Tag Archives: Greenland

Melting Arctic needs new name to match reality

Change in the far north is happening so fast that soon the melting Arctic won’t be arctic any more.

LONDON, 16 September, 2020 − The word Arctic may be up for redefinition. The conditions within the melting Arctic Circle are changing so fast that what was once a frozen seascape could now be entering a new climate regime in which nothing is predictable.

Even in an unusually cold year, the sea ice may not return to the summer limits normal in the last century. For some months of autumn and even winter, rain will fall instead of snow, US scientists report in the journal Nature Climate Change.

“The rate of change is remarkable,” said Laura Landrum, of the US National Centre for Atmospheric Research, who led the study.

“It’s a period of such rapid change that observations of past weather patterns no longer show what you can expect next year. The Arctic is already entering a completely different climate than just a few decades ago.”

She and a colleague looked at four decades of satellite data and ground observations and hundreds of computer simulations to confirm that polar warming is happening at such a rate that any change year to year is no longer within the extremes of the past. Conditions that were once normally changeable are now abnormally so.

“The Arctic is already entering a completely different climate than just a few decades ago … We need to change our definition of what the Arctic is”

Climate in the northern hemisphere is moderated by temperature differences that vary with latitude: between them, a torrid equator and a frozen Arctic drive the prevailing winds and ocean currents and the mix of cloud, sunshine, rainfall, frost, windstorm, dry spells and seasonal flooding in which agriculture, industry and civilisation have evolved for the last 10,000 years.

But as carbon dioxide levels in the atmosphere soar in response to rapidly-increasing use of fossil fuels, the melting Arctic has been warming far more swiftly than the planet as a whole.

The extent of summer sea ice in each of the last 13 years has been lower than any minimum observed since 1979, when systematic observation began. Winters have been warmer, winter sea ice has been reduced, rain has been falling on snow ever earlier.

The climate scientists posed themselves the simple question: “While these changes appear extreme compared with the recent past, are they climate extremes in a statistical sense, or do they represent expected events in a new Arctic climate?”

New climate develops

The answer seems to be: yes. The researchers tested their statistical techniques on five different climate simulations. Each of these showed the sea ice retreating so dramatically that a new climate had emerged some time in the late 20th and early 21st centuries.

The finding fits a pattern of foreboding delivered by recent research. In the last two months, researchers have warned that ice loss in the Arctic regions has been so severe that the region’s most charismatic predator, the polar bear, may be gone by the century’s end.

Another group has warned that the Arctic ocean in late summer may be effectively ice-free within the next 15 years.

One group has concluded that ice loss from Greenland is now at such a rate as to be irreversible, and another has confirmed that the rate of ice melt from the northern hemisphere’s biggest reserve – enough to raise sea levels six or seven metres – last year reached new records.

And this month an international research team reported that the rate of change in the Arctic has exceeded the “worst-case” scenario proposed by climate researchers.

Unknown extremes ahead

Dr Landrum and her colleague report that − if greenhouse gas emissions continue at their present rate − some of their climate forecasts predict a mostly ice-free Arctic for between three and 10 months a year, every year, by the end of the century.

Air temperatures over the ocean in autumn and winter will become warmer before or by mid-century, and then start warming over land in the second half.

In a warmer world, more water will evaporate and fall again as rain. Over Alaska, northern Canada and northern Siberia there will be more rain rather than snow: by mid-century, perhaps an extra 20 to 60 days, and by 2100, perhaps from 60 to an extra 90 days. In some parts of the Arctic, by the century’s end, rain might fall in any month of the year.

“The Arctic is likely to experience extremes in sea ice, temperature and precipitation that are far outside anything we’ve experienced before,” Dr Landrum said. “We need to change our definition of what the Arctic is.” − Climate News Network

Change in the far north is happening so fast that soon the melting Arctic won’t be arctic any more.

LONDON, 16 September, 2020 − The word Arctic may be up for redefinition. The conditions within the melting Arctic Circle are changing so fast that what was once a frozen seascape could now be entering a new climate regime in which nothing is predictable.

Even in an unusually cold year, the sea ice may not return to the summer limits normal in the last century. For some months of autumn and even winter, rain will fall instead of snow, US scientists report in the journal Nature Climate Change.

“The rate of change is remarkable,” said Laura Landrum, of the US National Centre for Atmospheric Research, who led the study.

“It’s a period of such rapid change that observations of past weather patterns no longer show what you can expect next year. The Arctic is already entering a completely different climate than just a few decades ago.”

She and a colleague looked at four decades of satellite data and ground observations and hundreds of computer simulations to confirm that polar warming is happening at such a rate that any change year to year is no longer within the extremes of the past. Conditions that were once normally changeable are now abnormally so.

“The Arctic is already entering a completely different climate than just a few decades ago … We need to change our definition of what the Arctic is”

Climate in the northern hemisphere is moderated by temperature differences that vary with latitude: between them, a torrid equator and a frozen Arctic drive the prevailing winds and ocean currents and the mix of cloud, sunshine, rainfall, frost, windstorm, dry spells and seasonal flooding in which agriculture, industry and civilisation have evolved for the last 10,000 years.

