Tag Archives: Ice melt

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

Rivers flood, seas rise – and land faces erosion

Polar melting cannot be separated from farmland soil erosion and estuarine flooding. All are part of climate change.

LONDON, 7 September, 2020 – Climate heating often ensures that calamities don’t come singly: so don’t forget what erosion can do.

In a warmer world the glaciers will melt ever faster to raise global sea levels ever higher. In a wetter world, more and more topsoil will be swept off the farmlands and downriver into the ever-rising seas.

And the pay-off of silt-laden rivers and rising sea levels could be catastrophic floods, as swollen rivers suddenly change course. Since many of the world’s greatest cities are built on river estuaries, lives and economies will be at risk.

Three new studies in two journals deliver a sharp reminder that the consequences of global heating are not straightforward: the world responds to change in unpredictable ways.

First: the melting of the ice sheets and the mountain glaciers. Researchers warn in the journal Nature Climate Change that if the loss of ice from Antarctica, Greenland and the frozen rivers continues, then climate forecasters and government agencies will have to think again: sea levels could rise to at least 17cms higher than the worst predictions so far.

“Avulsions are the earthquakes of rivers. They are sudden and sometimes catastrophic. We are trying to understand where and when the next avulsions will occur”

That means an additional 16 million people at hazard from estuarine floods and storm surges.

In the last 30 years, the flow from the Antarctic ice cap has raised sea levels by 7.2mm, and from Greenland by 10.6mm. Every year, the world’s oceans are 4mm higher than they were the year before.

“Although we anticipated the ice sheets would lose increasing amounts of ice in response to the warming of the oceans and the atmosphere, the rate at which they are melting has accelerated faster than we could have imagined,” said Tom Slater of the University of Leeds, in the UK, who led the research.

“The melting is overtaking the climate models we use to guide us, and we are in danger of being unprepared for the risks posed by sea level rise.”

Dr Slater and his colleagues are the third team to warn in the last month that observations of climate already match the worst-case scenarios dreamed up by forecasters preparing for a range of possible climate outcomes.

Erosion risk rises

The latest reading of glacial melt rates suggests that the risk of storm surges for many of the world’s greatest cities will double by the close of the century. But coastal cities – and the farmers who already work 38% of the terrestrial surface to feed almost 8bn people – have another more immediate problem.

In a warmer world, more water evaporates. In a warmer atmosphere, the capacity of the air to hold moisture also increases, so along with more intense droughts, heavier rainfall is on the way for much of the world. And the heavier the rain, or the more prolonged the drought, the higher the risk of soil erosion.

In 2015 the world’s farmers and foresters watched 43 billion tonnes of topsoil wash away from hillsides or blow away from tilled land and into the sea. By 2070, this burden of silt swept away by water or blown by wind will have risen by between 30% and 66%: probably more than 28 bn tons of additional loss.

This could only impoverish the farmland, according to a study by Swiss scientists in the Proceedings of the National Academy of Sciences. It could also impoverish people, communities and countries. The worst hit could be in the less developed nations of the tropics and subtropics.

But the flow of ever-higher silt levels into ever-rising seas also raises a new hazard: hydrologists call it river avulsion. It’s a simple and natural process. As conditions change, so rivers will naturally change their flow to spill over new floodplains and extend coastal lands.

Survival in question

But river avulsions can also be helped along by rising sea levels. Since 10% of humanity is crowded into rich, fertile delta lands, and since some of the deadliest floods in human history – two in China in 1887 and 1931 claimed six million lives – have been caused by river avulsions, the question becomes a matter of life and death.

US scientists report, also in the Proceedings of the National Academy of Sciences, that rising sea levels alone could make abrupt river avulsion more probable, especially as delta lands could be subsiding, because of groundwater and other extraction.

The dangers of avulsion are affected by the rate of sediment deposit in the river channels, and this is likely to rise with sea levels. This in turn raises the level of the river and eventually a breach of a levee or other flood defence will force the river to find a swifter, steeper path to the sea.

Cities such as New Orleans and the coastal communities of the Mississippi delta are already vulnerable. “Avulsions are the earthquakes of rivers,” said Michael Lamb, of California Institute of Technology, one of the authors.

“They are sudden and sometimes catastrophic natural events that occur with statistical regularity, shifting the direction of major rivers. We are trying to understand where and when the next avulsions will occur.” – Climate News Network

Polar melting cannot be separated from farmland soil erosion and estuarine flooding. All are part of climate change.

LONDON, 7 September, 2020 – Climate heating often ensures that calamities don’t come singly: so don’t forget what erosion can do.

In a warmer world the glaciers will melt ever faster to raise global sea levels ever higher. In a wetter world, more and more topsoil will be swept off the farmlands and downriver into the ever-rising seas.

And the pay-off of silt-laden rivers and rising sea levels could be catastrophic floods, as swollen rivers suddenly change course. Since many of the world’s greatest cities are built on river estuaries, lives and economies will be at risk.

Three new studies in two journals deliver a sharp reminder that the consequences of global heating are not straightforward: the world responds to change in unpredictable ways.

First: the melting of the ice sheets and the mountain glaciers. Researchers warn in the journal Nature Climate Change that if the loss of ice from Antarctica, Greenland and the frozen rivers continues, then climate forecasters and government agencies will have to think again: sea levels could rise to at least 17cms higher than the worst predictions so far.

“Avulsions are the earthquakes of rivers. They are sudden and sometimes catastrophic. We are trying to understand where and when the next avulsions will occur”

That means an additional 16 million people at hazard from estuarine floods and storm surges.

