Another climate-change nightmare: 91 new volcanoes beneath Antarctica’s ice, WP , By Avi SelkAugust 15 “….now it turns out Antarctica has problems we didn’t even know about. Deep problems. Volcanoes-under-the-ice problems, which doesn’t sound healthy.
University of Edinburgh researchers on Monday announced the discovery of 91 previously unknown volcanoes under west Antarctica. They do not sound nearly as alarmed as, say, Quartz, which called the possibilities terrifying.
“By themselves the volcanoes wouldn’t be likely to cause the entire ice sheet to melt,” said lead researcher Max Van Wyk de Vries, whose team published the study in the Geological Society in late May. But if the glacier is already melting because of global warming, he said, “if we start reducing significant quantities of ice … you can more or less say that it triggers an eruption.”
In a worst-case scenario, the researchers say, we could see a feedback loop of melting ice that destabilizes volcanoes, which erupt and melt more ice, and so on until Antarctica’s troubles to date seem halcyon in comparison……
While some are quite worried, de Vries doubted that a little blast of molten rock would do much harm to a massive Antarctic ice sheet. Directly, at least.
Study validates East Antarctic ice sheet to remain stable even if western ice sheet melts https://www.eurekalert.org/pub_releases/2017-08/iu-sve081717.php INDIANA UNIVERSITY, INDIANAPOLIS — A new study from Indiana University-Purdue University Indianapolis validates that the central core of the East Antarctic ice sheet should remain stable even if the West Antarctic ice sheet melts.
The study’s findings are significant, given that some predict the West Antarctic ice sheet could melt quickly due to global warming.
If the East Antarctic ice sheet, which is 10 times larger than the western ice sheet, melted completely, it would cause sea levels worldwide to rise almost 200 feet, according to Kathy Licht, an associate professor in the Department of Earth Sciences in the School of Science at IUPUI.
Licht led a research team into the Transarctic Mountains in search of physical evidence that would verify whether a long-standing idea was still true: The East Antarctic ice sheet is stable.
The East Antarctic ice sheet has long been considered relatively stable because most of the ice sheet was thought to rest on bedrock above sea level, making it less susceptible to changes in climate. However, recent studies show widespread water beneath it and higher melt potential from impinging ocean water.
The West Antarctic ice sheet is a marine-based ice sheet that is mostly grounded below sea level, which makes it much more susceptible to changes in sea level and variations in ocean temperature.
“Some people have recently found that the East Antarctic ice sheet isn’t as stable as once thought, particularly near some parts of the coast,” Licht said. Recent studies have determined that the perimeter of the East Antarctic ice sheet is potentially more sensitive and that the ice may have retreated and advanced much more dynamically than was thought, Licht said.
“We believed this was a good time to look to the interior of the ice sheet. We didn’t really know what had happened there,” Licht said.
The research team found the evidence confirming the stability of the East Antarctic ice sheet at an altitude of 6,200 feet, about 400 miles from the South Pole at the edge of what’s called the polar plateau, a flat, high surface of the ice sheet covering much of East Antarctica.
To understand how an ice sheet changes through time, a continuous historical record of those changes is needed, according to Licht. The team found layers of sediment and rocks that built up over time, recording the flow of the ice sheet and reflecting climate change. Finding that record was a challenge because glaciers moving on land tend to wipe out and cover up previous movements of the glacier, Licht said.
The big question the team wanted to answer was how sensitive the East Antarctic sheet might be to climate change.
“There are models that predict that the interior of the East Antarctic ice sheet wouldn’t change very much, even if the West Antarctic ice sheet was taken away,” Licht said. According to these models, even if the ice sheet’s perimeter retreats, its core remains stable.
“It turns out that our data supports those models,” she said. “It’s nice to have that validation.”
The team’s research findings are presented in a paper, “East Antarctic ice sheet stability recorded in a high-elevation ice-cored moraine,” that was published today online in the journal Geology. The research presented is in collaboration with Mike Kaplan, Gisela Winckler, Joerg Schaefer and Roseanne Schwartz at Lamont-Doherty Earth Observatory in New York.
