Tag Archives: Ice melt

Racing ice loss strips Greenland of mass

Greenland is shrinking, losing ice seven times faster than a generation ago. Scientists have taken a new and ominous measure of polar loss.

LONDON, 11 December, 2019 – Greenland – the largest body of frozen water in the northern hemisphere – is now losing ice seven times faster than it did during the last decade of the 20th century.

From 1990 to 1999, the Greenland ice sheet spilled an average of 33 billion tonnes of ice into the oceans every year. In the last decade the rate of loss has accelerated to an average of 254 billion tonnes a year.

Altogether, the Greenland ice cap has surrendered 3.8 trillion tonnes of ice since 1992. This alone is enough to raise global sea levels by 10.6 millimetres.

Glaciers and icecaps are in retreat in two hemispheres, and on every continent, as a consequence of profligate human combustion of fossil fuels, to drive up greenhouse gas levels in the atmosphere, and accelerate global heating.

Devastating

“As a rule of thumb, for every centimetre rise in global sea level another six million people are exposed to coastal flooding around the planet”, said Andrew Shepherd of the University of Leeds in the UK.

“On current trends, Greenland ice melting will cause 100 million people to be flooded each year by the end of the century, so 400 million in total due to all sea level rise. These are not unlikely events of small impacts; they are happening and will be devastating for coastal communities.”

Professor Shepherd is one of 96 polar scientists from 50 international organisations in a partnership known by the cumbrous name IMBIE, which stands for Ice Sheet Mass Balance Intercomparison Exercise. They made this assessment, based on data from 11 satellite missions and 26 separate surveys between 1992 and 2018, and published their conclusions in the journal Nature.

Greenland is not just the largest ice mass in the Arctic, it is probably the polar landscape studied for the longest time, and the most intensively.
Researchers have monitored the rate of summer melt, tried to match increases with other phenomena – for instance the darkening of snow by sub-Arctic wildfires – and tried to explore the mechanisms by which volumes of water that might in the past have frozen again each winter now accelerate glacier melt and escape into the ocean.

No surprise

The icecap is so big that – were it all to melt, which would take centuries – it would raise sea levels by as much as seven metres.

The news of a dramatic increase in rates of melting is not a surprise, and certainly not to the people who live in Greenland.

In 2013, the Intergovernmental Panel on Climate Change warned that global sea levels would rise by 60 cms by 2100. What matters about the latest survey is that it confirms the worst fears of many climate scientists and suggests that sea level rise is heading for the high end of the 2013 projections.

That is, by the end of this century, seas could have risen by nearer 70 cms. Around 100 million people already live at levels below the highest tides: the numbers increasingly at risk may be much higher.

The same study also explores the rates of change. Although the warmest years ever recorded have happened in the last century, as fossil fuel emissions and rainforest losses have continued to increase, the impact of global heating has been uneven.

“Our project is a great example of the importance of international collaboration to tackle problems that are global in scale”

The greatest loss of Greenland ice in any one year was in 2011, when the island lost 335 billion tonnes. Nor does the survey include all the data from 2019, and researchers could yet find that this summer’s ice loss has set new records.

Greenland’s loss of ice has been mirrored by continued loss of sea ice during successive Arctic summers, and since the world’s seasonal weather patterns have – for most of human history – been driven by the temperature difference between tropics and poles, the continued loss of ice will almost certainly impose worldwide costs in harvest losses, freak storms, droughts, wildfires and of course coastal flooding.

And ultimately, the study is a test of computer simulations of change in the northern hemisphere. Climate models have consistently predicted polar ice loss and sea level rise. But the latest study is a confirmation that such loss is real, and beyond argument.

“While computer simulation allows us to make projections from climate change scenarios, the satellite measurements provide prima facie, rather irrefutable evidence,” said Erik Ivins of Nasa’s Jet Propulsion Laboratory in California, and a co-author.

“Our project is a great example of the importance of international collaboration to tackle problems that are global in scale.” – Climate News Network

Greenland is shrinking, losing ice seven times faster than a generation ago. Scientists have taken a new and ominous measure of polar loss.

LONDON, 11 December, 2019 – Greenland – the largest body of frozen water in the northern hemisphere – is now losing ice seven times faster than it did during the last decade of the 20th century.

From 1990 to 1999, the Greenland ice sheet spilled an average of 33 billion tonnes of ice into the oceans every year. In the last decade the rate of loss has accelerated to an average of 254 billion tonnes a year.

Altogether, the Greenland ice cap has surrendered 3.8 trillion tonnes of ice since 1992. This alone is enough to raise global sea levels by 10.6 millimetres.

Glaciers and icecaps are in retreat in two hemispheres, and on every continent, as a consequence of profligate human combustion of fossil fuels, to drive up greenhouse gas levels in the atmosphere, and accelerate global heating.

Devastating

“As a rule of thumb, for every centimetre rise in global sea level another six million people are exposed to coastal flooding around the planet”, said Andrew Shepherd of the University of Leeds in the UK.

“On current trends, Greenland ice melting will cause 100 million people to be flooded each year by the end of the century, so 400 million in total due to all sea level rise. These are not unlikely events of small impacts; they are happening and will be devastating for coastal communities.”

Professor Shepherd is one of 96 polar scientists from 50 international organisations in a partnership known by the cumbrous name IMBIE, which stands for Ice Sheet Mass Balance Intercomparison Exercise. They made this assessment, based on data from 11 satellite missions and 26 separate surveys between 1992 and 2018, and published their conclusions in the journal Nature.

Greenland is not just the largest ice mass in the Arctic, it is probably the polar landscape studied for the longest time, and the most intensively.
Researchers have monitored the rate of summer melt, tried to match increases with other phenomena – for instance the darkening of snow by sub-Arctic wildfires – and tried to explore the mechanisms by which volumes of water that might in the past have frozen again each winter now accelerate glacier melt and escape into the ocean.

No surprise

The icecap is so big that – were it all to melt, which would take centuries – it would raise sea levels by as much as seven metres.

The news of a dramatic increase in rates of melting is not a surprise, and certainly not to the people who live in Greenland.

In 2013, the Intergovernmental Panel on Climate Change warned that global sea levels would rise by 60 cms by 2100. What matters about the latest survey is that it confirms the worst fears of many climate scientists and suggests that sea level rise is heading for the high end of the 2013 projections.

That is, by the end of this century, seas could have risen by nearer 70 cms. Around 100 million people already live at levels below the highest tides: the numbers increasingly at risk may be much higher.

The same study also explores the rates of change. Although the warmest years ever recorded have happened in the last century, as fossil fuel emissions and rainforest losses have continued to increase, the impact of global heating has been uneven.

“Our project is a great example of the importance of international collaboration to tackle problems that are global in scale”

The greatest loss of Greenland ice in any one year was in 2011, when the island lost 335 billion tonnes. Nor does the survey include all the data from 2019, and researchers could yet find that this summer’s ice loss has set new records.

Greenland’s loss of ice has been mirrored by continued loss of sea ice during successive Arctic summers, and since the world’s seasonal weather patterns have – for most of human history – been driven by the temperature difference between tropics and poles, the continued loss of ice will almost certainly impose worldwide costs in harvest losses, freak storms, droughts, wildfires and of course coastal flooding.

And ultimately, the study is a test of computer simulations of change in the northern hemisphere. Climate models have consistently predicted polar ice loss and sea level rise. But the latest study is a confirmation that such loss is real, and beyond argument.

“While computer simulation allows us to make projections from climate change scenarios, the satellite measurements provide prima facie, rather irrefutable evidence,” said Erik Ivins of Nasa’s Jet Propulsion Laboratory in California, and a co-author.

