Tag Archives: Glaciers

Little time left to arrest Greenland’s melting

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

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

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

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

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

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

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

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

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

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

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

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

Triggers identified

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Triggers identified

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

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

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

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

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

Heat the Arctic to cool the Earth, scientists say

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

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

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

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

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

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

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

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

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

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

More heat escapes

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

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

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

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

Unknown consequences

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

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

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

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

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

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

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

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

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

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

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

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

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

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

More heat escapes

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

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

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

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

Unknown consequences

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

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

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

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

Glacial melt creates Andes time bomb

The speed of glacial melt in parts of Latin America is threatening water supplies – and life and limb in cities downstream.

LONDON, 16 December, 2019 – Rising regional temperatures in the Andes and the warming of waters in the Pacific Ocean, off Latin America’s west coast, are driving the mountains’ glacial melt to alarming new speeds.

Long-term water supplies to many millions of people are under threat. Capital cities like Lima in Peru and La Paz in Bolivia, largely dependent on water from glacier melt flows, face an uncertain future.

The prospects for agriculture – a mainstay of the economies of countries in the region – will be imperilled as land dries up.

There is another, potentially lethal consequence of the melting of the Andes’ glaciers. In 1941, large chunks of ice breaking off a glacier and falling into Lake Palcacocha, more than 4,500 metres up in the Cordillera Blanca mountain range in the Peruvian Andes, are said to have triggered what’s known as a glacial lake outburst flood (GLOF).

“As temperatures in the region continue to rise, the danger level increases”

The sudden influx of ice caused the lake to burst, its waters racing down a canyon to burst another glacial lake below and then on to flood the city of Huarez, more than 20 kilometres away. It’s estimated that more than 4,000 people – about a third of the city’s population at the time – were killed.

Rising temperatures caused by climate change in mountain ranges around the world are leading to an ever-increasing number of GLOF incidents. Mountainous countries like Peru and Nepal, in the Himalayas, are particularly vulnerable to the sudden flooding caused when glacial lakes burst.

In the aftermath of the 1941 flood, a dam was built on Lake Palcacocha: at first the lake slowly refilled, but in recent years the process accelerated due to increased temperatures and more glacial melt.

Flexible pipes have been used to siphon waters off from the lake but experts say it’s only a matter of time before Lake Palcacocha again bursts its banks. The dam, they say, will be swept away. The consequences would be devastating as a wave up to 30 metres tall is unleashed.

Increased population

The city of Huarez has become a big tourist destination and its population has grown to more than 120,000. Large numbers of farmers have moved onto lands below Lake Palcacocha. Mine workers are also active in the area, searching for valuable minerals in ground uncovered by the melting of the glaciers.

Various safety measures are being installed. After years of wrangling and bureaucratic delays, a flood early warning system is about to be activated in the area.

Installation of the system has also been subject to sabotage by local farmers who say that the introduction of the technology has somehow interfered with natural weather patterns.

Monitoring systems have improved – with often daily glacial avalanches being recorded. Inaigem, the national research institute on glaciers and mountain ecosystems, provides a live video of Lake Palcacocha water flows. But as temperatures in the region continue to rise, the danger level increases. – Climate News Network

The speed of glacial melt in parts of Latin America is threatening water supplies – and life and limb in cities downstream.

LONDON, 16 December, 2019 – Rising regional temperatures in the Andes and the warming of waters in the Pacific Ocean, off Latin America’s west coast, are driving the mountains’ glacial melt to alarming new speeds.

Long-term water supplies to many millions of people are under threat. Capital cities like Lima in Peru and La Paz in Bolivia, largely dependent on water from glacier melt flows, face an uncertain future.

The prospects for agriculture – a mainstay of the economies of countries in the region – will be imperilled as land dries up.

There is another, potentially lethal consequence of the melting of the Andes’ glaciers. In 1941, large chunks of ice breaking off a glacier and falling into Lake Palcacocha, more than 4,500 metres up in the Cordillera Blanca mountain range in the Peruvian Andes, are said to have triggered what’s known as a glacial lake outburst flood (GLOF).

“As temperatures in the region continue to rise, the danger level increases”

The sudden influx of ice caused the lake to burst, its waters racing down a canyon to burst another glacial lake below and then on to flood the city of Huarez, more than 20 kilometres away. It’s estimated that more than 4,000 people – about a third of the city’s population at the time – were killed.

Rising temperatures caused by climate change in mountain ranges around the world are leading to an ever-increasing number of GLOF incidents. Mountainous countries like Peru and Nepal, in the Himalayas, are particularly vulnerable to the sudden flooding caused when glacial lakes burst.

