Tag Archives: Sea levels

Polar ice melt raises sea level dangers

polar ice

Greenland’s polar ice is now melting far faster than 30 years ago, Antarctic ice is retreating at an accelerating rate, and sea levels are creeping up.

LONDON, 19 March, 2020 – Greenland and Antarctica, the two greatest stores of frozen water on the planet, are now losing polar ice at a rate at least six times faster than they were at the close of the last century.

The fact that polar ice is melting ever faster has been clear for a decade, but the latest research is authoritative.

To establish the rate of loss, 89 polar scientists from 50 of the world’s great research institutions looked at data from 26 separate surveys between 1992 and 2018, along with information from 11 different satellite missions.

Gloomiest forecasts

And the finding is in line with the worst-case scenarios considered by the Intergovernmental Panel on Climate Change (IPCC). If this rate of increase continues, sea levels at the close of this century will be at least 17 centimetres higher than the gloomiest official forecasts so far.

Between 1992 and 2017, the global sea level rose by 17.8 millimetres, as 6.4 trillion tonnes of polar ice turned to water and trickled into the oceans – 10.6 mm from Greenland and 7.2 mm from Antarctica.

In the last decade of the last century, the northern and southern icecaps dwindled at the rate of 81 billion tonnes a year. In the last decade, this had risen to 475 billion tonnes a year. This means that a third of all sea level rise is now caused by the loss of polar ice.

The most recent assessment by the IPCC is that, by 2100, sea levels will have risen by 53 cms, putting 360 million people who live at sea level at some risk.

“This would mean 400 million people at risk of annual coastal flooding by 2100”

But the latest finding from the Ice Sheet Mass Balance Inter-comparison Exercise (IMBIE) scientists is that seas will rise even higher, and even more people will have to move.

“Every centimetre of sea level rise leads to coastal flooding and coastal erosion, disrupting people’s lives around the planet,” said Andrew Shepherd, professor of Earth observation at the University of Leeds, UK, as he and colleagues published their findings of Greenland losses in Nature journal.

“If Antarctica and Greenland continue to track the worst-case climate warning scenario, they will cause an extra 17 cms of sea level rise by the end of the century.

“This would mean 400 million people at risk of annual coastal flooding by 2100. These are not unlikely events with small impacts; they are already under way and will be devastating for coastal communities.”

Global picture

Professor Shepherd and his IMBIE colleagues established almost two years ago that Antarctica was losing ice at an ever-accelerating rate, but the Greenland survey completes the global picture.

And it remains a picture in which the Arctic seems to be warming at an accelerating rate and sea levels seem to be rising ever faster.

This is not just because the polar ice caps are melting, but also because, almost everywhere, mountain glaciers are in retreat, and the oceans are expanding as sea temperatures rise in response to the steady warming of the planetary atmosphere. – Climate News Network

Greenland’s polar ice is now melting far faster than 30 years ago, Antarctic ice is retreating at an accelerating rate, and sea levels are creeping up.

LONDON, 19 March, 2020 – Greenland and Antarctica, the two greatest stores of frozen water on the planet, are now losing polar ice at a rate at least six times faster than they were at the close of the last century.

The fact that polar ice is melting ever faster has been clear for a decade, but the latest research is authoritative.

To establish the rate of loss, 89 polar scientists from 50 of the world’s great research institutions looked at data from 26 separate surveys between 1992 and 2018, along with information from 11 different satellite missions.

Gloomiest forecasts

And the finding is in line with the worst-case scenarios considered by the Intergovernmental Panel on Climate Change (IPCC). If this rate of increase continues, sea levels at the close of this century will be at least 17 centimetres higher than the gloomiest official forecasts so far.

Between 1992 and 2017, the global sea level rose by 17.8 millimetres, as 6.4 trillion tonnes of polar ice turned to water and trickled into the oceans – 10.6 mm from Greenland and 7.2 mm from Antarctica.

In the last decade of the last century, the northern and southern icecaps dwindled at the rate of 81 billion tonnes a year. In the last decade, this had risen to 475 billion tonnes a year. This means that a third of all sea level rise is now caused by the loss of polar ice.

The most recent assessment by the IPCC is that, by 2100, sea levels will have risen by 53 cms, putting 360 million people who live at sea level at some risk.

“This would mean 400 million people at risk of annual coastal flooding by 2100”

But the latest finding from the Ice Sheet Mass Balance Inter-comparison Exercise (IMBIE) scientists is that seas will rise even higher, and even more people will have to move.

“Every centimetre of sea level rise leads to coastal flooding and coastal erosion, disrupting people’s lives around the planet,” said Andrew Shepherd, professor of Earth observation at the University of Leeds, UK, as he and colleagues published their findings of Greenland losses in Nature journal.

“If Antarctica and Greenland continue to track the worst-case climate warning scenario, they will cause an extra 17 cms of sea level rise by the end of the century.

“This would mean 400 million people at risk of annual coastal flooding by 2100. These are not unlikely events with small impacts; they are already under way and will be devastating for coastal communities.”

Global picture

Professor Shepherd and his IMBIE colleagues established almost two years ago that Antarctica was losing ice at an ever-accelerating rate, but the Greenland survey completes the global picture.

And it remains a picture in which the Arctic seems to be warming at an accelerating rate and sea levels seem to be rising ever faster.

This is not just because the polar ice caps are melting, but also because, almost everywhere, mountain glaciers are in retreat, and the oceans are expanding as sea temperatures rise in response to the steady warming of the planetary atmosphere. – Climate News Network

Sandy beaches may succumb to rising seas

Ever higher seas are already eroding shorelines and flooding coasts. Soon the waves could wash away half the world’s sandy beaches.

LONDON, 5 March, 2020 – Right now, around a third of the world’s coastline is made up of sandy beaches and dunes which slope gently and softly to the sea. By the end of the century, these could make up only one-sixth of the frontier between land and ocean. Sea level rise driven by global heating could sweep half of them away.

Beaches are nature’s buffers between eroding land and tempestuous sea: they protect the coast, they provide a unique habitat for wildlife, and they have become powerful socio-economic resources.

But the paradise for surfers around sunlit Australia is almost certain to be diminished in the coming climate crisis as the waves lap ever higher, storm surges sweep away vast volumes of sand, and seas flood low-lying coasts. And – according to new European research in the journal Nature Climate Change – what is true for Australia is true for much of the rest of the world.

How much beach is lost will depend on how nations respond to the challenge of climate change. But in the worst-case scenario, Australia and Canada could each say goodbye to nearly 15,000 kilometres of sandy shore by 2100. Chile could lose more than 6,000 km, Mexico, China and the US more than 5,000 km, Russia more than 4,000 km and Argentina more than 3,000 km.

“Much of the world’s coast is already eroding, which could get worse with sea level rise”

And that’s the outlook for countries with vast coastlines. Some could fare even worse. Guinea-Bissau and The Gambia in West Africa, for instance, could lose 60% of their beaches.

The European scientists looked at more than 30 years of satellite data on coastal change – from 1984 to 2015 – and 82 years of climate and sea level predictions from a range of climate models. They also simulated 100 million storm events.

There is plenty of evidence that the world’s seas are responding to climate change; that sea levels are rising in response to warmer atmospheric temperatures driven by profligate combustion of fossil fuels; and that coastal flooding is likely to become more extreme.

But the detailed questions remain: how exactly will ever-higher tides exact their toll of the wetlands, mangrove forests, estuaries, cliff faces, rocky coasts, storm beaches and dunes that serve as a barrier between the maritime cities and towns of the world, and the saltwater? The researchers found that even in the more hopeful scenarios, there would be considerable losses.

UK backs study

But if nations delivered on the promise made in Paris in 2015 – a promise that still has to be backed up by urgent action on a global scale – to contain global heating to “well below” a maximum of 2°C by 2100, then perhaps 40% of the projected erosion of beaches could be halted.

Beaches are natural features of tidal landscapes: sand swept away by violent storms is eventually replaced by silt carried down the rivers to the coasts. The shoreline has always changed. But change is accelerating. Scientists in the UK have endorsed the European study.

“Much of the world’s coast is already eroding, which could get worse with sea level rise,” said Sally Brown, of Bournemouth University. Bournemouth is a famous British seaside resort.

“Building defences helps maintain coastline position, but defences are known to reduce beach width or depth over multiple decades. Responding to sea level rise means looking strategically at how and where we defend coasts today, which may mean protecting only limited parts of the coast.” – Climate News Network

Ever higher seas are already eroding shorelines and flooding coasts. Soon the waves could wash away half the world’s sandy beaches.

LONDON, 5 March, 2020 – Right now, around a third of the world’s coastline is made up of sandy beaches and dunes which slope gently and softly to the sea. By the end of the century, these could make up only one-sixth of the frontier between land and ocean. Sea level rise driven by global heating could sweep half of them away.

Beaches are nature’s buffers between eroding land and tempestuous sea: they protect the coast, they provide a unique habitat for wildlife, and they have become powerful socio-economic resources.

But the paradise for surfers around sunlit Australia is almost certain to be diminished in the coming climate crisis as the waves lap ever higher, storm surges sweep away vast volumes of sand, and seas flood low-lying coasts. And – according to new European research in the journal Nature Climate Change – what is true for Australia is true for much of the rest of the world.