“Our project is a great example of the importance of international collaboration to tackle problems that are global in scale.” – Climate News Network

Greenland ice melt feeds glacier instability

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

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

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

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

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

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

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

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

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

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

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

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

Daily billion-tonne loss

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Daily billion-tonne loss

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

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

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

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

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

New water for old as glaciers vanish

Voids left as glaciers vanish could be used to store spring snowmelt and rainfall to save the valleys below from summer droughts.

LONDON, 4 December, 2019 – Building dams in high mountains to store water as glaciers vanish could produce much-needed hydropower as well as saving people in the valleys below from summer droughts.

Following an earlier study of their own crisis of retreating glaciers in the Alps, Swiss glaciologists have carried out a worldwide study of 185,000 retreating rivers of ice to assess whether the empty valleys they leave behind could usefully be turned into holding dams.

The issue is urgent, because even with an average climate change scenario about three-quarters of the storage potential of these valleys could become ice-free by 2050 – and all of them by the end of the century.

The retreating ice – apart from spelling the end for some magnificent natural monuments – will dramatically affect the water cycle, leaving large river systems with seriously low flows, and some perhaps drying up altogether in the summer. This would have serious consequences for hydro-electricity production, agriculture and even drinking water for cities downstream.

Although water shortage is a potential problem in many high mountain regions, it is already affecting cities like Peru’s capital, Lima, which lies below the Andes. It also has the potential to cause serious problems in India, Pakistan and China, all of them reliant on summer run-off from the Himalayas.

“This theoretical total potential corresponds to about one third of current hydropower production worldwide. But, in reality, only part of it would be realisable”

The idea of the dams would be to capture the water from winter rainfall and spring snowmelt and retain it for gradual release during the summer – so, at least partly, replicating the current summer glacier melt.

ETH Zurich (the Swiss Federal Institute of Technology) and the Swiss Federal Institute for Forest, Snow and Landscape Research report, in a study published in the journal Nature, that the scheme could be viable in many countries.

The team calculated that theoretically the storage potential of these glacier valleys was 875 cubic kilometres of water, providing enormous hydropower potential.

Daniel Farinotti, professor of glaciology at ETH Zurich, who led the team, said: “This theoretical total potential corresponds to about one third of current hydropower production worldwide. But in reality, only part of it would be realisable.”

Since it was neither realistic nor desirable to build a dam in each of the thousands of the valleys vacated by glaciers, the researchers carried out a suitability assessment for all sites.

Significant addition

They identified around 40% of the theoretical total as “potentially” suitable, equalling a storage volume of 355 cubic km and a hydropower potential of 533 TWh per year. The latter corresponds to around 13% of current global hydropower production, or nine times Switzerland’s annual electricity demand.

“Even this potentially suitable storage volume would be sufficient to store about half of the annual runoff from the studied glacierised basins,” Professor Farinotti said.

The results show that basins which have lost their glaciers could contribute significantly to energy supply and water storage in a number of countries, particularly in the high mountain countries of Asia.

Among those with the largest potentials are Tajikistan, where the calculated hydropower potential could account for up to 80% of current electricity consumption, Chile (40%) and Pakistan (35%).

In Canada, Iceland, Bolivia and Norway, the potential equals 10–25% of their current electricity consumption. For Switzerland, the study shows a potential of 10%. – Climate News Network

Voids left as glaciers vanish could be used to store spring snowmelt and rainfall to save the valleys below from summer droughts.

LONDON, 4 December, 2019 – Building dams in high mountains to store water as glaciers vanish could produce much-needed hydropower as well as saving people in the valleys below from summer droughts.

Following an earlier study of their own crisis of retreating glaciers in the Alps, Swiss glaciologists have carried out a worldwide study of 185,000 retreating rivers of ice to assess whether the empty valleys they leave behind could usefully be turned into holding dams.

The issue is urgent, because even with an average climate change scenario about three-quarters of the storage potential of these valleys could become ice-free by 2050 – and all of them by the end of the century.

The retreating ice – apart from spelling the end for some magnificent natural monuments – will dramatically affect the water cycle, leaving large river systems with seriously low flows, and some perhaps drying up altogether in the summer. This would have serious consequences for hydro-electricity production, agriculture and even drinking water for cities downstream.

Although water shortage is a potential problem in many high mountain regions, it is already affecting cities like Peru’s capital, Lima, which lies below the Andes. It also has the potential to cause serious problems in India, Pakistan and China, all of them reliant on summer run-off from the Himalayas.

“This theoretical total potential corresponds to about one third of current hydropower production worldwide. But, in reality, only part of it would be realisable”

The idea of the dams would be to capture the water from winter rainfall and spring snowmelt and retain it for gradual release during the summer – so, at least partly, replicating the current summer glacier melt.

ETH Zurich (the Swiss Federal Institute of Technology) and the Swiss Federal Institute for Forest, Snow and Landscape Research report, in a study published in the journal Nature, that the scheme could be viable in many countries.

The team calculated that theoretically the storage potential of these glacier valleys was 875 cubic kilometres of water, providing enormous hydropower potential.

Daniel Farinotti, professor of glaciology at ETH Zurich, who led the team, said: “This theoretical total potential corresponds to about one third of current hydropower production worldwide. But in reality, only part of it would be realisable.”

Since it was neither realistic nor desirable to build a dam in each of the thousands of the valleys vacated by glaciers, the researchers carried out a suitability assessment for all sites.

Significant addition

They identified around 40% of the theoretical total as “potentially” suitable, equalling a storage volume of 355 cubic km and a hydropower potential of 533 TWh per year. The latter corresponds to around 13% of current global hydropower production, or nine times Switzerland’s annual electricity demand.

“Even this potentially suitable storage volume would be sufficient to store about half of the annual runoff from the studied glacierised basins,” Professor Farinotti said.

The results show that basins which have lost their glaciers could contribute significantly to energy supply and water storage in a number of countries, particularly in the high mountain countries of Asia.

Among those with the largest potentials are Tajikistan, where the calculated hydropower potential could account for up to 80% of current electricity consumption, Chile (40%) and Pakistan (35%).

In Canada, Iceland, Bolivia and Norway, the potential equals 10–25% of their current electricity consumption. For Switzerland, the study shows a potential of 10%. – Climate News Network

Earth nears irreversible tipping points

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

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

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

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

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

Happening now

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

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

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

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

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

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

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

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

Inadequate pledges

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

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

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

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

Timescale controlled

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

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

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

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

Risks multiply

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

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

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

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

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

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

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

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

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

Happening now

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

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

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

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

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

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

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

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

Inadequate pledges

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

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

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

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

Timescale controlled

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

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

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

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

Risks multiply

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

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

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

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

Iceland put people first to save melting economy

Faced in 2008 with a melting economy, Iceland acted fast to avoid total collapse. Icelanders’ own needs were its priority.

LONDON, 27 November, 2019 − What can you do if you’re a smallish island in the North Atlantic with a lot of snow and a melting economy? Quite a lot, it turns out, if you’re prepared to put local people’s needs first.

Iceland was hailed recently for erecting a memorial plaque to one of its most striking features, Okjökull, which shrank so drastically because of climate breakdown that it lost its status as a glacier. It was the first in Iceland to do so, and is now known, fittingly, by a diminutive, as Ok.

Barely 10 years ago, when the country was in the grip of a different crisis, the pace of its far from glacial response showed how quickly rapid changes of government policy can turn a crisis around.

Iceland was at the heart of the global financial crisis in late 2008 and was nearly destroyed by it; 97% of its banking sector collapsed in just three days. its three largest banks − Glitnir, Kaupthing and Landsbankinn − had accumulated a debt of $85 billion (£66bn), equivalent to 10 times the country’s national income (GDP), or 20 times the national budget.

These losses amounted to $330,000 for every man, woman and child on the island, whose stock market then collapsed, with huge numbers of businesses going bankrupt. Iceland approached the International Monetary Fund (IMF) for emergency aid − the first western country to do so since 1976 − and obtained a loan of $2.1bn (£1.4bn).

