Tag Archives: Sea levels

Rivers flood, seas rise – and land faces erosion

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

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

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

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

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

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

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

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

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

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

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

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

Erosion risk rises

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

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

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

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

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

Survival in question

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Erosion risk rises

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

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

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

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

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

Survival in question

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

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

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

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

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

Arctic heating races ahead of worst case estimates

Arctic heating is happening far faster than anybody had anticipated. And the ice record suggests this has happened before.

LONDON, 2 September, 2020 – An international team of scientists brings bad news about Arctic heating: the polar ocean is warming not only faster than anybody predicted, it is getting hotter at a rate faster than even the worst case climate scenario predictions have so far foreseen.

Such dramatic rises in Arctic temperatures have been recorded before, but only during the last Ice Age. Evidence from the Greenland ice cores suggests that temperatures rose by 10°C or even 12°C, over a period of between 40 years and a century, between 120,000 years and 11,000 years ago.

“We have been clearly underestimating the rate of temperature increases in the atmosphere nearest to the sea level, which has ultimately caused sea ice to disappear faster than we had anticipated,” said Jens Hesselbjerg Christensen, a physicist at the University of Copenhagen in Denmark, one of 16 scientists who report in the journal Nature Climate Change on a new analysis of 40 years of data from the Arctic region.

They found that, on average, the Arctic has been warming at the rate of 1°C per decade for the last four decades. Around Norway’s Svalbard archipelago, temperatures rose even faster, at 1.5°C every 10 years.

“We have been clearly underestimating the rate of temperature increases in the atmosphere nearest to the sea level, which has ultimately caused sea ice to disappear faster than we had anticipated”

During the last two centuries, as atmospheric levels of carbon dioxide climbed from an average of around 285 parts per million to more than 400ppm, so the global average temperature of the planet rose: by a fraction more than 1°C.

The latest study is a reminder that temperatures in the Arctic are rising far faster than that. And the news is hardly a shock: within the past few weeks, separate teams of researchers, reporting to other journals, have warned that Greenland – the biggest single reservoir of ice in the northern hemisphere – is melting faster than ever; more alarmingly, its icecap is losing mass at a rate that suggests the loss could become irreversible.

Researchers have also confirmed that the average planetary temperature  continues to rise inexorably, that the Arctic Ocean could be free of ice in  summer as early as 2035, and that the climate scientists’ “worst case” scenarios are no longer to be regarded as a warning of what could happen: the evidence is that what is happening now already matches the climate forecaster’s worst case. The latest finding implicitly and explicitly supports this flurry of ominous observation.

“We have looked at the climate models analysed and assessed by the UN Climate Panel,” said Professor Christensen. “Only those models based on the worst case scenario, with the highest carbon dioxide emissions, come close to what our temperature measurements show over the past 40 years, from 1979 to today.” – Climate News Network

Arctic heating is happening far faster than anybody had anticipated. And the ice record suggests this has happened before.

LONDON, 2 September, 2020 – An international team of scientists brings bad news about Arctic heating: the polar ocean is warming not only faster than anybody predicted, it is getting hotter at a rate faster than even the worst case climate scenario predictions have so far foreseen.

Such dramatic rises in Arctic temperatures have been recorded before, but only during the last Ice Age. Evidence from the Greenland ice cores suggests that temperatures rose by 10°C or even 12°C, over a period of between 40 years and a century, between 120,000 years and 11,000 years ago.

“We have been clearly underestimating the rate of temperature increases in the atmosphere nearest to the sea level, which has ultimately caused sea ice to disappear faster than we had anticipated,” said Jens Hesselbjerg Christensen, a physicist at the University of Copenhagen in Denmark, one of 16 scientists who report in the journal Nature Climate Change on a new analysis of 40 years of data from the Arctic region.

They found that, on average, the Arctic has been warming at the rate of 1°C per decade for the last four decades. Around Norway’s Svalbard archipelago, temperatures rose even faster, at 1.5°C every 10 years.

“We have been clearly underestimating the rate of temperature increases in the atmosphere nearest to the sea level, which has ultimately caused sea ice to disappear faster than we had anticipated”

During the last two centuries, as atmospheric levels of carbon dioxide climbed from an average of around 285 parts per million to more than 400ppm, so the global average temperature of the planet rose: by a fraction more than 1°C.

The latest study is a reminder that temperatures in the Arctic are rising far faster than that. And the news is hardly a shock: within the past few weeks, separate teams of researchers, reporting to other journals, have warned that Greenland – the biggest single reservoir of ice in the northern hemisphere – is melting faster than ever; more alarmingly, its icecap is losing mass at a rate that suggests the loss could become irreversible.

Researchers have also confirmed that the average planetary temperature  continues to rise inexorably, that the Arctic Ocean could be free of ice in  summer as early as 2035, and that the climate scientists’ “worst case” scenarios are no longer to be regarded as a warning of what could happen: the evidence is that what is happening now already matches the climate forecaster’s worst case. The latest finding implicitly and explicitly supports this flurry of ominous observation.

“We have looked at the climate models analysed and assessed by the UN Climate Panel,” said Professor Christensen. “Only those models based on the worst case scenario, with the highest carbon dioxide emissions, come close to what our temperature measurements show over the past 40 years, from 1979 to today.” – Climate News Network

In Arctic heat Greenland’s ice loss grows faster still

Greenland’s ice loss tipped a new record last year. This ominous milestone is just the latest in a run of alarming news.

LONDON, 24 August, 2020 – Its icecap is now smaller than at any time since measurements began: Greenland’s ice loss means it lost mass in 2019 at a record rate.

By the close of the year, thanks to high summer melt and low snowfall, the northern hemisphere’s biggest reservoir of ice had shed 532 billion tonnes into the sea – raising global sea levels by around 1.5mm in a year.

The previous record loss for Greenland was in 2012. In that year, the island lost 464 billion tonnes, according to studies of satellite data published by European scientists in the journal Communications Earth and Environment.

Greenland’s ice cap has been shrinking, if unsteadily, for many years. In 2017 and 2018, the losses continued, but only at around 100bn tonnes a year.

“After a two-year breather, the mass loss increased steeply and exceeded all annual losses since 1948, and probably for more than 100 years,” said Ingo Sasgen of the Alfred Wegener Institute in Bremerhaven, Germany, who led the study.

“There are increasingly frequent, stable high-pressure areas over the ice sheet, which promote the influx of warm air from the middle latitudes. We saw a similar pattern in the previous record year, 2012.”

“The ice sheet has lost ice every year for the past 20. If everyone’s alarm bells were not already ringing, they must be now”

He and colleagues made their calculations from data delivered by two Nasa satellites, GRACE and GRACE-FO, that measure changes in the surface gravity of the planet: a way of calculating the mass of water stored as ice, or in aquifers, and observing sea level change.

The finding is the latest in a succession of polar climate alarms. It follows closely on a warning from US scientists that ice loss from Greenland may  have reached the point of no return.

And it also follows a sober calculation of the alarming rate of planetary temperature rise in response to ever-higher use of fossil fuels that trigger ever-higher measures of greenhouse gases in the atmosphere.

And that in turn followed a warning that the entire Arctic was now warming so swiftly that the Arctic sea ice might be all but gone in the summer of 2035.

And that was only days after another research team, looking at the big picture of climate change, warned that the scenario climate forecasters liked to use as an example of their “worst case” was now a simple description of what was already happening.

“It is devastating that 2019 was another record year of ice loss. In 2012, it had been about 150 years since the ice sheet had experienced similar melt extent, and then a further 600-plus years back to find another similar event,” said Twila Moon, of the University of Colorado at Boulder, who was not involved in the research.

