Tag Archives: Sea levels

Extreme sea levels could soon become annual events

Extreme sea levels are inevitable. Researchers now know more about their scale. Prepare for high tides almost every year.

LONDON, 8 September, 2021 − Those who live by the sea could soon enough be at risk from it. Extreme sea levels − those episodes of high tide, storm surge and coastal flood − that now happen only once in every century could within a lifetime be happening every year.

And this is increasingly likely even if nations act on promises made six years ago and make drastic reductions in fossil fuel use. The global warming already inevitable because of the last decades of greenhouse gas emissions makes frequent flooding ever more likely.

US, European and Australian researchers report in the journal Nature Climate Change that they used computer projections to model what would be likely to happen to sea levels at 7,283 coastal locations worldwide over the next 70 years, under a range of scenarios that saw global temperatures rise to between 1.5°C and 5°C.

The bad news is that at least half of them face a massive increase in the frequency of extreme episodes by 2070.

“How much warming will it take to make a 100-year event an annual event? Not much more than what has already been documented”

The most vulnerable regions will be in the tropics and subtropics, including the Mediterranean Sea, the Arabian Peninsula, the southern part of North America’s Pacific Coast, Hawaii and the Caribbean, the Philippines, Indonesia and much of the southern hemisphere.

“One of our central questions driving this study was this: how much warming will it take to make what has been known as a 100-year event an annual event? Our answer is, not much more than what has already been documented,” said Claudia Tebaldi, of the Pacific Northwest National Laboratory in the US.

In the last century, the world has warmed by at least one degree Celsius above the average for most of human history: in 2015, in Paris, 195 nations vowed to contain global temperature rise to “well below” 2°C by 2100, and ideally to no more than 1.5°C. That promise has yet to be backed up by concerted, dramatic international action.

In fact, the planet could surpass the 1.5°C limit, at least temporarily, some time this decade. Within 70 years, at present rates of emissions, the world will be committed to a potentially catastrophic global average rise of 3°C.

Warmth in store

And, researchers have warned, and warned again, coastal flooding could reach devastating levels. So the latest study simply confirms an alarming future, and adds a little more certainty to the zones more at risk.

The research is also a reminder that although drastic cuts and a concerted effort to restore the natural world could limit the rise in global air temperatures, the world’s oceans are subject to a slower timetable: the warming that has already happened will increasingly be reflected in tide levels for decades to come.

Like all such projections, the potential outcome ranges from optimistic to very pessimistic. With a temperature rise of just 1.5°C, seven-tenths of the studied locations might experience little increase in flood frequency. At the gloomier end of the spectrum, 99% could see flooding multiply 100-fold.

“It’s not huge news that sea level rise will be dramatic even at 1.5°C and will have substantial effects on extreme sea level frequencies and magnitude,” Dr Tebaldi said. “This study gives a more complete picture around the globe. We were able to look at a wider range of warming levels in fine spatial detail.” − Climate News Network

Extreme sea levels are inevitable. Researchers now know more about their scale. Prepare for high tides almost every year.

LONDON, 8 September, 2021 − Those who live by the sea could soon enough be at risk from it. Extreme sea levels − those episodes of high tide, storm surge and coastal flood − that now happen only once in every century could within a lifetime be happening every year.

And this is increasingly likely even if nations act on promises made six years ago and make drastic reductions in fossil fuel use. The global warming already inevitable because of the last decades of greenhouse gas emissions makes frequent flooding ever more likely.

US, European and Australian researchers report in the journal Nature Climate Change that they used computer projections to model what would be likely to happen to sea levels at 7,283 coastal locations worldwide over the next 70 years, under a range of scenarios that saw global temperatures rise to between 1.5°C and 5°C.

The bad news is that at least half of them face a massive increase in the frequency of extreme episodes by 2070.

“How much warming will it take to make a 100-year event an annual event? Not much more than what has already been documented”

The most vulnerable regions will be in the tropics and subtropics, including the Mediterranean Sea, the Arabian Peninsula, the southern part of North America’s Pacific Coast, Hawaii and the Caribbean, the Philippines, Indonesia and much of the southern hemisphere.

“One of our central questions driving this study was this: how much warming will it take to make what has been known as a 100-year event an annual event? Our answer is, not much more than what has already been documented,” said Claudia Tebaldi, of the Pacific Northwest National Laboratory in the US.

In the last century, the world has warmed by at least one degree Celsius above the average for most of human history: in 2015, in Paris, 195 nations vowed to contain global temperature rise to “well below” 2°C by 2100, and ideally to no more than 1.5°C. That promise has yet to be backed up by concerted, dramatic international action.

In fact, the planet could surpass the 1.5°C limit, at least temporarily, some time this decade. Within 70 years, at present rates of emissions, the world will be committed to a potentially catastrophic global average rise of 3°C.

Warmth in store

And, researchers have warned, and warned again, coastal flooding could reach devastating levels. So the latest study simply confirms an alarming future, and adds a little more certainty to the zones more at risk.

The research is also a reminder that although drastic cuts and a concerted effort to restore the natural world could limit the rise in global air temperatures, the world’s oceans are subject to a slower timetable: the warming that has already happened will increasingly be reflected in tide levels for decades to come.

Like all such projections, the potential outcome ranges from optimistic to very pessimistic. With a temperature rise of just 1.5°C, seven-tenths of the studied locations might experience little increase in flood frequency. At the gloomier end of the spectrum, 99% could see flooding multiply 100-fold.

“It’s not huge news that sea level rise will be dramatic even at 1.5°C and will have substantial effects on extreme sea level frequencies and magnitude,” Dr Tebaldi said. “This study gives a more complete picture around the globe. We were able to look at a wider range of warming levels in fine spatial detail.” − Climate News Network

Ireland faces future of climate change division

Ireland, known as the Emerald Isle for its verdant pastures, may soon lose its title as climate change division takes hold.

DUBLIN, 17 August, 2021 − A friend emails from Athens, describing brown, smoke-filled skies caused by Greece’s raging fires, and says she dreams of soft Irish rain. Little does she know of the growing climate change division which is splitting the island apart.

The brother, living in northern California, talks of temperatures yet again topping 40°C, and driving along highways and hearing the macabre, crackling sound of burning forests.

“What I wouldn’t give for a breath of fresh Irish air”, he says.

Ireland, blessed with a temperate climate, little polluting heavy industry and a relatively small population, has so far escaped most of the extremes of climate change.

While many countries in southern Europe in recent months have been hit by record high temperatures, drought and wildfires, and several states in northern Europe have endured torrential rain and floods, Ireland has been unscathed.

