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.
South Pole warming at triple the global average
‘Nowhere to hide’: South Pole warms up with climate change a factor, https://www.smh.com.au/environment/climate-change/nowhere-to-hide-south-pole-warms-up-with-climate-change-a-factor-20200629-p55797.html, by Peter Hannam, June 30, 2020 The South Pole, the most remote part of the planet, has been warming at triple the global average, as natural variability joins with climate change to produce an abrupt shift in temperature trends.The findings, published Tuesday in the Nature Climate Change journal, show surface temperatures at the South Pole were stable in the first couple of decades of instrument records into the 1980s.
A record-breaking cold for a spell then made way for even warmer temperature anomalies from the early 2000s. For the 1989-2018 period, the mercury rose an average of 0.6 degrees per decade, or three times the global warming rate, the researchers found.
The report on the flipping of temperature trends at the most southerly point comes as abnormal warmth continues to bake the planet’s other polar extreme. The Russian town of Verkhoyansk last week reported 38 degrees, the warmest reading ever recorded within the Arctic Circle.
For Antarctica, the recent accelerated warming is estimated to be about two-thirds the result of natural variability with the role of rising greenhouse gases contributing about one-third, said Kyle Clem, a post-doctoral research fellow at New Zealand’s Victoria University.
The rapid warming “lies within the upper bounds of natural variability”, Dr Clem said. “It’s extremely rare and it appears very likely that humans played a role.”
The research shows “there’s no place on earth that’s immune to global warming”, he said. “There’s nowhere to hide – not even up on the Antarctic Plateau.”
Sitting at 2835 metres above sea level – or 600 metres higher than Mt Kosciuszko – on a rocky continent, the South Pole is exposed to different weather processes than its polar opposite. By contrast, the North Pole rests on shifting sea ice with the seabed more than four kilometres below.
Dr Clem, along with other researchers from the US and the UK, found changing circulation patterns in the Pacific and Southern Ocean determine which parts of Antarctica warm or cool.
For instance, the western tropical Pacific has periods when is warmer or cooler than usual.
The warmer period – known as the negative phase of the so-called Interdecadal Pacific Oscillation – set in about 2000. During this phase, there is more storm activity in the tropics which in turn spawns more high- and low-pressure systems that send heat far into the high latitudes.
The circumpolar westerly winds, which have been strengthening and contracting polewards under climate change – also play a role in amplifying the transfer of warmth into Antarctica.
When those two patterns align, as they have in recent decades, the South Pole warms but some parts, such as western Antarctica warm at a slow pace or even cool, as the frigid air shifts around.
Michael Mann, Director of the Earth System Science Centre at the University of Pennsylvania, said the study provided “a very detailed and useful analysis” of the forces at play in the far south.
If anything, though, the researchers’ use of model simulations to reach conclusions about regional trends probably understates the role of human-caused climate change.
“In short, what the authors attribute to natural internal cycles might just be a shift in atmospheric circulation that is actually due to human-caused climate change but isn’t accurately captured in the average over models,” Professor Mann said, in an email that included those italics.
The recent polar extremes – including eastern Siberian temperatures above 40 degrees – were important because “what happens in the poles doesn’t stay in the poles”, the prominent climate scientist said.
Changes at the South Pole itself were not as critical as the warming of the Southern Ocean, which is leading to the collapse of the West Antarctic ice shelves and the destabilisation of the interior ice sheet.
“This was not well predicted by climate models, meaning we are further along when it comes to the destabilisation of ice sheets and the commitment to rising sea levels than we expected to be at this point,” Professor Mann said.
Antarctic krill threatened by warming waters – climate change’s danger to the marine ecosystem
Climate change threatens Antarctic krill and the sea life that depends on it The Conversation, Devi Veytia, PhD student , University of Tasmania, Stuart Corney, Senior lecturer, University of Tasmania, 19 May 20,
The Southern Ocean circling Antarctica is one of Earth’s richest marine ecosystems. Its food webs support an abundance of life, from tiny micro-organisms to seals, penguins and several species of whales. But climate change is set to disrupt this delicate balance.