Damage off the scale

“We have now had record-breaking ice loss twice in less than 10 years, and the ice sheet has lost ice every year for the past 20. If everyone’s alarm bells were not already ringing, they must be now.”

The implications of continued loss of Greenland ice have been explored repeatedly: the run-off of fresh water from the ice cap to the sea is now so great that the North Atlantic is now “fresher” than at any time in the last 100 years.

And this change in water temperature and chemistry could – on the evidence of the distant past – possibly slow or switch off the circulation of the North Atlantic current, which for most of the history of human civilisation has kept the United Kingdom and north-western Europe from five to 10°C warmer than similar latitudes elsewhere.

“This tipping point in the climate system is one of the potential climate disasters facing us,” said Stuart Cunningham of the Scottish Association for Marine Science, commenting on the study.

“To transform the way we power, finance and run the world in the way we know we should is proving entirely beyond us,” said Chris Rapley, now a climate scientist at University College London, but once director of the British Antarctic Survey.

“Torpor, incompetence and indifference at the top may kill people in a health crisis, and torpedo the careers of young students in an education crisis; but the damage they are generating in the pipeline from climate change is on another scale.” – Climate News Network

Greenland’s ice loss tipped a new record last year. This ominous milestone is just the latest in a run of alarming news.

LONDON, 24 August, 2020 – Its icecap is now smaller than at any time since measurements began: Greenland’s ice loss means it lost mass in 2019 at a record rate.

By the close of the year, thanks to high summer melt and low snowfall, the northern hemisphere’s biggest reservoir of ice had shed 532 billion tonnes into the sea – raising global sea levels by around 1.5mm in a year.

The previous record loss for Greenland was in 2012. In that year, the island lost 464 billion tonnes, according to studies of satellite data published by European scientists in the journal Communications Earth and Environment.

Greenland’s ice cap has been shrinking, if unsteadily, for many years. In 2017 and 2018, the losses continued, but only at around 100bn tonnes a year.

“After a two-year breather, the mass loss increased steeply and exceeded all annual losses since 1948, and probably for more than 100 years,” said Ingo Sasgen of the Alfred Wegener Institute in Bremerhaven, Germany, who led the study.

“There are increasingly frequent, stable high-pressure areas over the ice sheet, which promote the influx of warm air from the middle latitudes. We saw a similar pattern in the previous record year, 2012.”

“The ice sheet has lost ice every year for the past 20. If everyone’s alarm bells were not already ringing, they must be now”

He and colleagues made their calculations from data delivered by two Nasa satellites, GRACE and GRACE-FO, that measure changes in the surface gravity of the planet: a way of calculating the mass of water stored as ice, or in aquifers, and observing sea level change.

The finding is the latest in a succession of polar climate alarms. It follows closely on a warning from US scientists that ice loss from Greenland may  have reached the point of no return.

And it also follows a sober calculation of the alarming rate of planetary temperature rise in response to ever-higher use of fossil fuels that trigger ever-higher measures of greenhouse gases in the atmosphere.

And that in turn followed a warning that the entire Arctic was now warming so swiftly that the Arctic sea ice might be all but gone in the summer of 2035.

And that was only days after another research team, looking at the big picture of climate change, warned that the scenario climate forecasters liked to use as an example of their “worst case” was now a simple description of what was already happening.

“It is devastating that 2019 was another record year of ice loss. In 2012, it had been about 150 years since the ice sheet had experienced similar melt extent, and then a further 600-plus years back to find another similar event,” said Twila Moon, of the University of Colorado at Boulder, who was not involved in the research.

Damage off the scale

“We have now had record-breaking ice loss twice in less than 10 years, and the ice sheet has lost ice every year for the past 20. If everyone’s alarm bells were not already ringing, they must be now.”

The implications of continued loss of Greenland ice have been explored repeatedly: the run-off of fresh water from the ice cap to the sea is now so great that the North Atlantic is now “fresher” than at any time in the last 100 years.

And this change in water temperature and chemistry could – on the evidence of the distant past – possibly slow or switch off the circulation of the North Atlantic current, which for most of the history of human civilisation has kept the United Kingdom and north-western Europe from five to 10°C warmer than similar latitudes elsewhere.

“This tipping point in the climate system is one of the potential climate disasters facing us,” said Stuart Cunningham of the Scottish Association for Marine Science, commenting on the study.

“To transform the way we power, finance and run the world in the way we know we should is proving entirely beyond us,” said Chris Rapley, now a climate scientist at University College London, but once director of the British Antarctic Survey.

“Torpor, incompetence and indifference at the top may kill people in a health crisis, and torpedo the careers of young students in an education crisis; but the damage they are generating in the pipeline from climate change is on another scale.” – Climate News Network

250 million coastal dwellers will face rising floods

Once again, researchers confirm that coastal dwellers can expect worse floods, more often and more expensively.

LONDON, 6 August, 2020 – In the next 80 years flooding around the planet’s land masses is likely to rise by almost 50%, endangering many millions of coastal dwellers.

If humans go on burning ever greater volumes of fossil fuels, while destroying ever more natural forest, then another 77 million people could be at risk of flooding, a rise of 52%.

And these floods – increasingly frequent and extending over greater areas – will put at risk cities, homes, resorts and industries valued at more than $14 trillion (£10.7tn).

This sum alone is worth 20% of global gross domestic product, the economist’s preferred indicator of economic health and wealth, according to a new study in the journal Scientific Reports.

The researchers built their argument on historic data from 681 tide-gauge stations around the world to model the growing hazard at 10,000 coastal locations.

“Compared with now, what we see as a one-in-100-year extreme flood event will be ten times more frequent because of climate change”

They conclude that the land area exposed to extreme flood will increase by more than 250,000 sq kms – an increase of 48% – to 800,000 sq kms, a threat to 252 million people.

“A warming climate is driving sea level rise because water expands as it warms, and glaciers are melting. Climate change is also increasing the frequency of extreme seas, which will further increase the risk of flooding,” said Ebru Kirezci of the University of Melbourne, Australia, who led the study.

“What the data and our model are saying is that compared with now, what we see as a one-in-100-year extreme flood event will be ten times more frequent because of climate change.”

None of this should come as a surprise to civic authorities, governments, hydraulic engineers and oceanographers: researchers have been warning for years that coastal floods driven by global heating will end up costing colossal and seemingly ever increasing sums.

On a global scale, and on regional examination, the story remains the same, and wealthy and developed societies in Europe and the US face the same rising tide of hazard as the world’s poorest in the crowded coastal cities of Africa and Asia.

Estimate too low?

A mix of more extreme storms and storm surges, combined with ever higher sea levels, will sweep away the world’s beaches and turn millions of comfortable US citizens into climate refugees.

It is even possible that researchers have under-estimated the hazard, simply because satellite-based measurements may have misread precise land elevation: in some cases, too, coasts are sinking independently of sea level rise.

The latest study identifies a series of flood “hotspots” around the world. These include south-eastern China, Australia’s Northern Territory, Bangladesh, West Bengal and Gujarat in India, the US states of North Carolina, Virginia and Maryland, and north-west Europe including the UK, northern France and northern Germany. The new map of risks takes no account of existing flood defences, but highlights the levels of threat to come.

“This is critical research from a policy point of view, because it provides politicians with a credible estimate of the risks and costs we are facing, and a basis for taking action,” said Ian Young, an engineer at the University of Melbourne, and a co-author.