How much beach is lost will depend on how nations respond to the challenge of climate change. But in the worst-case scenario, Australia and Canada could each say goodbye to nearly 15,000 kilometres of sandy shore by 2100. Chile could lose more than 6,000 km, Mexico, China and the US more than 5,000 km, Russia more than 4,000 km and Argentina more than 3,000 km.

“Much of the world’s coast is already eroding, which could get worse with sea level rise”

And that’s the outlook for countries with vast coastlines. Some could fare even worse. Guinea-Bissau and The Gambia in West Africa, for instance, could lose 60% of their beaches.

The European scientists looked at more than 30 years of satellite data on coastal change – from 1984 to 2015 – and 82 years of climate and sea level predictions from a range of climate models. They also simulated 100 million storm events.

There is plenty of evidence that the world’s seas are responding to climate change; that sea levels are rising in response to warmer atmospheric temperatures driven by profligate combustion of fossil fuels; and that coastal flooding is likely to become more extreme.

But the detailed questions remain: how exactly will ever-higher tides exact their toll of the wetlands, mangrove forests, estuaries, cliff faces, rocky coasts, storm beaches and dunes that serve as a barrier between the maritime cities and towns of the world, and the saltwater? The researchers found that even in the more hopeful scenarios, there would be considerable losses.

UK backs study

But if nations delivered on the promise made in Paris in 2015 – a promise that still has to be backed up by urgent action on a global scale – to contain global heating to “well below” a maximum of 2°C by 2100, then perhaps 40% of the projected erosion of beaches could be halted.

Beaches are natural features of tidal landscapes: sand swept away by violent storms is eventually replaced by silt carried down the rivers to the coasts. The shoreline has always changed. But change is accelerating. Scientists in the UK have endorsed the European study.

“Much of the world’s coast is already eroding, which could get worse with sea level rise,” said Sally Brown, of Bournemouth University. Bournemouth is a famous British seaside resort.

“Building defences helps maintain coastline position, but defences are known to reduce beach width or depth over multiple decades. Responding to sea level rise means looking strategically at how and where we defend coasts today, which may mean protecting only limited parts of the coast.” – Climate News Network

North Sea dams could save Europe’s coasts

There is a way to stop Europe’s coastal cities from vanishing below the waves – enclose the North Sea. But there’s a simpler solution.

LONDON, 4 March, 2020 − Two European scientists have proposed the ultimate flood barrier: they want to dam the North Sea and the English Channel with more than 600 kilometres (373 miles) of sea wall.

This would protect 15 nations in western Europe against the ravages of what could one day be 10 metres (33 feet) of sea level rise. It would ultimately turn the North Sea into a freshwater lake and, at up to €500 billion (£435 bn) or more, represent the single most costly piece of engineering ever.

But, the pair reason, to do nothing could cost the people of Europe perhaps 10 times as much as coasts eroded, the sea overwhelmed the Low Countries, reshaped the contours of a continent and forced 25 million people to move inland.

In their paper in the Bulletin of the American Meteorological SocietySjoerd Groeskamp of the Royal Netherlands Institute for Sea Research and Joakim Kjellsson of Geomar, the Helmholtz oceanographic research centre in Kiel, Germany, concede that what they propose “may seem an overwhelming and unrealistic solution at first.”

But compared with the cost of inaction, or the cost of managed retreat from the coastline that would displace millions, it could be the cheapest option. “It might be impossible to truly fathom the magnitude of the threat that global-mean sea level rise poses,” they warn.

Least bad option

Global average temperatures have risen by 1°C and sea levels by 21 cms (8 inches) since 1880. Sea level rise lags behind atmospheric warming, but the guess is that every degree Celsius in the air will be followed eventually by 2.3 metres (7.5 feet) of higher seas.

By 2100, temperatures could have risen more than 3°C and sea levels by up to 1.5 metres (5 feet). If nations carry on burning fossil fuels the icecaps will melt inexorably, and by 2500 seas could have risen by 10 metres.

“The best solution will always be the treatment of the cause: human-caused climate change,” they write. However, if nations do not act to control the greenhouse gas emissions and forest destruction that cause global heating, and ever higher tides, then solutions such as the North European Enclosure Dam, known for short as NEED, are the only option.

The two researchers propose a barrier, a dike of sloping sides 50 metres wide across the North Sea from Bergen in Norway to the north-east tip of Scotland, via the Shetland and Orkney Islands.

This would be 475 kms (295 miles) long, with an average depth of 127 metres (417 feet), but would have to cross a trench more than 300 metres (985 feet) deep. To withstand continued sea level rise beyond 2500, it would need to be 20 metres or more above the Atlantic waves.

“This dam is mainly a call to do something about climate change now. If we do nothing, then this extreme dam might just be the only solution”

The 160 kms (100 miles) of sea defence from south-west England to the westernmost point of France would be a little less problematic: sea depths are hardly more than 100 metres (330 feet).

But the engineers would also have to factor in the 40,000 cubic metres of river water that would discharge into this enclosed basin every second. This would mean the same volume would need pumping continuously into the Atlantic on the far side of the dikes.

Since the barrier would enclose a number of the world’s great shipping ports, there would have to be sluice gates to let the big ships through, or alternatively new ports on the ocean side of the barriers.

The very nature of the enclosed North Sea would begin to change. Within a decade or two, it would start to turn into a freshwater lake: it would be the end of centuries of a fishing industry.

It could – the scientists admit their calculations are of the “back of an envelope” variety – be done. They scaled up the costs of the world’s largest dikes so far in the Netherlands and South Korea, to calculate the 51 billion tonnes of sand needed for the project. This is about what the world uses every year in construction.

Technology tested

They note that fixed seabed oil platforms have been constructed to a depth of 500 metres (1,640 feet), so engineers already know how to do such things. Pumps of the scale required to handle the incoming river discharges are already in use, but they would be needed in their hundreds.

And although the cost would reach somewhere between €250-550 bn (£220-480 bn), this − spread over the 20 years the project would take − would represent only at most 0.32% of the gross domestic product of the UK, Netherlands, Germany, Belgium and Denmark combined: the five nations with most to lose from the rising tides.

It would, the authors argue, cost just the Netherlands – which already has 3,600 km (2,240 miles) of flood protection − a third of that sum to defend against sea level rises of only 1.5 metres. The good news is that, if such a project worked for western Europe, then the same techniques could enclose the Irish Sea, the Mediterranean, the Red Sea and the Persian Gulf.

“This dam makes it almost tangible what the consequences of continued sea level rise will be; a rise of 10 metres by the year 2500 according to the bleakest scenarios,” said Dr Groeskamp.

“This dam is therefore mainly a call to do something about climate change now. If we do nothing, then this extreme dam might just be the only solution.” − Climate News Network

There is a way to stop Europe’s coastal cities from vanishing below the waves – enclose the North Sea. But there’s a simpler solution.

LONDON, 4 March, 2020 − Two European scientists have proposed the ultimate flood barrier: they want to dam the North Sea and the English Channel with more than 600 kilometres (373 miles) of sea wall.

This would protect 15 nations in western Europe against the ravages of what could one day be 10 metres (33 feet) of sea level rise. It would ultimately turn the North Sea into a freshwater lake and, at up to €500 billion (£435 bn) or more, represent the single most costly piece of engineering ever.

But, the pair reason, to do nothing could cost the people of Europe perhaps 10 times as much as coasts eroded, the sea overwhelmed the Low Countries, reshaped the contours of a continent and forced 25 million people to move inland.

In their paper in the Bulletin of the American Meteorological SocietySjoerd Groeskamp of the Royal Netherlands Institute for Sea Research and Joakim Kjellsson of Geomar, the Helmholtz oceanographic research centre in Kiel, Germany, concede that what they propose “may seem an overwhelming and unrealistic solution at first.”

But compared with the cost of inaction, or the cost of managed retreat from the coastline that would displace millions, it could be the cheapest option. “It might be impossible to truly fathom the magnitude of the threat that global-mean sea level rise poses,” they warn.

Least bad option

Global average temperatures have risen by 1°C and sea levels by 21 cms (8 inches) since 1880. Sea level rise lags behind atmospheric warming, but the guess is that every degree Celsius in the air will be followed eventually by 2.3 metres (7.5 feet) of higher seas.

By 2100, temperatures could have risen more than 3°C and sea levels by up to 1.5 metres (5 feet). If nations carry on burning fossil fuels the icecaps will melt inexorably, and by 2500 seas could have risen by 10 metres.

“The best solution will always be the treatment of the cause: human-caused climate change,” they write. However, if nations do not act to control the greenhouse gas emissions and forest destruction that cause global heating, and ever higher tides, then solutions such as the North European Enclosure Dam, known for short as NEED, are the only option.

The two researchers propose a barrier, a dike of sloping sides 50 metres wide across the North Sea from Bergen in Norway to the north-east tip of Scotland, via the Shetland and Orkney Islands.

This would be 475 kms (295 miles) long, with an average depth of 127 metres (417 feet), but would have to cross a trench more than 300 metres (985 feet) deep. To withstand continued sea level rise beyond 2500, it would need to be 20 metres or more above the Atlantic waves.

“This dam is mainly a call to do something about climate change now. If we do nothing, then this extreme dam might just be the only solution”

The 160 kms (100 miles) of sea defence from south-west England to the westernmost point of France would be a little less problematic: sea depths are hardly more than 100 metres (330 feet).

But the engineers would also have to factor in the 40,000 cubic metres of river water that would discharge into this enclosed basin every second. This would mean the same volume would need pumping continuously into the Atlantic on the far side of the dikes.

