Category Archives: Polar

2°C more heat may mean catastrophic sea level rise

The Paris Agreement to limit global heat could prevent catastrophic sea level rise, if states keep their promises to cut carbon.

LONDON, 7 May, 2021 − Climate scientists warn that − unless the world acts to limit global heating − the Antarctic ice sheet could begin irreversible collapse. The ice on the Antarctic continent could raise global sea levels by more than 47 metres, higher than a ten-storey building, and enough to unleash catastrophic sea level rise.

Global warming of just 3°C above the long-term average for most of human history would bring on a sea level rise from south polar melting of at least 0.5cms a year from about 2060 onwards.

Right now, greenhouse gas emissions continue to increase as nations burn ever more coal, oil and gas to power economic growth, and the world is on course for temperatures significantly above 3°C.

Researchers calculate in the journal Nature that any global warming that exceeds the target of no more than 2°C by 2100, agreed by almost all of the world’s nations in Paris in 2015, will put the ice shelves that ring the southern continent at risk of melting.

“Unstoppable, catastrophic sea level rise from Antarctica [may] be triggered if the Paris Agreement temperature targets are exceeded”

The mass and extent of sea ice acts as a buttress to flow from higher ground. If the sea ice melts, then the flow of glacial ice to the sea will accelerate.

“Ice-sheet collapse is irreversible over thousands of years, and if the Antarctic ice sheet collapse becomes unstable it could continue to retreat for centuries,” said Daniel Gilford of Rutgers University in the US, one of the research team. “That’s regardless of whether emissions mitigation strategies such as removing carbon dioxide from the atmosphere are employed.”

The finding is based on computer simulation backed up by detailed knowledge of at least some of the more prominent glaciers in West Antarctica, and of the response of the sea ice offshore to warmer winds and ocean currents.

Nor can it be a surprise to climate scientists: they have been warning for years of the potential loss of shelf-ice, they have already warned that ice loss could become irreversible, and they have measured the rates of loss often enough to be confident that this is accelerating.

On course for 3°C

The ice in Antarctica sits on a landmass bigger than the entire US and European Union combined: the burden of ice adds up to 30 million cubic kilometres, and some of it flows as vast glaciers 50kms wide and 2000 metres deep. And there has been concern for years that some flows are accelerating.

The Paris Agreement actually settled on the phrase “well below 2°C” as the global ambition for 2100. The national plans declared so far to reduce emissions commit the planet to a warming of 3°C or more.

The fear is that at 3°C nothing could prevent eventual ice sheet attrition over the following centuries. The latest research confirms that fear with a more than usually forthright scientific conclusion.

“These results demonstrate the possibility that unstoppable, catastrophic sea level rise from Antarctica will be triggered if the Paris Agreement temperature targets are exceeded,” the scientists write. − Climate News Network

The Paris Agreement to limit global heat could prevent catastrophic sea level rise, if states keep their promises to cut carbon.

LONDON, 7 May, 2021 − Climate scientists warn that − unless the world acts to limit global heating − the Antarctic ice sheet could begin irreversible collapse. The ice on the Antarctic continent could raise global sea levels by more than 47 metres, higher than a ten-storey building, and enough to unleash catastrophic sea level rise.

Global warming of just 3°C above the long-term average for most of human history would bring on a sea level rise from south polar melting of at least 0.5cms a year from about 2060 onwards.

Right now, greenhouse gas emissions continue to increase as nations burn ever more coal, oil and gas to power economic growth, and the world is on course for temperatures significantly above 3°C.

Researchers calculate in the journal Nature that any global warming that exceeds the target of no more than 2°C by 2100, agreed by almost all of the world’s nations in Paris in 2015, will put the ice shelves that ring the southern continent at risk of melting.

“Unstoppable, catastrophic sea level rise from Antarctica [may] be triggered if the Paris Agreement temperature targets are exceeded”

The mass and extent of sea ice acts as a buttress to flow from higher ground. If the sea ice melts, then the flow of glacial ice to the sea will accelerate.

“Ice-sheet collapse is irreversible over thousands of years, and if the Antarctic ice sheet collapse becomes unstable it could continue to retreat for centuries,” said Daniel Gilford of Rutgers University in the US, one of the research team. “That’s regardless of whether emissions mitigation strategies such as removing carbon dioxide from the atmosphere are employed.”

The finding is based on computer simulation backed up by detailed knowledge of at least some of the more prominent glaciers in West Antarctica, and of the response of the sea ice offshore to warmer winds and ocean currents.

Nor can it be a surprise to climate scientists: they have been warning for years of the potential loss of shelf-ice, they have already warned that ice loss could become irreversible, and they have measured the rates of loss often enough to be confident that this is accelerating.

On course for 3°C

The ice in Antarctica sits on a landmass bigger than the entire US and European Union combined: the burden of ice adds up to 30 million cubic kilometres, and some of it flows as vast glaciers 50kms wide and 2000 metres deep. And there has been concern for years that some flows are accelerating.

The Paris Agreement actually settled on the phrase “well below 2°C” as the global ambition for 2100. The national plans declared so far to reduce emissions commit the planet to a warming of 3°C or more.

The fear is that at 3°C nothing could prevent eventual ice sheet attrition over the following centuries. The latest research confirms that fear with a more than usually forthright scientific conclusion.

“These results demonstrate the possibility that unstoppable, catastrophic sea level rise from Antarctica will be triggered if the Paris Agreement temperature targets are exceeded,” the scientists write. − Climate News Network

Human activity alters Earth’s spin on its axis

The planet may not catch fire, but climate change really has altered the Earth’s spin on its axis as it rounds the sun.

LONDON, 29 April, 2021 − Human action has altered Earth’s spin on its axis. Climate change since 1990 has altered both the rate and the direction of the drift of the north and south poles.

Chinese researchers report in the journal Geophysical Research Letters that on the basis of their calculations, the dramatic melting of the Antarctic and Greenland ice caps and the Andean glaciers of South America has shifted the weight of the global water storage system and affected the planetary drift of the poles.

This glacial loss has been compounded by massive increases in the use of groundwater − most of the planet’s fresh water is in fact stored in subterranean aquifers − which have helped to accelerate the rate of change.

It sounds like the plot of a science fiction film. It was in fact the plot of a British 1961 science fiction film, The Day the Earth Caught Fire. In that fantasia, Cold War superpower nuclear tests unintentionally alter the planet’s axis of rotation and trigger dramatic changes in climate.

In fact, in the real-life, here-and-now version of planetary rotational shift, climate change driven by economic growth powered by profligate fossil fuel use is the cause. And the superpowers have yet to decide upon a course correction.

Polar speed-up

There is a second difference: the axis of the rotational poles has always shifted, from year to year, in response to the distribution of ice and groundwater, and the oceanic currents; and from aeon to aeon in response to the movements of the continents, and the sloshing of molten iron at the Earth’s core.

What has happened since 1990 is that water loss from both the glaciated land surface and the soil beneath the inhabited surface has been so pronounced that it has tilted the North Pole away from Canada and towards Russia, and accelerated the rate at which this is happening.

Since 1990, geographic North has been tilting, in geodetic language, towards longitude 26°E at the rate of 3.28 milliseconds of arc per year. One millisecond of arc is about 3 cms.

The story has been pieced together by data from a US-German satellite system known as GRACE (short for Gravity Recovery and Climate Experiment), which has been recording ice loss and water storage for most of this century.

“The faster ice-melting under global warming was the most likely cause of the directional change of the polar drift in the 1990s”

The researchers, from the Chinese Academy of Sciences, already had access to 176 years of precision measurement of the polar axial shift. In fact, the loss of ice from both the north and south polar regions has been colossal, and has been happening at speed.

Groundwater, too, has been abstracted at accelerating rates and the study notes that while in 1989 India pumped 194 billion cubic metres from the soil, by 2010 this had reached 351 billion cubic metres. There had, too, been dramatic changes in the water levels of vast inland lakes such as the Aral Sea.