“This data should act as a wake-up call to inform policy at global and local government levels so that more flood defences can be built to safeguard coastal life and infrastructure.” – Climate News Network

Once again, researchers confirm that coastal dwellers can expect worse floods, more often and more expensively.

LONDON, 6 August, 2020 – In the next 80 years flooding around the planet’s land masses is likely to rise by almost 50%, endangering many millions of coastal dwellers.

If humans go on burning ever greater volumes of fossil fuels, while destroying ever more natural forest, then another 77 million people could be at risk of flooding, a rise of 52%.

And these floods – increasingly frequent and extending over greater areas – will put at risk cities, homes, resorts and industries valued at more than $14 trillion (£10.7tn).

This sum alone is worth 20% of global gross domestic product, the economist’s preferred indicator of economic health and wealth, according to a new study in the journal Scientific Reports.

The researchers built their argument on historic data from 681 tide-gauge stations around the world to model the growing hazard at 10,000 coastal locations.

“Compared with now, what we see as a one-in-100-year extreme flood event will be ten times more frequent because of climate change”

They conclude that the land area exposed to extreme flood will increase by more than 250,000 sq kms – an increase of 48% – to 800,000 sq kms, a threat to 252 million people.

“A warming climate is driving sea level rise because water expands as it warms, and glaciers are melting. Climate change is also increasing the frequency of extreme seas, which will further increase the risk of flooding,” said Ebru Kirezci of the University of Melbourne, Australia, who led the study.

“What the data and our model are saying is that compared with now, what we see as a one-in-100-year extreme flood event will be ten times more frequent because of climate change.”

None of this should come as a surprise to civic authorities, governments, hydraulic engineers and oceanographers: researchers have been warning for years that coastal floods driven by global heating will end up costing colossal and seemingly ever increasing sums.

On a global scale, and on regional examination, the story remains the same, and wealthy and developed societies in Europe and the US face the same rising tide of hazard as the world’s poorest in the crowded coastal cities of Africa and Asia.

Estimate too low?

A mix of more extreme storms and storm surges, combined with ever higher sea levels, will sweep away the world’s beaches and turn millions of comfortable US citizens into climate refugees.

It is even possible that researchers have under-estimated the hazard, simply because satellite-based measurements may have misread precise land elevation: in some cases, too, coasts are sinking independently of sea level rise.

The latest study identifies a series of flood “hotspots” around the world. These include south-eastern China, Australia’s Northern Territory, Bangladesh, West Bengal and Gujarat in India, the US states of North Carolina, Virginia and Maryland, and north-west Europe including the UK, northern France and northern Germany. The new map of risks takes no account of existing flood defences, but highlights the levels of threat to come.

“This is critical research from a policy point of view, because it provides politicians with a credible estimate of the risks and costs we are facing, and a basis for taking action,” said Ian Young, an engineer at the University of Melbourne, and a co-author.

“This data should act as a wake-up call to inform policy at global and local government levels so that more flood defences can be built to safeguard coastal life and infrastructure.” – Climate News Network

Antarctic melting could bring a much hotter future

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

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

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

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

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

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

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

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

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

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

Tell-tale line

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

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

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

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

Faster change ahead

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Tell-tale line

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

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

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

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

Faster change ahead

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

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

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

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

Threatened mangrove forests won’t protect coasts

Rising tides driven by global heating could swamp the mangrove forests – bad news for the natural world, and for humans.

LONDON, 17 June, 2020 – If sea levels go on rising at ever higher rates, then by 2050 the world’s mangrove forests could be obliterated, drowned by rising tides.

Mangrove forests cover between 140,000 and 200,000 square kilometres of the intertidal zones that fringe more than 100 tropical and subtropical countries, and have become among the richest ecosystems of the planet.

They are estimated to store at least 30 million tonnes of atmospheric carbon each year, and a couple of sq kms of this saltwater forest can harbour nursery space for what could become 100 tonnes of commercial fish catch every year.

They also provide shelter for a huge range of creatures, including an estimated 500 Bengal tigers in the vast Sundarbans mangrove forests along the Ganges-Brahmaputra delta.

And while most of the 80 or so species of mangrove tree can keep up with an annual sea level rise of around 5mm a year, they seem unlikely, on evidence from the past, to be able to survive a 10mm rise. Right now, the world is heading for the higher end of the scale.

Sheltering people

A second and separate study finds that, importantly for humans, along with coral reefs, the mangrove forests provide vital natural protection from tropical storms for 31 million very vulnerable people in North and Central America and the crowded archipelagos of Indonesia and the Philippines.

Researchers from Australia, China, Singapore and the US report in the journal Science that they looked at the evidence locked in the sediments in 78 locations from the last 10,000 years, to work out how mangrove forests have – through the millennia – responded to changes in sea level.

At the close of the last ice age, sea levels rose at 10mm a year and slowed to nearly stable conditions 4000 years ago.

In a high emissions scenario, by 2050 sea level rise would exceed 6mm: the scientists found a 90% probability that mangroves would not be able to grow fast enough to keep up. Nor – because of the development of coastal settlements worldwide – would the forests be able to shift inland.

“Simply put, it’s much cheaper to conserve a mangrove than build a sea wall”

“This research therefore highlights yet another compelling reason why countries must take urgent action to reduce carbon emissions,” said Benjamin Horton of Nanyang Technical University in Singapore., one of the researchers.

“Mangroves are among the most valuable of natural ecosystems, supporting coastal fisheries and biodiversity, while protecting shorelines from wave and storm attack across the tropics.”

As so often happens in research, confirmatory evidence of the importance of mangroves had been published only days earlier, in the Public Library of Science journal PLOS One.

US researchers found that – in the Gulf of Mexico and the Caribbean, off the coasts of east Africa and in the Indo-Pacific – a total of 30.9 million people lived in regions vulnerable to powerful tropical storms such as Typhoon Haiyan and Hurricane Harvey.

Of these, more than 8 million people were offered severe weather protection by shoreline mangrove forests and coral reefs, both of which absorb wave energy, reduce wave heights and keep coastal settlements safer.

Not enough protection

But only 38% of mangroves and 11% of coral reefs along the vulnerable coastlines are protected, they found.

A 100-metre screen of shoreline mangrove forest can reduce wave heights by as much as two-thirds. By 2100, coastal floods could be costing the world’s nations US$1 trillion a year in economic damage.

Geographers have argued for decades that natural protection is the most efficient way of saving lives and settlements from the storm surges and flooding associated with tropical cyclone extremes.

“Simply put”, said Holly Jones of Northern Illinois University, who led the research, “it’s much cheaper to conserve a mangrove than build a sea wall.” – Climate News Network

Rising tides driven by global heating could swamp the mangrove forests – bad news for the natural world, and for humans.

LONDON, 17 June, 2020 – If sea levels go on rising at ever higher rates, then by 2050 the world’s mangrove forests could be obliterated, drowned by rising tides.

Mangrove forests cover between 140,000 and 200,000 square kilometres of the intertidal zones that fringe more than 100 tropical and subtropical countries, and have become among the richest ecosystems of the planet.

They are estimated to store at least 30 million tonnes of atmospheric carbon each year, and a couple of sq kms of this saltwater forest can harbour nursery space for what could become 100 tonnes of commercial fish catch every year.

They also provide shelter for a huge range of creatures, including an estimated 500 Bengal tigers in the vast Sundarbans mangrove forests along the Ganges-Brahmaputra delta.

And while most of the 80 or so species of mangrove tree can keep up with an annual sea level rise of around 5mm a year, they seem unlikely, on evidence from the past, to be able to survive a 10mm rise. Right now, the world is heading for the higher end of the scale.