But as carbon dioxide levels in the atmosphere soar in response to rapidly-increasing use of fossil fuels, the melting Arctic has been warming far more swiftly than the planet as a whole.

The extent of summer sea ice in each of the last 13 years has been lower than any minimum observed since 1979, when systematic observation began. Winters have been warmer, winter sea ice has been reduced, rain has been falling on snow ever earlier.

The climate scientists posed themselves the simple question: “While these changes appear extreme compared with the recent past, are they climate extremes in a statistical sense, or do they represent expected events in a new Arctic climate?”

New climate develops

The answer seems to be: yes. The researchers tested their statistical techniques on five different climate simulations. Each of these showed the sea ice retreating so dramatically that a new climate had emerged some time in the late 20th and early 21st centuries.

The finding fits a pattern of foreboding delivered by recent research. In the last two months, researchers have warned that ice loss in the Arctic regions has been so severe that the region’s most charismatic predator, the polar bear, may be gone by the century’s end.

Another group has warned that the Arctic ocean in late summer may be effectively ice-free within the next 15 years.

One group has concluded that ice loss from Greenland is now at such a rate as to be irreversible, and another has confirmed that the rate of ice melt from the northern hemisphere’s biggest reserve – enough to raise sea levels six or seven metres – last year reached new records.

And this month an international research team reported that the rate of change in the Arctic has exceeded the “worst-case” scenario proposed by climate researchers.

Unknown extremes ahead

Dr Landrum and her colleague report that − if greenhouse gas emissions continue at their present rate − some of their climate forecasts predict a mostly ice-free Arctic for between three and 10 months a year, every year, by the end of the century.

Air temperatures over the ocean in autumn and winter will become warmer before or by mid-century, and then start warming over land in the second half.

In a warmer world, more water will evaporate and fall again as rain. Over Alaska, northern Canada and northern Siberia there will be more rain rather than snow: by mid-century, perhaps an extra 20 to 60 days, and by 2100, perhaps from 60 to an extra 90 days. In some parts of the Arctic, by the century’s end, rain might fall in any month of the year.

“The Arctic is likely to experience extremes in sea ice, temperature and precipitation that are far outside anything we’ve experienced before,” Dr Landrum said. “We need to change our definition of what the Arctic is.” − Climate News Network

In Arctic heat Greenland’s ice loss grows faster still

Greenland’s ice loss tipped a new record last year. This ominous milestone is just the latest in a run of alarming news.

LONDON, 24 August, 2020 – Its icecap is now smaller than at any time since measurements began: Greenland’s ice loss means it lost mass in 2019 at a record rate.

By the close of the year, thanks to high summer melt and low snowfall, the northern hemisphere’s biggest reservoir of ice had shed 532 billion tonnes into the sea – raising global sea levels by around 1.5mm in a year.

The previous record loss for Greenland was in 2012. In that year, the island lost 464 billion tonnes, according to studies of satellite data published by European scientists in the journal Communications Earth and Environment.

Greenland’s ice cap has been shrinking, if unsteadily, for many years. In 2017 and 2018, the losses continued, but only at around 100bn tonnes a year.

“After a two-year breather, the mass loss increased steeply and exceeded all annual losses since 1948, and probably for more than 100 years,” said Ingo Sasgen of the Alfred Wegener Institute in Bremerhaven, Germany, who led the study.

“There are increasingly frequent, stable high-pressure areas over the ice sheet, which promote the influx of warm air from the middle latitudes. We saw a similar pattern in the previous record year, 2012.”

“The ice sheet has lost ice every year for the past 20. If everyone’s alarm bells were not already ringing, they must be now”

He and colleagues made their calculations from data delivered by two Nasa satellites, GRACE and GRACE-FO, that measure changes in the surface gravity of the planet: a way of calculating the mass of water stored as ice, or in aquifers, and observing sea level change.

The finding is the latest in a succession of polar climate alarms. It follows closely on a warning from US scientists that ice loss from Greenland may  have reached the point of no return.

And it also follows a sober calculation of the alarming rate of planetary temperature rise in response to ever-higher use of fossil fuels that trigger ever-higher measures of greenhouse gases in the atmosphere.

And that in turn followed a warning that the entire Arctic was now warming so swiftly that the Arctic sea ice might be all but gone in the summer of 2035.

And that was only days after another research team, looking at the big picture of climate change, warned that the scenario climate forecasters liked to use as an example of their “worst case” was now a simple description of what was already happening.

“It is devastating that 2019 was another record year of ice loss. In 2012, it had been about 150 years since the ice sheet had experienced similar melt extent, and then a further 600-plus years back to find another similar event,” said Twila Moon, of the University of Colorado at Boulder, who was not involved in the research.

Damage off the scale

“We have now had record-breaking ice loss twice in less than 10 years, and the ice sheet has lost ice every year for the past 20. If everyone’s alarm bells were not already ringing, they must be now.”

