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Ice sheets melting, ocean currents, and the risk of climate tipping points

Ice sheets and ocean currents at risk of climate tipping points can
destabilise each other as the world heats up, leading to a domino effect
with severe consequences for humanity, according to a risk analysis.

Tipping points occur when global heating pushes temperatures beyond a
critical threshold, leading to accelerated and irreversible impacts. Some
large ice sheets in Antarctica are thought to already have passed their
tipping points, meaning large sea-level rises in coming centuries.

The new research examined the interactions between ice sheets in West Antarctica,
Greenland, the warm Atlantic Gulf Stream and the Amazon rainforest. The
scientists carried out 3m computer simulations and found domino effects in
a third of them, even when temperature rises were below 2C, the upper limit
of the Paris agreement.

Yhe study showed that the interactions between
these climate systems can lower the critical temperature thresholds at
which each tipping point is passed. It found that ice sheets are potential
starting points for tipping cascades, with the Atlantic currents acting as
a transmitter and eventually affecting the Amazon.

 Guardian 3rd June 2021

June 5, 2021 Posted by | ANTARCTICA, ARCTIC, climate change | Leave a comment

Ominous news; Antarctic ice is melting at an accelerating rate

Climate News Network 4th March 2021, Antarctic warming is accelerating: at least one of the southern  continent’s ice shelves has been melting faster than ever. The polar summer of 2019-20 set a new record for temperatures above freezing point over the George VI ice shelf off the Antarctic Peninsula.
The finding is ominous: the ice shelves form a natural buttress that slows the rate of glacier flow from the continental bedrock. The faster the glaciers flow into the sea, the higher the hazard of sea level rise. And a second study confirms that this is already happening in West Antarctica: researchers looked at 25 years of satellite observation of 14 glaciers in the Getz sector to find that meltwater is flowing into the Amundsen Sea ever faster.
Between 1994 and 2018, these glaciers lost 315 billion tonnes of ice, enough to raise global sea levels by almost 1mm. Melting rates in Antarctica have been a source of alarm for years. The latest studies confirm the picture of continuing melt.

March 6, 2021 Posted by | ANTARCTICA, climate change | Leave a comment

Vital need to protect Antarctic seas: groups aim for new protected areas

‘No other choice’: Groups push to protect vast swaths of Antarctic seas, Mongabay

  • A coalition of conservation groups is advocating for the establishment of three new marine protected areas (MPAs) in East Antarctica, the Antarctic Peninsula and the Weddell Sea, which would encompass 4 million square kilometers (1.5 million square miles) of the Southern Ocean, or 1% of the global ocean.
  • These proposals will be discussed at an upcoming meeting of the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR), which is due to take place online because of the pandemic.
  • Conservationists anticipate that China and Russia may not support these MPA proposals due to fishing interests in the region, although they are optimistic that the MPAs will eventually be approved.
‘……………… While Antarctica’s land mass is currently protected through the Antarctic Treaty (although this expires in 2048), vast swaths of its marine region are open to industrial fishing for species such as Antarctic krill (Euphausia superba) and Patagonian toothfish (Dissostichus eleginoides). Conservationists say these fishing activities are endangering the Southern Ocean’s delicate marine ecosystem that hosts more than 15,000 species, and a region that plays a vital role in regulating the world’s climate.

A coalition of conservation groups, including Pew, ASOC, SeaLegacy, Antarctica2020, Ocean Unite, and Only One, are working together to advocate for the formation of three marine protected areas (MPAs) in East Antarctica, the Antarctic Peninsula, and the Weddell Sea. Together, these areas would protect about 4 million square kilometers (1.5 million square miles), encompassing 1% of the world’s ocean. That’s two and a half times the size of Alaska, and nearly three times the size of Papahānaumokuākea Marine National Monument in Hawaiʻi, which is currently one of the world’s largest marine sanctuaries.