Sheltering people

A second and separate study finds that, importantly for humans, along with coral reefs, the mangrove forests provide vital natural protection from tropical storms for 31 million very vulnerable people in North and Central America and the crowded archipelagos of Indonesia and the Philippines.

Researchers from Australia, China, Singapore and the US report in the journal Science that they looked at the evidence locked in the sediments in 78 locations from the last 10,000 years, to work out how mangrove forests have – through the millennia – responded to changes in sea level.

At the close of the last ice age, sea levels rose at 10mm a year and slowed to nearly stable conditions 4000 years ago.

In a high emissions scenario, by 2050 sea level rise would exceed 6mm: the scientists found a 90% probability that mangroves would not be able to grow fast enough to keep up. Nor – because of the development of coastal settlements worldwide – would the forests be able to shift inland.

“Simply put, it’s much cheaper to conserve a mangrove than build a sea wall”

“This research therefore highlights yet another compelling reason why countries must take urgent action to reduce carbon emissions,” said Benjamin Horton of Nanyang Technical University in Singapore., one of the researchers.

“Mangroves are among the most valuable of natural ecosystems, supporting coastal fisheries and biodiversity, while protecting shorelines from wave and storm attack across the tropics.”

As so often happens in research, confirmatory evidence of the importance of mangroves had been published only days earlier, in the Public Library of Science journal PLOS One.

US researchers found that – in the Gulf of Mexico and the Caribbean, off the coasts of east Africa and in the Indo-Pacific – a total of 30.9 million people lived in regions vulnerable to powerful tropical storms such as Typhoon Haiyan and Hurricane Harvey.

Of these, more than 8 million people were offered severe weather protection by shoreline mangrove forests and coral reefs, both of which absorb wave energy, reduce wave heights and keep coastal settlements safer.

Not enough protection

But only 38% of mangroves and 11% of coral reefs along the vulnerable coastlines are protected, they found.

A 100-metre screen of shoreline mangrove forest can reduce wave heights by as much as two-thirds. By 2100, coastal floods could be costing the world’s nations US$1 trillion a year in economic damage.

Geographers have argued for decades that natural protection is the most efficient way of saving lives and settlements from the storm surges and flooding associated with tropical cyclone extremes.

“Simply put”, said Holly Jones of Northern Illinois University, who led the research, “it’s much cheaper to conserve a mangrove than build a sea wall.” – Climate News Network

Unanswered questions dog UK’s new nuclear plans

A French company has designs on the United Kingdom: new nuclear plans for more reactors, with British consumers footing the bill.

LONDON, 11 June, 2020 – The French company EDF, a company in a hurry, wants permission to start building two more reactors in the United Kingdom, and it hopes to save money – by arranging for British taxpayers to pay the capital costs of its new nuclear plans.

EDF is already building two reactors at Hinkley Point in the West of England, and it is hoping to transfer workers from that site to Suffolk, on the east coast, believing that will help it to save up to 20% of the construction cost of the two planned reactors, because everyone employed there will know already what to do.

The catch is that EDF has no money itself to finance the construction and wants the UK government to impose a new tax on British electricity consumers so that they will pay the cost through their electricity bills.

The UK has yet to decide whether to go ahead with this tax, euphemistically called a Regulated Asset Base. If adopted, what the scheme means is that the UK consumer will pay EDF’s bills rather than the company having to borrow the money from banks, which are increasingly unlikely to lend money to such expensive schemes because they take so long to build and promise little return.

Anxieties abound

Meanwhile EDF, which has a Chinese nuclear company as its junior partner, promises to create 25,000 jobs, including 1,000 apprenticeships during construction, and says 900 full-time jobs will be available when Sizewell C, as the station will be called, is complete.

If all goes to plan the company hopes to start work in 18 months and says the two reactors will take 10 years to build. It expects them to provide 7% of the UK’s electricity, enough for six million homes.

There are many objectors. Some say much of the coastline will be badly affected, including internationally important nature reserves. Others fear the site is highly vulnerable to sea level rise and therefore a danger to the public.

Local people also fear that the construction site, with its attendant lorry and commuter traffic, will disrupt their lives for a decade, destroying the important tourist trade.

Cheaper options

Other more strategic objections, which might weigh heavier with the government, are that nuclear power is very expensive and much cheaper and less controversial alternatives exist, particularly on-shore and off-shore wind and solar power, and biogas.

More importantly, a drive for energy efficiency, badly neglected in the UK at present, would render the whole project unnecessary.

The problem EDF has is its track record on construction and repairs. The type of reactor it plans to build, the European Pressurised Water Reactor, said by the company to be the most powerful in the world, is proving extremely difficult to build, and till now none has yet been completed outside China.

Construction is running more than 10 years late in both Finland and France, and costs continue to escalate.

“It is hard to understand why, when the scale of the problems became clear, EDF did not cut its losses and close the reactors”

EDF’s debts are now huge, so big that the French state is working out how to restructure the company by splitting it into a renewables arm (which is profitable) and a nuclear branch.

There are serious doubts about the reliability of EDF’s claims and timetables for fixing existing power stations and opening new ones. The company currently owns all of the UK’s operating nuclear reactors, most of which are near the end of their lives, and there are serious doubts about whether they are economic and in some cases even safe.

Two reactors at Hunterston in Scotland have serious cracking in the graphite blocks that are part of the control mechanism. The company has spent two years trying to justify continuing to operate the reactors to the Office for Nuclear Regulation (ONR).

Similarly, at the other end of the UK, at Dungeness in south-east England, the station is also closed for extensive repairs, an outage that was going to take weeks has now stretched to two years – and the start-up date has just been put back again.

Looking on the bright side

One of the features of all of EDF’s activities is the extraordinary optimism the company seems to have, particularly about when reactors will be finished or ready to restart after repairs. With the Hunterston reactors restart dates have been announced nine times, only to be postponed each time.

This track record led the Climate News Network to ask EDF some searching questions, including why they continued to offer optimistic start-up dates that were repeatedly postponed. We also asked why the company kept the Hunterston and Dungeness stations open at all, since repairing them was costly and they were already near the end of their operating lives.

We asked EDF: “At what point do you cut your losses and close the stations permanently?” After five days of pleading for more time to answer, it sent us already published press releases extolling the virtues of the plan to build Sizewell, and several comments.

On Dungeness B it said: “For the past two years we have undertaken a major investment programme at Dungeness to secure the station’s longer-term future. Since the start of the year we have made great progress in  tackling some of the complex problems our works identified.

Extensive repairs

“However we still have further engineering works to complete, and a detailed safety case to finalise, before we ask for restart approval from our regulator. Our present position for estimated return to service is 11 September for Reactor 22 and 21 September for Reactor 21.”

On Hunterston B, EDF said: “We are continuing to work constructively with the regulator to ensure the work at Hunterston B is done thoroughly and helps inform future decisions. The safety case for Hunterston B, Reactor 3, has been submitted to the ONR for its independent assessment.

“Since the first reactor was taken offline we have carried out the most extensive graphite inspection programme ever undertaken, the results of which have been fed into this case”, referring us to the information the company provides on graphite blocks.

The ONR could not answer for EDF on its estimated reactor re-opening dates, but on Hunterston it said it was looking at the safety case, would not be hurried and would not give permission to restart until it was satisfied it was safe to do so.

Unexpected snags

Stephen Thomas, professor of energy policy at the University of Greenwich, commented on the constantly postponed start-up dates for the ageing reactors:

“It is clear, given that shutdowns expected to take two months are now expected to take two years or more, that EDF has found huge unanticipated problems”, he said.

