Tag Archives: Glaciers

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

‘Eternal’ Swiss snow is melting faster

Scientists say stretches of “eternal” Swiss snow are melting faster than 20 years ago, with serious impacts for water supply and tourism.

LONDON, 21 September, 2018 – Parts of Europe’s alpine mountain chain are undergoing accelerating melting, as the “eternal” Swiss snow thaws ever faster, threatening both the skiing industry and the nation’s water supply.

Over a period of only 22 years, thousands of satellite images have provided irrefutable evidence that an extra 5,200 square kilometres of the country are now snow-free, compared with the decade 1995-2005.

Researchers from the University of Geneva and the United Nations Environment Programme have used data from four satellites which have been constantly photographing the Earth from space, compiling a record published by the Swiss Data Cube, which uses Earth observations to give a comprehensive  picture of the country’s snow cover and much else besides, including crops grown and forest cover.

It is the loss of snow cover that most disturbs the scientists. What they call “the eternal snow zone” still covered 27% of Swiss territory in the years from 1995 to 2005. Ten years later it had fallen to 23% – a loss of 2,100 sq km.

The eternal snow line marks the part of Switzerland above which the snow never used to melt in summer or winter. It is also defined as the area where any precipitation year-round has an 80-100% chance of being snow.

“We have stored the equivalent of 6,500 images covering 34 years, a feat that only an open data policy has made possible”

Other parts of the country, including the Swiss Plateau (about 30% of Switzerland’s area), the Rhone Valley, the Alps and the Jura mountains are also losing snow cover, adding up to the 5,200 sq km total. These areas, below the eternal snow line, have until now usually had lying snow in the winter.

The study was launched in 2016 on behalf of Switzerland’s Federal Office for the Environment. Knowing the extent of snow cover and its retreat is essential for developing public policies, the researchers say.

Beyond the economic issues linked to the threat to ski resorts – a familiar area of concern, heightened by this latest research, as many of them now face shortened seasons or outright abandonment – other problems such as flood risk and water supply are coming to the fore. Snow stores water in the winter for release in spring and summer, for both agriculture and drinking water.

Currently the increasing loss of ice from glaciers in the summer is making up for the missing snow, but previous work by scientists has shown that in the future, when glaciers disappear altogether, Switzerland could face a crisis.

The researchers have relied on the information available from the Data Cube to establish what is happening on the peaks. By superimposing repeated pictures of the same place over one another they have been able to observe small changes over time.

Wealth of data

The data was made freely available to researchers. One of them, Grégory Giuliani, said: “We have stored the equivalent of 6,500 images covering 34 years, a feat that only an open data policy has made possible. If we had had to acquire these images at market value, more than 6 million Swiss francs would have been invested.

“Knowing that each pixel of each image corresponds to the observation of a square of 10 by 10 meters, we have 110 billion observations today. It is inestimable wealth for the scientific community.”

Apart from snow cover scientists are worried about many other changes taking place in Switzerland because of climate change. They already know that glaciers are melting at record speeds and plants, birds and insects are heading further up the mountains, but there is much else to be gleaned from the new data base.

The Data Cube offers the possibility of studying vegetation, the evolution and rotation of agricultural areas, urbanisation and even water quality, as satellite images can be used to monitor three essential indicators in lakes and rivers: suspended particles, whether organic or mineral; chlorophyll content; and surface temperature.

The data are freely accessible, not only to scientists worldwide but also to the public, making it easy to compare data for specific areas of the territory at different times. “Our ambition is that everyone should be able to navigate freely in Swiss territory to understand its evolution”, said Grégory Giuliani. – Climate News Network

Scientists say stretches of “eternal” Swiss snow are melting faster than 20 years ago, with serious impacts for water supply and tourism.

LONDON, 21 September, 2018 – Parts of Europe’s alpine mountain chain are undergoing accelerating melting, as the “eternal” Swiss snow thaws ever faster, threatening both the skiing industry and the nation’s water supply.

Over a period of only 22 years, thousands of satellite images have provided irrefutable evidence that an extra 5,200 square kilometres of the country are now snow-free, compared with the decade 1995-2005.

Researchers from the University of Geneva and the United Nations Environment Programme have used data from four satellites which have been constantly photographing the Earth from space, compiling a record published by the Swiss Data Cube, which uses Earth observations to give a comprehensive  picture of the country’s snow cover and much else besides, including crops grown and forest cover.

It is the loss of snow cover that most disturbs the scientists. What they call “the eternal snow zone” still covered 27% of Swiss territory in the years from 1995 to 2005. Ten years later it had fallen to 23% – a loss of 2,100 sq km.

The eternal snow line marks the part of Switzerland above which the snow never used to melt in summer or winter. It is also defined as the area where any precipitation year-round has an 80-100% chance of being snow.

“We have stored the equivalent of 6,500 images covering 34 years, a feat that only an open data policy has made possible”

Other parts of the country, including the Swiss Plateau (about 30% of Switzerland’s area), the Rhone Valley, the Alps and the Jura mountains are also losing snow cover, adding up to the 5,200 sq km total. These areas, below the eternal snow line, have until now usually had lying snow in the winter.

The study was launched in 2016 on behalf of Switzerland’s Federal Office for the Environment. Knowing the extent of snow cover and its retreat is essential for developing public policies, the researchers say.

Beyond the economic issues linked to the threat to ski resorts – a familiar area of concern, heightened by this latest research, as many of them now face shortened seasons or outright abandonment – other problems such as flood risk and water supply are coming to the fore. Snow stores water in the winter for release in spring and summer, for both agriculture and drinking water.

Currently the increasing loss of ice from glaciers in the summer is making up for the missing snow, but previous work by scientists has shown that in the future, when glaciers disappear altogether, Switzerland could face a crisis.

The researchers have relied on the information available from the Data Cube to establish what is happening on the peaks. By superimposing repeated pictures of the same place over one another they have been able to observe small changes over time.

Wealth of data

The data was made freely available to researchers. One of them, Grégory Giuliani, said: “We have stored the equivalent of 6,500 images covering 34 years, a feat that only an open data policy has made possible. If we had had to acquire these images at market value, more than 6 million Swiss francs would have been invested.

“Knowing that each pixel of each image corresponds to the observation of a square of 10 by 10 meters, we have 110 billion observations today. It is inestimable wealth for the scientific community.”

Apart from snow cover scientists are worried about many other changes taking place in Switzerland because of climate change. They already know that glaciers are melting at record speeds and plants, birds and insects are heading further up the mountains, but there is much else to be gleaned from the new data base.

The Data Cube offers the possibility of studying vegetation, the evolution and rotation of agricultural areas, urbanisation and even water quality, as satellite images can be used to monitor three essential indicators in lakes and rivers: suspended particles, whether organic or mineral; chlorophyll content; and surface temperature.

The data are freely accessible, not only to scientists worldwide but also to the public, making it easy to compare data for specific areas of the territory at different times. “Our ambition is that everyone should be able to navigate freely in Swiss territory to understand its evolution”, said Grégory Giuliani. – 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

Antarctic buffer damage spurs ice break-up

The Antarctic buffer which has for millennia sheltered the continent’s huge inland ice sheet is being battered by seaborne wave action.

