Category Archives: Oceans

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

Plastic waste now litters Antarctic shore

From the deep Mediterranean marine mud to the desolate beaches of the Southern Ocean, plastic waste now gets everywhere.

LONDON, 12 May, 2020 – The throwaway society now has a global reach. British and German scientists have found astonishing concentrations of plastic waste in the form of tiny fibres on the sea floor. In just one square metre of marine ooze, they have counted as many as 1.9 million fragments less than a millimetre in length.

And two studies have identified sickening levels of plastic waste in the Southern Ocean that washes around Antarctica. One team reports ever greater counts of debris on the beaches of islands in South Georgia and South Orkney; the other on the increasing quantities ingested by the wandering albatross and the giant petrel, two iconic birds of the south polar seas.

An estimated 10 million tonnes of discarded food wrapping, drinking straws, disposable cups, bottles, carrier bags and fishing gear are tipped into the sea each year: plastic waste has now been found in all the world’s oceans, and even in the polar ice, an indestructible reminder of human impact on the natural world.

Tiny textile particles or microfibres of plastic have been found in every sampled litre of sea water, in the stomachs of seabirds and in the bellies of whales.

In fact the visible debris – the polystyrene cups and drinking straws and carrier bags floating on or near the surface – is thought to account for a tiny proportion of the total. Around 99% is thought to be in the deep oceans.

“Microplastics are not uniformly distributed across the study area; instead they are distributed by powerful seafloor currents that concentrate them in certain areas”

And researchers now report in the journal Science that they have found an indicator as to the final fate of most of it. They collected sediment at depths of up to 900 metres from the floor of the Tyrrhenian Sea to the west of the Italian peninsula and began counting the particles of indestructible polymer material in the marine mud, carried there by deep ocean currents.

“Almost everybody has heard of the infamous ‘garbage patches’ of floating plastic, but we were shocked at the high concentrations of microplastics we found on the sea floor,” said Ian Kane of the University of Manchester, in the UK, one of the authors.

“We discovered that microplastics are not uniformly distributed across the study area; instead they are distributed by powerful seafloor currents that concentrate them in certain areas.”

These same deep currents also carry oxygen-rich water and nutrients, which suggests that toxic microplastics are being carried into vital deep ecosystems. But the surface-borne debris has far-reaching consequences too.

Remedial efforts

British and Australian scientists who made surveys over three decades of beached plastic, metal, glass, paper and rubber at locations in the Southern Ocean report in the journal Environment International that between 1989 and March 2019, they recovered 10,112 items of waste weighing in total more than 100kg from Bird Island off South Georgia, and 1,304 items weighing in all 268 kg from the remote shores of Signy Island in the South Orkney archipelago.

Almost 90% of the total was plastic. The peak of the debris count was in the 1990s, which suggests that some attempts have been made to reduce the levels discarded from shipping and other sources.

And a second study in the same journal reports that in the same 30 years, levels of plastic pollution had been consumed in increasing quantities by two out of three species of albatross, and another sea bird.

Annual intake in Diomedea exulans, the wandering albatross, had increased 14-fold, and in the giant petrel Macronectes giganteus the intake had increased six-fold.

“Our study adds to the growing body of evidence that fishing and other vessels make a major contribution to plastic pollution,” said Richard Phillips of the British Antarctic Survey. “It’s clear that marine plastics are a threat to seabirds and other wildlife, and more needs to be done.” – Climate News Network

From the deep Mediterranean marine mud to the desolate beaches of the Southern Ocean, plastic waste now gets everywhere.

LONDON, 12 May, 2020 – The throwaway society now has a global reach. British and German scientists have found astonishing concentrations of plastic waste in the form of tiny fibres on the sea floor. In just one square metre of marine ooze, they have counted as many as 1.9 million fragments less than a millimetre in length.

And two studies have identified sickening levels of plastic waste in the Southern Ocean that washes around Antarctica. One team reports ever greater counts of debris on the beaches of islands in South Georgia and South Orkney; the other on the increasing quantities ingested by the wandering albatross and the giant petrel, two iconic birds of the south polar seas.

An estimated 10 million tonnes of discarded food wrapping, drinking straws, disposable cups, bottles, carrier bags and fishing gear are tipped into the sea each year: plastic waste has now been found in all the world’s oceans, and even in the polar ice, an indestructible reminder of human impact on the natural world.

Tiny textile particles or microfibres of plastic have been found in every sampled litre of sea water, in the stomachs of seabirds and in the bellies of whales.

In fact the visible debris – the polystyrene cups and drinking straws and carrier bags floating on or near the surface – is thought to account for a tiny proportion of the total. Around 99% is thought to be in the deep oceans.

“Microplastics are not uniformly distributed across the study area; instead they are distributed by powerful seafloor currents that concentrate them in certain areas”

And researchers now report in the journal Science that they have found an indicator as to the final fate of most of it. They collected sediment at depths of up to 900 metres from the floor of the Tyrrhenian Sea to the west of the Italian peninsula and began counting the particles of indestructible polymer material in the marine mud, carried there by deep ocean currents.

“Almost everybody has heard of the infamous ‘garbage patches’ of floating plastic, but we were shocked at the high concentrations of microplastics we found on the sea floor,” said Ian Kane of the University of Manchester, in the UK, one of the authors.

“We discovered that microplastics are not uniformly distributed across the study area; instead they are distributed by powerful seafloor currents that concentrate them in certain areas.”

These same deep currents also carry oxygen-rich water and nutrients, which suggests that toxic microplastics are being carried into vital deep ecosystems. But the surface-borne debris has far-reaching consequences too.

Remedial efforts

British and Australian scientists who made surveys over three decades of beached plastic, metal, glass, paper and rubber at locations in the Southern Ocean report in the journal Environment International that between 1989 and March 2019, they recovered 10,112 items of waste weighing in total more than 100kg from Bird Island off South Georgia, and 1,304 items weighing in all 268 kg from the remote shores of Signy Island in the South Orkney archipelago.

Almost 90% of the total was plastic. The peak of the debris count was in the 1990s, which suggests that some attempts have been made to reduce the levels discarded from shipping and other sources.

And a second study in the same journal reports that in the same 30 years, levels of plastic pollution had been consumed in increasing quantities by two out of three species of albatross, and another sea bird.

Annual intake in Diomedea exulans, the wandering albatross, had increased 14-fold, and in the giant petrel Macronectes giganteus the intake had increased six-fold.

“Our study adds to the growing body of evidence that fishing and other vessels make a major contribution to plastic pollution,” said Richard Phillips of the British Antarctic Survey. “It’s clear that marine plastics are a threat to seabirds and other wildlife, and more needs to be done.” – 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

Entire wild systems at risk from rising global heat

Rising global heat raises risks to the creatures and ecosystems that sustain human society. Collapse could be sudden and near-total.

LONDON, 14 April, 2020 – Worldwide, entire ecosystems could collapse as the planetary thermometer soars: rising global heat could see the Earth’s average temperature rise by 4°C (right now the world is heading for a rise of more than three degrees).

And then one in six of the complex communities of plants and animals in wetlands, grasslands, forests or oceans could drastically alter or fail.

That is because at such temperatures more than one in five of the creatures in that network of co-dependencies would in the same decade experience temperatures beyond their normal tolerance levels.

