The only thing more frightening than an advancing glacier may be one that is shrinking and raising sea levels round the world
Both the north pole and the south pole are situated in the middle of huge ice deserts which are melting around the edges under the influence of human activity. The difference that matters between them is that the ice of the Arctic floats: if it melted nothing much would happen to aggregate sea levels. The ice of Antarctica, like that of Greenland, rests on land. If it all were to melt, as it has done in the far distant past, sea levels could rise by as much as 60 metres. That is most unlikely to happen. What is possible, though, is that the smaller portion of the continent, west Antarctica, which is divided from the rest by a mountain range, could lose much of its ice. Even that would be catastrophic. A significant retreat in west Antarctica, as seems to be already under way, could raise sea levels by between one and three metres by the end of this century. Children now alive will see that happen across their lifetimes. That is what is meant by the urgency of global warming.
Previous surveys have concentrated on a few of the glaciers that are an obvious danger but the research released this week analysed satellite data covering the whole of the coastline of west Antarctica to reach its worrying conclusions. The problem is worsened by the shape of the seabed on which the glaciers now rest. It does not slope towards the deep ocean, but inwards, forming a bowl of which the far side is the mountain range that divides the continent. That means that the process of erosion will be working downhill as it moves inwards, with faster and less predictable results.
The present danger was discovered by measuring the thickness of the ice sheet from space and deducing from this the shape of the glacier beneath. This is much easier than knowing what to do. The contrast between the exquisite technological sophistication employed in the diagnosis of the problem and the lack of international coordination or political sophistication when it comes to solving it, illustrates the crisis of technological civilisation. As a species we have shown enough cleverness to disrupt the world’s climate, but may not have enough to remedy the damage that we’ve done. Things are of course made very much worse by the presence in the White House of an aggressively ignorant and anti-scienceadministration.
Predicting the future of these changes isn’t an exact science, which is one of the things which makes them so frightening, but neither is it entirely guesswork. Ignorance about the size of the threatened rise in sea levels is no excuse for inaction. We know it’s coming. We know it will be disruptive. We don’t know if it will be catastrophic. But the possibility must spur us into drastic action on fossil fuels. Keep them in the ground.
Antarctica retreating across the sea floor, EurekAlert , UNIVERSITY OF LEEDS , 3 April 18 Antarctica’s great ice sheet is losing ground as it is eroded by warm ocean water circulating beneath its floating edge, a new study has found.
Research by the UK Centre for Polar Observation and Modelling (CPOM) at the University of Leeds has produced the first complete map of how the ice sheet’s submarine edge, or “grounding line”, is shifting. Most Antarctic glaciers flow straight into the ocean in deep submarine troughs, the grounding line is the place where their base leaves the sea floor and begins to float.
Their study, published today in Nature Geoscience, shows that the Southern Ocean melted 1,463 km2 of Antarctica’s underwater ice between 2010 and 2016 – an area the size of Greater London.
The team, led by Dr Hannes Konrad from the University of Leeds, found that grounding line retreat has been extreme at eight of the ice sheet’s 65 biggest glaciers. The pace of deglaciation since the last ice age is roughly 25 metres per year. The retreat of the grounding line at these glaciers is more than five times that rate.
Why remote Antarctica is so important in a warming world The Conversation.Chris Fogwill, Professor of Glaciology and Palaeoclimatology, Keele University, Chris Turney, Professor of Earth Sciences and Climate Change, UNSW, Zoe Robinson, Reader in Physical Geography and Sustainability/Director of Education for Sustainability, Keele University
“……..What was once thought to be a largely unchanging mass of snow and ice is anything but. Antarctica holds a staggering amount of water. The three ice sheets that cover the continent contain around 70% of our planet’s fresh water, all of which we now know to be vulnerable to warming air and oceans. If all the ice sheets were to melt, Antarctica would raise global sea levels by at least 56m.
Where, when, and how quickly they might melt is a major focus of research. No one is suggesting all the ice sheets will melt over the next century but, given their size, even small losses could have global repercussions. Possible scenarios are deeply concerning: in addition to rising sea levels, meltwater would slow down the world’s ocean circulation, while shifting wind belts may affect the climate in the southern hemisphere.