LONDON, 21 June, 2018 – The vast southern ice sheet, despite the Antarctic buffer which has protected it for so long, is now being threatened by ocean swells chipping away at the continent’s coastal edge, says a new study by US scientists published in the journal Nature.

For millennia the southern ice sheet has had this protective buffer of sea ice ringing its coastal shelves. But now the swells from the north are flexing them and can weaken their stabilising seaward edge. Regular inundation by summer meltwater as the edge breaks away can also contribute to rapid ice shelf disintegration.

Ice shelves, with their ring of sea ice, are thick plates of ice fed by tributary glaciers, floating seaward extensions of the massive grounded inland ice sheet. They slow the flow of ice from the sheet, so rapidly disintegrating shelves have implications for sea level rise.

“Sea ice here acts like the bumpers on a car – with the bumpers in place, the car can take a shock and not be damaged. Take them off, and every hit adds up,” said Ted Scambos, study co-author and senior research scientist at the National Snow and Ice Data Center at the University of Colorado Boulder.

Since 1995, three large ice shelves on the Antarctic Peninsula – Larsen A, Larsen B and Wilkins – have suddenly and dramatically disintegrated.
Occurring over a few weeks, or sometimes even only a few days, these break-ups mark an unprecedented departure from the more typical and natural recurring calving of larger icebergs every decade or so.

Trigger found

Until recently researchers had thought intense surface melting caused by a warming climate and ice fracturing were the sole culprits. But the new findings suggest that loss of sea ice and the calving of the seaward edge into narrow sliver-like icebergs are the trigger that sets off a rapid ice shelf disintegration.

“Our study breaks new ground in how it implicates sea ice change in sea level rise,” said Rob Massom, the study’s lead author and a senior research scientist at the Australian Antarctic Division and Antarctic Climate and Ecosystems Cooperative Research Centre.

“It introduces ocean wave-induced breakage of the outer margins of ice shelves following loss of a protective sea ice buffer as the straw that breaks the camel’s back.”

He and his colleagues analysed disintegrations on three ice shelves that had been stable for centuries or even millennia: Larsen A in 1995, Larsen B in 2002, and Wilkins in 2008 and 2009.

They confirmed that atmospheric warming led to increased meltwater on the surfaces of the shelves. Pooled meltwater then percolated downward through crevasses, setting off a hydrofracturing process that weakened the ice.

“Ocean wave-induced breakage of the outer margins of ice shelves following loss of a protective sea ice buffer [is] the straw that breaks the camel’s back”

Earlier studies have identified the central role that ice shelves play in making sea level rise more likely and the accelerating pace of Antarctic melting.

But, crucially, what the NSIDC analysis reveals is a previously little-recognised link to sea ice: all three disintegrations happened when there was little or no sea ice cover along the shelf edge. Without that protective buffer, the shelves became exposed to waves which flexed the already fractured ice.

“What we’ve found is that increased flexing of the outer parts of ice shelves by waves sets the ice up for destruction. Even though the movement is tiny, over time the shelf is weakened,” Scambos said.

In each case, ocean swells began affecting the ice shelf edge. As the shelves flexed, existing fractures along the seaward edge chipped off as long, thin, sliver-shaped icebergs, not the larger tabular icebergs more typical of Antarctic ice shelf calvings. The remaining ice shelf was then ripe for runaway collapse.

“Other ice shelves can survive for centuries if they don’t have surface meltwater – or if the water can run off easily,” Scambos said. “But with meltwater ponding and a legacy of weakening from sea ice loss, you can destroy a shelf in just a few weeks.”

Pressure off

Because ice shelves are already floating in the ocean and displacing their volume, like ice cubes in a glass of water, their disintegration does not contribute directly to sea level rise.

But they do provide a backpressure that moderates glacier flow speed. Once they’re gone, so is the backpressure, allowing the glaciers to flow more rapidly into the ocean and ultimately contribute to sea level rise.

“This represents an important pathway towards reducing current large uncertainty in predictions of the response of the Antarctic cryosphere to climate change and its contribution to sea level rise,” Dr Massom said.

The Antarctic ice sheet contains enough ice to raise sea level by approximately 57 metres (187 feet), about half the length of a soccer pitch. Worldwide, more than 100 million people currently live within 1m of mean sea level. – Climate News Network

The Antarctic buffer which has for millennia sheltered the continent’s huge inland ice sheet is being battered by seaborne wave action.

LONDON, 21 June, 2018 – The vast southern ice sheet, despite the Antarctic buffer which has protected it for so long, is now being threatened by ocean swells chipping away at the continent’s coastal edge, says a new study by US scientists published in the journal Nature.

For millennia the southern ice sheet has had this protective buffer of sea ice ringing its coastal shelves. But now the swells from the north are flexing them and can weaken their stabilising seaward edge. Regular inundation by summer meltwater as the edge breaks away can also contribute to rapid ice shelf disintegration.

Ice shelves, with their ring of sea ice, are thick plates of ice fed by tributary glaciers, floating seaward extensions of the massive grounded inland ice sheet. They slow the flow of ice from the sheet, so rapidly disintegrating shelves have implications for sea level rise.

“Sea ice here acts like the bumpers on a car – with the bumpers in place, the car can take a shock and not be damaged. Take them off, and every hit adds up,” said Ted Scambos, study co-author and senior research scientist at the National Snow and Ice Data Center at the University of Colorado Boulder.

Since 1995, three large ice shelves on the Antarctic Peninsula – Larsen A, Larsen B and Wilkins – have suddenly and dramatically disintegrated.
Occurring over a few weeks, or sometimes even only a few days, these break-ups mark an unprecedented departure from the more typical and natural recurring calving of larger icebergs every decade or so.

Trigger found

Until recently researchers had thought intense surface melting caused by a warming climate and ice fracturing were the sole culprits. But the new findings suggest that loss of sea ice and the calving of the seaward edge into narrow sliver-like icebergs are the trigger that sets off a rapid ice shelf disintegration.

“Our study breaks new ground in how it implicates sea ice change in sea level rise,” said Rob Massom, the study’s lead author and a senior research scientist at the Australian Antarctic Division and Antarctic Climate and Ecosystems Cooperative Research Centre.

“It introduces ocean wave-induced breakage of the outer margins of ice shelves following loss of a protective sea ice buffer as the straw that breaks the camel’s back.”

He and his colleagues analysed disintegrations on three ice shelves that had been stable for centuries or even millennia: Larsen A in 1995, Larsen B in 2002, and Wilkins in 2008 and 2009.

They confirmed that atmospheric warming led to increased meltwater on the surfaces of the shelves. Pooled meltwater then percolated downward through crevasses, setting off a hydrofracturing process that weakened the ice.

“Ocean wave-induced breakage of the outer margins of ice shelves following loss of a protective sea ice buffer [is] the straw that breaks the camel’s back”

Earlier studies have identified the central role that ice shelves play in making sea level rise more likely and the accelerating pace of Antarctic melting.