In the last 30 years, the flow from the Antarctic ice cap has raised sea levels by 7.2mm, and from Greenland by 10.6mm. Every year, the world’s oceans are 4mm higher than they were the year before.

“Although we anticipated the ice sheets would lose increasing amounts of ice in response to the warming of the oceans and the atmosphere, the rate at which they are melting has accelerated faster than we could have imagined,” said Tom Slater of the University of Leeds, in the UK, who led the research.

“The melting is overtaking the climate models we use to guide us, and we are in danger of being unprepared for the risks posed by sea level rise.”

Dr Slater and his colleagues are the third team to warn in the last month that observations of climate already match the worst-case scenarios dreamed up by forecasters preparing for a range of possible climate outcomes.

Erosion risk rises

The latest reading of glacial melt rates suggests that the risk of storm surges for many of the world’s greatest cities will double by the close of the century. But coastal cities – and the farmers who already work 38% of the terrestrial surface to feed almost 8bn people – have another more immediate problem.

In a warmer world, more water evaporates. In a warmer atmosphere, the capacity of the air to hold moisture also increases, so along with more intense droughts, heavier rainfall is on the way for much of the world. And the heavier the rain, or the more prolonged the drought, the higher the risk of soil erosion.

In 2015 the world’s farmers and foresters watched 43 billion tonnes of topsoil wash away from hillsides or blow away from tilled land and into the sea. By 2070, this burden of silt swept away by water or blown by wind will have risen by between 30% and 66%: probably more than 28 bn tons of additional loss.

This could only impoverish the farmland, according to a study by Swiss scientists in the Proceedings of the National Academy of Sciences. It could also impoverish people, communities and countries. The worst hit could be in the less developed nations of the tropics and subtropics.

But the flow of ever-higher silt levels into ever-rising seas also raises a new hazard: hydrologists call it river avulsion. It’s a simple and natural process. As conditions change, so rivers will naturally change their flow to spill over new floodplains and extend coastal lands.

Survival in question

But river avulsions can also be helped along by rising sea levels. Since 10% of humanity is crowded into rich, fertile delta lands, and since some of the deadliest floods in human history – two in China in 1887 and 1931 claimed six million lives – have been caused by river avulsions, the question becomes a matter of life and death.

US scientists report, also in the Proceedings of the National Academy of Sciences, that rising sea levels alone could make abrupt river avulsion more probable, especially as delta lands could be subsiding, because of groundwater and other extraction.

The dangers of avulsion are affected by the rate of sediment deposit in the river channels, and this is likely to rise with sea levels. This in turn raises the level of the river and eventually a breach of a levee or other flood defence will force the river to find a swifter, steeper path to the sea.

Cities such as New Orleans and the coastal communities of the Mississippi delta are already vulnerable. “Avulsions are the earthquakes of rivers,” said Michael Lamb, of California Institute of Technology, one of the authors.

“They are sudden and sometimes catastrophic natural events that occur with statistical regularity, shifting the direction of major rivers. We are trying to understand where and when the next avulsions will occur.” – 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

End of Arctic sea ice by 2035 possible, study finds

How soon will the northern polar ocean be ice-free? New research expects the end of Arctic sea ice by 2035.

LONDON, 11 August, 2020 − The temperature of the Arctic matters to the entire world: it helps to keep the global climate fairly cool. Scientists now say that by 2035 there could be an end to Arctic sea ice.

The northern polar ocean’s sea ice is a crucial element in the Earth system: because it is highly reflective, it sends solar radiation back out into space. Once it’s melted, there’s no longer any protection for the darker water and rock beneath, and nothing to prevent them absorbing the incoming heat.

High temperatures in the Arctic during the last interglacial – the warm period around 127,000 years ago – have puzzled scientists for decades.

Now the UK Met Office’s Hadley Centre climate model has enabled an international research team to compare Arctic sea ice conditions during the last interglacial with the present day. Their findings are important for improving predictions of future sea ice change.

What is striking about the latest research is the date it suggests for a possible total melt − 2035. Many studies have thought a mid-century crisis likely, with another even carefully specifying 2044 as the year to watch. So a breathing space of only 15 years may surprise some experts.

“The prospect of loss of sea ice by 2035 should really be focussing all our minds on achieving a low-carbon world as soon as humanly feasible”

During spring and early summer shallow pools of water form on the surface of the Arctic sea ice. These “melt ponds” help to determine how much sunlight is absorbed by the ice and how much is reflected back into space. The new Hadley Centre model is the UK’s most advanced physical representation of the Earth’s climate and a critical tool for climate research, and it incorporates sea ice and melt ponds.

The researchers report their findings in the journal Nature Climate Change. Using the model to look at Arctic sea ice during the last interglacial, they concluded that the impact of intense springtime sunshine created many melt ponds, which played a crucial role in sea ice melt. A simulation of the future using the same model indicates that the Arctic may become sea ice-free by 2035.

The joint lead author of the team is Dr Maria Vittoria Guarino, an earth system modeller at the British Antarctic Survey (BAS) in Cambridge. She says: “High temperatures in the Arctic have puzzled scientists for decades. Unravelling this mystery was technically and scientifically challenging. For the first time, we can begin to see how the Arctic became sea ice-free during the last interglacial.

“The advances made in climate modelling mean that we can create a more accurate simulation of the Earth’s past climate which, in turn, gives us greater confidence in model predictions for the future.”

Dr Louise Sime, the group head of the palaeoclimate group and joint lead author at BAS, says: “We know the Arctic is undergoing significant changes as our planet warms. By understanding what happened during Earth’s last warm period we are in a better position to understand what will happen in the future.