“It is possible that the Icelandic way of governing also played a part. Was their natural reflex to protect the many, rather than the few?”

So how did it manage to survive? First, it allowed a default on the $85bn in debt accumulated by the banks. A new national mood set in, creating lasting conditions for change and the desire for new economic approaches.

Other countries had largely let banks off the hook, but in 2015 Iceland’s Supreme Court upheld convictions against bankers at the heart of the crisis. Finance is now so sensitive that when the Prime Minister was caught up in revelations from the release of the so-called Panama Papers, he was forced from office.

The debts are now largely paid off, but most multinational businesses have left Iceland, for fear of the capital controls. A huge expansion in tourism has rescued the nation’s economy, though average wages are now much lower.

The government protected Icelanders’ bank deposits and forgave debts for a quarter of the population. As Bloomberg News reported in 2012, “Iceland’s approach to dealing with the meltdown has put the needs of its population ahead of the markets at every turn.”

The Rapid Transition Alliance (RTA), a global initiative which aims to learn from rapid change to address urgent environmental problems, believes Iceland’s way of extricating itself quickly from the global crisis has lessons for other countries, some of which are still paying a heavy price for the events of 2008 and the way they reacted.

Contrary to the conventional wisdom that individual countries cannot independently follow radically different economic policy and control capital flows, says the RTA, Iceland shows they can, and quickly;

Radical change can usher in a virtuous circle, by becoming a habit: once you’ve started, new opportunities may open up for yet more change;

And, perhaps most surprisingly of all, the Alliance says, it is possible to put people before the demands of financial markets and still run a successful economy. Citizen engagement and economic reform can go hand in hand.

Iceland’s economy had thrived on speculative finance but, after the meltdown, rather than making the public pay for the crisis, as the Nobel economist Paul Krugman points out, Iceland “let the banks go bust and actually expanded its social safety net”. Instead of placating financial markets, it introduced temporary controls on the movement of capital to give itself room to manoeuvre.

Following this, a “pots and pans” revolution kick-started a process that led to a new citizen-drafted constitution, which succeeded in engaging half the electorate.

The constitutional exercise proposed a new approach to the ownership of natural resources for the public good, which has had a lasting effect on the country’s choices: all its electricity and heat today comes from renewable sources, and transparency has become a central part of Icelandic public life.

The RTA thinks there were several key factors that enabled such rapid and fundamental change: the extent to which the economic system was irreparably damaged; the decision by the government to respond to the people’s demands and not to those of the banks; and the decision to punish those at fault and start anew.

It concludes: “It is possible that the Icelandic way of governing also played a part, because they have a longstanding history of deeply embedded democracy and a culture that discourages hierarchy. Was their natural reflex to protect the many, rather than the few?” − Climate News Network

* * * * *

The Rapid Transition Alliance is coordinated by the New Weather Institute, the STEPS Centre at the Institute of  Development Studies, and the School of Global Studies at the University of Sussex, UK. The Climate News Network is partnering with and supported by the Rapid Transition Alliance, and will be reporting regularly on its work. If you would like to see more stories of evidence-based hope for rapid transition, please sign up here.

Do you know a story of rapid transition? If so, we’d like to hear from you. Please send us a brief outline on info@climatenewsnetwork.net. Thank you.

Faced in 2008 with a melting economy, Iceland acted fast to avoid total collapse. Icelanders’ own needs were its priority.

LONDON, 27 November, 2019 − What can you do if you’re a smallish island in the North Atlantic with a lot of snow and a melting economy? Quite a lot, it turns out, if you’re prepared to put local people’s needs first.

Iceland was hailed recently for erecting a memorial plaque to one of its most striking features, Okjökull, which shrank so drastically because of climate breakdown that it lost its status as a glacier. It was the first in Iceland to do so, and is now known, fittingly, by a diminutive, as Ok.

Barely 10 years ago, when the country was in the grip of a different crisis, the pace of its far from glacial response showed how quickly rapid changes of government policy can turn a crisis around.

Iceland was at the heart of the global financial crisis in late 2008 and was nearly destroyed by it; 97% of its banking sector collapsed in just three days. its three largest banks − Glitnir, Kaupthing and Landsbankinn − had accumulated a debt of $85 billion (£66bn), equivalent to 10 times the country’s national income (GDP), or 20 times the national budget.

These losses amounted to $330,000 for every man, woman and child on the island, whose stock market then collapsed, with huge numbers of businesses going bankrupt. Iceland approached the International Monetary Fund (IMF) for emergency aid − the first western country to do so since 1976 − and obtained a loan of $2.1bn (£1.4bn).

“It is possible that the Icelandic way of governing also played a part. Was their natural reflex to protect the many, rather than the few?”

So how did it manage to survive? First, it allowed a default on the $85bn in debt accumulated by the banks. A new national mood set in, creating lasting conditions for change and the desire for new economic approaches.

Other countries had largely let banks off the hook, but in 2015 Iceland’s Supreme Court upheld convictions against bankers at the heart of the crisis. Finance is now so sensitive that when the Prime Minister was caught up in revelations from the release of the so-called Panama Papers, he was forced from office.

The debts are now largely paid off, but most multinational businesses have left Iceland, for fear of the capital controls. A huge expansion in tourism has rescued the nation’s economy, though average wages are now much lower.

The government protected Icelanders’ bank deposits and forgave debts for a quarter of the population. As Bloomberg News reported in 2012, “Iceland’s approach to dealing with the meltdown has put the needs of its population ahead of the markets at every turn.”

The Rapid Transition Alliance (RTA), a global initiative which aims to learn from rapid change to address urgent environmental problems, believes Iceland’s way of extricating itself quickly from the global crisis has lessons for other countries, some of which are still paying a heavy price for the events of 2008 and the way they reacted.

Contrary to the conventional wisdom that individual countries cannot independently follow radically different economic policy and control capital flows, says the RTA, Iceland shows they can, and quickly;

Radical change can usher in a virtuous circle, by becoming a habit: once you’ve started, new opportunities may open up for yet more change;

And, perhaps most surprisingly of all, the Alliance says, it is possible to put people before the demands of financial markets and still run a successful economy. Citizen engagement and economic reform can go hand in hand.

Iceland’s economy had thrived on speculative finance but, after the meltdown, rather than making the public pay for the crisis, as the Nobel economist Paul Krugman points out, Iceland “let the banks go bust and actually expanded its social safety net”. Instead of placating financial markets, it introduced temporary controls on the movement of capital to give itself room to manoeuvre.

Following this, a “pots and pans” revolution kick-started a process that led to a new citizen-drafted constitution, which succeeded in engaging half the electorate.

The constitutional exercise proposed a new approach to the ownership of natural resources for the public good, which has had a lasting effect on the country’s choices: all its electricity and heat today comes from renewable sources, and transparency has become a central part of Icelandic public life.

The RTA thinks there were several key factors that enabled such rapid and fundamental change: the extent to which the economic system was irreparably damaged; the decision by the government to respond to the people’s demands and not to those of the banks; and the decision to punish those at fault and start anew.

It concludes: “It is possible that the Icelandic way of governing also played a part, because they have a longstanding history of deeply embedded democracy and a culture that discourages hierarchy. Was their natural reflex to protect the many, rather than the few?” − Climate News Network

* * * * *

The Rapid Transition Alliance is coordinated by the New Weather Institute, the STEPS Centre at the Institute of  Development Studies, and the School of Global Studies at the University of Sussex, UK. The Climate News Network is partnering with and supported by the Rapid Transition Alliance, and will be reporting regularly on its work. If you would like to see more stories of evidence-based hope for rapid transition, please sign up here.

Do you know a story of rapid transition? If so, we’d like to hear from you. Please send us a brief outline on info@climatenewsnetwork.net. Thank you.

