With help from floating data-collectors, a new study reveals the impact greenhouse gas emissions and ozone depletion are having on the Southern Ocean. Inside Climate News, Sabrina Shankman SEP 24, 2018 The Southern Ocean around Antarctica is warming at an alarming rate—twice that of the rest of the world’s oceans. Now, researchers have developed more powerful evidence pointing to the human causes.
Antarctic ocean heating up – caused by greenhouse gas emissions and ozone depletion
What’s Causing Antarctica’s Ocean to Heat Up? New Study Points to 2 Human Sources
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Sea levels could rise by up to 30 feet, due to Antarctic melting
At this rate, Earth risks sea level rise of 20 to 30 feet, historical analysis shows New research finds that a vast area of Antarctica retreated when Earth’s temperatures weren’t much warmer than they are now, WP Chris Mooney, September 20 2018
Temperatures not much warmer than the planet is experiencing now were sufficient to melt a major part of the East Antarctic ice sheet in Earth’s past, scientists reported Wednesday, including during one era about 125,000 years ago when sea levels were as much as 20 to 30 feet higher than they are now.
“It doesn’t need to be a very big warming, as long as it stays 2 degrees warmer for a sufficient time, this is the end game,” said David Wilson, a geologist at Imperial College London and one of the authors of the new research, which was published in Nature. Scientists at institutions in Australia, New Zealand, Japan and Spain also contributed to the work.
The research concerns a little-studied region called the Wilkes Subglacial Basin, which is roughly the size of California and Texas combined and contains more than 10 feet of potential sea-level rise. Fronted by three enormous glaciers named Cook, Mertz and Ninnis, the Wilkes is known to be vulnerable to fast retreat because the ice here is not standing on land and instead is rising up from a deep depression in the ocean floor.
Moreover, that depression grows deeper as you move from the current icy coastline of the Wilkes farther inland toward the South Pole, a downhill slope that could facilitate rapid ice loss.
What the new science adds is that during past warm periods in Earth’s history, some or all of the ice in the Wilkes Subglacial Basin seems to have gone away. That’s an inference researchers made by studying the record of sediments in the seafloor just off the coast of the current ice front……..
Humans have caused about 1 degree Celsius (1.8 degrees Fahrenheit) of warming above the preindustrial planetary temperatures experienced before the year 1880 or so. The world has pledged to avoid a warming above 2 degrees Celsius, and even hopes to hold the warming to 1.5 degrees, but current promises made by countries are not nearly enough to prevent these outcomes.
n other words, we are already on a course that could heat the planet enough to melt some or all of the Wilkes Basin.
“We say 2 degrees beyond preindustrial, and we’re already beyond preindustrial,” Wilson said. “So this is potentially the kinds of temperatures we could see this century.”
The study cannot reveal, however, just how quickly ice emptied out of the Wilkes Basin. The past warm periods in question are thought to have been driven by slight variations in Earth’s orbit as it rotates around the sun, leading to stronger summer heat. That warmth was maintained for thousands of years.
…….. The new research “contributes to the mounting pile of evidence that East Antarctica is not as stable as we thought,” Isabella Velicogna, a glaciologist at the University of California at Irvine, said by email. Velicogna was not directly involved in the paper…….https://www.washingtonpost.com/energy-environment/2018/09/20/antarctica-warming-could-fuel-disastrous-sea-level-rise-study-finds/?utm_term=.7c426ea2a985
New Zealand’s Antarctic veterans are advised on effects of their exposure to nuclear radiation
New Zealand warns its Antarctic veterans about radiation risks from leaky US Navy reactor https://www.stripes.com/news/new-zealand-warns-its-antarctic-veterans-about-radiation-risks-from-leaky-us-navy-reactor-1.533546 By SETH ROBSON | STARS AND STRIPES June 19, 2018
The New Zealand government is warning personnel who worked in Antarctica in the 1960s and ‘70s about radiation from a leaky U.S. Navy reactor.
Alerts were posted online by the New Zealand Defence Force, Antarctica New Zealand and other government entities in January and reported by local media last month.
They advise people to contact the New Zealand Office of Radiation Safety or their doctor if they think they may have been exposed to radiation from the reactor used to power McMurdo Station, Antarctica, from 1962 to 1979.