Melt ponds crucial

“The prospect of loss of sea ice by 2035 should really be focussing all our minds on achieving a low-carbon world as soon as humanly feasible.”

Dr David Schroeder from the University of Reading, UK, who co-led the implementation of the melt pond scheme in the climate model, says: “This shows just how important sea ice processes like melt ponds are in the Arctic, and why it is crucial that they are incorporated into climate models.”

The extent of the areas sea ice covers varies between summer and winter. If more solar energy is absorbed at the surface, and temperatures rise further, a cycle of warming and melting occurs during summer months.

When the ice forms, the ocean water beneath becomes saltier and denser than the surrounding ocean. Saltier water sinks and moves along the ocean bottom towards the equator, while warm water from mid-depths to the surface travels from the equator towards the poles.

Scientists refer to this process as the ocean’s global “conveyor-belt”. Changes to the volume of sea ice can disrupt normal ocean circulation, with consequences for global climate. − Climate News Network

How soon will the northern polar ocean be ice-free? New research expects the end of Arctic sea ice by 2035.

LONDON, 11 August, 2020 − The temperature of the Arctic matters to the entire world: it helps to keep the global climate fairly cool. Scientists now say that by 2035 there could be an end to Arctic sea ice.

The northern polar ocean’s sea ice is a crucial element in the Earth system: because it is highly reflective, it sends solar radiation back out into space. Once it’s melted, there’s no longer any protection for the darker water and rock beneath, and nothing to prevent them absorbing the incoming heat.

High temperatures in the Arctic during the last interglacial – the warm period around 127,000 years ago – have puzzled scientists for decades.

Now the UK Met Office’s Hadley Centre climate model has enabled an international research team to compare Arctic sea ice conditions during the last interglacial with the present day. Their findings are important for improving predictions of future sea ice change.

What is striking about the latest research is the date it suggests for a possible total melt − 2035. Many studies have thought a mid-century crisis likely, with another even carefully specifying 2044 as the year to watch. So a breathing space of only 15 years may surprise some experts.

“The prospect of loss of sea ice by 2035 should really be focussing all our minds on achieving a low-carbon world as soon as humanly feasible”

During spring and early summer shallow pools of water form on the surface of the Arctic sea ice. These “melt ponds” help to determine how much sunlight is absorbed by the ice and how much is reflected back into space. The new Hadley Centre model is the UK’s most advanced physical representation of the Earth’s climate and a critical tool for climate research, and it incorporates sea ice and melt ponds.

The researchers report their findings in the journal Nature Climate Change. Using the model to look at Arctic sea ice during the last interglacial, they concluded that the impact of intense springtime sunshine created many melt ponds, which played a crucial role in sea ice melt. A simulation of the future using the same model indicates that the Arctic may become sea ice-free by 2035.

The joint lead author of the team is Dr Maria Vittoria Guarino, an earth system modeller at the British Antarctic Survey (BAS) in Cambridge. She says: “High temperatures in the Arctic have puzzled scientists for decades. Unravelling this mystery was technically and scientifically challenging. For the first time, we can begin to see how the Arctic became sea ice-free during the last interglacial.

“The advances made in climate modelling mean that we can create a more accurate simulation of the Earth’s past climate which, in turn, gives us greater confidence in model predictions for the future.”

Dr Louise Sime, the group head of the palaeoclimate group and joint lead author at BAS, says: “We know the Arctic is undergoing significant changes as our planet warms. By understanding what happened during Earth’s last warm period we are in a better position to understand what will happen in the future.

Melt ponds crucial

“The prospect of loss of sea ice by 2035 should really be focussing all our minds on achieving a low-carbon world as soon as humanly feasible.”

Dr David Schroeder from the University of Reading, UK, who co-led the implementation of the melt pond scheme in the climate model, says: “This shows just how important sea ice processes like melt ponds are in the Arctic, and why it is crucial that they are incorporated into climate models.”

The extent of the areas sea ice covers varies between summer and winter. If more solar energy is absorbed at the surface, and temperatures rise further, a cycle of warming and melting occurs during summer months.

When the ice forms, the ocean water beneath becomes saltier and denser than the surrounding ocean. Saltier water sinks and moves along the ocean bottom towards the equator, while warm water from mid-depths to the surface travels from the equator towards the poles.

Scientists refer to this process as the ocean’s global “conveyor-belt”. Changes to the volume of sea ice can disrupt normal ocean circulation, with consequences for global climate. − Climate News Network

Food shortage may finish polar bears by 2100

How long polar bears can survive depends on how long they can last without food. And that may be: not long enough.

LONDON, 24 July, 2020 − As the Arctic sea ice dwindles, so will hope for the region’s most dramatic predator, its polar bears. A creature fashioned by evolution to fast a whole summer and gorge through the autumn and winter may not last, as the ice melts ever earlier and forms ever later.

That is because Ursus maritimus can find the food for the next generation of its cubs only by prowling the firm sea ice for a high-calorie diet of seal flesh and blubber.

And now a team of Canadian and US scientists has begun to establish the unknown of polar bear survival: how many days the creature can survive without food and still nourish its young and sustain life.

They call this the “fasting impact threshold” and the answer, they report in the journal Nature Climate Change, is not encouraging.

“Polar bears everywhere will face longer periods without food, and this will affect their ability to reproduce, survive and persist”

If warming continues at the present rate, then by the century’s end most of the sub-populations of this charismatic animal will not survive.

“The challenge is that the Arctic ice will keep disappearing as the world continues to warm,” said Péter Molnár, of the University of Toronto Scarborough, who led the research.

“This means polar bears everywhere will face longer periods without food, and this will affect their ability to reproduce, survive and persist as healthy populations.”