But, crucially, what the NSIDC analysis reveals is a previously little-recognised link to sea ice: all three disintegrations happened when there was little or no sea ice cover along the shelf edge. Without that protective buffer, the shelves became exposed to waves which flexed the already fractured ice.

“What we’ve found is that increased flexing of the outer parts of ice shelves by waves sets the ice up for destruction. Even though the movement is tiny, over time the shelf is weakened,” Scambos said.

In each case, ocean swells began affecting the ice shelf edge. As the shelves flexed, existing fractures along the seaward edge chipped off as long, thin, sliver-shaped icebergs, not the larger tabular icebergs more typical of Antarctic ice shelf calvings. The remaining ice shelf was then ripe for runaway collapse.

“Other ice shelves can survive for centuries if they don’t have surface meltwater – or if the water can run off easily,” Scambos said. “But with meltwater ponding and a legacy of weakening from sea ice loss, you can destroy a shelf in just a few weeks.”

Pressure off

Because ice shelves are already floating in the ocean and displacing their volume, like ice cubes in a glass of water, their disintegration does not contribute directly to sea level rise.

But they do provide a backpressure that moderates glacier flow speed. Once they’re gone, so is the backpressure, allowing the glaciers to flow more rapidly into the ocean and ultimately contribute to sea level rise.

“This represents an important pathway towards reducing current large uncertainty in predictions of the response of the Antarctic cryosphere to climate change and its contribution to sea level rise,” Dr Massom said.

The Antarctic ice sheet contains enough ice to raise sea level by approximately 57 metres (187 feet), about half the length of a soccer pitch. Worldwide, more than 100 million people currently live within 1m of mean sea level. – Climate News Network

UK and US scientists tackle Antarctic glacier

British and American scientists are joining forces to research the melting of an Antarctic glacier in what they are calling a race against time. 

CAMBRIDGE, UK, 30 April, 2018 – An international team of scientists is mounting an ambitious research programme to find how soon a vast Antarctic glacier may collapse, with implications for sea levels worldwide.

The Thwaites Glacier in West Antarctica could significantly affect global sea levels. It already drains an area roughly the size of Britain or the US state of Florida, accounting for around 4% of global sea-level rise, an amount that has doubled since the mid-1990s. Its collapse would destabilise other parts of the ice sheet.

If – or more likely when – Thwaites and its neighbour, the Pine Island glacier, ultimately lose all their ice, one estimate suggests that could raise global sea levels by about 3.4m, enough to affect every coastal city on Earth.

Fastest-moving

Satellites have shown for more than a decade that the Thwaites region is an area of massive change and rapid ice loss as the global climate warms in response to rising greenhouse gas emissions from humans’ profligate use of fossil fuels. The two glaciers are among the fastest-moving in the Antarctic.

One of the scientists involved in the research is David Vaughan, director of science at the Cambridge-based British Antarctic Survey (BAS). He says he and his colleagues are involved in “a race against time”.

Professor Vaughan told the Climate News Network: “Understanding sea level rise is the front line of climate change, and sea level rise doesn’t happen overnight. [What’s happening to Thwaites] is not an emergency this year, but I’m very glad we’re doing the research this decade, because we can’t wait too long.”

Understanding collapse

As part of a new £20 million (roughly US$27.5m) research collaboration, the UK Natural Environment Research Council and the US National Science Foundation are about to send a team of scientists to Antarctica to gather the data needed to understand when the collapse of the Thwaites glacier could begin – in centuries, or in the next few decades.

NERC and NSF are jointly funding eight large-scale projects that will bring together leading polar scientists in the International Thwaites Glacier Collaboration (ITGC), the largest joint project undertaken by the two nations in Antarctica for more than 70 years. The ITGC involves around 100 scientists from leading research institutes in both countries with researchers from South Korea, Germany, Sweden, New Zealand and Finland.

There are signs that the process of Thwaites’ collapse has already begun. Antarctica’s glaciers add to sea-level rise when they lose more ice to the ocean than they gain from snowfall. To fully understand the causes of changes in ice flow requires research on the ice itself, the nearby ocean, and the Antarctic climate.

“Sea level rise doesn’t happen overnight. [It’s] not an emergency this year, but I’m very glad we’re doing the research this decade, because we can’t wait too long”

The Collaboration will use drills that can make access holes 1,500 metres into the ice with jets of hot water, as well as other state-of-the-art techniques and equipment, such as autonomous submarines like the Autosub Long Range, the first of whose fleet is named Boaty McBoatface.

While NERC is funding the UK’s share of the project, it is being co-ordinated by BAS, whose total annual budget is around £50m. The agency co-ordinating the US share is the National Snow & Ice Data Center.

As well as the cost of the research itself, the physical problems of mounting a scientific campaign in one of the most remote places in Antarctica could cost as much again in logistical support. The nearest permanently occupied research station to the Thwaites glacier is more than 1,600km away, so even getting the scientists to where they need to be will be demanding.

Collaboration welcome

Researchers on the ice will rely on aircraft support from UK and US research stations, but oceanographers and geophysicists will approach the glacier from the sea in British and American research icebreakers.

The UK’s science minister, Sam Gyimah, said: “Rising sea levels are a globally important issue which cannot be tackled by one country alone. The Thwaites glacier already contributes to rising sea levels, and understanding its likely collapse in the coming century is vitally important.”

The five-year programme begins in October this year and continues to 2023. Its data will be archived and freely shared when it ends. – Climate News Network

British and American scientists are joining forces to research the melting of an Antarctic glacier in what they are calling a race against time. 

CAMBRIDGE, UK, 30 April, 2018 – An international team of scientists is mounting an ambitious research programme to find how soon a vast Antarctic glacier may collapse, with implications for sea levels worldwide.

The Thwaites Glacier in West Antarctica could significantly affect global sea levels. It already drains an area roughly the size of Britain or the US state of Florida, accounting for around 4% of global sea-level rise, an amount that has doubled since the mid-1990s. Its collapse would destabilise other parts of the ice sheet.

If – or more likely when – Thwaites and its neighbour, the Pine Island glacier, ultimately lose all their ice, one estimate suggests that could raise global sea levels by about 3.4m, enough to affect every coastal city on Earth.

Fastest-moving

Satellites have shown for more than a decade that the Thwaites region is an area of massive change and rapid ice loss as the global climate warms in response to rising greenhouse gas emissions from humans’ profligate use of fossil fuels. The two glaciers are among the fastest-moving in the Antarctic.

One of the scientists involved in the research is David Vaughan, director of science at the Cambridge-based British Antarctic Survey (BAS). He says he and his colleagues are involved in “a race against time”.

Professor Vaughan told the Climate News Network: “Understanding sea level rise is the front line of climate change, and sea level rise doesn’t happen overnight. [What’s happening to Thwaites] is not an emergency this year, but I’m very glad we’re doing the research this decade, because we can’t wait too long.”

Understanding collapse

As part of a new £20 million (roughly US$27.5m) research collaboration, the UK Natural Environment Research Council and the US National Science Foundation are about to send a team of scientists to Antarctica to gather the data needed to understand when the collapse of the Thwaites glacier could begin – in centuries, or in the next few decades.