The planet is always in a state of change: the magnetic poles are on the move and scientists have confirmed that climate over very long periods is affected by changes in planetary orbit.

Other teams of researchers had separately confirmed that climate change − and the redistribution of water around the planet − must have altered the length of the day by millionths of a second in the course of a year. But the new research has established something more immediately measurable: the alteration of the pattern of rotational tilt.

“The faster ice-melting under global warming was the most likely cause of the directional change of the polar drift in the 1990s,” the researchers conclude. − Climate News Network

The planet may not catch fire, but climate change really has altered the Earth’s spin on its axis as it rounds the sun.

LONDON, 29 April, 2021 − Human action has altered Earth’s spin on its axis. Climate change since 1990 has altered both the rate and the direction of the drift of the north and south poles.

Chinese researchers report in the journal Geophysical Research Letters that on the basis of their calculations, the dramatic melting of the Antarctic and Greenland ice caps and the Andean glaciers of South America has shifted the weight of the global water storage system and affected the planetary drift of the poles.

This glacial loss has been compounded by massive increases in the use of groundwater − most of the planet’s fresh water is in fact stored in subterranean aquifers − which have helped to accelerate the rate of change.

It sounds like the plot of a science fiction film. It was in fact the plot of a British 1961 science fiction film, The Day the Earth Caught Fire. In that fantasia, Cold War superpower nuclear tests unintentionally alter the planet’s axis of rotation and trigger dramatic changes in climate.

In fact, in the real-life, here-and-now version of planetary rotational shift, climate change driven by economic growth powered by profligate fossil fuel use is the cause. And the superpowers have yet to decide upon a course correction.

Polar speed-up

There is a second difference: the axis of the rotational poles has always shifted, from year to year, in response to the distribution of ice and groundwater, and the oceanic currents; and from aeon to aeon in response to the movements of the continents, and the sloshing of molten iron at the Earth’s core.

What has happened since 1990 is that water loss from both the glaciated land surface and the soil beneath the inhabited surface has been so pronounced that it has tilted the North Pole away from Canada and towards Russia, and accelerated the rate at which this is happening.

Since 1990, geographic North has been tilting, in geodetic language, towards longitude 26°E at the rate of 3.28 milliseconds of arc per year. One millisecond of arc is about 3 cms.

The story has been pieced together by data from a US-German satellite system known as GRACE (short for Gravity Recovery and Climate Experiment), which has been recording ice loss and water storage for most of this century.

“The faster ice-melting under global warming was the most likely cause of the directional change of the polar drift in the 1990s”

The researchers, from the Chinese Academy of Sciences, already had access to 176 years of precision measurement of the polar axial shift. In fact, the loss of ice from both the north and south polar regions has been colossal, and has been happening at speed.

Groundwater, too, has been abstracted at accelerating rates and the study notes that while in 1989 India pumped 194 billion cubic metres from the soil, by 2010 this had reached 351 billion cubic metres. There had, too, been dramatic changes in the water levels of vast inland lakes such as the Aral Sea.

The planet is always in a state of change: the magnetic poles are on the move and scientists have confirmed that climate over very long periods is affected by changes in planetary orbit.

Other teams of researchers had separately confirmed that climate change − and the redistribution of water around the planet − must have altered the length of the day by millionths of a second in the course of a year. But the new research has established something more immediately measurable: the alteration of the pattern of rotational tilt.

“The faster ice-melting under global warming was the most likely cause of the directional change of the polar drift in the 1990s,” the researchers conclude. − Climate News Network

Loss of Arctic sea ice can spoil French wine harvest

What happens in the Arctic may not stay there. Loss of Arctic sea ice can dump the polar blizzards elsewhere.

LONDON, 19 April, 2021 − Once again, scientists have linked a weather-related catastrophe directly to human-induced climate change. Extreme frost and springtime snowfalls in Western Europe can be pinned to the dramatic loss of Arctic sea ice.

So, paradoxically, global heating may have had the unexpected effect of wiping out around one third of the French wine harvest for this coming year, after temperatures so low that growers were forced to light bonfires in their vineyards to save the first buds from the chill.

“Climate change doesn’t always manifest in the most obvious ways,” said Alun Hubbard, of the Arctic University of Norway. “It’s easy to extrapolate models to show that winters are getting warmer and to forecast a virtually snow-free future in Europe, but our most recent study shows that is too simplistic. We should be beware of making broad, sweeping statements about the impacts of climate change.”

Professor Hubbard and colleagues report in the journal Nature Geoscience that they measured telltale isotope signatures in water vapour from Finland in February 2018 during an episode of freezing snow in Europe, in an anticyclone dubbed “the Beast from the East” by meteorologists and the media.

“The abrupt changes being witnessed across the Arctic now really are affecting the entire planet”

They found that the Barents Sea north of Scandinavia was anomalously warm. And 60% of the sea’s surface was free of ice, and the same sea lost 140 billion tonnes of water to evaporation during this too-warm February. This enormous atmospheric burden of water vapour provided, they calculate, 88% of the snow that was to fall over northern Europe that month.

Then they looked at the pattern over the years from 1979 to 2020, to find that, for every square metre of ice that vanished in the month of March − itself part of a pattern of Arctic temperature rise − evaporation across the Barents Sea increased by 70 kg, and this could be matched with increases in Europe’s maximum snowfall.

“Our analysis directly links Arctic sea ice loss with increased evaporation and extreme snow fall,” they write, and warn that by 2080 an ice-free Barents Sea “will be a major source of winter moisture for continental Europe.”

The Beast from the East brought much of Europe to a halt, at an economic cost of an estimated $1bn (£0.72bn) a day. It is still rare for researchers to directly link any particular weather event with climate change driven by profligate use of fossil fuels − that is because climate is what forecasters can reasonably expect, but weather is what actually happens − but some scientists have begun to do so with increasing confidence. And this time, they can explain why.

Natural complexity

The ice cover over the Barents Sea has fallen by 54% since 1979, at the rate of 11,200 sq kms a year, and snow mass across Eurasia has increased. The latest study confirms the link: the isotope signature of Barents water was repeated in the European snows that arrived with the Beast from the East.

“What we’re finding is that sea ice is effectively a lid on the ocean. And with its long term reduction across the Arctic, we’re seeing increasing amounts of moisture enter the atmosphere during winter, which directly impacts our weather further south, causing extremely heavy snowfalls,” said Hannah Bailey of the University of Oulu in Finland, who led the research.

“It might seem counter-intuitive, but nature is complex and what happens in the Arctic doesn’t stay in the Arctic.”

And Professor Hubbard said: “This study illustrates that the abrupt changes being witnessed across the Arctic now really are affecting the entire planet.” − Climate News Network

What happens in the Arctic may not stay there. Loss of Arctic sea ice can dump the polar blizzards elsewhere.

LONDON, 19 April, 2021 − Once again, scientists have linked a weather-related catastrophe directly to human-induced climate change. Extreme frost and springtime snowfalls in Western Europe can be pinned to the dramatic loss of Arctic sea ice.

So, paradoxically, global heating may have had the unexpected effect of wiping out around one third of the French wine harvest for this coming year, after temperatures so low that growers were forced to light bonfires in their vineyards to save the first buds from the chill.

“Climate change doesn’t always manifest in the most obvious ways,” said Alun Hubbard, of the Arctic University of Norway. “It’s easy to extrapolate models to show that winters are getting warmer and to forecast a virtually snow-free future in Europe, but our most recent study shows that is too simplistic. We should be beware of making broad, sweeping statements about the impacts of climate change.”

Professor Hubbard and colleagues report in the journal Nature Geoscience that they measured telltale isotope signatures in water vapour from Finland in February 2018 during an episode of freezing snow in Europe, in an anticyclone dubbed “the Beast from the East” by meteorologists and the media.

“The abrupt changes being witnessed across the Arctic now really are affecting the entire planet”

They found that the Barents Sea north of Scandinavia was anomalously warm. And 60% of the sea’s surface was free of ice, and the same sea lost 140 billion tonnes of water to evaporation during this too-warm February. This enormous atmospheric burden of water vapour provided, they calculate, 88% of the snow that was to fall over northern Europe that month.

