Category Archives: Polar

Greenland’s icecap melt picks up speed

Recent melting of Greenland’s icecap has been more intense than ever. And all the signs are that it could get worse.

LONDON, 13 December, 2018 – Greenland’s icecap – the largest single store of frozen freshwater in the northern hemisphere – is melting faster than ever, according to two separate studies using two different approaches.

Surface meltwater started flowing over the surface and percolating through the ice at a greater rate in the mid-19th century and accelerated dramatically during the 20th and the first decades of the 21st century, according to a new study of ice cores taken more than 2,000 metres above sea level.

And a 25-year record of European Space Agency satellite data confirms the alarming picture: the elevation of the Greenland ice sheet was changing in the mid-1990s, and the pace of thinning stepped up after 2003. Greenland’s bedrock carries enough ice to raise global sea levels by around seven metres.

“Melting of the Greenland Ice Sheet has gone into overdrive. As a result, Greenland melt is adding to sea level more than at any time in the last three and a half centuries, if not thousands of years,” said Luke Trusel, a glaciologist at Rowan University in the US.

“And increasing melt began around the same time as we started altering the atmosphere in the mid 1800s.”

“The melting and sea level rise we’ve observed will already be dwarfed by what may be expected in the future”

His co-author Sarah Das of the Woods Hole Oceanographic Institution said: “From a historical perspective, today’s melt rates are off the charts, and this study provides the evidence.”

Snow falls on the great icecaps of the two hemispheres, freezes, melts a little in the summer and freezes again, so that – like the rings of a tree – the accumulated precipitation tells a story of successive years of climate change. The two researchers and their colleagues report in Nature that ice cores taken from the icecap between 2003 and 2015 contained enough information for them to assess annual melting rates over several centuries.

They found a clear pattern of more intense melting nearer the present, and over the last 20 years the intensity increased by between 250% and 575%, compared to the 18th century. In the last century the entire planet has warmed by around 1°C as greenhouse gas levels in the atmosphere have risen, in response to ever greater use of fossil fuels.

The message for the future is ominous. “Rather than increasing steadily as climate warms, Greenland will melt increasingly more and more for every degree of warming,” said Dr Trusel. “The melting and sea level rise we’ve observed will already be dwarfed by what may be expected in the future as climate continues to warm.”

Greenland has served for decades as a climate laboratory: change almost imperceptible in lower latitudes can be measured almost on a yearly basis in the high fastnesses of the island, and the Nature study is only the latest twist in a story that is already alarming.

Dangers identified

Scientists long ago took the measure of change on the ice cap, in the glaciers and at the boundary with the Atlantic, and identified the dangers of accelerated warming in the Arctic.

They monitored unexpected increases in the flow of the island’s biggest glaciers, monitored the way the island’s bedrock rose in response to an increased loss of ice, and even identified those reaches of ice that had passed the point of no return.

The Nature scientists backed up their on-the-ground observations with measurements made by satellites. And in an entirely separate study, European researchers report in the journal Earth and Planetary Science Letters that, according to their readings too, the elevation of the icecap had begun to change in ways that enabled them to measure ice loss with the decades, and a recent speed-up.

“A pattern of thinning appears to dominate a large fraction of the ice sheet margins at the beginning of the millennium, with individual outlet glaciers exhibiting large thinning rates,” said Louise Sandberg Sørenson, of the Danish National Space Institute, who led the research.

“Over the full 25-year period, the general picture shows much larger volume losses are experienced in west, northwest and southeast basins of Greenland, compared to the more steady-state situations in the colder north.” – Climate News Network

Recent melting of Greenland’s icecap has been more intense than ever. And all the signs are that it could get worse.

LONDON, 13 December, 2018 – Greenland’s icecap – the largest single store of frozen freshwater in the northern hemisphere – is melting faster than ever, according to two separate studies using two different approaches.

Surface meltwater started flowing over the surface and percolating through the ice at a greater rate in the mid-19th century and accelerated dramatically during the 20th and the first decades of the 21st century, according to a new study of ice cores taken more than 2,000 metres above sea level.

And a 25-year record of European Space Agency satellite data confirms the alarming picture: the elevation of the Greenland ice sheet was changing in the mid-1990s, and the pace of thinning stepped up after 2003. Greenland’s bedrock carries enough ice to raise global sea levels by around seven metres.

“Melting of the Greenland Ice Sheet has gone into overdrive. As a result, Greenland melt is adding to sea level more than at any time in the last three and a half centuries, if not thousands of years,” said Luke Trusel, a glaciologist at Rowan University in the US.

“And increasing melt began around the same time as we started altering the atmosphere in the mid 1800s.”

“The melting and sea level rise we’ve observed will already be dwarfed by what may be expected in the future”

His co-author Sarah Das of the Woods Hole Oceanographic Institution said: “From a historical perspective, today’s melt rates are off the charts, and this study provides the evidence.”

Snow falls on the great icecaps of the two hemispheres, freezes, melts a little in the summer and freezes again, so that – like the rings of a tree – the accumulated precipitation tells a story of successive years of climate change. The two researchers and their colleagues report in Nature that ice cores taken from the icecap between 2003 and 2015 contained enough information for them to assess annual melting rates over several centuries.

They found a clear pattern of more intense melting nearer the present, and over the last 20 years the intensity increased by between 250% and 575%, compared to the 18th century. In the last century the entire planet has warmed by around 1°C as greenhouse gas levels in the atmosphere have risen, in response to ever greater use of fossil fuels.

The message for the future is ominous. “Rather than increasing steadily as climate warms, Greenland will melt increasingly more and more for every degree of warming,” said Dr Trusel. “The melting and sea level rise we’ve observed will already be dwarfed by what may be expected in the future as climate continues to warm.”

Greenland has served for decades as a climate laboratory: change almost imperceptible in lower latitudes can be measured almost on a yearly basis in the high fastnesses of the island, and the Nature study is only the latest twist in a story that is already alarming.

Dangers identified

Scientists long ago took the measure of change on the ice cap, in the glaciers and at the boundary with the Atlantic, and identified the dangers of accelerated warming in the Arctic.

They monitored unexpected increases in the flow of the island’s biggest glaciers, monitored the way the island’s bedrock rose in response to an increased loss of ice, and even identified those reaches of ice that had passed the point of no return.

The Nature scientists backed up their on-the-ground observations with measurements made by satellites. And in an entirely separate study, European researchers report in the journal Earth and Planetary Science Letters that, according to their readings too, the elevation of the icecap had begun to change in ways that enabled them to measure ice loss with the decades, and a recent speed-up.

“A pattern of thinning appears to dominate a large fraction of the ice sheet margins at the beginning of the millennium, with individual outlet glaciers exhibiting large thinning rates,” said Louise Sandberg Sørenson, of the Danish National Space Institute, who led the research.

“Over the full 25-year period, the general picture shows much larger volume losses are experienced in west, northwest and southeast basins of Greenland, compared to the more steady-state situations in the colder north.” – Climate News Network

Arctic shorebirds face rising predation risk

Rapid warning means rapid change in the north. That’s bad news for the hardy Arctic shorebirds and delicate plants that once found safety there.

LONDON, 13 November, 2018 – Vulnerable baby birds are no longer safe in their nests. New research shows that nest predation – the theft of the eggs of migrant Arctic shorebirds such as plovers and sandpipers in the high latitudes of the northern hemisphere – has risen threefold in the last 70 years.

A second study suggests that the very thing that encourages Arctic plant growth – the rapid warming of the north polar regions – also means a loss of vital snow cover for the delicate plants in the high mountains that depend on snow for winter insulation. This is bad news for the snow buttercup, mountain sorrel and mossplant.

British, Czech, Russian and |Hungarian researchers report in the journal Science that they compared rates of nest robbery over two timespans, from 1944 to 1999 and from 2000 to 2015, around the world.

Altogether the study covered 38,191 nests in 237 populations of 111 species in 149 locations. Nest predation in the tropics was always higher – perhaps because there are more predators – and tropical bird species tend to counter offspring loss by living longer to generate more.

But, the researchers found, nest predation in temperate Europe, Asia and North America had doubled. And in the Arctic, nestling loss by shorebirds had risen threefold.

“The future changes in northern species populations may be abrupt, giving rise to ecological surprises that are hard to predict”

In fact, certain species have always flown far north to breed because until the Arctic began to warm rapidly, as a consequence of ever higher levels of the greenhouse gas carbon dioxide in the atmosphere, the Arctic provided a relatively safe space for ground-nesting birds.