NERC and NSF are jointly funding eight large-scale projects that will bring together leading polar scientists in the International Thwaites Glacier Collaboration (ITGC), the largest joint project undertaken by the two nations in Antarctica for more than 70 years. The ITGC involves around 100 scientists from leading research institutes in both countries with researchers from South Korea, Germany, Sweden, New Zealand and Finland.

There are signs that the process of Thwaites’ collapse has already begun. Antarctica’s glaciers add to sea-level rise when they lose more ice to the ocean than they gain from snowfall. To fully understand the causes of changes in ice flow requires research on the ice itself, the nearby ocean, and the Antarctic climate.

“Sea level rise doesn’t happen overnight. [It’s] not an emergency this year, but I’m very glad we’re doing the research this decade, because we can’t wait too long”

The Collaboration will use drills that can make access holes 1,500 metres into the ice with jets of hot water, as well as other state-of-the-art techniques and equipment, such as autonomous submarines like the Autosub Long Range, the first of whose fleet is named Boaty McBoatface.

While NERC is funding the UK’s share of the project, it is being co-ordinated by BAS, whose total annual budget is around £50m. The agency co-ordinating the US share is the National Snow & Ice Data Center.

As well as the cost of the research itself, the physical problems of mounting a scientific campaign in one of the most remote places in Antarctica could cost as much again in logistical support. The nearest permanently occupied research station to the Thwaites glacier is more than 1,600km away, so even getting the scientists to where they need to be will be demanding.

Collaboration welcome

Researchers on the ice will rely on aircraft support from UK and US research stations, but oceanographers and geophysicists will approach the glacier from the sea in British and American research icebreakers.

The UK’s science minister, Sam Gyimah, said: “Rising sea levels are a globally important issue which cannot be tackled by one country alone. The Thwaites glacier already contributes to rising sea levels, and understanding its likely collapse in the coming century is vitally important.”

The five-year programme begins in October this year and continues to 2023. Its data will be archived and freely shared when it ends. – Climate News Network

Polar ice is melting fast in north and south

In the high latitudes in both hemispheres, the polar ice is in retreat. Two studies support fears for the ice caps, north and south.

LONDON, 10 April, 2018 – New studies have confirmed, once again, the rapid melting of the polar ice in both hemispheres.

A British team has used satellite data to reveal that the retreat of the all-important grounding line of many Antarctic glaciers has accelerated to five times the historic level. And US scientists have confirmed that in Arctic waters the West Greenland ice sheet is now melting faster than at any time in the last 450 years.

Both studies deliver ominous evidence of the long-term consequences of climate change due to profligate human use of fossil fuels. The Greenland icecap holds enough water to raise global sea levels by seven metres. The West Antarctic ice sheet – where the latest study has identified most of the change – holds enough water to raise sea levels by up to five metres.

The UK measure of Antarctic ice retreat is important because it confirms on a wider scale what individual measurements of glacier retreat have already shown: that increasingly warm southern ocean waters are melting the ice at depth.

“This retreat has had a huge impact on inland glaciers, because releasing them from the sea bed removes friction, causing them to speed up and contribute to global sea level rise”

Depth in this study is critical: glaciers move slowly because the frozen rivers are “anchored” or grounded in bedrock as they flow off the continent, and then grounded again up to a kilometre deep off the continental shelf.

This applies a brake to the flow towards the open sea. The further from the coast the grounding line, the slower the glacier’s flow, the more stable the ice shelf, and the slower the consequent sea level rise.

Hannes Konrad of the University of Leeds in the UK and colleagues report in the journal Nature Geoscience that they used the European Space Agency’s satellite Cryosat-2 data to track the changes in the grounding line along 16,000 kilometres of southern polar coastline.

Around West Antarctica, more than a fifth of the ice sheet has retreated faster than the 25 metres or so a year that has been normal since the end of the last ice age. In some cases the retreat of the grounding line has been five times that rate. The retreat has been extreme in eight of the ice sheet’s 65 biggest glaciers.

Clear evidence

“Our study provides clear evidence that retreat is happening across the ice sheet due to ocean melting at its base, and not just at the few spots that have been mapped before now,” Dr Konrad said.

“This retreat has had a huge impact on inland glaciers, because releasing them from the sea bed removes friction, causing them to speed up and contribute to global sea level rise.”

Far to the north, ice is also melting. Erich Osterberg of Dartmouth College in the US and colleagues report in the journal Geophysical Research Letters that they collected seven ice cores from a remote zone in the West Greenland ice sheet where meltwater trickles down into the deeper snow and then freezes again: this “new” ice in the compacted snow provides scientists with a record of melting over time.

Longer record

Researchers have been watching the apparent acceleration of the summer melting of Greenland’s ice for decades: they have monitored ever faster rates of glacier flow and tried to identify direct influences on the surface of the ice sheet that might accelerate overall melting.

But direct observation of the northern hemisphere’s largest concentration of ice began only about five decades ago. The Dartmouth cores provide a total of almost five centuries of summer melt patterns.

“The ice core record ends about 450 years ago, so the modern melt rates in these cores are the highest of the whole record that we can see. The advantage of the ice cores is that they show us just how unusual it is for Greenland to be melting this fast,” Dr Osterberg said.

“We see that West Greenland melt really started accelerating about 20 years ago. Our study shows that the rapid rise in the West Greenland melt is a combination of specific weather patterns and an additional long-term warming trend over the last century.” – Climate News Network

In the high latitudes in both hemispheres, the polar ice is in retreat. Two studies support fears for the ice caps, north and south.

LONDON, 10 April, 2018 – New studies have confirmed, once again, the rapid melting of the polar ice in both hemispheres.

A British team has used satellite data to reveal that the retreat of the all-important grounding line of many Antarctic glaciers has accelerated to five times the historic level. And US scientists have confirmed that in Arctic waters the West Greenland ice sheet is now melting faster than at any time in the last 450 years.

Both studies deliver ominous evidence of the long-term consequences of climate change due to profligate human use of fossil fuels. The Greenland icecap holds enough water to raise global sea levels by seven metres. The West Antarctic ice sheet – where the latest study has identified most of the change – holds enough water to raise sea levels by up to five metres.

The UK measure of Antarctic ice retreat is important because it confirms on a wider scale what individual measurements of glacier retreat have already shown: that increasingly warm southern ocean waters are melting the ice at depth.

“This retreat has had a huge impact on inland glaciers, because releasing them from the sea bed removes friction, causing them to speed up and contribute to global sea level rise”

Depth in this study is critical: glaciers move slowly because the frozen rivers are “anchored” or grounded in bedrock as they flow off the continent, and then grounded again up to a kilometre deep off the continental shelf.

This applies a brake to the flow towards the open sea. The further from the coast the grounding line, the slower the glacier’s flow, the more stable the ice shelf, and the slower the consequent sea level rise.

Hannes Konrad of the University of Leeds in the UK and colleagues report in the journal Nature Geoscience that they used the European Space Agency’s satellite Cryosat-2 data to track the changes in the grounding line along 16,000 kilometres of southern polar coastline.