Then they looked at the pattern over the years from 1979 to 2020, to find that, for every square metre of ice that vanished in the month of March − itself part of a pattern of Arctic temperature rise − evaporation across the Barents Sea increased by 70 kg, and this could be matched with increases in Europe’s maximum snowfall.

“Our analysis directly links Arctic sea ice loss with increased evaporation and extreme snow fall,” they write, and warn that by 2080 an ice-free Barents Sea “will be a major source of winter moisture for continental Europe.”

The Beast from the East brought much of Europe to a halt, at an economic cost of an estimated $1bn (£0.72bn) a day. It is still rare for researchers to directly link any particular weather event with climate change driven by profligate use of fossil fuels − that is because climate is what forecasters can reasonably expect, but weather is what actually happens − but some scientists have begun to do so with increasing confidence. And this time, they can explain why.

Natural complexity

The ice cover over the Barents Sea has fallen by 54% since 1979, at the rate of 11,200 sq kms a year, and snow mass across Eurasia has increased. The latest study confirms the link: the isotope signature of Barents water was repeated in the European snows that arrived with the Beast from the East.

“What we’re finding is that sea ice is effectively a lid on the ocean. And with its long term reduction across the Arctic, we’re seeing increasing amounts of moisture enter the atmosphere during winter, which directly impacts our weather further south, causing extremely heavy snowfalls,” said Hannah Bailey of the University of Oulu in Finland, who led the research.

“It might seem counter-intuitive, but nature is complex and what happens in the Arctic doesn’t stay in the Arctic.”

And Professor Hubbard said: “This study illustrates that the abrupt changes being witnessed across the Arctic now really are affecting the entire planet.” − Climate News Network

Climate heating may speed up to unexpected levels

When the ice thaws, ocean levels rise. And four new studies show climate heating can happen fast.

LONDON, 15 April, 2021 − If climate heating continues apace and the planet goes on warming, then up to a third of Antarctica’s ice shelf could tip into the sea.

And tip is the operative word, according to a separate study: at least one Antarctic glacier could be about to tip into rapid and irreversible retreat if temperatures go on rising.

And rise they could: evidence from the past in a third research programme confirms that at the end of the last Ice Age, Greenland’s temperature rose by somewhere between 5°C and 16°C in just decades, in line with a cascade of climate change events.

And ominously a fourth study of climate change 14,600 years ago confirmed that as the ice retreated, sea levels rose at 10 times the current rate, to 3.6 metres in just a century, and up to 18 metres in a 500-year sequence.

Each study is, on its own, an examination of the complexities of the planetary climate machine and the role of the polar ice sheets in climate change. But the message of the four together is a stark one: climate change is happening, could accelerate and could happen at unexpected speeds.

Unstable at 4°C

The Antarctic ice sheet floats on the sea: were it all to melt, sea levels globally would remain much the same. But the ice sheet plays an important role in stabilising the massive reserves of ice on the continental surface.

“Ice shelves are important buffers preventing glaciers on land from flowing freely into the ocean and contributing to sea level rise,” warned Ella Gilbert, a meteorologist at the University of Reading in the UK. “When they collapse, it’s like a giant cork being removed from a bottle, allowing unimaginable amounts of water from glaciers to pour into the sea.”

She and colleagues report in the journal Geophysical Research Letters that their detailed study of the vulnerable platforms of floating ice around the continent revealed that half a million square kilometres of shelf − 34% in total, including two-thirds of all the ice off the Antarctic Peninsula − would become unstable if global temperatures rose by 4°C, under the business-as-usual scenario in which nations went on burning ever-greater quantities of fossil fuel.

If however the world kept to the limit it agreed in Paris in 2015, that would halve the area at risk and perhaps avoid significant sea level rise. But already, just two Antarctic glaciers are responsible for around 10% of sea level rise at the current rate, and researchers have been warning for years that the Pine Island and Thwaites glaciers in West Antarctica could be at risk.

Now researchers in the UK report in the journal The Cryosphere that their computer simulation had identified a series of tipping points for the Pine Island flow.

“Ice shelves are important buffers preventing glaciers on land from contributing to sea level rise. When they collapse, it’s like a giant cork being removed from a bottle, allowing unimaginable amounts of water to pour into the sea”

The third of these, triggered by ocean temperatures that had warmed just 1.2°C, would lead to irretrievable retreat of the entire glacier. Hilmar Gudmundsson, a glaciologist at the UK’s Northumbria University and one of the authors, called the research a “major step forward” in the understanding of the dynamics of the region.

“But the findings of this study also concern me”, he said. “Should the glacier enter unstable irreversible retreat, the impact on sea level could be measured in metres, and as this study shows, once the retreat starts it might be impossible to halt it.”

Rapid polar melt is part of the pattern of climate history. Danish researchers report in Nature Communications that, on the evidence preserved in Greenland ice cores, they identified a series of 30 abrupt climate changes at the close of the Last Ice Age, affecting North Atlantic ocean currents, wind and rainfall patterns and the spread of sea ice: a set of physical processes that changed together, like a row of cascading dominoes.

The precise order of events was difficult to ascertain, but during that sequence the temperature of Greenland soared by 5°C to 16°C in decades to centuries. The question remains open: could such things happen today?

“The results emphasise the importance of trying to limit climate change by, for example, cutting anthropogenic emissions of CO2 and other greenhouse gases, both to reduce the predictable, gradual climate change and to reduce the risk of future abrupt climate change,” said Sune Olander Rasmussen, at the Niels Bohr Institute in Copenhagen, one of the authors.

Greenland’s future role

“If you do not want the dominoes to topple over, you are better off not to push the table they stand on too much.”

And another study in the same journal by British scientists reports on a close study of geological evidence to decipher the pattern of events during the largest and most rapid pulse of sea level rise at the close of the last Ice Age.

Their study suggested that although the sea levels rose 18 metres in about 500 years − a rate of about 3.6 metres a century − it all happened with relatively little help from a melting Antarctica. As the great glaciers retreated from North America, Europe and Asia, so the oceans rose.

“The next big question is to work out what triggered the ice melt, and what impact the massive influx of meltwater had on ocean currents in the North Atlantic,” said Pippa Whitehouse of the University of Durham, one of the researchers.

“This is very much on our minds today − any disruption to the Gulf Stream, for example due to melting of the Greenland Ice Sheet, will have significant consequences for the UK climate.” − Climate News Network

When the ice thaws, ocean levels rise. And four new studies show climate heating can happen fast.

LONDON, 15 April, 2021 − If climate heating continues apace and the planet goes on warming, then up to a third of Antarctica’s ice shelf could tip into the sea.

And tip is the operative word, according to a separate study: at least one Antarctic glacier could be about to tip into rapid and irreversible retreat if temperatures go on rising.

And rise they could: evidence from the past in a third research programme confirms that at the end of the last Ice Age, Greenland’s temperature rose by somewhere between 5°C and 16°C in just decades, in line with a cascade of climate change events.

And ominously a fourth study of climate change 14,600 years ago confirmed that as the ice retreated, sea levels rose at 10 times the current rate, to 3.6 metres in just a century, and up to 18 metres in a 500-year sequence.

Each study is, on its own, an examination of the complexities of the planetary climate machine and the role of the polar ice sheets in climate change. But the message of the four together is a stark one: climate change is happening, could accelerate and could happen at unexpected speeds.

Unstable at 4°C

The Antarctic ice sheet floats on the sea: were it all to melt, sea levels globally would remain much the same. But the ice sheet plays an important role in stabilising the massive reserves of ice on the continental surface.

“Ice shelves are important buffers preventing glaciers on land from flowing freely into the ocean and contributing to sea level rise,” warned Ella Gilbert, a meteorologist at the University of Reading in the UK. “When they collapse, it’s like a giant cork being removed from a bottle, allowing unimaginable amounts of water from glaciers to pour into the sea.”