Since the barrier would enclose a number of the world’s great shipping ports, there would have to be sluice gates to let the big ships through, or alternatively new ports on the ocean side of the barriers.

The very nature of the enclosed North Sea would begin to change. Within a decade or two, it would start to turn into a freshwater lake: it would be the end of centuries of a fishing industry.

It could – the scientists admit their calculations are of the “back of an envelope” variety – be done. They scaled up the costs of the world’s largest dikes so far in the Netherlands and South Korea, to calculate the 51 billion tonnes of sand needed for the project. This is about what the world uses every year in construction.

Technology tested

They note that fixed seabed oil platforms have been constructed to a depth of 500 metres (1,640 feet), so engineers already know how to do such things. Pumps of the scale required to handle the incoming river discharges are already in use, but they would be needed in their hundreds.

And although the cost would reach somewhere between €250-550 bn (£220-480 bn), this − spread over the 20 years the project would take − would represent only at most 0.32% of the gross domestic product of the UK, Netherlands, Germany, Belgium and Denmark combined: the five nations with most to lose from the rising tides.

It would, the authors argue, cost just the Netherlands – which already has 3,600 km (2,240 miles) of flood protection − a third of that sum to defend against sea level rises of only 1.5 metres. The good news is that, if such a project worked for western Europe, then the same techniques could enclose the Irish Sea, the Mediterranean, the Red Sea and the Persian Gulf.

“This dam makes it almost tangible what the consequences of continued sea level rise will be; a rise of 10 metres by the year 2500 according to the bleakest scenarios,” said Dr Groeskamp.

“This dam is therefore mainly a call to do something about climate change now. If we do nothing, then this extreme dam might just be the only solution.” − Climate News Network

Rising tides will leave no choice for US millions

Time and tide wait for no-one. As sea levels rise, the rising tides will become more impatient. Millions of Americans will have to migrate.

LONDON, 26 February, 2020 – The Texan city of Houston is about to grow in unexpected ways, thanks to the rising tides. So will Dallas. Real estate agents in Atlanta, Georgia; Denver, Colorado; and Las Vegas, Nevada could expect to do roaring business.

The inland counties around Los Angeles, and close to New Orleans in Louisiana, will suddenly get a little more crowded. And from Boston in the north-east to the tip of Florida, Americans will be on the move.

That is because an estimated 13 million US citizens could some time in this century become climate refugees, driven from their seaside homes by sea level rise of possibly 1.8 metres, according to new research.

And they will have to move home in a poorer economic climate: worldwide. If governments and city authorities do not take the right steps, sea level rise could erode 4% of the global annual economy, says a separate study. That is, coast-dwellers could witness not just their towns and even cities washed away: they could see their prosperity go under as well.

Californian scientists report in the Public Library of Science journal PLOS One that they used machine learning techniques – in effect, artificial intelligence systems – to calculate what is most likely to happen as US citizens desert Delaware Bay, slip away from the cities of North and South Carolina, and flee Florida in the face of rising sea levels, coastal flooding and increasingly catastrophic windstorms.

“Sea level rise will affect every county in the United States … everybody should care about sea level rise, whether they live on the coast or not”

In the year 2000, a third of all the planet’s urban land was in a zone vulnerable to flood. By 2040, this could rise to 40%. In 2010, in the US, more than 120m citizens – that is nearly 40% of the entire population – lived in coastal counties. By 2020, this proportion could already be higher.

And by 2100, at least 13.1m people could be living on land likely to be inundated if sea levels rise by 1.8 metres. Except that they won’t: they will have already seen the future and moved away from it, to some settlement well away from the rising tides.

Those who might otherwise have purchased their abandoned seaside houses will be looking for somewhere safer and adding to the pressure on the housing market.

“Sea level rise will affect every county in the United States,” said Bistra Dilkina of the University of Southern California at Irvine, a computer scientist who worked with engineers to model the human response to the future.

She and her colleagues started from patterns of movement that began with Hurricane Katrina, in 2004, and Hurricane Rita a year later, both in Louisiana. They then let the algorithms take over the challenge of guessing what American families and businesses are most likely to do as the tides begin to flood the high streets.

Action promised

“We hope this research will empower urban planners and local decision-makers to prepare to accept populations displaced by sea level rise. Our findings indicate that everybody should care about sea level rise, whether they live on the coast or not,” she said.

The California team’s worst-case forecasts are based on a premise that the world takes no real action to combat sea level rise, which is driven by global warming powered in turn by fossil fuel emissions into the atmosphere on an ever-increasing scale.

But in Paris in 2015, more than 190 nations did agree to act: to contain global warming to “well below” 2°C by the century’s end. So far, very few have committed to sufficient action, and the President of the US has pronounced climate change a “hoax” and announced a withdrawal from the Paris Agreement.

Researchers in Austria report in the journal Environmental Research Communications that they decided to consider the potential economic cost worldwide of sea level rise alone. Scientists have been trying for years to guess the cost of flood damage to come: the latest study is of the impact of sea level rise and coastal flooding upon national economies worldwide.

The scientists considered two scenarios, including one in which the world kept the promises made in Paris, and one in which it did not, and made no attempt to adapt to or mitigate climate change.

Significant impact

By 2050 losses in each scenario would be significant and much the same. But by 2100, the do-nothing option promised to hit the gross domestic product – an economist’s favourite measure of economic well-being – by 4%.

Europe and Japan would be significantly hit; China , India and Canada hardest of all. If the world’s richest nations actually worked to limit climate change and adapt to the challenges ahead, the impact on the economy could be limited to 1%.

“The findings of this paper demonstrate that we need to think long term while acting swiftly,” said Thomas Schinko of the International Institute for Applied Systems Analysis in Austria, who led the study.

“Macroeconomic impacts up to and beyond 2050 as a result of coastal flooding due to sea level rise – not taking into account any other climate-related impacts such as drought – are severe and increasing.

“We, as a global society, need to further co-ordinate mitigation, adaptation and climate-resilient development and consider where we build cities and situate important infrastructure.” – Climate News Network

Time and tide wait for no-one. As sea levels rise, the rising tides will become more impatient. Millions of Americans will have to migrate.

LONDON, 26 February, 2020 – The Texan city of Houston is about to grow in unexpected ways, thanks to the rising tides. So will Dallas. Real estate agents in Atlanta, Georgia; Denver, Colorado; and Las Vegas, Nevada could expect to do roaring business.

The inland counties around Los Angeles, and close to New Orleans in Louisiana, will suddenly get a little more crowded. And from Boston in the north-east to the tip of Florida, Americans will be on the move.

That is because an estimated 13 million US citizens could some time in this century become climate refugees, driven from their seaside homes by sea level rise of possibly 1.8 metres, according to new research.

And they will have to move home in a poorer economic climate: worldwide. If governments and city authorities do not take the right steps, sea level rise could erode 4% of the global annual economy, says a separate study. That is, coast-dwellers could witness not just their towns and even cities washed away: they could see their prosperity go under as well.

Californian scientists report in the Public Library of Science journal PLOS One that they used machine learning techniques – in effect, artificial intelligence systems – to calculate what is most likely to happen as US citizens desert Delaware Bay, slip away from the cities of North and South Carolina, and flee Florida in the face of rising sea levels, coastal flooding and increasingly catastrophic windstorms.

“Sea level rise will affect every county in the United States … everybody should care about sea level rise, whether they live on the coast or not”

In the year 2000, a third of all the planet’s urban land was in a zone vulnerable to flood. By 2040, this could rise to 40%. In 2010, in the US, more than 120m citizens – that is nearly 40% of the entire population – lived in coastal counties. By 2020, this proportion could already be higher.

And by 2100, at least 13.1m people could be living on land likely to be inundated if sea levels rise by 1.8 metres. Except that they won’t: they will have already seen the future and moved away from it, to some settlement well away from the rising tides.

Those who might otherwise have purchased their abandoned seaside houses will be looking for somewhere safer and adding to the pressure on the housing market.

“Sea level rise will affect every county in the United States,” said Bistra Dilkina of the University of Southern California at Irvine, a computer scientist who worked with engineers to model the human response to the future.

She and her colleagues started from patterns of movement that began with Hurricane Katrina, in 2004, and Hurricane Rita a year later, both in Louisiana. They then let the algorithms take over the challenge of guessing what American families and businesses are most likely to do as the tides begin to flood the high streets.

Action promised

“We hope this research will empower urban planners and local decision-makers to prepare to accept populations displaced by sea level rise. Our findings indicate that everybody should care about sea level rise, whether they live on the coast or not,” she said.

The California team’s worst-case forecasts are based on a premise that the world takes no real action to combat sea level rise, which is driven by global warming powered in turn by fossil fuel emissions into the atmosphere on an ever-increasing scale.

But in Paris in 2015, more than 190 nations did agree to act: to contain global warming to “well below” 2°C by the century’s end. So far, very few have committed to sufficient action, and the President of the US has pronounced climate change a “hoax” and announced a withdrawal from the Paris Agreement.

Researchers in Austria report in the journal Environmental Research Communications that they decided to consider the potential economic cost worldwide of sea level rise alone. Scientists have been trying for years to guess the cost of flood damage to come: the latest study is of the impact of sea level rise and coastal flooding upon national economies worldwide.

The scientists considered two scenarios, including one in which the world kept the promises made in Paris, and one in which it did not, and made no attempt to adapt to or mitigate climate change.

