Tag Archives: Oceans

Ice-free Arctic Ocean allowed ancient carbon leaks

As the world warms, more greenhouse gas will enter the atmosphere. Researchers now think an ice-free Arctic Ocean explains how and why.

LONDON, 10 January, 2020 – Deep in a cave in Siberia, Israeli, Russian and British scientists have identified evidence of periodic losses of carbon from the permafrost. And the unexpected link is not simply with peak periods of bygone global warming, but with an ice-free Arctic Ocean.

The escape into the atmosphere of prodigious volumes of methane and carbon dioxide from the thawing soils is in step not with average planetary temperature rise, but with long periods when the Arctic Ocean is free of ice every summer.

Fact one: about one quarter of land in the northern hemisphere is now, and has been for much of the last half million years, permanently frozen, and with it about twice as much atmospheric carbon – in the form of peat and preserved vegetation – as there exists freely in the planetary atmosphere.

Fact two: in the most recent decades, sea ice has been both thinning and dwindling rapidly, and the polar ocean could by 2050 become almost entirely ice-free in the summer months.

“This discovery about the behaviour of the permafrost suggests that the expected loss of Arctic sea ice will accelerate melting of the permafrost presently found across much of Siberia”

And this twist in the tale of a rapidly-warming Arctic is preserved in stalagmite formations in a cave deep beneath the rim of the Arctic Circle in Siberia.

The chronology of stalagmite and stalactite development can be established precisely by the pattern of uranium and lead isotope deposits in formations, built up imperceptibly by the steady drip of water from, and through, the soils far above.

That is, the speleothems – a geologist’s catch-all word for both stalactite and stalagmite – form fastest when the permafrost has thawed. And unexpectedly, the periods of thaw did not match the peaks of interglacial warming during the last 1.35 million years. They did however coincide with periods when the Arctic was ice-free in the summer.

“This discovery about the behaviour of the permafrost suggests that the expected loss of Arctic sea ice in the future will accelerate melting of the permafrost presently found across much of Siberia,” said Gideon Henderson of the University of Oxford, and one of the authors of a new study in the journal Nature.

Permafrost in jeopardy

The argument goes like this: if there is no sea ice then more heat and moisture is delivered from the ocean to the atmosphere, with warmer air flowing over Siberia, and therefore more autumn snowfall.

A blanket of snow insulates the soil beneath from the extreme winter cold, so ground temperatures go up, to unsettle the permafrost and start a thaw that leads to accelerated plant decay and ever-increasing escape of carbon dioxide and methane that would otherwise have been frozen into the permafrost.

So the stalagmites endure as evidence of these warmer soils and survive as a direct link to periods of ice-free ocean.

“If these processes continue during modern climate change, future loss of summer Arctic sea ice will accelerate the thawing of Siberian permafrost,” the scientists say. – Climate News Network

As the world warms, more greenhouse gas will enter the atmosphere. Researchers now think an ice-free Arctic Ocean explains how and why.

LONDON, 10 January, 2020 – Deep in a cave in Siberia, Israeli, Russian and British scientists have identified evidence of periodic losses of carbon from the permafrost. And the unexpected link is not simply with peak periods of bygone global warming, but with an ice-free Arctic Ocean.

The escape into the atmosphere of prodigious volumes of methane and carbon dioxide from the thawing soils is in step not with average planetary temperature rise, but with long periods when the Arctic Ocean is free of ice every summer.

Fact one: about one quarter of land in the northern hemisphere is now, and has been for much of the last half million years, permanently frozen, and with it about twice as much atmospheric carbon – in the form of peat and preserved vegetation – as there exists freely in the planetary atmosphere.

Fact two: in the most recent decades, sea ice has been both thinning and dwindling rapidly, and the polar ocean could by 2050 become almost entirely ice-free in the summer months.

“This discovery about the behaviour of the permafrost suggests that the expected loss of Arctic sea ice will accelerate melting of the permafrost presently found across much of Siberia”

And this twist in the tale of a rapidly-warming Arctic is preserved in stalagmite formations in a cave deep beneath the rim of the Arctic Circle in Siberia.

The chronology of stalagmite and stalactite development can be established precisely by the pattern of uranium and lead isotope deposits in formations, built up imperceptibly by the steady drip of water from, and through, the soils far above.

That is, the speleothems – a geologist’s catch-all word for both stalactite and stalagmite – form fastest when the permafrost has thawed. And unexpectedly, the periods of thaw did not match the peaks of interglacial warming during the last 1.35 million years. They did however coincide with periods when the Arctic was ice-free in the summer.

“This discovery about the behaviour of the permafrost suggests that the expected loss of Arctic sea ice in the future will accelerate melting of the permafrost presently found across much of Siberia,” said Gideon Henderson of the University of Oxford, and one of the authors of a new study in the journal Nature.

Permafrost in jeopardy

The argument goes like this: if there is no sea ice then more heat and moisture is delivered from the ocean to the atmosphere, with warmer air flowing over Siberia, and therefore more autumn snowfall.

A blanket of snow insulates the soil beneath from the extreme winter cold, so ground temperatures go up, to unsettle the permafrost and start a thaw that leads to accelerated plant decay and ever-increasing escape of carbon dioxide and methane that would otherwise have been frozen into the permafrost.

So the stalagmites endure as evidence of these warmer soils and survive as a direct link to periods of ice-free ocean.

“If these processes continue during modern climate change, future loss of summer Arctic sea ice will accelerate the thawing of Siberian permafrost,” the scientists say. – Climate News Network

Atlantic current could falter before 2100

The Atlantic current won’t come to a full stop the day after tomorrow. But it could face a temporary halt later this century.