In the aftermath of the 1941 flood, a dam was built on Lake Palcacocha: at first the lake slowly refilled, but in recent years the process accelerated due to increased temperatures and more glacial melt.

Flexible pipes have been used to siphon waters off from the lake but experts say it’s only a matter of time before Lake Palcacocha again bursts its banks. The dam, they say, will be swept away. The consequences would be devastating as a wave up to 30 metres tall is unleashed.

Increased population

The city of Huarez has become a big tourist destination and its population has grown to more than 120,000. Large numbers of farmers have moved onto lands below Lake Palcacocha. Mine workers are also active in the area, searching for valuable minerals in ground uncovered by the melting of the glaciers.

Various safety measures are being installed. After years of wrangling and bureaucratic delays, a flood early warning system is about to be activated in the area.

Installation of the system has also been subject to sabotage by local farmers who say that the introduction of the technology has somehow interfered with natural weather patterns.

Monitoring systems have improved – with often daily glacial avalanches being recorded. Inaigem, the national research institute on glaciers and mountain ecosystems, provides a live video of Lake Palcacocha water flows. But as temperatures in the region continue to rise, the danger level increases. – Climate News Network

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

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.

New land height metric raises sea level rise risk

Millions of us now live in danger: we could be at risk from future high tides and winds, says a new approach to measuring land height.

 

LONDON, 4 November, 2019 – Researchers have taken a closer look at estimates of coastal land height – and found that the numbers of people already at risk from sea level rise driven by global heating have multiplied threefold.

More than 100 million people already live below the high tide line, and 250 million live on plains that are lower than the current annual flood heights. Previous estimates have put these numbers at 28 million, and 65 million.

And even if the world takes immediate drastic action and reduces greenhouse gas emissions by the end of the century, at least 190 million people will find themselves below sea level.

If the world’s nations continue on the notorious business-as-usual track and go on burning ever greater volumes of fossil fuels, then around 630 million will, by the year 2100, find themselves on land that will be below the expected annual flood levels.

Protection in question

“These assessments show the potential of climate change to reshape cities, economies, coastlines and entire global regions within our lifetime,” said Scott Kulp of Climate Central, who led a study published in the journal Nature Communications.

“As the tideline rises higher than the ground people call home, nations will increasingly confront questions about whether, how much, and how long coastal defences can protect them.”

At the heart of the new research is a revised estimate of what constitutes sea level, and how it should be measured. Individuals and communities find out the hard way how the highest tides can rise to poison their farmlands with salt and wash away the foundations of their homes.

But the big picture – across nations and regions worldwide – is harder to estimate: for decades researchers have relied on satellite readings, confirmed by flights over limited spaces with radar equipment.

“There is still a great need for . . . more accurate elevation data. Lives and livelihoods depend on it”

But space-based readings by Nasa’s radar topography programme tend to be over-estimates, the researchers argue. That is because the technology measures the height of the first reflecting surface the radar signal touches. In open country, this may not matter. But forests and high buildings in densely-peopled cities distort the picture.

In parts of coastal Australia, and using a new approach, the researchers found that satellite readings delivered over-estimates of 2.5 metres. So global averages in the past have over-estimated, by around 2 metres, the elevation of lands that are home to billions.

Research of this kind helps clarify the challenge that faces governments, civic authorities and private citizens: communities grow up along low-lying coasts and estuaries because these provide good land, reliable water supplies and easy transport. But the catch with flood plains is that, sooner or later, they flood.

The repeated evidence of a decade of climate science is that floods will become more devastating, more frequent and more prolonged for a mix of reasons.

Multiple risks

Soils will subside because of the growing demand for groundwater and for clays and stone for bricks and mortar; because global average temperatures will rise and oceans expand as they warm; glaciers will melt and tip more water into the sea to raise ocean levels; and tropical cyclones will become more intense to drive more destructive storm surges.

Researchers have already warned that sea level rise could be accelerating, to bring more flooding to, for instance, the great cities of the US coasts, while some cities can expect ever more battering from Atlantic storms.

Coastal flooding is likely to create millions of climate refugees even within the US, and the worldwide costs of coastal flooding could reach $1 trillion a year by the end of the century.

The latest study confirms that the hazards are real, and may have so far been under-estimated. The researchers calculated that, in parts of China, Bangladesh, India, Vietnam and Thailand, places now home to 237 million people could face coastal flooding every year by 2050 – a figure 183 million higher than previous estimates.

US coasts threatened

The same study highlights faulty estimates of ground elevation even in the richest and most advanced nations. In some parts of the crowded coastal cities of New York, Boston and Miami, for instance, the researchers believe satellite readings have over-estimated ground height by almost five metres. They say their new approach reduces the margin of error to 2.5 cms.