Semi-tropical Ireland

But a new report on the country’s climate – the most comprehensive such study in more than eight years – warns that Ireland is not immune to the dramatic changes happening elsewhere.

The study, by the government’s Environmental Protection Agency (EPA)  and Met Éireann, the national meteorological service, warns of coming weather extremes.

Trends point to “more intense, almost tropical rainfall events.” Couched in cautious terms, the study says scientists in Ireland are “more certain” that the country is becoming both wetter and warmer.

The report says annual rainfall has increased by 6% over the last 30 years compared with the 1960 to 1990 period, while annual average temperatures in Ireland have increased by 0.9% over the past 120 years. The seas round Ireland are becoming warmer and are rising – by approximately 2 to 3mm a year since the early 1990s.

“What I wouldn’t give for a breath of fresh Irish air”

A lack of rainfall is not a phenomenon usually associated with Ireland, but the study warns that, despite the increase in total amounts of precipitation, drought could hit many areas in coming years.

The climate is effectively dividing the country in half: rivers in the west and north of the country are becoming fuller, leading to an increased risk of serious flooding. But in the east and south – where the majority of the population lives – some rivers are at risk of drying up.

Frank McGovern, the EPA’s chief scientist, told the Irish Times that government policies need to take account of the country’s changing rainfall patterns: the study’s findings “should inform investment in planning and making our infrastructure and population more resilient to climate change.”

Ireland markets itself as a green and unpolluted land, free of the smoking industrial chimneys of much of the developed world.

Judicial rebuke

The reality is different: per head of population, Ireland is one of the leading emitters of climate-changing greenhouse gases (GHGs) in Europe.

Its agricultural sector – a key part of the economy – is responsible for a large portion of those emissions.

Problems caused by GHG emissions from the country’s seven million cattle herd and by nitrate-based fertilisers are only slowly being tackled. Ireland’s transport sector is also a big polluter.

Last year Ireland’s Supreme Court, the country’s highest judicial authority, described the Dublin government’s climate policies as “excessively vague and aspirational” and lacking in clear plans and goals. − Climate News Network

Ireland, known as the Emerald Isle for its verdant pastures, may soon lose its title as climate change division takes hold.

DUBLIN, 17 August, 2021 − A friend emails from Athens, describing brown, smoke-filled skies caused by Greece’s raging fires, and says she dreams of soft Irish rain. Little does she know of the growing climate change division which is splitting the island apart.

The brother, living in northern California, talks of temperatures yet again topping 40°C, and driving along highways and hearing the macabre, crackling sound of burning forests.

“What I wouldn’t give for a breath of fresh Irish air”, he says.

Ireland, blessed with a temperate climate, little polluting heavy industry and a relatively small population, has so far escaped most of the extremes of climate change.

While many countries in southern Europe in recent months have been hit by record high temperatures, drought and wildfires, and several states in northern Europe have endured torrential rain and floods, Ireland has been unscathed.

Semi-tropical Ireland

But a new report on the country’s climate – the most comprehensive such study in more than eight years – warns that Ireland is not immune to the dramatic changes happening elsewhere.

The study, by the government’s Environmental Protection Agency (EPA)  and Met Éireann, the national meteorological service, warns of coming weather extremes.

Trends point to “more intense, almost tropical rainfall events.” Couched in cautious terms, the study says scientists in Ireland are “more certain” that the country is becoming both wetter and warmer.

The report says annual rainfall has increased by 6% over the last 30 years compared with the 1960 to 1990 period, while annual average temperatures in Ireland have increased by 0.9% over the past 120 years. The seas round Ireland are becoming warmer and are rising – by approximately 2 to 3mm a year since the early 1990s.

“What I wouldn’t give for a breath of fresh Irish air”

A lack of rainfall is not a phenomenon usually associated with Ireland, but the study warns that, despite the increase in total amounts of precipitation, drought could hit many areas in coming years.

The climate is effectively dividing the country in half: rivers in the west and north of the country are becoming fuller, leading to an increased risk of serious flooding. But in the east and south – where the majority of the population lives – some rivers are at risk of drying up.

Frank McGovern, the EPA’s chief scientist, told the Irish Times that government policies need to take account of the country’s changing rainfall patterns: the study’s findings “should inform investment in planning and making our infrastructure and population more resilient to climate change.”

Ireland markets itself as a green and unpolluted land, free of the smoking industrial chimneys of much of the developed world.

Judicial rebuke

The reality is different: per head of population, Ireland is one of the leading emitters of climate-changing greenhouse gases (GHGs) in Europe.

Its agricultural sector – a key part of the economy – is responsible for a large portion of those emissions.

Problems caused by GHG emissions from the country’s seven million cattle herd and by nitrate-based fertilisers are only slowly being tackled. Ireland’s transport sector is also a big polluter.

Last year Ireland’s Supreme Court, the country’s highest judicial authority, described the Dublin government’s climate policies as “excessively vague and aspirational” and lacking in clear plans and goals. − Climate News Network

Ancient sea level rises may have been fairly minimal

Maybe ancient sea level rises were not so dramatic. But they’d still have been pretty frightening.

LONDON, 12 August, 2021 − Earth scientists have measured the rising tides of a warmer world more than 100 millennia ago and found a glimmer of good news: ancient sea level rises during a warm spell in the last Ice Age were quite possibly only about 1.2 metres higher than they are today.

Since, between 128,000 and 117,000 years ago, the world was perhaps as much as 2°C warmer than it would become for most of human history, this really is encouraging. Right now, climate scientists project a rise of somewhere between 60cm and 1.5m later this century, as global temperature levels rise 2°C or more above those normal before the Industrial Revolution.

But until now, geological orthodoxy has proposed that during the last “interglacial” or sudden warming, sea levels rose by six metres or possibly even nine metres. This could only happen if the Antarctic or Greenland ice sheets had collapsed.

And although these are indeed already losing ice at an accelerating rate, it doesn’t seem possible for such a colossal quantity of ice to melt in only a handful of decades.

Missing factor

So there was a mismatch between the predictions of the world’s scientists and the apparent evidence from the past.

Now a new study in the Proceedings of the National Academy of Sciences offers a solution: calculations about past sea level heights may have been perhaps too gloomy because they did not fully factor in sea level’s other great uncertainty — the movement of the continents lapped by the sea.

This bedevils all predictions about sea level rise. Seas rise and fall with global temperatures, but so do landmasses. Right now, although sea level is creeping up at a rate measured in millimetres per year, the land under a number of great coastal cities is sinking dramatically, as humans build  ever more massive cities and abstract ever more groundwater. So predictions warn that millions could be at risk of coastal flooding.