The implications of continued loss of Greenland ice have been explored repeatedly: the run-off of fresh water from the ice cap to the sea is now so great that the North Atlantic is now “fresher” than at any time in the last 100 years.

And this change in water temperature and chemistry could – on the evidence of the distant past – possibly slow or switch off the circulation of the North Atlantic current, which for most of the history of human civilisation has kept the United Kingdom and north-western Europe from five to 10°C warmer than similar latitudes elsewhere.

“This tipping point in the climate system is one of the potential climate disasters facing us,” said Stuart Cunningham of the Scottish Association for Marine Science, commenting on the study.

“To transform the way we power, finance and run the world in the way we know we should is proving entirely beyond us,” said Chris Rapley, now a climate scientist at University College London, but once director of the British Antarctic Survey.

“Torpor, incompetence and indifference at the top may kill people in a health crisis, and torpedo the careers of young students in an education crisis; but the damage they are generating in the pipeline from climate change is on another scale.” – Climate News Network

Greenland’s ice loss tipped a new record last year. This ominous milestone is just the latest in a run of alarming news.

LONDON, 24 August, 2020 – Its icecap is now smaller than at any time since measurements began: Greenland’s ice loss means it lost mass in 2019 at a record rate.

By the close of the year, thanks to high summer melt and low snowfall, the northern hemisphere’s biggest reservoir of ice had shed 532 billion tonnes into the sea – raising global sea levels by around 1.5mm in a year.

The previous record loss for Greenland was in 2012. In that year, the island lost 464 billion tonnes, according to studies of satellite data published by European scientists in the journal Communications Earth and Environment.

Greenland’s ice cap has been shrinking, if unsteadily, for many years. In 2017 and 2018, the losses continued, but only at around 100bn tonnes a year.

“After a two-year breather, the mass loss increased steeply and exceeded all annual losses since 1948, and probably for more than 100 years,” said Ingo Sasgen of the Alfred Wegener Institute in Bremerhaven, Germany, who led the study.

“There are increasingly frequent, stable high-pressure areas over the ice sheet, which promote the influx of warm air from the middle latitudes. We saw a similar pattern in the previous record year, 2012.”

“The ice sheet has lost ice every year for the past 20. If everyone’s alarm bells were not already ringing, they must be now”

He and colleagues made their calculations from data delivered by two Nasa satellites, GRACE and GRACE-FO, that measure changes in the surface gravity of the planet: a way of calculating the mass of water stored as ice, or in aquifers, and observing sea level change.

The finding is the latest in a succession of polar climate alarms. It follows closely on a warning from US scientists that ice loss from Greenland may  have reached the point of no return.

And it also follows a sober calculation of the alarming rate of planetary temperature rise in response to ever-higher use of fossil fuels that trigger ever-higher measures of greenhouse gases in the atmosphere.

And that in turn followed a warning that the entire Arctic was now warming so swiftly that the Arctic sea ice might be all but gone in the summer of 2035.

And that was only days after another research team, looking at the big picture of climate change, warned that the scenario climate forecasters liked to use as an example of their “worst case” was now a simple description of what was already happening.

“It is devastating that 2019 was another record year of ice loss. In 2012, it had been about 150 years since the ice sheet had experienced similar melt extent, and then a further 600-plus years back to find another similar event,” said Twila Moon, of the University of Colorado at Boulder, who was not involved in the research.

Damage off the scale

“We have now had record-breaking ice loss twice in less than 10 years, and the ice sheet has lost ice every year for the past 20. If everyone’s alarm bells were not already ringing, they must be now.”

The implications of continued loss of Greenland ice have been explored repeatedly: the run-off of fresh water from the ice cap to the sea is now so great that the North Atlantic is now “fresher” than at any time in the last 100 years.

And this change in water temperature and chemistry could – on the evidence of the distant past – possibly slow or switch off the circulation of the North Atlantic current, which for most of the history of human civilisation has kept the United Kingdom and north-western Europe from five to 10°C warmer than similar latitudes elsewhere.

“This tipping point in the climate system is one of the potential climate disasters facing us,” said Stuart Cunningham of the Scottish Association for Marine Science, commenting on the study.

“To transform the way we power, finance and run the world in the way we know we should is proving entirely beyond us,” said Chris Rapley, now a climate scientist at University College London, but once director of the British Antarctic Survey.

“Torpor, incompetence and indifference at the top may kill people in a health crisis, and torpedo the careers of young students in an education crisis; but the damage they are generating in the pipeline from climate change is on another scale.” – Climate News Network

Greenland is losing more ice than it gains annually

The ice lost to the sea annually off Greenland is now more than the snow falling on the island. This is a tipping point.

LONDON, 18 August, 2020 – The loss of ice from Greenland may have reached the point of no return. The island’s glaciers have dwindled and retreated so much that annual snowfall can no longer replace the lost ice.

New studies confirm that between 1980 and the year 2000, the island – the biggest single store of ice in the northern hemisphere – lost on average 450 billion tonnes of ice each year from its glaciers. This is about what falls as snow and stays on the island’s surface each year.