She and colleagues report in the journal Geophysical Research Letters that their detailed study of the vulnerable platforms of floating ice around the continent revealed that half a million square kilometres of shelf − 34% in total, including two-thirds of all the ice off the Antarctic Peninsula − would become unstable if global temperatures rose by 4°C, under the business-as-usual scenario in which nations went on burning ever-greater quantities of fossil fuel.

If however the world kept to the limit it agreed in Paris in 2015, that would halve the area at risk and perhaps avoid significant sea level rise. But already, just two Antarctic glaciers are responsible for around 10% of sea level rise at the current rate, and researchers have been warning for years that the Pine Island and Thwaites glaciers in West Antarctica could be at risk.

Now researchers in the UK report in the journal The Cryosphere that their computer simulation had identified a series of tipping points for the Pine Island flow.

“Ice shelves are important buffers preventing glaciers on land from contributing to sea level rise. When they collapse, it’s like a giant cork being removed from a bottle, allowing unimaginable amounts of water to pour into the sea”

The third of these, triggered by ocean temperatures that had warmed just 1.2°C, would lead to irretrievable retreat of the entire glacier. Hilmar Gudmundsson, a glaciologist at the UK’s Northumbria University and one of the authors, called the research a “major step forward” in the understanding of the dynamics of the region.

“But the findings of this study also concern me”, he said. “Should the glacier enter unstable irreversible retreat, the impact on sea level could be measured in metres, and as this study shows, once the retreat starts it might be impossible to halt it.”

Rapid polar melt is part of the pattern of climate history. Danish researchers report in Nature Communications that, on the evidence preserved in Greenland ice cores, they identified a series of 30 abrupt climate changes at the close of the Last Ice Age, affecting North Atlantic ocean currents, wind and rainfall patterns and the spread of sea ice: a set of physical processes that changed together, like a row of cascading dominoes.

The precise order of events was difficult to ascertain, but during that sequence the temperature of Greenland soared by 5°C to 16°C in decades to centuries. The question remains open: could such things happen today?

“The results emphasise the importance of trying to limit climate change by, for example, cutting anthropogenic emissions of CO2 and other greenhouse gases, both to reduce the predictable, gradual climate change and to reduce the risk of future abrupt climate change,” said Sune Olander Rasmussen, at the Niels Bohr Institute in Copenhagen, one of the authors.

Greenland’s future role

“If you do not want the dominoes to topple over, you are better off not to push the table they stand on too much.”

And another study in the same journal by British scientists reports on a close study of geological evidence to decipher the pattern of events during the largest and most rapid pulse of sea level rise at the close of the last Ice Age.

Their study suggested that although the sea levels rose 18 metres in about 500 years − a rate of about 3.6 metres a century − it all happened with relatively little help from a melting Antarctica. As the great glaciers retreated from North America, Europe and Asia, so the oceans rose.

“The next big question is to work out what triggered the ice melt, and what impact the massive influx of meltwater had on ocean currents in the North Atlantic,” said Pippa Whitehouse of the University of Durham, one of the researchers.

“This is very much on our minds today − any disruption to the Gulf Stream, for example due to melting of the Greenland Ice Sheet, will have significant consequences for the UK climate.” − Climate News Network

Antarctic warming speed-up alarms researchers

The world’s largest reservoir of snow and ice could be melting faster than ever. Two new studies highlight Antarctic warming.

LONDON, 4 March, 2021 − Antarctic warming is accelerating: at least one of the southern continent’s ice shelves has been melting faster than ever. The polar summer of 2019-20 set a new record for temperatures above freezing point over the George VI ice shelf off the Antarctic Peninsula.

The finding is ominous: the ice shelves form a natural buttress that slows the rate of glacier flow from the continental bedrock. The faster the glaciers flow into the sea, the higher the hazard of sea level rise.

And a second study confirms that this is already happening in West Antarctica: researchers looked at 25 years of satellite observation of 14 glaciers in the Getz sector to find that meltwater is flowing into the Amundsen Sea ever faster. Between 1994 and 2018, these glaciers lost 315 billion tonnes of ice, enough to raise global sea levels by almost 1mm.

Melting rates in Antarctica have been a source of alarm for years. The latest studies confirm the picture of continuing melt.

“The high rates of increased glacier speed − coupled with ice thinning − confirm the Getz basin is losing more ice than it gains through snowfall”

US scientists report in the journal The Cryosphere that they too used satellite observation − 41 years of it − to measure summer meltwater on the ice and in the near-surface snow of the northern part of the George VI ice shelf. They identified the most widespread melt and the greatest total of melt days of any season during the 2019-2020 summer.

Air temperatures were above freezing for up to 90 hours, allowing pools of meltwater to collect on the shelf. At its peak 23% of the region was covered with water: the equivalent, in glaciology’s favourite popular measure, of 250,000 Olympic swimming pools.

“When the temperature is above zero degrees Celsius, that limits refreezing and also leads to further melting,” said Alison Banwell, of the University of Colorado at Boulder, who led the study. “Water absorbs more radiation than snow and ice, and that leads to even more melting.”

Remote and untrodden

The Getz shelf is one of the biggest of a sector of the West Antarctic known as Marie Byrd Land. A new report in Nature Communications confirms that all 14 measured glaciers there have picked up speed and reach the ocean ever more swiftly.

Three of them have accelerated by more than 44%. And over the years the loss of ice has been the equivalent of 126 million Olympic swimming pools − all of it now adding to global sea level rise.

“The Getz region of Antarctica is so remote that humans have never set foot on most of this part of the continent,” said Heather Selley, of the University of Leeds, UK, first author. “Satellite radar altimetry records have shown substantial thinning of the ice sheet.

“However, the high rates of increased glacier speed − coupled with ice thinning − now confirm the Getz basin is in dynamic imbalance, meaning that it is losing more ice than it gains through snowfall.” − Climate News Network

The world’s largest reservoir of snow and ice could be melting faster than ever. Two new studies highlight Antarctic warming.

LONDON, 4 March, 2021 − Antarctic warming is accelerating: at least one of the southern continent’s ice shelves has been melting faster than ever. The polar summer of 2019-20 set a new record for temperatures above freezing point over the George VI ice shelf off the Antarctic Peninsula.

The finding is ominous: the ice shelves form a natural buttress that slows the rate of glacier flow from the continental bedrock. The faster the glaciers flow into the sea, the higher the hazard of sea level rise.

And a second study confirms that this is already happening in West Antarctica: researchers looked at 25 years of satellite observation of 14 glaciers in the Getz sector to find that meltwater is flowing into the Amundsen Sea ever faster. Between 1994 and 2018, these glaciers lost 315 billion tonnes of ice, enough to raise global sea levels by almost 1mm.

Melting rates in Antarctica have been a source of alarm for years. The latest studies confirm the picture of continuing melt.

“The high rates of increased glacier speed − coupled with ice thinning − confirm the Getz basin is losing more ice than it gains through snowfall”

US scientists report in the journal The Cryosphere that they too used satellite observation − 41 years of it − to measure summer meltwater on the ice and in the near-surface snow of the northern part of the George VI ice shelf. They identified the most widespread melt and the greatest total of melt days of any season during the 2019-2020 summer.

Air temperatures were above freezing for up to 90 hours, allowing pools of meltwater to collect on the shelf. At its peak 23% of the region was covered with water: the equivalent, in glaciology’s favourite popular measure, of 250,000 Olympic swimming pools.

“When the temperature is above zero degrees Celsius, that limits refreezing and also leads to further melting,” said Alison Banwell, of the University of Colorado at Boulder, who led the study. “Water absorbs more radiation than snow and ice, and that leads to even more melting.”

Remote and untrodden

The Getz shelf is one of the biggest of a sector of the West Antarctic known as Marie Byrd Land. A new report in Nature Communications confirms that all 14 measured glaciers there have picked up speed and reach the ocean ever more swiftly.

Three of them have accelerated by more than 44%. And over the years the loss of ice has been the equivalent of 126 million Olympic swimming pools − all of it now adding to global sea level rise.