“It is hard to understand why, when the scale of the problems became clear, EDF did not cut its losses and close the reactors, but continues to pour money into plants to get a couple more years of operation out of plants highly likely to be loss-makers.

“It is depressing that ONR, which has a duty to keep the public informed on such important issues, chooses to hide behind bland statements such as that it will take as long as it takes, and that it will not comment on EDF’s decisions.” – Climate News Network

A French company has designs on the United Kingdom: new nuclear plans for more reactors, with British consumers footing the bill.

LONDON, 11 June, 2020 – The French company EDF, a company in a hurry, wants permission to start building two more reactors in the United Kingdom, and it hopes to save money – by arranging for British taxpayers to pay the capital costs of its new nuclear plans.

EDF is already building two reactors at Hinkley Point in the West of England, and it is hoping to transfer workers from that site to Suffolk, on the east coast, believing that will help it to save up to 20% of the construction cost of the two planned reactors, because everyone employed there will know already what to do.

The catch is that EDF has no money itself to finance the construction and wants the UK government to impose a new tax on British electricity consumers so that they will pay the cost through their electricity bills.

The UK has yet to decide whether to go ahead with this tax, euphemistically called a Regulated Asset Base. If adopted, what the scheme means is that the UK consumer will pay EDF’s bills rather than the company having to borrow the money from banks, which are increasingly unlikely to lend money to such expensive schemes because they take so long to build and promise little return.

Anxieties abound

Meanwhile EDF, which has a Chinese nuclear company as its junior partner, promises to create 25,000 jobs, including 1,000 apprenticeships during construction, and says 900 full-time jobs will be available when Sizewell C, as the station will be called, is complete.

If all goes to plan the company hopes to start work in 18 months and says the two reactors will take 10 years to build. It expects them to provide 7% of the UK’s electricity, enough for six million homes.

There are many objectors. Some say much of the coastline will be badly affected, including internationally important nature reserves. Others fear the site is highly vulnerable to sea level rise and therefore a danger to the public.

Local people also fear that the construction site, with its attendant lorry and commuter traffic, will disrupt their lives for a decade, destroying the important tourist trade.

Cheaper options

Other more strategic objections, which might weigh heavier with the government, are that nuclear power is very expensive and much cheaper and less controversial alternatives exist, particularly on-shore and off-shore wind and solar power, and biogas.

More importantly, a drive for energy efficiency, badly neglected in the UK at present, would render the whole project unnecessary.

The problem EDF has is its track record on construction and repairs. The type of reactor it plans to build, the European Pressurised Water Reactor, said by the company to be the most powerful in the world, is proving extremely difficult to build, and till now none has yet been completed outside China.

Construction is running more than 10 years late in both Finland and France, and costs continue to escalate.

“It is hard to understand why, when the scale of the problems became clear, EDF did not cut its losses and close the reactors”

EDF’s debts are now huge, so big that the French state is working out how to restructure the company by splitting it into a renewables arm (which is profitable) and a nuclear branch.

There are serious doubts about the reliability of EDF’s claims and timetables for fixing existing power stations and opening new ones. The company currently owns all of the UK’s operating nuclear reactors, most of which are near the end of their lives, and there are serious doubts about whether they are economic and in some cases even safe.

Two reactors at Hunterston in Scotland have serious cracking in the graphite blocks that are part of the control mechanism. The company has spent two years trying to justify continuing to operate the reactors to the Office for Nuclear Regulation (ONR).

Similarly, at the other end of the UK, at Dungeness in south-east England, the station is also closed for extensive repairs, an outage that was going to take weeks has now stretched to two years – and the start-up date has just been put back again.

Looking on the bright side

One of the features of all of EDF’s activities is the extraordinary optimism the company seems to have, particularly about when reactors will be finished or ready to restart after repairs. With the Hunterston reactors restart dates have been announced nine times, only to be postponed each time.

This track record led the Climate News Network to ask EDF some searching questions, including why they continued to offer optimistic start-up dates that were repeatedly postponed. We also asked why the company kept the Hunterston and Dungeness stations open at all, since repairing them was costly and they were already near the end of their operating lives.

We asked EDF: “At what point do you cut your losses and close the stations permanently?” After five days of pleading for more time to answer, it sent us already published press releases extolling the virtues of the plan to build Sizewell, and several comments.

On Dungeness B it said: “For the past two years we have undertaken a major investment programme at Dungeness to secure the station’s longer-term future. Since the start of the year we have made great progress in  tackling some of the complex problems our works identified.

Extensive repairs

“However we still have further engineering works to complete, and a detailed safety case to finalise, before we ask for restart approval from our regulator. Our present position for estimated return to service is 11 September for Reactor 22 and 21 September for Reactor 21.”

On Hunterston B, EDF said: “We are continuing to work constructively with the regulator to ensure the work at Hunterston B is done thoroughly and helps inform future decisions. The safety case for Hunterston B, Reactor 3, has been submitted to the ONR for its independent assessment.

“Since the first reactor was taken offline we have carried out the most extensive graphite inspection programme ever undertaken, the results of which have been fed into this case”, referring us to the information the company provides on graphite blocks.

The ONR could not answer for EDF on its estimated reactor re-opening dates, but on Hunterston it said it was looking at the safety case, would not be hurried and would not give permission to restart until it was satisfied it was safe to do so.

Unexpected snags

Stephen Thomas, professor of energy policy at the University of Greenwich, commented on the constantly postponed start-up dates for the ageing reactors:

“It is clear, given that shutdowns expected to take two months are now expected to take two years or more, that EDF has found huge unanticipated problems”, he said.

“It is hard to understand why, when the scale of the problems became clear, EDF did not cut its losses and close the reactors, but continues to pour money into plants to get a couple more years of operation out of plants highly likely to be loss-makers.

“It is depressing that ONR, which has a duty to keep the public informed on such important issues, chooses to hide behind bland statements such as that it will take as long as it takes, and that it will not comment on EDF’s decisions.” – Climate News Network

Human action will decide how much sea levels rise

Sea levels will go on rising, because of human action. By how much, though, depends on what humans do next.

LONDON, 21 May 2020 – It’s a racing certainty that sea levels everywhere will go on climbing. Unless the world’s nations act to contain global warming, by 2100 the tides around the world will be one metre higher. And by 2300, they could be five metres higher.

Humans will not be able to blame natural causes: if beaches wash away and coastal towns flood, it will be because of deliberate human inaction.

And even if the 195 nations that met in Paris in 2015 and vowed to limit global warming to “well below” a maximum of 2°C by 2100 actually keep their promise, sea levels around the world will almost certainly rise by at least half a metre, as ever warmer oceans expand, and mountain glaciers and polar icecaps continue to melt.

The predicted levels are not new – individual research teams and the Intergovernmental Panel on Climate Change have said as much many times – but they represent a second and closer look, by 106 experts, at the forecasts for the future.

The charge of human complicity in sea level rise, too, is not new, but science has a way of continuously re-examining its own conclusions to see if they could be wrong. And the message is: they are not wrong.

“This provides a great deal of hope for the future, as well as strong motivation to act now”

Researchers from Hong Kong, Ireland, the UK, the US and Germany joined scientists from Singapore to consider, once again, what could happen to the world’s oceans under two scenarios: one in which global warming – already at least 1°C higher now than for most of human history – rose by no more than 2°C altogether, and one in which humankind went on burning fossil fuels and destroying tropical rainforests at ever greater rates.

