Tag Archives: Antarctic

Climate heating may speed up to unexpected levels

When the ice thaws, ocean levels rise. And four new studies show climate heating can happen fast.

LONDON, 15 April, 2021 − If climate heating continues apace and the planet goes on warming, then up to a third of Antarctica’s ice shelf could tip into the sea.

And tip is the operative word, according to a separate study: at least one Antarctic glacier could be about to tip into rapid and irreversible retreat if temperatures go on rising.

And rise they could: evidence from the past in a third research programme confirms that at the end of the last Ice Age, Greenland’s temperature rose by somewhere between 5°C and 16°C in just decades, in line with a cascade of climate change events.

And ominously a fourth study of climate change 14,600 years ago confirmed that as the ice retreated, sea levels rose at 10 times the current rate, to 3.6 metres in just a century, and up to 18 metres in a 500-year sequence.

Each study is, on its own, an examination of the complexities of the planetary climate machine and the role of the polar ice sheets in climate change. But the message of the four together is a stark one: climate change is happening, could accelerate and could happen at unexpected speeds.

Unstable at 4°C

The Antarctic ice sheet floats on the sea: were it all to melt, sea levels globally would remain much the same. But the ice sheet plays an important role in stabilising the massive reserves of ice on the continental surface.

“Ice shelves are important buffers preventing glaciers on land from flowing freely into the ocean and contributing to sea level rise,” warned Ella Gilbert, a meteorologist at the University of Reading in the UK. “When they collapse, it’s like a giant cork being removed from a bottle, allowing unimaginable amounts of water from glaciers to pour into the sea.”

She and colleagues report in the journal Geophysical Research Letters that their detailed study of the vulnerable platforms of floating ice around the continent revealed that half a million square kilometres of shelf − 34% in total, including two-thirds of all the ice off the Antarctic Peninsula − would become unstable if global temperatures rose by 4°C, under the business-as-usual scenario in which nations went on burning ever-greater quantities of fossil fuel.

If however the world kept to the limit it agreed in Paris in 2015, that would halve the area at risk and perhaps avoid significant sea level rise. But already, just two Antarctic glaciers are responsible for around 10% of sea level rise at the current rate, and researchers have been warning for years that the Pine Island and Thwaites glaciers in West Antarctica could be at risk.

Now researchers in the UK report in the journal The Cryosphere that their computer simulation had identified a series of tipping points for the Pine Island flow.

“Ice shelves are important buffers preventing glaciers on land from contributing to sea level rise. When they collapse, it’s like a giant cork being removed from a bottle, allowing unimaginable amounts of water to pour into the sea”

The third of these, triggered by ocean temperatures that had warmed just 1.2°C, would lead to irretrievable retreat of the entire glacier. Hilmar Gudmundsson, a glaciologist at the UK’s Northumbria University and one of the authors, called the research a “major step forward” in the understanding of the dynamics of the region.

“But the findings of this study also concern me”, he said. “Should the glacier enter unstable irreversible retreat, the impact on sea level could be measured in metres, and as this study shows, once the retreat starts it might be impossible to halt it.”

Rapid polar melt is part of the pattern of climate history. Danish researchers report in Nature Communications that, on the evidence preserved in Greenland ice cores, they identified a series of 30 abrupt climate changes at the close of the Last Ice Age, affecting North Atlantic ocean currents, wind and rainfall patterns and the spread of sea ice: a set of physical processes that changed together, like a row of cascading dominoes.

The precise order of events was difficult to ascertain, but during that sequence the temperature of Greenland soared by 5°C to 16°C in decades to centuries. The question remains open: could such things happen today?

“The results emphasise the importance of trying to limit climate change by, for example, cutting anthropogenic emissions of CO2 and other greenhouse gases, both to reduce the predictable, gradual climate change and to reduce the risk of future abrupt climate change,” said Sune Olander Rasmussen, at the Niels Bohr Institute in Copenhagen, one of the authors.

Greenland’s future role

“If you do not want the dominoes to topple over, you are better off not to push the table they stand on too much.”

And another study in the same journal by British scientists reports on a close study of geological evidence to decipher the pattern of events during the largest and most rapid pulse of sea level rise at the close of the last Ice Age.

Their study suggested that although the sea levels rose 18 metres in about 500 years − a rate of about 3.6 metres a century − it all happened with relatively little help from a melting Antarctica. As the great glaciers retreated from North America, Europe and Asia, so the oceans rose.

“The next big question is to work out what triggered the ice melt, and what impact the massive influx of meltwater had on ocean currents in the North Atlantic,” said Pippa Whitehouse of the University of Durham, one of the researchers.

“This is very much on our minds today − any disruption to the Gulf Stream, for example due to melting of the Greenland Ice Sheet, will have significant consequences for the UK climate.” − Climate News Network

When the ice thaws, ocean levels rise. And four new studies show climate heating can happen fast.

LONDON, 15 April, 2021 − If climate heating continues apace and the planet goes on warming, then up to a third of Antarctica’s ice shelf could tip into the sea.

And tip is the operative word, according to a separate study: at least one Antarctic glacier could be about to tip into rapid and irreversible retreat if temperatures go on rising.

And rise they could: evidence from the past in a third research programme confirms that at the end of the last Ice Age, Greenland’s temperature rose by somewhere between 5°C and 16°C in just decades, in line with a cascade of climate change events.

And ominously a fourth study of climate change 14,600 years ago confirmed that as the ice retreated, sea levels rose at 10 times the current rate, to 3.6 metres in just a century, and up to 18 metres in a 500-year sequence.

Each study is, on its own, an examination of the complexities of the planetary climate machine and the role of the polar ice sheets in climate change. But the message of the four together is a stark one: climate change is happening, could accelerate and could happen at unexpected speeds.

Unstable at 4°C

The Antarctic ice sheet floats on the sea: were it all to melt, sea levels globally would remain much the same. But the ice sheet plays an important role in stabilising the massive reserves of ice on the continental surface.

“Ice shelves are important buffers preventing glaciers on land from flowing freely into the ocean and contributing to sea level rise,” warned Ella Gilbert, a meteorologist at the University of Reading in the UK. “When they collapse, it’s like a giant cork being removed from a bottle, allowing unimaginable amounts of water from glaciers to pour into the sea.”

She and colleagues report in the journal Geophysical Research Letters that their detailed study of the vulnerable platforms of floating ice around the continent revealed that half a million square kilometres of shelf − 34% in total, including two-thirds of all the ice off the Antarctic Peninsula − would become unstable if global temperatures rose by 4°C, under the business-as-usual scenario in which nations went on burning ever-greater quantities of fossil fuel.

If however the world kept to the limit it agreed in Paris in 2015, that would halve the area at risk and perhaps avoid significant sea level rise. But already, just two Antarctic glaciers are responsible for around 10% of sea level rise at the current rate, and researchers have been warning for years that the Pine Island and Thwaites glaciers in West Antarctica could be at risk.

Now researchers in the UK report in the journal The Cryosphere that their computer simulation had identified a series of tipping points for the Pine Island flow.

“Ice shelves are important buffers preventing glaciers on land from contributing to sea level rise. When they collapse, it’s like a giant cork being removed from a bottle, allowing unimaginable amounts of water to pour into the sea”

The third of these, triggered by ocean temperatures that had warmed just 1.2°C, would lead to irretrievable retreat of the entire glacier. Hilmar Gudmundsson, a glaciologist at the UK’s Northumbria University and one of the authors, called the research a “major step forward” in the understanding of the dynamics of the region.

“But the findings of this study also concern me”, he said. “Should the glacier enter unstable irreversible retreat, the impact on sea level could be measured in metres, and as this study shows, once the retreat starts it might be impossible to halt it.”

Rapid polar melt is part of the pattern of climate history. Danish researchers report in Nature Communications that, on the evidence preserved in Greenland ice cores, they identified a series of 30 abrupt climate changes at the close of the Last Ice Age, affecting North Atlantic ocean currents, wind and rainfall patterns and the spread of sea ice: a set of physical processes that changed together, like a row of cascading dominoes.

The precise order of events was difficult to ascertain, but during that sequence the temperature of Greenland soared by 5°C to 16°C in decades to centuries. The question remains open: could such things happen today?