The reason for ever greater nest losses? This has yet to be established. But the guess is that as change comes to the plants and animal life of the Arctic, either predator species have changed, or the loss of familiar prey has forced a change of diet on hunters.

Because snow cover in the high Arctic has changed the lemming population has crashed, and the carnivores that hunted lemmings may now have turned to birds’ nests.

“These findings are alarming. The Earth is a fragile planet with complex ecosystems, thus changes in predator-prey relationships can lead to cascading effects through the food web with detrimental consequences for many organisms thousands of kilometres away,” said Tamás Székely, a biologist at the University of Bath, UK, with research posts at Hungarian and Chinese universities.

Final blow

“Migration of shorebirds from the Arctic to the tropics is now one of the largest movements of biomass in the world. But with increased nest predation, the babies are no longer making the journeys with their parents. This could be the last nail in the coffin for critically-endangered species such as the spoon-billed sandpiper.”

And Vojtěch Kubelka, of Charles University in Prague, who led the research, said the Arctic was no longer a safe harbour for breeding birds. “On the contrary, the Arctic now represents an extensive ecological trap.”

Rapid warming of the north polar regions also means a more rapid invasion of plants from further south and a change in plant response.

Finnish scientists report in the journal Nature Climate Change that changes in snow cover on the high ground may be an even greater danger to Arctic biodiversity than rising temperatures.

Snow cover crucial

They looked at satellite data and computer-based models of probable change as humans burn ever more fossil fuels to drive global warming and climate change, and applied the results to 273 flowering plants, mosses and lichens at 1200 locations in the mountains of northern Scandinavia.

Snow that now lingers until late spring provides vital protection for fragile growths and prevents hardier southern species from colonising the same habitat. In brief, it limits the competition.

The great unknown remains snowfall: while climate scientists can be sure of likely future temperatures at any latitude, it is much harder to predict changes in precipitation. But if the snow cover is reduced, then local extinction rates could accelerate. Plants that once maintained a precarious hold in extreme conditions could vanish with the snows.

“Our findings show that the future changes in northern species populations may be abrupt, giving rise to ecological surprises that are hard to predict, such as fast eradications of populations in some places and the invasion of flexible species into new places”, said Risto Heikkinen from the Finnish Environment Institute. – Climate News Network

Rapid warning means rapid change in the north. That’s bad news for the hardy Arctic shorebirds and delicate plants that once found safety there.

LONDON, 13 November, 2018 – Vulnerable baby birds are no longer safe in their nests. New research shows that nest predation – the theft of the eggs of migrant Arctic shorebirds such as plovers and sandpipers in the high latitudes of the northern hemisphere – has risen threefold in the last 70 years.

A second study suggests that the very thing that encourages Arctic plant growth – the rapid warming of the north polar regions – also means a loss of vital snow cover for the delicate plants in the high mountains that depend on snow for winter insulation. This is bad news for the snow buttercup, mountain sorrel and mossplant.

British, Czech, Russian and |Hungarian researchers report in the journal Science that they compared rates of nest robbery over two timespans, from 1944 to 1999 and from 2000 to 2015, around the world.

Altogether the study covered 38,191 nests in 237 populations of 111 species in 149 locations. Nest predation in the tropics was always higher – perhaps because there are more predators – and tropical bird species tend to counter offspring loss by living longer to generate more.

But, the researchers found, nest predation in temperate Europe, Asia and North America had doubled. And in the Arctic, nestling loss by shorebirds had risen threefold.

“The future changes in northern species populations may be abrupt, giving rise to ecological surprises that are hard to predict”

In fact, certain species have always flown far north to breed because until the Arctic began to warm rapidly, as a consequence of ever higher levels of the greenhouse gas carbon dioxide in the atmosphere, the Arctic provided a relatively safe space for ground-nesting birds.

The reason for ever greater nest losses? This has yet to be established. But the guess is that as change comes to the plants and animal life of the Arctic, either predator species have changed, or the loss of familiar prey has forced a change of diet on hunters.

Because snow cover in the high Arctic has changed the lemming population has crashed, and the carnivores that hunted lemmings may now have turned to birds’ nests.

“These findings are alarming. The Earth is a fragile planet with complex ecosystems, thus changes in predator-prey relationships can lead to cascading effects through the food web with detrimental consequences for many organisms thousands of kilometres away,” said Tamás Székely, a biologist at the University of Bath, UK, with research posts at Hungarian and Chinese universities.

Final blow

“Migration of shorebirds from the Arctic to the tropics is now one of the largest movements of biomass in the world. But with increased nest predation, the babies are no longer making the journeys with their parents. This could be the last nail in the coffin for critically-endangered species such as the spoon-billed sandpiper.”

And Vojtěch Kubelka, of Charles University in Prague, who led the research, said the Arctic was no longer a safe harbour for breeding birds. “On the contrary, the Arctic now represents an extensive ecological trap.”

Rapid warming of the north polar regions also means a more rapid invasion of plants from further south and a change in plant response.

Finnish scientists report in the journal Nature Climate Change that changes in snow cover on the high ground may be an even greater danger to Arctic biodiversity than rising temperatures.

Snow cover crucial

They looked at satellite data and computer-based models of probable change as humans burn ever more fossil fuels to drive global warming and climate change, and applied the results to 273 flowering plants, mosses and lichens at 1200 locations in the mountains of northern Scandinavia.

Snow that now lingers until late spring provides vital protection for fragile growths and prevents hardier southern species from colonising the same habitat. In brief, it limits the competition.

The great unknown remains snowfall: while climate scientists can be sure of likely future temperatures at any latitude, it is much harder to predict changes in precipitation. But if the snow cover is reduced, then local extinction rates could accelerate. Plants that once maintained a precarious hold in extreme conditions could vanish with the snows.

“Our findings show that the future changes in northern species populations may be abrupt, giving rise to ecological surprises that are hard to predict, such as fast eradications of populations in some places and the invasion of flexible species into new places”, said Risto Heikkinen from the Finnish Environment Institute. – Climate News Network

High Arctic plant spurts raise climate concerns

Arctic

Plants are getting taller in the Arctic high latitudes as warmer, moister soil prompts growth that could increase the release of greenhouse gases.

LONDON, 11 October, 2018 – The Arctic is becoming greener, warmer and leafier as small plants that once hugged the ground to trap snow and insulate their roots in the permafrost have started to gain in stature.

In the high latitudes, plants have begun to respond to climate change and warmer, moister soils by reaching for the sky.

It is estimated that, by 2100, the northernmost vegetation could have grown by up to 60% taller.

European scientists, backed by an international team of more than 120 biologists, report in Nature journal  that tundra plants are gaining in height, and that species from further south are advancing towards the Arctic Circle.

Close survey of growth

Their conclusion is based on more than 56,000 observations of tundra vegetation and a close survey of growth at 117 sites around the high latitudes in Alaska, Canada, Iceland, Scandinavia and Siberia.

“The increase in height we saw was not just in a few sites but nearly everywhere,” says Dr Anne Bjorkman, a researcher at Germany’s Senckenberg Biodiversity and Climate Research Centre. “If taller plants continue to spread at the current rate, the plant community height could increase by 20% to 60% by the end of the century.”

“Precipitation is likely to increase in the Arctic region, but that is just one factor that
affects soil moisture levels”

Her research colleague, Isla Myers-Smith, of the University of Edinburgh’s School of Geosciences, says: “While most climate change models have focused on increasing temperatures, our research has shown that soil moisture can play a much greater role in changing plant traits than we previously thought.

“We need to understand more about soil moisture in the Arctic. Precipitation is likely to increase in the Arctic region, but that is just one factor that affects soil moisture levels.”

The Arctic is one of the fastest-warming places on Earth. Sea ice has been in dramatic retreat and other research teams have repeatedly observed dramatic changes in the plants and animals that cling to life in the hemisphere’s harshest climate.

Ground reflectivity

What happens to tundra vegetation matters as a vast community of birds, insects and mammals survives on the annual growth in the brief northern summer.

Plants both respond to climate change and play a part in that change. They affect the reflectivity of the ground surface, and warm the soil in ways that could release ever more greenhouse gases.

Half of the planet’s stored carbon could be trapped in the permafrost, and any escapes could only accelerate global warming.

“This is the first time that a biome-scale study has been carried out to get to the root of the critical role that plants play in this rapidly-warming part of the planet,” Dr Myers-Smith says.