“If these three marine protected areas … [are] created at the same time, it would form the largest marine protection in the history of humanity,” Cristina Mittermeier, National Geographic wildlife photographer and co-founder of SeaLegacy, told Mongabay. “[It would be] a piece of good news that the planet needs.”

This is a matter of political will’

The body responsible for making decisions surrounding Antarctica’s marine region is the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR), an international commission with 25 member states and the European Union, as well as 10 acceding states. Originally established to manage krill fisheries in the Southern Ocean, the commission meets each year in Hobart, Australia, to negotiate total allowable catches for fisheries, and to discuss other matters related to Antarctica’s marine region, including the designation of MPAs.

Any decision requires a consensus among all members, and proposals can take a long time to be approved. For instance, it took more than five years for the commission to approve a proposal to turn a region of the Ross Sea into an MPA, according to Werner. But it finally went ahead in 2016: now 1.55 million km2 (nearly 600,000 mi2)of the Ross Sea is classified as an MPA, with 1.12 million km2 (432,000 mi2) of the region fully protected from commercial fishing.

“In CCAMLR, everything is possible,” said Werner, who acts as an official observer and scientific representative at the commission. “You can have a proposal blocked for years like the Ross Sea, and then one day [it happens].”…………

The way that Antarctica goes, so does the world’

One of the most important species living in the Southern Ocean is krill. These tiny, shrimp-like crustaceans are the foodstuff for many species, such as whales, seals, penguins, squids, fish and seabirds. Without krill, the pelagic food web would entirely collapse.

Krill is also heavily harvested for human consumption, mainly for fish meal and omega-3 dietary supplements.

The establishment of the three proposed MPAs — which would include no-take zones, but also areas that would allow regulated fishing — would help protect krill populations from overharvesting and enable fishing activities to continue in other areas, Cousteau said. According to one study, MPAs help increase fish mass………

But it’s not just fishing that’s a threat to krill — climate change is wreaking havoc on the species as high temperatures melt the ice it vitally depends upon. ……..

October 22, 2020 Posted by | ANTARCTICA, oceans | Leave a comment

Scientific women get together in plan for marine protected area for Antarctica Peninsula

All-female scientific coalition calls for marine protected area for Antarctica Peninsula Plus other ways to help penguins, whales, and seabirds, EurekAlert, UNIVERSITY OF SYDNEY, Research News  19 Oct 20, The Western Antarctic Peninsula is one of the fastest warming places on earth. It is also home to threatened humpback and minke whales, chinstrap, Adélie and gentoo penguin colonies, leopard seals, killer whales, seabirds like skuas and giant petrels, and krill – the bedrock of the Antarctic food chain.With sea ice covering ever-smaller areas and melting more rapidly due to climate change, many species’ habitats have decreased. The ecosystem’s delicate balance is consequently tilted, leaving species in danger of extinction.

Cumulative threats from a range of human activities including commercial fishing, research activities and tourism combined with climate change is exacerbating this imbalance, and a tipping point is fast approaching.

Dr Carolyn Hogg, from the University of Sydney School of Life and Environmental Sciences, was part of the largest ever all-female expedition to the Antarctic Peninsula, with the women in STEMM initiative, Homeward Bound, in late 2019. There, she witnessed the beauty and fragility of the area, and the negative impacts of climate change and human activity on native species, first-hand. As part of the Homeward Bound program she learnt about the science, conservation and governance of Antarctica.

In a new commentary piece published in Nature, Dr Hogg and her colleagues from the expedition outline these threats, and importantly, offer ways to counter them. More than 280 women in STEMM who have participated in the Homeward Bound initiative are co-signatories to the piece.

A global initiative, Homeward Bound ‘aims to elevate the voices of women in science, technology, engineering mathematics and medicine in leading for positive outcomes for our planet’.

Women are noticeably absent in Antarctica’s human history, which is steeped in tales of male heroism. Female scientists are still a minority in the region’s research stations.