Around West Antarctica, more than a fifth of the ice sheet has retreated faster than the 25 metres or so a year that has been normal since the end of the last ice age. In some cases the retreat of the grounding line has been five times that rate. The retreat has been extreme in eight of the ice sheet’s 65 biggest glaciers.

Clear evidence

“Our study provides clear evidence that retreat is happening across the ice sheet due to ocean melting at its base, and not just at the few spots that have been mapped before now,” Dr Konrad said.

“This retreat has had a huge impact on inland glaciers, because releasing them from the sea bed removes friction, causing them to speed up and contribute to global sea level rise.”

Far to the north, ice is also melting. Erich Osterberg of Dartmouth College in the US and colleagues report in the journal Geophysical Research Letters that they collected seven ice cores from a remote zone in the West Greenland ice sheet where meltwater trickles down into the deeper snow and then freezes again: this “new” ice in the compacted snow provides scientists with a record of melting over time.

Longer record

Researchers have been watching the apparent acceleration of the summer melting of Greenland’s ice for decades: they have monitored ever faster rates of glacier flow and tried to identify direct influences on the surface of the ice sheet that might accelerate overall melting.

But direct observation of the northern hemisphere’s largest concentration of ice began only about five decades ago. The Dartmouth cores provide a total of almost five centuries of summer melt patterns.

“The ice core record ends about 450 years ago, so the modern melt rates in these cores are the highest of the whole record that we can see. The advantage of the ice cores is that they show us just how unusual it is for Greenland to be melting this fast,” Dr Osterberg said.

“We see that West Greenland melt really started accelerating about 20 years ago. Our study shows that the rapid rise in the West Greenland melt is a combination of specific weather patterns and an additional long-term warming trend over the last century.” – Climate News Network

Glacial melt will wreck ecosystems

Glacial Yukon Canada

The alarming rate of glacial shrinkage worldwide threatens our current way of life, from biodiversity to tourism, hydropower to clean water supply.

LONDON, 15 September, 2017 – Glaciers cover one-tenth of the planet’s land surface – but not for much longer.

Glaciers worldwide are in retreat, and losing mass. They are shrinking and melting, and that will create problems almost everywhere, according to new research.

Between 2003 and 2009, glaciers melted on a gargantuan scale, with an estimated 1,350 cubic kilometres of meltwater streamed from what had once been vast streams of slowly flowing ice.

Ice has been in retreat in the Gulf of Alaska, the Canadian Arctic, Greenland and Antarctica. In the European Alps summers have become measurably warmer during the last 30 years, snowfall has diminished and 54% of the ice cover in the mountains has disappeared since 1850. By 2100, Alpine summits may have lost around nine-tenths of the ice that still covered them in 2003. In South America, the glaciers of Bolivia lost almost 50% of their mass in the last 50 years. In western Canada, somewhere between 60% and 80% of the ice measured in 2005 will have disappeared, and flowed into the sea to raise sea levels everywhere.

And, says an international team of scientists, in the Proceedings of the National Academy of Sciences, the loss of mountain ice creates problems for the people who live downstream.

We don’t believe that the sheer enormity
of the impact of glacial shrinkage on our downstream
ecosystems has been fully integrated to date”

Glaciers in the basins of the Ganges, Brahmaputra and Indus rivers are right now losing 24 billion metric tons of ice a year: between 2003 and 2009, that added up to about a tenth of all the glacial ice lost everywhere in the world. Ice loss upstream means changes in the timing, magnitude and frequency of the flows downstream, and that in turn affects the levels of sediment, and the nutrients, both for the human populations who depend on the farmland in the valleys and plains below, but also for the natural ecosystems in the rivers, lakes and coastal zones.

It is time, the scientists argue, for some serious thinking: glacier loss cannot be separated from complexities such as changes in natural hazards such as flooding and drought, in agriculture, tourism, hydropower, cultural life and political economy.

We don’t believe that the sheer enormity of the impact of glacial shrinkage on our downstream ecosystems has been fully integrated to date. From biodiversity to tourism, from hydropower to clean water supply, the breadth of risk to our current way of life is vast. The first step must be a realignment in how we view glacial shrinkage, and a research agenda that acknowledges the risk to regions likely to be most affected,” says Alexander Milner, professor of river ecosystems at the University of Birmingham in the United Kingdom, who led the study.

Four tasks

He and colleagues, from Alaska, Switzerland, Norway, Austria, France, Iceland, Denmark, Italy and other UK universities, want the global science community to think about four big things.

They want new technologies to map the details of ice loss with greater precision. They want better global monitoring of the nutrients and contaminants that are now trickling at ever greater rates from glaciers into downstream waterways.They want to see better understanding of the impact of what scientists like to call “ecosystem services” delivered by glaciers – and that includes what happens to salmon habitats and sports fisheries. And they would like to see management plans for change in the most sensitive glacier regions, and that could include international legislation to protect what they call “strategic glacier-derived water resources”.

Researchers have been warning about glacial loss for many years: they have highlighted regional alarms in Greenland, central Asia, the Antarctic, and the Bolivian Andes.

They have firmly linked glacial loss to global warming driven by profligate human fossil fuel combustion and they have warned that such loss risks social change and potential catastrophe for millions.

Glacial water

So the latest study is a kind of summary of the research so far, and an attempt to identify what glaciologists, geographers, hydrologists and social scientists should do to understand the problems ahead, and identify steps to ameliorate some of the worst impacts. They see potential for conflict over access to dwindling water supplies downstream from what had once been great glacier systems.

And, they warn, there is even a religious dimension.

For example, thousands of pilgrims annually traverse the Gangotri Glacier in India, considering it a sacred spot, and in Peru and the Yukon Territory of Canada, indigenous people consider glaciers as gods. In Peru, the loss of ice and snow from mountain peaks is thus associated with the god’s departure and the end of the world. On the Tibetan Plateau, residents consider the glacierised Yulong Snow Mountain their spiritual home, but already 65% have recognised the necessity to potentially migrate to adapt to climate change and achieve a sustainable livelihood,” they write.

These social upheavals would clearly lead to implications across the wider array of services that human populations use from glacier-fed rivers.”
Climate News Network

The alarming rate of glacial shrinkage worldwide threatens our current way of life, from biodiversity to tourism, hydropower to clean water supply.

LONDON, 15 September, 2017 – Glaciers cover one-tenth of the planet’s land surface – but not for much longer.

Glaciers worldwide are in retreat, and losing mass. They are shrinking and melting, and that will create problems almost everywhere, according to new research.

Between 2003 and 2009, glaciers melted on a gargantuan scale, with an estimated 1,350 cubic kilometres of meltwater streamed from what had once been vast streams of slowly flowing ice.

Ice has been in retreat in the Gulf of Alaska, the Canadian Arctic, Greenland and Antarctica. In the European Alps summers have become measurably warmer during the last 30 years, snowfall has diminished and 54% of the ice cover in the mountains has disappeared since 1850. By 2100, Alpine summits may have lost around nine-tenths of the ice that still covered them in 2003. In South America, the glaciers of Bolivia lost almost 50% of their mass in the last 50 years. In western Canada, somewhere between 60% and 80% of the ice measured in 2005 will have disappeared, and flowed into the sea to raise sea levels everywhere.