And Dr Bjorkman warns: “Shorter plants trap more snow, which insulates the underlying soil and prevents it from freezing as quickly in winter. An increase in taller plants could speed up the thawing of this frozen carbon bank, and lead to an increase in the release of greenhouse gases.” – Climate News Network

Plants are getting taller in the Arctic high latitudes as warmer, moister soil prompts growth that could increase the release of greenhouse gases.

LONDON, 11 October, 2018 – The Arctic is becoming greener, warmer and leafier as small plants that once hugged the ground to trap snow and insulate their roots in the permafrost have started to gain in stature.

In the high latitudes, plants have begun to respond to climate change and warmer, moister soils by reaching for the sky.

It is estimated that, by 2100, the northernmost vegetation could have grown by up to 60% taller.

European scientists, backed by an international team of more than 120 biologists, report in Nature journal  that tundra plants are gaining in height, and that species from further south are advancing towards the Arctic Circle.

Close survey of growth

Their conclusion is based on more than 56,000 observations of tundra vegetation and a close survey of growth at 117 sites around the high latitudes in Alaska, Canada, Iceland, Scandinavia and Siberia.

“The increase in height we saw was not just in a few sites but nearly everywhere,” says Dr Anne Bjorkman, a researcher at Germany’s Senckenberg Biodiversity and Climate Research Centre. “If taller plants continue to spread at the current rate, the plant community height could increase by 20% to 60% by the end of the century.”

“Precipitation is likely to increase in the Arctic region, but that is just one factor that
affects soil moisture levels”

Her research colleague, Isla Myers-Smith, of the University of Edinburgh’s School of Geosciences, says: “While most climate change models have focused on increasing temperatures, our research has shown that soil moisture can play a much greater role in changing plant traits than we previously thought.

“We need to understand more about soil moisture in the Arctic. Precipitation is likely to increase in the Arctic region, but that is just one factor that affects soil moisture levels.”

The Arctic is one of the fastest-warming places on Earth. Sea ice has been in dramatic retreat and other research teams have repeatedly observed dramatic changes in the plants and animals that cling to life in the hemisphere’s harshest climate.

Ground reflectivity

What happens to tundra vegetation matters as a vast community of birds, insects and mammals survives on the annual growth in the brief northern summer.

Plants both respond to climate change and play a part in that change. They affect the reflectivity of the ground surface, and warm the soil in ways that could release ever more greenhouse gases.

Half of the planet’s stored carbon could be trapped in the permafrost, and any escapes could only accelerate global warming.

“This is the first time that a biome-scale study has been carried out to get to the root of the critical role that plants play in this rapidly-warming part of the planet,” Dr Myers-Smith says.

And Dr Bjorkman warns: “Shorter plants trap more snow, which insulates the underlying soil and prevents it from freezing as quickly in winter. An increase in taller plants could speed up the thawing of this frozen carbon bank, and lead to an increase in the release of greenhouse gases.” – Climate News Network

Underwater walls might avert sea level rise

Could a vast underwater wall in front of an unstable glacier prevent dangerous sea level rise? Or should everyone just move further inland?

LONDON, 10 October, 2018 – Two climate scientists believe they have a long-term solution to dangerous sea level rise by targeting the most vulnerable glaciers, especially those that could trigger a massive collapse of the ice sheets behind them.

A submarine wall big enough and wide enough could halt the flow of increasingly warm ocean water below the front of each glacier. The combination of warmer air temperatures and warmer waters that accompany human-triggered climate change is dangerous: it could for instance accelerate the already alarming retreat of the Thwaites Glacier in West Antarctica, which alone shores up enough ice to raise global sea levels by up to 3 metres.

The scientists don’t propose an immediate start. But they do want to explore ways of halting sea level rise driven by global warming that could soon be costing the world $50 trillion a year in economic losses, that could submerge small island states and turn 1 million people a year into climate migrants.

“We are not advocating that glacial geoengineering be attempted any time soon”, they warn in the journal The Cryosphere.

Their simplest option – a series of pillars to shore up a targeted glacier and keep it “grounded” – would require engineering comparable in scale to the excavation of the Suez canal, would be undertaken in the world’s harshest environment, and would have just a one in three chance of success.

“In the long run we need plans to deal with the committed climate changes that are already in the pipeline, one of which may be an ice sheet collapse”

The researchers – John Moore, of Beijing Normal University in China, who also holds a post at the University of Lapland in Finland, and Michael Wolovick, of Princeton University in the US – have made this case before: they and others argued in March in Nature for what they call “managed collapse.”

In the latest study, they look at the challenge in greater detail. And they warn that even if targeted geoengineering of individual glaciers worked, it would only do so if humans stopped tipping ever more greenhouse gases into the atmosphere to fuel yet more global warming.

Nor do they argue that a submarine curtain wall to halt warming water across the front of the Thwaites glacier – up to 100 kms wide – is currently feasible. “But in the long run we need plans to deal with the committed climate changes that are already in the pipeline, one of which may be an ice sheet collapse.”

And one of these is the Thwaites Glacier in Antarctica: another is the Jakobshaven Isbrae in Greenland. Both could be cases of what the scientists call marine ice sheet instability: as a glacier retreats from its grounding line, the ice lifts off the bedrock and begins to float.

If the bedrock slopes down towards the centre of the ice sheet, and warmer ocean currents wash beneath it, then the ice starts to stretch and thin, and retreat further. At some point, it would become much easier for thawing ice to flow into the sea, and start what could become a runaway collapse. Engineers could devise a way of slowing or halting the process.

Huge impact

The scientists argue that even a rise of 0.6m to 1.2 metres by 2100 could cause up to $50 trillion in economic damage, and the resultant flooding could force up to 200 million to 500 million people out of their homes at least for a few days or weeks: around a million or so every year would never go back.

Climate scientists have been arguing about geoengineering solutions – the so-called technofix – to climate change for more than a decade. Global answers, such as blocking sunlight with stratospheric soot and sulphate aerosols, or whitening the polar ice to make it more reflective, remain contentious.

But the Cryosphere proposals are much more limited, and the immediate dangers of sea level rise are not contested. Ice sheet collapse in Antarctica, for instance, could raise sea levels by more than 3 metres and even by as much as 19 metres over the next two or three centuries.

The researchers’ calculations suggest that in theory an engineering solution that blocked even 50% of the warm water getting under a glacier could offer a 70% chance of delaying or stopping ice sheet collapse.

Left behind

Countries already spend on coastal protection: their solution would require international co-operation at the highest political level, and intensive scientific research.

“Managing sea level rise at the source has the advantage of benefiting the entire world, while a strategy that relies only on local coastal protection is more of an every-nation-for-itself approach that may leave many poor countries behind,” they write.

“Perhaps, after careful consideration, we may conclude that glacial geoengineering is unworkable and the right answer is to invest heavily in coastal protection and retreat inland where that is not practical or economical.

“However, we owe it to the 400 million people who live within 5m of sea level to at least consider the alternatives.” – Climate News Network

Could a vast underwater wall in front of an unstable glacier prevent dangerous sea level rise? Or should everyone just move further inland?

LONDON, 10 October, 2018 – Two climate scientists believe they have a long-term solution to dangerous sea level rise by targeting the most vulnerable glaciers, especially those that could trigger a massive collapse of the ice sheets behind them.

A submarine wall big enough and wide enough could halt the flow of increasingly warm ocean water below the front of each glacier. The combination of warmer air temperatures and warmer waters that accompany human-triggered climate change is dangerous: it could for instance accelerate the already alarming retreat of the Thwaites Glacier in West Antarctica, which alone shores up enough ice to raise global sea levels by up to 3 metres.

The scientists don’t propose an immediate start. But they do want to explore ways of halting sea level rise driven by global warming that could soon be costing the world $50 trillion a year in economic losses, that could submerge small island states and turn 1 million people a year into climate migrants.

“We are not advocating that glacial geoengineering be attempted any time soon”, they warn in the journal The Cryosphere.

Their simplest option – a series of pillars to shore up a targeted glacier and keep it “grounded” – would require engineering comparable in scale to the excavation of the Suez canal, would be undertaken in the world’s harshest environment, and would have just a one in three chance of success.

“In the long run we need plans to deal with the committed climate changes that are already in the pipeline, one of which may be an ice sheet collapse”

The researchers – John Moore, of Beijing Normal University in China, who also holds a post at the University of Lapland in Finland, and Michael Wolovick, of Princeton University in the US – have made this case before: they and others argued in March in Nature for what they call “managed collapse.”