Significant impact

By 2050 losses in each scenario would be significant and much the same. But by 2100, the do-nothing option promised to hit the gross domestic product – an economist’s favourite measure of economic well-being – by 4%.

Europe and Japan would be significantly hit; China , India and Canada hardest of all. If the world’s richest nations actually worked to limit climate change and adapt to the challenges ahead, the impact on the economy could be limited to 1%.

“The findings of this paper demonstrate that we need to think long term while acting swiftly,” said Thomas Schinko of the International Institute for Applied Systems Analysis in Austria, who led the study.

“Macroeconomic impacts up to and beyond 2050 as a result of coastal flooding due to sea level rise – not taking into account any other climate-related impacts such as drought – are severe and increasing.

“We, as a global society, need to further co-ordinate mitigation, adaptation and climate-resilient development and consider where we build cities and situate important infrastructure.” – Climate News Network

Record Antarctic temperatures fuel sea level worry


Sea levels may threaten coastal cities sooner than expected, scientists say, as ice loss speeds up and Antarctic temperatures rise.

LONDON, 20 February, 2020 − Across the world, people now alive in coastal areas may face dangerously rising seas within their lifetimes, as record Antarctic temperatures and rapid melting of the continent’s ice drive global sea levels upwards.

Temperatures on the Antarctic Peninsula reached more than 20°C for the first time in history earlier this month, the Guardian reported: “The 20.75C logged by Brazilian scientists at Seymour Island on 9 February was almost a full degree higher than the previous record of 19.8C, taken on Signy Island in January 1982.”

The Antarctic Peninsula has warmed by almost 3°C since the start of the Industrial Revolution around 200 years ago − faster than almost anywhere else on Earth. But scientists are increasingly concerned not only about the Peninsula, but with the possibility that the entire southern continent may be heating up much faster than current estimates suggest.

Among evidence of increasing scientific effort to determine what is happening is a joint UK-US collaboration, due to report in 2023 on the chances of the collapse of the huge Thwaites glacier in West Antarctica, where from 1992 to 2017 the annual rate of ice loss rose threefold.

Big speed-up

Now a study by scientists co-ordinated by Germany’s Potsdam Institute for Climate Impact Research (PIK) says sea level rise caused by Antarctica’s ice loss could become a major risk for coastal protection in the near future.

After what they call “an exceptionally comprehensive comparison of state-of-the-art computer models from around the world”, they conclude that Antarctica alone could cause global sea level to rise by 2100 by up to three times more than it did in the last century.

“The ‘Antarctica Factor’ turns out to be the greatest risk, and also the greatest uncertainty, for sea levels around the globe,” says the lead author, Anders Levermann of PIK and Columbia University’s Lamont-Doherty Earth Observatory (LDEO) in New York.

“While we saw about 19 centimetres of sea level rise in the past 100 years, Antarctic ice loss could lead to up to 58 centimetres within this century”, he said.

“We know for certain that not stopping the burning of coal, oil and gas will drive up the risks for coastal metropolises from New York to Mumbai, Hamburg and Shanghai”

“Coastal planning cannot merely rely on the best guess. It requires a risk analysis. Our study provides exactly that. The sea level contribution of Antarctica is very likely not going to be more than 58 centimetres.”

Thermal expansion of the oceans by global warming and the melting of glaciers, which so far have been the most important factors in sea level rise, will add to the contribution from Antarctic ice loss, making the overall sea level rise risk even bigger. But the ‘Antarctica Factor’ is about to become the most important element, according to the study, published in the journal Earth System Dynamics.

The range of sea-level rise estimates the scientists have come up with is fairly large. Assuming that humanity keeps on emitting greenhouse gases as before, they say, the range they call “very likely” to describe the future is between 6 and 58 cms for this century.

If greenhouse gas emissions were reduced rapidly, it would be between 4 and 37 cms. Importantly, the difference between a business-as-usual scenario and one of emissions reductions becomes substantially greater as time passes.

More robust insights

Sixteen ice sheet modelling groups consisting of 36 researchers from 27 institutes contributed to the new study. A similar study six years ago had to rely on the output of only five ice sheet models.

“The more computer simulation models we use, all of them with slightly different dynamic representations of the Antarctic ice sheet, the wider the range of results that we yield − but also the more robust the insights that we gain”, said co-author Sophie Nowicki of the NASA Goddard Space Flight Center.

“There are still large uncertainties, but we are constantly improving our understanding of the largest ice sheet on Earth. Comparing model outputs is a forceful tool to provide society with the necessary information for rational decisions.”

Over the long term, the Antarctic ice sheet has the potential ultimately to raise sea levels by many tens of metres. “What we know for certain”, said Professor Levermann, “is that not stopping the burning of coal, oil and gas will drive up the risks for coastal metropolises from New York to Mumbai, Hamburg and Shanghai.” − Climate News Network


Sea levels may threaten coastal cities sooner than expected, scientists say, as ice loss speeds up and Antarctic temperatures rise.

LONDON, 20 February, 2020 − Across the world, people now alive in coastal areas may face dangerously rising seas within their lifetimes, as record Antarctic temperatures and rapid melting of the continent’s ice drive global sea levels upwards.

Temperatures on the Antarctic Peninsula reached more than 20°C for the first time in history earlier this month, the Guardian reported: “The 20.75C logged by Brazilian scientists at Seymour Island on 9 February was almost a full degree higher than the previous record of 19.8C, taken on Signy Island in January 1982.”

The Antarctic Peninsula has warmed by almost 3°C since the start of the Industrial Revolution around 200 years ago − faster than almost anywhere else on Earth. But scientists are increasingly concerned not only about the Peninsula, but with the possibility that the entire southern continent may be heating up much faster than current estimates suggest.

Among evidence of increasing scientific effort to determine what is happening is a joint UK-US collaboration, due to report in 2023 on the chances of the collapse of the huge Thwaites glacier in West Antarctica, where from 1992 to 2017 the annual rate of ice loss rose threefold.

Big speed-up

Now a study by scientists co-ordinated by Germany’s Potsdam Institute for Climate Impact Research (PIK) says sea level rise caused by Antarctica’s ice loss could become a major risk for coastal protection in the near future.

After what they call “an exceptionally comprehensive comparison of state-of-the-art computer models from around the world”, they conclude that Antarctica alone could cause global sea level to rise by 2100 by up to three times more than it did in the last century.

“The ‘Antarctica Factor’ turns out to be the greatest risk, and also the greatest uncertainty, for sea levels around the globe,” says the lead author, Anders Levermann of PIK and Columbia University’s Lamont-Doherty Earth Observatory (LDEO) in New York.

“While we saw about 19 centimetres of sea level rise in the past 100 years, Antarctic ice loss could lead to up to 58 centimetres within this century”, he said.

“We know for certain that not stopping the burning of coal, oil and gas will drive up the risks for coastal metropolises from New York to Mumbai, Hamburg and Shanghai”

“Coastal planning cannot merely rely on the best guess. It requires a risk analysis. Our study provides exactly that. The sea level contribution of Antarctica is very likely not going to be more than 58 centimetres.”

Thermal expansion of the oceans by global warming and the melting of glaciers, which so far have been the most important factors in sea level rise, will add to the contribution from Antarctic ice loss, making the overall sea level rise risk even bigger. But the ‘Antarctica Factor’ is about to become the most important element, according to the study, published in the journal Earth System Dynamics.

The range of sea-level rise estimates the scientists have come up with is fairly large. Assuming that humanity keeps on emitting greenhouse gases as before, they say, the range they call “very likely” to describe the future is between 6 and 58 cms for this century.

If greenhouse gas emissions were reduced rapidly, it would be between 4 and 37 cms. Importantly, the difference between a business-as-usual scenario and one of emissions reductions becomes substantially greater as time passes.

More robust insights

Sixteen ice sheet modelling groups consisting of 36 researchers from 27 institutes contributed to the new study. A similar study six years ago had to rely on the output of only five ice sheet models.

“The more computer simulation models we use, all of them with slightly different dynamic representations of the Antarctic ice sheet, the wider the range of results that we yield − but also the more robust the insights that we gain”, said co-author Sophie Nowicki of the NASA Goddard Space Flight Center.

“There are still large uncertainties, but we are constantly improving our understanding of the largest ice sheet on Earth. Comparing model outputs is a forceful tool to provide society with the necessary information for rational decisions.”

Over the long term, the Antarctic ice sheet has the potential ultimately to raise sea levels by many tens of metres. “What we know for certain”, said Professor Levermann, “is that not stopping the burning of coal, oil and gas will drive up the risks for coastal metropolises from New York to Mumbai, Hamburg and Shanghai.” − Climate News Network

Speeding sea level rise threatens nuclear plants

With sea level rise accelerating faster than thought, the risk is growing for coastal cities − and for nuclear power stations.

LONDON, 14 February, 2020 − The latest science shows how the pace of sea level rise is speeding up, fuelling fears that not only millions of homes will be under threat, but that vulnerable installations like docks and power plants will be overwhelmed by the waves.

New research using satellite data over a 30-year period shows that around the year 2000 sea level rise was 2mm a year, by 2010 it was 3mm and now it is at 4mm, with the pace of change still increasing.

The calculations were made by a research student, Tadea Veng, at the Technical University of Denmark, which has a special interest in Greenland, where the icecap is melting fast. That, combined with accelerating melting in Antarctica and further warming of the oceans, is raising sea levels across the globe.