The conclusion? They report in the journal Climate and Atmospheric Science that at the 2°C limit, seas will rise by 0.5 metres by 2100 and two metres by 2300.

If temperatures by 2100 reach 4.5°C, then by the century’s end the tides could reach anywhere between 0.6 and 1.3 metres above present levels. Two centuries on, the high tide mark could be anywhere between 1.7 and 5.6 metres above the present.

And these are the judgments of 106 scientists, each of whom has published at least six peer-reviewed scientific studies of future sea level rise in the last six years.

“We know that the planet will see additional sea level rise in the future. But there are stark differences in the amount of sea level rise experts project for low emissions compared to high emissions,” said one of the scientists, Andra Garner of Rowan University in the US.

Lessons from prehistory

“This provides a great deal of hope for the future, as well as strong motivation to act now to avoid the more severe impacts of rising sea levels.”

Quite separately, researchers in the US report in the journal Science Advances that they too, took a closer look at puzzles posed by past sea level change. Long before humans ever started burning coal, oil and natural gas, the ice caps retreated, and the seas rose.

The scientists reconstructed the history of sea levels and glaciation since the end of the Cretaceous era 60 million or so years ago, and matched them to estimated carbon dioxide levels long before the emergence of any human ancestry.

They concluded that all the changes in the past had natural explanations, but not the changes happening now.

Kenneth Miller of Rutgers University who led the study said: “Although carbon dioxide levels had an important influence on ice-free periods, minor variations in the Earth’s orbit were the dominant factor in terms of ice volume and sea level changes – until modern times.” – Climate News Network

Sea levels will go on rising, because of human action. By how much, though, depends on what humans do next.

LONDON, 21 May 2020 – It’s a racing certainty that sea levels everywhere will go on climbing. Unless the world’s nations act to contain global warming, by 2100 the tides around the world will be one metre higher. And by 2300, they could be five metres higher.

Humans will not be able to blame natural causes: if beaches wash away and coastal towns flood, it will be because of deliberate human inaction.

And even if the 195 nations that met in Paris in 2015 and vowed to limit global warming to “well below” a maximum of 2°C by 2100 actually keep their promise, sea levels around the world will almost certainly rise by at least half a metre, as ever warmer oceans expand, and mountain glaciers and polar icecaps continue to melt.

The predicted levels are not new – individual research teams and the Intergovernmental Panel on Climate Change have said as much many times – but they represent a second and closer look, by 106 experts, at the forecasts for the future.

The charge of human complicity in sea level rise, too, is not new, but science has a way of continuously re-examining its own conclusions to see if they could be wrong. And the message is: they are not wrong.

“This provides a great deal of hope for the future, as well as strong motivation to act now”

Researchers from Hong Kong, Ireland, the UK, the US and Germany joined scientists from Singapore to consider, once again, what could happen to the world’s oceans under two scenarios: one in which global warming – already at least 1°C higher now than for most of human history – rose by no more than 2°C altogether, and one in which humankind went on burning fossil fuels and destroying tropical rainforests at ever greater rates.

The conclusion? They report in the journal Climate and Atmospheric Science that at the 2°C limit, seas will rise by 0.5 metres by 2100 and two metres by 2300.

If temperatures by 2100 reach 4.5°C, then by the century’s end the tides could reach anywhere between 0.6 and 1.3 metres above present levels. Two centuries on, the high tide mark could be anywhere between 1.7 and 5.6 metres above the present.

And these are the judgments of 106 scientists, each of whom has published at least six peer-reviewed scientific studies of future sea level rise in the last six years.

“We know that the planet will see additional sea level rise in the future. But there are stark differences in the amount of sea level rise experts project for low emissions compared to high emissions,” said one of the scientists, Andra Garner of Rowan University in the US.

Lessons from prehistory

“This provides a great deal of hope for the future, as well as strong motivation to act now to avoid the more severe impacts of rising sea levels.”

Quite separately, researchers in the US report in the journal Science Advances that they too, took a closer look at puzzles posed by past sea level change. Long before humans ever started burning coal, oil and natural gas, the ice caps retreated, and the seas rose.

The scientists reconstructed the history of sea levels and glaciation since the end of the Cretaceous era 60 million or so years ago, and matched them to estimated carbon dioxide levels long before the emergence of any human ancestry.

They concluded that all the changes in the past had natural explanations, but not the changes happening now.

Kenneth Miller of Rutgers University who led the study said: “Although carbon dioxide levels had an important influence on ice-free periods, minor variations in the Earth’s orbit were the dominant factor in terms of ice volume and sea level changes – until modern times.” – Climate News Network

Sea level rise threatens UK nuclear reactor plans

Sea level rise may consign the planned UK site for two large nuclear reactors to vanish beneath the waves.

LONDON, 28 April, 2020 – Controversial plans by the French nuclear giant EDF to build two of its massive new reactors on the low-lying east coast of England are causing alarm: the shore is eroding and local people fear sea level rise could maroon the station on an island.

A newly published paper adds weight to the objections of two local government bodies, East Suffolk Council and Suffolk County Council, which have already lodged objections to EDF’s plans because they fear the proposed sea defences for the new station, Sizewell C, will be inadequate.

EDF, which is currently expecting the go-ahead to start building the station from the British government, says it has done its own expert assessment, had its calculations independently checked, and is satisfied that the coast is stable and the planned concrete sea defences will be adequate.

The argument is whether the coastal banks which prevent storm waves hitting this part of the coast will remain intact for the next 150 years – roughly the life of the station, taking into account 20 years of construction, 60 years of operation and then the time needed to decommission it.

The paper is the work of a structural engineer, Nick Scarr, a member of the Nuclear Consulting Group, which is an independent, non-profit virtual institute that provides expert research and analysis of nuclear issues.

As relevant, though, is his knowledge of the coastal waters of Suffolk, where he spends time sailing. He believes the coast is inherently unstable.

Catastrophic accident risk

With sea level rise and storm surges, he says, the site will become an island with its defences eroded by the sea well before the station reaches the end of its active life, risking a catastrophic accident, which is why he wrote his report.

He told the Climate News Network: “Any sailor, or lifeboat crew, knows that East Coast banks need respect – they have dynamic patterns, and even the latest charts cannot be accurate for long.

“I was deeply concerned by EDF’s premise that there is micro-stability at the Sizewell site, which makes it suitable for new-build nuclear. It is true if you restrict analysis to recent historical data, but it is false if you look at longer-term data and evidence-based climate science predictions.

“Climate science not only tells us that storm surges have a higher median level to work from, but that they will also render the banks ineffective for mitigating wave power on the Sizewell foreshore (because of reduced friction, as the water depth is greater).”

The longer-term data Scarr mentions are not altogether reassuring. Less than 10 miles from the site are the remains of Dunwich, once a thriving medieval port that disappeared in 1338 because of coastal erosion and a huge storm.

Nick Scarr added: “Note that Sizewell security needs to last at least from now to the year 2150. A shorter period than this, 1868-1992, shown in hydrographic charting, tells us clearly how unstable the offshore banks are over a longer time frame, and that is without sea level rise.”

“Any sailor, or lifeboat crew, knows that East Coast banks need respect – they have dynamic patterns, and even the latest charts cannot be accurate for long”

Sea level rise is expected to be up to a metre on this coast by the end of the century, but that is only part of the problem – the “once in a century” storm surges are expected to occur as often as once a year by 2050.

This is not the first time that ambitious plans by the government to build nuclear power stations on the British coast have been questioned. A proposed station at Dungeness in Kent, on England’s south-east coast,  has already been shelved because the existing station there is in danger from the sea.