“The Getz region of Antarctica is so remote that humans have never set foot on most of this part of the continent,” said Heather Selley, of the University of Leeds, UK, first author. “Satellite radar altimetry records have shown substantial thinning of the ice sheet.

“However, the high rates of increased glacier speed − coupled with ice thinning − now confirm the Getz basin is in dynamic imbalance, meaning that it is losing more ice than it gains through snowfall.” − Climate News Network

Scientists say world’s huge ice loss is speeding up

The frozen world is shrinking at a “staggering” rate. New research takes a measure of the world’s huge ice loss.

LONDON, 27 January, 2021 − Planet Earth is losing its frozen mantle faster than ever as the world’s huge ice loss intensifies. Between 1994 and 2017, the polar regions and the mountain glaciers said farewell to a total of 28 million million tonnes of ice. This is a quantity large enough to conceal the entire United Kingdom under an ice sheet 100 metres thick.

More alarmingly, scientists warn, the rate of loss has been accelerating. Over the course of the 23-year survey of the planet’s ice budget, there has been a 65% increase in the flow of meltwater from the glaciers, ice shelves and ice sheets.

Early in the last decade of the last century, ice loss was counted at 0.8 trillion tonnes a year. By 2017, this had increased to 1.3 trillion tonnes a year, says a new study in the journal The Cryosphere.

The finding should come as no great surprise. Thanks to profligate combustion of fossil fuels and the clearance of forests and grasslands, the planet is warming: 2020 has been awarded the unwelcome title of equal place as warmest year ever recorded, and the last six years have been the six warmest since records began.

“The vast majority of Earth’s ice loss is a direct consequence of climate warming.”

Researchers warned last year that the melting rate of Greenland’s ice sheet − the biggest in the northern hemisphere − would soon hit a 12,000 year high. A second group warned in the same month that ice loss from Antarctica would soon become irreversible.

The latest research, based on satellite data, confirms all fears. “Although every region we studied lost ice, losses from the Antarctic and Greenland ice sheets have accelerated the most,” said Thomas Slater, of the University of Leeds in the UK, who led the research.

“The ice sheets are now following the worst case climate warning scenarios set out by the Intergovernmental Panel on Climate Change. Sea level rise on this scale will have very serious impacts on coastal communities this century.”

The scientists measured loss from the land-based ice sheets of Greenland and Antarctica, from the shelf ice around Antarctica and from the drifting sea ice in the Arctic and Southern Oceans, as well as the retreat of 215,000 mountain glaciers worldwide.

‘Staggering’ loss

During the 23-year-survey, thanks to rising air and ocean temperatures, the Arctic Ocean lost 7.6 trillion tonnes, the Antarctic ice shelves 6.5 trillion tonnes. Melting sea ice will not affect sea levels, but it will expose greater areas of ocean to radiation, which would otherwise be reflected back into space. So the loss of sea ice can only lead to even more warming.

The researchers claim theirs is the first full global survey, but they also concede it can only be incomplete: they did not take the measure of fallen snow on land, nor of the icy soils of the permafrost, and they did not try to measure the loss of winter ice on lakes and rivers − but they note that the duration of ice on lakes has fallen by 12 days in the last two centuries, thanks to atmospheric warming.

However, they could put a measure on ice losses from land − 6.1 trillion tonnes from mountain glaciers worldwide, 3.8 trillion tonnes from the Greenland ice sheet, 2.5 trillion tonnes from the Antarctic surface − enough to raise global sea levels by 35mm.

Scientific studies tend to be presented without emotive language. But the researchers call their total of lost ice “staggering”. And they warn: “There can be little doubt that the vast majority of Earth’s ice loss is a direct consequence of climate warming.” − Climate News Network

The frozen world is shrinking at a “staggering” rate. New research takes a measure of the world’s huge ice loss.

LONDON, 27 January, 2021 − Planet Earth is losing its frozen mantle faster than ever as the world’s huge ice loss intensifies. Between 1994 and 2017, the polar regions and the mountain glaciers said farewell to a total of 28 million million tonnes of ice. This is a quantity large enough to conceal the entire United Kingdom under an ice sheet 100 metres thick.

More alarmingly, scientists warn, the rate of loss has been accelerating. Over the course of the 23-year survey of the planet’s ice budget, there has been a 65% increase in the flow of meltwater from the glaciers, ice shelves and ice sheets.

Early in the last decade of the last century, ice loss was counted at 0.8 trillion tonnes a year. By 2017, this had increased to 1.3 trillion tonnes a year, says a new study in the journal The Cryosphere.

The finding should come as no great surprise. Thanks to profligate combustion of fossil fuels and the clearance of forests and grasslands, the planet is warming: 2020 has been awarded the unwelcome title of equal place as warmest year ever recorded, and the last six years have been the six warmest since records began.

“The vast majority of Earth’s ice loss is a direct consequence of climate warming.”

Researchers warned last year that the melting rate of Greenland’s ice sheet − the biggest in the northern hemisphere − would soon hit a 12,000 year high. A second group warned in the same month that ice loss from Antarctica would soon become irreversible.

The latest research, based on satellite data, confirms all fears. “Although every region we studied lost ice, losses from the Antarctic and Greenland ice sheets have accelerated the most,” said Thomas Slater, of the University of Leeds in the UK, who led the research.

“The ice sheets are now following the worst case climate warning scenarios set out by the Intergovernmental Panel on Climate Change. Sea level rise on this scale will have very serious impacts on coastal communities this century.”

The scientists measured loss from the land-based ice sheets of Greenland and Antarctica, from the shelf ice around Antarctica and from the drifting sea ice in the Arctic and Southern Oceans, as well as the retreat of 215,000 mountain glaciers worldwide.

‘Staggering’ loss

During the 23-year-survey, thanks to rising air and ocean temperatures, the Arctic Ocean lost 7.6 trillion tonnes, the Antarctic ice shelves 6.5 trillion tonnes. Melting sea ice will not affect sea levels, but it will expose greater areas of ocean to radiation, which would otherwise be reflected back into space. So the loss of sea ice can only lead to even more warming.

The researchers claim theirs is the first full global survey, but they also concede it can only be incomplete: they did not take the measure of fallen snow on land, nor of the icy soils of the permafrost, and they did not try to measure the loss of winter ice on lakes and rivers − but they note that the duration of ice on lakes has fallen by 12 days in the last two centuries, thanks to atmospheric warming.

However, they could put a measure on ice losses from land − 6.1 trillion tonnes from mountain glaciers worldwide, 3.8 trillion tonnes from the Greenland ice sheet, 2.5 trillion tonnes from the Antarctic surface − enough to raise global sea levels by 35mm.

Scientific studies tend to be presented without emotive language. But the researchers call their total of lost ice “staggering”. And they warn: “There can be little doubt that the vast majority of Earth’s ice loss is a direct consequence of climate warming.” − Climate News Network

Polar link unites far extremes of north and south

They are different worlds, one an ocean, the other a continent. But a polar link keeps them in touch with each other.

LONDON, 30 November, 2020 − The Arctic and Antarctica are literally a world apart, but for an unlikely polar link. Change in the mass of ice in the north can and does precipitate change in the furthest reaches of the southern hemisphere.

According to 40,000 years of geological evidence, when the Arctic Ocean ice retreats, global sea levels rise to start washing away the sea ice around the shelf of the vast frozen continent at the other extreme of the planet.

This pattern of action at a distance is confirmed by computer simulations: the planet’s two hemispheres are in a kind of conversation, according to a new study in the journal Nature.

“Our results highlight how interconnected the Earth system is, with changes in one part of the planet driving changes in another,” said Natalya Gomez, of McGill University in Canada, who led the study.

“In the modern era, we haven’t seen the kind of large ice sheet retreat that we might see in our future warming world. Looking to records and models of change in Earth’s history can inform us about this.”

“Ice sheets can influence each other over great distances. It’s as though they were talking to one another about sea level changes”

The Arctic is one of the fastest-warming places on the planet: what happens in the far north has reverberations throughout the hemisphere. And Antarctica, too, is changing swiftly.