Antarctic krill – finger-sized, swarming crustaceans – might be small but they underpin the Southern Ocean’s food web. Our research published today suggests climate change will cause the ocean habitat supporting krill growth to move south. The habitat will also deteriorate in summer and autumn.
The ramifications will reverberate up the food chain, with implications for other Antarctic animals. This includes humpback whales that feed on krill at the end of their annual migration to the Southern Ocean.
What we found
Antarctic krill are one of the most abundant animal species in the world. About 500 million tonnes of Antarctic krill are estimated to exist in the Southern Ocean.
Antarctic krill play a critical role in the ocean’s food webs. But their survival depends on a delicate balance of food and temperature. Scientists are concerned at how climate change may affect their population and the broader marine ecosystem.
We wanted to project how climate change will affect the Southern Ocean’s krill “growth habitat” – essentially, ocean areas where krill can thrive in high numbers.
Krill growth depends largely on ocean temperature and the abundance of its main food source, phytoplankton (microscopic single-celled plants)………
Krill growth habitat shifted south as suitable ocean temperatures contracted towards the poles. Combined with changes in phytoplankton distribution, growth habitat improved in spring but deteriorated in summer and autumn.
This early end to the growth season could have profound consequences for krill populations. The krill life cycle is synchronised with the Southern Ocean’s dramatic seasonal cycles. Typically this allows krill to both maximise growth and reproduction and store reserves to survive the winter.
A shift in habitat timing could create a mismatch between these two cycles.
For example, female krill need access to plentiful food during the summer in order to spawn. Since larger females produce exponentially more eggs, a decline in summer growth habitat could result in smaller females and far less spawning success.
Why this matters
Krill’s significant role in the food chain means the impacts of these changes may play out through the entire ecosystem.
If krill shift south to follow their retreating habitat, less food would be available for predators on sub-Antarctic islands such as Antarctic fur seals, penguins and albatrosses for whom krill forms a significant portion of the diet.
In the past, years of low krill densities has coincided with declines in reproductive success for these species…….. https://theconversation.com/climate-change-threatens-antarctic-krill-and-the-sea-life-that-depends-on-it-138436
Petersberg Climate Dialogue to be held virtually this year
Sustainable Recovery**
Livestream recording of “Financing Climate Ambition in the context of
COVID-19”. A sustained green, resilient recovery from COVID-19 requires
significant investments to scale and achieve economy-wide transformation,
particularly in developing and emerging markets. Delivering this
sustainable recovery and creating new opportunities for growth will involve
accelerating the transition towards a low-carbon, resilient future that is
already underway.
Since its inception in 2010, the Petersberg Climate
Dialogue has provided a forum for high-level political discussions,
focusing both on the international climate negotiations and on advancing
climate action on the ground.
Dialogue has provided a forum for high-level political discussions,
focusing both on the international climate negotiations and on advancing
climate action on the ground.
This year, the Petersberg Climate Dialogue
will be held virtually for the first time, and will focus on climate
ambition in the context of a green, resilient recovery. See, in particular
Mark Carmey from 41.43 He asks “what can we do to drice climate finance
in support of the transition to a net zero economy?” A related question
is what will be the economics of a post-Covid world? The new economy will
require a massive reallocation of capital. It provides an opportunity to
require companies and sectors to have net zero transition plans. The aim of
his work on Cop-26 is to ensure that every financial decision takes climate
into account. 120 countries have committed to net zero. That means every
company, every sector, every pension fund in those countries should have a
net zero plan which it has disclosed. When countries are designing their
recovery strategies they would do well to use this new financial framework
that is centred around the transition to net zero because that will amplify
the effectiveness. Once the war against Covid in won our ambition should be
to build a planet fit for our grandchildren.