Not all glaciers in Antarctica have been affected by climate change https://www.eurekalert.org/pub_releases/2017-08/gsoa-nag080817.phpGEOLOGICAL SOCIETY OF AMERICA Boulder, Colo., USA: A new study by scientists at Portland State University and the National Snow and Ice Data Center (NSIDC) at the University of Colorado Boulder has found that the effects of climate change, which are apparent in other parts of the Antarctic continent, are not yet observed for glaciers in the western Ross Sea coast.
Published online ahead of print for the journal Geology, the study found that the pattern of glacier advance and retreat has not changed along the western Ross Sea coast, in contrast to the rapidly shrinking glaciers on the Antarctic Peninsula.
The western Ross Sea is a key region of Antarctica, home to a complex and diverse ocean ecosystem, and the location of several Antarctic research stations including the U.S. McMurdo Station, the largest on the continent.
The research team compiled historic maps and a variety of satellite images (such as https://eoimages.gsfc.nasa.gov/images/imagerecords/2000/2066/seawifs_south_pole_ross_lrg.jpg) spanning the last half-century to examine glacier activity along more than 700 kilometers of coastline. The NASA-U.S. Geological Survey (USGS) Landsat series satellites were particularly useful, including the newest Landsat 8 instrument, launched in 2013.
The scientists examined 34 large glaciers for details of ice flow, extent, and calving events (formation of icebergs). Although each glacier showed advances and retreats, there was no overall pattern over time or with latitude.
The results suggest that changes in the drivers of glacier response to climate — air temperature, snowfall, and ocean temperatures — have been minimal over the past half century in this region.
The study was part of a National Science Foundation and U.S. Geological Survey study and was motivated by previous work documenting significant glacier retreat and ice shelf collapse along the coastline of the Antarctic Peninsula. The region’s ongoing changes were highlighted recently with the cracking and separation of a large iceberg from the Larsen C Ice Shelf.
Earlier studies had documented little change in the western Ross coastline prior to 1995, and the new study both confirmed the earlier work and extended the analysis to the present time.
This work underscores the complexity of Antarctic climate change and glacier response.
A massive crack in one of Antarctica’s largest ice shelves creates an iceberg bigger than Kangaroo Island. So, what impact will it have?
The 1-trillion-tonne iceberg, measuring 5,800 square kilometres, calved away from the Larsen C ice shelf in Antarctica sometime between July 10 and 12, scientists at the University of Swansea and the British Antarctic Survey said.
The iceberg has been close to breaking off for a few months. Throughout the Antarctic winter, scientists monitored the progress of the rift in the ice shelf using the European Space Agency satellites.
“The iceberg is one of the largest recorded and its future progress is difficult to predict,” said Adrian Luckman, professor at Swansea University and lead investigator of Project MIDAS, which has been monitoring the ice shelf for years.
“It may remain in one piece but is more likely to break into fragments. Some of the ice may remain in the area for decades, while parts of the iceberg may drift north into warmer waters,” he added.
The ice will add to risks for ships now it has broken off.
The peninsula is outside major trade routes but is the main destination for cruise ships visiting from South America.
In 2009, more than 150 passengers and crew were evacuated after the MTV Explorer sank after striking an iceberg off the Antarctic peninsula.
The iceberg, which is likely to be named A68, was already floating before it broke away so there is no immediate impact on sea levels, but the calving has left the Larsen C ice shelf reduced in area by more than 12 per cent.
The Larsen A and B ice shelves, which were situated further north on the Antarctic Peninsula, collapsed in 1995 and 2002, respectively.
“This resulted in the dramatic acceleration of the glaciers behind them, with larger volumes of ice entering the ocean and contributing to sea-level rise,” said David Vaughan, glaciologist and director of science at British Antarctic Survey.
“If Larsen C now starts to retreat significantly and eventually collapses, then we will see another contribution to sea level rise,” he added. Big icebergs break off Antarctica naturally, meaning scientists are not linking the rift to manmade climate change.
The ice, however, is a part of the Antarctic peninsula that has warmed quickly in recent decades.
“In the ensuing months and years, the ice shelf could either gradually regrow, or may suffer further calving events which may eventually lead to collapse — opinions in the scientific community are divided,” Professor Luckman said.
“Our models say it will be less stable, but any future collapse remains years or decades away.”