The prediction is based on data that pinpoint the geographical ranges of 30,652 birds, mammals, reptiles, amphibians, fish and plants, and climate data from 1850 to 2005.

“We found that climate change risks to biodiversity don’t increase gradually,” said Alex Pigot of Imperial College London, in the UK, who led the research.

Abrupt change

“Instead, as the climate warms, within a certain area most species will be able to cope for a while, before crossing a temperature threshold, when a large proportion of the species will suddenly face conditions they’ve never experienced before.

“It’s not a slippery slope, but a series of cliff edges, hitting different areas at different times.”

The finding – published in the journal Nature – should come as no great surprise to the world’s zoologists, botanists, ecologists, foresters, marine scientists and conservationists.

They have repeatedly warned that as global temperatures rise, and climate patterns become increasingly unstable, in response to ever-higher greenhouse gas emissions from power stations and car exhausts, and forest destruction, both individual species and even whole habitats could be exposed to loss and species extinction.

Such threats can be prefigured even in subtle changes in species behaviour. Within this month, Spanish ornithologists who have studied the nightingale Luscinia megarhynchos since 1995 report in the journal The Auk: Ornithological Advances that in two decades, as Spanish summers became hotter and more parched, the wings of each new generation of birds have become progressively shorter.

“Our findings highlight the urgent need for climate change mitigation, by immediately and drastically reducing emissions, which could help save thousands of species from extinction”

A shorter wingspan in proportion to body length creates potential survival problems for a species that breeds in Europe but prefers to fly to sub-Saharan Africa for the winter.

And across the Atlantic, another species, the American robin Turdus migratorius now takes wing 12 days earlier each spring in Mexico and the US to fly to its summer breeding grounds in Canada and Alaska.

The ornithologists report in the journal Environmental Research Letters that GPS tracking of 55 individual birds confirms that the bird may be timing its migration to the snow melt and the first arrival of insects in the high latitudes nearer the fast-warming Arctic.

So far, the planet on average has warmed around only 1°C above the long-term average for most of human history. But Dr Pigot and colleagues in the US and South Africa wanted to look at the big picture of potential change in species everywhere as global heating reaches 2°C – the upper limits that the world’s nations promised in a key international agreement reached in Paris in 2015 – and then goes on soaring.

So they took their species data, and mapped it onto a global grid divided into 100-km-square cells, and then fine-tuned the temperature predicted by climate scientists to see where species and their habitats would experience ever-rising heat beyond their comfort zone.

Unprecedented ocean heat

Any ecosystem is a network of interdependencies: insects pollinate flowers, animals disperse seed and prey upon pests and each other in an intricate set of arrangements that have evolved over tens of thousands of years in a particular pattern of temperature and precipitation. Any disturbance ripples through the entire habitat.

The scientists’ atlas of potential ecological disruption included isolated bits of the world such as the Cayman Islands in the Caribbean and the Gobi Desert in Mongolia as well as the Amazon basin and the forests and clearings in the Congo, and one of the world’s richest marine habitats, the so-called Coral Triangle bounded by the Philippines, Malaysia, Papua New Guinea and the islands of the Western Pacific.

They found that if warming could be contained to 2°C or less, only about one community in 50 would be faced with exposure to such disruption: they warn however that even this 2% includes some of the richest habitats on the planet.

They also warn that by 2030, the tropical oceans will start to experience temperature regimes that have no precedent in human history. The tropical forests could be at risk by 2050. Ominously, almost three-fourths of all the species to face unprecedented temperatures before the end of this century will all do so more or less at the same time.

“Our findings highlight the urgent need for climate change mitigation, by immediately and drastically reducing emissions, which could help save thousands of species from extinction,” Dr Pigot said. – Climate News Network

Rising global heat raises risks to the creatures and ecosystems that sustain human society. Collapse could be sudden and near-total.

LONDON, 14 April, 2020 – Worldwide, entire ecosystems could collapse as the planetary thermometer soars: rising global heat could see the Earth’s average temperature rise by 4°C (right now the world is heading for a rise of more than three degrees).

And then one in six of the complex communities of plants and animals in wetlands, grasslands, forests or oceans could drastically alter or fail.

That is because at such temperatures more than one in five of the creatures in that network of co-dependencies would in the same decade experience temperatures beyond their normal tolerance levels.

The prediction is based on data that pinpoint the geographical ranges of 30,652 birds, mammals, reptiles, amphibians, fish and plants, and climate data from 1850 to 2005.

“We found that climate change risks to biodiversity don’t increase gradually,” said Alex Pigot of Imperial College London, in the UK, who led the research.

Abrupt change

“Instead, as the climate warms, within a certain area most species will be able to cope for a while, before crossing a temperature threshold, when a large proportion of the species will suddenly face conditions they’ve never experienced before.

“It’s not a slippery slope, but a series of cliff edges, hitting different areas at different times.”

The finding – published in the journal Nature – should come as no great surprise to the world’s zoologists, botanists, ecologists, foresters, marine scientists and conservationists.

They have repeatedly warned that as global temperatures rise, and climate patterns become increasingly unstable, in response to ever-higher greenhouse gas emissions from power stations and car exhausts, and forest destruction, both individual species and even whole habitats could be exposed to loss and species extinction.

Such threats can be prefigured even in subtle changes in species behaviour. Within this month, Spanish ornithologists who have studied the nightingale Luscinia megarhynchos since 1995 report in the journal The Auk: Ornithological Advances that in two decades, as Spanish summers became hotter and more parched, the wings of each new generation of birds have become progressively shorter.

“Our findings highlight the urgent need for climate change mitigation, by immediately and drastically reducing emissions, which could help save thousands of species from extinction”

A shorter wingspan in proportion to body length creates potential survival problems for a species that breeds in Europe but prefers to fly to sub-Saharan Africa for the winter.

And across the Atlantic, another species, the American robin Turdus migratorius now takes wing 12 days earlier each spring in Mexico and the US to fly to its summer breeding grounds in Canada and Alaska.

The ornithologists report in the journal Environmental Research Letters that GPS tracking of 55 individual birds confirms that the bird may be timing its migration to the snow melt and the first arrival of insects in the high latitudes nearer the fast-warming Arctic.

So far, the planet on average has warmed around only 1°C above the long-term average for most of human history. But Dr Pigot and colleagues in the US and South Africa wanted to look at the big picture of potential change in species everywhere as global heating reaches 2°C – the upper limits that the world’s nations promised in a key international agreement reached in Paris in 2015 – and then goes on soaring.

So they took their species data, and mapped it onto a global grid divided into 100-km-square cells, and then fine-tuned the temperature predicted by climate scientists to see where species and their habitats would experience ever-rising heat beyond their comfort zone.

Unprecedented ocean heat

Any ecosystem is a network of interdependencies: insects pollinate flowers, animals disperse seed and prey upon pests and each other in an intricate set of arrangements that have evolved over tens of thousands of years in a particular pattern of temperature and precipitation. Any disturbance ripples through the entire habitat.

The scientists’ atlas of potential ecological disruption included isolated bits of the world such as the Cayman Islands in the Caribbean and the Gobi Desert in Mongolia as well as the Amazon basin and the forests and clearings in the Congo, and one of the world’s richest marine habitats, the so-called Coral Triangle bounded by the Philippines, Malaysia, Papua New Guinea and the islands of the Western Pacific.