The researchers had to start with one big uncertainty: how much stored energy the bear has when the fasting season begins. Because the shelf ice has been thinning and shrinking for more than 40 years, hunting seasons have become shorter and bears now spend longer and longer on land.

Natural variability

That raised a second factor: some parts of the Arctic lose ice earlier than others. The third unknown is the health of the 19 sub-populations of Ursus maritimus, spread over four distinct eco-regions within the Arctic Circle, and how these separate populations would consider a “good” hunting season and a happy period of fasting.

In the southern Beaufort Sea, fewer than 127 ice-free days could be considered “good”, but even this seemingly assured number was based on only five years of systematic demographic data.

And then the researchers had to calculate the demands placed on individual bears: an adult male might be able to last 200 days; a solitary adult female up to 255 days. But a mother bear might begin to lose what it takes to get cubs through to maturity as early as 117 days, and certainly after 228 days.

But however incomplete, the scientists had data for about 80% of the polar bear populations, collected between 1979 and 2016, and report that what they politely call “recruitment and survival impact thresholds” may have already been exceeded in some populations.

Too hopeful?

That is, there are increasing numbers of bears in the Arctic no longer sure of having cubs or keeping them alive. That includes the polar bears of Hudson Bay and the Davis Strait in northern Canada: perhaps the most photographed bears in the world.

And if the world goes on warming, only a few creatures in the very high Arctic will see the next century.

“While our projections for the future of polar bears seem dire, the unfortunate thing is they might even be too optimistic. For example, we assumed that polar bears will use their available body energy in optimal ways when fasting. If that isn’t the case, the reality could be worse than our projections,” Dr Molnár said.

“What we do know is that becoming fat before a fasting season will be more difficult for polar bears as on-ice hunting seasons become shorter, so it’s likely that fasting impact thresholds will be crossed in the early years of our projected range.” − Climate News Network

How long polar bears can survive depends on how long they can last without food. And that may be: not long enough.

LONDON, 24 July, 2020 − As the Arctic sea ice dwindles, so will hope for the region’s most dramatic predator, its polar bears. A creature fashioned by evolution to fast a whole summer and gorge through the autumn and winter may not last, as the ice melts ever earlier and forms ever later.

That is because Ursus maritimus can find the food for the next generation of its cubs only by prowling the firm sea ice for a high-calorie diet of seal flesh and blubber.

And now a team of Canadian and US scientists has begun to establish the unknown of polar bear survival: how many days the creature can survive without food and still nourish its young and sustain life.

They call this the “fasting impact threshold” and the answer, they report in the journal Nature Climate Change, is not encouraging.

“Polar bears everywhere will face longer periods without food, and this will affect their ability to reproduce, survive and persist”

If warming continues at the present rate, then by the century’s end most of the sub-populations of this charismatic animal will not survive.

“The challenge is that the Arctic ice will keep disappearing as the world continues to warm,” said Péter Molnár, of the University of Toronto Scarborough, who led the research.

“This means polar bears everywhere will face longer periods without food, and this will affect their ability to reproduce, survive and persist as healthy populations.”

The researchers had to start with one big uncertainty: how much stored energy the bear has when the fasting season begins. Because the shelf ice has been thinning and shrinking for more than 40 years, hunting seasons have become shorter and bears now spend longer and longer on land.

Natural variability

That raised a second factor: some parts of the Arctic lose ice earlier than others. The third unknown is the health of the 19 sub-populations of Ursus maritimus, spread over four distinct eco-regions within the Arctic Circle, and how these separate populations would consider a “good” hunting season and a happy period of fasting.

In the southern Beaufort Sea, fewer than 127 ice-free days could be considered “good”, but even this seemingly assured number was based on only five years of systematic demographic data.

And then the researchers had to calculate the demands placed on individual bears: an adult male might be able to last 200 days; a solitary adult female up to 255 days. But a mother bear might begin to lose what it takes to get cubs through to maturity as early as 117 days, and certainly after 228 days.

But however incomplete, the scientists had data for about 80% of the polar bear populations, collected between 1979 and 2016, and report that what they politely call “recruitment and survival impact thresholds” may have already been exceeded in some populations.

Too hopeful?

That is, there are increasing numbers of bears in the Arctic no longer sure of having cubs or keeping them alive. That includes the polar bears of Hudson Bay and the Davis Strait in northern Canada: perhaps the most photographed bears in the world.

And if the world goes on warming, only a few creatures in the very high Arctic will see the next century.

“While our projections for the future of polar bears seem dire, the unfortunate thing is they might even be too optimistic. For example, we assumed that polar bears will use their available body energy in optimal ways when fasting. If that isn’t the case, the reality could be worse than our projections,” Dr Molnár said.

“What we do know is that becoming fat before a fasting season will be more difficult for polar bears as on-ice hunting seasons become shorter, so it’s likely that fasting impact thresholds will be crossed in the early years of our projected range.” − Climate News Network

Human climate change causes Arctic’s record heat

The coldest place in the Arctic has experienced record heat. Climate change has made this 600 times more probable.

LONDON, 23 July, 2020 – An international team of scientists has pinned the strange weather and record heat in the Siberian Arctic firmly on human-induced climate change.

On average, from January to June, temperatures in the region have been 5°C hotter because the world’s cities have continued to consume ever-increasing levels of fossil fuels.

The researchers report that, without human help, such freak conditions could happen only once every 80,000 years or so. But a steady increase in greenhouse gas levels in the atmosphere for the last century or more has increased the chances of record temperatures – one Arctic Circle settlement, Verkhoyansk, normally one of the coldest places on Earth, recorded 38°C on 20 June – by a factor of 600.