But there is another, deeper reason for the uncertainty: as rising temperatures remove the massive burden of ice from glaciated land, and wind and rain erode mountains, so the subterranean rocks in the Earth’s mantle, far below the crust, respond by inching upwards. Even the seemingly solid rocks are elastic, subsiding under pressure and rising when the mass is removed.

“Models of ice sheets are still in their toddlerhood”

All this means that, unless researchers can make an accurate estimate of land movement as well, sea level estimates are riven with uncertainties.

So a team from Columbia University in the US has looked at evidence of sea level rise and fall preserved in fossilised reefs and dunes in just one 1200km chain of islands − the Bahamas in the Atlantic − to come up with a new set of projections.

In the next 100 years, sea levels will rise by about 1.2 metres. This could be too modest: sea levels could just possibly rise by perhaps 5.3 metres, but this doesn’t seem likely. And a nine-metre rise is highly improbable.

“To get to nine metres of sea level rise, you’d have to melt large parts of Greenland and Antarctica,” said Blake Dyer, of the university’s Lamont-Doherty Earth Observatory.

Tricky calculation

“This suggests that didn’t happen. So maybe we should feel not so bad about the future. On the other hand, our lower estimate is bad, and our upper one is really bad.”

At the heart of the puzzle is a phenomenon known to geophysicists as isostasy: vast tracts of continental landmass have been heaving up and down, imperceptibly, over periods of tens of thousands of years, in response to ice and erosion.

So calculating sea level rise and fall when the thing on which sea level measurements are recorded − the land − is itself always shifting becomes tricky. That has always been why climate projections of sea levels contain a range of forecasts, rather than a hard number.

The argument is that changes recorded along the north-south lie of the Bahamas would provide a new and more sophisticated way of reconstructing sea heights in the relatively recent past.

Melting not guaranteed

The study doesn’t settle the question: estimates of past sea level change on a dramatic scale come from many parts of the planet, and glaciologists still have to reconstruct the rate at which the northern ice, for instance, may have retreated while the southern ice cap continued to advance during the last interglacial: that too would have limited sea level rise.

“This is still a question. Models of ice sheets are still in their toddlerhood,” said Maureen Raymo, director of the Earth Observatory and a co-author.

Human carbon emissions are now heating the globe far more rapidly and evenly than during the last interglacial, so there is no guarantee of any melting at different rates in two hemispheres

“That makes it more difficult to apply the results to today. The easy thing to say would be, ‘Oh we showed that sea levels were not so bad, and that’s terrific.’  The harder answer, the more honest answer, is that maybe things were different then, and we’re not in the clear.” − Climate News Network

Maybe ancient sea level rises were not so dramatic. But they’d still have been pretty frightening.

LONDON, 12 August, 2021 − Earth scientists have measured the rising tides of a warmer world more than 100 millennia ago and found a glimmer of good news: ancient sea level rises during a warm spell in the last Ice Age were quite possibly only about 1.2 metres higher than they are today.

Since, between 128,000 and 117,000 years ago, the world was perhaps as much as 2°C warmer than it would become for most of human history, this really is encouraging. Right now, climate scientists project a rise of somewhere between 60cm and 1.5m later this century, as global temperature levels rise 2°C or more above those normal before the Industrial Revolution.

But until now, geological orthodoxy has proposed that during the last “interglacial” or sudden warming, sea levels rose by six metres or possibly even nine metres. This could only happen if the Antarctic or Greenland ice sheets had collapsed.

And although these are indeed already losing ice at an accelerating rate, it doesn’t seem possible for such a colossal quantity of ice to melt in only a handful of decades.

Missing factor

So there was a mismatch between the predictions of the world’s scientists and the apparent evidence from the past.

Now a new study in the Proceedings of the National Academy of Sciences offers a solution: calculations about past sea level heights may have been perhaps too gloomy because they did not fully factor in sea level’s other great uncertainty — the movement of the continents lapped by the sea.

This bedevils all predictions about sea level rise. Seas rise and fall with global temperatures, but so do landmasses. Right now, although sea level is creeping up at a rate measured in millimetres per year, the land under a number of great coastal cities is sinking dramatically, as humans build  ever more massive cities and abstract ever more groundwater. So predictions warn that millions could be at risk of coastal flooding.

But there is another, deeper reason for the uncertainty: as rising temperatures remove the massive burden of ice from glaciated land, and wind and rain erode mountains, so the subterranean rocks in the Earth’s mantle, far below the crust, respond by inching upwards. Even the seemingly solid rocks are elastic, subsiding under pressure and rising when the mass is removed.

“Models of ice sheets are still in their toddlerhood”

All this means that, unless researchers can make an accurate estimate of land movement as well, sea level estimates are riven with uncertainties.

So a team from Columbia University in the US has looked at evidence of sea level rise and fall preserved in fossilised reefs and dunes in just one 1200km chain of islands − the Bahamas in the Atlantic − to come up with a new set of projections.

In the next 100 years, sea levels will rise by about 1.2 metres. This could be too modest: sea levels could just possibly rise by perhaps 5.3 metres, but this doesn’t seem likely. And a nine-metre rise is highly improbable.

“To get to nine metres of sea level rise, you’d have to melt large parts of Greenland and Antarctica,” said Blake Dyer, of the university’s Lamont-Doherty Earth Observatory.

Tricky calculation

“This suggests that didn’t happen. So maybe we should feel not so bad about the future. On the other hand, our lower estimate is bad, and our upper one is really bad.”

At the heart of the puzzle is a phenomenon known to geophysicists as isostasy: vast tracts of continental landmass have been heaving up and down, imperceptibly, over periods of tens of thousands of years, in response to ice and erosion.

So calculating sea level rise and fall when the thing on which sea level measurements are recorded − the land − is itself always shifting becomes tricky. That has always been why climate projections of sea levels contain a range of forecasts, rather than a hard number.

The argument is that changes recorded along the north-south lie of the Bahamas would provide a new and more sophisticated way of reconstructing sea heights in the relatively recent past.

Melting not guaranteed

The study doesn’t settle the question: estimates of past sea level change on a dramatic scale come from many parts of the planet, and glaciologists still have to reconstruct the rate at which the northern ice, for instance, may have retreated while the southern ice cap continued to advance during the last interglacial: that too would have limited sea level rise.

“This is still a question. Models of ice sheets are still in their toddlerhood,” said Maureen Raymo, director of the Earth Observatory and a co-author.