“Now, more than ever, a broad range of perspectives is essential in global decision-making, if we are to mitigate the many threats our planet faces,” said Dr Hogg.

“Solutions include the ratification of a Marine Protected Area around the Peninsula, set to be discussed on 19 October, at a meeting of a group of governments that collectively manage the Southern Ocean’s resources,” said Dr Hogg. “The region is impacted by a number of threats, each potentially problematic in their own right, but cumulated together they will be catastrophic.”

Decreasing krill affects whole ecosystem

The Peninsula’s waters are home to 70 percent of Antarctic krill. In addition to climate change, these krill populations are threatened by commercial fishing. Last year marked the third largest krill catch on record. Nearly 400,000 tonnes of this animal were harvested, to be used for omega-3 dietary supplements and fishmeal.

“Even relatively small krill catches can be harmful if they occur in a particular region, at a sensitive time for the species that live there,” said Dr Cassandra Brooks, a co-author on the comment from the University of Colorado, Boulder. “For example, fishing when penguins are breeding lowers their food intake, and affects their subsequent breeding success. A Marine Protected Area will conserve and protect this unique ecosystem and its wildlife, and we need to implement it now.”

Climate change is fundamentally altering the Western Antarctic Peninsula:……

Three ways to protect the Peninsula

1. A Marine Protected Area (MPA) designation for the waters………

2. Protect land areas ………

3. Integrate conservation efforts…….


October 20, 2020 Posted by | 2 WORLD, ANTARCTICA, climate change, environment | Leave a comment

The United Nations weather agency on the impact of climate change on the cryosphere

Climate change: UN agency laments northern summer’s ‘deep wound’ to Earth’s ice cover, By Associated Press-Sep 1, 2020   The United Nations weather agency says this summer will go down for leaving a “deep wound” in the cryosphere — the planet’s frozen parts — amid a heat wave in the Arctic, shrinking sea ice and the collapse of a leading Canadian ice shelf.


The World Meteorological Organisation said today that temperatures in the Arctic are rising twice as fast as the global average, provoking what spokeswoman Clare Nullis called a “vicious circle.”
“The rapid decline of sea ice in turn contributes to more warming, and so the circle goes on and the consequences do not stay in the Arctic,” Ms Nullis said during a regular UN briefing in Geneva.
The weather agency said in a statement that many new temperature records have been set in recent months, including in the Russian town of Verkhoyansk. The town, located in Siberia above the Arctic Circle line, reached 38 degrees Celsius on June 20.
“What we saw in Siberia this year was exceptionally bad, was exceptionally severe,” Ms Nullis said.
She noted a heat wave across the Arctic, record-breaking wildfires in Siberia, nearly record-low sea ice extent, and the collapse of one of the last fully intact Canadian ice shelves.
“The summer of 2020 will leave a deep wound on the cryosphere,” the World Meteorological Organisation statement said, pointing to a “worrisome trend” of floods resulting from the outburst of glacier lakes that are becoming “an increased factor of high-risk in many parts of the world.”
In late July, an 81-square-kilometre section of Canada’s Milne ice shelf broke off, reducing the total area of the ice shelf by 43 per cent, the weather agency said.
The consequences include the loss of a rare ecosystem, possible acceleration of glaciers sliding into the ocean and contributing to sea level rise, and creation of new “drifting ice islands,” it said.
The WMO is preparing to release on September 9 a report on the impact of climate change on the cryosphere.

September 7, 2020 Posted by | ANTARCTICA, ARCTIC, climate change | Leave a comment

Antarctica – global heating and nuclear issues – polar theme for September 20

Antarctica is not in the news as much as the Arctic is,  But global heating is affecting Antarctica too, and Antarctica has its nuclear issues.