Arctic’s oldest ice shows signs of change

There’s change afoot even where scientists least expect it, among the Arctic’s oldest ice. If it goes, so does the wildlife.

LONDON, 21 November, 2019 – Stretches of the Arctic’s oldest ice, and its thickest – the last refuge ice that should survive even when the Arctic Ocean technically becomes ice-free in summers later this century – are now disappearing twice as fast as the rest of the Arctic icecap.

Although the north polar ice is vulnerable to global heating, and has been thinning and retreating at an accelerating rate for the last 40 summers, researchers have always expected some winter ice to survive: they define an “ice-free Arctic Ocean” as one with less than 1 million square kilometres of surviving ice pack.

But this supposedly ancient remnant of the polar winters, concentrated north of Greenland and the Canadian polar archipelago, is showing signs of change.

Researchers do not explicitly finger climate change driven by ever-greater human use of fossil fuels as the direct agent of this change: this is an area of polar ice difficult to observe and explore, is little known, and may always have been subject to change.

“This area will be a refuge where species can survive and hopefully expand their regions once the ice starts returning”

But scientists know why it is important. From submarine algae to polar bears, an entire Arctic ecosystem is dependent on the ice sheet. As the ice disappears, so will the seals, and their predators too.

Conservation-minded governments that want to establish protected areas need to know where protection will work best. “Eventually, the Last Ice Area will be the region that will repopulate the Arctic with wildlife,” said Kent Moore of the University of Toronto in Canada. “This area will be a refuge where species can survive and hopefully expand their regions once the ice starts returning.”

Dr Moore and his colleagues report in the journal Geophysical Research Letters that they used computer models and satellite observation data to build up a picture of what they call “spatiotemporal variability” in their Last Ice Area.

They found two distinct places where ice thickness fluctuated by up to 1.2 metres from year to year. In some patches, the ice was thinning by the decade: a loss of 1.5 metres since the late 1970s.

No monolith

Most north polar ice is youthful: seldom more than four years old. The Last Ice Area is certainly more than five years old, and has been measured at a thickness of four metres. It is not a static region: ice moves with the ocean beneath it.

And even the levels of melting are affected by natural cyclic ocean shifts as well as higher temperatures fuelled by greenhouse gas build-up in the atmosphere.

The race is on to understand the forces at work in what might be – one day – the only surviving ice in the polar summer.

“We can’t treat the Last Ice Area as a monolithic area of ice which is going to last a long time,” said Dr Moore. “There’s actually lots of regional variability.” – Climate News Network

There’s change afoot even where scientists least expect it, among the Arctic’s oldest ice. If it goes, so does the wildlife.

LONDON, 21 November, 2019 – Stretches of the Arctic’s oldest ice, and its thickest – the last refuge ice that should survive even when the Arctic Ocean technically becomes ice-free in summers later this century – are now disappearing twice as fast as the rest of the Arctic icecap.

Although the north polar ice is vulnerable to global heating, and has been thinning and retreating at an accelerating rate for the last 40 summers, researchers have always expected some winter ice to survive: they define an “ice-free Arctic Ocean” as one with less than 1 million square kilometres of surviving ice pack.

But this supposedly ancient remnant of the polar winters, concentrated north of Greenland and the Canadian polar archipelago, is showing signs of change.

Researchers do not explicitly finger climate change driven by ever-greater human use of fossil fuels as the direct agent of this change: this is an area of polar ice difficult to observe and explore, is little known, and may always have been subject to change.

“This area will be a refuge where species can survive and hopefully expand their regions once the ice starts returning”

But scientists know why it is important. From submarine algae to polar bears, an entire Arctic ecosystem is dependent on the ice sheet. As the ice disappears, so will the seals, and their predators too.

Conservation-minded governments that want to establish protected areas need to know where protection will work best. “Eventually, the Last Ice Area will be the region that will repopulate the Arctic with wildlife,” said Kent Moore of the University of Toronto in Canada. “This area will be a refuge where species can survive and hopefully expand their regions once the ice starts returning.”

Dr Moore and his colleagues report in the journal Geophysical Research Letters that they used computer models and satellite observation data to build up a picture of what they call “spatiotemporal variability” in their Last Ice Area.

They found two distinct places where ice thickness fluctuated by up to 1.2 metres from year to year. In some patches, the ice was thinning by the decade: a loss of 1.5 metres since the late 1970s.

No monolith

Most north polar ice is youthful: seldom more than four years old. The Last Ice Area is certainly more than five years old, and has been measured at a thickness of four metres. It is not a static region: ice moves with the ocean beneath it.

And even the levels of melting are affected by natural cyclic ocean shifts as well as higher temperatures fuelled by greenhouse gas build-up in the atmosphere.

The race is on to understand the forces at work in what might be – one day – the only surviving ice in the polar summer.

“We can’t treat the Last Ice Area as a monolithic area of ice which is going to last a long time,” said Dr Moore. “There’s actually lots of regional variability.” – Climate News Network

Warming forces world of ice into retreat

warming

New evidence from the air, space, atmospheric chemistry and old records is testament to global warming impacts on the speed of change in the frozen world.

LONDON, October, 21, 2019 – Just as Scottish scientists deliver dramatic visual evidence of the retreat of Europe’s most famous glacier over the course of a century because of global warming, German scientists have mapped an even more devastating retreat of Andean glaciers in just 16 years.

In another demonstration of the impact of warming on what had always been considered the cryosphere, the world of ice and snow, Swedish scientists have shown that the chemistry of the northern forests has begun to change in ways that could even accelerate rising temperatures.

And in the US, researchers have shown that winter is on the wane and the snows in retreat – with dramatic consequences for wildlife, water supplies and human wealth and health.

Warming faster

All four studies are further confirmation of what climate scientists have already shown – that the high latitudes and high altitudes are warming faster than almost anywhere else on the planet, with ominous consequences.

In August 1919, pioneer aviator Walter Mittelholzer flew near the summit of Mont Blanc in Europe in a biplane to photograph Europe’s highest peak and the Mer de Glace glacier, one of the great tourist attractions and celebrated by artists and poets for two centuries

Exactly one century later, researchers from the University of Dundee in Scotland used global positioning satellite guidance and digital help to take a helicopter to exactly the same position and altitude of 4,700 metres to repeat the 1919 aerial study.

“It was both a breathtaking and heartbreaking experience, particularly knowing that the melt has accelerated massively in the last few decades”

Kieran Baxter, aerial photographer, digital media practitioner and researcher at the University of Dundee, says: “The scale of ice loss was immediately evident as we reached altitude, but it was only by comparing the images side by side that the last 100 years of change were made visible.

“It was both a breathtaking and heartbreaking experience, particularly knowing that the melt has accelerated massively in the last few decades.”

Glaciers store rainy season ice and snow, and release it as meltwater in the hot dry summers. They keep the rivers flowing, the crops growing, and the hydroelectric turbines turning.

Scientists from the University of Erlangen-Nuremberg in Germany report in the The Cryosphere journal that they used satellite imagery to calculate glacier loss in Peru this century.

Almost three-quarters of all tropical glaciers and 90% of their area of ice are concentrated in the Peruvian Andes, at around 4000 metres or more.

At the beginning of this century, there had been a count of 1,973 rivers of ice in the region. Of these, 170 have vanished altogether, while the others have retreated uphill, and their accumulated area has dwindled by around 550 square kilometres.

Loss of ice mass

Eight billion tonnes of ice have melted away, and at an ever-faster rate. The loss of ice mass between 2013 and 2016 was around four times higher than in the previous 12 years, perhaps because of local climate changes triggered by a periodic climate phenomenon known worldwide as an El Niño.

Glaciers are an important part of the climate machine, but the great forests that flourish in the snows below them are even more important.