They found that if warming could be contained to 2°C or less, only about one community in 50 would be faced with exposure to such disruption: they warn however that even this 2% includes some of the richest habitats on the planet.

They also warn that by 2030, the tropical oceans will start to experience temperature regimes that have no precedent in human history. The tropical forests could be at risk by 2050. Ominously, almost three-fourths of all the species to face unprecedented temperatures before the end of this century will all do so more or less at the same time.

“Our findings highlight the urgent need for climate change mitigation, by immediately and drastically reducing emissions, which could help save thousands of species from extinction,” Dr Pigot said. – Climate News Network

Fossil fuels add to world’s marine dead zones

Air pollution from burning fossil fuels is adding to fertiliser run-off and sewage to kill marine life in global dead zones.

LONDON, 6 April, 2020 − Cutting out coal-burning and other sources of nitrogen oxides (NOx) from heavy industry, electricity production and traffic will reduce the size of the world’s dead zones along coasts where all fish life is vanishing because of a lack of oxygen.

Researchers in Hong Kong report in the journal Environmental Science & Technology that cutting fossil fuel use in China would benefit not only the climate but also the fisheries along all the country’s coasts.

The finding is significant because many countries concerned about the loss of their coastal and lake fisheries caused by dead zones have been concentrating only on reducing agricultural fertiliser run-off from fields and sewage discharges, which are known to load the rivers with nutrients.

When the nutrients reach lakes or the open sea they feed algae, which rapidly grow into huge green masses. When these so-called algal blooms die they sink to the bottom and decompose, using up nearly all the oxygen in the water.

This process, known as eutrophication, leads to hypoxia, a level of oxygen that is too low for most organisms to survive. Fish usually swim away to healthier waters, but life forms which cannot easily move simply die.

“I hope our study brings more attention to the potential benefit of reducing fossil fuel burning on human and ecosystem health, but also on local economic activities like fisheries”

NOx emissions from fossil fuel burning and fertiliser manufacture lead to the formation of ground-level ozone, smog and acid rain, and contribute to global warming through the greenhouse effect.

What the new research shows is that while fertiliser and sewage are very important in creating dead zones, the aerial input of NOx makes a bad situation far worse.

The report’s lead author, Yu Yan Yau, an MPhil student at the University of Hong Kong’s Swire Institute of Marine Science (SWIMS), and her colleagues studied the South China, East China, Yellow and Bohai Seas.

They found that the atmospheric deposition of nutrients from fossil fuel burning on the mainland increased the amount of organic matter decomposing at the bottom of the sea by 15%, and increased the dead zones by 5%. The South China Sea was the most sensitive to fossil fuel burning.

Investigation needed

The good news in their research was that cutting this burning would considerably reduce the size of the dead zones.

Yu Yan Yau said: “I hope our study brings more attention to the potential benefit of reducing fossil fuel burning on human and ecosystem health, but also on local economic activities like fisheries, which are severely affected by hypoxia.”

Her supervisor, Dr Benoit Thibodeau, added: “Low levels of oxygen are observed in many coastal seas around the world and it is important to find better ways to tackle this problem.

“While we understand that sewage and nutrient input from the Pearl River drive most of the hypoxia in the Greater Bay Area, we observe low levels of oxygen in regions that are not directly under the influence of these sources. Thus it is important to investigate the impact of atmospheric deposition more locally.”

These findings will be important to many countries that are trying to rescue their coastal fisheries from dead zones. There are about 400 of these globally, including parts of Europe’s Baltic Sea.

Industrial impact

The largest is in the Arabian Sea, covering about 63,000 square miles, and the second largest a vast area in the Gulf of Mexico next to the Mississippi Delta, where a dead zone devoid of marine life develops every summer.

Every year winter rains wash fertiliser from fields in the US corn belt into the river. Combined with sewage overflows, this creates a huge quantity of nutrients that sweep down the river into the sea.

Depending on the size of the winter floods, scientists try to predict the extent of the resultant dead zone. However, the banks of the lower river are also crowded with heavy industrial sites, many burning large quantities of fossil fuels and creating large amounts of NOx, something that previously has not been taken into account.

If the Hong Kong research is correct, then cutting the pollution from these industries will also reduce the size of the Mississippi’s dead zone. − Climate News Network

Air pollution from burning fossil fuels is adding to fertiliser run-off and sewage to kill marine life in global dead zones.

LONDON, 6 April, 2020 − Cutting out coal-burning and other sources of nitrogen oxides (NOx) from heavy industry, electricity production and traffic will reduce the size of the world’s dead zones along coasts where all fish life is vanishing because of a lack of oxygen.

Researchers in Hong Kong report in the journal Environmental Science & Technology that cutting fossil fuel use in China would benefit not only the climate but also the fisheries along all the country’s coasts.

The finding is significant because many countries concerned about the loss of their coastal and lake fisheries caused by dead zones have been concentrating only on reducing agricultural fertiliser run-off from fields and sewage discharges, which are known to load the rivers with nutrients.

When the nutrients reach lakes or the open sea they feed algae, which rapidly grow into huge green masses. When these so-called algal blooms die they sink to the bottom and decompose, using up nearly all the oxygen in the water.

This process, known as eutrophication, leads to hypoxia, a level of oxygen that is too low for most organisms to survive. Fish usually swim away to healthier waters, but life forms which cannot easily move simply die.

“I hope our study brings more attention to the potential benefit of reducing fossil fuel burning on human and ecosystem health, but also on local economic activities like fisheries”

NOx emissions from fossil fuel burning and fertiliser manufacture lead to the formation of ground-level ozone, smog and acid rain, and contribute to global warming through the greenhouse effect.

What the new research shows is that while fertiliser and sewage are very important in creating dead zones, the aerial input of NOx makes a bad situation far worse.

The report’s lead author, Yu Yan Yau, an MPhil student at the University of Hong Kong’s Swire Institute of Marine Science (SWIMS), and her colleagues studied the South China, East China, Yellow and Bohai Seas.

They found that the atmospheric deposition of nutrients from fossil fuel burning on the mainland increased the amount of organic matter decomposing at the bottom of the sea by 15%, and increased the dead zones by 5%. The South China Sea was the most sensitive to fossil fuel burning.

Investigation needed

The good news in their research was that cutting this burning would considerably reduce the size of the dead zones.

Yu Yan Yau said: “I hope our study brings more attention to the potential benefit of reducing fossil fuel burning on human and ecosystem health, but also on local economic activities like fisheries, which are severely affected by hypoxia.”

Her supervisor, Dr Benoit Thibodeau, added: “Low levels of oxygen are observed in many coastal seas around the world and it is important to find better ways to tackle this problem.

“While we understand that sewage and nutrient input from the Pearl River drive most of the hypoxia in the Greater Bay Area, we observe low levels of oxygen in regions that are not directly under the influence of these sources. Thus it is important to investigate the impact of atmospheric deposition more locally.”

These findings will be important to many countries that are trying to rescue their coastal fisheries from dead zones. There are about 400 of these globally, including parts of Europe’s Baltic Sea.

Industrial impact

The largest is in the Arabian Sea, covering about 63,000 square miles, and the second largest a vast area in the Gulf of Mexico next to the Mississippi Delta, where a dead zone devoid of marine life develops every summer.