Although both extremes of cold are vulnerable to global heating driven by profligate fossil fuel use and global-scale loss of forests, climate scientists have tended to consider them as separate cases.

But a closer look at geological records − ice cores and samples from the ocean bottom that offer evidence of iceberg drift across the millennia − revealed a connection. The polar link is real.

At the height of the last ice age more than 20,000 years ago, the mass of ice in the north lowered global sea levels and the Antarctic ice shelf advanced. As the world began to warm again, ice in the north began to flow into the sea. Sea levels rose in the southern hemisphere and this began to force a retreat of the Antarctic ice.

“Ice sheets can influence each other over great distances due to the water that flows between them. It’s as though they were talking to one another about sea level changes,” Dr Gomez said.

Dynamic ice

“Polar ice sheets are not just large static mounds of ice. They evolve on various different time scales and are in constant flux, with ice growing and retreating, depending on the climate and the surrounding water levels.

“They gain ice as snow piles up on top of them, then spread outwards under their own weight, and stream out into the surrounding ocean where their edges break off into icebergs.”

The evidence showed that sea level change in Antarctica and ice mass loss in the Arctic were linked, over a sequence of at least 40,000 years.

“These ice sheets are really dynamic, exciting and intriguing parts of the Earth’s climate system. It’s staggering to think of ice that is several kilometres thick, that covers an entire continent, and that is evolving on all of these different timescales with global consequences,” Dr Gomez said.

“It’s just motivation for trying to better understand these really massive systems that are so far away from us.” − Climate News Network

They are different worlds, one an ocean, the other a continent. But a polar link keeps them in touch with each other.

LONDON, 30 November, 2020 − The Arctic and Antarctica are literally a world apart, but for an unlikely polar link. Change in the mass of ice in the north can and does precipitate change in the furthest reaches of the southern hemisphere.

According to 40,000 years of geological evidence, when the Arctic Ocean ice retreats, global sea levels rise to start washing away the sea ice around the shelf of the vast frozen continent at the other extreme of the planet.

This pattern of action at a distance is confirmed by computer simulations: the planet’s two hemispheres are in a kind of conversation, according to a new study in the journal Nature.

“Our results highlight how interconnected the Earth system is, with changes in one part of the planet driving changes in another,” said Natalya Gomez, of McGill University in Canada, who led the study.

“In the modern era, we haven’t seen the kind of large ice sheet retreat that we might see in our future warming world. Looking to records and models of change in Earth’s history can inform us about this.”

“Ice sheets can influence each other over great distances. It’s as though they were talking to one another about sea level changes”

The Arctic is one of the fastest-warming places on the planet: what happens in the far north has reverberations throughout the hemisphere. And Antarctica, too, is changing swiftly.

Although both extremes of cold are vulnerable to global heating driven by profligate fossil fuel use and global-scale loss of forests, climate scientists have tended to consider them as separate cases.

But a closer look at geological records − ice cores and samples from the ocean bottom that offer evidence of iceberg drift across the millennia − revealed a connection. The polar link is real.

At the height of the last ice age more than 20,000 years ago, the mass of ice in the north lowered global sea levels and the Antarctic ice shelf advanced. As the world began to warm again, ice in the north began to flow into the sea. Sea levels rose in the southern hemisphere and this began to force a retreat of the Antarctic ice.

“Ice sheets can influence each other over great distances due to the water that flows between them. It’s as though they were talking to one another about sea level changes,” Dr Gomez said.

Dynamic ice

“Polar ice sheets are not just large static mounds of ice. They evolve on various different time scales and are in constant flux, with ice growing and retreating, depending on the climate and the surrounding water levels.

“They gain ice as snow piles up on top of them, then spread outwards under their own weight, and stream out into the surrounding ocean where their edges break off into icebergs.”

The evidence showed that sea level change in Antarctica and ice mass loss in the Arctic were linked, over a sequence of at least 40,000 years.

“These ice sheets are really dynamic, exciting and intriguing parts of the Earth’s climate system. It’s staggering to think of ice that is several kilometres thick, that covers an entire continent, and that is evolving on all of these different timescales with global consequences,” Dr Gomez said.

“It’s just motivation for trying to better understand these really massive systems that are so far away from us.” − Climate News Network

Antarctic depths warm far beyond oceanic average

Heat from factories and car exhausts must go somewhere. A surprising amount is now sunk in the remote Antarctic depths.

LONDON, 28 October, 2020 − Thanks to global heating, a vital part of the Southern Ocean is warming at a rate five times faster than the average for the Blue Planet as a whole, in the far Antarctic depths: 2000 metres or more below the surface of the Weddell Sea.

It is happening because at that depth the Weddell Sea has absorbed five times as much atmospheric heat − fuelled by greenhouse gas emissions from human fossil fuel combustion − as the average for the rest of the ocean. But what happens out of sight and far below the surface may not stay invisible. The Weddell Sea is where vast volumes of water circulate.

The fear is that such dramatic warming at depth could end up weakening a powerful current that encircles Antarctica, according to a new study in the Journal of Climate.

The evidence comes from 30 years of temperature and salinity samples, taken at the same spot and through the entire water column, with exquisite accuracy, by scientists aboard the German research icebreaker Polarstern.

“Our time series confirms the pivotal role of the Southern Ocean and especially the Weddell Sea in terms of storing heat in the depths of the world’s oceans”

“Our data shows a clear division in the water column of the Weddell Sea. While the water in the upper 700 metres has hardly warmed at all, in the deeper regions we’re seeing a consistent temperature rise of 0.0021 to 0.0024 degrees Celsius per year,” said Volker Strass, of the Alfred Wegener Institute in Bremerhaven in Germany.

“Since the ocean has roughly 1,000 times the heat capacity of the atmosphere, these numbers represent an enormous scale of heat absorption. By using the temperature rise to calculate the warming rate in watts per square metre, you can see that over the past 30 years, at depths of over 2,000 metres, the Weddell Sea has absorbed five times as much heat as the rest of the ocean on average.”

The global ocean is the great absorber of atmospheric shock. The deep blue sea has so far absorbed more than nine-tenths of the heat trapped by greenhouse gas emissions in the atmosphere.

The Weddell Sea begins at the extreme south of the Atlantic Ocean: it is roughly 10 times the size of Europe’s North Sea. Here tremendous volumes of water cool down. As sea ice forms on the surface the remaining waters become more salty, and because they have become colder, and denser, sink to the bottom, to spread at depth to drive deep sea flow into the oceans.

Ocean circulation risk

This act of overturning − the sinking of surface waters for thousands of metres into the Antarctic depths − is part of the machinery of ocean circulation that drives and modifies the world’s weather systems, and the climate.

The problem is that if the bottom waters are warming − and are therefore less dense − then this could weaken or stall the mechanism for ocean circulation. In the past 30 years the prevailing winds have shifted and intensified, and the flow speed of ocean water has increased to deliver more heat to the Weddell Sea with each decade.

Warming ocean waters have already been implicated in the loss of sea ice  cover that normally slows the flow of Antarctica’s continental glaciers. And warming in the Arctic has already triggered worries about the future of the “Atlantic Conveyer,” that enormous circulation of water that distributes heat from the Equator to the Poles and keeps northern Europe much warmer than its latitudes would dictate.

“Our time series confirms the pivotal role of the Southern Ocean and especially the Weddell Sea in terms of storing heat in the depths of the world’s oceans,” said Dr Strass. − Climate News Network

Heat from factories and car exhausts must go somewhere. A surprising amount is now sunk in the remote Antarctic depths.

LONDON, 28 October, 2020 − Thanks to global heating, a vital part of the Southern Ocean is warming at a rate five times faster than the average for the Blue Planet as a whole, in the far Antarctic depths: 2000 metres or more below the surface of the Weddell Sea.

It is happening because at that depth the Weddell Sea has absorbed five times as much atmospheric heat − fuelled by greenhouse gas emissions from human fossil fuel combustion − as the average for the rest of the ocean. But what happens out of sight and far below the surface may not stay invisible. The Weddell Sea is where vast volumes of water circulate.