The report coincides with a European Environment Agency (EEA) study whose maps show large areas of the shorelines of countries with coastlines on the North Sea will go under water unless heavily defended against sea level rise.

Based on the maps, newspapers like The Guardian in London have predicted that more than half of one key UK east coast provincial port − Hull − will be swamped. Ironically, Hull is the base for making giant wind turbine blades for use in the North Sea.

“It’s not just the height of the rise in sea level that is important for the protection of nuclear facilities, it’s also the likely increase in storm surges”

The argument about how much the sea level will rise this century has been raging in scientific circles since the 1990s. At the start, predictions of sea level rise took into account only two possible causes: the expansion of seawater as it warmed, and the melting of mountain glaciers away from the poles.

In the early Intergovernmental Panel on Climate Change reports back then, the melting of the polar ice caps was not included, because scientists could not agree whether greater snowfall on the top of the ice caps in winter might balance out summer melting. Many of them also thought Antarctica would not melt at all, or not for centuries, because it was too cold.

Both the extra snow theory and the “too cold to melt” idea have now been discounted. In Antarctica this is partly because the sea has warmed up so much that it is melting the glaciers’ ice from beneath – something the scientists had not foreseen.

Alarm about sea level rise elsewhere has been increasing outside the scientific community, partly because many nuclear power plants are on coasts. Even those that are nearing the end of their working lives will be radio-active for another century, and many have highly dangerous spent fuel on site in storage ponds with no disposal route organised.

Perhaps most alarmed are British residents, whose government is currently planning a number of new seaside nuclear stations in low-lying coastal areas. Some will be under water this century according to the EEA, particularly one planned for Sizewell in eastern England.

Hard to tell

The Agency’s report says estimates of sea level rise by 2100 vary, with an upper limit of one metre generally accepted, but up to 2.5 metres predicted by some scientists. The latest research by Danish scientists suggests judiciously that with the speed of sea level rise continuing to accelerate, it is impossible to be sure.

A report by campaigners who oppose building nuclear power stations on Britain’s vulnerable coast expresses extreme alarm, saying both nuclear regulators and the giant French energy company EDF are too complacent about the problem.

The report says: “Polar ice caps appear to be melting faster than expected, and what is particularly worrying is that the rate of melting seems to be increasing. Some researchers say sea levels could rise by as much as six metres or more by 2100, even if the 2°C Paris targethttps://unfccc.int/process-and-meetings/the-paris-agreement/the-paris-agreement is met.

“But it’s not just the height of the rise in sea level that is important for the protection of nuclear facilities, it’s also the likely increase in storm surges. An increase in sea level of 50cm would mean the storm that used to come every thousand years will now come every 100 years. If you increase that to a metre, then that millennial storm is likely to come once a decade.

“Bearing in mind that there will probably be nuclear waste on the Hinkley Point C site [home to the new twin reactors being built by EDF in the West of England] until at least 2150, the question neither the Office of Nuclear Regulation nor EDF seem to be asking is whether further flood protection measures can be put in place fast enough to deal with unexpected and unpredicted storm surges.” − Climate News Network

With sea level rise accelerating faster than thought, the risk is growing for coastal cities − and for nuclear power stations.

LONDON, 14 February, 2020 − The latest science shows how the pace of sea level rise is speeding up, fuelling fears that not only millions of homes will be under threat, but that vulnerable installations like docks and power plants will be overwhelmed by the waves.

New research using satellite data over a 30-year period shows that around the year 2000 sea level rise was 2mm a year, by 2010 it was 3mm and now it is at 4mm, with the pace of change still increasing.

The calculations were made by a research student, Tadea Veng, at the Technical University of Denmark, which has a special interest in Greenland, where the icecap is melting fast. That, combined with accelerating melting in Antarctica and further warming of the oceans, is raising sea levels across the globe.

The report coincides with a European Environment Agency (EEA) study whose maps show large areas of the shorelines of countries with coastlines on the North Sea will go under water unless heavily defended against sea level rise.

Based on the maps, newspapers like The Guardian in London have predicted that more than half of one key UK east coast provincial port − Hull − will be swamped. Ironically, Hull is the base for making giant wind turbine blades for use in the North Sea.

“It’s not just the height of the rise in sea level that is important for the protection of nuclear facilities, it’s also the likely increase in storm surges”

The argument about how much the sea level will rise this century has been raging in scientific circles since the 1990s. At the start, predictions of sea level rise took into account only two possible causes: the expansion of seawater as it warmed, and the melting of mountain glaciers away from the poles.

In the early Intergovernmental Panel on Climate Change reports back then, the melting of the polar ice caps was not included, because scientists could not agree whether greater snowfall on the top of the ice caps in winter might balance out summer melting. Many of them also thought Antarctica would not melt at all, or not for centuries, because it was too cold.

Both the extra snow theory and the “too cold to melt” idea have now been discounted. In Antarctica this is partly because the sea has warmed up so much that it is melting the glaciers’ ice from beneath – something the scientists had not foreseen.

Alarm about sea level rise elsewhere has been increasing outside the scientific community, partly because many nuclear power plants are on coasts. Even those that are nearing the end of their working lives will be radio-active for another century, and many have highly dangerous spent fuel on site in storage ponds with no disposal route organised.

Perhaps most alarmed are British residents, whose government is currently planning a number of new seaside nuclear stations in low-lying coastal areas. Some will be under water this century according to the EEA, particularly one planned for Sizewell in eastern England.

Hard to tell

The Agency’s report says estimates of sea level rise by 2100 vary, with an upper limit of one metre generally accepted, but up to 2.5 metres predicted by some scientists. The latest research by Danish scientists suggests judiciously that with the speed of sea level rise continuing to accelerate, it is impossible to be sure.

A report by campaigners who oppose building nuclear power stations on Britain’s vulnerable coast expresses extreme alarm, saying both nuclear regulators and the giant French energy company EDF are too complacent about the problem.

The report says: “Polar ice caps appear to be melting faster than expected, and what is particularly worrying is that the rate of melting seems to be increasing. Some researchers say sea levels could rise by as much as six metres or more by 2100, even if the 2°C Paris targethttps://unfccc.int/process-and-meetings/the-paris-agreement/the-paris-agreement is met.

“But it’s not just the height of the rise in sea level that is important for the protection of nuclear facilities, it’s also the likely increase in storm surges. An increase in sea level of 50cm would mean the storm that used to come every thousand years will now come every 100 years. If you increase that to a metre, then that millennial storm is likely to come once a decade.

“Bearing in mind that there will probably be nuclear waste on the Hinkley Point C site [home to the new twin reactors being built by EDF in the West of England] until at least 2150, the question neither the Office of Nuclear Regulation nor EDF seem to be asking is whether further flood protection measures can be put in place fast enough to deal with unexpected and unpredicted storm surges.” − Climate News Network

Little time left to arrest Greenland’s melting

Humans may still have time to stop Greenland’s melting, preventing Arctic ice sheet collapse and devastating sea level rise. But the time left may be short.

LONDON, 30 December, 2019 – It’s still possible, but it’s far from certain: stopping Greenland’s melting can be done, but it must be done soon.

Norwegian and US scientists have taken a close look at the ice age history of Greenland and come to a grim conclusion. All it takes to set the island’s ice cap melting away is a mean sea surface temperature higher than seven degrees Celsius. And the present mean sea surface temperature is already 7.7°C.

Greenland is the northern hemisphere’s single richest store of frozen water: the island’s bedrock holds enough to raise global sea levels by seven metres and drown or wash away the world’s coastal communities, including the great cities of New York and Miami, Shanghai and Kolkata, Amsterdam and London.

And the pattern of geological evidence – outlined in the Proceedings of the National Academy of Sciences – combined with climate models suggests that any sustained temperature rise could trigger an irreversible melt of the entire southern Greenland ice sheet.

The scientists suggest that the threshold for this calamity could be between 0.8°C above the post-Ice Age norm, and 3.2°C.

“The critical temperature threshold for past Greenland ice sheet decay will likely be surpassed this century”

In fact, because of profligate use of fossil fuels and the release of greenhouse gases into the atmosphere, the planet has already warmed by around 1°C above the level for most of human history, and warming of at least 3.2°C by the end of this century now seems almost certain.

Researchers publish their conclusions with the intention that they should be examined, tested, challenged and perhaps overturned. But widespread alarm at the rate of melt and mass loss in Greenland has been consistent and increasing with the years.

Researchers have repeatedly established that melting each summer is increasing the rate at which glaciers flow and deliver ice to increasingly warmer northern seas, and that this rate of melting has itself begun to accelerate.

So Nil Irvali of the University of Bergen and colleagues took a closer look at the story told by microfossils within cores from the ice and the ocean floor during four interglacial periods over the last 450,000 years.

During those warm spells ocean levels rose dramatically, and in two episodes Greenland’s vanishing ice could have contributed more than five metres in one case, and up to seven metres of sea level rise in the other.

Triggers identified

And in all four of those interglacials, conditions reached temperatures higher than they are right now.

Concern about the stability of the Greenland icecap is no surprise: the Arctic is already warming faster than anywhere else on the planet, thanks to profligate use of fossil fuels and the destruction of the rainforests, and researchers worldwide have begun to identify triggers that feed back into further warming: rain, for instance, in winter; the loss of cloud cover in summer; and the deposits of soot from polar wildfires that darken the snows and enhance the absorption of the sun’s rays.

Years ago, the phrase “at a glacial pace” ceased to be a valid cliché: US scientists clocked one river of ice moving at a rate of 46 metres a day.