They add up to 14% of the planet’s vegetation coverage, they absorb atmospheric carbon to cool the climate in one way, and counter the greenhouse gases that fuel global warming in another, subtle way. The conifers exude terpene aerosols – the pine-fresh fragrance from their resins – that have a cooling effect on the air over the forests.

But scientists from Sweden report in Nature Communications journal that, thanks to atmospheric pollution driven by global agriculture and industrialisation, the terpene particles from the forests are getting smaller in diameter – some smaller than a wavelength of optical light.

That means that the same particles are now less effective at reflecting solar radiation back into space. Ammonia and sulphur dioxide discharged by humankind have changed the chemistry of the forests: there are now more aerosols, but their diameter is dwindling.

Study leader Pontus Rodin, a researcher at Lund University, Sweden, says: “The heavily-oxidized organic molecules have a cooling effect on the climate. With a warmer climate, it is expected that forests will release more terpenes, and thus create more cooling organic aerosols.

“However, the extent of that effect also depends on the emission volumes of sulphur dioxide and ammonia in the future. It’s very clear, though, that this increase in organic aerosols cannot by any means compensate for the warming of the climate caused by our emissions of greenhouse gases.”

Weather station data

And while European scientists examined the detail of loss, scientists in the US looked at 100 years of weather station data from the forests of the US and Canada.

They report in Ecological Applications journal that they found a significant decline in the number of “frost days” when the temperature dropped below freezing, and “ice days” in which the thermometer stayed below freezing.

Snow and ice sustain ecosystems by preventing disease spread and reducing beetle and aphid numbers. Deep snow insulates tree roots, provides wildlife habitat, and promotes soil nutrient recycling.

“Winter conditions are changing more rapidly than any other season, and it could have serious implications,” says Alexandra Contosta, assistant professor in the Earth Systems Research Centre at the University of New Hampshire.

“Whether precipitation falls as snow or rain makes a big difference, whether you are talking about a forest stream, a snowshoe hare, or even a skier.” –Climate News Network

New evidence from the air, space, atmospheric chemistry and old records is testament to global warming impacts on the speed of change in the frozen world.

LONDON, October, 21, 2019 – Just as Scottish scientists deliver dramatic visual evidence of the retreat of Europe’s most famous glacier over the course of a century because of global warming, German scientists have mapped an even more devastating retreat of Andean glaciers in just 16 years.

In another demonstration of the impact of warming on what had always been considered the cryosphere, the world of ice and snow, Swedish scientists have shown that the chemistry of the northern forests has begun to change in ways that could even accelerate rising temperatures.

And in the US, researchers have shown that winter is on the wane and the snows in retreat – with dramatic consequences for wildlife, water supplies and human wealth and health.

Warming faster

All four studies are further confirmation of what climate scientists have already shown – that the high latitudes and high altitudes are warming faster than almost anywhere else on the planet, with ominous consequences.

In August 1919, pioneer aviator Walter Mittelholzer flew near the summit of Mont Blanc in Europe in a biplane to photograph Europe’s highest peak and the Mer de Glace glacier, one of the great tourist attractions and celebrated by artists and poets for two centuries

Exactly one century later, researchers from the University of Dundee in Scotland used global positioning satellite guidance and digital help to take a helicopter to exactly the same position and altitude of 4,700 metres to repeat the 1919 aerial study.

“It was both a breathtaking and heartbreaking experience, particularly knowing that the melt has accelerated massively in the last few decades”

Kieran Baxter, aerial photographer, digital media practitioner and researcher at the University of Dundee, says: “The scale of ice loss was immediately evident as we reached altitude, but it was only by comparing the images side by side that the last 100 years of change were made visible.

“It was both a breathtaking and heartbreaking experience, particularly knowing that the melt has accelerated massively in the last few decades.”

Glaciers store rainy season ice and snow, and release it as meltwater in the hot dry summers. They keep the rivers flowing, the crops growing, and the hydroelectric turbines turning.

Scientists from the University of Erlangen-Nuremberg in Germany report in the The Cryosphere journal that they used satellite imagery to calculate glacier loss in Peru this century.

Almost three-quarters of all tropical glaciers and 90% of their area of ice are concentrated in the Peruvian Andes, at around 4000 metres or more.

At the beginning of this century, there had been a count of 1,973 rivers of ice in the region. Of these, 170 have vanished altogether, while the others have retreated uphill, and their accumulated area has dwindled by around 550 square kilometres.

Loss of ice mass

Eight billion tonnes of ice have melted away, and at an ever-faster rate. The loss of ice mass between 2013 and 2016 was around four times higher than in the previous 12 years, perhaps because of local climate changes triggered by a periodic climate phenomenon known worldwide as an El Niño.

Glaciers are an important part of the climate machine, but the great forests that flourish in the snows below them are even more important.

They add up to 14% of the planet’s vegetation coverage, they absorb atmospheric carbon to cool the climate in one way, and counter the greenhouse gases that fuel global warming in another, subtle way. The conifers exude terpene aerosols – the pine-fresh fragrance from their resins – that have a cooling effect on the air over the forests.

But scientists from Sweden report in Nature Communications journal that, thanks to atmospheric pollution driven by global agriculture and industrialisation, the terpene particles from the forests are getting smaller in diameter – some smaller than a wavelength of optical light.

That means that the same particles are now less effective at reflecting solar radiation back into space. Ammonia and sulphur dioxide discharged by humankind have changed the chemistry of the forests: there are now more aerosols, but their diameter is dwindling.

Study leader Pontus Rodin, a researcher at Lund University, Sweden, says: “The heavily-oxidized organic molecules have a cooling effect on the climate. With a warmer climate, it is expected that forests will release more terpenes, and thus create more cooling organic aerosols.

“However, the extent of that effect also depends on the emission volumes of sulphur dioxide and ammonia in the future. It’s very clear, though, that this increase in organic aerosols cannot by any means compensate for the warming of the climate caused by our emissions of greenhouse gases.”

Weather station data

And while European scientists examined the detail of loss, scientists in the US looked at 100 years of weather station data from the forests of the US and Canada.

They report in Ecological Applications journal that they found a significant decline in the number of “frost days” when the temperature dropped below freezing, and “ice days” in which the thermometer stayed below freezing.

Snow and ice sustain ecosystems by preventing disease spread and reducing beetle and aphid numbers. Deep snow insulates tree roots, provides wildlife habitat, and promotes soil nutrient recycling.

“Winter conditions are changing more rapidly than any other season, and it could have serious implications,” says Alexandra Contosta, assistant professor in the Earth Systems Research Centre at the University of New Hampshire.

“Whether precipitation falls as snow or rain makes a big difference, whether you are talking about a forest stream, a snowshoe hare, or even a skier.” –Climate News Network

‘Upside-down rivers’ speed polar ice loss

polar ice

Researchers move closer to understanding the invisible dynamics that drive the loss of polar ice shelves – but what it means for global warming is still uncertain.

LONDON, October 16, 2019 – Scientists in the US believe they have now identified the machinery that drives the break-up of great chunks of polar ice shelves. What they call “upside down rivers” of warm, less dense, less saline water, tens of miles long and miles wide, find weaknesses in the massive ice shelves.

And because global temperature rise is causing polar currents to get warmer, the effect could be to accelerate the collapse of great tracts of ice shelf, and allow glacial flow to speed up – resulting in rising sea levels.

Call it subversion: these unexpected channels of water rise from underneath to concentrate their effect on fracture zones that form as land-bound glaciers flow slowly onto the marine surface.

“Warm water circulation is attacking the undersides of these ice shelves at their weakest points,” says Earth scientist Karen Alley, who did her research at the University of Colorado in Boulder, but is now at the College of Wooster in Ohio, US. “These effects matter. Exactly how much, we don’t yet know. But we need to.”