And then 20 years ago the rate of melt – already speeding up – accelerated again. The glaciers are now spilling more than 500 billion tonnes of ice into the seas. But snowfall has not increased.

And US scientists warn, in the normally guarded language of science, of a “switch to a new dynamic state of sustained mass loss that would persist even under a decline in surface melt.”

“Glacier retreat has knocked the dynamics of the whole ice sheet into a constant state of loss”

The scientists base their new conclusions on a careful re-examination of 40 years of satellite observations to check the rates of snowfall and ice loss. “What we’ve found is that the ice that’s discharging into the ocean is far surpassing the snow that’s accumulating on the surface of the ice sheet,” said Michalea King of Ohio State University, who led the research. .

The news, in the journal Nature Communications Earth and Environment, is alarming but hardly surprising. In December researchers warned that – even to begin to arrest the melting of a store of ice big enough to raise global sea levels by up to seven metres the world would have to take immediate and drastic steps to halt global heating.

Researchers have found that surface melting is at a rate that has begun to make the glaciers more unstable. They have confirmed that the rate of melt is accelerating so swiftly that the bedrock beneath the weight of ice has begun to rise, while a range of other climate change triggers has begun to darken the ice cover in ways that can only increase the absorption of heat and step up the rate of melt.

The latest evidence is that the world has passed a tipping point of sorts: once such things happen, there is no way back.

Glaciers gather speed

All icecaps melt in summer, and all icecaps are drained by glaciers, rivers of ice that make slow progress to the sea. In a stable climate, annual precipitation and annual glacier calving remain more or less in balance, and the icecap functions as its own refrigerant. The whiteness of the ice reflects sunlight back into space and insulates itself against significant loss.

But as the air and oceans warm in response to ever higher levels of greenhouse gases pumped into the atmosphere as nations continue to burn ever more coal, oil and gas, the rates of melt became more dramatic and the glaciers began to flow ever faster: one of them was clocked at 45 metres a day.

The message of the latest research is that, even if somehow humans could immediately halt climate change, the ice likely to be lost as the glaciers reach the sea would still be greater than the accumulation of ice on the surface each winter.

“Glacier retreat has knocked the dynamics of the whole ice sheet into a constant state of loss,” said Ian Howat, a co-author at Ohio State University. “Even if the climate were to stay the same or get a little colder, the ice sheet would still be losing mass.” – Climate News Network

The ice lost to the sea annually off Greenland is now more than the snow falling on the island. This is a tipping point.

LONDON, 18 August, 2020 – The loss of ice from Greenland may have reached the point of no return. The island’s glaciers have dwindled and retreated so much that annual snowfall can no longer replace the lost ice.

New studies confirm that between 1980 and the year 2000, the island – the biggest single store of ice in the northern hemisphere – lost on average 450 billion tonnes of ice each year from its glaciers. This is about what falls as snow and stays on the island’s surface each year.

And then 20 years ago the rate of melt – already speeding up – accelerated again. The glaciers are now spilling more than 500 billion tonnes of ice into the seas. But snowfall has not increased.

And US scientists warn, in the normally guarded language of science, of a “switch to a new dynamic state of sustained mass loss that would persist even under a decline in surface melt.”

“Glacier retreat has knocked the dynamics of the whole ice sheet into a constant state of loss”

The scientists base their new conclusions on a careful re-examination of 40 years of satellite observations to check the rates of snowfall and ice loss. “What we’ve found is that the ice that’s discharging into the ocean is far surpassing the snow that’s accumulating on the surface of the ice sheet,” said Michalea King of Ohio State University, who led the research. .

The news, in the journal Nature Communications Earth and Environment, is alarming but hardly surprising. In December researchers warned that – even to begin to arrest the melting of a store of ice big enough to raise global sea levels by up to seven metres the world would have to take immediate and drastic steps to halt global heating.

Researchers have found that surface melting is at a rate that has begun to make the glaciers more unstable. They have confirmed that the rate of melt is accelerating so swiftly that the bedrock beneath the weight of ice has begun to rise, while a range of other climate change triggers has begun to darken the ice cover in ways that can only increase the absorption of heat and step up the rate of melt.

The latest evidence is that the world has passed a tipping point of sorts: once such things happen, there is no way back.

Glaciers gather speed

All icecaps melt in summer, and all icecaps are drained by glaciers, rivers of ice that make slow progress to the sea. In a stable climate, annual precipitation and annual glacier calving remain more or less in balance, and the icecap functions as its own refrigerant. The whiteness of the ice reflects sunlight back into space and insulates itself against significant loss.

But as the air and oceans warm in response to ever higher levels of greenhouse gases pumped into the atmosphere as nations continue to burn ever more coal, oil and gas, the rates of melt became more dramatic and the glaciers began to flow ever faster: one of them was clocked at 45 metres a day.

The message of the latest research is that, even if somehow humans could immediately halt climate change, the ice likely to be lost as the glaciers reach the sea would still be greater than the accumulation of ice on the surface each winter.