And, says an international team of scientists, in the Proceedings of the National Academy of Sciences, the loss of mountain ice creates problems for the people who live downstream.

We don’t believe that the sheer enormity
of the impact of glacial shrinkage on our downstream
ecosystems has been fully integrated to date”

Glaciers in the basins of the Ganges, Brahmaputra and Indus rivers are right now losing 24 billion metric tons of ice a year: between 2003 and 2009, that added up to about a tenth of all the glacial ice lost everywhere in the world. Ice loss upstream means changes in the timing, magnitude and frequency of the flows downstream, and that in turn affects the levels of sediment, and the nutrients, both for the human populations who depend on the farmland in the valleys and plains below, but also for the natural ecosystems in the rivers, lakes and coastal zones.

It is time, the scientists argue, for some serious thinking: glacier loss cannot be separated from complexities such as changes in natural hazards such as flooding and drought, in agriculture, tourism, hydropower, cultural life and political economy.

We don’t believe that the sheer enormity of the impact of glacial shrinkage on our downstream ecosystems has been fully integrated to date. From biodiversity to tourism, from hydropower to clean water supply, the breadth of risk to our current way of life is vast. The first step must be a realignment in how we view glacial shrinkage, and a research agenda that acknowledges the risk to regions likely to be most affected,” says Alexander Milner, professor of river ecosystems at the University of Birmingham in the United Kingdom, who led the study.

Four tasks

He and colleagues, from Alaska, Switzerland, Norway, Austria, France, Iceland, Denmark, Italy and other UK universities, want the global science community to think about four big things.

They want new technologies to map the details of ice loss with greater precision. They want better global monitoring of the nutrients and contaminants that are now trickling at ever greater rates from glaciers into downstream waterways.They want to see better understanding of the impact of what scientists like to call “ecosystem services” delivered by glaciers – and that includes what happens to salmon habitats and sports fisheries. And they would like to see management plans for change in the most sensitive glacier regions, and that could include international legislation to protect what they call “strategic glacier-derived water resources”.

Researchers have been warning about glacial loss for many years: they have highlighted regional alarms in Greenland, central Asia, the Antarctic, and the Bolivian Andes.

They have firmly linked glacial loss to global warming driven by profligate human fossil fuel combustion and they have warned that such loss risks social change and potential catastrophe for millions.

Glacial water

So the latest study is a kind of summary of the research so far, and an attempt to identify what glaciologists, geographers, hydrologists and social scientists should do to understand the problems ahead, and identify steps to ameliorate some of the worst impacts. They see potential for conflict over access to dwindling water supplies downstream from what had once been great glacier systems.

And, they warn, there is even a religious dimension.

For example, thousands of pilgrims annually traverse the Gangotri Glacier in India, considering it a sacred spot, and in Peru and the Yukon Territory of Canada, indigenous people consider glaciers as gods. In Peru, the loss of ice and snow from mountain peaks is thus associated with the god’s departure and the end of the world. On the Tibetan Plateau, residents consider the glacierised Yulong Snow Mountain their spiritual home, but already 65% have recognised the necessity to potentially migrate to adapt to climate change and achieve a sustainable livelihood,” they write.

These social upheavals would clearly lead to implications across the wider array of services that human populations use from glacier-fed rivers.”
Climate News Network

Swiss trees swelter as climate warms

Foresters are being urged to plant tree species resilient to climate change to save the timber industry as Swiss trees swelter.

LONDON, 16 August, 2017 – The most important tree for Switzerland’s forestry industry, the Norway spruce, is in danger of dying out in much of the country because it cannot adapt fast enough as Swiss trees swelter in the rising temperatures.

Caroline Heiri, the lead scientist at the Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), described the findings as “astonishing” and said urgent action was needed to save Switzerland’s forests by planting saplings that can survive the conditions which will occur later this century as the trees grow to maturity.

Switzerland is already acutely aware of the dangers of climate change to its economy as its glaciers shrink and the Alpine snow line rises. This has already forced some lower ski resorts out of business and shortened the season for others.

In order to see what effect climate change would have on another key industry, forestry, scientists planted 16,000 seedlings of the three most important timber species in a nursery to see how they would respond. The seedlings had been brought from nearly 250 different forest locations at different heights, temperatures and water availability.

Long interval

Although all trees can evolve and adapt to climate change over time, there is a gap of up to a hundred years between generations, so the rapid temperature change expected this century will often be too fast for adaptation to happen.

The three species tested were Norway spruce, silver fir and European beech, and the seedlings came from all regions of the country. The researchers studied their growth and monitored the timing of buds breaking in the spring and growth ending in late summer.

Although the seedlings were all planted together in one vast nursery, they maintained the growth patterns that corresponded to the climates at their place of origin.

The scientists, who work in conjunction with the Federal Office for the Environment, concluded that of the three species the Norway spruce had over the centuries adapted very closely to the local climates where it grows. This means that the growing trees and their descendants in these locations will not thrive in rising temperatures, especially in regions which are already warming.

Adaptable fir

The European beech also showed local adaptation, but it was less pronounced than with the spruce. The silver fir, on the other hand, had apparently made few adjustments and thrived in many different conditions, making it a far better bet for Switzerland’s future forests.

The results, published by WSL, show that the Norway spruce, the tree most favoured by the Swiss forestry sector, will be at risk throughout the country from advancing climate change by the end of the 21st century.

Urgent action is required to adapt the forests, and the scientists advise planting Norway spruce only on sites with a good water supply and using seeds originating from warmer habitats.

“If we use seeds from trees in warmer and drier regions, we will at least have a chance for these species to thrive for yet another forest generation”

This will mean they are likely to be already adapted to regions that are currently cool but have started warming. The scientists also suggest planting spruce from the valley floors higher up the mountains, or obtaining specimens from other countries where the tree is already accustomed to warmer and drier climes.

A similar procedure could be applied for European beech, taking seeds from growth locations that are already dry today. “If we use seeds from trees in warmer and drier regions, we will at least have a chance for these species to thrive for yet another forest generation. This way, our forests will remain stable and protect us against natural hazards”, says Caroline Heiri.

The best option, however, is to opt for trees tolerant of much wider environmental conditions, like the silver fir. It may prove Swiss foresters’ major hope for the future, the research concludes. Climate News Network

Foresters are being urged to plant tree species resilient to climate change to save the timber industry as Swiss trees swelter.

LONDON, 16 August, 2017 – The most important tree for Switzerland’s forestry industry, the Norway spruce, is in danger of dying out in much of the country because it cannot adapt fast enough as Swiss trees swelter in the rising temperatures.

Caroline Heiri, the lead scientist at the Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), described the findings as “astonishing” and said urgent action was needed to save Switzerland’s forests by planting saplings that can survive the conditions which will occur later this century as the trees grow to maturity.

Switzerland is already acutely aware of the dangers of climate change to its economy as its glaciers shrink and the Alpine snow line rises. This has already forced some lower ski resorts out of business and shortened the season for others.

In order to see what effect climate change would have on another key industry, forestry, scientists planted 16,000 seedlings of the three most important timber species in a nursery to see how they would respond. The seedlings had been brought from nearly 250 different forest locations at different heights, temperatures and water availability.