The Suffolk site already has two stations. Sizewell A has been closed and is being decommissioned. The second, Sizewell B,  owned by EDF, has been operating since the early 1990s and is due to close some time in the 2030s.

The new reactors, together called Sizewell C, will be built further out to sea than A and B and will rely on an undersea ridge, a coralline crag, as a bastion against storm waves crashing into the station.

EDF’s contention that the site is safe is partly based on a report by engineers Mott Macdonald, compiled in 2014 and based on historical data, which says that this undersea ridge is stable and will continue to be a form of natural coastal defence.

However, East Suffolk and Suffolk County Councils, in their joint response to EDF’s consultation, make it clear that Sizewell C’s development has not in their view been shown to be able to be  protected from erosion or flood risk over the site’s life.

Fuel storage problem

Scarr’s report goes further, concluding: “This threat to the Sizewell foreshore is clearly an untenable risk.”

One contentious issue on nuclear sites, including those at Sizewell, is the need for decades-long storage of large quantities of highly dangerous spent nuclear fuel in cooling ponds once it is removed from the reactors. Currently the UK has no such disposal route.

Asked about Starr’s report and the councils’ objections, EDF told the Network: “The design of the power station, including its sea defence and the raised platform it will be built on, will protect Sizewell C from flooding.”

It added: “Sizewell C will safely manage the spent fuel from the station on the site for its lifetime, or until a deep geological repository becomes available.

“Sizewell is located within a stable part of the Suffolk coastline between two hard points and the offshore bank of sediment, the Dunwich-Sizewell bank.  We have undertaken extensive studies of the coastline in developing our plans.

“We have performed a great deal of modelling to forecast potential future scenarios along the Sizewell coast, with and without Sizewell C, to fully assess the effect of the station on coastal processes. We then asked independent experts to critique the forecasts to provide the very best assessment of long-term coastal change.

Dungeness jeopardy

“When built, the permanent sea defences would protect the power station from a 1 in 10,000-year storm event, including climate change and sea level rise. We’ve designed flexibility into our permanent coastal sea defence, meaning it could be raised during the lifetime of Sizewell C if needed.”

Another of EDF’s existing reactors, at Dungeness, which is built on a vast shingle bank, was taken offline seven years ago for five months while an emergency sea wall was built to prevent it being flooded.

For decades the defences of the twin reactors have had constantly to be reinforced because the shingle banks on which they stand are being eroded by the sea.

That station was designed more than 30 years ago, before scientists realised the dangers that sea level rise posed, and apparently without understanding how the shingle constantly moves.

Although it is due to shut later this decade it will still represent a serious danger to the public for another century until it can be safely decommissioned and demolished.

During that time millions of pounds will have to be spent making sure it is not overwhelmed by storms and sea level rise. – Climate News Network

Sea level rise may consign the planned UK site for two large nuclear reactors to vanish beneath the waves.

LONDON, 28 April, 2020 – Controversial plans by the French nuclear giant EDF to build two of its massive new reactors on the low-lying east coast of England are causing alarm: the shore is eroding and local people fear sea level rise could maroon the station on an island.

A newly published paper adds weight to the objections of two local government bodies, East Suffolk Council and Suffolk County Council, which have already lodged objections to EDF’s plans because they fear the proposed sea defences for the new station, Sizewell C, will be inadequate.

EDF, which is currently expecting the go-ahead to start building the station from the British government, says it has done its own expert assessment, had its calculations independently checked, and is satisfied that the coast is stable and the planned concrete sea defences will be adequate.

The argument is whether the coastal banks which prevent storm waves hitting this part of the coast will remain intact for the next 150 years – roughly the life of the station, taking into account 20 years of construction, 60 years of operation and then the time needed to decommission it.

The paper is the work of a structural engineer, Nick Scarr, a member of the Nuclear Consulting Group, which is an independent, non-profit virtual institute that provides expert research and analysis of nuclear issues.

As relevant, though, is his knowledge of the coastal waters of Suffolk, where he spends time sailing. He believes the coast is inherently unstable.

Catastrophic accident risk

With sea level rise and storm surges, he says, the site will become an island with its defences eroded by the sea well before the station reaches the end of its active life, risking a catastrophic accident, which is why he wrote his report.

He told the Climate News Network: “Any sailor, or lifeboat crew, knows that East Coast banks need respect – they have dynamic patterns, and even the latest charts cannot be accurate for long.

“I was deeply concerned by EDF’s premise that there is micro-stability at the Sizewell site, which makes it suitable for new-build nuclear. It is true if you restrict analysis to recent historical data, but it is false if you look at longer-term data and evidence-based climate science predictions.

“Climate science not only tells us that storm surges have a higher median level to work from, but that they will also render the banks ineffective for mitigating wave power on the Sizewell foreshore (because of reduced friction, as the water depth is greater).”

The longer-term data Scarr mentions are not altogether reassuring. Less than 10 miles from the site are the remains of Dunwich, once a thriving medieval port that disappeared in 1338 because of coastal erosion and a huge storm.

Nick Scarr added: “Note that Sizewell security needs to last at least from now to the year 2150. A shorter period than this, 1868-1992, shown in hydrographic charting, tells us clearly how unstable the offshore banks are over a longer time frame, and that is without sea level rise.”

“Any sailor, or lifeboat crew, knows that East Coast banks need respect – they have dynamic patterns, and even the latest charts cannot be accurate for long”

Sea level rise is expected to be up to a metre on this coast by the end of the century, but that is only part of the problem – the “once in a century” storm surges are expected to occur as often as once a year by 2050.

This is not the first time that ambitious plans by the government to build nuclear power stations on the British coast have been questioned. A proposed station at Dungeness in Kent, on England’s south-east coast,  has already been shelved because the existing station there is in danger from the sea.

The Suffolk site already has two stations. Sizewell A has been closed and is being decommissioned. The second, Sizewell B,  owned by EDF, has been operating since the early 1990s and is due to close some time in the 2030s.

The new reactors, together called Sizewell C, will be built further out to sea than A and B and will rely on an undersea ridge, a coralline crag, as a bastion against storm waves crashing into the station.

EDF’s contention that the site is safe is partly based on a report by engineers Mott Macdonald, compiled in 2014 and based on historical data, which says that this undersea ridge is stable and will continue to be a form of natural coastal defence.

However, East Suffolk and Suffolk County Councils, in their joint response to EDF’s consultation, make it clear that Sizewell C’s development has not in their view been shown to be able to be  protected from erosion or flood risk over the site’s life.

Fuel storage problem

Scarr’s report goes further, concluding: “This threat to the Sizewell foreshore is clearly an untenable risk.”

One contentious issue on nuclear sites, including those at Sizewell, is the need for decades-long storage of large quantities of highly dangerous spent nuclear fuel in cooling ponds once it is removed from the reactors. Currently the UK has no such disposal route.

Asked about Starr’s report and the councils’ objections, EDF told the Network: “The design of the power station, including its sea defence and the raised platform it will be built on, will protect Sizewell C from flooding.”

It added: “Sizewell C will safely manage the spent fuel from the station on the site for its lifetime, or until a deep geological repository becomes available.

“Sizewell is located within a stable part of the Suffolk coastline between two hard points and the offshore bank of sediment, the Dunwich-Sizewell bank.  We have undertaken extensive studies of the coastline in developing our plans.

“We have performed a great deal of modelling to forecast potential future scenarios along the Sizewell coast, with and without Sizewell C, to fully assess the effect of the station on coastal processes. We then asked independent experts to critique the forecasts to provide the very best assessment of long-term coastal change.