In 2014, NASA reported that several major Antarctic ice streams, which hold enough water to trigger the equivalent of a one-and-a-half metre sea level rise, are now irreversibly in retreat. With more than 150m people exposed to the threat of sea level rise and sea levels now rising at a faster rate globally than any time in the past 3,000 years, these are sobering statistics for island nations and coastal cities worldwide.
An immediate and acute threat
Recent storm surges following hurricanes have demonstrated that rising sea levels are a future threat for densely populated regions such as Florida and New York. Meanwhile the threat for low-lying islands in areas such as the Pacific is immediate and acute.
Multiple factors mean that the vulnerability to global sea level rise is geographically variable and unequal, while there are also regional differences in the extremity of sea level rise itself. At present, the consensus of the IPPC 2013 report suggests a rise of between 40 and 80cm over the next century, with Antarctica only contributing around 5cm of this. Recent projections, however, suggest that Antarctic contributions may be up to ten times higher.Studies also suggest that in a world 1.5-2°C warmer than today we will be locked into millennia of irreversible sea level rise, due to the slow response time of the Antarctic ice sheets to atmospheric and ocean warming.
We may already be living in such a world. Recent evidence shows global temperatures are close to 1.5°C warmer than pre-industrial times and, after the COP23 meeting in Bonn in November, it is apparent that keeping temperature rise within 2°C is unlikely.
So we now need to reconsider future sea level projections given the potential global impact from Antarctica. Given that 93% of the heat from anthropogenic global warming has gone into the ocean, and these warming ocean waters are now meeting the floating margins of the Antarctic ice sheet, the potential for rapid ice sheet melt in a 2°C world is high.In polar regions, surface temperatures are projected to rise twice as fast as the global average, due to a phenomenon known as polar amplification. However, there is still hope to avoid this sword of Damocles, as studies suggest that a major reduction in greenhouse gases over the next decade would mean that irreversible sea level rise could be avoided. It is therefore crucial to reduce CO₂ levels now for the benefit of future generations, or adapt to a world in which more of our shorelines are significantly redrawn.
This is both a scientific and societal issue. We have choices: technological innovations are providing new ways to reduce CO₂ emissions, and offer the reality of a low-carbon future. This may help minimise sea level rise from Antarctica and make mitigation a viable possibility.
UNFROZEN IN TIME, Huffington Post, Video and Pictures: Tom Compagnoni | Words: Josh Butler, 1 December 17There’s a glacier in Antarctica so immense that, if it melted, would raise sea levels globally by 3.5 metres.
It’s melting. Right now.
“The facts around climate change are undeniable. It’s happening,” Australian glaciologist Ben Galton-Fenzi told The Huffington Post Australia. “The research we do now isn’t about trying to convince ourselves it’s real, because it’s irrefutable. What we’re trying to do is understand what the response time of the system is going to be into the future, so we can adapt to it.”
The Totten glacier is the biggest in east Antarctica. The glacier itself is around 120 kilometres long, 30 kilometres wide and drains some 538,000 square kilometres of the continent. That’s an area bigger than California. The ice is kilometres thick, but it’s melting at 70 metres a year in some spots. A study released in December reported warmer water was melting the Totten ice from below.
Galton-Fenzi and his small team will spend the next few months trying to work out exactly how fast the glacier is melting, gathering data to build better models to predict melt rates and how that will affect sea levels.
“The majority of the heat that has gone into the global climate system has gone into the ocean, about 90 percent over the last few decades of measurements,” he said. “The hypothesis is ocean temperatures around Antarctica will keep warming and drive the melting of the glaciers. If the glaciers flow faster, sea levels will rise, and that has profound implications for global civilisation.”……..“Climate change is a reality. There’s the whole debate around how we deal with it, and the work we do in Antarctica is influencing our ability to look forward and genuinely understand how much things are going to change,” Australian Antarctic Division director, Dr Nick Gales told HuffPost Australia from Hobart, the base of operations for the AAD.
“It is alarming. There is huge change going on there. The more we learn, the more we see change happening at rates faster than we predicted. It’s fundamentally important to support the science, communicate the science really well, and make sure the policy makers are aware of the science so they can take account of that in forming mitigation and adaptation strategies around the world.”