A huge part of Antarctica is melting and scientists say that’s bad news, CNN, By AJ Willingham, June 20, 2017NASA: Rising sea levels more dangerous than thought
Story highlights
Rain and significant ice melts in Antarctica surprised scientists
In the future, these events could cause ice to melt and break off, which would make sea levels rise
(CNN)Antarctica is experiencing weird weather, and the changes have some scientists worried about the future.
There’s an area on the west side of the icy continent called the West Antarctic Ice Sheet, and last January, scientists found a 300,000-square-mile portion of its perimeter was melting. That’s an area roughly two times the size of California, covered in slush.
“A melt of this magnitude is relatively rare in Antarctica,” said Julien Nicolas, one of the paper’s authors at the Ohio State University Byrd Polar and Climate Research Center. “There have been about three or four events of this size in the last 40 years.”
For more than two weeks in January 2016, a passive microwave satellite observed surface ice melt two times the size of California.
The news also is ominous for another reason: It means the West Antarctic Ice Sheet is essentially being melted from both sides. El Niños push warm water under the sheet. On top, colder westerly winds usually do enough to stave off any approaching warm weather, but in the 2016 incident, they didn’t.
This event also brought about another surprise for scientists: Rain.
“We saw in our observations that there were some rain, we heard from some parties on the Ross Ice Shelf, and we saw it on the weather models,” Nicolas said. “That’s very unusual. We don’t have a record of rain in Antarctica, so we don’t know how often it’s happened in the past.”
Why it matters
Rain and slush would make for a miserable day anywhere, but the weird weather patterns observed over the two-week period in 2016 painted a potentially worrisome picture for the future.
If more extreme El Niños occur, ice shelves such as the Ross Ice Shelf on the West Antarctic Ice Sheet will melt and be weakened. Sometimes, those ice melts can lead to dramatic rivers and waterfalls that leak off of the ice structure. Take a look at a recent video [top of this post] of the Nansen Ice Shelf, which is north of the West Antarctic Ice Sheet:….http://edition.cnn.com/2017/06/19/weather/antarctica-melt-texas-rain-climate-change-trnd/index.html
The main stumbling block that leads policy makers to twist their logic into pretzels is economic growth. Remove the requirement for growth, and it’s barely possible (not easy, but possible) to reconcile carbon reserves, emissions, energy sources, and warming targets—if governments somehow dedicate enough money and policy effort to the job.
If we’re smart, we will recognize that deeper trend and adapt to it in ways that preserve the best of what we have accomplished, and make life as fulfilling as it can be for as many people as possible, even while the amount of energy available to us ratchets downward. We’ll act to rein in population growth and aim for a gradual overall population decline, so that per capita energy use does not have to decline as fast as total use. We’ll act to minimize ecological disruption by protecting habitat and species. We’ll make happiness, not consumption, the centerpiece of economic policy.
If we’re not so smart, we’ll join the dinosaurs.
Coal Is a Dinosaur and so is the growth economy, Post Carbon Institute, Richard Heinberg, June 15, 2017 “……Every few years, the IPCC issues a major new “assessment” crammed with data and models, aimed at informing policy makers. Unfortunately, these assessments are also filled with what Oliver Gedens has called “magical thinking……
The only realistic solution to our climate crisis is not to put so much carbon in the atmosphere in the first place. But that path runs counter to expectations about economic growth—which requires energy. And that is almost surely at the root of the IPCC’s assumptions about future fossil fuel consumption (regardless of whether those fossil fuels are actually available to be consumed).
So far humanity has increased the global atmospheric CO2 concentration from 280 parts per million to over 400 ppm—an already dangerous level. David Hughes figures burning our remaining realistic reserves of coal, oil, and natural gas would send us to about 550 ppm. There’s an easy way of not getting to 550 ppm: leave most of those fossil fuel reserves in the ground. But that would sink the economy, unless we very rapidly develop alternative energy sources (nuclear, which is expensive and risky; or solar and wind, which are more realistic alternatives).