Dungeness jeopardy

“When built, the permanent sea defences would protect the power station from a 1 in 10,000-year storm event, including climate change and sea level rise. We’ve designed flexibility into our permanent coastal sea defence, meaning it could be raised during the lifetime of Sizewell C if needed.”

Another of EDF’s existing reactors, at Dungeness, which is built on a vast shingle bank, was taken offline seven years ago for five months while an emergency sea wall was built to prevent it being flooded.

For decades the defences of the twin reactors have had constantly to be reinforced because the shingle banks on which they stand are being eroded by the sea.

That station was designed more than 30 years ago, before scientists realised the dangers that sea level rise posed, and apparently without understanding how the shingle constantly moves.

Although it is due to shut later this decade it will still represent a serious danger to the public for another century until it can be safely decommissioned and demolished.

During that time millions of pounds will have to be spent making sure it is not overwhelmed by storms and sea level rise. – Climate News Network

US coasts face far more frequent severe floods

This story is a part of Covering Climate Now’s week of coverage focused on Climate Solutions, to mark the 50th anniversary of Earth Day. Covering Climate Now is a global journalism collaboration committed to strengthening coverage of the climate story.

 

For US coasts, high-water hazards have just become more hazardous: a lot more hazardous, say scientists.

LONDON, 24 April, 2020 − A new study of high-water levels on US coasts in 200 regions brings ominous news for those who live in vulnerable towns and cities.

By 2050, floods expected perhaps once every 50 years will happen almost every year in nearly three fourths of all the coasts under study.

And by 2100, the kind of extreme high tides that now happen once in a lifetime could wash over the streets and gardens of 93% of these communities, almost every day.

The message, from researchers led by the US Geological Survey, is that sea levels will go on rising steadily by millimetres every year, but the number of extreme flooding events could double every five years.

Researchers outline their argument in the journal Scientific Reports. They looked at the data routinely collected from 202 tide gauges distributed around the US coasts and then extended the tidal levels forward in time in line with predictions based on global sea level rise that will inevitably accompany ever-increasing global average temperatures, driven by greenhouse gas emissions from fossil fuel use.

“The impact of this finding bears repeating: sea level rise will likely cause ‘once-in-a-lifetime’ coastal flooding events to occur nearly every day before 2100”

Other scientists have warned that the damage from coastal flooding, storm surges and marine invasion will rise to colossal levels by the century’s end, that routine high-tide floods will become increasingly common, and that up to 13 million US citizens now in coastal settlements could become climate refugees.

But researchers based in Chicago, Santa Cruz and Hawaii wanted more than that: they wanted to know what sea level rise will do, as the waters lap ever higher, from year to year.

“Sea level rise is slow, yet consequential and accelerating,” they point out. “Upper end sea level rise scenarios could displace hundreds of millions of people by the end of the 21st century. However, even small amounts of sea level rise can disproportionately increase coastal flood frequency.”

The researchers selected 202 sites, most of them in sheltered harbours or bays, for their tide data: that way their record reflected the highest tides and storm surges, but not the haphazard readings of waves.

They concentrated on what they called “extreme water-level events” of the kind that happened once every 50 years, because most US coastal engineering work is based on that kind of hazard frequency. And then they started doing the calculations.

Exponential hazard growth

For nine out of 10 locations, the difference between the kind of flood that happened every 50 years and the sort that occurred maybe once a year was about half a metre. For 73% of their chosen tide gauges, the difference between the daily highest tide and the once-every-50-years event was less than a metre. Most projections for sea level rise worldwide by the end of the century are higher than a metre.

Once the researchers had set their algorithms to work, they found that even in median sea-level rise scenarios, the hazards grew exponentially. They found that all tidal stations would by 2050 be recording what remain for the moment 50-year events, every year. When they set the timetable to 2100, 93% of their locations would be recording a once-in-50-years flood every day.

“The impact of this finding bears repeating: sea level rise will likely cause ‘once-in-a-lifetime’ coastal flooding events to occur nearly every day before 2100,” they warn.

This would have profound consequences for what they call extreme events. And even in ordinary circumstances, beaches are increasingly likely to be washed away, and cliffs eroded.

The researchers conclude: “Our society has yet to fully comprehend the imminence of the projected regime shifts in coastal hazards and the consequences thereof.” − Climate News Network

This story is a part of Covering Climate Now’s week of coverage focused on Climate Solutions, to mark the 50th anniversary of Earth Day. Covering Climate Now is a global journalism collaboration committed to strengthening coverage of the climate story.

 

For US coasts, high-water hazards have just become more hazardous: a lot more hazardous, say scientists.

LONDON, 24 April, 2020 − A new study of high-water levels on US coasts in 200 regions brings ominous news for those who live in vulnerable towns and cities.

By 2050, floods expected perhaps once every 50 years will happen almost every year in nearly three fourths of all the coasts under study.

And by 2100, the kind of extreme high tides that now happen once in a lifetime could wash over the streets and gardens of 93% of these communities, almost every day.

The message, from researchers led by the US Geological Survey, is that sea levels will go on rising steadily by millimetres every year, but the number of extreme flooding events could double every five years.

Researchers outline their argument in the journal Scientific Reports. They looked at the data routinely collected from 202 tide gauges distributed around the US coasts and then extended the tidal levels forward in time in line with predictions based on global sea level rise that will inevitably accompany ever-increasing global average temperatures, driven by greenhouse gas emissions from fossil fuel use.

“The impact of this finding bears repeating: sea level rise will likely cause ‘once-in-a-lifetime’ coastal flooding events to occur nearly every day before 2100”

Other scientists have warned that the damage from coastal flooding, storm surges and marine invasion will rise to colossal levels by the century’s end, that routine high-tide floods will become increasingly common, and that up to 13 million US citizens now in coastal settlements could become climate refugees.

But researchers based in Chicago, Santa Cruz and Hawaii wanted more than that: they wanted to know what sea level rise will do, as the waters lap ever higher, from year to year.

“Sea level rise is slow, yet consequential and accelerating,” they point out. “Upper end sea level rise scenarios could displace hundreds of millions of people by the end of the 21st century. However, even small amounts of sea level rise can disproportionately increase coastal flood frequency.”

The researchers selected 202 sites, most of them in sheltered harbours or bays, for their tide data: that way their record reflected the highest tides and storm surges, but not the haphazard readings of waves.

They concentrated on what they called “extreme water-level events” of the kind that happened once every 50 years, because most US coastal engineering work is based on that kind of hazard frequency. And then they started doing the calculations.

Exponential hazard growth

For nine out of 10 locations, the difference between the kind of flood that happened every 50 years and the sort that occurred maybe once a year was about half a metre. For 73% of their chosen tide gauges, the difference between the daily highest tide and the once-every-50-years event was less than a metre. Most projections for sea level rise worldwide by the end of the century are higher than a metre.

Once the researchers had set their algorithms to work, they found that even in median sea-level rise scenarios, the hazards grew exponentially. They found that all tidal stations would by 2050 be recording what remain for the moment 50-year events, every year. When they set the timetable to 2100, 93% of their locations would be recording a once-in-50-years flood every day.

“The impact of this finding bears repeating: sea level rise will likely cause ‘once-in-a-lifetime’ coastal flooding events to occur nearly every day before 2100,” they warn.

This would have profound consequences for what they call extreme events. And even in ordinary circumstances, beaches are increasingly likely to be washed away, and cliffs eroded.

The researchers conclude: “Our society has yet to fully comprehend the imminence of the projected regime shifts in coastal hazards and the consequences thereof.” − Climate News Network