“The results emphasise the importance of trying to limit climate change by, for example, cutting anthropogenic emissions of CO2 and other greenhouse gases, both to reduce the predictable, gradual climate change and to reduce the risk of future abrupt climate change,” said Sune Olander Rasmussen, at the Niels Bohr Institute in Copenhagen, one of the authors.

Greenland’s future role

“If you do not want the dominoes to topple over, you are better off not to push the table they stand on too much.”

And another study in the same journal by British scientists reports on a close study of geological evidence to decipher the pattern of events during the largest and most rapid pulse of sea level rise at the close of the last Ice Age.

Their study suggested that although the sea levels rose 18 metres in about 500 years − a rate of about 3.6 metres a century − it all happened with relatively little help from a melting Antarctica. As the great glaciers retreated from North America, Europe and Asia, so the oceans rose.

“The next big question is to work out what triggered the ice melt, and what impact the massive influx of meltwater had on ocean currents in the North Atlantic,” said Pippa Whitehouse of the University of Durham, one of the researchers.

“This is very much on our minds today − any disruption to the Gulf Stream, for example due to melting of the Greenland Ice Sheet, will have significant consequences for the UK climate.” − Climate News Network

Antarctic warming speed-up alarms researchers

The world’s largest reservoir of snow and ice could be melting faster than ever. Two new studies highlight Antarctic warming.

LONDON, 4 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.

“The high rates of increased glacier speed − coupled with ice thinning − confirm the Getz basin is losing more ice than it gains through snowfall”

US scientists report in the journal The Cryosphere that they too used satellite observation − 41 years of it − to measure summer meltwater on the ice and in the near-surface snow of the northern part of the George VI ice shelf. They identified the most widespread melt and the greatest total of melt days of any season during the 2019-2020 summer.

Air temperatures were above freezing for up to 90 hours, allowing pools of meltwater to collect on the shelf. At its peak 23% of the region was covered with water: the equivalent, in glaciology’s favourite popular measure, of 250,000 Olympic swimming pools.

“When the temperature is above zero degrees Celsius, that limits refreezing and also leads to further melting,” said Alison Banwell, of the University of Colorado at Boulder, who led the study. “Water absorbs more radiation than snow and ice, and that leads to even more melting.”

Remote and untrodden

The Getz shelf is one of the biggest of a sector of the West Antarctic known as Marie Byrd Land. A new report in Nature Communications confirms that all 14 measured glaciers there have picked up speed and reach the ocean ever more swiftly.

Three of them have accelerated by more than 44%. And over the years the loss of ice has been the equivalent of 126 million Olympic swimming pools − all of it now adding to global sea level rise.

“The Getz region of Antarctica is so remote that humans have never set foot on most of this part of the continent,” said Heather Selley, of the University of Leeds, UK, first author. “Satellite radar altimetry records have shown substantial thinning of the ice sheet.

“However, the high rates of increased glacier speed − coupled with ice thinning − now confirm the Getz basin is in dynamic imbalance, meaning that it is losing more ice than it gains through snowfall.” − Climate News Network

The world’s largest reservoir of snow and ice could be melting faster than ever. Two new studies highlight Antarctic warming.

LONDON, 4 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.

“The high rates of increased glacier speed − coupled with ice thinning − confirm the Getz basin is losing more ice than it gains through snowfall”

US scientists report in the journal The Cryosphere that they too used satellite observation − 41 years of it − to measure summer meltwater on the ice and in the near-surface snow of the northern part of the George VI ice shelf. They identified the most widespread melt and the greatest total of melt days of any season during the 2019-2020 summer.

Air temperatures were above freezing for up to 90 hours, allowing pools of meltwater to collect on the shelf. At its peak 23% of the region was covered with water: the equivalent, in glaciology’s favourite popular measure, of 250,000 Olympic swimming pools.

“When the temperature is above zero degrees Celsius, that limits refreezing and also leads to further melting,” said Alison Banwell, of the University of Colorado at Boulder, who led the study. “Water absorbs more radiation than snow and ice, and that leads to even more melting.”

Remote and untrodden

The Getz shelf is one of the biggest of a sector of the West Antarctic known as Marie Byrd Land. A new report in Nature Communications confirms that all 14 measured glaciers there have picked up speed and reach the ocean ever more swiftly.

Three of them have accelerated by more than 44%. And over the years the loss of ice has been the equivalent of 126 million Olympic swimming pools − all of it now adding to global sea level rise.

“The Getz region of Antarctica is so remote that humans have never set foot on most of this part of the continent,” said Heather Selley, of the University of Leeds, UK, first author. “Satellite radar altimetry records have shown substantial thinning of the ice sheet.

“However, the high rates of increased glacier speed − coupled with ice thinning − now confirm the Getz basin is in dynamic imbalance, meaning that it is losing more ice than it gains through snowfall.” − Climate News Network

Hope springs eternal for species facing extinction

Extinction is for ever, but not inevitable. Some threatened species are now surprising survivors. Can others follow suit?

LONDON, 22 February, 2021 − Scientists continue to issue strident warnings that the Earth faces a sixth mass extinction, and the evidence suggests they’re right.

There are some standout survivors, though − birds and mammals which not long ago appeared doomed but are now recovering. There is even a flickering hope that their resurgence could show the way to survival for some other species among the teeming millions at risk.

Researchers from the University of Newcastle, UK, and BirdLife International report in the journal Conservation Letters that different initiatives have prevented up to 32 bird and 16 mammal extinctions since 1993, the year the UN’s Convention on Biological Diversity entered into force.

As 10 bird and five mammal species are known to have become extinct in that time, the researchers think extinction rates would have been up to four times higher if humans had not acted to help the survivors.

“I think that’s a positive message. It’s not all bad news, always,” said Rike Bolam of the University of Newcastle, the study’s lead author. “It is encouraging that some of the species we studied have recovered very well.”

Success achieved

Stuart Butchart, chief scientist at BirdLife and an honorary research fellow in the zoology department of the University of Cambridge, said: “These results show that despite the overall failure to meet the targets for conserving nature set through the UN a decade ago, significant success in preventing extinctions was achieved.

“It would be easy to feel conservation was a pointless exercise and there’s nothing we can do to slow the juggernaut down. Broadly speaking, we have the tools, we just need much greater resource and political will.”

Many of the most successful conservation efforts involve what science knows as the charismatic megafauna, crowdpuller species such as the tiger, which may attract attention and funding relatively easily in their struggle to escape extinction. Most species do not.

But Bolam and Butchart’s team identified a number of recurring and widely applicable themes in trying to stem the catastrophic race towards oblivion: the removal of invasive species, for example, the management of hunting and protection of important habitats.

“We have the tools, we just need much greater resource and political will”

Saving the web of life intact to hand on to future generations the richness of species on which humanity depends won’t be easy. Adam Vaughan, chief reporter at the magazine New Scientist, writes: “Targeted actions won’t turn the tide alone. Stemming biodiversity loss will also require more fundamental changes to how we value nature – and whether those will be forthcoming is the trillion-dollar question.”

To give some idea of what works − and why − the magazine lists 10 survival success stories from around the world. It includes some obvious candidates, creatures which would be at the top of any keen zoologist’s bucket list − and probably most other people’s too. There’s the blue whale, obviously, its Antarctic sub-species reduced by hunters from an estimated 239,000 before industrial whaling started early in the last century to 360 by the early 1970s..

Yet by 2016 there were thought to be 4,500 in the southern ocean − something Jennifer Jackson at the British Antarctic Survey says has a wider lesson for conservation: “The blue whale recovery is symbolic of what humans can do if they just leave things alone.” Now, though, climate change is affecting the krill which are the whales’ main source of food. The possibility of extinction is returning.

China’s giant pandas declined fast in the 20th century. Political will and protected areas improved their prospects from “endangered” to “vulnerable.” The government has created 67 giant panda reserves since the 1960s, and in 1988 banned logging entirely in their habitats. “The determination and investment of the Chinese government is the key,” says Qiang Xu of WWF-China. But the pandas still need much more time before they’re safe.