The U.S. Department of Defense has assessed the risk of radiation exposure for those who worked near the power plant as low.
However, the Department of Veterans Affairs ruled in November that retired Navy veteran James Landy’s “esophageal, stomach, liver, and brain and spine cancers, [were] incurred in active duty service.”
Landy worked at McMurdo as a C-130 flight engineer from 1970 to 1974 and from 1977 to 1981 before dying at age 63 in 2012, said his widow, Pam Landy.
He had pain in his kidneys and went to the doctor and they sent him to an oncologist who said he had cancer from radiation exposure,” she said in a phone interview Monday from her home in Pensacola, Fla.
Veterans who served in Antarctica should have been warned about the radiation risk, Pam Landy said.
“The government knew that thing was there. If they had given people a heads up he could have been diagnosed early and might have a shot at being alive,” she said. “I got a payout from the VA, but it’s a pittance compared to a life.”
The McMurdo reactor had many malfunctions, but personnel might also have been exposed during its decommissioning when soil and rock from the site was trucked through the base to be shipped off the continent, she said.
Peter Breen, 64, was a New Zealand Army mechanic about 2 miles from McMurdo at Scott Base from 1981 to 1982. Rock and soil from the reactor site was taken to a wharf in open trucks, and Breen fears he could have been exposed to contaminated dust blown by the wind or on ice harvested from nearby cliffs.
He’s campaigning for New Zealand Antarctic veterans to be recognized with a medal and offered health checks.
“It is not compensation that guys are after,” he said in a phone interview from his home in Tauranga, New Zealand. “They want a health-check program.”
robson.seth@stripes.com
Twitter: @SethRobson1
Faster global warming predicted, with new Antarctic study
Climate Central By Mikayla Mace, Arizona Daily Star 10 June 18
A group of scientists, including one from the University of Arizona, has new findings suggesting Antarctica’s Southern Ocean — long known to play an integral role in climate change — may not be absorbing as much pollution as previously thought.
To reach their contradictory conclusion, the team used state-of-the-art sensors to collect more data on the Southern Ocean than ever before, including during the perilous winter months that previously made the research difficult if not impossible.The old belief was the ocean pulled about 13 percent of the world’s carbon dioxide — a greenhouse gas that contributes to climate change — out of the atmosphere, helping put the brakes on rising global temperatures.
Some oceanographers suspect that less CO2 is being absorbed because the westerlies — the winds that ring the southernmost continent — are tightening like a noose. As these powerful winds get more concentrated, they dig at the water, pushing it out and away.
Water from below rises to take its place, dragging up decaying muck made of carbon from deep in the ocean that can then either be released into the atmosphere in the form of CO2 or slow the rate that CO2 is absorbed by the water. Either way, it’s not good.
The Southern Ocean is far away, but “for Arizona, this is what matters,” said Joellen Russell, the University of Arizona oceanographer and co-author on the paper revealing these findings. “We don’t see the Southern Ocean, and yet it has reached out the icy hand.”
Oceans, rivers, lakes and vegetation can moderate extreme changes in temperature. Southern Arizona has no such buffers, leaving us vulnerable as average global temperatures march upward.
“Everybody asks, ‘Why are you at the UA?’” Russell said about studying the Southern Ocean from the desert at the University of Arizona. She said the research is important to Arizona and the university supports her work.
…….. scientists know less about the Southern Ocean than the rest of the world’s oceans. What they do know is mostly limited to surface CO2 levels in the summer, when it’s safer to take measurements by ships with researchers aboard. Shipboard sensors that directly measure CO2 are the accepted scientific standard in these types of studies.
Understanding CO2 levels within the air, land and sea and how it is exchanged between the three is necessary for making more accurate future climate predictions.
To fill the gap in knowledge, Russell and her team have deployed an array of cylindrical tanks, called floats, that collect data on carbon and more in the Southern Ocean year-round. Russell leads the modeling component of this project called Southern Ocean Carbon and Climate Observations and Modeling, or SOCCOM.
The floats drift 1,000 meters below the surface. Every 10 days, they plunge a thousand meters deeper, then bob up to the surface before returning to their original depth.