Frozen sheets

The research could explain the persistent appearance, at roughly the same place every year, of polynyas. These are great pools of open sea water in the ice shelves, and scientists have been puzzling for decades about the mechanisms that make them possible.

About 80% of Antarctica is bounded by frozen sheets of sea ice, many of them anchored by bumps and chasms on the sea floor, and this is what slows the flow of ice from high ground to ocean.

But satellite studies have long exposed crevasses in this ice, formed at what scientists call “shear margins” – weak points in flowing ice.

Once part of the floating shelf, these fracture zones are more vulnerable to plumes of more buoyant – that is, less saline and warmer – water that flow as “basal channels” to create long wrinkles or sags in the shelf.

Dr Alley and her colleagues report in Science Advances journal that they pieced together this picture of polar dynamism far below the surface by combing satellite data to expose patterns of surface change made possible only by some consistent erosion by warmer current.

Climate – winds, rainfall, heat and drought patterns – is driven by the temperature gradient. Large-scale weather systems happen because the poles are cold and the tropics are hot, and this difference powers the stratospheric jet stream and the most profound ocean flow.

So climate scientists are intensely interested in change in both Greenland and the Antarctic.

“Now we’re seeing a new process, where warm water cuts into the ice shelf from below”

Other teams have already established that ice shelves are melting ever faster in the coldest places on the planet, that this melting is happening ever faster, that the ice is being attacked from below, and that this can only accelerate sea-level rise in a world subject to global heating driven by human use of fossil fuels that deposit huge volumes of greenhouse gases in the atmosphere.

The latest study focused on Antarctica, but the findings could also be applied to Greenland, which has the greatest reserve of Arctic ice, and where ice loss is accelerating even faster.

Report co-author Ted Scambos, senior research scientist in the Earth Science and Observation Centre at the University of Colorado at Boulder, says: “Now we’re seeing a new process, where warm water cuts into the ice shelf from below.

“Like scoring a plate of glass, the trough renders the shelf weak and, in a few decades, it’s gone, freeing the ice sheet to ride out faster into the ocean.” – Climate News Network

Researchers move closer to understanding the invisible dynamics that drive the loss of polar ice shelves – but what it means for global warming is still uncertain.

LONDON, October 16, 2019 – Scientists in the US believe they have now identified the machinery that drives the break-up of great chunks of polar ice shelves. What they call “upside down rivers” of warm, less dense, less saline water, tens of miles long and miles wide, find weaknesses in the massive ice shelves.

And because global temperature rise is causing polar currents to get warmer, the effect could be to accelerate the collapse of great tracts of ice shelf, and allow glacial flow to speed up – resulting in rising sea levels.

Call it subversion: these unexpected channels of water rise from underneath to concentrate their effect on fracture zones that form as land-bound glaciers flow slowly onto the marine surface.

“Warm water circulation is attacking the undersides of these ice shelves at their weakest points,” says Earth scientist Karen Alley, who did her research at the University of Colorado in Boulder, but is now at the College of Wooster in Ohio, US. “These effects matter. Exactly how much, we don’t yet know. But we need to.”

Frozen sheets

The research could explain the persistent appearance, at roughly the same place every year, of polynyas. These are great pools of open sea water in the ice shelves, and scientists have been puzzling for decades about the mechanisms that make them possible.

About 80% of Antarctica is bounded by frozen sheets of sea ice, many of them anchored by bumps and chasms on the sea floor, and this is what slows the flow of ice from high ground to ocean.

But satellite studies have long exposed crevasses in this ice, formed at what scientists call “shear margins” – weak points in flowing ice.

Once part of the floating shelf, these fracture zones are more vulnerable to plumes of more buoyant – that is, less saline and warmer – water that flow as “basal channels” to create long wrinkles or sags in the shelf.

Dr Alley and her colleagues report in Science Advances journal that they pieced together this picture of polar dynamism far below the surface by combing satellite data to expose patterns of surface change made possible only by some consistent erosion by warmer current.

Climate – winds, rainfall, heat and drought patterns – is driven by the temperature gradient. Large-scale weather systems happen because the poles are cold and the tropics are hot, and this difference powers the stratospheric jet stream and the most profound ocean flow.

So climate scientists are intensely interested in change in both Greenland and the Antarctic.

“Now we’re seeing a new process, where warm water cuts into the ice shelf from below”

Other teams have already established that ice shelves are melting ever faster in the coldest places on the planet, that this melting is happening ever faster, that the ice is being attacked from below, and that this can only accelerate sea-level rise in a world subject to global heating driven by human use of fossil fuels that deposit huge volumes of greenhouse gases in the atmosphere.

The latest study focused on Antarctica, but the findings could also be applied to Greenland, which has the greatest reserve of Arctic ice, and where ice loss is accelerating even faster.

Report co-author Ted Scambos, senior research scientist in the Earth Science and Observation Centre at the University of Colorado at Boulder, says: “Now we’re seeing a new process, where warm water cuts into the ice shelf from below.

“Like scoring a plate of glass, the trough renders the shelf weak and, in a few decades, it’s gone, freeing the ice sheet to ride out faster into the ocean.” – Climate News Network

Penguins in peril as winds change and heat rises

New weather patterns in the warming Antarctic are leaving thousands of penguins in peril, prompting calls for them to be specially protected.

LONDON, 10 October, 2019 – A species that has come to symbolise Antarctica’s wealth of wildlife now faces mortal danger: climate change is putting emperor penguins in peril.

British scientists say the continent is warming with unparalleled speed, meaning the birds may soon have almost nowhere to breed. Some researchers think the number of emperors could be cut by more than half by 2100.

Philip Trathan, head of conservation biology at the British Antarctic Survey in Cambridge, says: “The current rate of warming in parts of the Antarctic is greater than anything in the recent glaciological record.

“Though emperor penguins have experienced periods of warming and cooling over their evolutionary history, the current rates of warming are unprecedented.

“Currently, we have no idea how the emperors will adjust to the loss of their primary breeding habitat – sea ice. They are not agile, and climbing ashore across steep coastal land forms will be difficult.

Numbers fluctuate

“For breeding, they depend upon sea ice, and in a warming world there is a high probability that this will decrease. Without it, they will have little or no breeding habitat.”

It is not the first time scientists have sounded the alarm for the emperors. This time, though, they are urging potentially far-reaching action.

In a study published in the journal Biological Conservation, an international team of researchers, led by Dr Trathan, recommends new steps to protect and conserve the penguins (Aptenodytes forsteri).

Satellite images in 2012 suggested there were almost 600,000 of the birds in the Antarctic, roughly double the number estimated in 1992. The researchers involved in this latest report reviewed over 150 studies on the species and its environment as well as its behaviour and character in relation to its breeding biology.

“Some colonies of emperor penguins may not survive the coming decades, so we must work to give as much protection as we can to the species”

Current climate change projections indicate that rising temperatures and changing wind patterns will damage the sea ice on which the emperors breed, with some studies showing populations likely to fall by more than 50% over this century.

Before breeding, both males and females must build their body reserves so that females can lay their single egg, and for males to fast while undertaking the entire egg incubation during the Antarctic winter.

Emperors are unique amongst birds because they breed on seasonal Antarctic sea ice which they need while incubating their eggs and raising their chicks.

They also need stable sea ice after they have completed breeding, during the time when they undergo their annual moult. They cannot enter the water then as their feathers are no longer waterproof, leaving them unable to enter the sea.

So the researchers are recommending that the IUCN status for the species be raised from “near-threatened” to “vulnerable” on the IUCN Red List.  They say improvements in climate change forecasting of impacts on Antarctic wildlife would help, and recommend that the emperors should be listed by the Antarctic Treaty as a specially protected species.

Wider appeal

Better protection will let scientists coordinate research into the penguins’ resilience to a range of different threats and stressors.