In the latest study, they look at the challenge in greater detail. And they warn that even if targeted geoengineering of individual glaciers worked, it would only do so if humans stopped tipping ever more greenhouse gases into the atmosphere to fuel yet more global warming.

Nor do they argue that a submarine curtain wall to halt warming water across the front of the Thwaites glacier – up to 100 kms wide – is currently feasible. “But in the long run we need plans to deal with the committed climate changes that are already in the pipeline, one of which may be an ice sheet collapse.”

And one of these is the Thwaites Glacier in Antarctica: another is the Jakobshaven Isbrae in Greenland. Both could be cases of what the scientists call marine ice sheet instability: as a glacier retreats from its grounding line, the ice lifts off the bedrock and begins to float.

If the bedrock slopes down towards the centre of the ice sheet, and warmer ocean currents wash beneath it, then the ice starts to stretch and thin, and retreat further. At some point, it would become much easier for thawing ice to flow into the sea, and start what could become a runaway collapse. Engineers could devise a way of slowing or halting the process.

Huge impact

The scientists argue that even a rise of 0.6m to 1.2 metres by 2100 could cause up to $50 trillion in economic damage, and the resultant flooding could force up to 200 million to 500 million people out of their homes at least for a few days or weeks: around a million or so every year would never go back.

Climate scientists have been arguing about geoengineering solutions – the so-called technofix – to climate change for more than a decade. Global answers, such as blocking sunlight with stratospheric soot and sulphate aerosols, or whitening the polar ice to make it more reflective, remain contentious.

But the Cryosphere proposals are much more limited, and the immediate dangers of sea level rise are not contested. Ice sheet collapse in Antarctica, for instance, could raise sea levels by more than 3 metres and even by as much as 19 metres over the next two or three centuries.

The researchers’ calculations suggest that in theory an engineering solution that blocked even 50% of the warm water getting under a glacier could offer a 70% chance of delaying or stopping ice sheet collapse.

Left behind

Countries already spend on coastal protection: their solution would require international co-operation at the highest political level, and intensive scientific research.

“Managing sea level rise at the source has the advantage of benefiting the entire world, while a strategy that relies only on local coastal protection is more of an every-nation-for-itself approach that may leave many poor countries behind,” they write.

“Perhaps, after careful consideration, we may conclude that glacial geoengineering is unworkable and the right answer is to invest heavily in coastal protection and retreat inland where that is not practical or economical.

“However, we owe it to the 400 million people who live within 5m of sea level to at least consider the alternatives.” – Climate News Network

Frozen Arctic moves seawards in hectic melt

Once trapped in a Russian ice cap north of Siberia, the frozen Arctic is moving fast, racing in decades from metres to kilometres a year.

LONDON, 5 October, 2018 – Satellite images have revealed a dramatic change in Russia’s frozen Arctic. An ice cap that once crept almost imperceptibly across the barren rocks of October Revolution island, in the Kara Sea, is on the move.

All ice, even when permanently frozen to the bedrock, moves. From 1952 to 1985, the western edge of the Vavilov ice cap, 1,820 square kilometres in area and between 300 metres and 600 metres in thickness, shifted at about 12 metres a year. Between 1998 and 2011, it stepped up the pace to 75 metres a year. Between 2014 and 2015, the ice front had broken into tongues that moved at more than 1,000 metres a year.

And between 2015 and 2016 the leading edge had started racing into the Kara Sea at 5,000 metres a year. It is also thinning at the rate of a third of a metre a day, according to a new study in the journal Earth and Planetary Science Letters.

The high Arctic is the fastest-warming place on Earth, and researchers have for more than 30 years been measuring changes in the rate at which sea ice shrinks and Greenland glaciers flow.

Role as metaphor

“In a warming climate, glacier acceleration is becoming more and more common, but the rate of ice loss at Vavilov is extreme and unexpected,” said Michael Willis, a geologist at the University of California Boulder, who led the study by scientists from the US, UK and Russia.

Glaciers and icecaps such as Vavilov cover about 450,000 square kilometres of the planet’s surface and hold enough frozen water to raise global sea levels by 30 cms. They form on land in polar “deserts” in which the temperatures are below freezing and snow falls at no more than 25 cms a year.

In the Arctic summer the snow cover melts, and water trickles down through the ice; over the years, snowfall patterns shift and the ice cap shifts under gravitational tug. All glaciers flow, but so slowly that their pace has been incorporated into metaphor.

For the study authors, who used decades of satellite studies of the high Arctic to measure the change, the puzzle is one of geophysics: how could a fast-frozen mass of ice get to the stage where it can slide, as if lubricated, across a rocky surface above sea level?

“Glacier acceleration is becoming more and more common, but the rate of ice loss at Vavilov is extreme and unexpected”

“We’ve never seen anything like this before, this study has raised as many questions as it has answered,” said Dr Willis. “And we’re now working on modelling the whole situation to get a better handle on the physics involved.”

But for climate scientists concerned with the bigger picture, the study is another instance of potentially catastrophic climate change in the making. Once an ice cap starts to flow, the process is unlikely to stop.

And a second study in the same week from the other end of the globe shows that it doesn’t take much to start the ice flowing into the sea. It has confirmed that average global warming of no more than 2°C above historic levels, given long enough,  could melt much of the world’s largest ice sheet.

Planetary average temperatures have already risen by 1°C since the first industrial exploitation of coal, gas and oil only 200 years ago, and right now, although 195 nations vowed in Paris in 2015 to keep the rise to “well below” 2°C by 2100, the world seems headed for at least a 3°C rise later this century.

Future loss inevitable

British, Australian, New Zealand, Spanish and Japanese scientists report in Nature that they reconstructed the impact of change on the East Antarctic ice sheet during interglacials, those warm pauses during the last Ice Age.

For about 2,500 years, Antarctic air temperatures rose by about 2°C, the huge fastness of ice began to melt, and sea levels rose. The West Antarctic ice sheet, which has repeatedly shown signs of thawing, holds enough water to raise sea levels by up to 5 metres. The apparently stable East Antarctic sheet holds enough to lift global sea levels by 53 metres. During the interglacials of 400,000 years ago and 125,000 years ago, sea levels rose between 6 metres and 13 metres higher than they are today.

“What we have learned is that even modest warming of just two degrees, if sustained for a couple of thousand years, is enough to cause the East Antarctic ice sheet to retreat in some of its low-lying areas,” said David Wilson, of the UK’s Imperial College, who led the research.

“With current global temperatures already one degree higher than during pre-industrial times, future ice loss seems inevitable if we fail to reduce carbon emissions.” – Climate News Network

Once trapped in a Russian ice cap north of Siberia, the frozen Arctic is moving fast, racing in decades from metres to kilometres a year.

LONDON, 5 October, 2018 – Satellite images have revealed a dramatic change in Russia’s frozen Arctic. An ice cap that once crept almost imperceptibly across the barren rocks of October Revolution island, in the Kara Sea, is on the move.

All ice, even when permanently frozen to the bedrock, moves. From 1952 to 1985, the western edge of the Vavilov ice cap, 1,820 square kilometres in area and between 300 metres and 600 metres in thickness, shifted at about 12 metres a year. Between 1998 and 2011, it stepped up the pace to 75 metres a year. Between 2014 and 2015, the ice front had broken into tongues that moved at more than 1,000 metres a year.

And between 2015 and 2016 the leading edge had started racing into the Kara Sea at 5,000 metres a year. It is also thinning at the rate of a third of a metre a day, according to a new study in the journal Earth and Planetary Science Letters.

The high Arctic is the fastest-warming place on Earth, and researchers have for more than 30 years been measuring changes in the rate at which sea ice shrinks and Greenland glaciers flow.

Role as metaphor

“In a warming climate, glacier acceleration is becoming more and more common, but the rate of ice loss at Vavilov is extreme and unexpected,” said Michael Willis, a geologist at the University of California Boulder, who led the study by scientists from the US, UK and Russia.

Glaciers and icecaps such as Vavilov cover about 450,000 square kilometres of the planet’s surface and hold enough frozen water to raise global sea levels by 30 cms. They form on land in polar “deserts” in which the temperatures are below freezing and snow falls at no more than 25 cms a year.

In the Arctic summer the snow cover melts, and water trickles down through the ice; over the years, snowfall patterns shift and the ice cap shifts under gravitational tug. All glaciers flow, but so slowly that their pace has been incorporated into metaphor.

For the study authors, who used decades of satellite studies of the high Arctic to measure the change, the puzzle is one of geophysics: how could a fast-frozen mass of ice get to the stage where it can slide, as if lubricated, across a rocky surface above sea level?