Human carbon emissions are now heating the globe far more rapidly and evenly than during the last interglacial, so there is no guarantee of any melting at different rates in two hemispheres

“That makes it more difficult to apply the results to today. The easy thing to say would be, ‘Oh we showed that sea levels were not so bad, and that’s terrific.’  The harder answer, the more honest answer, is that maybe things were different then, and we’re not in the clear.” − Climate News Network

Climate heat’s tides may rise above safety levels

Millions will either have to flee from climate heat’s tides, or find new ways to stay above water.

LONDON, 21 June, 2021 − If global heating is not to be stopped − which seems the case − then governments, civil authorities and communities must start thinking of ways to live with it, including how to survive climate heat’s tides.

That could mean building floating cities that will bob up and down with the tides, or existing cities in which the streets have become canals and the parks have become lakes. It will also mean, as land is surrendered to the sea, that cities will have to become more compact, and more crowded, on higher ground.

It could also mean urban forests and vertical forests: skyscrapers with balcony gardens, orchards and micro-wildernesses all the way up. It could mean that farms convert to aquaculture: where saltmarsh lamb once grazed, farmers might raise shrimps and shellfish.

This is called managed retreat. As the polar icecaps melt, temperature extremes rise, droughts multiply and floods and superstorms become ever more intense, humans will have to adapt.

“Climate change is affecting people all over the world. One potential strategy, moving away from hazards, could be very effective, but it often gets overlooked”

By 2100, at the most conservative estimate, around 88 million people could be forced to relocate, as the high tides get ever higher, and the seas begin to erode or invade the world’s coasts. At the most alarming estimate, the numbers of displaced persons could rise to 1.4 billion.

“Climate change is affecting people all over the world, and everyone is trying to figure out what to do about it. One potential strategy, moving away from hazards, could be very effective, but it often gets overlooked,” said A R Siders, of the Disaster Research Center at the University of Delaware in the US.

“We are looking at the different ways society can dream bigger when planning for climate change and how community values and priorities play a role in that.”

She and a colleague argue in the journal Science that in a small way managed retreat has already begun: in the US some 45,000 families have been helped to move out of flood-prone housing in the last 30 years, and “this represents a tiny fraction of the millions at risk and is fewer than the number of homes experiencing repeated damage and the number of new homes built in floodplains.”

The point is that much climate thinking is still short-term. “It’s hard to make decisions about climate change if we are thinking 5-10 years out. We are building infrastructure that lasts 50-100 years; our planning should be equally long,” Dr Siders said.

Living with risk

The researchers list the challenges ahead: communities that live near the wild lands must learn to live with the increasing threat of forest fires; city dwellers in the warmer climates could have to face potentially lethal extremes of heat; low-lying island nations in the Pacific may have to transfer whole populations to other countries.

Some low-lying coastal cities have already begun to adapt: Rotterdam in the Netherlands already has floating homes in Nassau Harbour that rise and fall with the tides. New York City, hard hit by Superstorm Sandy in 2012, is contemplating a floodwall in its East River.

Flooding on the US Atlantic coasts is expected to get worse: millions of Americans will probably have to migrate inland or become climate refugees. Dr Siders and colleagues began urging strategies of what she calls planned retreat two years ago.

At least one US Atlantic settlement could be be swept away or inundated by mid-century. For the people of Delaware, the problems are immediate.
“Communities, towns and cities are making decisions now that affect the future,” Dr Siders said.

“Locally, Delaware is building faster inside the floodplain than out of it. We are making plans for beach nourishment and where to build sea walls. We’re making these decisions now, so we should be considering all the options on the table, not just the ones that keep people in place.” − Climate News Network.

Millions will either have to flee from climate heat’s tides, or find new ways to stay above water.

LONDON, 21 June, 2021 − If global heating is not to be stopped − which seems the case − then governments, civil authorities and communities must start thinking of ways to live with it, including how to survive climate heat’s tides.

That could mean building floating cities that will bob up and down with the tides, or existing cities in which the streets have become canals and the parks have become lakes. It will also mean, as land is surrendered to the sea, that cities will have to become more compact, and more crowded, on higher ground.

It could also mean urban forests and vertical forests: skyscrapers with balcony gardens, orchards and micro-wildernesses all the way up. It could mean that farms convert to aquaculture: where saltmarsh lamb once grazed, farmers might raise shrimps and shellfish.

This is called managed retreat. As the polar icecaps melt, temperature extremes rise, droughts multiply and floods and superstorms become ever more intense, humans will have to adapt.

“Climate change is affecting people all over the world. One potential strategy, moving away from hazards, could be very effective, but it often gets overlooked”

By 2100, at the most conservative estimate, around 88 million people could be forced to relocate, as the high tides get ever higher, and the seas begin to erode or invade the world’s coasts. At the most alarming estimate, the numbers of displaced persons could rise to 1.4 billion.

“Climate change is affecting people all over the world, and everyone is trying to figure out what to do about it. One potential strategy, moving away from hazards, could be very effective, but it often gets overlooked,” said A R Siders, of the Disaster Research Center at the University of Delaware in the US.

“We are looking at the different ways society can dream bigger when planning for climate change and how community values and priorities play a role in that.”

She and a colleague argue in the journal Science that in a small way managed retreat has already begun: in the US some 45,000 families have been helped to move out of flood-prone housing in the last 30 years, and “this represents a tiny fraction of the millions at risk and is fewer than the number of homes experiencing repeated damage and the number of new homes built in floodplains.”

The point is that much climate thinking is still short-term. “It’s hard to make decisions about climate change if we are thinking 5-10 years out. We are building infrastructure that lasts 50-100 years; our planning should be equally long,” Dr Siders said.

Living with risk

The researchers list the challenges ahead: communities that live near the wild lands must learn to live with the increasing threat of forest fires; city dwellers in the warmer climates could have to face potentially lethal extremes of heat; low-lying island nations in the Pacific may have to transfer whole populations to other countries.

Some low-lying coastal cities have already begun to adapt: Rotterdam in the Netherlands already has floating homes in Nassau Harbour that rise and fall with the tides. New York City, hard hit by Superstorm Sandy in 2012, is contemplating a floodwall in its East River.

Flooding on the US Atlantic coasts is expected to get worse: millions of Americans will probably have to migrate inland or become climate refugees. Dr Siders and colleagues began urging strategies of what she calls planned retreat two years ago.

At least one US Atlantic settlement could be be swept away or inundated by mid-century. For the people of Delaware, the problems are immediate.
“Communities, towns and cities are making decisions now that affect the future,” Dr Siders said.

“Locally, Delaware is building faster inside the floodplain than out of it. We are making plans for beach nourishment and where to build sea walls. We’re making these decisions now, so we should be considering all the options on the table, not just the ones that keep people in place.” − Climate News Network.