Dr Peter Fretwell, remote sensing specialist at BAS and a co-author of the study, says: “Some colonies of emperor penguins may not survive the coming decades, so we must work to give as much protection as we can to the species to give them the best chance.”

The UK was one of the countries which notified the Antarctic Treaty Consultative Meeting at its 2019 meeting in July that emperor penguins were threatened by the loss of their breeding habitat and that further protection was needed.

A similar paper has also been submitted to this year’s Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR), which meets in the Tasmanian capital, Hobart, later this month. – Climate News Network 

New weather patterns in the warming Antarctic are leaving thousands of penguins in peril, prompting calls for them to be specially protected.

LONDON, 10 October, 2019 – A species that has come to symbolise Antarctica’s wealth of wildlife now faces mortal danger: climate change is putting emperor penguins in peril.

British scientists say the continent is warming with unparalleled speed, meaning the birds may soon have almost nowhere to breed. Some researchers think the number of emperors could be cut by more than half by 2100.

Philip Trathan, head of conservation biology at the British Antarctic Survey in Cambridge, says: “The current rate of warming in parts of the Antarctic is greater than anything in the recent glaciological record.

“Though emperor penguins have experienced periods of warming and cooling over their evolutionary history, the current rates of warming are unprecedented.

“Currently, we have no idea how the emperors will adjust to the loss of their primary breeding habitat – sea ice. They are not agile, and climbing ashore across steep coastal land forms will be difficult.

Numbers fluctuate

“For breeding, they depend upon sea ice, and in a warming world there is a high probability that this will decrease. Without it, they will have little or no breeding habitat.”

It is not the first time scientists have sounded the alarm for the emperors. This time, though, they are urging potentially far-reaching action.

In a study published in the journal Biological Conservation, an international team of researchers, led by Dr Trathan, recommends new steps to protect and conserve the penguins (Aptenodytes forsteri).

Satellite images in 2012 suggested there were almost 600,000 of the birds in the Antarctic, roughly double the number estimated in 1992. The researchers involved in this latest report reviewed over 150 studies on the species and its environment as well as its behaviour and character in relation to its breeding biology.

“Some colonies of emperor penguins may not survive the coming decades, so we must work to give as much protection as we can to the species”

Current climate change projections indicate that rising temperatures and changing wind patterns will damage the sea ice on which the emperors breed, with some studies showing populations likely to fall by more than 50% over this century.

Before breeding, both males and females must build their body reserves so that females can lay their single egg, and for males to fast while undertaking the entire egg incubation during the Antarctic winter.

Emperors are unique amongst birds because they breed on seasonal Antarctic sea ice which they need while incubating their eggs and raising their chicks.

They also need stable sea ice after they have completed breeding, during the time when they undergo their annual moult. They cannot enter the water then as their feathers are no longer waterproof, leaving them unable to enter the sea.

So the researchers are recommending that the IUCN status for the species be raised from “near-threatened” to “vulnerable” on the IUCN Red List.  They say improvements in climate change forecasting of impacts on Antarctic wildlife would help, and recommend that the emperors should be listed by the Antarctic Treaty as a specially protected species.

Wider appeal

Better protection will let scientists coordinate research into the penguins’ resilience to a range of different threats and stressors.

Dr Peter Fretwell, remote sensing specialist at BAS and a co-author of the study, says: “Some colonies of emperor penguins may not survive the coming decades, so we must work to give as much protection as we can to the species to give them the best chance.”

The UK was one of the countries which notified the Antarctic Treaty Consultative Meeting at its 2019 meeting in July that emperor penguins were threatened by the loss of their breeding habitat and that further protection was needed.

A similar paper has also been submitted to this year’s Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR), which meets in the Tasmanian capital, Hobart, later this month. – Climate News Network 

Extreme sea level events ‘will hit once a year by 2050’

This story originally appeared in The Guardian. It is republished here as part of the Climate News Network’s partnership with Covering Climate Now, a global collaboration of more than 250 news outlets to strengthen coverage of the climate story.

Extreme sea level events that used to occur once a century will strike every year on many coasts by 2050, no matter whether climate heating emissions are curbed or not, according to a landmark report by the world’s scientists.

25 September, 2019 − The stark assessment of the climate crisis in the world’s oceans and ice caps concludes that many serious impacts are already inevitable, from more intense storms to melting permafrost and dwindling marine life.

But far worse impacts will hit without urgent action to cut fossil fuel emissions, including eventual sea level rise of more than 4 metres in the worst case, an outcome that would redraw the map of the world and harm billions of people.

The report from the Intergovernmental Panel on Climate Change (IPCC), and approved by its 193 member nations, says that “all people on Earth depend directly or indirectly on the ocean” and ice caps and glaciers to regulate the climate and provide water and oxygen. But it finds unprecedented and dangerous changes being driven by global heating.

Sea level rise is accelerating as losses from Greenland and Antarctica increase, and the ocean is getting hotter, more acidic and less oxygenated. All these trends will continue to the end of the century, the IPCC report said.

Half the world’s megacities, and almost 2 billion people, live on coasts. Even if heating is restricted to just 2C, scientists expect the impact of sea level rise to cause several trillion dollars of damage a year, and result in many millions of migrants.

“The future for low-lying coastal communities looks extremely bleak,” said Prof Jonathan Bamber at Bristol University in the UK, who is not one of the report’s authors. “But the consequences will be felt by all of us. There is plenty to be concerned about for the future of humanity and social order from the headlines in this report.”

The new IPCC projections of likely sea level rise by 2100 are higher than those it made in 2014, due to unexpectedly fast melting in Antarctica. Without cuts in carbon emissions, the ocean is expected to rise between 61cm and 110cm, about 10cm more than the earlier estimate. A 10cm rise means 10 million additional people exposed to flooding, research shows.

The IPCC considers the likely range of sea level rise but not the worst-case scenario. Recent expert analysis led by Bamber concluded that up to 238cm of sea level rise remains possible by 2100, drowning many megacities around the world. “This cannot be ruled out,” said Zita Sebesvari at the United Nations University, a lead author of the IPCC report.

Even if huge cuts in emissions begin immediately, between 29cm and 59cm of sea level rise is already inevitable because the ice caps and glaciers melt slowly. Sea level will rise for centuries without action, Sebesvari warned. “The dramatic thing about sea level rise is if we accept 1 metre happening by 2100, we accept we will get about 4 metres by 2300. That is simply not an option we can risk.”

Extreme sea level impacts will be felt in many places very soon and well before 2050, Sebesvari said. The IPCC report states: “Extreme sea level events that [occur] once per century in the recent past are projected to occur at least once per year at many locations by 2050 in all scenarios.”

The heating oceans are causing more intense tropical storms to batter coasts, the IPCC report found, with stronger winds and greater deluges of rain. For example, Hurricane Harvey’s unprecedented deluge, which caused catastrophic flooding, was made three times more likely by climate change.

Ocean heating also harms kelp forests and other important ecosystems, with the marine heatwaves that sear through them like underwater wildfires having doubled in frequency in the last 40 years. They are projected to increase by at least 20 times by 2100, the IPCC reported.

Extreme El Niño events, which see heatwaves in some regions and floods in others, are projected to occur twice as often this century whether emissions are cut or not, the report said. Coral reefs, vital nurseries for marine life, will suffer major losses and local extinctions. Across the ocean, heat, acidification and lower oxygen is set to cut fisheries by a quarter and all marine life by 15% if emissions are not slashed.

The IPCC report also records the large reduction in Arctic ice. This loss exacerbates global heating, because the exposed darker ocean absorbs more heat from the sun than highly reflective ice. On Monday, scientists announced that the Arctic sea ice in 2019 shrank to its second lowest extent in the 41-year satellite record.

The world’s high mountain glaciers, upon which almost 2 billion people rely for water, are also melting fast, the IPCC found, while landslides are expected to increase. A third of the great Himalayan range is already doomed, with two-thirds projected to vanish if emissions are not cut.