So the new study simply confirms fears that already are widespread. What remains to be settled is the point at which the decline of the ice sheet becomes irreversible, the Bergen scientists say. As the ocean warms, this feeds back into the process of melting and triggers longer-term feedbacks.

“The exact point at which these feedbacks are triggered remains equivocal,” say Dr Irvali and her co-authors. “Notably, the critical temperature threshold for past Greenland ice sheet decay will likely be surpassed this century. The duration for which this threshold is exceeded will determine Greenland’s fate.” – Climate News Network

Humans may still have time to stop Greenland’s melting, preventing Arctic ice sheet collapse and devastating sea level rise. But the time left may be short.

LONDON, 30 December, 2019 – It’s still possible, but it’s far from certain: stopping Greenland’s melting can be done, but it must be done soon.

Norwegian and US scientists have taken a close look at the ice age history of Greenland and come to a grim conclusion. All it takes to set the island’s ice cap melting away is a mean sea surface temperature higher than seven degrees Celsius. And the present mean sea surface temperature is already 7.7°C.

Greenland is the northern hemisphere’s single richest store of frozen water: the island’s bedrock holds enough to raise global sea levels by seven metres and drown or wash away the world’s coastal communities, including the great cities of New York and Miami, Shanghai and Kolkata, Amsterdam and London.

And the pattern of geological evidence – outlined in the Proceedings of the National Academy of Sciences – combined with climate models suggests that any sustained temperature rise could trigger an irreversible melt of the entire southern Greenland ice sheet.

The scientists suggest that the threshold for this calamity could be between 0.8°C above the post-Ice Age norm, and 3.2°C.

“The critical temperature threshold for past Greenland ice sheet decay will likely be surpassed this century”

In fact, because of profligate use of fossil fuels and the release of greenhouse gases into the atmosphere, the planet has already warmed by around 1°C above the level for most of human history, and warming of at least 3.2°C by the end of this century now seems almost certain.

Researchers publish their conclusions with the intention that they should be examined, tested, challenged and perhaps overturned. But widespread alarm at the rate of melt and mass loss in Greenland has been consistent and increasing with the years.

Researchers have repeatedly established that melting each summer is increasing the rate at which glaciers flow and deliver ice to increasingly warmer northern seas, and that this rate of melting has itself begun to accelerate.

So Nil Irvali of the University of Bergen and colleagues took a closer look at the story told by microfossils within cores from the ice and the ocean floor during four interglacial periods over the last 450,000 years.

During those warm spells ocean levels rose dramatically, and in two episodes Greenland’s vanishing ice could have contributed more than five metres in one case, and up to seven metres of sea level rise in the other.

Triggers identified

And in all four of those interglacials, conditions reached temperatures higher than they are right now.

Concern about the stability of the Greenland icecap is no surprise: the Arctic is already warming faster than anywhere else on the planet, thanks to profligate use of fossil fuels and the destruction of the rainforests, and researchers worldwide have begun to identify triggers that feed back into further warming: rain, for instance, in winter; the loss of cloud cover in summer; and the deposits of soot from polar wildfires that darken the snows and enhance the absorption of the sun’s rays.

Years ago, the phrase “at a glacial pace” ceased to be a valid cliché: US scientists clocked one river of ice moving at a rate of 46 metres a day.

So the new study simply confirms fears that already are widespread. What remains to be settled is the point at which the decline of the ice sheet becomes irreversible, the Bergen scientists say. As the ocean warms, this feeds back into the process of melting and triggers longer-term feedbacks.

“The exact point at which these feedbacks are triggered remains equivocal,” say Dr Irvali and her co-authors. “Notably, the critical temperature threshold for past Greenland ice sheet decay will likely be surpassed this century. The duration for which this threshold is exceeded will determine Greenland’s fate.” – Climate News Network

Heat the Arctic to cool the Earth, scientists say

If we seriously want to tackle the climate crisis, here’s a drastic idea: we could heat the Arctic to cool the planet.

LONDON, 19 December, 2019 − With politicians failing to cut greenhouse gas emissions far and fast enough, the only hope may be to find a different way to cool the planet. One group of researchers has put forward an idea so different that critics may regard it as outlandish: heat the Arctic.

To heat the Arctic so much that the sea ice disappears even in the winter sounds like a weird idea. But the researchers believe it would have the beneficial effect of cooling the planet down.

They argue that with the Arctic ice already expected to disappear during the summer months within the next 30 years, and large increases in temperature and changes in the polar climate already certain, we should turn this radical shift to our advantage.

Their point is that since, at the current rate of progress, politicians seem unlikely to cut greenhouse gas emissions enough to prevent drastic temperature rise, humankind must find other ways to cool the Earth if it is to survive.

“Climate change is a major issue and all options should be considered when dealing with it”

Heating the planet in order to cool it is certainly counter-intuitive. But, whether or not the scheme could ever work, it shows the ingenuity and enterprise now being poured into stabilising global temperatures close to their historic level.

It also, of course, shows how horribly late we have left it to rein in the climate crisis, when wise and determined action 30 years ago could have achieved so much.

The idea proposed is, in principle, simple enough: to ensure that the warm currents of the Gulf Stream, known by science as the North Atlantic Oscillation (NAO) continue northwards across the Arctic Circle the whole year round. This would release massive amounts of heat from the ocean into the atmosphere and beyond that into space, so cooling the sea and ultimately the Earth.

“The Arctic Ocean ice cover works as a strong insulator, impeding the heat from the ocean below to warm up the atmosphere above. If this ice layer were however removed, the atmosphere would increase in temperature by around 20°C during the winter.

More heat escapes

“This increase in temperature would in turn increase the heat irradiated into space, thus cooling down the oceans,” explains the lead author of the study which details the proposal, published in the journal SN Applied Sciences. He is Julian Hunt, a postdoctoral research scholar at IIASA, the International Institute for Applied Systems Analysis.

The problem that needs to be overcome is that very cold and only mildly salty water currently floats on the surface of the Arctic Ocean, freezing in the winter and capturing the warmth of the water in the ocean depths.

The authors say the main factor helping to maintain the Arctic sea ice cover is the fact that the top 100 metres of the ocean is less saline than the Atlantic, preventing the Atlantic from flowing above the cold Arctic waters. Increasing the salinity of the Arctic Ocean’s surface, they say, would let the warmer and less salty North Atlantic current flow over it, warming the atmosphere considerably and releasing the ocean heat trapped under the ice.

They suggest three ways to keep fresh water out of the Arctic. The first would divert the big rivers of North America and Siberia southwards to prevent them draining into the polar ocean. The second would place submerged obstructions in front of the rapidly melting Greenland glaciers, to slow the speed of the ice sheets’ melting, while the third would use a solar- and wind-powered icebreaker to pump cold, near-fresh water deeper into the ocean to mix with the saltier water below, allowing the warmer currents to sweep in from the south.

Unknown consequences

Dr Hunt and his colleagues say there could be terrific benefits. Shipping could navigate the ice-free Arctic Ocean all year round, cutting journey times between Asia, Europe and North America. The need for heating homes in the northern hemisphere during the winter would be drastically reduced, because their plan would raise air temperatures by as much as 20°C.

But the massive interference with natural systems in the Arctic would also have its downside. The rapid year-round rise in temperature would dramatically increase the melting of Greenland and therefore of sea level rise the world over. The effect on the northern hemisphere climate, particularly much increased rainfall with a warmer sea and atmosphere, is impossible to predict.

But Dr Hunt says that while there are clearly huge risks, the world is already heading for uncharted waters, so humans must do something drastic. “Although it is important to mitigate the impacts from climate change with the reduction in CO2 emissions, we should also think of ways to adapt the world to the new climate conditions to avoid uncontrollable, unpredictable and destructive climate change resulting in socio-economic and environmental collapse.

“Climate change is a major issue and all options should be considered when dealing with it.” − Climate News Network

If we seriously want to tackle the climate crisis, here’s a drastic idea: we could heat the Arctic to cool the planet.

LONDON, 19 December, 2019 − With politicians failing to cut greenhouse gas emissions far and fast enough, the only hope may be to find a different way to cool the planet. One group of researchers has put forward an idea so different that critics may regard it as outlandish: heat the Arctic.

To heat the Arctic so much that the sea ice disappears even in the winter sounds like a weird idea. But the researchers believe it would have the beneficial effect of cooling the planet down.

They argue that with the Arctic ice already expected to disappear during the summer months within the next 30 years, and large increases in temperature and changes in the polar climate already certain, we should turn this radical shift to our advantage.

Their point is that since, at the current rate of progress, politicians seem unlikely to cut greenhouse gas emissions enough to prevent drastic temperature rise, humankind must find other ways to cool the Earth if it is to survive.

“Climate change is a major issue and all options should be considered when dealing with it”

Heating the planet in order to cool it is certainly counter-intuitive. But, whether or not the scheme could ever work, it shows the ingenuity and enterprise now being poured into stabilising global temperatures close to their historic level.

It also, of course, shows how horribly late we have left it to rein in the climate crisis, when wise and determined action 30 years ago could have achieved so much.

The idea proposed is, in principle, simple enough: to ensure that the warm currents of the Gulf Stream, known by science as the North Atlantic Oscillation (NAO) continue northwards across the Arctic Circle the whole year round. This would release massive amounts of heat from the ocean into the atmosphere and beyond that into space, so cooling the sea and ultimately the Earth.