“Glacier retreat has knocked the dynamics of the whole ice sheet into a constant state of loss,” said Ian Howat, a co-author at Ohio State University. “Even if the climate were to stay the same or get a little colder, the ice sheet would still be losing mass.” – Climate News Network

North Pole may be clear water by mid-century

This story is a part of Covering Climate Now’s week of coverage focused on Climate Solutions, to mark the 50th anniversary of Earth Day. Covering Climate Now is a global journalism collaboration committed to strengthening coverage of the climate story.

 

Within 30 years, there could be clear blue water over the North Pole – not good news for most of the planet.

LONDON, 25 April, 2020 – Within three decades, the North Pole could be free of sea ice in the late summer. The latest and most advanced climate simulations, tested by 21 research institutes from around the world, predict that if humans go on emitting ever-greater volumes of carbon dioxide from fossil fuel combustion and other actions, then before 2050, for the first time in human history, there could be no ice over the North Pole.

And a team of research scientists aboard a ship intent on spending a year observing the drift of sea ice across the Arctic Ocean has been warned that they may have to finish early: the ice supposed to hold the ship fast could melt too soon.

The loss of sea ice promises devastating consequences for the rich life in the most northern waters. The ice reflects sunlight back into space and keeps the Arctic cool. It also provides space for seals on which to haul out, and hunting grounds for blubber-hungry polar bears.

And although human inaction in the climate emergency makes the loss of polar ice ever more probable, so much greenhouse gas has already built up in the planetary atmosphere that it could happen anyway.

Taken aback

“If we reduce global emissions rapidly and substantially, and thus keep our warming below 2°C relative to pre-industrial levels, sea ice will nevertheless likely disappear occasionally in summer even before 2050,” said Dirk Notz, of the University of Hamburg in Germany, who led the study. “This really surprised us.”

Climate scientists first warned of the accelerating loss of Arctic sea ice two decades ago, and have repeatedly re-examined the climate predictions, each time with much the same outcome.

The loss of ice promises new trade routes between Atlantic and Pacific Oceans, but the cost of a warming Arctic could have catastrophic economic consequences.

The pattern of the northern hemisphere climate is driven by the temperature difference between the Arctic and the tropics, and rapid polar warming both disturbs temperate climate regimes and brings ever higher sea levels, with accelerating ice loss from Greenland, which right now bears enough ice to raise global sea levels by more than seven metres.

“The changes in the Arctic system are so incredibly rapid that even our satellite observations from 15 years ago are unlike the Arctic today”

Dr Notz and his co-authors report in the journal Geophysical Research Letters that they used the very latest climate model developed for the Intergovernmental Panel on Climate Change and tested it on a range of 40 possible climate outcomes.

In most simulations, the Arctic sea ice was reduced to less than a million square kilometres – polar researchers call this “practically sea-ice free” – in the month of September for the first time before 2050. Even if human fossil fuel use was sharply reduced, the ocean could be free of ice some years; if not, the pole could become open water most years.

And a second study, in the journal The Cryosphere, offers a measure of the sea ice loss even now. More than a century ago, the great explorer Fridtjof Nansen sailed his ship the Fram into the polar ice, became fast, and travelled with the floe across the Arctic Ocean.

His became the first scientific observation of a phenomenon called the trans-Polar drift, which takes algae, sediments and nutrients – and increasingly, plastic pollution – across the Arctic from Siberia to Canada and Greenland.

Melted out

In October a team of international researchers boarded a vessel called Polarstern with the intention of measuring the ice movement in the modern Arctic in more detail. They had planned for a year fast in the ice. Their project even has a name: Mosaic, or Multidisciplinary drifting Observatory for the Study of Arctic Climate.

But climate simulations by the US scientists reveal that in every sense, the project is on thin ice and could end prematurely. The flow of ice could be faster, and carry the ship further, than expected: nearly one in five of the simulations also predicted that the ship could melt out of the ice in less than a year.

“The changes in the Arctic system are so incredibly rapid that even our satellite observations from 15 years ago are unlike the Arctic today,” said one of the authors, Marika Holland of the US National Center for Atmospheric Research.

“Now there is thinner ice, which moves more quickly, and there is less snow cover. It is a totally different ice regime.” – Climate News Network

This story is a part of Covering Climate Now’s week of coverage focused on Climate Solutions, to mark the 50th anniversary of Earth Day. Covering Climate Now is a global journalism collaboration committed to strengthening coverage of the climate story.

 

Within 30 years, there could be clear blue water over the North Pole – not good news for most of the planet.

LONDON, 25 April, 2020 – Within three decades, the North Pole could be free of sea ice in the late summer. The latest and most advanced climate simulations, tested by 21 research institutes from around the world, predict that if humans go on emitting ever-greater volumes of carbon dioxide from fossil fuel combustion and other actions, then before 2050, for the first time in human history, there could be no ice over the North Pole.

And a team of research scientists aboard a ship intent on spending a year observing the drift of sea ice across the Arctic Ocean has been warned that they may have to finish early: the ice supposed to hold the ship fast could melt too soon.

