Slowing ocean current caused by melting Antarctic ice could have drastic climate impact, study says
The Southern Ocean overturning circulation has ebbed 30% since the 90s, CSIRO scientist claims, leading to higher sea levels and changing weather
Donna Lu, Guardian, 26 May 23
A major global deep ocean current has slowed down by approximately 30% since the 1990s as a result of melting Antarctic ice, which could have critical consequences for Earth’s climate patterns and sea levels, new research suggests.
Known as the Southern Ocean overturning circulation, the global circulation system plays a key role in influencing the Earth’s climate, including rainfall and warming patterns. It also determines how much heat and carbon dioxide the oceans store.
Scientists warn that its slowdown could have drastic impacts, including increasing sea levels, altering weather patterns and depriving marine ecosystems of vital nutrients.
“Changes in the overturning circulation are a big deal,” said the study’s co-author, Dr Steve Rintoul, an oceanographer and expert on the Southern Ocean at the Australian government’s Commonwealth Scientific and Industrial Research Organisation (CSIRO)
It’s something that is a concern because it touches on so many aspects of the Earth, including climate, sea level, and marine life.”
The finding comes months after modelling, which Rintoul was involved in, that predicted a 40% slowdown in the circulation by 2050.
“The model projections of rapid change in the deep ocean circulation in response to melting of Antarctic ice might, if anything, have been conservative,” Rintoul said. “We’re seeing changes have already happened in the ocean that were not projected to happen until a few decades from now.”
………………………………………….. The study looked specifically at changes in overturning circulation in the Australian Antarctic basin, but the researchers believe a “circumpolar slowdown” is occurring.
………………………..
“We expect in the longer term that while there will be ups and downs related to sea ice formation, the overall trend is that Antarctica is losing more ice, is melting more, and that will gradually slow down this overturning circulation.
“Unless we act soon we will commit ourselves to changes that we’d really rather avoid,” he said. “We need to act to reduce emissions and we need to do everything we can as fast as we can.”
The study, whose first author is Kathryn Gunn of the CSIRO and the University of Southampton, was published in the journal Nature Climate Change. https://www.theguardian.com/science/2023/may/25/slowing-ocean-current-caused-by-melting-antarctic-ice-could-have-drastic-climate-impact-study-says
Maori workers exposed to radiation in cleaning up USA’s failed nuclear reactor in Antarctica
Detour: Antarctica – Kiwis ‘exposed to radiation’ at Antarctic power plant, https://www.nzherald.co.nz/travel/detour-antarctica-kiwis-exposed-to-radiation-at-antarctic-power-plant/NY5WTQ72JF4OFUW4F35ZSUCB6U/ 8 Jan, 2022 By Thomas Bywater, Thomas Bywater is a writer and digital producer for Herald Travel
In a major new Herald podcast series, Detour: Antarctica, Thomas Bywater goes in search of the white continent’s hidden stories. In this accompanying text series, he reveals a few of his discoveries to whet your appetite for the podcast. You can read them all, and experience a very special visual presentation, by clicking here. To follow Detour: Antarctica, visit iHeartRadio, or wherever you get your podcasts.
The Waitangi Tribunal will consider whether NZ Defence Force personnel were appropriately warned of potential exposure to radiation while working at a decommissioned nuclear reactor in Antarctica.
It’s among a raft of historic claims dating from 1860 to the present day before the Military Veterans Inquiry.
After an initial hearing in 2016, the Waitangi Tribunal last year admitted the Antarctic kaupapa to be considered alongside the other claims.
“It’s been a bloody long journey,” said solicitors Bennion Law, the Wellington firm representing the Antarctic claimants.
Between 1972 and the early 1980s, more than 300 tonnes of radioactive rubble was shipped off the continent via the seasonal resupply link.
Handled by US and New Zealand personnel without properly measuring potential exposure, the submission argues the Crown failed in its duty of care for the largely Māori contingent, including NZ Army Cargo Team One.
“This failure of active protection was and continues to be in breach of Te Tiriti o Waitangi,” reads the submission.
The rubble came from PM3A, a portable nuclear power unit on Ross Island, belonging to the US Navy. Decommissioned in 1972, its checkered 10-year operating history led it to be known as ‘Nukey Poo’ among base inhabitants. After recording 438 operating errors it was shut off for good.
Due to US obligations to the Antarctic Treaty, nuclear waste had to be removed.