will be held virtually for the first time, and will focus on climate
ambition in the context of a green, resilient recovery. See, in particular
Mark Carmey from 41.43 He asks “what can we do to drice climate finance
in support of the transition to a net zero economy?” A related question
is what will be the economics of a post-Covid world? The new economy will
require a massive reallocation of capital. It provides an opportunity to
require companies and sectors to have net zero transition plans. The aim of
his work on Cop-26 is to ensure that every financial decision takes climate
into account. 120 countries have committed to net zero. That means every
company, every sector, every pension fund in those countries should have a
net zero plan which it has disclosed. When countries are designing their
recovery strategies they would do well to use this new financial framework
that is centred around the transition to net zero because that will amplify
the effectiveness. Once the war against Covid in won our ambition should be
to build a planet fit for our grandchildren.
Climate Policy Initiative 29th April 2020
https://www.youtube.com/watch?v=8sLyUMokSvI
Top regulator who steered banks’ revival after last crash has a new crisis
mission: ‘My green energy plan to spark the economy back to life’. With the
oil price at record lows, Lord Turner concedes that fossil fuels ‘are
suddenly going to look cheap’ as travel resumes – potentially making a
switch to cleaner energy less attractive. But he is adamant that investment
in green fuel would create jobs and give Britain’s post-coronavirus economy
a much-needed boost. For instance, a jobs cull in North Sea oil could be
offset by transferring workers with marine engineering skills to building
bases for offshore windfarms, he says. ‘North-west Europe is blessed with
huge amounts of offshore wind potential, and both the UK and the rest of
Europe should be planning for massive offshore wind developments in the
North Sea that can give us green electricity at a low price,’ he says.
‘It’s a huge strategic opportunity.’ When pressed on whether the Government
should bail out struggling companies, rather than letting some firms fail,
it’s the first time his smooth theorising is rattled. ‘I’m not getting into
the specifics of individual companies,’ he says testily. ‘But any company
that receives a bailout should have green targets attached.’
Daily Mail 2nd May 2020
Global warming influence on extreme weather events has been frequently underestimated
Global warming influence on extreme weather events has been frequently underestimated, Science Daily, March 18, 2020
- Source:
- Stanford University
- Summary:
- Analysis shows global warming is intensifying the occurrence of unprecedented hot spells and downpours faster than predicted by historical trends.
-
A new Stanford study reveals that a common scientific approach of predicting the likelihood of future extreme weather events by analyzing how frequently they occurred in the past can lead to significant underestimates — with potentially significant consequences for people’s lives.
Stanford climate scientist Noah Diffenbaugh found that predictions that relied only on historical observations underestimated by about half the actual number of extremely hot days in Europe and East Asia, and the number of extremely wet days in the U.S., Europe and East Asia.
The paper, published March 18 in Science Advances, illustrates how even small increases in global warming can cause large upticks in the probability of extreme weather events, particularly heat waves and heavy rainfall. The new results analyzing climate change connections to unprecedented weather events could help to make global risk management more effective.
- We are seeing year after year how the rising incidence of extreme events is causing significant impacts on people and ecosystems,” Diffenbaugh said. “One of the main challenges in becoming more resilient to these extremes is accurately predicting how the global warming that’s already happened has changed the odds of events that fall outside of our historical experience.”
A changing world……. https://www.sciencedaily.com/releases/2020/03/200318143722.htm
Polar ice melting at an accelerating rate
Polar ice caps melting six times faster than in 1990s https://www.theguardian.com/environment/2020/mar/11/polar-ice-caps-melting-six-times-faster-than-in-1990s
Losses of ice from Greenland and Antarctica are tracking the worst-case climate scenario, scientists warn Damian Carrington Environment editor @dpcarrington,Thu 12 Mar 2020 The polar ice caps are melting six times faster than in the 1990s, according to the most complete analysis to date.