Is it even possible to make the energy switch so quickly and completely as to avoid major bumps along the road? Building alternative energy infrastructure will itself require energy, and during the crucial early stages of the transition most of that energy will have to come from fossil fuels. There’s no way to bootstrap the energy transition process with energy from, say solar panels and wind turbines, because wind, and especially solar, technologies take years to energetically pay for their own manufacture and installation. So to avert burning even more fossil fuels than we otherwise would (in order to build all those solar panels, wind turbines, electric cars, heat pumps, and so on), resulting in a big pulse of carbon emissions, we would have to severely curtail the use of fossil fuels for current purposes—the maintenance of business as usual. That would also imperil economic growth. And we are talking about a remarkably small time window available for the shift, compared with the decades required for past energy transitions. It’s all so complicated that one can get a headache just thinking about it.
The main stumbling block that leads policy makers to twist their logic into pretzels is economic growth. Remove the requirement for growth, and it’s barely possible (not easy, but possible) to reconcile carbon reserves, emissions, energy sources, and warming targets—if governments somehow dedicate enough money and policy effort to the job. However, with further economic growth as an absolute requirement, the resulting climate models fester with internal contradictions and with assumptions about speculative technologies that very few people believe can be scaled up sufficiently, and that may have economic, environmental, and political repercussions that no one is prepared to deal with.
We cannot afford to hide the implications of realistic fossil fuels reserves estimates behind magical thinking. Perhaps the most important of those implications is that the world is probably just about at peak energy right now, give or take a decade. If we act immediately and strongly to rein in climate change, then a peak in world energy usage will likely occur more or less immediately. If we don’t act, then we may have another decade before fossil fuel depletion results in peak energy anyway…Renewables will contribute a larger share, depending on investment levels and policy supports, but cannot realistically expand far enough, fast enough, to maintain energy growth and therefore economic growth….
So overall, one way or the other, we have just about hit the maximum burn rate our civilization is likely to achieve, and it’s mostly downhill from here. That has implications for robust economic growth (it’s essentially over), and hence for war and peace, inequality, political stability, and further population expansion. Dealing with the end of energy growth, and therefore economic growth, is the biggest political and social challenge of our time—though it’s unlikely to be recognized as such. (Our biggest ecological challenges consist of climate change, species extinctions, and ocean acidification.) The impacts of the end of growth will likely be masked by financial crashes and socio-political stresses that will rivet everyone’s attention while a quiet trend churns away in the background, undoing all our assumptions and expectations about the world we humans have constructed over the past couple of centuries.
If we’re smart, we will recognize that deeper trend and adapt to it in ways that preserve the best of what we have accomplished, and make life as fulfilling as it can be for as many people as possible, even while the amount of energy available to us ratchets downward. We’ll act to rein in population growth and aim for a gradual overall population decline, so that per capita energy use does not have to decline as fast as total use. We’ll act to minimize ecological disruption by protecting habitat and species. We’ll make happiness, not consumption, the centerpiece of economic policy.
The Larsen C ice shelf collapse hammers home the reality of climate change , Guardian, John Abraham, 12 June 17, Very soon, a large portion of an ice shelf in Antarctica will break off and collapse into the ocean. The name of the ice shelf is Larsen C; it is a major extension from of the West Antarctic ice sheet, and its health has implications for other ice in the region, and sea levels globally.
How do we know a portion is going to collapse? Well, scientists have been watching a major rift (crack) that has grown in the past few years, carving out a section of floating ice nearly the size of Delaware. The speed of the crack has increased dramatically in the past few months, and it is nearly cracked through.
Project Midas provides frequent updates on the Larsen C shelf. You can read a summary there, which reports:
In the largest jump since January, the rift in the Larsen C Ice Shelf has grown an additional 17 km (11 miles) between May 25 and May 31 2017. This has moved the rift tip to within 13 km (8 miles) of breaking all the way through to the ice front, producing one of the largest ever recorded icebergs. The rift tip appears also to have turned significantly towards the ice front, indicating that the time of calving is probably very close.
The rift has now fully breached the zone of soft ‘suture’ ice originating at the Cole Peninsula and there appears to be very little to prevent the iceberg from breaking away completely.
When it calves, the Larsen C Ice Shelf will lose more than 10% of its area to leave the ice front at its most retreated position ever recorded; this event will fundamentally change the landscape of the Antarctic Peninsula. We have previously shown that the new configuration will be less stable than it was prior to the rift, and that Larsen C may eventually follow the example of its neighbor Larsen B, which disintegrated in 2002 following a similar rift-induced calving event……..