“Glacier acceleration is becoming more and more common, but the rate of ice loss at Vavilov is extreme and unexpected”

“We’ve never seen anything like this before, this study has raised as many questions as it has answered,” said Dr Willis. “And we’re now working on modelling the whole situation to get a better handle on the physics involved.”

But for climate scientists concerned with the bigger picture, the study is another instance of potentially catastrophic climate change in the making. Once an ice cap starts to flow, the process is unlikely to stop.

And a second study in the same week from the other end of the globe shows that it doesn’t take much to start the ice flowing into the sea. It has confirmed that average global warming of no more than 2°C above historic levels, given long enough,  could melt much of the world’s largest ice sheet.

Planetary average temperatures have already risen by 1°C since the first industrial exploitation of coal, gas and oil only 200 years ago, and right now, although 195 nations vowed in Paris in 2015 to keep the rise to “well below” 2°C by 2100, the world seems headed for at least a 3°C rise later this century.

Future loss inevitable

British, Australian, New Zealand, Spanish and Japanese scientists report in Nature that they reconstructed the impact of change on the East Antarctic ice sheet during interglacials, those warm pauses during the last Ice Age.

For about 2,500 years, Antarctic air temperatures rose by about 2°C, the huge fastness of ice began to melt, and sea levels rose. The West Antarctic ice sheet, which has repeatedly shown signs of thawing, holds enough water to raise sea levels by up to 5 metres. The apparently stable East Antarctic sheet holds enough to lift global sea levels by 53 metres. During the interglacials of 400,000 years ago and 125,000 years ago, sea levels rose between 6 metres and 13 metres higher than they are today.

“What we have learned is that even modest warming of just two degrees, if sustained for a couple of thousand years, is enough to cause the East Antarctic ice sheet to retreat in some of its low-lying areas,” said David Wilson, of the UK’s Imperial College, who led the research.

“With current global temperatures already one degree higher than during pre-industrial times, future ice loss seems inevitable if we fail to reduce carbon emissions.” – Climate News Network

Arctic thaw imperils climate goals

Promises to slow climate change have yet to be implemented. And even if they are, they may not be enough, because of the Arctic thaw.

LONDON, 26 September, 2018 – Austrian researchers have bad news for those nations alarmed about climate change: the Arctic thaw means the chances that the world will exceed the global warming limit set by international agreement are high – and getting ever higher with every tiny shift in the planetary thermometer.

Warming in the Arctic is the fastest on the planet – and any warming will release ever more methane and other forms of stored carbon from the thawing permafrost.

Methane is a greenhouse gas far more potent than carbon dioxide. And as it seeps into the atmosphere, the chances that the world will overshoot its promise to contain planetary warming to “well below” 2°C increase.

This target was agreed by 195 nations at a summit in Paris in 2015. The promise implicit in this historic decision was that the world would by 2100 be no hotter than 1.5°C above historic levels.

Global average temperatures have already risen by about 1°C in the last century, thanks to unconstrained combustion of fossil fuels that deposit ancient stored carbon back into the atmosphere in the form of ever more carbon dioxide.

“Getting back to lower levels after an overshoot will be extremely difficult … we may never get back to safer levels of warming”

But, says an international team led by Thomas Gasser of the International Institute for Applied Systems Analysis in Austria, there are prodigious amounts of carbon stored in the world’s once permanently frozen soils. As these are released, the chances are that global warming will accelerate.

“Permafrost carbon release from previously frozen organic matter is caused by global warming, and will certainly diminish the budget of CO2 we can emit while staying below a certain level of global warming,” Dr Gasser said.

“It is also an irreversible process over the course of a few centuries, and may therefore be considered a ‘tipping’ element of the Earth’s carbon-climate system that puts the linear approximation of the emission budget framework to the test.”

The message behind the formal language of a paper in the journal Nature Geoscience is simple: the world has less time to act than the presidents and prime ministers who signed the Paris Declaration may think.

But this is no surprise. Right from the start, leading climate scientists were warning that the planet could already be much nearer its optimum target than anybody suspected.

Other researchers have repeatedly stressed the need for urgency, and the inadequacy of any of the prepared responses.

Feedback concern

Concern about the permafrost, too, is not new: polar researchers have been arguing for years that any thaw will increase the atmospheric carbon burden, which will in turn accelerate further warning, with potentially catastrophic consequences.

It is one thing to slow the rate of global warming by drastically reducing fossil fuel emissions and restoring the world’s forests so as to arrive at a limit; quite another thing to overshoot the limit and then try to reduce the planetary temperature, the latest study suggests. There is no simple correlation between burning coal or oil and the planetary temperatures that follow.

“Overshooting is a risky strategy and getting back to lower levels after an overshoot will be extremely difficult. However, since we are officially on an overshooting trajectory, we have to prepare ourselves for the possibility that we may never get back to safer levels of warming,” Dr Gasser said.

“Policymakers should understand that there is no elementary proportionality between cumulative CO2 emissions due to human activity and global temperature, as previously believed, and that overshooting may have serious consequences.” – Climate News Network


 

Promises to slow climate change have yet to be implemented. And even if they are, they may not be enough, because of the Arctic thaw.

LONDON, 26 September, 2018 – Austrian researchers have bad news for those nations alarmed about climate change: the Arctic thaw means the chances that the world will exceed the global warming limit set by international agreement are high – and getting ever higher with every tiny shift in the planetary thermometer.

Warming in the Arctic is the fastest on the planet – and any warming will release ever more methane and other forms of stored carbon from the thawing permafrost.

Methane is a greenhouse gas far more potent than carbon dioxide. And as it seeps into the atmosphere, the chances that the world will overshoot its promise to contain planetary warming to “well below” 2°C increase.

This target was agreed by 195 nations at a summit in Paris in 2015. The promise implicit in this historic decision was that the world would by 2100 be no hotter than 1.5°C above historic levels.

Global average temperatures have already risen by about 1°C in the last century, thanks to unconstrained combustion of fossil fuels that deposit ancient stored carbon back into the atmosphere in the form of ever more carbon dioxide.

“Getting back to lower levels after an overshoot will be extremely difficult … we may never get back to safer levels of warming”

But, says an international team led by Thomas Gasser of the International Institute for Applied Systems Analysis in Austria, there are prodigious amounts of carbon stored in the world’s once permanently frozen soils. As these are released, the chances are that global warming will accelerate.

“Permafrost carbon release from previously frozen organic matter is caused by global warming, and will certainly diminish the budget of CO2 we can emit while staying below a certain level of global warming,” Dr Gasser said.

“It is also an irreversible process over the course of a few centuries, and may therefore be considered a ‘tipping’ element of the Earth’s carbon-climate system that puts the linear approximation of the emission budget framework to the test.”

The message behind the formal language of a paper in the journal Nature Geoscience is simple: the world has less time to act than the presidents and prime ministers who signed the Paris Declaration may think.

But this is no surprise. Right from the start, leading climate scientists were warning that the planet could already be much nearer its optimum target than anybody suspected.

Other researchers have repeatedly stressed the need for urgency, and the inadequacy of any of the prepared responses.

Feedback concern

Concern about the permafrost, too, is not new: polar researchers have been arguing for years that any thaw will increase the atmospheric carbon burden, which will in turn accelerate further warning, with potentially catastrophic consequences.

It is one thing to slow the rate of global warming by drastically reducing fossil fuel emissions and restoring the world’s forests so as to arrive at a limit; quite another thing to overshoot the limit and then try to reduce the planetary temperature, the latest study suggests. There is no simple correlation between burning coal or oil and the planetary temperatures that follow.

“Overshooting is a risky strategy and getting back to lower levels after an overshoot will be extremely difficult. However, since we are officially on an overshooting trajectory, we have to prepare ourselves for the possibility that we may never get back to safer levels of warming,” Dr Gasser said.

“Policymakers should understand that there is no elementary proportionality between cumulative CO2 emissions due to human activity and global temperature, as previously believed, and that overshooting may have serious consequences.” – Climate News Network


 

Nature may explain North Atlantic circulation

Ocean circulation distributes the planet’s heat. If the North Atlantic circulation slows, is it because of global warming, or a natural cycle?

LONDON, 26 July, 2018 – The world can breathe again. Europe can relax: the glaciers will not return. The North Atlantic circulation may resume its former pace and the Gulf Stream slowdown could be coming to an end.