Mountain gorilla numbers have risen from about 250 in 1981 to 1,063 today. Things were looking hopeful until last month, when a gorilla in a US zoo was found to have contracted Covid-19. Poaching and forest clearance for agriculture remain potent threats.

People matter

Indus river dolphins were once found along the entire 3,000 kms (1,860 miles) of the Indus, but their range fell to 1,300 kms (800 m). By 2001, their numbers had dropped to 1,200, largely because they become stranded and die in irrigation canals.

Acoustic devices help to deter the dolphins from entering the canals, but educating fishing communities and recruiting local people for ecotourism and monitoring has been the key to saving about 1,800 animals, says Uzma Khan of WWF-Pakistan. “I learned you cannot do anything without communities.”

Not every species on the New Scientist’s list will avoid extinction, let alone the countless others which will live and die unremarked. Not all of those listed is even a poster girl (or boy) for conservation.

The world’s most endangered primate, the Hainan gibbon, is endemic to the Chinese island of the same name, and probably not very widely-known. By 1980 its population had fallen from 2,000 to a total barely able to ensure survival − just nine animals. There are now thought to be around a slightly more secure 33 altogether. Wish them luck. − Climate New Network

Extinction is for ever, but not inevitable. Some threatened species are now surprising survivors. Can others follow suit?

LONDON, 22 February, 2021 − Scientists continue to issue strident warnings that the Earth faces a sixth mass extinction, and the evidence suggests they’re right.

There are some standout survivors, though − birds and mammals which not long ago appeared doomed but are now recovering. There is even a flickering hope that their resurgence could show the way to survival for some other species among the teeming millions at risk.

Researchers from the University of Newcastle, UK, and BirdLife International report in the journal Conservation Letters that different initiatives have prevented up to 32 bird and 16 mammal extinctions since 1993, the year the UN’s Convention on Biological Diversity entered into force.

As 10 bird and five mammal species are known to have become extinct in that time, the researchers think extinction rates would have been up to four times higher if humans had not acted to help the survivors.

“I think that’s a positive message. It’s not all bad news, always,” said Rike Bolam of the University of Newcastle, the study’s lead author. “It is encouraging that some of the species we studied have recovered very well.”

Success achieved

Stuart Butchart, chief scientist at BirdLife and an honorary research fellow in the zoology department of the University of Cambridge, said: “These results show that despite the overall failure to meet the targets for conserving nature set through the UN a decade ago, significant success in preventing extinctions was achieved.

“It would be easy to feel conservation was a pointless exercise and there’s nothing we can do to slow the juggernaut down. Broadly speaking, we have the tools, we just need much greater resource and political will.”

Many of the most successful conservation efforts involve what science knows as the charismatic megafauna, crowdpuller species such as the tiger, which may attract attention and funding relatively easily in their struggle to escape extinction. Most species do not.

But Bolam and Butchart’s team identified a number of recurring and widely applicable themes in trying to stem the catastrophic race towards oblivion: the removal of invasive species, for example, the management of hunting and protection of important habitats.

“We have the tools, we just need much greater resource and political will”

Saving the web of life intact to hand on to future generations the richness of species on which humanity depends won’t be easy. Adam Vaughan, chief reporter at the magazine New Scientist, writes: “Targeted actions won’t turn the tide alone. Stemming biodiversity loss will also require more fundamental changes to how we value nature – and whether those will be forthcoming is the trillion-dollar question.”

To give some idea of what works − and why − the magazine lists 10 survival success stories from around the world. It includes some obvious candidates, creatures which would be at the top of any keen zoologist’s bucket list − and probably most other people’s too. There’s the blue whale, obviously, its Antarctic sub-species reduced by hunters from an estimated 239,000 before industrial whaling started early in the last century to 360 by the early 1970s..

Yet by 2016 there were thought to be 4,500 in the southern ocean − something Jennifer Jackson at the British Antarctic Survey says has a wider lesson for conservation: “The blue whale recovery is symbolic of what humans can do if they just leave things alone.” Now, though, climate change is affecting the krill which are the whales’ main source of food. The possibility of extinction is returning.

China’s giant pandas declined fast in the 20th century. Political will and protected areas improved their prospects from “endangered” to “vulnerable.” The government has created 67 giant panda reserves since the 1960s, and in 1988 banned logging entirely in their habitats. “The determination and investment of the Chinese government is the key,” says Qiang Xu of WWF-China. But the pandas still need much more time before they’re safe.

Mountain gorilla numbers have risen from about 250 in 1981 to 1,063 today. Things were looking hopeful until last month, when a gorilla in a US zoo was found to have contracted Covid-19. Poaching and forest clearance for agriculture remain potent threats.

People matter

Indus river dolphins were once found along the entire 3,000 kms (1,860 miles) of the Indus, but their range fell to 1,300 kms (800 m). By 2001, their numbers had dropped to 1,200, largely because they become stranded and die in irrigation canals.

Acoustic devices help to deter the dolphins from entering the canals, but educating fishing communities and recruiting local people for ecotourism and monitoring has been the key to saving about 1,800 animals, says Uzma Khan of WWF-Pakistan. “I learned you cannot do anything without communities.”

Not every species on the New Scientist’s list will avoid extinction, let alone the countless others which will live and die unremarked. Not all of those listed is even a poster girl (or boy) for conservation.

The world’s most endangered primate, the Hainan gibbon, is endemic to the Chinese island of the same name, and probably not very widely-known. By 1980 its population had fallen from 2,000 to a total barely able to ensure survival − just nine animals. There are now thought to be around a slightly more secure 33 altogether. Wish them luck. − Climate New Network

Human rubbish is smothering the planet’s oceans

In a throwaway world garbage may be unseen, but not gone. Human rubbish is everywhere, from ocean abyss to coastal mud.

LONDON, 29 January, 2021 − In the next 30 years, an estimated three billion metric tonnes of human rubbish − everything from abandoned trawl nets to plastic bottles, from broken teacups to tins of toxin − could find its way into the sea, to defile the ocean floor.

One recent survey in the Strait of Messina, the seaway that separates Italy and Sicily, measured this detritus at concentrations of between 121,000 and 1.3 million items per square kilometre trapped in submarine canyons.

In seabed fissures off Portugal, bits of human litter large enough to identify have been counted at rates of 11,000 per sq km. Off the Ryukyu Islands far from mainland Japan, divers and remotely operated vehicles have made estimates of up to 71,000 items per sq km.

There is more and worse lying on other parts of the seabed. An estimated one million tonnes of chemical weaponry could be scattered about the planet’s oceans. The North Sea floor could be host to 1.3 million tonnes of conventional and chemical weapons; the Baltic enfolds and flows over 385,00 tonnes of dropped bombs, grenades, torpedoes, landmines and other weaponry.

“As humans, we have little or no care at all to prevent litter from accumulating everywhere”

And, says a new study in the journal Environmental Research Letters, this conversion of sea floor to careless landfill site creates problems for at least 693 marine species that so far have been observed to “interact” with marine debris: eat it, get caught in it, grow on it. Of these species, around one in six are in some degree endangered.

This list of sea creatures includes 93 kinds of invertebrate, 89 fish, 83 birds, 38 mammals and all species of sea turtle. So many fish now become ensnared in abandoned and derelict fishing gear that they are known as “ghost catches.”

Across the Asia-Pacific region, an estimated 11.1 billion bits of plastic bigger than 25mm could be entangled in the coral reefs. This problem of marine pollution goes far beyond the concern over plastic pollution of the planet’s seas and shores, from pole to pole, and is now found even in marine tissues.

Much of the previous concern has been about the presence of microfibres and small particles of polymer material now found everywhere. But the new study by European scientists tries to address the more obvious problem of these larger items − generally larger than 25mms − of all kinds of detritus, including plastic denser than water and ultimately destined to reach the seabed.

Poor management

The researchers want to try to find standard ways to measure the levels of waste, map its concentrations accurately, identify all the sources of refuse and classify the most problematic kinds: the toxic waste, the heavy metals and radioactive substances, the pharmaceuticals. They also urge international co-operation, and policies designed to discourage marine discharges and to clear up stretches of the sea floor.