Why does all this matter? Well it is important for a number of reasons. First, when an ice shelf melts or collapses, it can unpin other ice that is sitting on land, which allows it to flow more quickly into the ocean. It is this secondary effect – the loss of ice resting on land – that changes the rate of sea level rise. Loss of a major ice shelf can also activate ice that rests on bedrock topography that makes it fundamentally unstable – ice that, once moving, will move faster and faster, until a large region is afloat.
The entire Larsen Ice shelf, which is the fourth largest in Antarctica, covers nearly 50,000 square km (20,000 square miles) according to reporting at ABC science. The ice on the land upstream of the shelf is enough to raise sea level, eventually, by ten centimeters. This is not, by itself, a major threat to the world’s coastlines, but it reveals the path that other, even larger areas are likely to take in the future.
Perhaps a quotation from a seminal work on Antarctic ice sheets best sums up the situation. In a 1978 paper, John Mercer from the Institute of Polar studies concluded:
One of the warning signs that a dangerous warming trend is under way in Antarctica will be the breakup of ice shelves on both coasts of the Antarctic Peninsula, starting with the northernmost and extending gradually southward. These ice shelves should be regularly monitored by LANDSAT imagery.
Larsen C: What will happen when the huge Antarctic ice shelf cracks?, ABC Science By Genelle Weule, 2 June 17, A massive crack in one of Antarctica’s largest ice shelves is very close to breaking point, and when it fractures it will create an iceberg bigger than Kangaroo Island.
The Larsen C ice shelf is located on the Antarctic Peninsula, which juts out towards South America.
A large fracture, which has been growing across the ice sheet for decades, has recently started to accelerate, said Sue Cook, a glaciologist from the Antarctic Climate and Ecosystems Cooperative Research Centre.
According to the latest data by a team of UK scientists, the fracture ripped open by 17 kilometres in the last week of May and turned towards the ocean.
Dr Cook said the lengthening fracture was within 13 kilometres of the sea, and there was nothing to stop it fracturing.
When it breaks it will create an iceberg of 5,000 square kilometres.
Climate stabilization: Planting trees cannot replace cutting CO2 emissions Growing plants and then storing the CO2 they have taken up from the atmosphere is no viable option to counteract unmitigated emissions from fossil fuel burning, a new study shows. http://www.enn.com/pollution/article/51292
At both poles, “a wave of new record lows were set for both daily and monthly extent,” according to the analysis.
In recent years, Arctic sea ice has been hit particularly hard.
“It has been so crazy up there, not just this autumn and winter, but it’s a repeat of last autumn and winter too,” says Mark Serreze, director of the NSIDC.
In years past, abnormal warmth and record low sea ice extent tended to occur most frequently during the warmer months of the year. But for the past two years, things have gotten really weird in the colder months.
In 2015, Serreze says, “you had this amazing heat wave, and you got to the melting point at the North Pole on New Years Eve. And we’ve had a repeat this autumn and winter — an absurd heat wave, and sea ice at record lows.”
Lately, the Southern Hemisphere has been getting into the act. “Now, Antarctic sea ice is very, very low,” Serreze says.
From the NSIDC analysis:
Record low monthly extents were set in the Arctic in January, February, April, May, June, October, and November; and in the Antarctic in November and December.
Put the Arctic and the Antarctic together, and you get his time series of daily global sea ice extent, meaning the Arctic plus Antarctic:
As the graph [on original] shows, the global extent of sea ice tracked well below the long-term average for all of 2016. The greatest deviation from average occurred in mid-November, when sea ice globally was 1.50 million square miles below average.
For comparison, that’s an area about 40 percent as large as the entire United States.
The low extent of sea ice globally “is a result of largely separate processes in the two hemispheres,” according to the NSIDC analysis.
For the Arctic, how much might humankind’s emissions of greenhouse gases be contributing to the long-term decline of sea ice? The graph above [on original] , based on data from a study published in the journal Science, “links Arctic sea ice loss to cumulative CO2emissions in the atmosphere through a simple linear relationship,” according to an analysis released by the NSIDC last December. Based on observations from the satellite and pre-satellite era since 1953, as well as climate models, the study found a linear relationship of 3 square meters of sea ice lost per metric ton of CO2 added to the atmosphere.