The AAD is the government body that administers Australian operations in Antarctica, from delivering workers and equipment to the continent, to selecting the research applications to be undertaken each season, to making sure the kitchen at Casey is well stocked with chocolate.
“When we started doing science in Antarctica, it was important and interesting because we were learning about things we simply didn’t know about.”
“Nowadays, the science is really critically important to what we do in the future.”
It’s critical to our wellbeing and our ability to understand what’s coming, and adapt and mitigate the effects. What about the droughts? Are they going to become more regular? What will happen to our low-lying areas and Pacific islands in relation to sea level rise? The science we do is critical for informing that.”This season, the AAD will support almost 100 projects in Antarctica and the Southern Ocean. More than 500 expeditioners will make their way down each year for major “season-defining” projects such as Galton-Fenzi’s Totten glacier work, and smaller-scale operations. Gales said around two-thirds of the Australian-led research in Antarctica is related to climate science.
It is a continent almost entirely covered by ice, the largest ice sheet in the world and the planet’s largest single reserve of fresh water. It’s almost entirely untouched by humans, uninhabited but for the research teams (and a whole lot of amazing animal life, as we soon discovered); a continent literally devoted to science.
The 1959 Antarctic treaty, signed by the 12 countries which had been active in Antarctica — Argentina, Australia, Belgium, Chile, France, Japan, New Zealand, Norway, Russia, South Africa, the United Kingdom and United States — agreed to set aside territorial claims and enshrine the continent as a place for peace, science and international collaboration. Scientists work together, sharing resources, manpower and findings, for the good of humanity under this treaty, which states:
– Antarctica shall be used for peaceful purposes only (Art. I)
– Freedom of scientific investigation in Antarctica and cooperation toward that end … shall continue (Art. II).
– Scientific observations and results from Antarctica shall be exchanged and made freely available (Art. III).
“It’s unique. It’s extraordinary that, in a place like that, the world can agree to set aside differences and focus on those really important issues,” Gales said………
Johnstone and Black are cutting through the frozen sea ice for experiments on ocean acidification. As the Earth continues to emit carbon dioxide, the oceans soak up a large percentage of that extra CO2; around 30 percent, Black said.
Rob King, an AAD biologist based in Hobart, said around eight billion tonnes of CO2 is going into oceans each year.
“It increases the acidity of the ocean and lowers the pH. The global ocean average is about 8.2pH, and we’re expecting by the year 2100 with the current emissions scenarios we have, the pH will drop to 7.8,” Black said.
That’s a massive change for the ocean, with the water becoming far more acidic. That’s bad news for many tiny organisms and plankton that make up the bottom of the oceanic food chain, upon which larger creatures like penguins, fish, dolphins, seals, sharks and whales depend. Black and Johnstone have planted tiny chambers on the ocean floor to simulate how the water and the organisms will react to more acidic waters. They will also collect water and loads of these tiny organisms for experiments in the lab.
“As we acidify the water, anything with a calcium carbonate structure in its shell, like shellfish, pteropods and other organisms, will actually have trouble forming that shell and maintaining it,” Black said.
“When we look at the relative biomass of different organisms, we get about 600 million tonnes of phytoplankton down here. That’s the most biomass of any organism in the Southern Ocean. While they seem small and insignificant, they are the most important part of the ecosystem. Any change in that under climate change conditions will have flow on effects up the food chain.”……….
“Under the sea ice you’ve got a really stable environment. It’s always the same temperature, even though it’s a really harsh temperature of minus 1.85C all year, but it doesn’t vary much so they only have to adapt to one temperature,” the marine biologist said.’
“There’s very little current under here, because for 10 months of the year, there’s a covering of sea ice. They don’t have to deal with big tidal currents or waves or storms or wind action, or temperature changes. The conditions are relatively stable through the year.”
The word ‘frozen’ is often used to denote something which has stopped; static, not moving. It is synonymous with lifelessness, death, a barren wasteland. Antarctica is a frozen continent, but it is by no means dead. It grows and shrinks like a living organism. With the yearly melt and refreeze, as the continent effectively doubles in size during the winter as sea water becomes ice, it is arguably the most alive continent on Earth. The life that exists down here — human, animal and plant alike — is some of the hardiest, most resilient on the planet. It’s an entire continent devoted to peace and science, to work for the betterment of the entire planet.