“Marine litter has reached the most remote places in the ocean, even the least − or never − frequented by our species and not yet mapped by science,” said Miquel Canals of the University of Barcelona, who led the study.

“In order to correct something bad, we must attack its cause. And the cause of the accumulation of waste on the coasts, seas and oceans , and all over the planet, is the excess waste generation and spillage in the environment, and poor or insufficient management practices.

“As humans, we have little or no care at all to prevent litter from accumulating everywhere.” − Climate News Network

In a throwaway world garbage may be unseen, but not gone. Human rubbish is everywhere, from ocean abyss to coastal mud.

LONDON, 29 January, 2021 − In the next 30 years, an estimated three billion metric tonnes of human rubbish − everything from abandoned trawl nets to plastic bottles, from broken teacups to tins of toxin − could find its way into the sea, to defile the ocean floor.

One recent survey in the Strait of Messina, the seaway that separates Italy and Sicily, measured this detritus at concentrations of between 121,000 and 1.3 million items per square kilometre trapped in submarine canyons.

In seabed fissures off Portugal, bits of human litter large enough to identify have been counted at rates of 11,000 per sq km. Off the Ryukyu Islands far from mainland Japan, divers and remotely operated vehicles have made estimates of up to 71,000 items per sq km.

There is more and worse lying on other parts of the seabed. An estimated one million tonnes of chemical weaponry could be scattered about the planet’s oceans. The North Sea floor could be host to 1.3 million tonnes of conventional and chemical weapons; the Baltic enfolds and flows over 385,00 tonnes of dropped bombs, grenades, torpedoes, landmines and other weaponry.

“As humans, we have little or no care at all to prevent litter from accumulating everywhere”

And, says a new study in the journal Environmental Research Letters, this conversion of sea floor to careless landfill site creates problems for at least 693 marine species that so far have been observed to “interact” with marine debris: eat it, get caught in it, grow on it. Of these species, around one in six are in some degree endangered.

This list of sea creatures includes 93 kinds of invertebrate, 89 fish, 83 birds, 38 mammals and all species of sea turtle. So many fish now become ensnared in abandoned and derelict fishing gear that they are known as “ghost catches.”

Across the Asia-Pacific region, an estimated 11.1 billion bits of plastic bigger than 25mm could be entangled in the coral reefs. This problem of marine pollution goes far beyond the concern over plastic pollution of the planet’s seas and shores, from pole to pole, and is now found even in marine tissues.

Much of the previous concern has been about the presence of microfibres and small particles of polymer material now found everywhere. But the new study by European scientists tries to address the more obvious problem of these larger items − generally larger than 25mms − of all kinds of detritus, including plastic denser than water and ultimately destined to reach the seabed.

Poor management

The researchers want to try to find standard ways to measure the levels of waste, map its concentrations accurately, identify all the sources of refuse and classify the most problematic kinds: the toxic waste, the heavy metals and radioactive substances, the pharmaceuticals. They also urge international co-operation, and policies designed to discourage marine discharges and to clear up stretches of the sea floor.

“Marine litter has reached the most remote places in the ocean, even the least − or never − frequented by our species and not yet mapped by science,” said Miquel Canals of the University of Barcelona, who led the study.

“In order to correct something bad, we must attack its cause. And the cause of the accumulation of waste on the coasts, seas and oceans , and all over the planet, is the excess waste generation and spillage in the environment, and poor or insufficient management practices.

“As humans, we have little or no care at all to prevent litter from accumulating everywhere.” − Climate News Network

Scientists say world’s huge ice loss is speeding up

The frozen world is shrinking at a “staggering” rate. New research takes a measure of the world’s huge ice loss.

LONDON, 27 January, 2021 − Planet Earth is losing its frozen mantle faster than ever as the world’s huge ice loss intensifies. Between 1994 and 2017, the polar regions and the mountain glaciers said farewell to a total of 28 million million tonnes of ice. This is a quantity large enough to conceal the entire United Kingdom under an ice sheet 100 metres thick.

More alarmingly, scientists warn, the rate of loss has been accelerating. Over the course of the 23-year survey of the planet’s ice budget, there has been a 65% increase in the flow of meltwater from the glaciers, ice shelves and ice sheets.

Early in the last decade of the last century, ice loss was counted at 0.8 trillion tonnes a year. By 2017, this had increased to 1.3 trillion tonnes a year, says a new study in the journal The Cryosphere.

The finding should come as no great surprise. Thanks to profligate combustion of fossil fuels and the clearance of forests and grasslands, the planet is warming: 2020 has been awarded the unwelcome title of equal place as warmest year ever recorded, and the last six years have been the six warmest since records began.

“The vast majority of Earth’s ice loss is a direct consequence of climate warming.”

Researchers warned last year that the melting rate of Greenland’s ice sheet − the biggest in the northern hemisphere − would soon hit a 12,000 year high. A second group warned in the same month that ice loss from Antarctica would soon become irreversible.

The latest research, based on satellite data, confirms all fears. “Although every region we studied lost ice, losses from the Antarctic and Greenland ice sheets have accelerated the most,” said Thomas Slater, of the University of Leeds in the UK, who led the research.

“The ice sheets are now following the worst case climate warning scenarios set out by the Intergovernmental Panel on Climate Change. Sea level rise on this scale will have very serious impacts on coastal communities this century.”

The scientists measured loss from the land-based ice sheets of Greenland and Antarctica, from the shelf ice around Antarctica and from the drifting sea ice in the Arctic and Southern Oceans, as well as the retreat of 215,000 mountain glaciers worldwide.

‘Staggering’ loss

During the 23-year-survey, thanks to rising air and ocean temperatures, the Arctic Ocean lost 7.6 trillion tonnes, the Antarctic ice shelves 6.5 trillion tonnes. Melting sea ice will not affect sea levels, but it will expose greater areas of ocean to radiation, which would otherwise be reflected back into space. So the loss of sea ice can only lead to even more warming.

The researchers claim theirs is the first full global survey, but they also concede it can only be incomplete: they did not take the measure of fallen snow on land, nor of the icy soils of the permafrost, and they did not try to measure the loss of winter ice on lakes and rivers − but they note that the duration of ice on lakes has fallen by 12 days in the last two centuries, thanks to atmospheric warming.

However, they could put a measure on ice losses from land − 6.1 trillion tonnes from mountain glaciers worldwide, 3.8 trillion tonnes from the Greenland ice sheet, 2.5 trillion tonnes from the Antarctic surface − enough to raise global sea levels by 35mm.

Scientific studies tend to be presented without emotive language. But the researchers call their total of lost ice “staggering”. And they warn: “There can be little doubt that the vast majority of Earth’s ice loss is a direct consequence of climate warming.” − Climate News Network

The frozen world is shrinking at a “staggering” rate. New research takes a measure of the world’s huge ice loss.

LONDON, 27 January, 2021 − Planet Earth is losing its frozen mantle faster than ever as the world’s huge ice loss intensifies. Between 1994 and 2017, the polar regions and the mountain glaciers said farewell to a total of 28 million million tonnes of ice. This is a quantity large enough to conceal the entire United Kingdom under an ice sheet 100 metres thick.

More alarmingly, scientists warn, the rate of loss has been accelerating. Over the course of the 23-year survey of the planet’s ice budget, there has been a 65% increase in the flow of meltwater from the glaciers, ice shelves and ice sheets.

Early in the last decade of the last century, ice loss was counted at 0.8 trillion tonnes a year. By 2017, this had increased to 1.3 trillion tonnes a year, says a new study in the journal The Cryosphere.

The finding should come as no great surprise. Thanks to profligate combustion of fossil fuels and the clearance of forests and grasslands, the planet is warming: 2020 has been awarded the unwelcome title of equal place as warmest year ever recorded, and the last six years have been the six warmest since records began.

“The vast majority of Earth’s ice loss is a direct consequence of climate warming.”

Researchers warned last year that the melting rate of Greenland’s ice sheet − the biggest in the northern hemisphere − would soon hit a 12,000 year high. A second group warned in the same month that ice loss from Antarctica would soon become irreversible.

The latest research, based on satellite data, confirms all fears. “Although every region we studied lost ice, losses from the Antarctic and Greenland ice sheets have accelerated the most,” said Thomas Slater, of the University of Leeds in the UK, who led the research.