“The Arctic Ocean ice cover works as a strong insulator, impeding the heat from the ocean below to warm up the atmosphere above. If this ice layer were however removed, the atmosphere would increase in temperature by around 20°C during the winter.

More heat escapes

“This increase in temperature would in turn increase the heat irradiated into space, thus cooling down the oceans,” explains the lead author of the study which details the proposal, published in the journal SN Applied Sciences. He is Julian Hunt, a postdoctoral research scholar at IIASA, the International Institute for Applied Systems Analysis.

The problem that needs to be overcome is that very cold and only mildly salty water currently floats on the surface of the Arctic Ocean, freezing in the winter and capturing the warmth of the water in the ocean depths.

The authors say the main factor helping to maintain the Arctic sea ice cover is the fact that the top 100 metres of the ocean is less saline than the Atlantic, preventing the Atlantic from flowing above the cold Arctic waters. Increasing the salinity of the Arctic Ocean’s surface, they say, would let the warmer and less salty North Atlantic current flow over it, warming the atmosphere considerably and releasing the ocean heat trapped under the ice.

They suggest three ways to keep fresh water out of the Arctic. The first would divert the big rivers of North America and Siberia southwards to prevent them draining into the polar ocean. The second would place submerged obstructions in front of the rapidly melting Greenland glaciers, to slow the speed of the ice sheets’ melting, while the third would use a solar- and wind-powered icebreaker to pump cold, near-fresh water deeper into the ocean to mix with the saltier water below, allowing the warmer currents to sweep in from the south.

Unknown consequences

Dr Hunt and his colleagues say there could be terrific benefits. Shipping could navigate the ice-free Arctic Ocean all year round, cutting journey times between Asia, Europe and North America. The need for heating homes in the northern hemisphere during the winter would be drastically reduced, because their plan would raise air temperatures by as much as 20°C.

But the massive interference with natural systems in the Arctic would also have its downside. The rapid year-round rise in temperature would dramatically increase the melting of Greenland and therefore of sea level rise the world over. The effect on the northern hemisphere climate, particularly much increased rainfall with a warmer sea and atmosphere, is impossible to predict.

But Dr Hunt says that while there are clearly huge risks, the world is already heading for uncharted waters, so humans must do something drastic. “Although it is important to mitigate the impacts from climate change with the reduction in CO2 emissions, we should also think of ways to adapt the world to the new climate conditions to avoid uncontrollable, unpredictable and destructive climate change resulting in socio-economic and environmental collapse.

“Climate change is a major issue and all options should be considered when dealing with it.” − Climate News Network

Greenland ice melt feeds glacier instability

In a runaway effect, the Greenland ice melt lets surface water gurgle down to the bedrock – and at unexpected speeds.

LONDON, 6 December, 2019 – British scientists have caught a huge ice sheet in the act of draining away, with significant effects on its surroundings: they have seen what happens to the water created by the Greenland ice melt.

For the first time – and with help from drones – researchers have witnessed water flowing at a million cubic metres an hour from the surface of ice sheets through caverns in the ice and down to the glacial bedrock.

The study does not change the big picture of increasingly rapid melt as greenhouse gases build up in the atmosphere, and ever more of the northern hemisphere’s biggest ice cap flows downhill to raise global sea levels.

But it does throw light on the mechanisms by which glaciers turn to sea water, and it does suggest that many estimates of melt rate so far might prove to be under-estimates.

Greenland is the planet’s second largest ice sheet and the biggest single contributor to global sea level rise. Researchers have been alarmed for years about the increasing rate of summer melt and the accelerating speed of what had once been imperceptible glacial flows.

“These glaciers are already moving quite fast, so the effect of the lakes may not appear as dramatic as on slower-moving glaciers elsewhere, but the overall effect is in fact very significant”

And researchers from the universities of Cambridge, Aberystwyth and Lancaster have now been able to put a measure on water surface loss.

They report in the Proceedings of the National Academy of Sciences that they used custom-built aerial drones and complex computer modelling to work out how fractures form below vast lakes of meltwater that collect on the surface of the Store Glacier on the island’s northwestern sheet.

They watched splits form in the glacial ice, to suddenly open up an escape route for the supraglacial pool. As they watched, such fractures became caverns called moulins, down which in one case five million cubic metres of water – think of 2,000 Olympic swimming pools – flowed in just five hours.

The ice of the glacier is typically a kilometre thick, so the scientists may have observed the planet’s longest waterfall. And as the ice drained away to the bottom of the ice sheet, it may have served as a lubricant to speed up glacier flow over the bedrock.

The ice sheet lifted by half a metre, presumably in response to the sub-surface flood, and four kilometres downstream glacial speed picked up from a speed of two metres to more than five metres a day.

Daily billion-tonne loss

“It’s possible we’ve under-estimated the effects of these glaciers on the overall instability of the Greenland ice sheet. It’s a rare thing to observe these fast-draining lakes – we were lucky to be in the right place at the right time,” said Tom Chudley, of the Scott Polar Research Institute in Cambridge, one of the authors.

Until now, scientists have been able to estimate glacial flow and surface melt only by satellite studies – which reveal little of the detail – or direct on-the-ground measurement under conditions that are difficult even in good weather.

But even with these constraints researchers have been able to calculate the shrinkage of the Greenland ice sheet at the rate of a billion tonnes a day, as temperatures rise in response to ever-increasing use of fossil fuels around the globe.

The next step is to deploy drilling equipment for a closer look at how the water gets below the glacier to reach the bedrock, and calculate how the ice sheet may change not just over hours but over the coming decades as well.

“These glaciers are already moving quite fast, so the effect of the lakes may not appear as dramatic as on slower-moving glaciers elsewhere,” said Poul Christofferson, who led the project, “but the overall effect is in fact very significant.” – Climate News Network

In a runaway effect, the Greenland ice melt lets surface water gurgle down to the bedrock – and at unexpected speeds.

LONDON, 6 December, 2019 – British scientists have caught a huge ice sheet in the act of draining away, with significant effects on its surroundings: they have seen what happens to the water created by the Greenland ice melt.

For the first time – and with help from drones – researchers have witnessed water flowing at a million cubic metres an hour from the surface of ice sheets through caverns in the ice and down to the glacial bedrock.

The study does not change the big picture of increasingly rapid melt as greenhouse gases build up in the atmosphere, and ever more of the northern hemisphere’s biggest ice cap flows downhill to raise global sea levels.

But it does throw light on the mechanisms by which glaciers turn to sea water, and it does suggest that many estimates of melt rate so far might prove to be under-estimates.

Greenland is the planet’s second largest ice sheet and the biggest single contributor to global sea level rise. Researchers have been alarmed for years about the increasing rate of summer melt and the accelerating speed of what had once been imperceptible glacial flows.

“These glaciers are already moving quite fast, so the effect of the lakes may not appear as dramatic as on slower-moving glaciers elsewhere, but the overall effect is in fact very significant”

And researchers from the universities of Cambridge, Aberystwyth and Lancaster have now been able to put a measure on water surface loss.

They report in the Proceedings of the National Academy of Sciences that they used custom-built aerial drones and complex computer modelling to work out how fractures form below vast lakes of meltwater that collect on the surface of the Store Glacier on the island’s northwestern sheet.

They watched splits form in the glacial ice, to suddenly open up an escape route for the supraglacial pool. As they watched, such fractures became caverns called moulins, down which in one case five million cubic metres of water – think of 2,000 Olympic swimming pools – flowed in just five hours.

The ice of the glacier is typically a kilometre thick, so the scientists may have observed the planet’s longest waterfall. And as the ice drained away to the bottom of the ice sheet, it may have served as a lubricant to speed up glacier flow over the bedrock.

The ice sheet lifted by half a metre, presumably in response to the sub-surface flood, and four kilometres downstream glacial speed picked up from a speed of two metres to more than five metres a day.

Daily billion-tonne loss

“It’s possible we’ve under-estimated the effects of these glaciers on the overall instability of the Greenland ice sheet. It’s a rare thing to observe these fast-draining lakes – we were lucky to be in the right place at the right time,” said Tom Chudley, of the Scott Polar Research Institute in Cambridge, one of the authors.

Until now, scientists have been able to estimate glacial flow and surface melt only by satellite studies – which reveal little of the detail – or direct on-the-ground measurement under conditions that are difficult even in good weather.

But even with these constraints researchers have been able to calculate the shrinkage of the Greenland ice sheet at the rate of a billion tonnes a day, as temperatures rise in response to ever-increasing use of fossil fuels around the globe.

The next step is to deploy drilling equipment for a closer look at how the water gets below the glacier to reach the bedrock, and calculate how the ice sheet may change not just over hours but over the coming decades as well.

“These glaciers are already moving quite fast, so the effect of the lakes may not appear as dramatic as on slower-moving glaciers elsewhere,” said Poul Christofferson, who led the project, “but the overall effect is in fact very significant.” – Climate News Network

Earth nears irreversible tipping points

Changes afoot now in at least nine areas could drastically alter the Earth’s climate. There’s no time left to act on these tipping points.

LONDON, 28 November, 2019 – On the eve of a global climate summit in Madrid, seven distinguished climate scientists have issued an urgent warning of approaching planetary tipping points: within a few years, they say, humankind could enter a state of potentially catastrophic climate change on a new “hothouse” Earth.