For three years, 35 floats equipped with state-of-the-art sensors the size of a coffee cup have been collecting data along the way and beaming it back to the researchers, like Russell in Tucson. Within hours, the data is freely available online.
They measure ocean acidity, or pH, and other metrics to understand the biogeochemistry of the elusive ocean, but not without controversy.
Making a splash
Alison Gray, an oceanographer at the University of Washington, is the lead author on the study. She said there are two reasons the study may contradict what has previously been thought of about the Southern Ocean: The lack of winter-time observations at the ocean by other researchers and the fact that ocean carbon levels might vary throughout the year.
So while SOCCOM is making it possible to get more data than ever before, others question her nontraditional methods. ………http://www.climatecentral.org/news/antarctic-ocean-discovery-warns-of-faster-global-warming-21865
Thorium nuclear power – not so great, really
Today, advocates of thorium typically point to a variety of advantages over uranium. These include fail-safe reactor operation, because most thorium reactor designs are incapable of an explosion or meltdown, as was seen at Chernobyl or Fukushima. Another is resistance to weapons proliferation, because thorium reactors create byproducts that make the fuel unsuitable for use in nuclear weapons.Other advantages include greater abundance of natural reserves of thorium, less radioactive waste and higher utilisation of fuel in thorium reactors. Thorium is often cast as “good nuclear”, while uranium gets to carry the can as “bad nuclear”.
Not so different
While compelling at first glance, the details reveal a somewhat more murky picture. The molten salt architecture which gives certain thorium reactors high intrinsic safety equally applies to proposed fourth-generation designs using uranium. It is also true that nuclear physics technicalities make thorium much less attractive for weapons production, but it is by no means impossible; the USA and USSR each tested a thorium-based atomic bomb in 1955.
Other perceived advantages similarly diminish under scrutiny. There is plenty of uranium ore in the world and hence the fourfold abundance advantage of thorium is a moot point. Producing less long-lived radioactive waste is certainly beneficial, but the vexed question remains of how to deal with it.
Stating that thorium is more efficiently consumed is the most mischievous of the claimed benefits. Fast-breeder uranium reactors have much the same fuel efficiency as thorium reactors. However, they weren’t economic as the price of uranium turned out to rather low.
Global warming is melting Antarctic ice from below
Warming oceans melting Antarctic ice shelves could accelerate sea level rise, Guardian, John Abraham, 9 May 18, “……With global warming, both of the poles are warming quite quickly, and this warming is causing ice to melt in both regions. When we think of ice melting, we may think of it melting from above, as the ice is heated from the air, from sunlight, or from infrared energy from the atmosphere. But in truth, a lot of the melting comes from below. For instance, in the Antarctic, the ice shelves extend from the land out over the water. The bottom of the ice shelf is exposed to the ocean. If the ocean warms up, it can melt the underside of the shelf and cause it to thin or break off into the ocean.
A new study, recently published in Science Advances, looked at these issues. One of the goals of this study was to better understand whether and how the waters underneath the shelf are changing. They had to deal with the buoyancy of the waters. We know that the saltier and colder water is, the denser it is.
Around Antarctica, water at the ocean surface cools down and becomes saltier. These combined effects make the surface waters sink down to the sea floor. But as ice melt increases, fresh water flows into the ocean and interrupts this buoyancy effect. This “freshening” of the water can slow down or shut down the vertical mixing of the ocean. When this happens, the cold waters at the surface cannot sink. The deeper waters retain their heat and melt the ice from below.
The study incorporated measurements of both temperature and salinity (saltiness) at three locations near the Dalton Iceberg Tongue on the Sabrina Coast in East Antarctica. The measurements covered approximately an entire year and gave direct evidence of seasonal variations to the buoyancy of the waters. The researchers showed that a really important component to water-flow patterns were ‘polynyas.’ These are regions of open water that are surrounded by ice, typically by land ice on one side and sea ice on the other side.
When waters from the polynya are cold and salty, the waters sink downwards and form a cold curtain around the ice shelf. However, when the waters are not salty (because fresh water is flowing into the polynya), this protective curtain is disrupted and warm waters can intrude from outside, leading to more ice melt.