“The ice sheets are now following the worst case climate warning scenarios set out by the Intergovernmental Panel on Climate Change. Sea level rise on this scale will have very serious impacts on coastal communities this century.”

The scientists measured loss from the land-based ice sheets of Greenland and Antarctica, from the shelf ice around Antarctica and from the drifting sea ice in the Arctic and Southern Oceans, as well as the retreat of 215,000 mountain glaciers worldwide.

‘Staggering’ loss

During the 23-year-survey, thanks to rising air and ocean temperatures, the Arctic Ocean lost 7.6 trillion tonnes, the Antarctic ice shelves 6.5 trillion tonnes. Melting sea ice will not affect sea levels, but it will expose greater areas of ocean to radiation, which would otherwise be reflected back into space. So the loss of sea ice can only lead to even more warming.

The researchers claim theirs is the first full global survey, but they also concede it can only be incomplete: they did not take the measure of fallen snow on land, nor of the icy soils of the permafrost, and they did not try to measure the loss of winter ice on lakes and rivers − but they note that the duration of ice on lakes has fallen by 12 days in the last two centuries, thanks to atmospheric warming.

However, they could put a measure on ice losses from land − 6.1 trillion tonnes from mountain glaciers worldwide, 3.8 trillion tonnes from the Greenland ice sheet, 2.5 trillion tonnes from the Antarctic surface − enough to raise global sea levels by 35mm.

Scientific studies tend to be presented without emotive language. But the researchers call their total of lost ice “staggering”. And they warn: “There can be little doubt that the vast majority of Earth’s ice loss is a direct consequence of climate warming.” − Climate News Network

Polar link unites far extremes of north and south

They are different worlds, one an ocean, the other a continent. But a polar link keeps them in touch with each other.

LONDON, 30 November, 2020 − The Arctic and Antarctica are literally a world apart, but for an unlikely polar link. Change in the mass of ice in the north can and does precipitate change in the furthest reaches of the southern hemisphere.

According to 40,000 years of geological evidence, when the Arctic Ocean ice retreats, global sea levels rise to start washing away the sea ice around the shelf of the vast frozen continent at the other extreme of the planet.

This pattern of action at a distance is confirmed by computer simulations: the planet’s two hemispheres are in a kind of conversation, according to a new study in the journal Nature.

“Our results highlight how interconnected the Earth system is, with changes in one part of the planet driving changes in another,” said Natalya Gomez, of McGill University in Canada, who led the study.

“In the modern era, we haven’t seen the kind of large ice sheet retreat that we might see in our future warming world. Looking to records and models of change in Earth’s history can inform us about this.”

“Ice sheets can influence each other over great distances. It’s as though they were talking to one another about sea level changes”

The Arctic is one of the fastest-warming places on the planet: what happens in the far north has reverberations throughout the hemisphere. And Antarctica, too, is changing swiftly.

Although both extremes of cold are vulnerable to global heating driven by profligate fossil fuel use and global-scale loss of forests, climate scientists have tended to consider them as separate cases.

But a closer look at geological records − ice cores and samples from the ocean bottom that offer evidence of iceberg drift across the millennia − revealed a connection. The polar link is real.

At the height of the last ice age more than 20,000 years ago, the mass of ice in the north lowered global sea levels and the Antarctic ice shelf advanced. As the world began to warm again, ice in the north began to flow into the sea. Sea levels rose in the southern hemisphere and this began to force a retreat of the Antarctic ice.

“Ice sheets can influence each other over great distances due to the water that flows between them. It’s as though they were talking to one another about sea level changes,” Dr Gomez said.

Dynamic ice

“Polar ice sheets are not just large static mounds of ice. They evolve on various different time scales and are in constant flux, with ice growing and retreating, depending on the climate and the surrounding water levels.

“They gain ice as snow piles up on top of them, then spread outwards under their own weight, and stream out into the surrounding ocean where their edges break off into icebergs.”

The evidence showed that sea level change in Antarctica and ice mass loss in the Arctic were linked, over a sequence of at least 40,000 years.

“These ice sheets are really dynamic, exciting and intriguing parts of the Earth’s climate system. It’s staggering to think of ice that is several kilometres thick, that covers an entire continent, and that is evolving on all of these different timescales with global consequences,” Dr Gomez said.

“It’s just motivation for trying to better understand these really massive systems that are so far away from us.” − Climate News Network

They are different worlds, one an ocean, the other a continent. But a polar link keeps them in touch with each other.

LONDON, 30 November, 2020 − The Arctic and Antarctica are literally a world apart, but for an unlikely polar link. Change in the mass of ice in the north can and does precipitate change in the furthest reaches of the southern hemisphere.

According to 40,000 years of geological evidence, when the Arctic Ocean ice retreats, global sea levels rise to start washing away the sea ice around the shelf of the vast frozen continent at the other extreme of the planet.

This pattern of action at a distance is confirmed by computer simulations: the planet’s two hemispheres are in a kind of conversation, according to a new study in the journal Nature.

“Our results highlight how interconnected the Earth system is, with changes in one part of the planet driving changes in another,” said Natalya Gomez, of McGill University in Canada, who led the study.

“In the modern era, we haven’t seen the kind of large ice sheet retreat that we might see in our future warming world. Looking to records and models of change in Earth’s history can inform us about this.”

“Ice sheets can influence each other over great distances. It’s as though they were talking to one another about sea level changes”

The Arctic is one of the fastest-warming places on the planet: what happens in the far north has reverberations throughout the hemisphere. And Antarctica, too, is changing swiftly.

Although both extremes of cold are vulnerable to global heating driven by profligate fossil fuel use and global-scale loss of forests, climate scientists have tended to consider them as separate cases.

But a closer look at geological records − ice cores and samples from the ocean bottom that offer evidence of iceberg drift across the millennia − revealed a connection. The polar link is real.

At the height of the last ice age more than 20,000 years ago, the mass of ice in the north lowered global sea levels and the Antarctic ice shelf advanced. As the world began to warm again, ice in the north began to flow into the sea. Sea levels rose in the southern hemisphere and this began to force a retreat of the Antarctic ice.

“Ice sheets can influence each other over great distances due to the water that flows between them. It’s as though they were talking to one another about sea level changes,” Dr Gomez said.

Dynamic ice

“Polar ice sheets are not just large static mounds of ice. They evolve on various different time scales and are in constant flux, with ice growing and retreating, depending on the climate and the surrounding water levels.

“They gain ice as snow piles up on top of them, then spread outwards under their own weight, and stream out into the surrounding ocean where their edges break off into icebergs.”

The evidence showed that sea level change in Antarctica and ice mass loss in the Arctic were linked, over a sequence of at least 40,000 years.

“These ice sheets are really dynamic, exciting and intriguing parts of the Earth’s climate system. It’s staggering to think of ice that is several kilometres thick, that covers an entire continent, and that is evolving on all of these different timescales with global consequences,” Dr Gomez said.

“It’s just motivation for trying to better understand these really massive systems that are so far away from us.” − Climate News Network

Antarctic depths warm far beyond oceanic average

Heat from factories and car exhausts must go somewhere. A surprising amount is now sunk in the remote Antarctic depths.

LONDON, 28 October, 2020 − Thanks to global heating, a vital part of the Southern Ocean is warming at a rate five times faster than the average for the Blue Planet as a whole, in the far Antarctic depths: 2000 metres or more below the surface of the Weddell Sea.

It is happening because at that depth the Weddell Sea has absorbed five times as much atmospheric heat − fuelled by greenhouse gas emissions from human fossil fuel combustion − as the average for the rest of the ocean. But what happens out of sight and far below the surface may not stay invisible. The Weddell Sea is where vast volumes of water circulate.

The fear is that such dramatic warming at depth could end up weakening a powerful current that encircles Antarctica, according to a new study in the Journal of Climate.

The evidence comes from 30 years of temperature and salinity samples, taken at the same spot and through the entire water column, with exquisite accuracy, by scientists aboard the German research icebreaker Polarstern.