But that may not be entirely good news. Global warming could also be about to accelerate, according to new research into one of oceanography’s most enigmatic phenomena, the North Atlantic Meridional Overturning Circulation.

New studies of all the data so far by an ocean scientist and a mathematician say that what affects North Atlantic circulation may not be driven by man-made climate change. The ocean may be responding to a very long-term natural climate cycle.

At the heart of the puzzle is a simple fact. The flow of warm water from the tropical Atlantic right up to the coast of northern Norway has a dramatic impact on western Europe’s climate. This means that the United Kingdom, France, and other nations are conspicuously warmer than they might be if latitude was the only factor.

“We do not know if it is periodic, but based on the surface phenomena we think it’s very likely it is episodic”

A former UK chief scientist once calculated that the Gulf Stream contributed 27,000 times the warmth generated by all the UK’s power stations. But theorists argued that as the Arctic region warmed, the rate of flow could diminish, and paradoxically throw Europe into a new little Ice Age. A 2004 Hollywood disaster movie called The Day After Tomorrow followed this logic, with Britain frozen and glaciers cascading south into the US.

In fact, no such calamitous and sudden return of the intense and lethal cold could happen, but researchers have since then consistently observed a pattern of slowing in the North Atlantic circulation, linked such slowdowns to global warming
driven by profligate use of fossil fuels that enrich the levels of greenhouse gases in the atmosphere, and repeatedly warned that the consequences could be costly or even devastating.

But a new study of the data available exposes other possibilities. In the first place, climate scientists have direct measurements of the circulation strength only from 2004, and the decline measured since then has been 10 times more than anyone expected. Perhaps the slowdown could be just part of a regular, rhythmic cycle that happens independently of anything humans have done to trigger global warming, researchers say in the journal Nature.

“Many have focused on the fact that it’s declining very rapidly, and that if the trend continues it will go past a tipping point, bringing a catastrophe such as an ice age,” said Ka-Kit Tung, a mathematician at the University of Washington in the US.

Already over

“It turns out that none of that is going to happen in the near future. The fast response may instead be part of a natural cycle and there are signs that the decline is already ending.”

The Atlantic Meridional Overturning Circulation takes warm surface water northward. The dense salty water sinks into the Labrador and Nordic Seas and returns at depth all the way to the Southern Ocean, to rise again. The puzzle is what happens next.

As the current sinks in the far north, it carries heat away from the surface. But the same transport of heat causes the northern glaciers to recede, and melt, diluting the saline water and making it less likely to sink. So the circulation slows.

The reasoning that follows is that, in a slow phase, the North Atlantic becomes cooler, the ice melt slows, the fresh meltwater sources begin to dry up and the heavier, saltier water plunges more urgently, and the whole circulation speeds up again.

Disagreement

And if this happens in a natural cycle – and not all climate scientists and oceanographers will agree – it is one that lasts for many decades: 60 to 70 years. But oceanographers don’t have the more than 60 to 70 years of measurements needed to confirm this pattern.

“We have about one cycle of observations at depth, so we do not know if it is periodic, but based on the surface phenomena we think it’s very likely it is episodic,” said Professor Tung.

“The good news is that the indicators show that this slowdown of the Atlantic overturning circulation is ending, and so we shouldn’t be alarmed that this current will collapse any time soon.

“The bad news is that surface temperatures are likely to start rising more quickly in the coming decades.” – Climate News Network

Ocean circulation distributes the planet’s heat. If the North Atlantic circulation slows, is it because of global warming, or a natural cycle?

LONDON, 26 July, 2018 – The world can breathe again. Europe can relax: the glaciers will not return. The North Atlantic circulation may resume its former pace and the Gulf Stream slowdown could be coming to an end.

But that may not be entirely good news. Global warming could also be about to accelerate, according to new research into one of oceanography’s most enigmatic phenomena, the North Atlantic Meridional Overturning Circulation.

New studies of all the data so far by an ocean scientist and a mathematician say that what affects North Atlantic circulation may not be driven by man-made climate change. The ocean may be responding to a very long-term natural climate cycle.

At the heart of the puzzle is a simple fact. The flow of warm water from the tropical Atlantic right up to the coast of northern Norway has a dramatic impact on western Europe’s climate. This means that the United Kingdom, France, and other nations are conspicuously warmer than they might be if latitude was the only factor.

“We do not know if it is periodic, but based on the surface phenomena we think it’s very likely it is episodic”

A former UK chief scientist once calculated that the Gulf Stream contributed 27,000 times the warmth generated by all the UK’s power stations. But theorists argued that as the Arctic region warmed, the rate of flow could diminish, and paradoxically throw Europe into a new little Ice Age. A 2004 Hollywood disaster movie called The Day After Tomorrow followed this logic, with Britain frozen and glaciers cascading south into the US.

In fact, no such calamitous and sudden return of the intense and lethal cold could happen, but researchers have since then consistently observed a pattern of slowing in the North Atlantic circulation, linked such slowdowns to global warming
driven by profligate use of fossil fuels that enrich the levels of greenhouse gases in the atmosphere, and repeatedly warned that the consequences could be costly or even devastating.

But a new study of the data available exposes other possibilities. In the first place, climate scientists have direct measurements of the circulation strength only from 2004, and the decline measured since then has been 10 times more than anyone expected. Perhaps the slowdown could be just part of a regular, rhythmic cycle that happens independently of anything humans have done to trigger global warming, researchers say in the journal Nature.

“Many have focused on the fact that it’s declining very rapidly, and that if the trend continues it will go past a tipping point, bringing a catastrophe such as an ice age,” said Ka-Kit Tung, a mathematician at the University of Washington in the US.

Already over

“It turns out that none of that is going to happen in the near future. The fast response may instead be part of a natural cycle and there are signs that the decline is already ending.”

The Atlantic Meridional Overturning Circulation takes warm surface water northward. The dense salty water sinks into the Labrador and Nordic Seas and returns at depth all the way to the Southern Ocean, to rise again. The puzzle is what happens next.

As the current sinks in the far north, it carries heat away from the surface. But the same transport of heat causes the northern glaciers to recede, and melt, diluting the saline water and making it less likely to sink. So the circulation slows.

The reasoning that follows is that, in a slow phase, the North Atlantic becomes cooler, the ice melt slows, the fresh meltwater sources begin to dry up and the heavier, saltier water plunges more urgently, and the whole circulation speeds up again.

Disagreement

And if this happens in a natural cycle – and not all climate scientists and oceanographers will agree – it is one that lasts for many decades: 60 to 70 years. But oceanographers don’t have the more than 60 to 70 years of measurements needed to confirm this pattern.

“We have about one cycle of observations at depth, so we do not know if it is periodic, but based on the surface phenomena we think it’s very likely it is episodic,” said Professor Tung.

“The good news is that the indicators show that this slowdown of the Atlantic overturning circulation is ending, and so we shouldn’t be alarmed that this current will collapse any time soon.

“The bad news is that surface temperatures are likely to start rising more quickly in the coming decades.” – Climate News Network

Alien seaweed arrives in Antarctica

For more than a century, scientists believed that only humans could cross the hostile oceans to reach Antarctica. Some strands of alien seaweed tell another story.

LONDON, 19 July, 2018 – A foreign invader, a species of alien seaweed, has managed to cross the oceans to reach the frozen Antarctic shores. So scientists may have to give up a cherished belief: that Antarctica is inviolate.

For a century, researchers have assumed that the mix of ocean currents, distance and temperature have kept the Great White Continent shielded from invasion by Pacific or Atlantic flotsam.

But the discovery of strands of kelp on an Antarctic beach – seaweed that may have drifted for considerable periods and a distance of 20,000 kms before becoming stranded far from home – brings an end to that belief. And the discovery suggests that global warming could bring serious changes to Antarctic ecosystems.

“Our findings also indicate that plants and animals living on Antarctica could be more vulnerable to climate change than we suspected”

“This finding shows us that living plants and animals can reach Antarctica across the ocean, with temperate and sub-Antarctic marine species probably bombarding Antarctic coastlines all the time,” said Ceridwen Fraser, of the Australian National University.

“We always thought Antarctic plants and animals were distinct because they were isolated, but this research now suggests these differences are almost entirely due to environmental extremes, not isolation.”

Dr Fraser and her colleagues report in the journal Nature Climate Change that strands of southern bull kelp, Durvillaea antarctica, found by a Chilean scientist, must have floated 20,000 km from the Kerguelen Islands and South Georgia. The kelp was encrusted with barnacles, evidence of a long time adrift.