The very expensive human cost of climate change

Storms devastate. Climate change makes them more devastating. Now we know how much the human cost of climate change really is.

LONDON, 25 May, 2021 − We know already that the human cost of climate change is immense. Now we can put a figure on it. Nine years on, New Yorkers have a clearer idea of the direct cost of human-driven climate change to them during just one stormy weekend in October 2012.

They became poorer by $8.1 billion, say researchers from Princeton, New Brunswick and Hoboken in New Jersey, and Boston in Massachusetts, just because of sea level rise powered first by global heating fuelled by profligate combustion worldwide of coal, oil and gas, and then by a superstorm called Hurricane Sandy.

Researchers can also number the additional people who suffered damages inflicted precisely because of human-driven climate change on that one long, painful weekend: 71,000.

“This study is the first to isolate the human-contributed sea level effects during a coastal storm and put a dollar sign to the additional flooding damage,” said Philip Orton, of Stevens Institute of Technology in Hoboken, one of the authors.

“With coastal flooding increasingly impacting communities and causing widespread destruction, pinpointing the financial toll and lives affected by climate change will hopefully add urgency to our efforts to reduce it.”

“If we were to calculate the cost of climate change across all flooding events that figure would provide clarity on the severe damage we are inflicting on our planet”

There would have been damage anyway: Sandy was a powerful hurricane that slammed into the northeast US coast so hard it set the earthquake alarms ringing. The destruction attributed to Sandy is more than $62 billion, as one of the worst storms in history at the New York bight arrived with the evening high tide to cause devastation and disruption in New York City, New Jersey and Connecticut.

It also killed 43 people in New York City and destroyed thousands of homes and around a quarter of a million cars, vans, buses and trucks.

And now a study in the journal Nature Communications reasons that anthropogenic or human-powered sea level rise must have accounted for at least 13% of the total bill. That is because global heating from greenhouse gas emissions seems to have raised mean sea levels in the New York region by around 10 cms over the last century or so. In fact, Sandy arrived with the highest water level in at least 300 years in the New York metropolitan area.

The researchers set themselves the target of identifying precisely the impact of climate change on sea level rise in that region. To do that, they had to subtract the change that could be explained by coastal subsidence: as a consequence of heavy construction and groundwater abstraction, coastal settlements everywhere are likely to subside.

Knowing the threat

Then they combed maps of the damage, contour data and insurance data to arrive at a specific contribution by sea level rise linked to climate change: at the very least, they judged, $4.7bn, at the most $14bn, and so they compromised on $8bn.

They then numbered the humans who might not have been hit by flooding had there been no climate change: they calculated at least 40,000, and no more than 131,000, before settling on 70,000 additional victims.

Such exercises matter: city planners, coastal defence agencies, insurers and seaside property-holders need to know the scale of extra risk conferred by climate change. There will be more storm damage and flooding, and the new methodology could be adapted to other vulnerable cities.

US coasts already face more frequent floods, rising seas promise more such superstorms and − once again because of global heating − the north-eastern US seaboard can expect to be in the track of fiercer hurricanes.

“If we were to calculate the cost of climate change across all flooding events − both nuisance floods and those caused by extreme storm events − that figure would be enormous,” Dr Orton said. ”It would provide clarity on the severe damage we are inflicting on ourselves and on our planet.” − Climate News Network

Storms devastate. Climate change makes them more devastating. Now we know how much the human cost of climate change really is.

LONDON, 25 May, 2021 − We know already that the human cost of climate change is immense. Now we can put a figure on it. Nine years on, New Yorkers have a clearer idea of the direct cost of human-driven climate change to them during just one stormy weekend in October 2012.

They became poorer by $8.1 billion, say researchers from Princeton, New Brunswick and Hoboken in New Jersey, and Boston in Massachusetts, just because of sea level rise powered first by global heating fuelled by profligate combustion worldwide of coal, oil and gas, and then by a superstorm called Hurricane Sandy.

Researchers can also number the additional people who suffered damages inflicted precisely because of human-driven climate change on that one long, painful weekend: 71,000.

“This study is the first to isolate the human-contributed sea level effects during a coastal storm and put a dollar sign to the additional flooding damage,” said Philip Orton, of Stevens Institute of Technology in Hoboken, one of the authors.

“With coastal flooding increasingly impacting communities and causing widespread destruction, pinpointing the financial toll and lives affected by climate change will hopefully add urgency to our efforts to reduce it.”

“If we were to calculate the cost of climate change across all flooding events that figure would provide clarity on the severe damage we are inflicting on our planet”

There would have been damage anyway: Sandy was a powerful hurricane that slammed into the northeast US coast so hard it set the earthquake alarms ringing. The destruction attributed to Sandy is more than $62 billion, as one of the worst storms in history at the New York bight arrived with the evening high tide to cause devastation and disruption in New York City, New Jersey and Connecticut.

It also killed 43 people in New York City and destroyed thousands of homes and around a quarter of a million cars, vans, buses and trucks.

And now a study in the journal Nature Communications reasons that anthropogenic or human-powered sea level rise must have accounted for at least 13% of the total bill. That is because global heating from greenhouse gas emissions seems to have raised mean sea levels in the New York region by around 10 cms over the last century or so. In fact, Sandy arrived with the highest water level in at least 300 years in the New York metropolitan area.

The researchers set themselves the target of identifying precisely the impact of climate change on sea level rise in that region. To do that, they had to subtract the change that could be explained by coastal subsidence: as a consequence of heavy construction and groundwater abstraction, coastal settlements everywhere are likely to subside.

Knowing the threat

Then they combed maps of the damage, contour data and insurance data to arrive at a specific contribution by sea level rise linked to climate change: at the very least, they judged, $4.7bn, at the most $14bn, and so they compromised on $8bn.

They then numbered the humans who might not have been hit by flooding had there been no climate change: they calculated at least 40,000, and no more than 131,000, before settling on 70,000 additional victims.

Such exercises matter: city planners, coastal defence agencies, insurers and seaside property-holders need to know the scale of extra risk conferred by climate change. There will be more storm damage and flooding, and the new methodology could be adapted to other vulnerable cities.

US coasts already face more frequent floods, rising seas promise more such superstorms and − once again because of global heating − the north-eastern US seaboard can expect to be in the track of fiercer hurricanes.

“If we were to calculate the cost of climate change across all flooding events − both nuisance floods and those caused by extreme storm events − that figure would be enormous,” Dr Orton said. ”It would provide clarity on the severe damage we are inflicting on ourselves and on our planet.” − Climate News Network

Faster Greenland ice melt could be unstoppable

A rapid thaw could destroy a whole ice sheet if the faster Greenland ice melt scientists have found spreads across the island.