Peter Breen, Assistant Base Mechanic at New Zealand’s Scott Base for 1981-82, led the effort to get similar New Zealand stories heard.
He hopes that NZDF personnel involved in the cleanup of Ross Island might get medallic recognition “similar to those who were exposed at Mururoa Atoll”. Sailors were awarded the Special Service Medal Nuclear Testing for observing French bomb sites in the Pacific in 1973, roughly the same time their colleagues were helping clear radioactive material from Antarctica.
A public advisory regarding potential historic radiation exposure at McMurdo Station was published in 2018.
Since 1975 the Waitangi Tribunal has been a permanent commission by the Ministry of Justice to raise Māori claims relating to the Crown’s obligations in the Treaty of Waitangi.
The current Military Veterans’ Kaupapa includes hearings as diverse as the injury of George Nepata while training in Singapore, to the exposure of soldiers to DBP insecticides during the Malayan Emergency.
Commenced in 2014 in the “centenary year of the onset of the First World War” the Māori military veterans inquiry has dragged on to twice the duration of the Great War.
Of the three claimants in the Antarctic veterans’ claim, Edwin (Chaddy) Chadwick, Apiha Papuni and Kelly Tako, only Tako survives.
“We’re obviously concerned with time because we’re losing veterans,” said Bennion Law.
Detour: Antarctica is a New Zealand Herald podcast. You can follow the series on iHeartRadio, Apple Podcasts, Spotify or wherever you get your podcasts.
Antarctica’s melting ice sheet could retreat much faster than previously thought
Antarctica’s melting ice sheet could retreat much faster than previously
thought, new research suggests. The evidence comes from markings on the
seafloor off Norway that record the pull-back of a melting European ice
sheet thousands of years ago.
Today, the fastest withdrawing glaciers in
Antarctica are seen to retreat by up to 30m a day. But if they sped up, the
extra melt water would have big implications for sea-level rises around the
globe. Ice losses from Antarctica caused by climate change have already
pushed up the surface of the world’s oceans by nearly 1cm since the 1990s.
The researchers found that with the Norwegian sheet, the maximum retreat
was more than 600m a day.
BBC 5th April 2023
The world returns to an era of nuclear angst
Russia’s suspension of its arms control treaty with the US augurs a new period of military deterrence, arms races and instability
EL PAIS, ÓSCAR GUTIÉRREZ, Madrid – FEB 27, 2023
Dmitry Medvedev is currently the deputy chairman of the Security Council of the Russian Federation (SCRF), a consultative body that supports Russian President Vladimir Putin’s decision-making on national security affairs. In April 2010, when the United States and Russia signed the New Strategic Arms Reduction Treaty (New START) in Prague, limiting the nuclear offensive capabilities of both countries, the man in charge in Moscow, at least on paper, was Medvedev, then the president of the country. In late February, Putin suspended the treaty that Obama and Medvedev signed almost 13 years ago. At the New START signing ceremony, Medvedev said, “This will turn a new page for cooperation between our two countries and will create safer conditions for life here and around the world.” Not anymore.
Medvedev is one of the best examples of how nuclear security has changed since the Cold War between the US and Russia. He now fervently supports suspending the treaty he signed in 2010
and said in a Telegram post, “If the US intends to defeat Russia [by providing military support to Ukraine], then we are on the brink of a global conflict. We have the right to defend ourselves with any weapon, including nuclear ones.”
EL PAÍS consulted four arms control and security policy experts on the consequences of Putin’s suspension of the New START treaty. They all concurred that both countries had been complying with limits on warheads, missiles and delivery systems and felt that controlling such weapons would become complicated and potentially lead to a new arms race. Moscow’s move is an attempt to curb Western support for Ukraine, and without New START, there will be more uncertainty, instability and potential nuclear miscalculations. These same words and scenarios defined the Cold War geopolitical tension that dominated US-Russian relations for 40 years after World War II.
“Without the treaty, [the US and Russia] can do whatever they want,” said Olga Oliker, an expert on Russian and Ukrainian security policy for the International Crisis Group. “They can build whatever strategic offensive weapons they feel like and can afford. They won’t be able to verify what the other is or isn’t doing. They will still have intelligence-collecting capabilities but not the inspections, data exchanges and consultations to ensure compliance. Theoretically, they could deceive each other more easily.” Oliker believes the most significant risk in suspending the treaty lies in the potential “misunderstandings” arising from a lack of information.