In fact, researchers believe, it may be evidence of the longest episode of “biological rafting” ever confirmed. The word raft is significant: such floating platforms could provide shelter and transport for other biological invaders.

Plastic next?

Until now, the assumption has been that the pattern of surface currents and westerly winds tends to drive drifting material northwards from Antarctica. The discovery suggests that if kelp can get there, so can floating driftwood, or plastic debris, or any other unwelcome visitor.

The researchers think large waves driven by Southern Ocean storms may have steered the kelp rafts over what had been considered a natural ocean barrier. Global warming has begun to change conditions in Antarctica, and the continent – considered the last great tract of terrain unmarked by human colonisation – could become increasingly vulnerable to change.

“This is an unequivocal demonstration that marine species from the north can reach Antarctica. To get there the kelp had to pass through barriers created by polar winds and currents that were, until now, thought to be impenetrable,” Dr Fraser said.

“Our findings also indicate that plants and animals living on Antarctica could be more vulnerable to climate change than we suspected.” – Climate News Network

For more than a century, scientists believed that only humans could cross the hostile oceans to reach Antarctica. Some strands of alien seaweed tell another story.

LONDON, 19 July, 2018 – A foreign invader, a species of alien seaweed, has managed to cross the oceans to reach the frozen Antarctic shores. So scientists may have to give up a cherished belief: that Antarctica is inviolate.

For a century, researchers have assumed that the mix of ocean currents, distance and temperature have kept the Great White Continent shielded from invasion by Pacific or Atlantic flotsam.

But the discovery of strands of kelp on an Antarctic beach – seaweed that may have drifted for considerable periods and a distance of 20,000 kms before becoming stranded far from home – brings an end to that belief. And the discovery suggests that global warming could bring serious changes to Antarctic ecosystems.

“Our findings also indicate that plants and animals living on Antarctica could be more vulnerable to climate change than we suspected”

“This finding shows us that living plants and animals can reach Antarctica across the ocean, with temperate and sub-Antarctic marine species probably bombarding Antarctic coastlines all the time,” said Ceridwen Fraser, of the Australian National University.

“We always thought Antarctic plants and animals were distinct because they were isolated, but this research now suggests these differences are almost entirely due to environmental extremes, not isolation.”

Dr Fraser and her colleagues report in the journal Nature Climate Change that strands of southern bull kelp, Durvillaea antarctica, found by a Chilean scientist, must have floated 20,000 km from the Kerguelen Islands and South Georgia. The kelp was encrusted with barnacles, evidence of a long time adrift.

In fact, researchers believe, it may be evidence of the longest episode of “biological rafting” ever confirmed. The word raft is significant: such floating platforms could provide shelter and transport for other biological invaders.

Plastic next?

Until now, the assumption has been that the pattern of surface currents and westerly winds tends to drive drifting material northwards from Antarctica. The discovery suggests that if kelp can get there, so can floating driftwood, or plastic debris, or any other unwelcome visitor.

The researchers think large waves driven by Southern Ocean storms may have steered the kelp rafts over what had been considered a natural ocean barrier. Global warming has begun to change conditions in Antarctica, and the continent – considered the last great tract of terrain unmarked by human colonisation – could become increasingly vulnerable to change.

“This is an unequivocal demonstration that marine species from the north can reach Antarctica. To get there the kelp had to pass through barriers created by polar winds and currents that were, until now, thought to be impenetrable,” Dr Fraser said.

“Our findings also indicate that plants and animals living on Antarctica could be more vulnerable to climate change than we suspected.” – Climate News Network

Arctic permafrost set for faster carbon leak

Researchers now know more about the intricate mechanisms of change in the thawing Arctic permafrost. And what they know is ominous.

LONDON, 18 July, 2018 – The Arctic permafrost – a frozen store of at least half the planet’s organic carbon – could be about to release more carbon in the form of greenhouse gases than it absorbs in the growing season.

A 42-year study of atmospheric carbon dioxide over the north slope of Alaska reveals that the “cycling time” – that is, the time a quantity of carbon is locked away in the frozen subsurface of the tundra regions – has been reduced by more than 13% over four decades.

This means that in response to global warming, the world’s greatest single store of ancient sunshine in the form of peat and other preserved vegetation is about to surrender yet more carbon dioxide and methane, and accelerate the process.

And a second study delivers better understanding of the mechanisms that will get to work as the permafrost thaws.

All decay from foliage and wood is achieved by soil microbes – and researchers have now taken more than 200 samples from a stretch of once-frozen bog and fen in northern Sweden to identify the genomic mix of fungi, bacteria and archaeo-bacteria ready and waiting to turn old vegetation back into atmospheric carbon.

“Large amounts of carbon sequestered in perennially frozen permafrost are becoming available for microbial degradation”

The first study is published in the journal Science Advances: Korean, US and Chinese scientists went to the data archives of the US National Oceanic and Atmospheric Administration to analyse the variations in carbon dioxide over Barrow, Alaska between 1974 and 2015.

Levels vary naturally from season to season as plants flower, bloom and die back in the brief polar summer. But over the 42-year span of the study, the scientists also found a pattern of change.

Respiration during the early cold season was, under the warming of the last four decades, beginning to outpace the take-up of carbon during the growing season, as the tundra dwindled, and the boreal woodlands began to march northwards.

And, they warn, by 2100 this potentially means an increase in atmospheric concentrations of greenhouse gases, an increase of from 50 billion tonnes of carbon to 200 billion tonnes.

More accurate prediction

Swedish and US researchers, led by Australian microbiologists, report in the journal Nature that they used new software to identify the DNA of 1,500 microbe samples, all new to science, and all little cogs in the complex machinery of decay, found in the thawed, partially thawed, and frozen first three metres of northern Swedish permafrost.

With luck and patience, the extra understanding of the biochemistry of change in the permafrost should lead to more accurate predictions of global warming.

“As global temperatures rise, large amounts of carbon sequestered in perennially frozen permafrost are becoming available for microbial degradation,” said Ben Woodcroft, of the Australian Centre for Ecogenomics at the University of Queensland, who led the research.

“Until now, accurate prediction of greenhouse gas emissions produced from thawing permafrost has been limited by our understanding of permafrost microbial communities and their carbon metabolisms.” – Climate News Network

Researchers now know more about the intricate mechanisms of change in the thawing Arctic permafrost. And what they know is ominous.

LONDON, 18 July, 2018 – The Arctic permafrost – a frozen store of at least half the planet’s organic carbon – could be about to release more carbon in the form of greenhouse gases than it absorbs in the growing season.

A 42-year study of atmospheric carbon dioxide over the north slope of Alaska reveals that the “cycling time” – that is, the time a quantity of carbon is locked away in the frozen subsurface of the tundra regions – has been reduced by more than 13% over four decades.

This means that in response to global warming, the world’s greatest single store of ancient sunshine in the form of peat and other preserved vegetation is about to surrender yet more carbon dioxide and methane, and accelerate the process.

And a second study delivers better understanding of the mechanisms that will get to work as the permafrost thaws.

All decay from foliage and wood is achieved by soil microbes – and researchers have now taken more than 200 samples from a stretch of once-frozen bog and fen in northern Sweden to identify the genomic mix of fungi, bacteria and archaeo-bacteria ready and waiting to turn old vegetation back into atmospheric carbon.

“Large amounts of carbon sequestered in perennially frozen permafrost are becoming available for microbial degradation”

The first study is published in the journal Science Advances: Korean, US and Chinese scientists went to the data archives of the US National Oceanic and Atmospheric Administration to analyse the variations in carbon dioxide over Barrow, Alaska between 1974 and 2015.

Levels vary naturally from season to season as plants flower, bloom and die back in the brief polar summer. But over the 42-year span of the study, the scientists also found a pattern of change.

Respiration during the early cold season was, under the warming of the last four decades, beginning to outpace the take-up of carbon during the growing season, as the tundra dwindled, and the boreal woodlands began to march northwards.

And, they warn, by 2100 this potentially means an increase in atmospheric concentrations of greenhouse gases, an increase of from 50 billion tonnes of carbon to 200 billion tonnes.

More accurate prediction

Swedish and US researchers, led by Australian microbiologists, report in the journal Nature that they used new software to identify the DNA of 1,500 microbe samples, all new to science, and all little cogs in the complex machinery of decay, found in the thawed, partially thawed, and frozen first three metres of northern Swedish permafrost.

With luck and patience, the extra understanding of the biochemistry of change in the permafrost should lead to more accurate predictions of global warming.