LONDON, 24 May, 2021 − Researchers say the faster Greenland ice melt affecting part of the island could mean a large area is on the verge of irreversible loss. Their new study shows that the central western region of the ice sheet is near what climate scientists call “a tipping point.”

That is, once the ice starts to slide away, most of it will tip into the sea, to raise global sea levels and potentially to trigger the collapse of the great Atlantic Ocean current that enhances the climate of north-west Europe.

“We have found evidence that the central western part of the Greenland ice sheet has been destabilising and is now close to a critical transition,” said Niklas Boers, of the Potsdam Institute for Climate Impact Research. “Our results suggest there will be substantially enhanced melting in the future − which is quite worrying.”

Dr Boers and his colleague Martin Rypdal of the Arctic University of Norway report in the Proceedings of the National Academy of Sciences that they looked at data since 1880 of melt rates and ice-sheet altitude shifts of a region called the Jakobshavn basin in the central western region of the northern hemisphere’s biggest single block of ice − a block big enough to raise global sea levels by seven metres, were it all to melt.

And what they saw was something alarming: evidence that surface melting is beginning to accelerate. The conclusion, for now, is tentative.

“It’s high time we dramatically and substantially reduce greenhouse gas emissions from burning fossil fuels”

“We might be seeing the beginning of a large scale destabilisation, but at the moment we cannot tell, unfortunately,” Dr Boers said. “So far the signals we see are only regional, but that might simply be due to the scarcity of accurate and long-term data for other parts of the ice sheet.”

The region is home to the Jakobshavn glacier, which began to accelerate its flow to the sea this century, but the alarm is consistent with other studies of the mass of ice piled up on Greenland.

For most of the last 10,000 years or so, the summer loss of ice through melt and glacial flow has been replaced by winter snow. But in recent years, other research teams have warned, repeatedly, that the rate of  melting of Greenland’s surface ice has increased, in ways that really could threaten the stability of the entire sheet. Last year, ice loss reached a new record.

Greenland’s ice sheet is high: colder, therefore, at altitude. As the surface melts, the elevation becomes lower, and therefore increasingly warmer. So once the high ground surface begins to melt away, it could reach a level below which there is no obvious reason why the process should stop.

Climate computer simulations predict a threshold of global average temperature change that could, in effect, start a process in which the loss of the entire ice sheet would become inevitable. The loss would happen over hundreds of years, or perhaps thousands, but once begun it would continue inexorably.

Extreme Arctic warming

Global sea levels would rise at ever faster rates, and the arrival of so much fresh water in the north Atlantic would be enough to interfere with the ocean circulation.

For years oceanographers have been warning that the existing current, which takes warm tropical water as far north as the Arctic, could weaken, or fail, with unpredictable and uncomfortable consequences for north European nations.

The only way to stop Greenland’s accelerated melt, once it reaches a critical point, would be to lower the temperature of the whole planet back to that which was normal more than 200 years ago. That is unlikely to happen. Instead, for the moment, the evidence is that average temperatures worldwide could rise by 3°C or more by 2100. The Arctic, however, is likely to become much, much warmer.

“So practically, the current and near-future mass loss will be irreversible,” said Dr Boers, “That’s why it’s high time we dramatically and substantially reduce greenhouse gas emissions from burning fossil fuels and restabilise the ice sheet and our climate.” − Climate News Network

A rapid thaw could destroy a whole ice sheet if the faster Greenland ice melt scientists have found spreads across the island.

LONDON, 24 May, 2021 − Researchers say the faster Greenland ice melt affecting part of the island could mean a large area is on the verge of irreversible loss. Their new study shows that the central western region of the ice sheet is near what climate scientists call “a tipping point.”

That is, once the ice starts to slide away, most of it will tip into the sea, to raise global sea levels and potentially to trigger the collapse of the great Atlantic Ocean current that enhances the climate of north-west Europe.

“We have found evidence that the central western part of the Greenland ice sheet has been destabilising and is now close to a critical transition,” said Niklas Boers, of the Potsdam Institute for Climate Impact Research. “Our results suggest there will be substantially enhanced melting in the future − which is quite worrying.”

Dr Boers and his colleague Martin Rypdal of the Arctic University of Norway report in the Proceedings of the National Academy of Sciences that they looked at data since 1880 of melt rates and ice-sheet altitude shifts of a region called the Jakobshavn basin in the central western region of the northern hemisphere’s biggest single block of ice − a block big enough to raise global sea levels by seven metres, were it all to melt.

And what they saw was something alarming: evidence that surface melting is beginning to accelerate. The conclusion, for now, is tentative.

“It’s high time we dramatically and substantially reduce greenhouse gas emissions from burning fossil fuels”

“We might be seeing the beginning of a large scale destabilisation, but at the moment we cannot tell, unfortunately,” Dr Boers said. “So far the signals we see are only regional, but that might simply be due to the scarcity of accurate and long-term data for other parts of the ice sheet.”

The region is home to the Jakobshavn glacier, which began to accelerate its flow to the sea this century, but the alarm is consistent with other studies of the mass of ice piled up on Greenland.

For most of the last 10,000 years or so, the summer loss of ice through melt and glacial flow has been replaced by winter snow. But in recent years, other research teams have warned, repeatedly, that the rate of  melting of Greenland’s surface ice has increased, in ways that really could threaten the stability of the entire sheet. Last year, ice loss reached a new record.

Greenland’s ice sheet is high: colder, therefore, at altitude. As the surface melts, the elevation becomes lower, and therefore increasingly warmer. So once the high ground surface begins to melt away, it could reach a level below which there is no obvious reason why the process should stop.

Climate computer simulations predict a threshold of global average temperature change that could, in effect, start a process in which the loss of the entire ice sheet would become inevitable. The loss would happen over hundreds of years, or perhaps thousands, but once begun it would continue inexorably.

Extreme Arctic warming

Global sea levels would rise at ever faster rates, and the arrival of so much fresh water in the north Atlantic would be enough to interfere with the ocean circulation.

For years oceanographers have been warning that the existing current, which takes warm tropical water as far north as the Arctic, could weaken, or fail, with unpredictable and uncomfortable consequences for north European nations.

The only way to stop Greenland’s accelerated melt, once it reaches a critical point, would be to lower the temperature of the whole planet back to that which was normal more than 200 years ago. That is unlikely to happen. Instead, for the moment, the evidence is that average temperatures worldwide could rise by 3°C or more by 2100. The Arctic, however, is likely to become much, much warmer.