Long interval

Although all trees can evolve and adapt to climate change over time, there is a gap of up to a hundred years between generations, so the rapid temperature change expected this century will often be too fast for adaptation to happen.

The three species tested were Norway spruce, silver fir and European beech, and the seedlings came from all regions of the country. The researchers studied their growth and monitored the timing of buds breaking in the spring and growth ending in late summer.

Although the seedlings were all planted together in one vast nursery, they maintained the growth patterns that corresponded to the climates at their place of origin.

The scientists, who work in conjunction with the Federal Office for the Environment, concluded that of the three species the Norway spruce had over the centuries adapted very closely to the local climates where it grows. This means that the growing trees and their descendants in these locations will not thrive in rising temperatures, especially in regions which are already warming.

Adaptable fir

The European beech also showed local adaptation, but it was less pronounced than with the spruce. The silver fir, on the other hand, had apparently made few adjustments and thrived in many different conditions, making it a far better bet for Switzerland’s future forests.

The results, published by WSL, show that the Norway spruce, the tree most favoured by the Swiss forestry sector, will be at risk throughout the country from advancing climate change by the end of the 21st century.

Urgent action is required to adapt the forests, and the scientists advise planting Norway spruce only on sites with a good water supply and using seeds originating from warmer habitats.

“If we use seeds from trees in warmer and drier regions, we will at least have a chance for these species to thrive for yet another forest generation”

This will mean they are likely to be already adapted to regions that are currently cool but have started warming. The scientists also suggest planting spruce from the valley floors higher up the mountains, or obtaining specimens from other countries where the tree is already accustomed to warmer and drier climes.

A similar procedure could be applied for European beech, taking seeds from growth locations that are already dry today. “If we use seeds from trees in warmer and drier regions, we will at least have a chance for these species to thrive for yet another forest generation. This way, our forests will remain stable and protect us against natural hazards”, says Caroline Heiri.

The best option, however, is to opt for trees tolerant of much wider environmental conditions, like the silver fir. It may prove Swiss foresters’ major hope for the future, the research concludes. Climate News Network

Marine hotspots raise eastern US sea levels

Suddenly marine hotspots are raising sea levels in the eastern US. It may not be a permanent hazard – but it is a warning.

LONDON, 12 August, 2017 – Sea level rise and catastrophic coastal flooding could come early to the US Atlantic coast, thanks to marine hotspots. So sea water in the streets of Florida or drowned towns on offshore islands will not necessarily be blamed upon global warming.

Florida scientists have identified a series of these natural marine “hotspots” where the seas are rising far faster than the oceans as a whole, in response to glacial melting and thermal expansion of the waters.

One of these – stretching from Cape Hatteras to Miami – was driven by the overlapping effects of El Niño, that periodic blister of heat most obvious in the eastern Pacific, and the North Atlantic Oscillation, another entirely natural periodic shift in atmosphere and current that can pile up the ocean waters.

Sixfold increase

Between 2011 and 2015, the seas off the US Atlantic coast rose more than six times the global average, according to new research in the journal Geophysical Research Letters.

“The important point here is that smooth projections of sea level rise do not capture this variability, so adverse effects of sea level rise may occur before they are predicted to happen,” said Andrea Dutton, an earth scientist at the University of Florida.

“The entire US Atlantic coastline is vulnerable to these hot spots that may amplify the severity of coastal flooding.”

The words “sea level” are misleading: for a range of reasons – from gravitational anomalies on the sea floor to the intrusion of a warm current, or a pattern of high winds – the sea’s contours ripple up and down imperceptibly around the planet.

Consistent increase

Since the first concerns about inexorable global warming, as a response to the combustion of fossil fuels that deposit ever greater quantities of greenhouse gases such as carbon dioxide in the atmosphere, climate scientists have measured a slow but consistent increase in sea levels everywhere.

And climate scientists have repeatedly warned that, as a consequence, storms could hammer coastal cities with increasing ferocity, that flood risks on both coasts will multiply and that the US could soon see its own “climate refugees” as ever greater numbers leave the most vulnerable coastal towns and cities.

Although sea level rise threatens low-lying islands and atolls everywhere, one of the world’s most vulnerable locations is Tangier Island, off Maryland. The island authorities have been reassured by US President Trump that they won’t suffer from climate change, but that alone may not be enough to protect the region.

“It’s amazing to see construction along the East Coast. That’s the worst place to build anything. We need to understand that the ocean is coming”

The new study grew from the discovery that a river lagoon on the Atlantic coast of Florida had become conspicuously saltier after 2011. Arnoldo Valle-Levinson, a civil and coastal engineer at the University of Florida, checked local tide gauges, to see that seas in the region were rising 10 times faster than the long-term rate measured off the coast.

And the same was true all the way to Cape Hatteras. But sea level rise was diminished north of Cape Hatteras, and when researchers looked again at the pattern of tides in the past, they found that “comparable, short-lived”  accelerations of sea level rise had happened in the past 95 years.

It isn’t clear that such hotspots are likely to become permanent, and it isn’t obvious that global warming is in this case a factor. But global sea level rise driven by global warming is likely to make such unexpected lurches in sea levels more hazardous when they do happen. The researchers once again see the phenomenon as a good reason for reducing carbon dioxide emissions.

“It’s amazing to see construction along the East Coast. That’s the worst place to build anything,” said Professor Valle-Levinson, “We need to understand that the ocean is coming.” – Climate News Network

Suddenly marine hotspots are raising sea levels in the eastern US. It may not be a permanent hazard – but it is a warning.

LONDON, 12 August, 2017 – Sea level rise and catastrophic coastal flooding could come early to the US Atlantic coast, thanks to marine hotspots. So sea water in the streets of Florida or drowned towns on offshore islands will not necessarily be blamed upon global warming.

Florida scientists have identified a series of these natural marine “hotspots” where the seas are rising far faster than the oceans as a whole, in response to glacial melting and thermal expansion of the waters.

One of these – stretching from Cape Hatteras to Miami – was driven by the overlapping effects of El Niño, that periodic blister of heat most obvious in the eastern Pacific, and the North Atlantic Oscillation, another entirely natural periodic shift in atmosphere and current that can pile up the ocean waters.

Sixfold increase

Between 2011 and 2015, the seas off the US Atlantic coast rose more than six times the global average, according to new research in the journal Geophysical Research Letters.

“The important point here is that smooth projections of sea level rise do not capture this variability, so adverse effects of sea level rise may occur before they are predicted to happen,” said Andrea Dutton, an earth scientist at the University of Florida.

“The entire US Atlantic coastline is vulnerable to these hot spots that may amplify the severity of coastal flooding.”

The words “sea level” are misleading: for a range of reasons – from gravitational anomalies on the sea floor to the intrusion of a warm current, or a pattern of high winds – the sea’s contours ripple up and down imperceptibly around the planet.

Consistent increase

Since the first concerns about inexorable global warming, as a response to the combustion of fossil fuels that deposit ever greater quantities of greenhouse gases such as carbon dioxide in the atmosphere, climate scientists have measured a slow but consistent increase in sea levels everywhere.