The ice loss from Greenland and Antarctica is tracking the worst-case climate warming scenario set out by the Intergovernmental Panel on Climate Change (IPCC), scientists say. Without rapid cuts to carbon emissions the analysis indicates there could be a rise in sea levels that would leave 400 million people exposed to coastal flooding each year by the end of the century.
Rising sea levels are the one of the most damaging long-term impacts of the climate crisis, and the contribution of Greenland and Antarctica is accelerating. The new analysis updates and combines recent studies of the ice masses and predicts that 2019 will prove to have been a record-breaking year when the most recent data is processed.
The previous peak year for Greenland and Antarctic ice melting was 2010, after a natural climate cycle led to a run of very hot summers. But the Arctic heatwave of 2019 means it is nearly certain that more ice was lost last year.
The average annual loss of ice from Greenland and Antarctica in the 2010s was 475bn tonnes – six times greater than the 81bn tonnes a year lost in the 1990s. In total the two ice caps lost 6.4tn tonnes of ice from 1992 to 2017, with melting in Greenland responsible for 60% of that figure.
The IPCC’s most recent mid-range prediction for global sea level rise in 2100 is 53cm. But the new analysis suggests that if current trends continue the oceans will rise by an additional 17cm.
“Every centimetre of sea level rise leads to coastal flooding and coastal erosion, disrupting people’s lives around the planet,” said Prof Andrew Shepherd, of the University of Leeds. He said the extra 17cm would mean the number of exposed to coastal flooding each year rising from 360 million to 400 million. “These are not unlikely events with small impacts,” he said. “They are already under way and will be devastating for coastal communities.”
Erik Ivins, of Nasa’s Jet Propulsion Laboratory, in California, who led the assessment with Shepherd, said the lost ice was a clear sign of global heating. “The satellite measurements provide prima facie, rather irrefutable, evidence,” he said.
Almost all the ice loss from Antarctica and half of that from Greenland arose from warming oceans melting the glaciers that flow from the ice caps. This causes glacial flow to speed up, dumping more icebergs into the ocean. The remainder of Greenland’s ice losses are caused by hotter air temperatures that melt the surface of the ice sheet.
The combined analysis was carried out by a team of 89 scientists from 50 international organisations, who combined the findings of 26 ice surveys. It included data from 11 satellite missions that tracked the ice sheets’ changing volume, speed of flow and mass.
About a third of the total sea level rise now comes from Greenland and Antarctic ice loss. Just under half comes from the thermal expansion of warming ocean water and a fifth from other smaller glaciers. But the latter sources are not accelerating, unlike in Greenland and Antarctica.
Shepherd said the ice caps had been slow to respond to human-caused global heating. Greenland and especially Antarctica were quite stable at the start of the 1990s despite decades of a warming climate.
Shepherd said it took about 30 years for the ice caps to react. Now that they had a further 30 years of melting was inevitable, even if emissions were halted today. Nonetheless, he said, urgent carbon emissions cuts were vital. “We can offset some of that [sea level rise] if we stop heating the planet.”
The IPCC is in the process of producing a new global climate report and its lead author, Prof Guðfinna Aðalgeirsdóttir, of the University of Iceland, said: “The reconciled estimate of Greenland and Antarctic ice loss is timely.”
She said she also saw increased losses from Iceland’s ice caps last year. “Summer 2019 was very warm in this region.”
Nuclear testing left a signature of radioactive carbon all around the world
When Linus Pauling accepted the 1962 Nobel Peace Prize for his campaigning against hydrogen bombs, he said that carbon 14 “deserves our special concern” because it “shows the extent to which the earth is being changed by the tests of nuclear weapons.”
If people’s teeth have a very low level of radiocarbon, it means that they were born well before Castle Bravo. [thermonuclear atom bomb test] People born in the early 1960s have high levels of radiocarbon in their molars, which develop early, and lower levels in their wisdom teeth, which grow years later. By matching each tooth in a jaw to the bomb curve, forensic scientists can estimate the age of a skeleton to within one or two years.