“So practically, the current and near-future mass loss will be irreversible,” said Dr Boers, “That’s why it’s high time we dramatically and substantially reduce greenhouse gas emissions from burning fossil fuels and restabilise the ice sheet and our climate.” − Climate News Network

Tide of climate refugees swells as Earth heats up

Prepare for the arrival of more displaced persons, climate refugees driven from their homes by global heating.

LONDON, 11 May, 2021 − Natural hazards − most of them driven by climate change − have forced an estimated 288 million people from their homes since 2008. That is three times the numbers displaced by war and conflict. These people have become, however briefly, climate refugees.

And the number will grow. A new study has found that for every 1°C rise in global average temperatures, the chance of displacement from river flooding alone will rise by 50%. And that calculation is based on population numbers right now. As human numbers rise, so will the risk − by 110%.

Another study makes an even more precise prediction: thanks to rising sea levels and more intense cyclonic storms, an estimated 1.3 million people in Bangladesh will be forced into migration by 2050. Many will move further inland − but many are likely to be forced across national borders, to trigger more displacement.

Drought and famine are climate-related natural disasters. So are forest fires, extreme heat waves, catastrophic windstorms and devastating floods, driven either by torrential rainfall or rising sea levels, or both.

Climate scientists, environmentalists and geographers have been warning for years that the numbers of people driven from their homes by climate change is on the increase: even in the US, as many as 13 million people could be forced from their coastal settlements by sea level rise.

“It is imperative that we have a better understanding of how the risks are changing”

Swiss scientists report in the journal Environmental Research Letters that even if the world keeps to an agreement to limit global warming to no more than 2°C, because the global population is rising, the average risk of displacement by river flooding is likely to rise by 110% by the end of the century.

If however nations take no drastic action, and go on burning ever more fossil fuels, the global average risk of being forced from home by swirling waters could rise by up to 350%.

“Because floods are a major driver of displacement, and due to the fact that they are influenced by climate change, it is imperative that we have a better understanding of how the risks are changing,” said Pui Man Kam of the Swiss Federal Institute of Technology, known as ETH Zurich, who led the study.

An estimated 680 million people worldwide live in low-lying coastal zones. Spanish, Italian and US scientists report in the journal Earth’s Future that they had developed a data model to predict the numbers likely to be displaced by any natural hazard to become climate refugees.

They tested it in the context of sea level rise, storms and floods in one low-lying country laced with rivers: Bangladesh. It is home to 163 million people, of whom 41% live at elevations lower than 10 metres above sea level.

Countrywide unrest likely

Their research found that although people in the coastal districts along the Bay of Bengal would be flooded, a surge of migration would ripple across the landscape and impact all 64 districts, including the capital, Dhaka.

Thanks to climate migration, numbers in the city should grow and eventually decline, as people moved to get away from the new arrivals. That is, flood events at the coast could ultimately trigger human unrest in the entire country.
“Droughts, desertification, floods, earthquakes, and wildfire threaten livelihoods worldwide; from wealthy to developing economies, every country is vulnerable to environmental change,” said Maurizio Porfiri of New York University’s Tandon School of Engineering.

“Mathematical models can assist in providing reliable predictions of environmental migration, which are critical for devising effective policy initiatives and improving our preparedness for future migration patterns.” − Climate News Network

Prepare for the arrival of more displaced persons, climate refugees driven from their homes by global heating.

LONDON, 11 May, 2021 − Natural hazards − most of them driven by climate change − have forced an estimated 288 million people from their homes since 2008. That is three times the numbers displaced by war and conflict. These people have become, however briefly, climate refugees.

And the number will grow. A new study has found that for every 1°C rise in global average temperatures, the chance of displacement from river flooding alone will rise by 50%. And that calculation is based on population numbers right now. As human numbers rise, so will the risk − by 110%.

Another study makes an even more precise prediction: thanks to rising sea levels and more intense cyclonic storms, an estimated 1.3 million people in Bangladesh will be forced into migration by 2050. Many will move further inland − but many are likely to be forced across national borders, to trigger more displacement.

Drought and famine are climate-related natural disasters. So are forest fires, extreme heat waves, catastrophic windstorms and devastating floods, driven either by torrential rainfall or rising sea levels, or both.

Climate scientists, environmentalists and geographers have been warning for years that the numbers of people driven from their homes by climate change is on the increase: even in the US, as many as 13 million people could be forced from their coastal settlements by sea level rise.

“It is imperative that we have a better understanding of how the risks are changing”

Swiss scientists report in the journal Environmental Research Letters that even if the world keeps to an agreement to limit global warming to no more than 2°C, because the global population is rising, the average risk of displacement by river flooding is likely to rise by 110% by the end of the century.

If however nations take no drastic action, and go on burning ever more fossil fuels, the global average risk of being forced from home by swirling waters could rise by up to 350%.

“Because floods are a major driver of displacement, and due to the fact that they are influenced by climate change, it is imperative that we have a better understanding of how the risks are changing,” said Pui Man Kam of the Swiss Federal Institute of Technology, known as ETH Zurich, who led the study.

An estimated 680 million people worldwide live in low-lying coastal zones. Spanish, Italian and US scientists report in the journal Earth’s Future that they had developed a data model to predict the numbers likely to be displaced by any natural hazard to become climate refugees.

They tested it in the context of sea level rise, storms and floods in one low-lying country laced with rivers: Bangladesh. It is home to 163 million people, of whom 41% live at elevations lower than 10 metres above sea level.

Countrywide unrest likely

Their research found that although people in the coastal districts along the Bay of Bengal would be flooded, a surge of migration would ripple across the landscape and impact all 64 districts, including the capital, Dhaka.

Thanks to climate migration, numbers in the city should grow and eventually decline, as people moved to get away from the new arrivals. That is, flood events at the coast could ultimately trigger human unrest in the entire country.
“Droughts, desertification, floods, earthquakes, and wildfire threaten livelihoods worldwide; from wealthy to developing economies, every country is vulnerable to environmental change,” said Maurizio Porfiri of New York University’s Tandon School of Engineering.

“Mathematical models can assist in providing reliable predictions of environmental migration, which are critical for devising effective policy initiatives and improving our preparedness for future migration patterns.” − Climate News Network

2°C more heat may mean catastrophic sea level rise

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

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

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

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

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

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

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

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

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

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

On course for 3°C

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

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

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

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

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

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

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

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

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

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

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

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

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

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

On course for 3°C

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

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

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

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

Faster glacier melting raises hunger threat

The world’s upland icecaps are in retreat. Faster glacier melting could slow to a trickle streams that once fed foaming rivers.