Every year winter rains wash fertiliser from fields in the US corn belt into the river. Combined with sewage overflows, this creates a huge quantity of nutrients that sweep down the river into the sea.

Depending on the size of the winter floods, scientists try to predict the extent of the resultant dead zone. However, the banks of the lower river are also crowded with heavy industrial sites, many burning large quantities of fossil fuels and creating large amounts of NOx, something that previously has not been taken into account.

If the Hong Kong research is correct, then cutting the pollution from these industries will also reduce the size of the Mississippi’s dead zone. − Climate News Network

Northern Europe’s warm water flow may falter

Global heating can stop the flow of Europe’s warm water from the tropics. Happening often during the Ice Ages, it could soon recur.

LONDON, 1 April, 2020 – Oceanographers have confirmed once again that global heating could slow or shut down the flow of currents such as the Gulf Stream, ending northern Europe’s warm water supply with an unexpected and prolonged cold snap.

This time the confidence is based neither on ocean measurements made now, nor complex computer simulations of the future. There is fresh evidence from the sea floor that such an ocean shutdown happened many times in the last half a million years of Ice Ages.

The Gulf Stream is part of a much larger flow of water called the Atlantic Meridional Overturning Circulation, an ocean recycling system that both nourishes marine life and moderates the climate in two hemispheres.

For the last 10,000 years of human history, tropical water has flowed north from the Caribbean and equatorial regions and washed the shores of Europe as far north as Norway, bringing equatorial heat to soften the impact of European winters.

A former UK chief scientist once calculated that the Gulf Stream delivered the warmth of 27,000 power stations and kept Britain about 5°C warmer than its citizens had any right to expect, given the latitude at which they lived.

“These findings suggest that our climate system, which depends greatly on deep ocean circulation, is critically poised near a tipping point for abrupt disruptions”

But as that stretch of the Gulf Stream known to oceanographers as the North Atlantic drift current reaches the Greenland Sea it becomes increasingly colder and saltier and thus more dense, and sinks to the ocean floor, loaded with dissolved atmospheric carbon dioxide and oxygen, to become a southward flow called the North Atlantic Deepwater formation.

And it also mingles with fresh water melting each summer from the Greenland ice sheet. But as the rate of Arctic melting accelerates, more fresh water will plunge into the same sea, with an increasing probability that it will disrupt the ocean cycle, turn off the flow of warm tropical water, and plunge Europe into a prolonged cold spell.

In its most dramatic form, this hypothesis was the basis for a 2004 Hollywood disaster movie called The Day After Tomorrow. Climate scientists are fairly sure that such an event would not mean the sudden advance of glacial ice over much of Europe and North America. But they have repeatedly identified evidence that the flow of the northward current is beginning to weaken.

And the journal Science now carries additional evidence that the ocean circulation was repeatedly interrupted for periods of a century or more during the warm spells or interglacials that have happened during the last 450,000 years.

Shells’ signatures

The signature of ocean change is there in the tiny sea shells from marine creatures called foraminifera that rain down onto the ocean floor to form annual layers of silent testimony to past climates.

When the mix of carbon isotope ratios preserved in them is high, that is a sign that the Atlantic circulation was once vigorous. When it is low, then this overturning circulation is feeble, or has stopped altogether.

The signal from the deep ocean is that when they happen, these disruptions seem to happen very swiftly, and to linger for 100 years or more. And, the scientists say, these interruptions in the flow of the ocean – and with it, the transport of heat from the tropics – happen more easily than previously appreciated, and they occurred in past climate conditions similar to those the world may soon face.

“These findings suggest that our climate system, which depends greatly on deep ocean circulation, is critically poised near a tipping point for abrupt disruptions,” said Yair Rosenthal of Rutgers University in the US, one of the authors.

“Although the disruptions in circulation and possible coolings may be relatively short-lived – lasting maybe a century or more – the consequences might be large.” – Climate News Network

Global heating can stop the flow of Europe’s warm water from the tropics. Happening often during the Ice Ages, it could soon recur.

LONDON, 1 April, 2020 – Oceanographers have confirmed once again that global heating could slow or shut down the flow of currents such as the Gulf Stream, ending northern Europe’s warm water supply with an unexpected and prolonged cold snap.

This time the confidence is based neither on ocean measurements made now, nor complex computer simulations of the future. There is fresh evidence from the sea floor that such an ocean shutdown happened many times in the last half a million years of Ice Ages.

The Gulf Stream is part of a much larger flow of water called the Atlantic Meridional Overturning Circulation, an ocean recycling system that both nourishes marine life and moderates the climate in two hemispheres.

For the last 10,000 years of human history, tropical water has flowed north from the Caribbean and equatorial regions and washed the shores of Europe as far north as Norway, bringing equatorial heat to soften the impact of European winters.

A former UK chief scientist once calculated that the Gulf Stream delivered the warmth of 27,000 power stations and kept Britain about 5°C warmer than its citizens had any right to expect, given the latitude at which they lived.

“These findings suggest that our climate system, which depends greatly on deep ocean circulation, is critically poised near a tipping point for abrupt disruptions”

But as that stretch of the Gulf Stream known to oceanographers as the North Atlantic drift current reaches the Greenland Sea it becomes increasingly colder and saltier and thus more dense, and sinks to the ocean floor, loaded with dissolved atmospheric carbon dioxide and oxygen, to become a southward flow called the North Atlantic Deepwater formation.

And it also mingles with fresh water melting each summer from the Greenland ice sheet. But as the rate of Arctic melting accelerates, more fresh water will plunge into the same sea, with an increasing probability that it will disrupt the ocean cycle, turn off the flow of warm tropical water, and plunge Europe into a prolonged cold spell.

In its most dramatic form, this hypothesis was the basis for a 2004 Hollywood disaster movie called The Day After Tomorrow. Climate scientists are fairly sure that such an event would not mean the sudden advance of glacial ice over much of Europe and North America. But they have repeatedly identified evidence that the flow of the northward current is beginning to weaken.

And the journal Science now carries additional evidence that the ocean circulation was repeatedly interrupted for periods of a century or more during the warm spells or interglacials that have happened during the last 450,000 years.

Shells’ signatures

The signature of ocean change is there in the tiny sea shells from marine creatures called foraminifera that rain down onto the ocean floor to form annual layers of silent testimony to past climates.

When the mix of carbon isotope ratios preserved in them is high, that is a sign that the Atlantic circulation was once vigorous. When it is low, then this overturning circulation is feeble, or has stopped altogether.

The signal from the deep ocean is that when they happen, these disruptions seem to happen very swiftly, and to linger for 100 years or more. And, the scientists say, these interruptions in the flow of the ocean – and with it, the transport of heat from the tropics – happen more easily than previously appreciated, and they occurred in past climate conditions similar to those the world may soon face.

“These findings suggest that our climate system, which depends greatly on deep ocean circulation, is critically poised near a tipping point for abrupt disruptions,” said Yair Rosenthal of Rutgers University in the US, one of the authors.

“Although the disruptions in circulation and possible coolings may be relatively short-lived – lasting maybe a century or more – the consequences might be large.” – Climate News Network

Blue energy revolution comes of age

With green energy from wind and solar out-competing fossil fuels, governments now hope for another boost − blue energy from the oceans.