“As global temperatures rise, large amounts of carbon sequestered in perennially frozen permafrost are becoming available for microbial degradation,” said Ben Woodcroft, of the Australian Centre for Ecogenomics at the University of Queensland, who led the research.

“Until now, accurate prediction of greenhouse gas emissions produced from thawing permafrost has been limited by our understanding of permafrost microbial communities and their carbon metabolisms.” – Climate News Network

West Antarctica’s rocks’ rise may slow ice melt

The southern continent is changing fast. West Antarctica’s rocks are on the rise, something which could slow the rate of ice melt.

LONDON, 26 June, 2018 – Its ice sheet may be melting, but West Antarctica’s rocks are on the way up. In a dramatic demonstration of geology’s in-depth response to surface change, the submerged bedrock of that part of the southern continent is springing upwards at 41mm a year.

And as it does so, it may slow the rate of inexorable ice melt, as the western part of the continent sheds ice in response to global warming driven by profligate human combustion of fossil fuels.

But for the moment the finding is yet another surprising demonstration of what geophysicists call isostatic response: as mass is shifted from the surface of the continent – and that region of Antarctica has lost three trillion metric tons of ice in the last 25 years – the semi-liquid rocks of the Earth’s mantle, deep below the continental crust, flow below the lightening burden to liftthe crustal rocks higher.

This rate of rise is unexpectedly rapid. As more ice melts, the process is likely to accelerate. A century from now, that stretch of Antarctic peninsula could have risen by 8 metres.

“To keep global sea levels from rising more than a few feet this century and beyond, we must still limit greenhouse gas concentrations in the atmosphere”

“When the ice melts and gets thinner, the Earth readjusts, and rises immediately by a few millimetres, which depends on the ice lost,” said Valentina Barletta, of the Technical University of Denmark, who led the research.

“But the earth also acts a bit like a very hard memory-foam mattress. And it slowly keeps readjusting for several thousand years after the melting. In Scandinavia the bedrock is still rising about 10 millimetres per year because of the last ice age.”

Dr Barletta and US colleagues report in the journal Science that they gathered data from six global positioning satellite stations fixed to the exposed rock around a stretch of West Antarctica called the Amundsen Sea embayment.

They coupled that with seismic studies of the crustal bedrock and then ran an immense number of computer simulations to settle on the most likely explanation – that deep beneath that point of the southern continent, the Earth’s mantle was relatively hotter and more fluid, and could respond to changes in mass more swiftly.

Polar perplexities

At the heart of such research is the puzzle of southern polar dynamics: the complex interplay of ocean, atmosphere, precipitation and topography that keeps Antarctica the coldest, driest, iciest place on the planet: it may be technically a desert, but its continental crust carries almost two thirds of the world’s freshwater in frozen form. If it all melted, global sea levels would rise by 70 metres.

But such is the weight of ice that some parts of the continent are depressed below sea level. In West Antarctica the surrounding sea ice is so thick it is anchored to submerged bedrock, to provide a buffer that slows the rate of glacial flow from inland.

Right now, the West Antarctic Ice Sheet is spilling into the oceans the equivalent of a quarter of all the planet’s melting ice. If all of West Antarctica were to melt, global sea levels would rise by three metres.

And the fear is that, as the oceans and atmosphere warm in response to ever-rising levels of greenhouse gases in the atmosphere, winds and currents could loosen the great shelves of sea ice and send them floating north, at which point the glacial flow from the high ground of the continent to the sea would accelerate.

Stability explained

So the latest discovery helps explain the wider puzzle of why Antarctica’s ice has been relatively stable over long geological periods: as the ice melts, the bedrock rises, and the ice shelves are more likely to stay anchored to the mainland, at least at that particular “pinning point” above a hotter, more fluid mantle.

There is another factor at work: the gravitational pull of the ice itself, which raises sea level near the great mass of ancient polar ice. As the ice melts, the gravitational tug diminishes, and the sea levels subside.

“The lowering of the sea level, the rising of the pinning points and the decrease of the inland slope due to the uplift of the bedrock are all feedbacks that can stabilise the ice sheet,” said Terry Wilson, of Ohio State University, and one of the authors. “Under many realistic climate models, this should be enough to stabilise the ice sheet.”

But as planetary average temperatures rise, so does the hazard. Rick Aster, of Colorado State University, and another of the authors, warned: “To keep global sea levels from rising more than a few feet this century and beyond, we must still limit greenhouse gas concentrations in the atmosphere, which can only occur through international cooperation and innovation.” – Climate News Network

The southern continent is changing fast. West Antarctica’s rocks are on the rise, something which could slow the rate of ice melt.

LONDON, 26 June, 2018 – Its ice sheet may be melting, but West Antarctica’s rocks are on the way up. In a dramatic demonstration of geology’s in-depth response to surface change, the submerged bedrock of that part of the southern continent is springing upwards at 41mm a year.

And as it does so, it may slow the rate of inexorable ice melt, as the western part of the continent sheds ice in response to global warming driven by profligate human combustion of fossil fuels.

But for the moment the finding is yet another surprising demonstration of what geophysicists call isostatic response: as mass is shifted from the surface of the continent – and that region of Antarctica has lost three trillion metric tons of ice in the last 25 years – the semi-liquid rocks of the Earth’s mantle, deep below the continental crust, flow below the lightening burden to liftthe crustal rocks higher.

This rate of rise is unexpectedly rapid. As more ice melts, the process is likely to accelerate. A century from now, that stretch of Antarctic peninsula could have risen by 8 metres.

“To keep global sea levels from rising more than a few feet this century and beyond, we must still limit greenhouse gas concentrations in the atmosphere”

“When the ice melts and gets thinner, the Earth readjusts, and rises immediately by a few millimetres, which depends on the ice lost,” said Valentina Barletta, of the Technical University of Denmark, who led the research.

“But the earth also acts a bit like a very hard memory-foam mattress. And it slowly keeps readjusting for several thousand years after the melting. In Scandinavia the bedrock is still rising about 10 millimetres per year because of the last ice age.”

Dr Barletta and US colleagues report in the journal Science that they gathered data from six global positioning satellite stations fixed to the exposed rock around a stretch of West Antarctica called the Amundsen Sea embayment.

They coupled that with seismic studies of the crustal bedrock and then ran an immense number of computer simulations to settle on the most likely explanation – that deep beneath that point of the southern continent, the Earth’s mantle was relatively hotter and more fluid, and could respond to changes in mass more swiftly.

Polar perplexities

At the heart of such research is the puzzle of southern polar dynamics: the complex interplay of ocean, atmosphere, precipitation and topography that keeps Antarctica the coldest, driest, iciest place on the planet: it may be technically a desert, but its continental crust carries almost two thirds of the world’s freshwater in frozen form. If it all melted, global sea levels would rise by 70 metres.

But such is the weight of ice that some parts of the continent are depressed below sea level. In West Antarctica the surrounding sea ice is so thick it is anchored to submerged bedrock, to provide a buffer that slows the rate of glacial flow from inland.

Right now, the West Antarctic Ice Sheet is spilling into the oceans the equivalent of a quarter of all the planet’s melting ice. If all of West Antarctica were to melt, global sea levels would rise by three metres.

And the fear is that, as the oceans and atmosphere warm in response to ever-rising levels of greenhouse gases in the atmosphere, winds and currents could loosen the great shelves of sea ice and send them floating north, at which point the glacial flow from the high ground of the continent to the sea would accelerate.

Stability explained

So the latest discovery helps explain the wider puzzle of why Antarctica’s ice has been relatively stable over long geological periods: as the ice melts, the bedrock rises, and the ice shelves are more likely to stay anchored to the mainland, at least at that particular “pinning point” above a hotter, more fluid mantle.

There is another factor at work: the gravitational pull of the ice itself, which raises sea level near the great mass of ancient polar ice. As the ice melts, the gravitational tug diminishes, and the sea levels subside.

“The lowering of the sea level, the rising of the pinning points and the decrease of the inland slope due to the uplift of the bedrock are all feedbacks that can stabilise the ice sheet,” said Terry Wilson, of Ohio State University, and one of the authors. “Under many realistic climate models, this should be enough to stabilise the ice sheet.”

But as planetary average temperatures rise, so does the hazard. Rick Aster, of Colorado State University, and another of the authors, warned: “To keep global sea levels from rising more than a few feet this century and beyond, we must still limit greenhouse gas concentrations in the atmosphere, which can only occur through international cooperation and innovation.” – Climate News Network