That’s over the long run. But over a shorter period of time, what can be said? Specifically, how much of the extreme warmth and retraction of sea ice that has been observed in autumn and winter of both 2015 and 2016 can be attributed to humankind’s emissions of greenhouse gases?
“We’re working on it,” Serreze says. “Maybe these are just extreme random events. But I have been looking at the Arctic since 1982, and I have never seen anything like this.”
We’ve seen a lot of commentary on the fact that utility-scale solar power has become the least expensive source of electricity in many places. There is more than that to be found in the data inLazard’s Levelized Cost of Energy Analysis, Version 10.0, however, and what it tells us is that solar and wind power have benefits apart from the simple facts that their costs are low.
We have always needed a variety of power sources. Conventional baseload power provided by coal-burning and nuclear plants lacks flexibility and is, in fact, a really bad match for grid demand. Baseload generation cannot be ramped up or down as demand changes, and this is one reason why such power plants never provided all of our electricity. There always had to be other, more flexible generating facilities available.
The greatest need for power is often on warm, sunny afternoons, when air conditioners are running in work spaces, stores, and homes, in addition to normal human activities. These have been the times when peaking plants could make their money. With high demand, come the high prices they need to be profitable.
As solar photovoltaics (PV) have come on the market in quantity, however, sunny afternoons suddenly bring the sun as a competing power source. The early evening, after the sun has gone down, is still potentially a time of high demand, when solar power does not cut into the use of fossil-fuel peaking plants. This situation, however, is clearly coming to an end.
According to Lazard, the levelized cost of utility-scale solar power with storage is $92 per megawatt-hour (MWh). This means that solar-plus-storage can be highly competitive, even after dark, with natural gas peaking plants, which have levelized costs ranging from $165 to $217 per MWh. It is even competitive to a degree with gas-powered reciprocating engines, whose costs are from $68 to $101 per MWh.
There is more to this story, however. It happens that wind power is usually strongest when the sun is not shining brightly, and solar power output is often highest when the wind does not blow much. A storage system that is charged by the sun could be charged by the wind when the sun does not shine. This means that a solar-plus-storage system can be made more valuable by storing excess power from wind as needed.
The fact that power from solar-plus-storage is becoming relatively inexpensive makes it likely that the combination will increasingly be used instead of peaking plants using fossil fuels. This will increase production of batteries, and it will increase research and development into storage technologies. And these changes imply further reductions in costs.
The declines in costs of energy storage have already been impressive. Tesla lithium-ion batteries are delivering about double the amount of electricity that they had been providing when they were first introduced, and their cost has not increased appreciably. This implies that the cost of the electricity from them has been roughly halved. Other battery technologies have alsoseenexciting developments. For example the ViZn flow battery shows a number of improvements over earlier designs at considerably lower costs. Salt water batteries, such as those from Aquion Energy, alsocome to mind. As fast as the price of electricity from solar PVs has been dropping, we should not be surprised if the costs of solar-plus-storage or wind-plus-storage drop considerably faster.
There are other advantages implicit in adding storage to the power supply. One is that the power can be ramped up or down much faster than it can be with conventional approaches to equipment. Power demands on batteries and some other storage solutions can be ramped up or down in fractions of a second.
Indeed, the storage component moves us into a situation where solar and wind, with support from other types of renewable energy, can take on larger baseload power systems. Clearly, if utility-scale solar + storage = $92/MWh, it will always be less expensive than the $97 to $136 per MWh cost of nuclear power. It is competitive with power from coal. The only fossil fuel remaining in Lazard’s analysis that is clearly less expensive than solar-plus-storage is combined cycle natural gas, with a costrange of$48 to $78 MWh, and we have no guarantees those prices will last. And remember, this is not solar power alone, but solar with energy storage.
We seem to be moving into a new age, and it is not merely an age when the sun and wind provide the least expensive power we have. It is an age when the sun and the wind may replace baseload power altogether, not only as the least expensive solution, but as the best general solution. And we might come to that faster than we dreamed possible.
Scientists in the U.S. have identified an ominous trend in the Southern Ocean—the creation of enormous icebergs as rifts develop in the shelf ice many miles inland. And although three vast icebergs have broken from the Pine Island glacier in West Antarctica and drifted north in this century alone, researchers have only just worked out what has been going on.