LONDON, 31 March, 2020 − The amount of energy generated by tides and waves in the last decade has increased 10-fold. Now governments around the world are planning to scale up these ventures to tap into the oceans’ vast store of blue energy.

Although in 2019 the total amount of energy produced by “blue power” would have been enough to provide electricity to only one city the size of Paris, even that was a vast increase on the tiny experiments being carried out 10 years earlier.

Now countries across the world with access to the sea are beginning to exploit all sorts of new technologies and intending to scale them up to bolster their attempts to go carbon-neutral.

Blue energy takes many forms. One of the most difficult technically is harnessing the energy of waves with devices that produce electricity. After several false starts many successful prototypes are now being trialled for commercial use. Other experiments exploit the tidal range – using the power of rapidly rising and falling tidal streams to push water through turbines.

The most commercially successful strategies so far use underwater turbines, similar to wind turbines, to exploit the tidal currents in coastal regions.

More ambitious but along the same lines are attempts to capture the energy from the immense ocean currents that move vast quantities of water round the planet.

“Our latest report underlines the considerable international support for the marine renewable sector. The start of this new decade carries considerable promise for ocean energy”

Also included in blue energy is ocean thermal energy conversion, which exploits the temperature differences between solar energy stored as heat in the upper ocean layers and colder seawater, generally at a depth below 1000 metres.

A variation on this is to use salinity gradients, the difference between the salt content of the sea and fresh water entering from a large river system. Some of these schemes are being used to produce fresh drinking water for dry regions rather than electricity.

The potential from all these energy sources is so great that an organisation called Ocean Energy Systems (OES), an offshoot of the International Energy Agency, is pooling all the research in a bid to achieve large-scale deployment.

There are now 24 countries in the OES, including China, India, the US, most European nations with a coastline, Japan, Australia and South Africa. Most of them have already deployed some blue energy schemes and are hoping to scale them up to full commercial use in the next decade.

As with wind and solar when they were being widely developed ten years ago, energy from the oceans is currently more expensive than fossil fuels. But as the technologies are refined the costs are coming down.

Profiting already

Already China has encouraged tidal stream energy by offering a feed-in tariff three times the price of fossil fuels, similar to the rate used in many countries to launch solar and wind power. One Chinese company is already finding this incentive enough to feed power into the grid and make a profit.

Among the leading countries developing these technologies are Canada and the United Kingdom, the two countries with the highest tides in the world. Canada has a number of tidal energy schemes on its Atlantic coast in Nova Scotia, with several competing companies testing different prototypes.

Scotland, which has enormous potential because of its many islands and tidal currents, has the largest tidal array of underwater turbines in the world. The turbine output has exceeded expectations, and the MeyGen company is planning to vastly increase the number of installations.

But this is only one of more than 20 projects in the UK, some still in the research and development stage, but many already being scaled up for deployment at special testing grounds in Scotland’s Orkney islands and the West of England.

OES chairman Henry Jeffrey, from the University of Edinburgh, said the group’s new annual report communicates the sizeable global effort to identify commercialisation pathways for ocean energy technologies.

Both Canada and the US can now see big potential, and political leaders across Europe have identified ocean energy as an essential component in meeting decarbonisation targets, fostering economic growth and creating future employment opportunities.

Lower costs essential

“Our latest report underlines the considerable international support for the marine renewable sector as leading global powers attempt to rebalance energy usage and limit global warming. The start of this new decade carries considerable promise for ocean energy,” he said.

However, Jeffrey warned that while the sector continued to take huge strides forward, there were several challenges ahead “centred around affordability, reliability, installability, operability, funding availability, capacity building and standardisation.

“In particular, significant cost reductions are required for ocean energy technologies to compete with other low-carbon technologies.”

Currently the cost of wind power, taking into account construction costs over the turbines’ lifetime, is being quoted as around €0.8-10 (one eighth to one tenth of a Euro, about £0.07-9 or US$0.9-11) per kilowatt hour, but this is still going down.

The European target is to get tidal stream energy down to €0.10 by 2030 and wave power down to €0.15, which would also make them competitive with fossil fuels if gas and coal were obliged to pay for capturing and storing the carbon dioxide they produce. − Climate News Network

With green energy from wind and solar out-competing fossil fuels, governments now hope for another boost − blue energy from the oceans.

LONDON, 31 March, 2020 − The amount of energy generated by tides and waves in the last decade has increased 10-fold. Now governments around the world are planning to scale up these ventures to tap into the oceans’ vast store of blue energy.

Although in 2019 the total amount of energy produced by “blue power” would have been enough to provide electricity to only one city the size of Paris, even that was a vast increase on the tiny experiments being carried out 10 years earlier.

Now countries across the world with access to the sea are beginning to exploit all sorts of new technologies and intending to scale them up to bolster their attempts to go carbon-neutral.

Blue energy takes many forms. One of the most difficult technically is harnessing the energy of waves with devices that produce electricity. After several false starts many successful prototypes are now being trialled for commercial use. Other experiments exploit the tidal range – using the power of rapidly rising and falling tidal streams to push water through turbines.

The most commercially successful strategies so far use underwater turbines, similar to wind turbines, to exploit the tidal currents in coastal regions.

More ambitious but along the same lines are attempts to capture the energy from the immense ocean currents that move vast quantities of water round the planet.

“Our latest report underlines the considerable international support for the marine renewable sector. The start of this new decade carries considerable promise for ocean energy”

Also included in blue energy is ocean thermal energy conversion, which exploits the temperature differences between solar energy stored as heat in the upper ocean layers and colder seawater, generally at a depth below 1000 metres.

A variation on this is to use salinity gradients, the difference between the salt content of the sea and fresh water entering from a large river system. Some of these schemes are being used to produce fresh drinking water for dry regions rather than electricity.

The potential from all these energy sources is so great that an organisation called Ocean Energy Systems (OES), an offshoot of the International Energy Agency, is pooling all the research in a bid to achieve large-scale deployment.

There are now 24 countries in the OES, including China, India, the US, most European nations with a coastline, Japan, Australia and South Africa. Most of them have already deployed some blue energy schemes and are hoping to scale them up to full commercial use in the next decade.

As with wind and solar when they were being widely developed ten years ago, energy from the oceans is currently more expensive than fossil fuels. But as the technologies are refined the costs are coming down.

Profiting already

Already China has encouraged tidal stream energy by offering a feed-in tariff three times the price of fossil fuels, similar to the rate used in many countries to launch solar and wind power. One Chinese company is already finding this incentive enough to feed power into the grid and make a profit.

Among the leading countries developing these technologies are Canada and the United Kingdom, the two countries with the highest tides in the world. Canada has a number of tidal energy schemes on its Atlantic coast in Nova Scotia, with several competing companies testing different prototypes.

Scotland, which has enormous potential because of its many islands and tidal currents, has the largest tidal array of underwater turbines in the world. The turbine output has exceeded expectations, and the MeyGen company is planning to vastly increase the number of installations.

But this is only one of more than 20 projects in the UK, some still in the research and development stage, but many already being scaled up for deployment at special testing grounds in Scotland’s Orkney islands and the West of England.