New START limits the number of immediately deployable nuclear weapons owned by the US and Russia, which account for 90% of the world’s nuclear arsenal. They can only have a maximum of 1,550 deployed warheads and 700 long-range missile delivery systems between ground launchers, submarines and bombers. According to the US State Department, as of September 2022, both countries were below those numbers. It was a drastic reduction compared to the 1991 treaty Ronald Reagan and Mikhail Gorbachev signed. New START also initiated a compliance mechanism that permitted up to 18 inspections a year, regular information exchange and a monitoring commission, all of which are now suspended.
Non-compliance with inspections
Todd Sechser is a professor at the University of Virginia (USA) and a scholar at the Carnegie Endowment for International Peace. “The treaty is important not only because it limits the number of strategic nuclear warheads,” said Sechser, “but because it provides a way for the two countries to build trust. This move undermines that trust.” ……………………………………………………………………….. more https://english.elpais.com/international/2023-02-27/the-world-returns-to-an-era-of-nuclear-angst.html—
‘Extreme situation’: Antarctic sea ice hits record low
Damian Carrington 16 Feb 23
https://www.theguardian.com/world/2023/feb/15/antarctic-sea-ice-hits-record-low-climate-crisis
The area of sea ice around Antarctica has hit a record low, with scientists reporting “never having seen such an extreme situation before”. The ice extent is expected to shrink even further before this year’s summer melting season ends.
The impact of the climate crisis in melting sea ice in the Arctic is clear in the records that stretch back to 1979. Antarctic sea ice varies much more from year to year, which has made it harder to see an effect from global heating.
However, “remarkable” losses of Antarctic sea ice in the last six years indicate that the record levels of heat now in the ocean and related changes in weather patterns may mean that the climate crisis is finally manifesting in the observations.
Scientists were already very concerned about Antarctic ice. Climate models suggested as far back as 2014 that the giant West Antarctic Ice Sheet (WAIS), which sits on the continent, was doomed to collapse due to the levels of global heating already seen then.
The increasing loss of sea ice exposes ice sheets and their glaciers to waves that accelerate their disintegration and melting, researchers warned. A recent study estimated that the WAIS would be tipped into gradual collapse – and four metres of sea level rise – with a global temperature rise as low as 1C, a point already passed.
“I have never seen such an extreme, ice-free situation here before,” said Prof Karsten Gohl, from the Helmholtz Centre for Polar and Marine Research in the Alfred Wegener Institute, Germany, and who first visited the region in 1994.
Gohl, on board the research vessel Polarstern in Antarctica, said: “The continental shelf, an area the size of Germany, is now completely ice-free. It is troubling to consider how quickly this change has taken place.”
Prof Christian Haas, also at the Helmholtz Centre, said: “The rapid decline in sea ice over the past six years is quite remarkable, since the ice cover hardly changed at all in the 35 years before.”
Scientists at the National Snow and Ice Data Center in the US have also said a new record low has been set. They said Antarctic sea ice extent fell to 1.91m square kilometres on 13 February, below the previous record set on 25 February 2022.
Sea ice melts away in the Antarctic summer before starting to grow again as autumn arrives. “In past years, the annual minimum has occurred between 18 February and 3 March, so further decline is expected,” the NSIDC researchers said. “Much of the Antarctic coast is ice free. Earlier studies have linked low sea ice cover with wave-induced stresses on the floating ice shelves that hem the continent, leading to break up of weaker areas.”
The German scientists said the “intense melting” could be due to unusually high air temperatures to the west and east of the Antarctic peninsula, which were about 1.5C above the long-term average. Furthermore, there have been strong westerly winds, which increase sea ice retreat. The result is “intensified melting of ice shelves, an essential aspect of future global sea-level rise”, the researchers said.
Historical records also show dramatic changes in Antarctica, they said. The Belgian research vessel Belgica was trapped in massive pack ice for more than a year in the Antarctic summer 125 years ago, in exactly the same region where the Polarstern vessel is now sailing in completely ice-free waters.
Prof Carlos Moffat, at the University of Delaware, US, and recently returned from a research cruise in the Southern Ocean, told Inside Climate News: “The extraordinary change we’ve seen this year is dramatic. Even as somebody who’s been looking at these changing systems for a few decades, I was taken aback by what I saw.”
Antarctic sea ice level now lowest on record.
There is now less sea-ice surrounding the Antarctic continent than at any
time since we began using satellites to measure it in the late 1970s. It is
the southern hemisphere summer, when you’d expect less sea-ice, but this
year is exceptional, according to the National Snow and Ice Data Center.