Their first clue came from a telltale shadow in the south polar ice, caught by a NASA satellite and visible only while the sun was low in the sky, casting a long shadow.
It was the first sign of a fracture 20 miles inland, in 2013. Two years later, the rift became complete and the 580 sq km iceberg drifted free of the shelf.
Significant Collapse
“It’s generally accepted that it’s no longer a question of whether the West Antarctic Ice Sheet will melt—it’s a question of when,” said study leader Ian Howat, a glaciologist in the School of Earth Sciences at Ohio State University in the U.S.
“This kind of rifting behavior provides another mechanism for rapid retreat of these glaciers, adding to the probability that we may see significant collapse of West Antarctica in our lifetimes.”
The Pine Island glacier is grounded on continental bedrock below sea level, which means that warming ocean water could penetrate far inland beneath the shelf, without anyone being conscious of any change.
The first evidence of something unusual was a valley—the one highlighted by shadows visible only at a particular time and captured by NASA imagery—in the ice, where it had thinned. The valley was the first outward sign that ice was melting far below the surface.
The shelf ice plays an important role in slowing the progress of south polar glaciers: remove the shelf ice and the glacier flow accelerates.
The really troubling thing is that there are many of these valleys further up-glacier. If they are actually sites of weakness that are prone to rifting, we could potentially see more accelerated ice loss in Antarctica.
Antarctica is home to more than half the world’s fresh water. The Pine Island glacier and its neighbor and twin, the Thwaite glacier, are at the outer edge of an ice stream. In effect, they have “corked” the flow.
But West Antarctica is warming far more swiftly than the rest of the south polar region. And the calving of huge icebergs fuels researchers’ fear that, within 100 years, the entire West Antarctic ice sheet could collapse, with disastrous consequences for many coastal cities worldwide.
Sea ice hit record lows in November, EurekAlert, 6 Dec 16 UNIVERSITY OF COLORADO AT BOULDERUnusually high air temperatures and a warm ocean have led to a record low Arctic sea ice extent for November, according to scientists at the National Snow and Ice Data Center (NSIDC) at the University of Colorado Boulder. In the Southern Hemisphere, Antarctic sea ice extent also hit a record low for the month, caused by moderately warm temperatures and a rapid shift in circumpolar winds.
“It looks like a triple whammy–a warm ocean, a warm atmosphere, and a wind pattern all working against the ice in the Arctic,” said NSIDC director Mark Serreze.
Arctic sea ice extent averaged 9.08 million square kilometers (3.51 million square miles) for November, 1.95 million square kilometers (753,000 square miles) below the 1981 to 2010 long-term average for the month. Although the rate of Arctic ice growth was slightly faster than average, total extent actually decreased for a brief period in the middle of the month. The decrease in extent measured 50,000 square kilometers (19,300 square miles) and was observed mostly in the Barents Sea, an area of the Arctic Ocean north of Norway, Finland, and Eastern Russia.
NSIDC scientists said the decrease in extent is almost unprecedented for November in the satellite record; a less pronounced and brief retreat of 14,000 square kilometers (5,400 square miles) happened in 2013. November 2016 is now the seventh month this year to have hit a record low extent in the 38-year satellite monitoring period. The November extent was 3.2 standard deviations below the long-term average, a larger departure than observed in September 2012 when the Arctic summer minimum extent hit a record low………
In the Southern Hemisphere, sea ice surrounding the continent of Antarctica declined very quickly early in the month and set a record low. The average extent for November was 14.54 million square kilometers (5.61 million square miles), 1.81 million square kilometers (699,000 square miles) below the 1981 to 2010 average. This was more than twice the previous record departure from average set in November 1986 and was 5.7 standard deviations below the long-term average.
NSIDC scientists said that higher-than-average temperatures and a rapid shift in Antarctic circumpolar winds appear to have caused the rapid decline in Antarctic sea ice……..