Antarctica has made headlines several times this year due to extremely warmer than usual temperatures. It has been steadily heating up for decades.  Antarctic ice shelves have lost nearly 4 trillion metric tons of ice since the mid-1990s, scientists say. Ocean water is melting them from the bottom up, causing them to lose mass faster than they can refreeze.  As ice shelves melt, they become thinner, weaker and more likely to break. When this happens, they can unleash streams of ice from the glaciers behind them, raising global sea levels. Antarctica is also losing ice from melting ice sheets, and chunks of ice falling from glaciers.

Less studied than the Arctic region, Antarctic is now being investigated by Australian researchers, using robots to gather data from difficult to reach underwater areas. Satellite monitoring confirms the shelves’ melting trend.

Nuclear issues.  From 6,000 nautical miles away, uranium mining in Australia is polluting the Antarctic.  After 1945 atomic bomb testing sent radioactive pollution to the South Pole, as well as to everywhere else on the planet.

USA  operated  a small nuclear power plant at Antarctica’s McMurdo Sound. It was known as “nukey poo” because of its frequent radioactive leaks. It had 438 malfunctions – nearly 56 a year – in its operational lifetime, including leaking water surrounding the reactor and hairline cracks in the reactor lining. The emissions of low level waste water where in direct contravention of the Antarctic Treaty, which bans military operations as well as radioactive waste in Antarctica. After the reactor was closed down, the US shipped 7700 cubic metres of radioactive contaminated rock and dirt to California.  Many USA naval workers there developed cancers.

Today, small nuclear reactors similar to this one, are being touted for remote areas in Australia and other countries. The history of this one in Antarctica, and 7 others elsewhere, was one of malfunctions, and closing down within a few years. This does not augur well for the small nuclear reactors being promoted today.

September 6, 2020 Posted by | ANTARCTICA, Christina's themes | 6 Comments

Sea level rise from melting ice sheets match worst-case climate warming scenarios.

Sea level rise from ice sheets track worst-case climate change scenario,   August 31, 2020

Source:  University of Leeds
Ice sheets in Greenland and Antarctica whose melting rates are rapidly increasing have raised the global sea level by 1.8cm since the 1990s, and are matching the Intergovernmental Panel on Climate Change’s worst-case climate warming scenarios.

Ice sheets in Greenland and Antarctica whose melting rates are rapidly increasing have raised the global sea level by 1.8cm since the 1990s, and are matching the Intergovernmental Panel on Climate Change’s worst-case climate warming scenarios.

According to a new study from the University of Leeds and the Danish Meteorological Institute, if these rates continue, the ice sheets are expected to raise sea levels by a further 17cm and expose an additional 16 million people to annual coastal flooding by the end of the century.

Since the ice sheets were first monitored by satellite in the 1990s, melting from Antarctica has pushed global sea levels up by 7.2mm, while Greenland has contributed 10.6mm. And the latest measurements show that the world’s oceans are now rising by 4mm each year.

“Although we anticipated the ice sheets would lose increasing amounts of ice in response to the warming of the oceans and atmosphere, the rate at which they are melting has accelerated faster than we could have imagined,” said Dr Tom Slater, lead author of the study and climate researcher at the Centre for Polar Observation and Modelling at the University of Leeds.

“The melting is overtaking the climate models we use to guide us, and we are in danger of being unprepared for the risks posed by sea level rise.”

The results are published today in a study in the journal Nature Climate Change. It compares the latest results from satellite surveys from the Ice Sheet Mass Balance Intercomparison Exercise (IMBIE) with calculations from climate models. The authors warn that the ice sheets are losing ice at a rate predicted by the worst-case climate warming scenarios in the last large IPCC report.Dr Anna Hogg, study co-author and climate researcher in the School of Earth and Environment at Leeds, said: “If ice sheet losses continue to track our worst-case climate warming scenarios we should expect an additional 17cm of sea level rise from the ice sheets alone. That’s enough to double the frequency of storm-surge flooding in many of the world’s largest coastal cities.”

So far, global sea levels have increased in the most part through a mechanism called thermal expansion, which means that volume of seawater expands as it gets warmer. But in the last five years, ice melt from the ice sheets and mountain glaciers has overtaken global warming as the main cause of rising sea levels.