Winds and warmer air and water reduced coverage to just 1.91 million square
km (737,000 sq miles) on 13 February. What is more, the melt still has some
way to go this summer.
BBC 17th Feb 2023
Antarctic “doomsday glacier” melting at faster rate than in past 5,500 years
Two Antarctic glaciers are now losing ice at a faster rate than any time
over the past 5,500 years, with “potentially disastrous” implications for
sea level rise, new research has found. The Thwaites Glacier, known as the
“Doomsday glacier”, due to the grave risk its melting poses to the world,
is around the size of Great Britain, and its neighbour, the Pine Island
Glacier is only slightly smaller. The two glaciers form part of the Western
Antarctic Ice Sheet, which is being impacted by warming temperatures due to
the climate crisis, and are already contributing to global sea level rise.
Independent 16th June 2022
https://www.independent.co.uk/climate-change/news/antarctica-doomsday-glacier-ice-melt-b2102698.html
Future of Antarctica’s Larsen C ice-shelf will have consequences for sea level rise world-wide
| Scientists know the surface of the Larsen C ice shelf in Antarctica is melting, making it vulnerable to collapse. For the first time, we can rank the most important causes of melting over the recent past. In a new two-part paper in Journal of Geophysical Research: Atmospheres, we show how the amount of energy reaching the ice from the sun is the dominant factor, followed by warm winds, clouds and weather patterns. These drivers of melting can interact and overlap to reinforce or counteract each other, so it is a complex picture. Understanding what is causing melting over Larsen C is vital as it will help predict the future of the ice shelf, which will have knock-on consequences for sea levels worldwide. In 2002, Larsen C’s neighbouring ice shelf, Larsen B, experienced melting so severe that it eventually caused the shelf to collapse completely. Larsen C restrains glaciers that contain enough ice to raise global sea levels by around 22mm. Carbon Brief 14th April 2022 https://www.carbonbrief.org/guest-post-ranking-the-reasons-why-the-larsen-c-ice-shelf-is-melting |
Hotter Antarctic summers posing increasing threat to stability of world’s largest ice sheet
Hotter Antarctic summers posing increasing threat to stability of
world’s largest ice sheet, satellite observations show. The East
Antarctic ice sheet is the biggest land-based piece of frozen water on the
planet. It holds about 80 per cent of all ice in the world, stretching up
to 4,800 metres in thickness in some places, and containing enough water to
raise global sea levels by 52 metres. Humans are generally keen for it to
stay in place. But new research shows that warmer summers due to the
worsening climate crisis are seriously threatening the floating ice shelves
which fringe the ice sheet, helping hold it in place.
Independent 31st March 2022
https://www.independent.co.uk/climate-change/news/antarctic-heat-ice-sheet-threat-b2048301.html
Scientists caught off guard by massive ice shelf collapse in ‘coldest, driest’ part of Antarctica
Scientists caught off guard by massive ice shelf collapse in ‘coldest, driest’ part of Antarctica
A huge ice shelf has collapsed in Antarctica, coinciding with a period of intense and unseasonal heat which may have been “the straw that broke the camel’s back”.
Antarctic heat – a horrifying reminder of the future with global heating
“Shocking,” said the Met Office head; “bonkers,” according to an Antarctic researcher. The heat at both ends of the planet this week has scientists straining for adjectives. 40°C above normal in Antarctica,
30°C hotter than usual in the Arctic.
With temperatures so much above anything on record, scientists had to confirm that, no, it isn’t a typo:
this is really happening.
Last week, the Conger ice shelf, which sits off the East Antarctic coast and is around 1,200 square kilometers across, collapsed completely. Ice sheets hold back the flow of ice into the sea.
“If they collapse, then ice flow from inland accelerates and leads to sea level rise,” said Andrew Mackintosh, a scientist at Monash University in Australia.
A natural reaction to such news is to fear the ice sheets might collapse entirely. If the West Antarctic ice sheet collapsed into theocean, global sea-levels could rise several metres – much faster and
further than expected – swamping coastal cities. That is not likely to happen soon, but the polar heat is a horrifying reminder of the stakes involved.
Independent 25th March 2022
https://www.independent.co.uk/climate-change/opinion/higher-food-prices-climate-crisis-b2043988.html
Temperatures in eastern Antarctica are 70 degrees warmer than usual
Temperatures in eastern Antarctica are 70 degrees warmer than usual https://thehill.com/policy/energy-environment/e2-wire/598842-temperatures-in-eastern-antarctica-are-70-degrees-warmer BY SARAKSHI RAI – 03/18/22
Eastern Antarctica on Friday recorded temperatures that are 70 degrees higher than normal for this time of the year, The Washington Post reported.