Even after childhood, bomb radiocarbon chronicles the history of our body.
Your Inner H-Bomb Nuclear testing left a signature of radioactive carbon all around the world—in trees and sharks, in oceans and human bodies. Even as that signal disappears, it’s revealing new secrets to scientists. The Atlantic, Story by Carl Zimmer, 2 Mar 20, “…… Among the isotopes created by a thermonuclear blast is a rare, radioactive version of carbon, called carbon 14. Castle Bravo and the hydrogen-bomb tests that followed it created vast amounts of carbon 14, which have endured ever since. A little of this carbon 14 made its way into Clark’s body, into his blood, his fat, his gut, and his muscles. Clark carried a signature of the nuclear weapons he tested to his grave.
I can state this with confidence, even though I did not carry out an autopsy on Clark. I know this because the carbon 14 produced by hydrogen bombs spread over the entire world. It worked itself into the atmosphere, the oceans, and practically every living thing. As it spread, it exposed secrets. It can reveal when we were born. It tracks hidden changes to our hearts and brains. It lights up the cryptic channels that join the entire biosphere into a single network of chemical flux. This man-made burst of carbon 14 has been such a revelation that scientists refer to it as “the bomb spike.” Only now is the bomb spike close to disappearing, but as it vanishes, scientists have found a new use for it: to track global warming, the next self-inflicted threat to our survival. ……. Continue reading
Antarctic ice walls protect the climate
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Antarctic ice walls protect the climate, EurekAlert 27 Feb, UNIVERSITY OF GOTHENBURG Inland Antarctic ice contains volumes of water that can raise global sea levels by several metres. A new study published in the journal Nature shows that glacier ice walls are vital for the climate, as they prevent rising ocean temperatures and melting glacier ice.The ocean can store much more heat than the atmosphere. The deep sea around Antarctica stores thermal energy that is the equivalent of heating the air above the continent by 400 degrees. Now, a Swedish-led international research group has explored the physics behind the ocean currents close to the floating glaciers that surround the Antarctic coast. “Current measurements indicate an increase in melting, particularly near the coast in some parts of Antarctica and Greenland. These increases can likely be linked to the warm, salty ocean currents that circulate on the continental shelf, melting the ice from below,” says Anna Wåhlin, lead author of the study and professor of oceanography at the University of Gothenburg. “What we found here is a crucial feedback process: the ice shelves are their own best protection against warm water intrusions. If the ice thins, more oceanic heat comes in and melts the ice shelf, which becomes even thinner etc. It is worrying, as the ice shelves are already thinning because of global air and ocean warming”, says Céline Heuzé, climate researcher at the Department of Earth Sciences of Gothenburg University. The stability of ice is a mystery Inland Antarctic ice gradually moves towards the ocean. Despite the ice being so important, its stability remains a mystery – as does the answer to what could make it melt faster. Since the glaciers are difficult to access, researchers have been unable to find out much information about the active processes. More knowledge has now been obtained from studying the measurement data collected from instruments that Anna Wåhlin and her researcher colleagues placed in the ocean around the Getz glacier in West Antarctica. The ice’s edge blocks warm seawater……https://www.eurekalert.org/pub_releases/2020-02/uog-aiw022720.php |
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Scientists warn on the seriousness of the collapse of many insect species
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Experts call for solutions to be enforced immediately to halt global population collapses, Guardian Damian Carrington Environment editor @dpcarrington, Thu 20 Feb 2020 .The “fates of humans and insects are intertwined”, scientists have said, with the huge declines reported in some places only the “tip of the iceberg”.The warning has been issued by 25 experts from around the world, who acknowledge that little is known about most of the estimated 5.5 million insect species. However, enough was understood to warrant immediate action, they said, because waiting for better data would risk irreversible damage. The researchers said solutions were available and must be implemented immediately. These range from bigger nature reserves and a crackdown on harmful pesticides to individual action such as not mowing the lawn and leaving dead wood in gardens. They also said invertebrates must no longer be neglected by conservation efforts, which tend to focus on mammals and birds…….https://www.theguardian.com/environment/2020/feb/20/fates-humans-insects-intertwined-scientists-population-collapse |
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All wars are serious, but this climate war could have the direst consequences
THE ONE WAR THAT THE HUMAN SPECIES CAN’T LOSE The New Yorker, By Robin Wright, 20 Feb 2020 “……… For almost a half century, I’ve covered wars, revolutions and uprisings on four continents, many for years on end. I’ve always been an outside observer watching as others killed each other. I lamented the loss of human life—and the warring parties’ self-destructive practices—from an emotional distance. In Antarctica, I saw war through a different prism. And I was the enemy. “ “Humans will be but a blip in the span of Earth’s history,” Wayne Ranney, a naturalist and geologist on the expedition, told me. “The only question is how long the blip will be.”