Dr Ruth Mottram, study co-author and climate researcher at the Danish Meteorological Institute, said: “It is not only Antarctica and Greenland that are causing the water to rise. In recent years, thousands of smaller glaciers have begun to melt or disappear altogether, as we saw with the glacier Ok in Iceland, which was declared “dead” in 2014. This means that melting of ice has now taken over as the main contributor of sea level rise. ”

September 1, 2020 Posted by | ANTARCTICA, ARCTIC, climate change | Leave a comment

Ice melting at a surprisingly fast rate underneath Shirase Glacier Tongue in East Antarctica

East Antarctic melting hotspot identified
        August 24, 2020
Hokkaido University
Ice is melting at a surprisingly fast rate underneath Shirase Glacier Tongue in East Antarctica due to the continuing influx of warm seawater into the Lützow-Holm Bay.

Hokkaido University scientists have identified an atypical hotspot of sub-glacier melting in East Antarctica. Their findings, published in the journal Nature Communications, could further understandings and predictions of sea level rise caused by mass loss of ice sheets from the southernmost continent.

The 58th Japanese Antarctic Research Expedition had a very rare opportunity to conduct ship-based observations near the tip of East Antarctic Shirase Glacier when large areas of heavy sea ice broke up, giving them access to the frozen Lützow-Holm Bay into which the glacier protrudes.

“Our data suggests that the ice directly beneath the Shirase Glacier Tongue is melting at a rate of 7-16 meters per year,” says Assistant Professor Daisuke Hirano of Hokkaido University’s Institute of Low Temperature Science. “This is equal to or perhaps even surpasses the melting rate underneath the Totten Ice Shelf, which was thought to be experiencing the highest melting rate in East Antarctica, at a rate of 10-11 meters per year.”

The Antarctic ice sheet, most of which is in East Antarctica, is Earth’s largest freshwater reservoir. If it all melts, it could lead to a 60-meter rise in global sea levels. Current predictions estimate global sea levels will rise one meter by 2100 and more than 15 meters by 2500. Thus, it is very important for scientists to have a clear understanding of how Antarctic continental ice is melting, and to more accurately predict sea level fluctuations.

Most studies of ocean-ice interaction have been conducted on the ice shelves in West Antarctica. Ice shelves in East Antarctica have received much less attention, because it has been thought that the water cavities underneath most of them are cold, protecting them from melting.

During the research expedition, Daisuke Hirano and collaborators collected data on water temperature, salinity and oxygen levels from 31 points in the area between January and February 2017. They combined this information with data on the area’s currents and wind, ice radar measurements, and computer modelling to understand ocean circulation underneath the Shirase Glacier Tongue at the glacier’s inland base.

The scientists’ data suggests the melting is occurring as a result of deep, warm water flowing inwards towards the base of the Shirase Glacier Tongue. The warm water moves along a deep underwater ocean trough and then flows upwards along the tongue’s base, warming and melting the ice. The warm waters carrying the melted ice then flow outwards, mixing with the glacial meltwater.

The team found this melting occurs year-round, but is affected by easterly, alongshore winds that vary seasonally. When the winds diminish in the summer, the influx of the deep warm water increases, speeding up the melting rate.

“We plan to incorporate this and future data into our computer models, which will help us develop more accurate predictions of sea level fluctuations and climate change,” says Daisuke Hirano.