Temperatures in the eastern part of the continent have soared 50 to 90 degrees above normal, raising concern from the scientific community.
The Post reported that instead of temperatures being between minus 50 and minus 60 degrees Fahrenheit, they’ve been closer to zero or 10 degrees Fahrenheit, which is considered to be a massive heat wave by Antarctic standards.
BY SARAKSHI RAI – 03/18/22
Temperatures in eastern Antarctica are 70 degrees warmer than usual
BY SARAKSHI RAI – 03/18/22
© istock
Eastern Antarctica on Friday recorded temperatures that are 70 degrees higher than normal for this time of the year, The Washington Post reported.
Temperatures in the eastern part of the continent have soared 50 to 90 degrees above normal, raising concern from the scientific community.
The Post reported that instead of temperatures being between minus 50 and minus 60 degrees Fahrenheit, they’ve been closer to zero or 10 degrees Fahrenheit, which is considered to be a massive heat wave by Antarctic standards.
“In about 65 record years in Vostok, between March and October, values above -30°C were never observed,” climate journalist Stefano Di Battista told the news outlet in an email.
A researcher studying polar meteorology at the Université Grenoble Alpes Dr. Jonathan Wille also tweeted that this heatwave was “never supposed to happen.”
March marks the beginning of autumn in Antarctica, when temperatures usually tend to fall, The Post noted.
Willie tweeted that the warmer than usual conditions over Antarctica were caused by an extreme weather system.
“[T]his is not something we’ve seen before,” he said. “This moisture is the reason why the temperatures have gotten just so high,” he told The Post.
World’s largest iceberg melted – now one trillion tonnes of ice – gone
The monster iceberg A68 was dumping more than 1.5 billion tonnes of fresh water into the ocean every single day at the height of its melting. To put that in context, it’s about 150 times the amount of water used daily by all UK citizens.
A68 was, for a short period, the world’s biggest iceberg. It covered an area of nearly 6,000 sq km (2,300 sq miles) when it broke free from Antarctica in 2017. But by early 2021, it had vanished. One trilliontonnes of ice, gone.
BBC 20th Jan 2022
Fieldwork in the High Arctic found cataclysmic impact of climate change happening 70 years ahead of what the scientific models expected.
During the month of December 2021 two warnings of impending sea level rise were issued by highly respected groups of climate scientists. These are professional scientists who do not deal in hyperbole. Rather, they are archetypical conservative serious-minded scientists who follow the facts. The most recent warning on December 30th is of deteriorating conditions at the Arctic and Greenland. The second warning is the threatening collapse in Antarctica of one of the largest glaciers in the world. As these event unfortunately coincide so close together, one at the top of the world, the other at the bottom, should coastal cities plan to build sea walls? An article by M. Farquharson, et al in Geophysical Research Letters d/d June10, 2019 stated: “Observed maximum thaw depths at our sites are already exceeding those projected to occur by 2090.” In other words, fieldwork in the High Arctic found cataclysmic impact of climate change happening 70 years ahead of what the scientific models expected. Counterpunch 7th Jan 2022 https://www.counterpunch.org/2022/01/07/when-to-build-sea-walls/ |
Enormous Antarctic glacier becoming unstable
Boaty McBoatface craft to explore further beneath ‘Doomsday glacier’ than ever before
Glacier the size of the UK contains enough water to raise global sea levels by 65cm
Harry Cockburn, Environment Correspondent,
Antarctica’s enormous Thwaites glacier, AKA the “Doomsday glacier”, is the size of Britain, but is becoming increasingly unstable and poses a major risk to millions of people living on coastlines around the world.
Thwaites contains enough water to directly raise sea levels by 65cm if it collapses, but there are fears it could also spark a chain reaction leading to
even greater sea level rises of several metres. Now, a new research mission has been launched using a fleet of underwater robots, to further investigate the melting ice sheet which is – for now – holding the
glacier back.
Independent 6th Jan 2022
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See here the final program of the 12th International #Uranium Film Festival #Rio de Janeiro, May 18 – 28, 2023, Modern Art Museum (MAM Rio) #Cinematheque. uraniumfilmfestival.org/en/rio-2023-pr…
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