And climate scientists have repeatedly warned that, as a consequence, storms could hammer coastal cities with increasing ferocity, that flood risks on both coasts will multiply and that the US could soon see its own “climate refugees” as ever greater numbers leave the most vulnerable coastal towns and cities.

Although sea level rise threatens low-lying islands and atolls everywhere, one of the world’s most vulnerable locations is Tangier Island, off Maryland. The island authorities have been reassured by US President Trump that they won’t suffer from climate change, but that alone may not be enough to protect the region.

“It’s amazing to see construction along the East Coast. That’s the worst place to build anything. We need to understand that the ocean is coming”

The new study grew from the discovery that a river lagoon on the Atlantic coast of Florida had become conspicuously saltier after 2011. Arnoldo Valle-Levinson, a civil and coastal engineer at the University of Florida, checked local tide gauges, to see that seas in the region were rising 10 times faster than the long-term rate measured off the coast.

And the same was true all the way to Cape Hatteras. But sea level rise was diminished north of Cape Hatteras, and when researchers looked again at the pattern of tides in the past, they found that “comparable, short-lived”  accelerations of sea level rise had happened in the past 95 years.

It isn’t clear that such hotspots are likely to become permanent, and it isn’t obvious that global warming is in this case a factor. But global sea level rise driven by global warming is likely to make such unexpected lurches in sea levels more hazardous when they do happen. The researchers once again see the phenomenon as a good reason for reducing carbon dioxide emissions.

“It’s amazing to see construction along the East Coast. That’s the worst place to build anything,” said Professor Valle-Levinson, “We need to understand that the ocean is coming.” – Climate News Network

Greenland’s shrinking cloud cover speeds melt

More sunshine penetrating Greenland’s shrinking cloud cover explains why its icy mountains are turning increasingly slushy.

LONDON, 2 July, 2017 – British and Belgian scientists think they understand why part of the Arctic is melting at a faster rate. For once, they don’t blame global atmospheric warming. But they have found a marked change during the last two decades, with Greenland’s shrinking cloud cover letting more sunshine reach the surface. So the link with climate change remains.

Their thesis, reported in the journal Science Advances, is that a drop in cloud cover and more summer sunshine means that more radiation hits the snows to deliver more energy for melting.

And they calculate that just a 1% reduction in summer cloud cover means an extra 27 billion metric tons of melting ice at the island’s surface. This is, roughly, the annual domestic water supply of the United States.

Their conclusion may not be the end of the matter, though. That Greenland’s ice is melting at an increasing rate is not in doubt.

Varied explanations

But previous studies have linked the acceleration to a darkening of the snows, to the insulating effects of cloud cover, and even to the temperature of the bedrock below the glaciers.

But Greenland has lost 4,000 billion tons of ice since 1995 and, for the moment, scientists think they can attribute much of this to an increase in direct summer sunlight.

“The impact of increased sunshine during summer is large, it explains about two-thirds of Greenland’s melting signal in recent decades,” said Stefan Hofer, a doctoral student at the University of Bristol, UK, who led the study.

“Until now we thought that the recent Greenland melt is caused almost exclusively by higher temperatures and the resulting feedbacks. Our study shows that there is more to the story than the local increase in temperatures. And the change in cloud cover isn’t just a blip, it’s been happening for the last two decades. That was a big surprise.”

“We are seeing changes in the large-scale circulation patterns, which leads to more frequent sunshine and higher amounts of solar energy reaching the surface of the ice sheet”

That, however, is not the only contributing factor. The scientists found that although summer cloud cover decreased by an average of 0.9% a year between 1995 and 2009, this might be connected to a meteorological phenomenon called the North Atlantic Oscillation, a natural cycle that four years ago was linked to dramatic melting in Greenland.

“We are seeing changes in the large-scale circulation patterns, which leads to more frequent sunshine and higher amounts of solar energy reaching the surface of the ice sheet,” said Jonathan Bamber, a geographer at the University of Bristol and president of the European Geosciences Union.

“These changes in large-scale circulation patterns during summer are especially pronounced over the Arctic and the North Atlantic. The state shift in atmospheric circulation is unprecedented in the observational record, which goes back as far as 1850.”

Professor Bamber continued: “This highly unusual state of the atmosphere has been linked to record low sea ice cover during summer over the Arctic Ocean. This highlights the coupled nature of the climate system and the consequences of changes in one component on another.” – Climate News Network

More sunshine penetrating Greenland’s shrinking cloud cover explains why its icy mountains are turning increasingly slushy.

LONDON, 2 July, 2017 – British and Belgian scientists think they understand why part of the Arctic is melting at a faster rate. For once, they don’t blame global atmospheric warming. But they have found a marked change during the last two decades, with Greenland’s shrinking cloud cover letting more sunshine reach the surface. So the link with climate change remains.

Their thesis, reported in the journal Science Advances, is that a drop in cloud cover and more summer sunshine means that more radiation hits the snows to deliver more energy for melting.

And they calculate that just a 1% reduction in summer cloud cover means an extra 27 billion metric tons of melting ice at the island’s surface. This is, roughly, the annual domestic water supply of the United States.

Their conclusion may not be the end of the matter, though. That Greenland’s ice is melting at an increasing rate is not in doubt.

Varied explanations

But previous studies have linked the acceleration to a darkening of the snows, to the insulating effects of cloud cover, and even to the temperature of the bedrock below the glaciers.

But Greenland has lost 4,000 billion tons of ice since 1995 and, for the moment, scientists think they can attribute much of this to an increase in direct summer sunlight.

“The impact of increased sunshine during summer is large, it explains about two-thirds of Greenland’s melting signal in recent decades,” said Stefan Hofer, a doctoral student at the University of Bristol, UK, who led the study.

“Until now we thought that the recent Greenland melt is caused almost exclusively by higher temperatures and the resulting feedbacks. Our study shows that there is more to the story than the local increase in temperatures. And the change in cloud cover isn’t just a blip, it’s been happening for the last two decades. That was a big surprise.”

“We are seeing changes in the large-scale circulation patterns, which leads to more frequent sunshine and higher amounts of solar energy reaching the surface of the ice sheet”

That, however, is not the only contributing factor. The scientists found that although summer cloud cover decreased by an average of 0.9% a year between 1995 and 2009, this might be connected to a meteorological phenomenon called the North Atlantic Oscillation, a natural cycle that four years ago was linked to dramatic melting in Greenland.

“We are seeing changes in the large-scale circulation patterns, which leads to more frequent sunshine and higher amounts of solar energy reaching the surface of the ice sheet,” said Jonathan Bamber, a geographer at the University of Bristol and president of the European Geosciences Union.

“These changes in large-scale circulation patterns during summer are especially pronounced over the Arctic and the North Atlantic. The state shift in atmospheric circulation is unprecedented in the observational record, which goes back as far as 1850.”

Professor Bamber continued: “This highly unusual state of the atmosphere has been linked to record low sea ice cover during summer over the Arctic Ocean. This highlights the coupled nature of the climate system and the consequences of changes in one component on another.” – Climate News Network