The fear is that such dramatic warming at depth could end up weakening a powerful current that encircles Antarctica, according to a new study in the Journal of Climate.

The evidence comes from 30 years of temperature and salinity samples, taken at the same spot and through the entire water column, with exquisite accuracy, by scientists aboard the German research icebreaker Polarstern.

“Our time series confirms the pivotal role of the Southern Ocean and especially the Weddell Sea in terms of storing heat in the depths of the world’s oceans”

“Our data shows a clear division in the water column of the Weddell Sea. While the water in the upper 700 metres has hardly warmed at all, in the deeper regions we’re seeing a consistent temperature rise of 0.0021 to 0.0024 degrees Celsius per year,” said Volker Strass, of the Alfred Wegener Institute in Bremerhaven in Germany.

“Since the ocean has roughly 1,000 times the heat capacity of the atmosphere, these numbers represent an enormous scale of heat absorption. By using the temperature rise to calculate the warming rate in watts per square metre, you can see that over the past 30 years, at depths of over 2,000 metres, the Weddell Sea has absorbed five times as much heat as the rest of the ocean on average.”

The global ocean is the great absorber of atmospheric shock. The deep blue sea has so far absorbed more than nine-tenths of the heat trapped by greenhouse gas emissions in the atmosphere.

The Weddell Sea begins at the extreme south of the Atlantic Ocean: it is roughly 10 times the size of Europe’s North Sea. Here tremendous volumes of water cool down. As sea ice forms on the surface the remaining waters become more salty, and because they have become colder, and denser, sink to the bottom, to spread at depth to drive deep sea flow into the oceans.

Ocean circulation risk

This act of overturning − the sinking of surface waters for thousands of metres into the Antarctic depths − is part of the machinery of ocean circulation that drives and modifies the world’s weather systems, and the climate.

The problem is that if the bottom waters are warming − and are therefore less dense − then this could weaken or stall the mechanism for ocean circulation. In the past 30 years the prevailing winds have shifted and intensified, and the flow speed of ocean water has increased to deliver more heat to the Weddell Sea with each decade.

Warming ocean waters have already been implicated in the loss of sea ice  cover that normally slows the flow of Antarctica’s continental glaciers. And warming in the Arctic has already triggered worries about the future of the “Atlantic Conveyer,” that enormous circulation of water that distributes heat from the Equator to the Poles and keeps northern Europe much warmer than its latitudes would dictate.

“Our time series confirms the pivotal role of the Southern Ocean and especially the Weddell Sea in terms of storing heat in the depths of the world’s oceans,” said Dr Strass. − Climate News Network

Climate heat melts Arctic snows and dries forests

Fires now blaze under Arctic snows, where once even the wettest rainforests burned. Climate change delivers unlikely outcomes.

LONDON, 12 October, 2020 − The northern polar region isn’t just warming: it’s also smoking, as the rising heat thaws the Arctic snows. Researchers have identified a new class of fire hazard.

High above the Arctic Circle, fires that flared a year ago continued to smoulder under the snow through the winter to flare up again − two months earlier than usual, and on a scale not seen before.

And if the notion of fire and ice seems a surprise, prepare for the idea of a blazing rainforest. In a second and separate study, researchers exploring the climate lessons from the deep past 90 million years ago have found that, if the atmosphere is rich enough in oxygen, then even the wettest foliage can ignite and burn, to consume perhaps up to 40% of the world’s forest.

Scientists from the US report in Nature Geoscience that they have identified an unexpected threat from “zombie fires” which, despite heavy snowmelt, they say “can smoulder in carbon-rich peat below the surface for months or years, often only detectable through smoke released at the surface, and can even occur through cold winter months.”

“The climate change we are causing now, it’s not something where if we don’t fix it, only our grandkids will have to deal with it. The impacts are really long-lasting”

They warn that in the fast-changing climate of the highest northern latitudes, the evidence from last year and this suggest that extreme temperatures and drier conditions mean there is a lot more surface fuel in the Arctic to catch fire and melt the Arctic snows.

Dwarf shrubs, sedges, mosses and grasses are invading the tundra, to join the surface peat, and even the bogs, fens and marches of the tundra are now burning. In all, 50% of the detected fires above 65°North − many in the Russian Arctic − happened on permafrost: that is, on ever-icy soils.

“It’s not just the amount of burned area that is alarming,” said Merritt Turetsky of the University of Colorado at Boulder, and one of the authors. “There are other trends we noticed in the satellite data that tell us how the Arctic fire regime is changing and what this spells for our climate future.”

Wildfires are on the increase now, in a world in which climate change has delivered hotter and drier conditions for many regions. Unexpectedly, according to a second study in Nature Geoscience, fossilized evidence in rocks in Utah has delivered evidence of massive and sustained forest fires, in the form of polycyclic aromatic hydrocarbons preserved in black shales laid down in the Cretaceous.

Huge absorption rate

Researchers pieced together a story of dramatic climate change 94 million years ago, when carbon dioxide built up in the atmosphere, and land and sea plants began to absorb it from the atmosphere on a massive scale. Microbial respiration stepped up too, and parts of the ocean became increasingly low in oxygen.

During 100,000 years of this, so much carbon had been buried in the ground or the oceans that – with the release of molecular oxygen, the O2 in CO2 − atmospheric oxygen levels began to increase. And with that, the scientists say, so did the probability of forest fires, even in wet forest ecosystems. Altogether, perhaps 30% to 40% of the planet’s forests were consumed by fire over 100 millennia.

“One of the consequences of having more oxygen in the atmosphere is that it’s easier to burn fires. It’s the same reason you blow on embers to stoke a fire,” said Garrett Boudinot, then at the University of Boulder Colorado and now with the Colorado Wildlife Council, who led the research.

“This finding highlights the prolonged impacts of climate change. The climate change we are causing now, it’s not something where if we don’t fix it, only our grandkids will have to deal with it. The history of climate change in Earth history tells us that the impacts are really long-lasting.” − Climate News Network

Fires now blaze under Arctic snows, where once even the wettest rainforests burned. Climate change delivers unlikely outcomes.

LONDON, 12 October, 2020 − The northern polar region isn’t just warming: it’s also smoking, as the rising heat thaws the Arctic snows. Researchers have identified a new class of fire hazard.

High above the Arctic Circle, fires that flared a year ago continued to smoulder under the snow through the winter to flare up again − two months earlier than usual, and on a scale not seen before.

And if the notion of fire and ice seems a surprise, prepare for the idea of a blazing rainforest. In a second and separate study, researchers exploring the climate lessons from the deep past 90 million years ago have found that, if the atmosphere is rich enough in oxygen, then even the wettest foliage can ignite and burn, to consume perhaps up to 40% of the world’s forest.

Scientists from the US report in Nature Geoscience that they have identified an unexpected threat from “zombie fires” which, despite heavy snowmelt, they say “can smoulder in carbon-rich peat below the surface for months or years, often only detectable through smoke released at the surface, and can even occur through cold winter months.”

“The climate change we are causing now, it’s not something where if we don’t fix it, only our grandkids will have to deal with it. The impacts are really long-lasting”

They warn that in the fast-changing climate of the highest northern latitudes, the evidence from last year and this suggest that extreme temperatures and drier conditions mean there is a lot more surface fuel in the Arctic to catch fire and melt the Arctic snows.

Dwarf shrubs, sedges, mosses and grasses are invading the tundra, to join the surface peat, and even the bogs, fens and marches of the tundra are now burning. In all, 50% of the detected fires above 65°North − many in the Russian Arctic − happened on permafrost: that is, on ever-icy soils.

“It’s not just the amount of burned area that is alarming,” said Merritt Turetsky of the University of Colorado at Boulder, and one of the authors. “There are other trends we noticed in the satellite data that tell us how the Arctic fire regime is changing and what this spells for our climate future.”

Wildfires are on the increase now, in a world in which climate change has delivered hotter and drier conditions for many regions. Unexpectedly, according to a second study in Nature Geoscience, fossilized evidence in rocks in Utah has delivered evidence of massive and sustained forest fires, in the form of polycyclic aromatic hydrocarbons preserved in black shales laid down in the Cretaceous.