University of Melbourne paper combines latest understanding on Antarctica and current emissions projection scenarios, Guardian, Michael Slezak, Coastal cities around the world could be devastated by 1.3m of sea level rise this century unless coal-generated electricity is virtually eliminated by 2050, according to a new paper that combines the latest understanding of Antarctica’s contribution to sea level rise and the latest emissions projection scenarios.
It confirms again that significant sea level rise is inevitable and requires rapid adaptation. But, on a more positive note, the work reveals the majority of that rise – driven by newly recognised processes on Antarctica – could be avoided if the world fulfils its commitment made in Paris to keep global warming to “well below 2C”.
But that paper only examined the impact of Antarctica on sea level rise, ignoring other contributions, and didn’t examine the details of what measures society needed to take to avoid those impacts.
The new paper by Alexander Nauels from the University of Melbourne and colleagues uses simplified physical models that allowed them to explore all known contributions to sea level rise, and pair them with the new generation of emissions scenarios which the Intergovernmental Panel on Climate Change (IPCC) will use in the next set of reports.
They found that if nothing is done to limit carbon pollution, then global sea levels will rise by an estimated 1.32m. That is 50% more than was previously thought, with the IPCC’s AR5 report suggesting 85cm was possible by the end of the century.
But the extra contribution from Antarctica would not kick in if warming was kept at less than 1.9C above preindustrial levels, the researchers found. Temperatures above that threshold risked triggering the additional processes in Antarctica identified in the 2016 paper, causing much greater sea level rise.
“The 1.5C limit in the Paris Agreement is a much safer bet to avoid this additional contribution than only achieving 2C,” Nauels said.
But that paper only examined the impact of Antarctica on sea level rise, ignoring other contributions, and didn’t examine the details of what measures society needed to take to avoid those impacts.
The new paper by Alexander Nauels from the University of Melbourne and colleagues uses simplified physical models that allowed them to explore all known contributions to sea level rise, and pair them with the new generation of emissions scenarios which the Intergovernmental Panel on Climate Change (IPCC) will use in the next set of reports.
Under all scenarios we are going to have to adapt
They found that if nothing is done to limit carbon pollution, then global sea levels will rise by an estimated 1.32m. That is 50% more than was previously thought, with the IPCC’s AR5 report suggesting 85cm was possible by the end of the century.
But the extra contribution from Antarctica would not kick in if warming was kept at less than 1.9C above preindustrial levels, the researchers found. Temperatures above that threshold risked triggering the additional processes in Antarctica identified in the 2016 paper, causing much greater sea level rise.
“The 1.5C limit in the Paris Agreement is a much safer bet to avoid this additional contribution than only achieving 2C,” Nauels said.
Those scenarios suggested coal could only make up 5% of the world’s energy mix by 2050 if sea level rise is to be limited to about half a metre.
Similarly, those scenarios suggested a global carbon price would have to be well over US$100 per tonne, since at that cost, sea level would rise by 65cm by 2100.
John Church, a leading sea level rise expert from the University of New South Wales who was co-convening lead author of the chapter on sea level in the third and fifth IPCC Assessment Reports, told the Guardian the work was further confirmation that the world needed to prepare now for substantial sea level rises.
“Under all scenarios we are going to have to adapt,” Church said. “We cannot stop all sea level rise.”
He said the research community was not in consensus yet about the accelerated contribution of Antarctica to sea level rise, identified in the 2016 paper and modelled in this study, but examining the implications of those findings was still important.
DeConto, the lead author of the landmark paper from 2016, said it was important to recognise the good news in his original findings and this extension of that work.
“In the aggressive mitigation pathways, where we assume that the global community gets its act together and we reduce emissions, it’s a much rosier picture. There’s a much reduced risk of dramatic sea level rise from Antarctica,” he told the Guardian. “This study fully reinforces that.”
Nauels said his team’s work assumed that Antarctica would contribute to sea level rise as was suggested by the 2016 paper by DeConto, but more work was needed to confirm those findings.
“We still have to find out what’s going on in Antarctica,” he told the Guardian. “We can’t base all future sea level rise projects on just one paper. And the Antarctic ice sheet community are frantically working on the new insights.”
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.”