“Our time series confirms the pivotal role of the Southern Ocean and especially the Weddell Sea in terms of storing heat in the depths of the world’s oceans”

“Our data shows a clear division in the water column of the Weddell Sea. While the water in the upper 700 metres has hardly warmed at all, in the deeper regions we’re seeing a consistent temperature rise of 0.0021 to 0.0024 degrees Celsius per year,” said Volker Strass, of the Alfred Wegener Institute in Bremerhaven in Germany.

“Since the ocean has roughly 1,000 times the heat capacity of the atmosphere, these numbers represent an enormous scale of heat absorption. By using the temperature rise to calculate the warming rate in watts per square metre, you can see that over the past 30 years, at depths of over 2,000 metres, the Weddell Sea has absorbed five times as much heat as the rest of the ocean on average.”

The global ocean is the great absorber of atmospheric shock. The deep blue sea has so far absorbed more than nine-tenths of the heat trapped by greenhouse gas emissions in the atmosphere.

The Weddell Sea begins at the extreme south of the Atlantic Ocean: it is roughly 10 times the size of Europe’s North Sea. Here tremendous volumes of water cool down. As sea ice forms on the surface the remaining waters become more salty, and because they have become colder, and denser, sink to the bottom, to spread at depth to drive deep sea flow into the oceans.

Ocean circulation risk

This act of overturning − the sinking of surface waters for thousands of metres into the Antarctic depths − is part of the machinery of ocean circulation that drives and modifies the world’s weather systems, and the climate.

The problem is that if the bottom waters are warming − and are therefore less dense − then this could weaken or stall the mechanism for ocean circulation. In the past 30 years the prevailing winds have shifted and intensified, and the flow speed of ocean water has increased to deliver more heat to the Weddell Sea with each decade.

Warming ocean waters have already been implicated in the loss of sea ice  cover that normally slows the flow of Antarctica’s continental glaciers. And warming in the Arctic has already triggered worries about the future of the “Atlantic Conveyer,” that enormous circulation of water that distributes heat from the Equator to the Poles and keeps northern Europe much warmer than its latitudes would dictate.

“Our time series confirms the pivotal role of the Southern Ocean and especially the Weddell Sea in terms of storing heat in the depths of the world’s oceans,” said Dr Strass. − Climate News Network

Heat from factories and car exhausts must go somewhere. A surprising amount is now sunk in the remote Antarctic depths.

LONDON, 28 October, 2020 − Thanks to global heating, a vital part of the Southern Ocean is warming at a rate five times faster than the average for the Blue Planet as a whole, in the far Antarctic depths: 2000 metres or more below the surface of the Weddell Sea.

It is happening because at that depth the Weddell Sea has absorbed five times as much atmospheric heat − fuelled by greenhouse gas emissions from human fossil fuel combustion − as the average for the rest of the ocean. But what happens out of sight and far below the surface may not stay invisible. The Weddell Sea is where vast volumes of water circulate.

The fear is that such dramatic warming at depth could end up weakening a powerful current that encircles Antarctica, according to a new study in the Journal of Climate.

The evidence comes from 30 years of temperature and salinity samples, taken at the same spot and through the entire water column, with exquisite accuracy, by scientists aboard the German research icebreaker Polarstern.

“Our time series confirms the pivotal role of the Southern Ocean and especially the Weddell Sea in terms of storing heat in the depths of the world’s oceans”

“Our data shows a clear division in the water column of the Weddell Sea. While the water in the upper 700 metres has hardly warmed at all, in the deeper regions we’re seeing a consistent temperature rise of 0.0021 to 0.0024 degrees Celsius per year,” said Volker Strass, of the Alfred Wegener Institute in Bremerhaven in Germany.

“Since the ocean has roughly 1,000 times the heat capacity of the atmosphere, these numbers represent an enormous scale of heat absorption. By using the temperature rise to calculate the warming rate in watts per square metre, you can see that over the past 30 years, at depths of over 2,000 metres, the Weddell Sea has absorbed five times as much heat as the rest of the ocean on average.”

The global ocean is the great absorber of atmospheric shock. The deep blue sea has so far absorbed more than nine-tenths of the heat trapped by greenhouse gas emissions in the atmosphere.

The Weddell Sea begins at the extreme south of the Atlantic Ocean: it is roughly 10 times the size of Europe’s North Sea. Here tremendous volumes of water cool down. As sea ice forms on the surface the remaining waters become more salty, and because they have become colder, and denser, sink to the bottom, to spread at depth to drive deep sea flow into the oceans.

Ocean circulation risk

This act of overturning − the sinking of surface waters for thousands of metres into the Antarctic depths − is part of the machinery of ocean circulation that drives and modifies the world’s weather systems, and the climate.

The problem is that if the bottom waters are warming − and are therefore less dense − then this could weaken or stall the mechanism for ocean circulation. In the past 30 years the prevailing winds have shifted and intensified, and the flow speed of ocean water has increased to deliver more heat to the Weddell Sea with each decade.

Warming ocean waters have already been implicated in the loss of sea ice  cover that normally slows the flow of Antarctica’s continental glaciers. And warming in the Arctic has already triggered worries about the future of the “Atlantic Conveyer,” that enormous circulation of water that distributes heat from the Equator to the Poles and keeps northern Europe much warmer than its latitudes would dictate.

“Our time series confirms the pivotal role of the Southern Ocean and especially the Weddell Sea in terms of storing heat in the depths of the world’s oceans,” said Dr Strass. − Climate News Network

Antarctica’s ice loss could soon be irreversible

Global heating means the southern ice will melt. Antarctica’s ice loss could then be permanent, drowning many great cities.

LONDON, 2 October, 2020 – The greatest mass of ice on the planet is growing steadily more unstable, and that means Antarctica’s ice loss may before long be inexorable.

New studies show that right now, just one degree of warming must mean an eventual sea level rise of 1.3 metres, simply from the flow of melting ice from the continent of Antarctica.

If the annual average temperature of the planet goes beyond 2°C, then the Antarctic melting rate will double. And when global heating really steps up to 6°C or beyond, melting accelerates to the almost unimaginable level of 10 metres for every single degree rise in planetary average temperatures.

And, the researchers say, there is no way back. Even if the world’s nations stick to a promise made in Paris in 2015, to keep global heating to “well below” 2°C by the end of the century, the losses of the southern polar ice sheet cannot be restored: the process of melting, once triggered by global temperature rise, becomes inexorable.

European and US researchers report in the journal Nature that they worked through ice core records of long-ago change in Antarctica and employed a million hours of computer simulation time to build up a reliable picture of change on the Antarctic continent, in response to ever-higher planetary average temperatures, driven by ever more profligate use of fossil fuels to generate ever-higher atmospheric ratios of greenhouse gases.

Their word for the state they wanted to study is hysteresis: this can be interpreted as the way altered conditions might commit a state to further change.

“If we give up the Paris Agreement, we give up Hamburg, Tokyo and New York”

The planet’s climate has oscillated many times over many millions of years. What this climate shift does to the polar regions can literally change the map of the planet. Antarctica is an enormous continent, the size of the US, Mexico and India together, and the ice it bears would, if it all were to melt, raise global sea levels by 58 metres.

“Antarctica holds more than half of Earth’s fresh water, frozen in a vast ice-sheet which is nearly five kilometres thick. As the surrounding ocean water and atmosphere warm due to human greenhouse gas emissions, the white cap on the South Pole loses mass and eventually becomes unstable,” said Ricarda Winkelmann, of the Potsdam Institute for Climate Impact Research.

“Because of its sheer magnitude, Antarctica’s potential for sea level contribution is enormous. We find that already at two degrees of warming, melting and the accelerated ice flow into the ocean will, eventually, entail 2.5 metres of global sea level rise just from Antarctica alone. At four degrees, it will be 6.5 metres and at six degrees almost 12 metres, if these temperature levels would be sustained long enough.”

That loss of ice would be slow – it would take many thousands of years – but the point the researchers make is that the continent may already be nearing a tipping point, after which the slide towards ever-higher sea levels would be unstoppable.

Since the great ice sheets of Greenland and Antarctica are part of the planetary cooling system – their whiteness reflects solar radiation back into space, so that the ice becomes its own insulation – their loss would inevitably trigger the process of further and faster warming.