Huge absorption rate

Researchers pieced together a story of dramatic climate change 94 million years ago, when carbon dioxide built up in the atmosphere, and land and sea plants began to absorb it from the atmosphere on a massive scale. Microbial respiration stepped up too, and parts of the ocean became increasingly low in oxygen.

During 100,000 years of this, so much carbon had been buried in the ground or the oceans that – with the release of molecular oxygen, the O2 in CO2 − atmospheric oxygen levels began to increase. And with that, the scientists say, so did the probability of forest fires, even in wet forest ecosystems. Altogether, perhaps 30% to 40% of the planet’s forests were consumed by fire over 100 millennia.

“One of the consequences of having more oxygen in the atmosphere is that it’s easier to burn fires. It’s the same reason you blow on embers to stoke a fire,” said Garrett Boudinot, then at the University of Boulder Colorado and now with the Colorado Wildlife Council, who led the research.

“This finding highlights the prolonged impacts of climate change. The climate change we are causing now, it’s not something where if we don’t fix it, only our grandkids will have to deal with it. The history of climate change in Earth history tells us that the impacts are really long-lasting.” − Climate News Network

Greenland’s ice loss likely to hit 12,000-year high

Greenland’s ice loss could be more this century than at any time in the history of civilization − and perhaps much more.

LONDON, 5 October, 2020 − By the end of this century Greenland’s ice loss will probably be higher than in any century during the last 12,000 years.

Even if humans take immediate drastic action to reduce greenhouse gas emissions, this new record loss will happen. And if − as seems the case − nations go on burning ever more fossil fuels and destroying ever more natural forest, then this ice loss will be four times greater than at any period in human history, according to a new study.

US, Canadian and Danish scientists report in the journal Nature that they used geological evidence and detailed computer simulations to model the past and future loss of ice from the northern hemisphere’s biggest land-borne store − Greenland bears enough ice to raise global sea levels by six metres or more − and measure possible rates of change.

On their reckoning, shortly after the end of the last Ice Age around 12,000 years ago, Greenland’s ice loss was up to 6,000 billion tonnes in the course of 100 years. That, for the entire span from then till now, stayed the record.

They calculate that the rate of loss now, based on measurements in the first 18 years of this century, could still be slightly greater, even if the 195 nations that promised in Paris in 2015 to co-operate to keep global heating to a level “well below” 2°C above the annual average for most of human history, actually kept that promise.

“Our nation has produced more of the CO2 that resides in the atmosphere today than any other country. Americans need to go on an energy diet”

But if the world’s economies continue using fossil fuels under the notorious business-as-usual scenario, then the mass of ice shed from Greenland before the close of the century could be anywhere between 8,800 billion tonnes and 35,900 billion tonnes.

“Basically, we’ve altered our planet so much that the rates of ice sheet melt this century are on pace to be greater than anything we’ve seen under natural variability of the ice sheet over the past 12,000 years.

“We’ll blow that out of the water if we don’t make severe reductions to greenhouse gas emissions,” says Jason Briner, a geologist at the University of Buffalo in New York.

“If the world goes on a massive energy diet,” he adds, “our model predicts that the Greenland Ice Sheet’s rate of mass loss this century will be only slightly higher than anything experienced in the past 12,000 years.”

If on the other hand the world follows what has always been − for climate modellers − the worst case scenario, then, he warns, “the rate of mass loss could be about four times the highest values experienced under natural climate variability over the past 12,000 years.”

‘Eye-opening’ timeline

The latest study supports a flurry of alarming observations and conclusions about Greenland’s ice sheet just in the last few months. Other teams of researchers have found that ice loss from the island is possibly irreversible, that that loss is accelerating in an Arctic region that is warming as fast as or faster than all previous “worst case” predictions, and at a rate that suggests climate scientists may even have to redefine what used to be considered Arctic conditions.

The latest study is one of a series that take the long view of climate history: it is important to separate where possible the effect of natural cycles that would anyway deliver changing conditions, from human-driven or anthropogenic change that could tip the global climate into a new and potentially catastrophic state.

“We have long timelines of temperature change, past to present to future, that show the influence of greenhouse gases on Earth’s temperature. And now, for the first time, we have a long timeline of the impacts of that temperature − in the form of Greenland Ice Sheet melt − from past to present to future. And what it shows is eye-opening,” says Professor Briner.

“Our findings are yet another wake-up call, especially for countries like the US. Americans use more energy per person than any other nation in the world.

“Our nation has produced more of the CO2 that resides in the atmosphere today than any other country. Americans need to go on an energy diet.” − Climate News Network

Greenland’s ice loss could be more this century than at any time in the history of civilization − and perhaps much more.

LONDON, 5 October, 2020 − By the end of this century Greenland’s ice loss will probably be higher than in any century during the last 12,000 years.

Even if humans take immediate drastic action to reduce greenhouse gas emissions, this new record loss will happen. And if − as seems the case − nations go on burning ever more fossil fuels and destroying ever more natural forest, then this ice loss will be four times greater than at any period in human history, according to a new study.

US, Canadian and Danish scientists report in the journal Nature that they used geological evidence and detailed computer simulations to model the past and future loss of ice from the northern hemisphere’s biggest land-borne store − Greenland bears enough ice to raise global sea levels by six metres or more − and measure possible rates of change.

On their reckoning, shortly after the end of the last Ice Age around 12,000 years ago, Greenland’s ice loss was up to 6,000 billion tonnes in the course of 100 years. That, for the entire span from then till now, stayed the record.

They calculate that the rate of loss now, based on measurements in the first 18 years of this century, could still be slightly greater, even if the 195 nations that promised in Paris in 2015 to co-operate to keep global heating to a level “well below” 2°C above the annual average for most of human history, actually kept that promise.

“Our nation has produced more of the CO2 that resides in the atmosphere today than any other country. Americans need to go on an energy diet”

But if the world’s economies continue using fossil fuels under the notorious business-as-usual scenario, then the mass of ice shed from Greenland before the close of the century could be anywhere between 8,800 billion tonnes and 35,900 billion tonnes.

“Basically, we’ve altered our planet so much that the rates of ice sheet melt this century are on pace to be greater than anything we’ve seen under natural variability of the ice sheet over the past 12,000 years.

“We’ll blow that out of the water if we don’t make severe reductions to greenhouse gas emissions,” says Jason Briner, a geologist at the University of Buffalo in New York.

“If the world goes on a massive energy diet,” he adds, “our model predicts that the Greenland Ice Sheet’s rate of mass loss this century will be only slightly higher than anything experienced in the past 12,000 years.”

If on the other hand the world follows what has always been − for climate modellers − the worst case scenario, then, he warns, “the rate of mass loss could be about four times the highest values experienced under natural climate variability over the past 12,000 years.”

‘Eye-opening’ timeline

The latest study supports a flurry of alarming observations and conclusions about Greenland’s ice sheet just in the last few months. Other teams of researchers have found that ice loss from the island is possibly irreversible, that that loss is accelerating in an Arctic region that is warming as fast as or faster than all previous “worst case” predictions, and at a rate that suggests climate scientists may even have to redefine what used to be considered Arctic conditions.

The latest study is one of a series that take the long view of climate history: it is important to separate where possible the effect of natural cycles that would anyway deliver changing conditions, from human-driven or anthropogenic change that could tip the global climate into a new and potentially catastrophic state.

“We have long timelines of temperature change, past to present to future, that show the influence of greenhouse gases on Earth’s temperature. And now, for the first time, we have a long timeline of the impacts of that temperature − in the form of Greenland Ice Sheet melt − from past to present to future. And what it shows is eye-opening,” says Professor Briner.

“Our findings are yet another wake-up call, especially for countries like the US. Americans use more energy per person than any other nation in the world.

“Our nation has produced more of the CO2 that resides in the atmosphere today than any other country. Americans need to go on an energy diet.” − Climate News Network