Last week, the temperature in Antarctica hit almost seventy degrees—the hottest in recorded history. It wasn’t a one-day fluke. Famed for its snowscapes, the Earth’s coldest, wildest, windiest, highest, and most mysterious continent has been experiencing a heat wave. A few days earlier, an Antarctic weather station recorded temperatures in the mid-sixties. It was colder in Washington, D.C., where I live. Images of northern Antarctica captured vast swaths of barren brown terrain devoid of ice and with only small puddle-like patches of snow.
The problem is not whether a new record was set, “it’s the longer-term trend that makes those records more likely to happen more often,” John Nielsen-Gammon, the director of the Texas Center for Climate Studies at Texas A. & M. University, told me this week……
The iceberg that I watched break off from Antarctica was part of a process called calving. It’s normal and a necessary step in nature’s cycle, except that it’s now happening a lot faster and in larger chunks—with existential stakes. The ice in Antarctica is now melting six times faster than it did forty years ago, Eric Rignot, an Earth scientist at the University of California, Irvine, and a co-author of a major study of the continent’s ice health, told me.
This month, an iceberg measuring more than a hundred square miles—the size of the Mediterranean island of Malta, or twice the size of Washington, D.C.—broke off the Pine Island Glacier (lovingly known as pig, for short) in West Antarctica. It then broke up into smaller “pig-lets,” according to the European Space Agency, which tracked them by satellite. The largest piglet was almost forty square miles.
The frozen continent is divided into West Antarctica and East Antarctica. (The South Pole is in East Antarctica.) Most of the melting and much of the big calving has happened in the West and along its eight hundred-mile peninsula. But, in September, an iceberg measuring more than six hundred square miles—or twenty-seven times the size of Manhattan—calved off the Amery Ice Shelf, in East Antarctica. Calving has accelerated in startling style. Two other huge soon-to-be bergs are being tracked as their crevices and cracks become visible from space. One is from pig in the West, the other is forming off the Brunt Ice Shelf in the East……….
“By 2035, the point of no return could be crossed,” Matthew Burrows, a former director at the National Intelligence Council, wrote in a report last year about global risks over the next fifteen years. That’s the point after which stopping the Earth’s temperature from rising by two degrees Celsius—or 3.6 degrees Fahrenheit—will be extremely difficult, if not impossible, in turn triggering “a dangerous medley of global disasters.”
And that, in turn, goes back to ice and its role in fostering human civilization. “What’s coming—or is happening—is the end of the earth’s stability,” Glendon told me. “In human terms, that means a return to migration, but in a population of not just a few million, but several billion.”