Right now, around a billion people live on lands less than 10 metres above high tide levels. Around 250 million live within one metre above high tide.

“For all of the critical research that’s been done on climate change and sea level projections, it turns out that for most of the global coast we didn’t know the height of the ground beneath our feet,” said Benjamin Strauss, president and chief scientist of Climate Central, and co-author.

“Our data improves the picture, but there is still a great need for governments and insurance companies to produce and release more accurate elevation data. Lives and livelihoods depend on it.” – Climate News Network

Millions of us now live in danger: we could be at risk from future high tides and winds, says a new approach to measuring land height.

 

LONDON, 4 November, 2019 – Researchers have taken a closer look at estimates of coastal land height – and found that the numbers of people already at risk from sea level rise driven by global heating have multiplied threefold.

More than 100 million people already live below the high tide line, and 250 million live on plains that are lower than the current annual flood heights. Previous estimates have put these numbers at 28 million, and 65 million.

And even if the world takes immediate drastic action and reduces greenhouse gas emissions by the end of the century, at least 190 million people will find themselves below sea level.

If the world’s nations continue on the notorious business-as-usual track and go on burning ever greater volumes of fossil fuels, then around 630 million will, by the year 2100, find themselves on land that will be below the expected annual flood levels.

Protection in question

“These assessments show the potential of climate change to reshape cities, economies, coastlines and entire global regions within our lifetime,” said Scott Kulp of Climate Central, who led a study published in the journal Nature Communications.

“As the tideline rises higher than the ground people call home, nations will increasingly confront questions about whether, how much, and how long coastal defences can protect them.”

At the heart of the new research is a revised estimate of what constitutes sea level, and how it should be measured. Individuals and communities find out the hard way how the highest tides can rise to poison their farmlands with salt and wash away the foundations of their homes.

But the big picture – across nations and regions worldwide – is harder to estimate: for decades researchers have relied on satellite readings, confirmed by flights over limited spaces with radar equipment.

“There is still a great need for . . . more accurate elevation data. Lives and livelihoods depend on it”

But space-based readings by Nasa’s radar topography programme tend to be over-estimates, the researchers argue. That is because the technology measures the height of the first reflecting surface the radar signal touches. In open country, this may not matter. But forests and high buildings in densely-peopled cities distort the picture.

In parts of coastal Australia, and using a new approach, the researchers found that satellite readings delivered over-estimates of 2.5 metres. So global averages in the past have over-estimated, by around 2 metres, the elevation of lands that are home to billions.

Research of this kind helps clarify the challenge that faces governments, civic authorities and private citizens: communities grow up along low-lying coasts and estuaries because these provide good land, reliable water supplies and easy transport. But the catch with flood plains is that, sooner or later, they flood.

The repeated evidence of a decade of climate science is that floods will become more devastating, more frequent and more prolonged for a mix of reasons.

Multiple risks

Soils will subside because of the growing demand for groundwater and for clays and stone for bricks and mortar; because global average temperatures will rise and oceans expand as they warm; glaciers will melt and tip more water into the sea to raise ocean levels; and tropical cyclones will become more intense to drive more destructive storm surges.

Researchers have already warned that sea level rise could be accelerating, to bring more flooding to, for instance, the great cities of the US coasts, while some cities can expect ever more battering from Atlantic storms.

Coastal flooding is likely to create millions of climate refugees even within the US, and the worldwide costs of coastal flooding could reach $1 trillion a year by the end of the century.

The latest study confirms that the hazards are real, and may have so far been under-estimated. The researchers calculated that, in parts of China, Bangladesh, India, Vietnam and Thailand, places now home to 237 million people could face coastal flooding every year by 2050 – a figure 183 million higher than previous estimates.

US coasts threatened

The same study highlights faulty estimates of ground elevation even in the richest and most advanced nations. In some parts of the crowded coastal cities of New York, Boston and Miami, for instance, the researchers believe satellite readings have over-estimated ground height by almost five metres. They say their new approach reduces the margin of error to 2.5 cms.

Right now, around a billion people live on lands less than 10 metres above high tide levels. Around 250 million live within one metre above high tide.

“For all of the critical research that’s been done on climate change and sea level projections, it turns out that for most of the global coast we didn’t know the height of the ground beneath our feet,” said Benjamin Strauss, president and chief scientist of Climate Central, and co-author.

“Our data improves the picture, but there is still a great need for governments and insurance companies to produce and release more accurate elevation data. Lives and livelihoods depend on it.” – 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