OES chairman Henry Jeffrey, from the University of Edinburgh, said the group’s new annual report communicates the sizeable global effort to identify commercialisation pathways for ocean energy technologies.

Both Canada and the US can now see big potential, and political leaders across Europe have identified ocean energy as an essential component in meeting decarbonisation targets, fostering economic growth and creating future employment opportunities.

Lower costs essential

“Our latest report underlines the considerable international support for the marine renewable sector as leading global powers attempt to rebalance energy usage and limit global warming. The start of this new decade carries considerable promise for ocean energy,” he said.

However, Jeffrey warned that while the sector continued to take huge strides forward, there were several challenges ahead “centred around affordability, reliability, installability, operability, funding availability, capacity building and standardisation.

“In particular, significant cost reductions are required for ocean energy technologies to compete with other low-carbon technologies.”

Currently the cost of wind power, taking into account construction costs over the turbines’ lifetime, is being quoted as around €0.8-10 (one eighth to one tenth of a Euro, about £0.07-9 or US$0.9-11) per kilowatt hour, but this is still going down.

The European target is to get tidal stream energy down to €0.10 by 2030 and wave power down to €0.15, which would also make them competitive with fossil fuels if gas and coal were obliged to pay for capturing and storing the carbon dioxide they produce. − Climate News Network

Polar ice melt raises sea level dangers

polar ice

Greenland’s polar ice is now melting far faster than 30 years ago, Antarctic ice is retreating at an accelerating rate, and sea levels are creeping up.

LONDON, 19 March, 2020 – Greenland and Antarctica, the two greatest stores of frozen water on the planet, are now losing polar ice at a rate at least six times faster than they were at the close of the last century.

The fact that polar ice is melting ever faster has been clear for a decade, but the latest research is authoritative.

To establish the rate of loss, 89 polar scientists from 50 of the world’s great research institutions looked at data from 26 separate surveys between 1992 and 2018, along with information from 11 different satellite missions.

Gloomiest forecasts

And the finding is in line with the worst-case scenarios considered by the Intergovernmental Panel on Climate Change (IPCC). If this rate of increase continues, sea levels at the close of this century will be at least 17 centimetres higher than the gloomiest official forecasts so far.

Between 1992 and 2017, the global sea level rose by 17.8 millimetres, as 6.4 trillion tonnes of polar ice turned to water and trickled into the oceans – 10.6 mm from Greenland and 7.2 mm from Antarctica.

In the last decade of the last century, the northern and southern icecaps dwindled at the rate of 81 billion tonnes a year. In the last decade, this had risen to 475 billion tonnes a year. This means that a third of all sea level rise is now caused by the loss of polar ice.

The most recent assessment by the IPCC is that, by 2100, sea levels will have risen by 53 cms, putting 360 million people who live at sea level at some risk.

“This would mean 400 million people at risk of annual coastal flooding by 2100”

But the latest finding from the Ice Sheet Mass Balance Inter-comparison Exercise (IMBIE) scientists is that seas will rise even higher, and even more people will have to move.

“Every centimetre of sea level rise leads to coastal flooding and coastal erosion, disrupting people’s lives around the planet,” said Andrew Shepherd, professor of Earth observation at the University of Leeds, UK, as he and colleagues published their findings of Greenland losses in Nature journal.

“If Antarctica and Greenland continue to track the worst-case climate warning scenario, they will cause an extra 17 cms of sea level rise by the end of the century.

“This would mean 400 million people at risk of annual coastal flooding by 2100. These are not unlikely events with small impacts; they are already under way and will be devastating for coastal communities.”

Global picture

Professor Shepherd and his IMBIE colleagues established almost two years ago that Antarctica was losing ice at an ever-accelerating rate, but the Greenland survey completes the global picture.

And it remains a picture in which the Arctic seems to be warming at an accelerating rate and sea levels seem to be rising ever faster.

This is not just because the polar ice caps are melting, but also because, almost everywhere, mountain glaciers are in retreat, and the oceans are expanding as sea temperatures rise in response to the steady warming of the planetary atmosphere. – Climate News Network

Greenland’s polar ice is now melting far faster than 30 years ago, Antarctic ice is retreating at an accelerating rate, and sea levels are creeping up.

LONDON, 19 March, 2020 – Greenland and Antarctica, the two greatest stores of frozen water on the planet, are now losing polar ice at a rate at least six times faster than they were at the close of the last century.

The fact that polar ice is melting ever faster has been clear for a decade, but the latest research is authoritative.

To establish the rate of loss, 89 polar scientists from 50 of the world’s great research institutions looked at data from 26 separate surveys between 1992 and 2018, along with information from 11 different satellite missions.

Gloomiest forecasts

And the finding is in line with the worst-case scenarios considered by the Intergovernmental Panel on Climate Change (IPCC). If this rate of increase continues, sea levels at the close of this century will be at least 17 centimetres higher than the gloomiest official forecasts so far.

Between 1992 and 2017, the global sea level rose by 17.8 millimetres, as 6.4 trillion tonnes of polar ice turned to water and trickled into the oceans – 10.6 mm from Greenland and 7.2 mm from Antarctica.

In the last decade of the last century, the northern and southern icecaps dwindled at the rate of 81 billion tonnes a year. In the last decade, this had risen to 475 billion tonnes a year. This means that a third of all sea level rise is now caused by the loss of polar ice.

The most recent assessment by the IPCC is that, by 2100, sea levels will have risen by 53 cms, putting 360 million people who live at sea level at some risk.

“This would mean 400 million people at risk of annual coastal flooding by 2100”

But the latest finding from the Ice Sheet Mass Balance Inter-comparison Exercise (IMBIE) scientists is that seas will rise even higher, and even more people will have to move.

“Every centimetre of sea level rise leads to coastal flooding and coastal erosion, disrupting people’s lives around the planet,” said Andrew Shepherd, professor of Earth observation at the University of Leeds, UK, as he and colleagues published their findings of Greenland losses in Nature journal.

“If Antarctica and Greenland continue to track the worst-case climate warning scenario, they will cause an extra 17 cms of sea level rise by the end of the century.

“This would mean 400 million people at risk of annual coastal flooding by 2100. These are not unlikely events with small impacts; they are already under way and will be devastating for coastal communities.”

Global picture

Professor Shepherd and his IMBIE colleagues established almost two years ago that Antarctica was losing ice at an ever-accelerating rate, but the Greenland survey completes the global picture.

And it remains a picture in which the Arctic seems to be warming at an accelerating rate and sea levels seem to be rising ever faster.

This is not just because the polar ice caps are melting, but also because, almost everywhere, mountain glaciers are in retreat, and the oceans are expanding as sea temperatures rise in response to the steady warming of the planetary atmosphere. – Climate News Network

Sandy beaches may succumb to rising seas

Ever higher seas are already eroding shorelines and flooding coasts. Soon the waves could wash away half the world’s sandy beaches.

LONDON, 5 March, 2020 – Right now, around a third of the world’s coastline is made up of sandy beaches and dunes which slope gently and softly to the sea. By the end of the century, these could make up only one-sixth of the frontier between land and ocean. Sea level rise driven by global heating could sweep half of them away.

Beaches are nature’s buffers between eroding land and tempestuous sea: they protect the coast, they provide a unique habitat for wildlife, and they have become powerful socio-economic resources.