One of the most worrying alarms sounded by the IPCC report is about melting tundra and increasing wildfires in northern latitudes: “Widespread permafrost thaw is projected for this century and beyond.” A quarter is already near certain to melt, it said, and 70% or more would go if emissions are not curbed. In the latter case, hundreds of billions of tonnes of carbon dioxide and methane could be released, supercharging the climate emergency.

“That risks taking us beyond the point where climate change could be easily constrained,” said Richard Black, at the UK’s Energy and Climate Intelligence Unit. “Nevertheless, the IPCC’s 2018 report concluded that governments can shrink emissions quickly enough to keep global warming to 1.5C if they choose. None can claim to be unaware of both the dangers of untrammelled climate change nor the feasibility of preventing it.”

Anne Hidalgo, the mayor of Paris and chair of the C40 Cities climate coalition, said the IPCC report was shocking. “Around 1.9 billion people and over half of the world’s megacities are all in grave danger if we don’t act immediately. Several cities, home to hundreds of thousands of people, are already disappearing underwater. This is what the climate crisis looks like now.”

Taehyun Park, of Greenpeace East Asia, said: “The science is both chilling and compelling. The impacts on our oceans are on a much larger scale and happening way faster than predicted. It will require unprecedented political action to prevent the most severe consequences to our planet.”

As well as cutting fossil fuel emissions, preparing for the inevitable impacts is also vital, said Sebesvari, especially in poorer nations that lack the funds to build sea walls, move settlements or restore protective coastal marshes.

“Action is needed now to secure the coast for our children and coming generations,” she said. The pressure now being exerted by the global school strikes for climate was important, she said. “I have very strong motivation. I have two kids and we are really being tested by our kids on our actions.”

* * * * * * *

Damian Carrington is The Guardian’s environment editor.

This story originally appeared in The Guardian. It is republished here as part of the Climate News Network’s partnership with Covering Climate Now, a global collaboration of more than 250 news outlets to strengthen coverage of the climate story.

Extreme sea level events that used to occur once a century will strike every year on many coasts by 2050, no matter whether climate heating emissions are curbed or not, according to a landmark report by the world’s scientists.

25 September, 2019 − The stark assessment of the climate crisis in the world’s oceans and ice caps concludes that many serious impacts are already inevitable, from more intense storms to melting permafrost and dwindling marine life.

But far worse impacts will hit without urgent action to cut fossil fuel emissions, including eventual sea level rise of more than 4 metres in the worst case, an outcome that would redraw the map of the world and harm billions of people.

The report from the Intergovernmental Panel on Climate Change (IPCC), and approved by its 193 member nations, says that “all people on Earth depend directly or indirectly on the ocean” and ice caps and glaciers to regulate the climate and provide water and oxygen. But it finds unprecedented and dangerous changes being driven by global heating.

Sea level rise is accelerating as losses from Greenland and Antarctica increase, and the ocean is getting hotter, more acidic and less oxygenated. All these trends will continue to the end of the century, the IPCC report said.

Half the world’s megacities, and almost 2 billion people, live on coasts. Even if heating is restricted to just 2C, scientists expect the impact of sea level rise to cause several trillion dollars of damage a year, and result in many millions of migrants.

“The future for low-lying coastal communities looks extremely bleak,” said Prof Jonathan Bamber at Bristol University in the UK, who is not one of the report’s authors. “But the consequences will be felt by all of us. There is plenty to be concerned about for the future of humanity and social order from the headlines in this report.”

The new IPCC projections of likely sea level rise by 2100 are higher than those it made in 2014, due to unexpectedly fast melting in Antarctica. Without cuts in carbon emissions, the ocean is expected to rise between 61cm and 110cm, about 10cm more than the earlier estimate. A 10cm rise means 10 million additional people exposed to flooding, research shows.

The IPCC considers the likely range of sea level rise but not the worst-case scenario. Recent expert analysis led by Bamber concluded that up to 238cm of sea level rise remains possible by 2100, drowning many megacities around the world. “This cannot be ruled out,” said Zita Sebesvari at the United Nations University, a lead author of the IPCC report.

Even if huge cuts in emissions begin immediately, between 29cm and 59cm of sea level rise is already inevitable because the ice caps and glaciers melt slowly. Sea level will rise for centuries without action, Sebesvari warned. “The dramatic thing about sea level rise is if we accept 1 metre happening by 2100, we accept we will get about 4 metres by 2300. That is simply not an option we can risk.”

Extreme sea level impacts will be felt in many places very soon and well before 2050, Sebesvari said. The IPCC report states: “Extreme sea level events that [occur] once per century in the recent past are projected to occur at least once per year at many locations by 2050 in all scenarios.”

The heating oceans are causing more intense tropical storms to batter coasts, the IPCC report found, with stronger winds and greater deluges of rain. For example, Hurricane Harvey’s unprecedented deluge, which caused catastrophic flooding, was made three times more likely by climate change.

Ocean heating also harms kelp forests and other important ecosystems, with the marine heatwaves that sear through them like underwater wildfires having doubled in frequency in the last 40 years. They are projected to increase by at least 20 times by 2100, the IPCC reported.

Extreme El Niño events, which see heatwaves in some regions and floods in others, are projected to occur twice as often this century whether emissions are cut or not, the report said. Coral reefs, vital nurseries for marine life, will suffer major losses and local extinctions. Across the ocean, heat, acidification and lower oxygen is set to cut fisheries by a quarter and all marine life by 15% if emissions are not slashed.

The IPCC report also records the large reduction in Arctic ice. This loss exacerbates global heating, because the exposed darker ocean absorbs more heat from the sun than highly reflective ice. On Monday, scientists announced that the Arctic sea ice in 2019 shrank to its second lowest extent in the 41-year satellite record.

The world’s high mountain glaciers, upon which almost 2 billion people rely for water, are also melting fast, the IPCC found, while landslides are expected to increase. A third of the great Himalayan range is already doomed, with two-thirds projected to vanish if emissions are not cut.

One of the most worrying alarms sounded by the IPCC report is about melting tundra and increasing wildfires in northern latitudes: “Widespread permafrost thaw is projected for this century and beyond.” A quarter is already near certain to melt, it said, and 70% or more would go if emissions are not curbed. In the latter case, hundreds of billions of tonnes of carbon dioxide and methane could be released, supercharging the climate emergency.

“That risks taking us beyond the point where climate change could be easily constrained,” said Richard Black, at the UK’s Energy and Climate Intelligence Unit. “Nevertheless, the IPCC’s 2018 report concluded that governments can shrink emissions quickly enough to keep global warming to 1.5C if they choose. None can claim to be unaware of both the dangers of untrammelled climate change nor the feasibility of preventing it.”

Anne Hidalgo, the mayor of Paris and chair of the C40 Cities climate coalition, said the IPCC report was shocking. “Around 1.9 billion people and over half of the world’s megacities are all in grave danger if we don’t act immediately. Several cities, home to hundreds of thousands of people, are already disappearing underwater. This is what the climate crisis looks like now.”

Taehyun Park, of Greenpeace East Asia, said: “The science is both chilling and compelling. The impacts on our oceans are on a much larger scale and happening way faster than predicted. It will require unprecedented political action to prevent the most severe consequences to our planet.”

As well as cutting fossil fuel emissions, preparing for the inevitable impacts is also vital, said Sebesvari, especially in poorer nations that lack the funds to build sea walls, move settlements or restore protective coastal marshes.

“Action is needed now to secure the coast for our children and coming generations,” she said. The pressure now being exerted by the global school strikes for climate was important, she said. “I have very strong motivation. I have two kids and we are really being tested by our kids on our actions.”

* * * * * * *

Damian Carrington is The Guardian’s environment editor.