Before I went to Antarctica, I checked in with Donald Perovich, a geophysicist at Dartmouth who tracks sea ice. We got to talking about wars. “You can argue that in all wars, there are winners and losers. Afterward, societies go on. There’s an opportunity to recover and move forward. If you approach climate change as a war, there are some really severe consequences across the board,” he told me. “This,” he added, “is the one war we can’t lose.” https://www.newyorker.com/news/dispatch/antarcticas-ice-the-one-war-that-the-human-species-cant-lose?source=EDT_NYR_EDIT_NEWSLETTER_0_imagenewsletter_Daily_ZZ&utm_campaign=aud-dev&utm_source=nl&utm_brand=tny&utm_mailing=TNY_Daily_022020&utm_medium=email&bxid=5bea00ac3f92a404693b7a69&cndid=46508601&esrc=&mbid=&utm_term=TNY_Daily
Giant iceberg ‘calves’ from Antarctic ice shelf
Shrinking Antarctic ice shelf Pine Island Glacier sheds giant iceberg, ABC News, Digital Story Innovation Team By Mark Doman 14 Feb 20, In one of the fastest-changing areas of the Antarctic ice sheet, satellites have captured the formation of a giant, 300-square-kilometre iceberg.
Researchers monitoring satellite imagery of the Pine Island Glacier (PIG), in west Antarctica, first noticed two large rifts forming in the shelf in 2019.
Over the next few months, as the glacier moved out towards the Amundsen Sea, the rifts expanded, eventually leading to the splitting of the iceberg from the glacier on February 9.
Within a day, the iceberg had broken up into smaller pieces.
Only one of the pieces was large enough to be named (B-49) and tracked by the United States National Ice Centre.
It comes just days after a station on the Antarctic Peninsula logged its hottest day on record, registering a temperature of 18.3 degrees Celsius.
The peninsula, which juts out to the north-east of the Pine Island Glacier, is among the fastest-warming regions on the planet. Temperatures there have increased almost 3C over the last 50 years, according to the World Meteorological Organisation.
Last month, scientists also recorded unusually warm water beneath the Thwaites Glacier, a neighbour to Pine Island.
While the calving of icebergs from shelves such as the Pine Island Glacier is a natural process in the life of a giant glacier, the rate at which this glacier and others in the region have been disintegrating is a cause of concern for scientists.
Previously the ice shelf calved once a decade. By the early 2000s, it started calving once every five years. But since 2013, the glacier has calved five times, according to Stef Lhermitte, a remote sensing scientist from the Delft University of Technology in the Netherlands……. https://www.abc.net.au/news/2020-02-13/antarctic-ice-shelf-pine-island-glacier-sheds-giant-iceberg/11957770
Antarctic ice sheets could be at greater risk of melting than previously thought
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Radioactive chlorine from nuclear bomb tests still present in Antarctica
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Radioactive chlorine from nuclear bomb tests still present in Antarctica, Phys Org, by Abigail Eisenstadt, American Geophysical Union 16 Oct 19, Antarctica’s ice sheets are still releasing radioactive chlorine from marine nuclear weapons tests in the 1950s, a new study finds. This suggests regions in Antarctica store and vent the radioactive element differently than previously thought. The results also improve scientists’ ability to use chlorine to learn more about Earth’s atmosphere. Scientists commonly use the radioactive isotopes chlorine-36 and beryllium-10 to determine the ages of ice in ice cores, which are barrels of ice obtained by drilling into ice sheets. Chlorine-36 is a naturally occurring radioactive isotope, meaning it has a different atomic mass than regular chlorine. Some chlorine-36 forms naturally when argon gas reacts with cosmic rays in Earth’s atmosphere, but it can also be produced during nuclear explosions when neutrons react with chlorine in seawater. Nuclear weapons tests in the United States carried out in the Pacific Ocean during the 1950s and the 1960s caused reactions that generated high concentrations of isotopes like chlorine-36. The radioactive isotope reached the stratosphere, where it traveled around the globe. Some of the gas made it to Antarctica, where it was deposited on Antarctica’s ice and has remained ever since. Other isotopes produced by marine nuclear bomb testing have mostly returned to pre-bomb levels in recent years. Scientists expected chlorine-36 from the nuclear bomb tests to have also rebounded. But new research in AGU’s Journal of Geophysical Research: Atmospheres finds the Vostok region of Antarctica is continuing to release radioactive chlorine into the atmosphere. Since naturally produced chlorine-36 is stored permanently in layers of Antarctica’s snow, the results indicate the site surprisingly still has manmade chlorine produced by bomb tests in the 1950s and in the 1960s……… https://phys.org/news/2019-10-radioactive-chlorine-nuclear-antarctica.html |
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Surface melting causes Antarctic glaciers to slip faster towards the ocean
Direct link between surface melting and short bursts of glacier acceleration in Antarctica
- Date:
- September 20, 2019
- Source:
- University of Sheffield
- Summary:
- Study shows for the first time a direct link between surface melting and short bursts of glacier acceleration in Antarctica. During these events, Antarctic Peninsula glaciers move up to 100% faster than average. Scientists call for these findings to be accounted for in sea level rise predictions…….