LONDON, 5 May, 2021 − Glacial retreat − the rate at which mountain ice is turning to running water − has accelerated. In the last two decades, the world’s 220,000 glaciers have lost ice at the rate of 267 billion tonnes a year on average, and this faster glacier melting could soon imperil downstream food and water supplies.

To make sense of this almost unimaginable volume, think of a country the size of Switzerland. And then submerge it six metres deep in water. And then go on doing that every year for 20 years.

European scientists report in the journal Nature that, on the basis of satellite data, they assembled a global snapshot of the entire world’s stock of land-borne ice, excluding Antarctica and Greenland. And then they began to measure the impact of global heating driven by profligate fossil fuel use on the lofty, frozen beauty of the Alps, the Hindu Kush, the Andes, the Himalayas and the mountains of Alaska.

They found not just loss, but a loss that was accelerating sharply. Between 2000 and 2004, the glaciers together surrendered 227 billion tons of ice a year on average. By 2015 to 2019, the annual loss had risen to 298 billion tonnes. The run-off from the retreating glaciers alone caused more than one-fifth of observed sea level rise this century.

“The world really needs to act now to prevent the worst case climate change scenario”

Right now an estimated 200 million people live on land that is likely to be flooded by high tides at the close of this century. Altogether, one billion people could face water shortages and failed harvests within the next three decades, in many instances because of glacier loss.

Glacial ice in the high mountains represents so much water stored, to be released in the summer melt to nourish crops downstream. The fastest melt is in Alaska, Iceland and the Alps, but global warming is also affecting the Pamirs, the Hindu Kush and other peaks in Central Asia.

“The situation in the Himalayas is particularly worrying,” said Romain Hugonnet, of the Swiss Federal Institute of Technology, known as ETH Zurich, and the University of Toulouse.

“During the dry season, glacial meltwater is an important source that feeds major waterways such as the Ganges, Brahmaputra and Indus rivers. Right now, this increased melting acts as a buffer for people living in the region, but if Himalayan glacier shrinkage keeps accelerating, populous countries like India and Bangladesh could face food and water shortages in a few decades.”

Climate change link

Such news could hardly be a shock to geographers and climate scientists: researchers have been warning for years that as many as half of the planet’s mountain glaciers could be gone by the century’s end. Europe’s Alps could by 2100 have lost nine-tenths of all the continent’s flowing ice.

Researchers have also identified the consequent risk to water supplies for millions, and confirmed an “irrefutable” link between human-induced climate change and glacier loss. So the latest research is an update, and a check on subtle changes in rates of loss, based on imagery from Nasa’s Terra satellite, which has been orbiting the planet every 100 minutes since 1999.

The scientists found that melt rates in Greenland, Iceland and Scandinavia all slowed in the first two decades of the century, perhaps because of a change in temperatures and precipitation in the North Atlantic. Conversely, glaciers in the Karakoram range that had once seemed anomalously stable had now started to melt.

“Our findings are important on a political level,” said Daniel Farinotti, also of ETH Zurich. “The world really needs to act now to prevent the worst case climate change scenario.” − Climate News Network

The world’s upland icecaps are in retreat. Faster glacier melting could slow to a trickle streams that once fed foaming rivers.

LONDON, 5 May, 2021 − Glacial retreat − the rate at which mountain ice is turning to running water − has accelerated. In the last two decades, the world’s 220,000 glaciers have lost ice at the rate of 267 billion tonnes a year on average, and this faster glacier melting could soon imperil downstream food and water supplies.

To make sense of this almost unimaginable volume, think of a country the size of Switzerland. And then submerge it six metres deep in water. And then go on doing that every year for 20 years.

European scientists report in the journal Nature that, on the basis of satellite data, they assembled a global snapshot of the entire world’s stock of land-borne ice, excluding Antarctica and Greenland. And then they began to measure the impact of global heating driven by profligate fossil fuel use on the lofty, frozen beauty of the Alps, the Hindu Kush, the Andes, the Himalayas and the mountains of Alaska.

They found not just loss, but a loss that was accelerating sharply. Between 2000 and 2004, the glaciers together surrendered 227 billion tons of ice a year on average. By 2015 to 2019, the annual loss had risen to 298 billion tonnes. The run-off from the retreating glaciers alone caused more than one-fifth of observed sea level rise this century.

“The world really needs to act now to prevent the worst case climate change scenario”

Right now an estimated 200 million people live on land that is likely to be flooded by high tides at the close of this century. Altogether, one billion people could face water shortages and failed harvests within the next three decades, in many instances because of glacier loss.

Glacial ice in the high mountains represents so much water stored, to be released in the summer melt to nourish crops downstream. The fastest melt is in Alaska, Iceland and the Alps, but global warming is also affecting the Pamirs, the Hindu Kush and other peaks in Central Asia.

“The situation in the Himalayas is particularly worrying,” said Romain Hugonnet, of the Swiss Federal Institute of Technology, known as ETH Zurich, and the University of Toulouse.

“During the dry season, glacial meltwater is an important source that feeds major waterways such as the Ganges, Brahmaputra and Indus rivers. Right now, this increased melting acts as a buffer for people living in the region, but if Himalayan glacier shrinkage keeps accelerating, populous countries like India and Bangladesh could face food and water shortages in a few decades.”

Climate change link

Such news could hardly be a shock to geographers and climate scientists: researchers have been warning for years that as many as half of the planet’s mountain glaciers could be gone by the century’s end. Europe’s Alps could by 2100 have lost nine-tenths of all the continent’s flowing ice.

Researchers have also identified the consequent risk to water supplies for millions, and confirmed an “irrefutable” link between human-induced climate change and glacier loss. So the latest research is an update, and a check on subtle changes in rates of loss, based on imagery from Nasa’s Terra satellite, which has been orbiting the planet every 100 minutes since 1999.

The scientists found that melt rates in Greenland, Iceland and Scandinavia all slowed in the first two decades of the century, perhaps because of a change in temperatures and precipitation in the North Atlantic. Conversely, glaciers in the Karakoram range that had once seemed anomalously stable had now started to melt.

“Our findings are important on a political level,” said Daniel Farinotti, also of ETH Zurich. “The world really needs to act now to prevent the worst case climate change scenario.” − Climate News Network

Climate heating may speed up to unexpected levels

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

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

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

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

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

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

Unstable at 4°C

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

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

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

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

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

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

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

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

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

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

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

Greenland’s future role

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

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

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

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

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

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

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

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

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

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

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

Unstable at 4°C

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

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

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

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

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

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

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

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

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

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

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

Greenland’s future role

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

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

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

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

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