“The findings of this rapid research – that climate change increased the chances of prolonged heat in Siberia by at least 600 times – are truly staggering,” said Andrew Ciavarella, of the UK Met Office, who led the study.

“This research is further evidence of the extreme temperatures we can expect to see more frequently around the world in a warming global climate. Importantly, an increasing frequency of these extreme heat events can be moderated by reducing greenhouse gas emissions.”

Confidence grows

That climate change has come to the Arctic is not news: what is significant about the research by British, French, Swiss, Dutch, German and Russian meteorologists is the readiness to put the blame fairly on climate change, even for a freak event.

It has always been a given in the science that the mix of air pressure and temperatures around the world delivers a random pattern of change marked by extremes, and for decades scientists backed away from blaming any single flood, windstorm or heat wave as evidence of climate change. That has, in the last few years, changed.

Research teams have successively warned that climate change driven by human action had contributed to California’s most recent disastrous drought; that both calamitous floods and catastrophic bushfires in Australia were made more probable and more intense by rising greenhouse gas emissions; and that the signature of climate change driven by fossil fuel combustion was now detectable in daily weather changes almost anywhere around the globe.

But the signature of climate change in the Siberian Arctic has been pronounced, and the latest attribution study is confirmation of a new confidence in the data.

“The findings of this rapid research – that climate change increased the chances of prolonged heat in Siberia by at least 600 times – are truly staggering”

In June, forest fires in Siberia consumed 1.15 million hectares and released about 56 million tonnes of carbon dioxide: this is more than the annual emissions from Switzerland or Norway.

The rising temperatures in the region have been grounds for extra alarm: permafrost in the Arctic Circle is a store of carbon that is increasingly being released as the ground thaws, to make Arctic warming even worse.

But the hazards of permafrost thaw are also direct: soils become more vulnerable to slip and slump, and there is already measurable damage to the infrastructure once supported by sediments and topsoils that used to be frozen solid all year round.

The region recorded one of the world’s worst oil spills in May, when an oil tank collapsed. The unseasonal and improbable heat has been coupled to an explosion of silk moths, bringing further caterpillar damage to conifer forests.

Even now such temperatures remain unlikely: the human component of climate change has simply reduced the frequency of such sustained temperatures to perhaps once every 135 years.

Little time left

But without rapid and drastic cuts worldwide in greenhouse gas emissions, towns like Verkhoyansk – which also shares the record for the coldest temperature in the northern hemisphere – could become a lot warmer, a lot more often before the century’s end.

“These results show that we are starting to experience extreme events which have almost no chance of happening without a human footprint on the climate system,” said Sonia Seneviratne, of the Swiss Federal Institute of Technology, known as ETH Zurich.

“We have little time left to stabilise global warming at levels at which climate change would lie within the bounds of the Paris Agreement.

“For a stabilisation at 1.5°C of global warming, which would still imply risks of such extreme heat events, we need to reduce our CO2 emissions by at least half until 2030.” – Climate News Network

The coldest place in the Arctic has experienced record heat. Climate change has made this 600 times more probable.

LONDON, 23 July, 2020 – An international team of scientists has pinned the strange weather and record heat in the Siberian Arctic firmly on human-induced climate change.

On average, from January to June, temperatures in the region have been 5°C hotter because the world’s cities have continued to consume ever-increasing levels of fossil fuels.

The researchers report that, without human help, such freak conditions could happen only once every 80,000 years or so. But a steady increase in greenhouse gas levels in the atmosphere for the last century or more has increased the chances of record temperatures – one Arctic Circle settlement, Verkhoyansk, normally one of the coldest places on Earth, recorded 38°C on 20 June – by a factor of 600.

“The findings of this rapid research – that climate change increased the chances of prolonged heat in Siberia by at least 600 times – are truly staggering,” said Andrew Ciavarella, of the UK Met Office, who led the study.

“This research is further evidence of the extreme temperatures we can expect to see more frequently around the world in a warming global climate. Importantly, an increasing frequency of these extreme heat events can be moderated by reducing greenhouse gas emissions.”

Confidence grows

That climate change has come to the Arctic is not news: what is significant about the research by British, French, Swiss, Dutch, German and Russian meteorologists is the readiness to put the blame fairly on climate change, even for a freak event.

It has always been a given in the science that the mix of air pressure and temperatures around the world delivers a random pattern of change marked by extremes, and for decades scientists backed away from blaming any single flood, windstorm or heat wave as evidence of climate change. That has, in the last few years, changed.

Research teams have successively warned that climate change driven by human action had contributed to California’s most recent disastrous drought; that both calamitous floods and catastrophic bushfires in Australia were made more probable and more intense by rising greenhouse gas emissions; and that the signature of climate change driven by fossil fuel combustion was now detectable in daily weather changes almost anywhere around the globe.

But the signature of climate change in the Siberian Arctic has been pronounced, and the latest attribution study is confirmation of a new confidence in the data.

“The findings of this rapid research – that climate change increased the chances of prolonged heat in Siberia by at least 600 times – are truly staggering”

In June, forest fires in Siberia consumed 1.15 million hectares and released about 56 million tonnes of carbon dioxide: this is more than the annual emissions from Switzerland or Norway.

The rising temperatures in the region have been grounds for extra alarm: permafrost in the Arctic Circle is a store of carbon that is increasingly being released as the ground thaws, to make Arctic warming even worse.

But the hazards of permafrost thaw are also direct: soils become more vulnerable to slip and slump, and there is already measurable damage to the infrastructure once supported by sediments and topsoils that used to be frozen solid all year round.

