. Home to some of the most extreme conditions on Earth, Vostok has remained isolated from the rest of the world for 20 million years, and completely inaccessible to mankind. Until now.
Yesterday, reports originating from Ria Novosti — a state-run, Russian news agency — began to circulate, indicating that the twenty-year mission to reach Vostok's ice-entombed waters had finally reached its goal. Other media outlets were quick to pick up the news as well, citing an unnamed scientific source, who claimed that, "Yesterday [February, 5], our scientists stopped drilling at the depth of 3,768 meters and reached the surface of the sub-glacial lake."
Whether the team has finally drilled through to the Lake, however, remains to be seen. Is it likely? Yes. A spokesperson from the Russian Antarctic Expedition in St. Petersburg told New Scientist this morning that the drill did make contact with water last week, and that the water was automatically drawn up into the borehole, as planned.
But the team must now check the water levels in the borehole, and readings from their equipment's pressure sensors, to confirm that the water is, in fact, from Vostok — and not from a pocket of water in the layers of ice overlaying the lake. The fact that this confirmation process is ongoing probably explains why there is still no official announcement on the website of Russia's Arctic and Antarctic Research Institute (the government agency that heads up the country's polar science expeditions). Valery Lukin, director of the Russian Antarctic Program, told Nature this morning that the team's data could be processed by as early as tomorrow.
In any case, even if the lake has been breached, it will still be almost a year before Russia's scientists have an opportunity to address the question that everyone is so anxious to know the answer to: whether Vostok's pitch-black waters — which have been cut off from light for millions of years — harbor any weird new life forms. If they do, it would strengthen the prospect of discovering exoplanetary life in the subsurface waters of Jupiter's moon Europa, Saturn's moon Enceladus, and any other cosmic bodies that harbor water, subglacial or otherwise.
And if they don't? Well, that would be disappointing (after all, who wouldn't want to discover a new species of subglacial extremophile?), but it would also be incredibly interesting. After all, everywhere on this planet that we've found water, we've found life; to not find it in the waters of Vostok — the third largest lake by volume on Earth — would be totally unprecedented.
http://io9.com/5882868/scientists-have-probably-made-contact-with-earths-most-alien-lake13,000 feet beneath the surface of Antarctica's vast ice sheet rests the... more
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It has been five days since anyone has communicated with Russian scientists, who are in a remote Antarctic 'station,' where they are drilling through 13,000 feet of an ice sheet to reach the prehistoric Lake Vostok. Now the scientific community is anxiously waiting to hear what's become of them.
"Temps are dropping below -40 Celsius and they have only a week or so left before they have to winterize the station," said John Priscu, an Antarctic research expert at Montana State University, in an interview with Fox News. "I can only imagine what things must be like at Vostok Station this week."
The scientists are presumed to be on the surface of the ice sheet near the Vostok Station, where they were expected to conclude two decades of efforts to drill through to what has been deemed the most "alien lake on Earth," sealed off from the planet's atmosphere for 20 million years. Geothermal vents are theorized to sustain life beneath the lake, from primordial microbes to monstrous tube worms.
To prevent contamination of the lake, they have attempted to drill only deep enough to let frozen slush on its surface flow up through the borehole, but it is possible that pressurized gas could escape explosively, raising concerns about the scientists' safety.
"If it goes well, a breakthrough opens up a whole new chapter in our understanding of our planet and possibly moons in our solar system and planets far beyond," Priscu told the Washington Post. "If it doesn't go well, it casts a pall over the whole effort to explore this wet underside of Antarctica."
http://www.ibtimes.com/articles/292793/20120203/lake-vostok-antarctica-russia-scientists-alien-geothermal.htmIt has been five days since anyone has communicated with Russian scientists, who are... more
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This is becoming an intriguing story, many other scientists from other country's have been warning not to finish drilling in fear of what might be released from the frozen lake for millions of years! I wonder if a drone attack got em?
A group of Russian scientists plumbing the frozen Antarctic in search of a lake buried in ice for tens of millions of years have failed to respond to increasingly anxious U.S. colleagues -- and as the days creep by, the fate of the team remains unknown.
"No word from the ice for 5 days," Dr. John Priscu professor of Ecology at Montana State University, told FoxNews.com via email.
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The team from Russia's Arctic and Antarctic Research Institute (AARI) have been drilling for weeks in an effort to reach isolated Lake Vostok, a vast, dark body of water hidden 13,000 ft. below the ice sheet's surface. The lake hasn't been exposed to air in more than 20 million years.
Priscu said there was no way to get in touch with the team -- and the already cold weather is set to plunge, as Antarctica's summer season ends and winter sets in.
"Temps are dropping below -40 Celsius [-40 degrees Fahrenheit] and they have only a week or so left before they have to winterize the station," he said. "I can only imagine what things must be like at Vostok Station this week."
The team's disappearance could not come at a worse time: They are about 40 feet from their goal of reaching the body of water, Priscu explained, a goal that the team was unable to meet as they raced the coming winter exactly one year ago.
When the winter arrives in the next few weeks, the temperature can get twice as freezing. Vostok Station boasts the lowest recorded temperature on Earth: -89.4 degrees Celsius (-129 degrees Fahrenheit).
If the team does reach the lake water, they will bring its water up through the hole and let it freeze there over the winter. The following year they will be able to start research on what they find, Priscu explained.
While there are only a few researchers actually working at the lake, scientists around the globe have been waiting with baited breath to see what the Russian's unearth this weekend.
"We are terribly interested in what they find," Alan Rodger, a scientist at the British Antarctic Survey, told FoxNews.com last year. "This is a lake that we don't think has been exposed for 15 million years. Therefore, if there is life there, we're going to have so many questions. How has it evolved over those years, how has it survived, what does it look like? Won't it be exciting to find something completely new on Planet Earth?"
Hey, where's the lake? Hidden beneath nearly 2 miles of ice in Western Antarctica.
The Lake Vostok project has been years in the making, with initial drilling at the massive lake -- 15,690 square kilometers (6,060 sq mi) -- starting in 1998. Initially, they were able to reach 3,600 meters, but had to stop due to concerns of possible contamination of the never-before-touched lake water.
"Ice isn't like rock, it's capable of movement," Dr. Priscu told FoxNews.com. "So in order to keep the hole from squeezing shut, they put a fluid in the drill called kerosene. Kerosene also grows bacteria, and there's about 65 tons of kerosene in that hole. It would be a disaster if that kerosene contaminated this pristine lake."
But the scientists came up with a clever way to make sure this debacle would not occur. They agreed to drill until a sensor warned them of free water. At that point they will take out the right amount of kerosene and adjust the pressure so that none of the liquids fall into the lake, but rather lake water would rise through the hole.
Priscu was concerned for his colleagues, but also admits the stunning scope of the story.
"It could be fodder for a great made-for-TV movie," he said.This is becoming an intriguing story, many other scientists from other country's... more
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