They warn that dramatic changes to planetary stability may already be happening in nine vulnerable ecosystems. As these changes happen, they could reinforce each other and at the same time amplify planetary temperature rise, commit the oceans to inexorable sea level rise of around 10 metres, and threaten the existence of human civilisations.

Their warning is issued in a commentary in the journal Nature. Their conclusions are not – and perhaps cannot be – confirmed by direct evidence or the consensus of other scientists. They present an opinion, not a set of facts that can be scrutinised and challenged or endorsed by their peers.

And the seven researchers recognise that although such changes are happening at speed, some of the consequences of those changes will follow more slowly. Their point is that the risks of irreversible change are too great not to act – and to act now.

Happening now

But the fact that they have chosen to issue such an alarm at all is a measure of the concern raised by the rapid retreat of the Arctic ice, the steady loss of the Greenland ice cap, the damage to the boreal forests, the thaw of the polar permafrost, the slowing of a great ocean current, the loss of tropical corals and the collapse of ice sheets in East and West Antarctica.

Each of these happenings – and many more – was identified more than a decade ago as a potential “tipping point”: an irreversible change that would amplify global heating and trigger a cascade of other climate changes.

“Now we see evidence that over half of them have been activated,” said Tim Lenton of the University of Exeter, UK. “The growing threat of rapid, irreversible changes means it is no longer responsible to wait and see.”

“The stability and resilience of our planet is in peril. International action – not just words – must reflect this”

The idea of a climate tipping point – a threshold beyond which dramatic climate change would be irreversible – is an old one. Two decades ago the Intergovernmental Panel on Climate Change examined the idea and proposed that, were the planet to warm by 5°C above the long-term average for most of human history, then it could tip into a new climate regime.

But in the last few decades, carbon dioxide concentrations in the atmosphere have gone from around 280 parts per million to more than 400 ppm, and global average temperatures have risen by more than 1°C. And the rate of change, driven by profligate use of fossil fuels that deposit greenhouse gases into the atmosphere, has been alarming.

“It is not only human pressures on Earth that continue rising to unprecedented levels. It is also that, as science advances, we must admit that we have underestimated the risks of unleashing irreversible changes, where the planet self-amplifies global warming. This is what we are seeing already at 1°C global warming,” said Johan Rockström, who directs the Potsdam Institute for Climate Impact Research in Germany, and who is another signatory.

“Scientifically, this provides strong evidence for declaring a state of planetary emergency, to unleash world action that accelerates the path towards a world that can continue evolving on a stable planet.”

Inadequate pledges

In 2015, at a climate summit in Paris, 195 nations promised to contain planetary heating to “well below” 2°C, and ideally to 1.5°C, by 2100. But the Nature signatories point at that even if the pledges those nations made are implemented – a “big if”, they warn – then they will ensure only that the world is committed to at least 3°C warming.

The scientists believe there is still time to act – but their dangerous tipping points are now dangerously close.

The arguments go like this. In West Antarctica, ice may already be retreating beyond the “grounding line” where ice, ocean and bedrock meet. If so, then the rest of the West Antarctic ice sheet could collapse, and sea levels could rise by three metres.

New evidence suggests the East Antarctic ice sheet could be similarly unstable, and precipitate further sea level rise of up to four metres. Hundreds of millions are already at risk from coastal flooding.

Timescale controlled

The Greenland ice sheet is melting at an accelerating rate, and once past a critical threshold could lose enough water to raise sea levels by seven metres. Even a 1.5°C warming might condemn Greenland to irreversible melting – and on present form the world could warm by 1.5°C by 2030.

“Thus we might have already committed future generations to living with sea level rises of around 10m over thousands of years. But the timescale is still under our control,” the authors warn.

They also warn that a “staggering 99% of tropical corals” could be lost if the planet heats by even 2°C – at a profound cost to both marine sea life and human economies.

They say 17% of the Amazon rainforest has been lost since 1970: a loss of somewhere between 20% and 40% could tip the entire rainforest into a destabilised state, increasingly at risk from drought and fire.

Risks multiply

In the boreal forests of northern Asia, Europe and Canada, insect outbreaks, fire and dieback could turn some regions into sources of more carbon, rather than sinks that soak up the extra carbon dioxide.

Permafrost thaw could release ever-greater volumes of stored methane, a greenhouse gas 30 times more potent, over a century, than carbon dioxide, and so on. The dangers multiply, and each one amplifies planetary heating.

“If damaging tipping cascades can occur and a global tipping point cannot be ruled out, then this is an existential threat to civilisation,” the authors warn.

“The stability and resilience of our planet is in peril. International action – not just words – must reflect this.” – Climate News Network

Changes afoot now in at least nine areas could drastically alter the Earth’s climate. There’s no time left to act on these tipping points.

LONDON, 28 November, 2019 – On the eve of a global climate summit in Madrid, seven distinguished climate scientists have issued an urgent warning of approaching planetary tipping points: within a few years, they say, humankind could enter a state of potentially catastrophic climate change on a new “hothouse” Earth.

They warn that dramatic changes to planetary stability may already be happening in nine vulnerable ecosystems. As these changes happen, they could reinforce each other and at the same time amplify planetary temperature rise, commit the oceans to inexorable sea level rise of around 10 metres, and threaten the existence of human civilisations.

Their warning is issued in a commentary in the journal Nature. Their conclusions are not – and perhaps cannot be – confirmed by direct evidence or the consensus of other scientists. They present an opinion, not a set of facts that can be scrutinised and challenged or endorsed by their peers.

And the seven researchers recognise that although such changes are happening at speed, some of the consequences of those changes will follow more slowly. Their point is that the risks of irreversible change are too great not to act – and to act now.

Happening now

But the fact that they have chosen to issue such an alarm at all is a measure of the concern raised by the rapid retreat of the Arctic ice, the steady loss of the Greenland ice cap, the damage to the boreal forests, the thaw of the polar permafrost, the slowing of a great ocean current, the loss of tropical corals and the collapse of ice sheets in East and West Antarctica.

Each of these happenings – and many more – was identified more than a decade ago as a potential “tipping point”: an irreversible change that would amplify global heating and trigger a cascade of other climate changes.

“Now we see evidence that over half of them have been activated,” said Tim Lenton of the University of Exeter, UK. “The growing threat of rapid, irreversible changes means it is no longer responsible to wait and see.”

“The stability and resilience of our planet is in peril. International action – not just words – must reflect this”

The idea of a climate tipping point – a threshold beyond which dramatic climate change would be irreversible – is an old one. Two decades ago the Intergovernmental Panel on Climate Change examined the idea and proposed that, were the planet to warm by 5°C above the long-term average for most of human history, then it could tip into a new climate regime.

But in the last few decades, carbon dioxide concentrations in the atmosphere have gone from around 280 parts per million to more than 400 ppm, and global average temperatures have risen by more than 1°C. And the rate of change, driven by profligate use of fossil fuels that deposit greenhouse gases into the atmosphere, has been alarming.

“It is not only human pressures on Earth that continue rising to unprecedented levels. It is also that, as science advances, we must admit that we have underestimated the risks of unleashing irreversible changes, where the planet self-amplifies global warming. This is what we are seeing already at 1°C global warming,” said Johan Rockström, who directs the Potsdam Institute for Climate Impact Research in Germany, and who is another signatory.

“Scientifically, this provides strong evidence for declaring a state of planetary emergency, to unleash world action that accelerates the path towards a world that can continue evolving on a stable planet.”

Inadequate pledges

In 2015, at a climate summit in Paris, 195 nations promised to contain planetary heating to “well below” 2°C, and ideally to 1.5°C, by 2100. But the Nature signatories point at that even if the pledges those nations made are implemented – a “big if”, they warn – then they will ensure only that the world is committed to at least 3°C warming.

The scientists believe there is still time to act – but their dangerous tipping points are now dangerously close.

The arguments go like this. In West Antarctica, ice may already be retreating beyond the “grounding line” where ice, ocean and bedrock meet. If so, then the rest of the West Antarctic ice sheet could collapse, and sea levels could rise by three metres.

New evidence suggests the East Antarctic ice sheet could be similarly unstable, and precipitate further sea level rise of up to four metres. Hundreds of millions are already at risk from coastal flooding.

Timescale controlled

The Greenland ice sheet is melting at an accelerating rate, and once past a critical threshold could lose enough water to raise sea levels by seven metres. Even a 1.5°C warming might condemn Greenland to irreversible melting – and on present form the world could warm by 1.5°C by 2030.

“Thus we might have already committed future generations to living with sea level rises of around 10m over thousands of years. But the timescale is still under our control,” the authors warn.

They also warn that a “staggering 99% of tropical corals” could be lost if the planet heats by even 2°C – at a profound cost to both marine sea life and human economies.

They say 17% of the Amazon rainforest has been lost since 1970: a loss of somewhere between 20% and 40% could tip the entire rainforest into a destabilised state, increasingly at risk from drought and fire.

Risks multiply

In the boreal forests of northern Asia, Europe and Canada, insect outbreaks, fire and dieback could turn some regions into sources of more carbon, rather than sinks that soak up the extra carbon dioxide.

Permafrost thaw could release ever-greater volumes of stored methane, a greenhouse gas 30 times more potent, over a century, than carbon dioxide, and so on. The dangers multiply, and each one amplifies planetary heating.

“If damaging tipping cascades can occur and a global tipping point cannot be ruled out, then this is an existential threat to civilisation,” the authors warn.

“The stability and resilience of our planet is in peril. International action – not just words – must reflect this.” – Climate News Network