The region recorded one of the world’s worst oil spills in May, when an oil tank collapsed. The unseasonal and improbable heat has been coupled to an explosion of silk moths, bringing further caterpillar damage to conifer forests.

Even now such temperatures remain unlikely: the human component of climate change has simply reduced the frequency of such sustained temperatures to perhaps once every 135 years.

Little time left

But without rapid and drastic cuts worldwide in greenhouse gas emissions, towns like Verkhoyansk – which also shares the record for the coldest temperature in the northern hemisphere – could become a lot warmer, a lot more often before the century’s end.

“These results show that we are starting to experience extreme events which have almost no chance of happening without a human footprint on the climate system,” said Sonia Seneviratne, of the Swiss Federal Institute of Technology, known as ETH Zurich.

“We have little time left to stabilise global warming at levels at which climate change would lie within the bounds of the Paris Agreement.

“For a stabilisation at 1.5°C of global warming, which would still imply risks of such extreme heat events, we need to reduce our CO2 emissions by at least half until 2030.” – Climate News Network

Arctic Ocean is set for more turbulent future

The Arctic Ocean is about to become more violent, with higher storm waves and higher frequency, across a wide region.

LONDON, 20 July, 2020 − The Arctic Ocean is changing, and changing fast. By the century’s end, the maximum height of storm waves in the polar seas could have risen by twice or even three times the present height.

According to new research, wave heights could increase by two metres and coastal floods could become four times, or even 10 times, as frequent.

And a separate study has found that even the character of the water in the ocean is changing: warm salty water from the Atlantic is weakening the ice cover at an accelerating rate, but providing more nutrients for Arctic life, while extra river water from the Pacific has made the American-Asian part of the Arctic Ocean less likely to mix, and less biologically productive.

The Arctic is warming at twice the rate of the planet as a whole: the ice cover has been thinning and retreating for decades. And temperatures keep on rising.

One Siberian town recorded a temperature of 38°C in June, and the region has been hit by devastating forest fires.

“In many respects, the Arctic Ocean now looks like a new ocean”

And as the oceans warm, winds become more powerful and the ocean waves respond, with prospects of ever-greater hazard for shipping and coastal settlements.

Extreme wave events that once occurred in the Arctic at average intervals of once every 20 years could by the end of the century happen every two to five years, according a study in the Journal of Geophysical Research: Oceans.

“It increases the risk of flooding and erosion. It increases drastically almost everywhere”, said Mercè Casas-Prat, a researcher with Environment and Climate Change Canada. “This can have a direct impact on communities that live close to the shoreline.”

She and a colleague used computer simulations and a range of climate predictions to work out what will happen to those ocean surfaces not covered by ice as the seas warm in response to greenhouse gas emissions from fossil fuel combustion.

They found that almost everywhere in the Arctic would experience greater wave height. The hardest-hit would be the Greenland Sea, bounded by the largest body of ice in the northern hemisphere, and the Svalbard Archipelago.

More salty water

Maximum annual wave heights could increase by as much as six metres.
“At the end of the century, the maximum will on average come later in the year and also be more extreme,” Dr Casas-Prat said.

The Arctic Ocean covers only about 3% of the planet’s surface, but it is vulnerable to change in ocean regions much nearer the Equator. US and Scandinavian scientists report in the journal Frontiers in Marine Science that they looked at 37 years of direct observation and measurement to find that not only are Arctic waters changing: they are changing in different ways.

Flows of increasingly warm salty water from the Atlantic have begun to mix at depth, weaken sea ice and bring deeper, nutrient-rich water to the surface. At the other entrance to the partly landlocked expanse of water, an increasing flow from rivers has begun to make the separation of surface and deep layers even more pronounced.

This limits the movement of nutrients to the surface, protentially making that part of the sea less biologically rich. Many marine creatures from low latitudes are moving north, in some cases replacing local species. The changes could affect fisheries, tourism, navigation and of course the people who live in the Arctic.

“In many respects, the Arctic Ocean now looks like a new ocean,” said Igor Polyakov, an oceanographer at the University of Fairbanks, Alaska, who led the research. − Climate News Network

The Arctic Ocean is about to become more violent, with higher storm waves and higher frequency, across a wide region.

LONDON, 20 July, 2020 − The Arctic Ocean is changing, and changing fast. By the century’s end, the maximum height of storm waves in the polar seas could have risen by twice or even three times the present height.

According to new research, wave heights could increase by two metres and coastal floods could become four times, or even 10 times, as frequent.

And a separate study has found that even the character of the water in the ocean is changing: warm salty water from the Atlantic is weakening the ice cover at an accelerating rate, but providing more nutrients for Arctic life, while extra river water from the Pacific has made the American-Asian part of the Arctic Ocean less likely to mix, and less biologically productive.

The Arctic is warming at twice the rate of the planet as a whole: the ice cover has been thinning and retreating for decades. And temperatures keep on rising.

One Siberian town recorded a temperature of 38°C in June, and the region has been hit by devastating forest fires.

“In many respects, the Arctic Ocean now looks like a new ocean”

And as the oceans warm, winds become more powerful and the ocean waves respond, with prospects of ever-greater hazard for shipping and coastal settlements.

Extreme wave events that once occurred in the Arctic at average intervals of once every 20 years could by the end of the century happen every two to five years, according a study in the Journal of Geophysical Research: Oceans.

“It increases the risk of flooding and erosion. It increases drastically almost everywhere”, said Mercè Casas-Prat, a researcher with Environment and Climate Change Canada. “This can have a direct impact on communities that live close to the shoreline.”