https://www.sciencedaily.com/releases/2019/09/190920111355.htm
One million species at risk of extinction, UN report warns, and we are mostly to blame
ABC , By Lexi Metherell 6 May 19,
One million of the world’s species are now under threat of extinction, according to the biggest-ever review of the state of nature on Earth.
Key points:
- The report, which draws on 15,000 scientific and government sources, says human use of land and ea resources are mostly to blame
- The decline in nature is happening at rates that are unprecedented in human history, the UN report reveals
- More than 40 per cent of amphibian species, almost 33 per cent of reef-forming corals and more than a third of all marine mammals are threatened
The UN-backed report was three years in the making and was based on systematic reviews of 15,000 scientific and government sources.
Among a vast number of alarming findings is that the average population size of native species in most habitats on land has fallen by at least 20 per cent, mostly since 1900.
More than 40 per cent of amphibian species, almost 33 per cent of reef-forming corals and more than a third of all marine mammals are now under threat.
“We are eroding the very foundations of our economies, livelihoods, food security, health and quality of life worldwide,” said Sir Robert Watson, the chair of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), which put together the report.
The IPBES has 132 nation-members and is known as the equivalent of the Intergovernmental Panel on Climate Change (IPCC), but for biodiversity.
Human expansion and exploitation of habitats to blame
The report says that human use of the land and sea resources are mostly to blame, followed by direct exploitation of animals, climate change, pollution and invasive species.
More than a third of the world’s land surface and nearly 75 per cent of freshwater resources are now devoted to crop or livestock production, while urban areas have more than doubled since 1992.
Meanwhile, 300-400 million tonnes of heavy metals, solvents, toxic sludge and other waste is dumped into the world’s waters every year.
The decline in nature is happening at rates that are unprecedented in human history.
“It’s like reading a paper that says the natural world is in catastrophic decline and there is a chance that this catastrophe will take us all down with it,” said Tim Beshara, federal policy director of Wilderness Society.
Humanity is causing a slow-motion apocalypse of the natural world and that’s getting faster and faster as time goes on.”…………
Next year is a big year for global conservation. The signatories to the Convention on Biological Diversity, which is the global treaty meant to safeguard biodiversity, are scheduled to meet and sign a new post-2020 strategic plan.
Professor Watson said it’s an opportunity to reset the clock and design a global deal for nature and biodiversity.
“The sad thing is Australia has gone missing in these negotiations, they haven’t even turned up to the last major international negotiations around this matter, and as you are seeing in the federal election, biodiversity is just not even mentioned,” he said.
“That’s a shame because Australia is one of the few mega-biodiverse countries around the world — we have more species than just about every other country.” https://www.abc.net.au/news/2019-05-06/biggest-global-assessment-of-biodiversity-sounds-dire-warnings/11082940
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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