NASA scientist and NSIDC affiliate scientist Walt Meier said, “The Arctic has typically been where the most interest lies, but this month, the Antarctic has flipped the script and it is southern sea ice that is surprising us.” https://www.eurekalert.org/pub_releases/2016-12/uoca-sih120616.php
EurekAlert, 13 Oct 16 Extreme Antarctica ice melt provides glimpse of ecosystem response to global climate change
PORTLAND STATE UNIVERSITY New research led by Portland State University glacier scientist Andrew Fountain reveals how a single warming event in Antarctica may be an indication of future ecosystem changes.
In the scientific paper, “The Impact of a Large-scale Climate Event on Antarctic Ecosystem Processes,” published in a special section Thursday in Bioscience, Fountain and his team detail the climate event and summarize the cascading ecological consequences over the last 15 years caused by a single season of intense melting in Antarctica between 2001 and 2002……..https://www.eurekalert.org/pub_releases/2016-10/psu-cfa101216.php
So how should we interpret this apparent backflip? In our paper published today in Nature Climate Change we review the latest science on Antarctica’s climate, and why it seems so confusing.
Antarctic surprises
First up, Antarctic climate records are seriously short.
The International Geophysical Year in 1957/58 marked the start of many sustained scientific efforts in Antarctica, including regular weather readings at research bases. These bases are mostly found on the more accessible parts of Antarctica’s coast, and so the network – while incredibly valuable – leaves vast areas of the continent and surrounding oceans without any data.
In the end, it took the arrival of satellite monitoring in the 1979 to deliver surface climate information covering all of Antarctica and the Southern Ocean. What scientists have observed since has been surprising.
The surface ocean around Antarctica has also mostly been cooling. This cooling masks a much more ominous change deeper down in the ocean, particularly near the West Antarctic Ice Sheet and the Totten glacier in East Antarctica. In these regions, worrying rates of subsurface ocean warming have been detected up against the base of ice sheets. There are real fears that subsurface melting could destabilise ice sheets, accelerating future global sea level rise.
In the atmosphere we see that some parts of the Antarctic Peninsula and West Antarctica are experiencing rapid warming, despite average Antarctic temperatures not changing that much yet.
In a rapidly warming world these Antarctic climate trends are – at face value – counterintuitive. They also go against many of our climate model simulations, which, for example, predict that Antarctica’s sea ice should be in decline.
Winds of change
The problem we face in Antarctica is that the climate varies hugely from year to year, as typified by the enormous swing in Antarctica sea ice over the past two years.
The changing westerlies may also help explain the seemingly unusual changes happening elsewhere in Antarctica.
The expansion of sea ice, particularly in the Ross Sea, may be due to the strengthened westerlies pushing colder Antarctic surface water northwards. And stronger westerlies may isolate Antarctica from the warmer subtropics, inhibiting continent-scale warming. These plausible explanations remain difficult to prove with the records currently available to scientists.
Australia’s unique climate position
The combination of Antarctica’s dynamic climate system, its short observational records, and its potential to cause costly heatwaves, drought and sea-level rise in Australia, mean that we can’t afford to stifle fundamental research in our own backyard.
Our efforts to better understand, measure and predict Antarctic climate were threatened this year by funding cuts to Australia’s iconic climate research facilities at the CSIRO. CSIRO has provided the backbone of Australia’s Southern Ocean measurements. As our new paper shows, the job is far from done.
A recent move to close Macquarie Island research station to year-round personnel would also have seriously impacted the continuity of weather observations in a region where our records are still far too short. Thankfully, this decision has since been reversed.
The nearly A$2 billion in new investment includes a new Australian icebreaking ship to replace the ageing Aurora Australis. This will bring a greater capacity for Southern Ocean research and the capability to push further into Antarctica’s sea ice zone.
Whatever the long-term trends in sea ice hold it is certain that the large year-to-year swings of Antarctica’s climate will continue to make this a challenging but critical environment for research.
If I just explain the facts, they’ll get it, right?
How NRDC will fight Trump’s attack on our environment.
NOW I AM BECOME DEATH, THE DESTROYER OF WORLDS (J. Robert Oppenheimer)
EVENTS
UK There is an opportunity to comment on the UK Advanced Boiling Water Reactor
(UK-ABWR) nuclear power station design before the process closes on 15
August. You will be able to do so at the link below: Hitachi (accessed) 27th July 2017 http://www.hitachi-hgne-uk-abwr.co.uk/make_a_comment.html