She and a colleague used computer simulations and a range of climate predictions to work out what will happen to those ocean surfaces not covered by ice as the seas warm in response to greenhouse gas emissions from fossil fuel combustion.

They found that almost everywhere in the Arctic would experience greater wave height. The hardest-hit would be the Greenland Sea, bounded by the largest body of ice in the northern hemisphere, and the Svalbard Archipelago.

More salty water

Maximum annual wave heights could increase by as much as six metres.
“At the end of the century, the maximum will on average come later in the year and also be more extreme,” Dr Casas-Prat said.

The Arctic Ocean covers only about 3% of the planet’s surface, but it is vulnerable to change in ocean regions much nearer the Equator. US and Scandinavian scientists report in the journal Frontiers in Marine Science that they looked at 37 years of direct observation and measurement to find that not only are Arctic waters changing: they are changing in different ways.

Flows of increasingly warm salty water from the Atlantic have begun to mix at depth, weaken sea ice and bring deeper, nutrient-rich water to the surface. At the other entrance to the partly landlocked expanse of water, an increasing flow from rivers has begun to make the separation of surface and deep layers even more pronounced.

This limits the movement of nutrients to the surface, protentially making that part of the sea less biologically rich. Many marine creatures from low latitudes are moving north, in some cases replacing local species. The changes could affect fisheries, tourism, navigation and of course the people who live in the Arctic.

“In many respects, the Arctic Ocean now looks like a new ocean,” said Igor Polyakov, an oceanographer at the University of Fairbanks, Alaska, who led the research. − Climate News Network

Antarctic melting could bring a much hotter future

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

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

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

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

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

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

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

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

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

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

Tell-tale line

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

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

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

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

Faster change ahead

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Tell-tale line

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

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

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

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

Faster change ahead

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

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

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

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

Siberia dries out as forests burn and climate heats

A huge swathe of Arctic Russia is changing rapidly as oil leaks, the climate warms and Siberia dries out.

LONDON, 5 June, 2020 – Residents of the small Arctic town of Khatanga have never experienced anything like it: their home is changing at a gallop as Siberia dries out.

Khatanga – population around 3,500 – is well north of the Arctic Circle, with usual daytime temperatures at this time of year hovering round a chilly 0°C. On 22 May the temperature in the town reached 25°C – more than double the record to date.

Global warming is causing profound change across the Arctic, a region which acts like a giant air conditioning system regulating the Earth’s climate.

Temperatures are rising far faster than elsewhere: sea ice cover is rapidly disappearing, valuable fish stocks are moving ever further north in search of colder waters, land around the Arctic perimeter is drying out – particularly across the vast expanse of Siberia.

Permafrost is melting. This week a giant oil tank collapsed and ruptured at a nickel and palladium works near the city of Norilsk in northern Siberia, spilling thousands of tonnes of diesel into the nearby Ambarnaya river.

Worst for years

The storage tank is believed to have been built on permafrost: a state of emergency has been declared for what is being described as one of the worst environmental disasters in recent Russian history. State media say an area stretching over 350 square kilometres is polluted and will take years to clean up.

A series of wildfires, often enveloping hundreds of thousands of hectares of Siberia’s boreal forests, or taiga, have raged in many areas over recent weeks.

In early spring farmers across Siberia often light fires to clear land of dead grass and unwanted vegetation. A combination of high temperatures and strong winds has led to fires blazing out of control. Last year Siberia’s fires are estimated to have destroyed an area of forest the size of Belgium.

“2019 saw a record number of fires over the summer months in Siberia”, says Thomas Smith, an environmental geographer at the London School of Economics (LSE) and a wildfires expert.

“This year, aided by high temperatures and conditions that have promoted growth, the fires started early, though so far their incidence is about average and not as extensive as in 2019.

“Forest fires in this region of the Arctic used to happen about every hundred years and now we’re seeing them every summer”

“But what’s important are the peak summer months: the soils are dry and there’s plenty of fuel, so conditions are favourable for more widespread fires”, Dr Smith told Climate News Network.

One of the regions worst affected is in the south of Siberia, around Lake Baikal, the world’s largest and deepest freshwater lake, where an estimated half a million hectares of forest were destroyed by fire earlier this year.

Evgeny Zinichev, Russia’s emergencies minister, speaks of a critical situation unfolding in Siberia and across Russia’s Far East. “The main reason, of course, is unauthorised and uncontrolled agricultural fires”, he says.

“A less snowy winter, an abnormal winter, and insufficient soil moisture are factors that create the conditions for the transition of landscape fires to settlements.”

Other factors have also led to the spread of wildfires. After weeks of lockdown due to the Covid-19 pandemic, people trapped in often cramped and stiflingly hot apartment blocks have sought freedom in the countryside and forests, camping and lighting barbecues.

Hungry Chinese demand

In Soviet times the taiga was more closely monitored and policed: that system has tended to break down in recent years. The Covid crisis has also drawn attention away from the fires.

Corruption and illegal logging, driven in large part by China’s demand for forest products, is an additional threat to the taiga.

The warming and wildfires are having an impact not only across Siberia but around the world. Its forests act as an enormous carbon sink, storing millions of tonnes of climate-changing greenhouse gases.

Fires and logging release the gases into the atmosphere, creating what scientists call a positive feedback loop – the more gases that are released, the warmer and drier the air becomes, so that more areas of forest are at risk from fire.

“Substantial areas of forest in Siberia are on peat soils”, says Dr Smith. “When these soils dry out, fires go underground, threatening to release large amounts of carbon which can lead to a catastrophic climate event.”