Scientists from all nations have been warning for more than a decade that the continent is losing its protective screen of seaborne shelf ice, which in turn would make glacier flow towards the sea ever faster, and that the rate of loss of ice has begun to accelerate.

No going back

“In the end, it is our burning of coal and oil that determines ongoing and future greenhouse gas emissions and, therefore, if and when critical temperature thresholds in Antarctica are crossed.

“And even if the ice loss happens on long time scales, the respective carbon dioxide levels can already be reached in the near future,” said Professor Winkelmann.

“We decide now whether we manage to halt the warming. So Antarctica’s fate really lies in our hands – and with it that of our cities and cultural sites across the globe, from Rio de Janeiro’s Copacabana to Sydney’s Opera House. Thus this study really is another exclamation mark behind the importance of the Paris Climate Accord: Keep global warming below two degrees.”

And her Potsdam co-author Anders Levermann reinforced the argument. “Our simulations show that once it’s melted, it does not regrow to its initial state even if temperatures eventually sank again.

“Indeed, temperatures would have to go back to pre-industrial levels to allow its full recovery – a highly unlikely scenario. In other words: what we lose of Antarctica now is lost forever.”

And he warned: “If we give up the Paris Agreement, we give up Hamburg, Tokyo and New York.” – Climate News Network

Global heating means the southern ice will melt. Antarctica’s ice loss could then be permanent, drowning many great cities.

LONDON, 2 October, 2020 – The greatest mass of ice on the planet is growing steadily more unstable, and that means Antarctica’s ice loss may before long be inexorable.

New studies show that right now, just one degree of warming must mean an eventual sea level rise of 1.3 metres, simply from the flow of melting ice from the continent of Antarctica.

If the annual average temperature of the planet goes beyond 2°C, then the Antarctic melting rate will double. And when global heating really steps up to 6°C or beyond, melting accelerates to the almost unimaginable level of 10 metres for every single degree rise in planetary average temperatures.

And, the researchers say, there is no way back. Even if the world’s nations stick to a promise made in Paris in 2015, to keep global heating to “well below” 2°C by the end of the century, the losses of the southern polar ice sheet cannot be restored: the process of melting, once triggered by global temperature rise, becomes inexorable.

European and US researchers report in the journal Nature that they worked through ice core records of long-ago change in Antarctica and employed a million hours of computer simulation time to build up a reliable picture of change on the Antarctic continent, in response to ever-higher planetary average temperatures, driven by ever more profligate use of fossil fuels to generate ever-higher atmospheric ratios of greenhouse gases.

Their word for the state they wanted to study is hysteresis: this can be interpreted as the way altered conditions might commit a state to further change.

“If we give up the Paris Agreement, we give up Hamburg, Tokyo and New York”

The planet’s climate has oscillated many times over many millions of years. What this climate shift does to the polar regions can literally change the map of the planet. Antarctica is an enormous continent, the size of the US, Mexico and India together, and the ice it bears would, if it all were to melt, raise global sea levels by 58 metres.

“Antarctica holds more than half of Earth’s fresh water, frozen in a vast ice-sheet which is nearly five kilometres thick. As the surrounding ocean water and atmosphere warm due to human greenhouse gas emissions, the white cap on the South Pole loses mass and eventually becomes unstable,” said Ricarda Winkelmann, of the Potsdam Institute for Climate Impact Research.

“Because of its sheer magnitude, Antarctica’s potential for sea level contribution is enormous. We find that already at two degrees of warming, melting and the accelerated ice flow into the ocean will, eventually, entail 2.5 metres of global sea level rise just from Antarctica alone. At four degrees, it will be 6.5 metres and at six degrees almost 12 metres, if these temperature levels would be sustained long enough.”

That loss of ice would be slow – it would take many thousands of years – but the point the researchers make is that the continent may already be nearing a tipping point, after which the slide towards ever-higher sea levels would be unstoppable.

Since the great ice sheets of Greenland and Antarctica are part of the planetary cooling system – their whiteness reflects solar radiation back into space, so that the ice becomes its own insulation – their loss would inevitably trigger the process of further and faster warming.

Scientists from all nations have been warning for more than a decade that the continent is losing its protective screen of seaborne shelf ice, which in turn would make glacier flow towards the sea ever faster, and that the rate of loss of ice has begun to accelerate.

No going back

“In the end, it is our burning of coal and oil that determines ongoing and future greenhouse gas emissions and, therefore, if and when critical temperature thresholds in Antarctica are crossed.

“And even if the ice loss happens on long time scales, the respective carbon dioxide levels can already be reached in the near future,” said Professor Winkelmann.

“We decide now whether we manage to halt the warming. So Antarctica’s fate really lies in our hands – and with it that of our cities and cultural sites across the globe, from Rio de Janeiro’s Copacabana to Sydney’s Opera House. Thus this study really is another exclamation mark behind the importance of the Paris Climate Accord: Keep global warming below two degrees.”

And her Potsdam co-author Anders Levermann reinforced the argument. “Our simulations show that once it’s melted, it does not regrow to its initial state even if temperatures eventually sank again.

“Indeed, temperatures would have to go back to pre-industrial levels to allow its full recovery – a highly unlikely scenario. In other words: what we lose of Antarctica now is lost forever.”

And he warned: “If we give up the Paris Agreement, we give up Hamburg, Tokyo and New York.” – Climate News Network

South Pole warms faster than anywhere − but why?

The coldest place on Earth, the South Pole, is mysteriously heating a lot faster than the rest of the planet.

LONDON, 16 July, 2020 − The South Pole is warming, and warming fast. In the last 30 years, the place furthest from the summer sun, the place where one winter’s night lasts for 179 days, has been warming at 0.6°C per decade. This is three times the speed of average warming for the whole planet.

The finding is unexpected. The geographic South Pole is not only the most extreme location in the southern hemisphere, it is also at Alpine altitude. The Amundsen-Scott research station at the pole is at 2,835 metres, perched on a sheet of glacier ice 2,700 metres above the bedrock, and moving towards the sea at 10 metres a year.

Winter temperatures have fallen to minus 82.8°C. The warmest summer day ever recorded was minus 13.6°C.

And yet this unforgiving spot, with an annual average temperature of minus 49°C, still registers a measure of global warming. Whether this warming is fuelled by a natural climate cycle or by the profligate human use of fossil fuels, or by both, is not certain.

Systematic record-keeping began only in 1957 and for most of the late 20th century, while the rest of the planet started to warm, the South Pole continued to cool. West Antarctica is getting warmer, and melting at an accelerating rate, thanks in part to human-fuelled climate change.

“Antarctica experiences some of the most extreme weather and variability on the planet, and due to its remote location we actually know very little about the continent”

But scientists from New Zealand and the US report in the journal Nature that between 1989 and 2018, the South Pole had warmed by 1.8°C, partly because warm waters in the western Pacific had affected the South Atlantic winds and stepped up the delivery of warm air to the heart of the continent.

And this most extreme of environments goes on presenting puzzles. In April researchers announced the discovery of the remains of a 90-million-year-old swampy temperate forest within 900kms of the South Pole: it was once so warm that even in a winter night that lasted for months, foliage could flourish.

The latest research from the South Pole data suggests that researchers would like to know a lot more before they can say if the warming trend will continue, and why.

“Antarctica experiences some of the most extreme weather and variability on the planet,” said Kyle Clem, of Victoria University in Wellington, New Zealand, who led the research, “and due to its remote location we actually know very little about the continent, so there are constant surprises and new things to learn about Antarctica every year.” − Climate News Network

The coldest place on Earth, the South Pole, is mysteriously heating a lot faster than the rest of the planet.

LONDON, 16 July, 2020 − The South Pole is warming, and warming fast. In the last 30 years, the place furthest from the summer sun, the place where one winter’s night lasts for 179 days, has been warming at 0.6°C per decade. This is three times the speed of average warming for the whole planet.

The finding is unexpected. The geographic South Pole is not only the most extreme location in the southern hemisphere, it is also at Alpine altitude. The Amundsen-Scott research station at the pole is at 2,835 metres, perched on a sheet of glacier ice 2,700 metres above the bedrock, and moving towards the sea at 10 metres a year.