But the paradise for surfers around sunlit Australia is almost certain to be diminished in the coming climate crisis as the waves lap ever higher, storm surges sweep away vast volumes of sand, and seas flood low-lying coasts. And – according to new European research in the journal Nature Climate Change – what is true for Australia is true for much of the rest of the world.

How much beach is lost will depend on how nations respond to the challenge of climate change. But in the worst-case scenario, Australia and Canada could each say goodbye to nearly 15,000 kilometres of sandy shore by 2100. Chile could lose more than 6,000 km, Mexico, China and the US more than 5,000 km, Russia more than 4,000 km and Argentina more than 3,000 km.

“Much of the world’s coast is already eroding, which could get worse with sea level rise”

And that’s the outlook for countries with vast coastlines. Some could fare even worse. Guinea-Bissau and The Gambia in West Africa, for instance, could lose 60% of their beaches.

The European scientists looked at more than 30 years of satellite data on coastal change – from 1984 to 2015 – and 82 years of climate and sea level predictions from a range of climate models. They also simulated 100 million storm events.

There is plenty of evidence that the world’s seas are responding to climate change; that sea levels are rising in response to warmer atmospheric temperatures driven by profligate combustion of fossil fuels; and that coastal flooding is likely to become more extreme.

But the detailed questions remain: how exactly will ever-higher tides exact their toll of the wetlands, mangrove forests, estuaries, cliff faces, rocky coasts, storm beaches and dunes that serve as a barrier between the maritime cities and towns of the world, and the saltwater? The researchers found that even in the more hopeful scenarios, there would be considerable losses.

UK backs study

But if nations delivered on the promise made in Paris in 2015 – a promise that still has to be backed up by urgent action on a global scale – to contain global heating to “well below” a maximum of 2°C by 2100, then perhaps 40% of the projected erosion of beaches could be halted.

Beaches are natural features of tidal landscapes: sand swept away by violent storms is eventually replaced by silt carried down the rivers to the coasts. The shoreline has always changed. But change is accelerating. Scientists in the UK have endorsed the European study.

“Much of the world’s coast is already eroding, which could get worse with sea level rise,” said Sally Brown, of Bournemouth University. Bournemouth is a famous British seaside resort.

“Building defences helps maintain coastline position, but defences are known to reduce beach width or depth over multiple decades. Responding to sea level rise means looking strategically at how and where we defend coasts today, which may mean protecting only limited parts of the coast.” – Climate News Network

Ever higher seas are already eroding shorelines and flooding coasts. Soon the waves could wash away half the world’s sandy beaches.

LONDON, 5 March, 2020 – Right now, around a third of the world’s coastline is made up of sandy beaches and dunes which slope gently and softly to the sea. By the end of the century, these could make up only one-sixth of the frontier between land and ocean. Sea level rise driven by global heating could sweep half of them away.

Beaches are nature’s buffers between eroding land and tempestuous sea: they protect the coast, they provide a unique habitat for wildlife, and they have become powerful socio-economic resources.

But the paradise for surfers around sunlit Australia is almost certain to be diminished in the coming climate crisis as the waves lap ever higher, storm surges sweep away vast volumes of sand, and seas flood low-lying coasts. And – according to new European research in the journal Nature Climate Change – what is true for Australia is true for much of the rest of the world.

How much beach is lost will depend on how nations respond to the challenge of climate change. But in the worst-case scenario, Australia and Canada could each say goodbye to nearly 15,000 kilometres of sandy shore by 2100. Chile could lose more than 6,000 km, Mexico, China and the US more than 5,000 km, Russia more than 4,000 km and Argentina more than 3,000 km.

“Much of the world’s coast is already eroding, which could get worse with sea level rise”

And that’s the outlook for countries with vast coastlines. Some could fare even worse. Guinea-Bissau and The Gambia in West Africa, for instance, could lose 60% of their beaches.

The European scientists looked at more than 30 years of satellite data on coastal change – from 1984 to 2015 – and 82 years of climate and sea level predictions from a range of climate models. They also simulated 100 million storm events.

There is plenty of evidence that the world’s seas are responding to climate change; that sea levels are rising in response to warmer atmospheric temperatures driven by profligate combustion of fossil fuels; and that coastal flooding is likely to become more extreme.

But the detailed questions remain: how exactly will ever-higher tides exact their toll of the wetlands, mangrove forests, estuaries, cliff faces, rocky coasts, storm beaches and dunes that serve as a barrier between the maritime cities and towns of the world, and the saltwater? The researchers found that even in the more hopeful scenarios, there would be considerable losses.

UK backs study

But if nations delivered on the promise made in Paris in 2015 – a promise that still has to be backed up by urgent action on a global scale – to contain global heating to “well below” a maximum of 2°C by 2100, then perhaps 40% of the projected erosion of beaches could be halted.

Beaches are natural features of tidal landscapes: sand swept away by violent storms is eventually replaced by silt carried down the rivers to the coasts. The shoreline has always changed. But change is accelerating. Scientists in the UK have endorsed the European study.

“Much of the world’s coast is already eroding, which could get worse with sea level rise,” said Sally Brown, of Bournemouth University. Bournemouth is a famous British seaside resort.

“Building defences helps maintain coastline position, but defences are known to reduce beach width or depth over multiple decades. Responding to sea level rise means looking strategically at how and where we defend coasts today, which may mean protecting only limited parts of the coast.” – Climate News Network

North Sea dams could save Europe’s coasts

There is a way to stop Europe’s coastal cities from vanishing below the waves – enclose the North Sea. But there’s a simpler solution.

LONDON, 4 March, 2020 − Two European scientists have proposed the ultimate flood barrier: they want to dam the North Sea and the English Channel with more than 600 kilometres (373 miles) of sea wall.

This would protect 15 nations in western Europe against the ravages of what could one day be 10 metres (33 feet) of sea level rise. It would ultimately turn the North Sea into a freshwater lake and, at up to €500 billion (£435 bn) or more, represent the single most costly piece of engineering ever.

But, the pair reason, to do nothing could cost the people of Europe perhaps 10 times as much as coasts eroded, the sea overwhelmed the Low Countries, reshaped the contours of a continent and forced 25 million people to move inland.

In their paper in the Bulletin of the American Meteorological SocietySjoerd Groeskamp of the Royal Netherlands Institute for Sea Research and Joakim Kjellsson of Geomar, the Helmholtz oceanographic research centre in Kiel, Germany, concede that what they propose “may seem an overwhelming and unrealistic solution at first.”

But compared with the cost of inaction, or the cost of managed retreat from the coastline that would displace millions, it could be the cheapest option. “It might be impossible to truly fathom the magnitude of the threat that global-mean sea level rise poses,” they warn.

Least bad option

Global average temperatures have risen by 1°C and sea levels by 21 cms (8 inches) since 1880. Sea level rise lags behind atmospheric warming, but the guess is that every degree Celsius in the air will be followed eventually by 2.3 metres (7.5 feet) of higher seas.

By 2100, temperatures could have risen more than 3°C and sea levels by up to 1.5 metres (5 feet). If nations carry on burning fossil fuels the icecaps will melt inexorably, and by 2500 seas could have risen by 10 metres.