The loss of sea ice promises devastating consequences for the rich life in the most northern waters. The ice reflects sunlight back into space and keeps the Arctic cool. It also provides space for seals on which to haul out, and hunting grounds for blubber-hungry polar bears.

And although human inaction in the climate emergency makes the loss of polar ice ever more probable, so much greenhouse gas has already built up in the planetary atmosphere that it could happen anyway.

Taken aback

“If we reduce global emissions rapidly and substantially, and thus keep our warming below 2°C relative to pre-industrial levels, sea ice will nevertheless likely disappear occasionally in summer even before 2050,” said Dirk Notz, of the University of Hamburg in Germany, who led the study. “This really surprised us.”

Climate scientists first warned of the accelerating loss of Arctic sea ice two decades ago, and have repeatedly re-examined the climate predictions, each time with much the same outcome.

The loss of ice promises new trade routes between Atlantic and Pacific Oceans, but the cost of a warming Arctic could have catastrophic economic consequences.

The pattern of the northern hemisphere climate is driven by the temperature difference between the Arctic and the tropics, and rapid polar warming both disturbs temperate climate regimes and brings ever higher sea levels, with accelerating ice loss from Greenland, which right now bears enough ice to raise global sea levels by more than seven metres.

“The changes in the Arctic system are so incredibly rapid that even our satellite observations from 15 years ago are unlike the Arctic today”

Dr Notz and his co-authors report in the journal Geophysical Research Letters that they used the very latest climate model developed for the Intergovernmental Panel on Climate Change and tested it on a range of 40 possible climate outcomes.

In most simulations, the Arctic sea ice was reduced to less than a million square kilometres – polar researchers call this “practically sea-ice free” – in the month of September for the first time before 2050. Even if human fossil fuel use was sharply reduced, the ocean could be free of ice some years; if not, the pole could become open water most years.

And a second study, in the journal The Cryosphere, offers a measure of the sea ice loss even now. More than a century ago, the great explorer Fridtjof Nansen sailed his ship the Fram into the polar ice, became fast, and travelled with the floe across the Arctic Ocean.

His became the first scientific observation of a phenomenon called the trans-Polar drift, which takes algae, sediments and nutrients – and increasingly, plastic pollution – across the Arctic from Siberia to Canada and Greenland.

Melted out

In October a team of international researchers boarded a vessel called Polarstern with the intention of measuring the ice movement in the modern Arctic in more detail. They had planned for a year fast in the ice. Their project even has a name: Mosaic, or Multidisciplinary drifting Observatory for the Study of Arctic Climate.

But climate simulations by the US scientists reveal that in every sense, the project is on thin ice and could end prematurely. The flow of ice could be faster, and carry the ship further, than expected: nearly one in five of the simulations also predicted that the ship could melt out of the ice in less than a year.

“The changes in the Arctic system are so incredibly rapid that even our satellite observations from 15 years ago are unlike the Arctic today,” said one of the authors, Marika Holland of the US National Center for Atmospheric Research.

“Now there is thinner ice, which moves more quickly, and there is less snow cover. It is a totally different ice regime.” – Climate News Network

Cloudless skies hasten Greenland’s ice loss

This story is a part of Covering Climate Now’s week of coverage focused on Climate Solutions, to mark the 50th anniversary of Earth Day. Covering Climate Now is a global journalism collaboration committed to strengthening coverage of the climate story.

 

The bad news about Greenland’s ice loss has just got even worse. Blame it on mischief by blue skies all day long.

LONDON, 22 April, 2020 – Greenland’s ice loss reached record levels in 2019, and scientists think they’ve identified the culprit: the good weather which normally brings the snow-bearing clouds to the High Arctic.

The huge island, the biggest bank of ice in the northern hemisphere, has been losing ice at an ever-increasing rate in a rapidly warming world. Last year it shed more ice than ever, and this time because the skies were unusually clear.

There is enough ice on Greenland to raise global sea levels by more than seven metres. A recent study established that in the years between 1992 and 2018, rates of polar ice loss have risen six-fold, and so much water has flowed off the Greenland ice surface that sea levels have risen by more than 10mm everywhere.

Now a new study by US and Belgian scientists in the journal The Cryosphere confirms that 2019 was even worse. Because of good weather and cloudless skies, only enough snow fell to deposit 50 billion tonnes of ice into the island’s profit-and-loss ice account. The average annual deposit between 1981 and 2010 was about 375bn tonnes.

But glaciers still flowed towards the sea at an ever-increasing rate, summer snow melt continued to flow off the ice sheet, and icebergs continued to calve, so on balance the island lost 600 billion tonnes of ice: enough to raise global sea levels by 1.5mm. This is the biggest overall loss of ice since records in Greenland began in 1948.

“These atmospheric conditions are becoming more and more frequent over the past few decades. It is very likely that this is due to the waviness of the jet stream”

The cause: unusual spells of high atmospheric pressure over the island for unusually long periods of time. That stopped the formation of clouds, and that meant less precipitation, in the form of snow. Snow reflects solar radiation more effectively than ice, so the surface absorbed more heat and melting also accelerated.