Winter temperatures have fallen to minus 82.8°C. The warmest summer day ever recorded was minus 13.6°C.

And yet this unforgiving spot, with an annual average temperature of minus 49°C, still registers a measure of global warming. Whether this warming is fuelled by a natural climate cycle or by the profligate human use of fossil fuels, or by both, is not certain.

Systematic record-keeping began only in 1957 and for most of the late 20th century, while the rest of the planet started to warm, the South Pole continued to cool. West Antarctica is getting warmer, and melting at an accelerating rate, thanks in part to human-fuelled climate change.

“Antarctica experiences some of the most extreme weather and variability on the planet, and due to its remote location we actually know very little about the continent”

But scientists from New Zealand and the US report in the journal Nature that between 1989 and 2018, the South Pole had warmed by 1.8°C, partly because warm waters in the western Pacific had affected the South Atlantic winds and stepped up the delivery of warm air to the heart of the continent.

And this most extreme of environments goes on presenting puzzles. In April researchers announced the discovery of the remains of a 90-million-year-old swampy temperate forest within 900kms of the South Pole: it was once so warm that even in a winter night that lasted for months, foliage could flourish.

The latest research from the South Pole data suggests that researchers would like to know a lot more before they can say if the warming trend will continue, and why.

“Antarctica experiences some of the most extreme weather and variability on the planet,” said Kyle Clem, of Victoria University in Wellington, New Zealand, who led the research, “and due to its remote location we actually know very little about the continent, so there are constant surprises and new things to learn about Antarctica every year.” − Climate News Network

Antarctic melting could bring a much hotter future

Antarctic melting can force sea ice retreat of 50 metres daily. CO2 levels are at their highest for 23 million years. Learn from the past.

LONDON, 23 June, 2020 – Antarctic melting starts with dramatic speed. Ice shelves during the sudden warm spell at the close of the last Ice Age retreated at up to 50 metres a day.

This finding is not based on climate simulations generated by computer algorithms. It is based on direct evidence left 12,000 years ago on the Antarctic sea floor by retreating ice.

The finding is an indirect indicator of how warm things could get – and how high sea levels could rise – as humans burn ever more fossil fuels and raise atmospheric greenhouse gas levels to ever higher ratios.

And as if to highlight the approaching climate catastrophe, a second and separate study finds that the measure of carbon dioxide in the atmosphere now is not just higher than at any time in human history or at any interval in the Ice Ages. It is the highest for at least 23 million years.

“Should climate change continue to weaken the ice shelves in the coming decades, we could see similar rates of retreat, with profound implications for global sea level rise”

British scientists report in the journal Science that they used an autonomous underwater vehicle (AUV), cruising at depth in the Weddell Sea, to read the pattern of the past preserved in ridges of the Antarctic seabed.

The original push for the expedition had been to search for the ship Endurance, commanded by the polar explorer Ernest Shackleton on his doomed voyage in 1914. The loss of the ship, crushed in the polar ice, and the rescue of his crew became one of the epic stories of maritime history.

The researchers did not find Endurance. But they did find an enduring record of past ice retreat.

Sea ice skirts about 75% of the continent’s coastline: when it melts it makes no difference to sea levels, but while it remains frozen it does serve the purpose of buttressing glacial flow from the high Antarctic interior. Brushed by increasingly warm air each summer, and swept by slowly warming ocean currents all year round, the ice shelves are thinning and retreating.

Tell-tale line

Underneath the ice, the research team’s robot submarine spotted wave-like ridges, each about a metre high and 20 to 25 metres apart: ridges formed at what had once been the grounding line – the point at which a grounded ice sheet starts to float, and evidence of ice rising and falling with the tides.

There are twelve hours between high tide and low, so by measuring the distance between the ridges, scientists could measure the pace of retreat at the end of the last Ice Age. It is estimated at 40 to 50 metres a day.

Right now, the fastest retreat measured from grounding lines in Antarctica is only about 1.6 kms a year. The implication is that it could get a lot faster.

“Should climate change continue to weaken the ice shelves in the coming decades, we could see similar rates of retreat, with profound implications for global sea level rise,” said Julian Dowdeswell, director of the Scott Polar Research Institute in Cambridge, who led the research.

Faster change ahead

Past warm periods are associated only with relatively modest rises in atmospheric carbon dioxide. Right now, researchers have repeatedly confirmed that the present increasingly rapid rise is the highest in the last 800,000 years.

Now a team from the US and Norway report in the journal Geology that they have measured past atmospheric carbon levels in fossil plants to establish that present day carbon levels are higher currently than at any time in the last 23 million years.

This means that – unless there are drastic steps to contain global warming – the retreat will become increasingly more rapid, and the rate of glacial flow towards the sea ever faster.

Were all the ice in Antarctica to melt, sea levels would rise by about 60 metres, completely submerging many of the world’s great cities. – Climate News Network

Antarctic melting can force sea ice retreat of 50 metres daily. CO2 levels are at their highest for 23 million years. Learn from the past.

LONDON, 23 June, 2020 – Antarctic melting starts with dramatic speed. Ice shelves during the sudden warm spell at the close of the last Ice Age retreated at up to 50 metres a day.

This finding is not based on climate simulations generated by computer algorithms. It is based on direct evidence left 12,000 years ago on the Antarctic sea floor by retreating ice.

The finding is an indirect indicator of how warm things could get – and how high sea levels could rise – as humans burn ever more fossil fuels and raise atmospheric greenhouse gas levels to ever higher ratios.

And as if to highlight the approaching climate catastrophe, a second and separate study finds that the measure of carbon dioxide in the atmosphere now is not just higher than at any time in human history or at any interval in the Ice Ages. It is the highest for at least 23 million years.

“Should climate change continue to weaken the ice shelves in the coming decades, we could see similar rates of retreat, with profound implications for global sea level rise”

British scientists report in the journal Science that they used an autonomous underwater vehicle (AUV), cruising at depth in the Weddell Sea, to read the pattern of the past preserved in ridges of the Antarctic seabed.

The original push for the expedition had been to search for the ship Endurance, commanded by the polar explorer Ernest Shackleton on his doomed voyage in 1914. The loss of the ship, crushed in the polar ice, and the rescue of his crew became one of the epic stories of maritime history.

The researchers did not find Endurance. But they did find an enduring record of past ice retreat.

Sea ice skirts about 75% of the continent’s coastline: when it melts it makes no difference to sea levels, but while it remains frozen it does serve the purpose of buttressing glacial flow from the high Antarctic interior. Brushed by increasingly warm air each summer, and swept by slowly warming ocean currents all year round, the ice shelves are thinning and retreating.

Tell-tale line

Underneath the ice, the research team’s robot submarine spotted wave-like ridges, each about a metre high and 20 to 25 metres apart: ridges formed at what had once been the grounding line – the point at which a grounded ice sheet starts to float, and evidence of ice rising and falling with the tides.

There are twelve hours between high tide and low, so by measuring the distance between the ridges, scientists could measure the pace of retreat at the end of the last Ice Age. It is estimated at 40 to 50 metres a day.

Right now, the fastest retreat measured from grounding lines in Antarctica is only about 1.6 kms a year. The implication is that it could get a lot faster.

“Should climate change continue to weaken the ice shelves in the coming decades, we could see similar rates of retreat, with profound implications for global sea level rise,” said Julian Dowdeswell, director of the Scott Polar Research Institute in Cambridge, who led the research.

Faster change ahead

Past warm periods are associated only with relatively modest rises in atmospheric carbon dioxide. Right now, researchers have repeatedly confirmed that the present increasingly rapid rise is the highest in the last 800,000 years.

Now a team from the US and Norway report in the journal Geology that they have measured past atmospheric carbon levels in fossil plants to establish that present day carbon levels are higher currently than at any time in the last 23 million years.

This means that – unless there are drastic steps to contain global warming – the retreat will become increasingly more rapid, and the rate of glacial flow towards the sea ever faster.

Were all the ice in Antarctica to melt, sea levels would rise by about 60 metres, completely submerging many of the world’s great cities. – Climate News Network