August 25, 2020 Posted by | ANTARCTICA, climate change, Reference | Leave a comment

Antarctic glacier melting at an alarming rate

Climate change: what Antarctica’s ‘doomsday glacier’ means for the planet, 

Thwaites Glacier is melting at an alarming rate, triggering fears over rising sea levels  Leslie Hook on the Antarctic Peninsula, Steven Bernard and Ian Bott in London , 13 Jul 20, 

 Even by the standards of Antarctica, there are few places as remote and hostile as Thwaites Glacier. More than 1,000 miles from the nearest research base, battered by storms that can last for weeks, with temperatures that hit -40C in winter, working on the glacier is sometimes compared to working on the moon.
 Dubbed the “doomsday” glacier, Thwaites, perhaps more than any other place in the world, holds crucial clues about the future of the planet. Only a handful of people had ever set foot on Thwaites before last year.
Now it is the focus of a major research project, led by British and American teams, as scientists race to understand how the glacier — which is the size of Britain and melting very quickly — is changing, and what that means for how much sea levels rise during our lifetimes.  ……
  understanding the Thwaites Glacier is not just academic — it is crucial for predicting how sea level rises will impact on cities, and how we should prepare for a radically different world. If Thwaites continues to deteriorate, then by the end of the century the glacier could be responsible for centimetres or tens of centimetres of sea level rise.
 “That doesn’t sound like much, but it is,” says David Vaughan, director of science at the British Antarctic Survey. “It is not about the sea coming up the beach slowly over 100 years — it is about one morning you wake up, and an area that has never been flooded in history is flooded.”
 Melting ice threatens US
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Antarctica holds around 90 per cent of the ice on the planet. It is equivalent to a continent the size of Europe, covered in a blanket of ice 2km thick. And as the planet heats up due to climate change, it doesn’t warm evenly everywhere: the polar regions warm much faster. It puts the icy continent of Antarctica and Greenland, the smaller Arctic region, right at the forefront of global warming. The South Pole has warmed at three times the global rate since 1989, according to a paper published last month.

As Antarctic ice melts and the glaciers slide toward the ocean, Thwaites has a central position, that governs how the other glaciers behave. Right now, Thwaites is like a stopper holding back a lot of the other glaciers in West Antarctica. But scientists are worried that could change. ……..

As Antarctic ice melts and the glaciers slide toward the ocean, Thwaites has a central position, that governs how the other glaciers behave. Right now, Thwaites is like a stopper holding back a lot of the other glaciers in West Antarctica. But scientists are worried that could change.  ……
  Right now climate modellers say sea levels will rise between 61cm and 110cm by the end of the century, assuming the world keeps emitting carbon dioxide at current levels. But if Thwaites collapses faster than expected, then the amount of sea level rise caused by Antarctica could be double what is in the models.   ……
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Impact of warming oceans The good news is that the Antarctic continent is not melting that much, yet. It currently contributes about 1mm per year to the sea level rise, a third of the annual global increase. But the pace of change at glaciers like Thwaites has accelerated at an alarming rate, even though it would take thousands of years for Antarctica itself to melt.

 As concentrations of carbon dioxide in the atmosphere increase to levels never before experienced by humans, researchers are trying to understand how the planet is changing.
Antarctica is central to that task. “Antarctica is by far the biggest risk,” in terms of extreme sea level rise, says Anders Levermann, a professor at the Potsdam Institute for Climate Impact Research, and the author of several papers on the Antarctic ice sheet.

July 14, 2020 Posted by | ANTARCTICA, climate change | Leave a comment

South Pole warming at triple the global average

‘Nowhere to hide’: South Pole warms up with climate change a factor,, 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.

June 30, 2020 Posted by | ANTARCTICA, climate change, Reference | Leave a comment

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……..

May 19, 2020 Posted by | ANTARCTICA, climate change, oceans | Leave a comment

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.
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.

Climate Policy Initiative 29th April 2020

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

May 3, 2020 Posted by | ANTARCTICA, climate change | Leave a comment

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

Stanford University
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…….

March 23, 2020 Posted by | ANTARCTICA, climate change | Leave a comment

Polar ice melting at an accelerating rate

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.”

March 14, 2020 Posted by | ANTARCTICA, ARCTIC, climate change, Reference | Leave a comment

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

March 3, 2020 Posted by | ANTARCTICA, environment, radiation, Reference, weapons and war | Leave a comment