Wide impact

Smoke from the fires is carried by winds to other parts of the globe, trapping warm air near the Earth’s surface. The warm air generated by the fires is also likely to result in a further depletion in ice cover and warming of the Arctic seas.

The temperature rises and the growing incidence of wildfires in Siberia have other effects too.

A recent study published in the journal Scientific Reports says the fires mean that more nutrients, particularly nitrogen, leak into streams and waterways.

“Forest fires in this region of the Arctic used to happen about every hundred years and now we’re seeing them every summer”, says Bianca Rodriguez-Cardona, of the University of New Hampshire, Durham, US, one of the study’s authors.

“This increase in fires leads to more input of inorganic solutes into local streams which can alter the chemistry and trigger issues like increased algal blooms and bacteria that can be harmful to humans who depend on these waterways for drinking water, fishing and their livelihoods.” When these waters reach the Arctic they can also dramatically alter the chemistry of the surrounding seas, says the study. – Climate News Network

A huge swathe of Arctic Russia is changing rapidly as oil leaks, the climate warms and Siberia dries out.

LONDON, 5 June, 2020 – Residents of the small Arctic town of Khatanga have never experienced anything like it: their home is changing at a gallop as Siberia dries out.

Khatanga – population around 3,500 – is well north of the Arctic Circle, with usual daytime temperatures at this time of year hovering round a chilly 0°C. On 22 May the temperature in the town reached 25°C – more than double the record to date.

Global warming is causing profound change across the Arctic, a region which acts like a giant air conditioning system regulating the Earth’s climate.

Temperatures are rising far faster than elsewhere: sea ice cover is rapidly disappearing, valuable fish stocks are moving ever further north in search of colder waters, land around the Arctic perimeter is drying out – particularly across the vast expanse of Siberia.

Permafrost is melting. This week a giant oil tank collapsed and ruptured at a nickel and palladium works near the city of Norilsk in northern Siberia, spilling thousands of tonnes of diesel into the nearby Ambarnaya river.

Worst for years

The storage tank is believed to have been built on permafrost: a state of emergency has been declared for what is being described as one of the worst environmental disasters in recent Russian history. State media say an area stretching over 350 square kilometres is polluted and will take years to clean up.

A series of wildfires, often enveloping hundreds of thousands of hectares of Siberia’s boreal forests, or taiga, have raged in many areas over recent weeks.

In early spring farmers across Siberia often light fires to clear land of dead grass and unwanted vegetation. A combination of high temperatures and strong winds has led to fires blazing out of control. Last year Siberia’s fires are estimated to have destroyed an area of forest the size of Belgium.

“2019 saw a record number of fires over the summer months in Siberia”, says Thomas Smith, an environmental geographer at the London School of Economics (LSE) and a wildfires expert.

“This year, aided by high temperatures and conditions that have promoted growth, the fires started early, though so far their incidence is about average and not as extensive as in 2019.

“Forest fires in this region of the Arctic used to happen about every hundred years and now we’re seeing them every summer”

“But what’s important are the peak summer months: the soils are dry and there’s plenty of fuel, so conditions are favourable for more widespread fires”, Dr Smith told Climate News Network.

One of the regions worst affected is in the south of Siberia, around Lake Baikal, the world’s largest and deepest freshwater lake, where an estimated half a million hectares of forest were destroyed by fire earlier this year.

Evgeny Zinichev, Russia’s emergencies minister, speaks of a critical situation unfolding in Siberia and across Russia’s Far East. “The main reason, of course, is unauthorised and uncontrolled agricultural fires”, he says.

“A less snowy winter, an abnormal winter, and insufficient soil moisture are factors that create the conditions for the transition of landscape fires to settlements.”

Other factors have also led to the spread of wildfires. After weeks of lockdown due to the Covid-19 pandemic, people trapped in often cramped and stiflingly hot apartment blocks have sought freedom in the countryside and forests, camping and lighting barbecues.

Hungry Chinese demand

In Soviet times the taiga was more closely monitored and policed: that system has tended to break down in recent years. The Covid crisis has also drawn attention away from the fires.

Corruption and illegal logging, driven in large part by China’s demand for forest products, is an additional threat to the taiga.

The warming and wildfires are having an impact not only across Siberia but around the world. Its forests act as an enormous carbon sink, storing millions of tonnes of climate-changing greenhouse gases.

Fires and logging release the gases into the atmosphere, creating what scientists call a positive feedback loop – the more gases that are released, the warmer and drier the air becomes, so that more areas of forest are at risk from fire.

“Substantial areas of forest in Siberia are on peat soils”, says Dr Smith. “When these soils dry out, fires go underground, threatening to release large amounts of carbon which can lead to a catastrophic climate event.”

Wide impact

Smoke from the fires is carried by winds to other parts of the globe, trapping warm air near the Earth’s surface. The warm air generated by the fires is also likely to result in a further depletion in ice cover and warming of the Arctic seas.

The temperature rises and the growing incidence of wildfires in Siberia have other effects too.

A recent study published in the journal Scientific Reports says the fires mean that more nutrients, particularly nitrogen, leak into streams and waterways.

“Forest fires in this region of the Arctic used to happen about every hundred years and now we’re seeing them every summer”, says Bianca Rodriguez-Cardona, of the University of New Hampshire, Durham, US, one of the study’s authors.

“This increase in fires leads to more input of inorganic solutes into local streams which can alter the chemistry and trigger issues like increased algal blooms and bacteria that can be harmful to humans who depend on these waterways for drinking water, fishing and their livelihoods.” When these waters reach the Arctic they can also dramatically alter the chemistry of the surrounding seas, says the study. – Climate News Network