Based on this study, we may see increased ice loss in the future – sort of a feedback loop. That concerns us because it will mean more sea level rise (which is already accelerating), and more damage to coastal communities. I asked the lead author, Alesandro Silvano about this work:
We found that freshwater from melting ice shelves is already enough to stop formation of cold and salty waters in some locations around Antarctica. This process causes warming and freshening of Antarctic waters. Ocean warming increases melting of the Antarctic Ice Sheet, causing sea level to rise. Freshening of Antarctic waters weakens the currents that trap heat and carbon dioxide in the ocean, affecting the global climate. In this way local changes in Antarctica can have global implications. Multiple sources of evidence exist now to show that these changes are happening. However, what will happen in Antarctica in the next decades and centuries remains unclear and needs to be understood.
This is just another reason to take scientists seriously and act to slow down climate change before it is too late. https://www.theguardian.com/environment/climate-consensus-97-per-cent/2018/may/09/global-warming-is-melting-antarctic-ice-from-below
Drastic action on fossil fuels is needed, as the Poles melt – with unpredictable consequences
The Guardian view on Antarctica: the worrying retreat of the ice https://www.theguardian.com/commentisfree/2018/apr/05/the-guardian-view-on-antarctica-the-worrying-retreat-of-the-ice Editorial
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.
Warm water underneath Antarctica’s great ice sheet is eroding it
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.
The biggest changes were seen in West Antarctica, where more than a fifth of the ice sheet has retreated across the sea floor faster than the pace of deglaciation……….https://www.eurekalert.org/pub_releases/2018-04/uol-ara032918.php
Antarctica – so remote, but so significant in climate science
Why remote Antarctica is so important in a warming world The Conversation.Chris Fogwill, Professor of Glaciology and Palaeoclimatology, Keele University, Professor of Earth Sciences and Climate Change, UNSW, 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.
An immense glacier is melting, in Antarctica
UNFROZEN IN TIME, Huffington Post, Video and Pictures: Tom Compagnoni | Words: Josh Butler, 1 December 17 There’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.
It’s alive with purpose………. http://stories.huffingtonpost.com.au/antarctica/
Stop coal power by 2050- or sea level will rise by 1.3m – new report
Sea levels to rise 1.3m unless coal power ends by 2050, report says https://www.theguardian.com/environment/2017/oct/26/sea-levels-to-rise-13m-unless-coal-power-ends-by-2050-report-says
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”.
In 2016, Robert DeConto from the University of Massachusetts Amherst revealed that Antarctica could contribute to massive sea level rise much earlier than thought, suggesting ice sheet collapse would occur sooner and identifying a new process where huge ice cliffs would disintegrate.
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.
In 2016, Robert DeConto from the University of Massachusetts Amherst revealed that Antarctica could contribute to massive sea level rise much earlier than thought, suggesting ice sheet collapse would occur sooner and identifying a new process where huge ice cliffs would disintegrate.
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.”
Beneath Antarctica’s ice, 91 previously unknown volcanoes have been found
Another climate-change nightmare: 91 new volcanoes beneath Antarctica’s ice, WP , ow 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.
But he laid out a worst-case scenario in which lava managed to melt through a glacier, and warm ocean water seeped into the hole, and the whole system began melting even faster, potentially unleashing vast magmatic forces beneath the ice. https://www.washingtonpost.com/news/speaking-of-science/wp/2017/08/15/another-climate-change-nightmare-dozens-of-volcanoes-beneath-antarcticas-thinning-ice/?utm_term=.fe9ede7c33c3
Stability of East Antarctic ice sheet, even if western ice sheet melts
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.
Some Antarctic glaciers not showing the effects of climate change
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.
Huge iceberg breaks away from Larsen C ice shelf in Antarctica
Larsen C: Giant iceberg breaks away from ice shelf in Antarctica, http://www.abc.net.au/news/2017-07-12/huge-iceberg-breaks-away-from-antarctica-larsen-c-shelf/8703238 One of the biggest icebergs on record has broken away from Antarctica, scientists have said, creating an extra hazard for ships around the continent as it breaks up. What happens now Antarctica’s ice shelf has cracked?
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.”
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