The pattern of warm moist clouds trapped over northern Greenland by the heat that would normally radiate off the ice, instead of releasing snow, also emitted their own heat, to make things worse. The worst year for surface melting remains 2012, but the summer of 2019 was a good second.

The implication is that things could get worse, and losses of Greenland ice could accelerate.

“These atmospheric conditions are becoming more and more frequent over the past few decades,” said Marco Tedesco, of the Lamont-Doherty Earth Observatory at the University of Columbia in the US, the lead author.

“It is very likely that this is due to the waviness of the jet stream, which we think is related to, among other things, the disappearance of snow cover in Siberia, the disappearance of sea ice, and the difference in the rate at which temperature is increasing in the Arctic versus the mid-latitudes.” – Climate News Network

This story is a part of Covering Climate Now’s week of coverage focused on Climate Solutions, to mark the 50th anniversary of Earth Day. Covering Climate Now is a global journalism collaboration committed to strengthening coverage of the climate story.

 

The bad news about Greenland’s ice loss has just got even worse. Blame it on mischief by blue skies all day long.

LONDON, 22 April, 2020 – Greenland’s ice loss reached record levels in 2019, and scientists think they’ve identified the culprit: the good weather which normally brings the snow-bearing clouds to the High Arctic.

The huge island, the biggest bank of ice in the northern hemisphere, has been losing ice at an ever-increasing rate in a rapidly warming world. Last year it shed more ice than ever, and this time because the skies were unusually clear.

There is enough ice on Greenland to raise global sea levels by more than seven metres. A recent study established that in the years between 1992 and 2018, rates of polar ice loss have risen six-fold, and so much water has flowed off the Greenland ice surface that sea levels have risen by more than 10mm everywhere.

Now a new study by US and Belgian scientists in the journal The Cryosphere confirms that 2019 was even worse. Because of good weather and cloudless skies, only enough snow fell to deposit 50 billion tonnes of ice into the island’s profit-and-loss ice account. The average annual deposit between 1981 and 2010 was about 375bn tonnes.

But glaciers still flowed towards the sea at an ever-increasing rate, summer snow melt continued to flow off the ice sheet, and icebergs continued to calve, so on balance the island lost 600 billion tonnes of ice: enough to raise global sea levels by 1.5mm. This is the biggest overall loss of ice since records in Greenland began in 1948.

“These atmospheric conditions are becoming more and more frequent over the past few decades. It is very likely that this is due to the waviness of the jet stream”

The cause: unusual spells of high atmospheric pressure over the island for unusually long periods of time. That stopped the formation of clouds, and that meant less precipitation, in the form of snow. Snow reflects solar radiation more effectively than ice, so the surface absorbed more heat and melting also accelerated.

The pattern of warm moist clouds trapped over northern Greenland by the heat that would normally radiate off the ice, instead of releasing snow, also emitted their own heat, to make things worse. The worst year for surface melting remains 2012, but the summer of 2019 was a good second.

The implication is that things could get worse, and losses of Greenland ice could accelerate.

“These atmospheric conditions are becoming more and more frequent over the past few decades,” said Marco Tedesco, of the Lamont-Doherty Earth Observatory at the University of Columbia in the US, the lead author.

“It is very likely that this is due to the waviness of the jet stream, which we think is related to, among other things, the disappearance of snow cover in Siberia, the disappearance of sea ice, and the difference in the rate at which temperature is increasing in the Arctic versus the mid-latitudes.” – Climate News Network

Northern Europe’s warm water flow may falter

Global heating can stop the flow of Europe’s warm water from the tropics. Happening often during the Ice Ages, it could soon recur.

LONDON, 1 April, 2020 – Oceanographers have confirmed once again that global heating could slow or shut down the flow of currents such as the Gulf Stream, ending northern Europe’s warm water supply with an unexpected and prolonged cold snap.

This time the confidence is based neither on ocean measurements made now, nor complex computer simulations of the future. There is fresh evidence from the sea floor that such an ocean shutdown happened many times in the last half a million years of Ice Ages.

The Gulf Stream is part of a much larger flow of water called the Atlantic Meridional Overturning Circulation, an ocean recycling system that both nourishes marine life and moderates the climate in two hemispheres.

For the last 10,000 years of human history, tropical water has flowed north from the Caribbean and equatorial regions and washed the shores of Europe as far north as Norway, bringing equatorial heat to soften the impact of European winters.

A former UK chief scientist once calculated that the Gulf Stream delivered the warmth of 27,000 power stations and kept Britain about 5°C warmer than its citizens had any right to expect, given the latitude at which they lived.

“These findings suggest that our climate system, which depends greatly on deep ocean circulation, is critically poised near a tipping point for abrupt disruptions”

But as that stretch of the Gulf Stream known to oceanographers as the North Atlantic drift current reaches the Greenland Sea it becomes increasingly colder and saltier and thus more dense, and sinks to the ocean floor, loaded with dissolved atmospheric carbon dioxide and oxygen, to become a southward flow called the North Atlantic Deepwater formation.