“The best solution will always be the treatment of the cause: human-caused climate change,” they write. However, if nations do not act to control the greenhouse gas emissions and forest destruction that cause global heating, and ever higher tides, then solutions such as the North European Enclosure Dam, known for short as NEED, are the only option.

The two researchers propose a barrier, a dike of sloping sides 50 metres wide across the North Sea from Bergen in Norway to the north-east tip of Scotland, via the Shetland and Orkney Islands.

This would be 475 kms (295 miles) long, with an average depth of 127 metres (417 feet), but would have to cross a trench more than 300 metres (985 feet) deep. To withstand continued sea level rise beyond 2500, it would need to be 20 metres or more above the Atlantic waves.

“This dam is mainly a call to do something about climate change now. If we do nothing, then this extreme dam might just be the only solution”

The 160 kms (100 miles) of sea defence from south-west England to the westernmost point of France would be a little less problematic: sea depths are hardly more than 100 metres (330 feet).

But the engineers would also have to factor in the 40,000 cubic metres of river water that would discharge into this enclosed basin every second. This would mean the same volume would need pumping continuously into the Atlantic on the far side of the dikes.

Since the barrier would enclose a number of the world’s great shipping ports, there would have to be sluice gates to let the big ships through, or alternatively new ports on the ocean side of the barriers.

The very nature of the enclosed North Sea would begin to change. Within a decade or two, it would start to turn into a freshwater lake: it would be the end of centuries of a fishing industry.

It could – the scientists admit their calculations are of the “back of an envelope” variety – be done. They scaled up the costs of the world’s largest dikes so far in the Netherlands and South Korea, to calculate the 51 billion tonnes of sand needed for the project. This is about what the world uses every year in construction.

Technology tested

They note that fixed seabed oil platforms have been constructed to a depth of 500 metres (1,640 feet), so engineers already know how to do such things. Pumps of the scale required to handle the incoming river discharges are already in use, but they would be needed in their hundreds.

And although the cost would reach somewhere between €250-550 bn (£220-480 bn), this − spread over the 20 years the project would take − would represent only at most 0.32% of the gross domestic product of the UK, Netherlands, Germany, Belgium and Denmark combined: the five nations with most to lose from the rising tides.

It would, the authors argue, cost just the Netherlands – which already has 3,600 km (2,240 miles) of flood protection − a third of that sum to defend against sea level rises of only 1.5 metres. The good news is that, if such a project worked for western Europe, then the same techniques could enclose the Irish Sea, the Mediterranean, the Red Sea and the Persian Gulf.

“This dam makes it almost tangible what the consequences of continued sea level rise will be; a rise of 10 metres by the year 2500 according to the bleakest scenarios,” said Dr Groeskamp.

“This dam is therefore mainly a call to do something about climate change now. If we do nothing, then this extreme dam might just be the only solution.” − Climate News Network

There is a way to stop Europe’s coastal cities from vanishing below the waves – enclose the North Sea. But there’s a simpler solution.

LONDON, 4 March, 2020 − Two European scientists have proposed the ultimate flood barrier: they want to dam the North Sea and the English Channel with more than 600 kilometres (373 miles) of sea wall.

This would protect 15 nations in western Europe against the ravages of what could one day be 10 metres (33 feet) of sea level rise. It would ultimately turn the North Sea into a freshwater lake and, at up to €500 billion (£435 bn) or more, represent the single most costly piece of engineering ever.

But, the pair reason, to do nothing could cost the people of Europe perhaps 10 times as much as coasts eroded, the sea overwhelmed the Low Countries, reshaped the contours of a continent and forced 25 million people to move inland.

In their paper in the Bulletin of the American Meteorological SocietySjoerd Groeskamp of the Royal Netherlands Institute for Sea Research and Joakim Kjellsson of Geomar, the Helmholtz oceanographic research centre in Kiel, Germany, concede that what they propose “may seem an overwhelming and unrealistic solution at first.”

But compared with the cost of inaction, or the cost of managed retreat from the coastline that would displace millions, it could be the cheapest option. “It might be impossible to truly fathom the magnitude of the threat that global-mean sea level rise poses,” they warn.

Least bad option

Global average temperatures have risen by 1°C and sea levels by 21 cms (8 inches) since 1880. Sea level rise lags behind atmospheric warming, but the guess is that every degree Celsius in the air will be followed eventually by 2.3 metres (7.5 feet) of higher seas.

By 2100, temperatures could have risen more than 3°C and sea levels by up to 1.5 metres (5 feet). If nations carry on burning fossil fuels the icecaps will melt inexorably, and by 2500 seas could have risen by 10 metres.

“The best solution will always be the treatment of the cause: human-caused climate change,” they write. However, if nations do not act to control the greenhouse gas emissions and forest destruction that cause global heating, and ever higher tides, then solutions such as the North European Enclosure Dam, known for short as NEED, are the only option.

The two researchers propose a barrier, a dike of sloping sides 50 metres wide across the North Sea from Bergen in Norway to the north-east tip of Scotland, via the Shetland and Orkney Islands.

This would be 475 kms (295 miles) long, with an average depth of 127 metres (417 feet), but would have to cross a trench more than 300 metres (985 feet) deep. To withstand continued sea level rise beyond 2500, it would need to be 20 metres or more above the Atlantic waves.

“This dam is mainly a call to do something about climate change now. If we do nothing, then this extreme dam might just be the only solution”

The 160 kms (100 miles) of sea defence from south-west England to the westernmost point of France would be a little less problematic: sea depths are hardly more than 100 metres (330 feet).

But the engineers would also have to factor in the 40,000 cubic metres of river water that would discharge into this enclosed basin every second. This would mean the same volume would need pumping continuously into the Atlantic on the far side of the dikes.

Since the barrier would enclose a number of the world’s great shipping ports, there would have to be sluice gates to let the big ships through, or alternatively new ports on the ocean side of the barriers.

The very nature of the enclosed North Sea would begin to change. Within a decade or two, it would start to turn into a freshwater lake: it would be the end of centuries of a fishing industry.

It could – the scientists admit their calculations are of the “back of an envelope” variety – be done. They scaled up the costs of the world’s largest dikes so far in the Netherlands and South Korea, to calculate the 51 billion tonnes of sand needed for the project. This is about what the world uses every year in construction.

Technology tested

They note that fixed seabed oil platforms have been constructed to a depth of 500 metres (1,640 feet), so engineers already know how to do such things. Pumps of the scale required to handle the incoming river discharges are already in use, but they would be needed in their hundreds.

And although the cost would reach somewhere between €250-550 bn (£220-480 bn), this − spread over the 20 years the project would take − would represent only at most 0.32% of the gross domestic product of the UK, Netherlands, Germany, Belgium and Denmark combined: the five nations with most to lose from the rising tides.

It would, the authors argue, cost just the Netherlands – which already has 3,600 km (2,240 miles) of flood protection − a third of that sum to defend against sea level rises of only 1.5 metres. The good news is that, if such a project worked for western Europe, then the same techniques could enclose the Irish Sea, the Mediterranean, the Red Sea and the Persian Gulf.

“This dam makes it almost tangible what the consequences of continued sea level rise will be; a rise of 10 metres by the year 2500 according to the bleakest scenarios,” said Dr Groeskamp.

“This dam is therefore mainly a call to do something about climate change now. If we do nothing, then this extreme dam might just be the only solution.” − Climate News Network