And it also mingles with fresh water melting each summer from the Greenland ice sheet. But as the rate of Arctic melting accelerates, more fresh water will plunge into the same sea, with an increasing probability that it will disrupt the ocean cycle, turn off the flow of warm tropical water, and plunge Europe into a prolonged cold spell.

In its most dramatic form, this hypothesis was the basis for a 2004 Hollywood disaster movie called The Day After Tomorrow. Climate scientists are fairly sure that such an event would not mean the sudden advance of glacial ice over much of Europe and North America. But they have repeatedly identified evidence that the flow of the northward current is beginning to weaken.

And the journal Science now carries additional evidence that the ocean circulation was repeatedly interrupted for periods of a century or more during the warm spells or interglacials that have happened during the last 450,000 years.

Shells’ signatures

The signature of ocean change is there in the tiny sea shells from marine creatures called foraminifera that rain down onto the ocean floor to form annual layers of silent testimony to past climates.

When the mix of carbon isotope ratios preserved in them is high, that is a sign that the Atlantic circulation was once vigorous. When it is low, then this overturning circulation is feeble, or has stopped altogether.

The signal from the deep ocean is that when they happen, these disruptions seem to happen very swiftly, and to linger for 100 years or more. And, the scientists say, these interruptions in the flow of the ocean – and with it, the transport of heat from the tropics – happen more easily than previously appreciated, and they occurred in past climate conditions similar to those the world may soon face.

“These findings suggest that our climate system, which depends greatly on deep ocean circulation, is critically poised near a tipping point for abrupt disruptions,” said Yair Rosenthal of Rutgers University in the US, one of the authors.

“Although the disruptions in circulation and possible coolings may be relatively short-lived – lasting maybe a century or more – the consequences might be large.” – Climate News Network

Global heating can stop the flow of Europe’s warm water from the tropics. Happening often during the Ice Ages, it could soon recur.

LONDON, 1 April, 2020 – Oceanographers have confirmed once again that global heating could slow or shut down the flow of currents such as the Gulf Stream, ending northern Europe’s warm water supply with an unexpected and prolonged cold snap.

This time the confidence is based neither on ocean measurements made now, nor complex computer simulations of the future. There is fresh evidence from the sea floor that such an ocean shutdown happened many times in the last half a million years of Ice Ages.

The Gulf Stream is part of a much larger flow of water called the Atlantic Meridional Overturning Circulation, an ocean recycling system that both nourishes marine life and moderates the climate in two hemispheres.

For the last 10,000 years of human history, tropical water has flowed north from the Caribbean and equatorial regions and washed the shores of Europe as far north as Norway, bringing equatorial heat to soften the impact of European winters.

A former UK chief scientist once calculated that the Gulf Stream delivered the warmth of 27,000 power stations and kept Britain about 5°C warmer than its citizens had any right to expect, given the latitude at which they lived.

“These findings suggest that our climate system, which depends greatly on deep ocean circulation, is critically poised near a tipping point for abrupt disruptions”

But as that stretch of the Gulf Stream known to oceanographers as the North Atlantic drift current reaches the Greenland Sea it becomes increasingly colder and saltier and thus more dense, and sinks to the ocean floor, loaded with dissolved atmospheric carbon dioxide and oxygen, to become a southward flow called the North Atlantic Deepwater formation.

And it also mingles with fresh water melting each summer from the Greenland ice sheet. But as the rate of Arctic melting accelerates, more fresh water will plunge into the same sea, with an increasing probability that it will disrupt the ocean cycle, turn off the flow of warm tropical water, and plunge Europe into a prolonged cold spell.

In its most dramatic form, this hypothesis was the basis for a 2004 Hollywood disaster movie called The Day After Tomorrow. Climate scientists are fairly sure that such an event would not mean the sudden advance of glacial ice over much of Europe and North America. But they have repeatedly identified evidence that the flow of the northward current is beginning to weaken.

And the journal Science now carries additional evidence that the ocean circulation was repeatedly interrupted for periods of a century or more during the warm spells or interglacials that have happened during the last 450,000 years.

Shells’ signatures

The signature of ocean change is there in the tiny sea shells from marine creatures called foraminifera that rain down onto the ocean floor to form annual layers of silent testimony to past climates.

When the mix of carbon isotope ratios preserved in them is high, that is a sign that the Atlantic circulation was once vigorous. When it is low, then this overturning circulation is feeble, or has stopped altogether.

The signal from the deep ocean is that when they happen, these disruptions seem to happen very swiftly, and to linger for 100 years or more. And, the scientists say, these interruptions in the flow of the ocean – and with it, the transport of heat from the tropics – happen more easily than previously appreciated, and they occurred in past climate conditions similar to those the world may soon face.

“These findings suggest that our climate system, which depends greatly on deep ocean circulation, is critically poised near a tipping point for abrupt disruptions,” said Yair Rosenthal of Rutgers University in the US, one of the authors.

“Although the disruptions in circulation and possible coolings may be relatively short-lived – lasting maybe a century or more – the consequences might be large.” – Climate News Network

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

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