LONDON, 3 January, 2020 − European scientists think they have settled one of the more alarming questions of the climate crisis: the potential collapse of the Atlantic current, the Gulf Stream that delivers heat from the tropics to the Arctic.

The answer is clear. Total collapse is not likely for another 1000 years. But there is roughly a one in six chance in the next century that the flow of the north Atlantic current may temporarily halt or falter because of climate change.

That is because faster melting of the Greenland ice cap, and more freshwater in the Arctic Ocean, could trigger a slowdown in what scientists like to call the Atlantic meridional overturning circulation.

And a team of US researchers has separately highlighted one of the potential mechanisms of ocean change: for every 1°C rise in average global temperature, there will be roughly six days fewer on which many of the world’s rivers are frozen, which will mean more freshwater in the northern seas.

The findings are based in the first case on sophisticated use of computer simulations, and in the second on the careful study of 400,000 satellite images collected over more than 30 years.

“The Dutch scientists now think that the likelihood of even a temporary halt is only 15%. This is more or less the chance offered in the grim game of Russian roulette”

Researchers from the universities of Groningen and Utrecht say, in the journal Scientific Reports, that they modelled the likelihood and impact of small changes in the flow of freshwater into the ocean at high latitudes.

The Atlantic current – sometimes called the Gulf Stream – is a massive flow of warm, salty water from the tropics to the Arctic that keeps  northwestern Europe much warmer than, for example, the same latitudes of North America.

As the water flows north, it cools and becomes more dense, and begins to sink below the fresh meltwater of the summer Arctic: the cold, dense, salty water then flows along the sea bed southwards, and this one dramatic global oceanic conveyor belt ultimately delivers nutrients and dissolved oxygen to the Southern Ocean. It also stores dissolved carbon dioxide, distributes heat and moderates high latitude weather.

But in the past 150 years the flow has been weakening, and there have been fears that the circulation could halt entirely, with unforeseeable consequences. This notional failure became the trigger for a 2004 disaster movie called The Day After Tomorrow. Something so sudden and catastrophic as the Hollywood version was never going to happen – but there have been repeated fears that the weakening could continue, and tip the planet’s climate into a new and potentially dangerous state.

The Dutch scientists now think that the likelihood of even a temporary halt is only 15%. This is more or less the chance offered in the grim game of Russian roulette, in which a player spins a six-chambered revolver with one bullet in it, and points it at his or her head.

River ice lost

Their model simulated small changes in the delivery of freshwater. This is likely to accelerate however, according to research in the journal Nature. Researchers combed through 407,880 satellite pictures taken between 1984 and 2018, to find that 56% of rivers were affected by winter freezing, which masked altogether 87,000 square kilometres of water surface.

Freezing is important to both humans and wild things: frozen rivers traditionally have provided good surfaces for ground transport in the high latitudes. The act of freezing also regulates greenhouse gas emissions that would otherwise escape from the rivers. Ice-jams during the spring melt can trigger flooding, which – though damaging to human settlements – spreads fresh water, nutrients and sediments around the flood plains.

But these benefits are at risk. The researchers found that river and lake surfaces were freezing ever later, as global temperatures crept up, and that the world had lost 2.5% of its river ice in the last 30 years.

If the world’s nations stick to the agreement reached in Paris in 2015 and contain global heating to just 2°C above the average for most of human history, then by the end of the century the world could see a reduction of another 16 days in the length of ice cover, compared with the present, they calculate.

If they achieve the Paris ideal of no more than 1.5°C, this extra ice-free period could be reduced to just over seven days. Right now, global average temperatures are already 1°C above the historic average, and the planet is on course for a warming by the end of the century of more than 3°C. − Climate News Network

The Atlantic current won’t come to a full stop the day after tomorrow. But it could face a temporary halt later this century.

LONDON, 3 January, 2020 − European scientists think they have settled one of the more alarming questions of the climate crisis: the potential collapse of the Atlantic current, the Gulf Stream that delivers heat from the tropics to the Arctic.

The answer is clear. Total collapse is not likely for another 1000 years. But there is roughly a one in six chance in the next century that the flow of the north Atlantic current may temporarily halt or falter because of climate change.

That is because faster melting of the Greenland ice cap, and more freshwater in the Arctic Ocean, could trigger a slowdown in what scientists like to call the Atlantic meridional overturning circulation.

And a team of US researchers has separately highlighted one of the potential mechanisms of ocean change: for every 1°C rise in average global temperature, there will be roughly six days fewer on which many of the world’s rivers are frozen, which will mean more freshwater in the northern seas.

The findings are based in the first case on sophisticated use of computer simulations, and in the second on the careful study of 400,000 satellite images collected over more than 30 years.

“The Dutch scientists now think that the likelihood of even a temporary halt is only 15%. This is more or less the chance offered in the grim game of Russian roulette”

Researchers from the universities of Groningen and Utrecht say, in the journal Scientific Reports, that they modelled the likelihood and impact of small changes in the flow of freshwater into the ocean at high latitudes.

The Atlantic current – sometimes called the Gulf Stream – is a massive flow of warm, salty water from the tropics to the Arctic that keeps  northwestern Europe much warmer than, for example, the same latitudes of North America.

As the water flows north, it cools and becomes more dense, and begins to sink below the fresh meltwater of the summer Arctic: the cold, dense, salty water then flows along the sea bed southwards, and this one dramatic global oceanic conveyor belt ultimately delivers nutrients and dissolved oxygen to the Southern Ocean. It also stores dissolved carbon dioxide, distributes heat and moderates high latitude weather.

But in the past 150 years the flow has been weakening, and there have been fears that the circulation could halt entirely, with unforeseeable consequences. This notional failure became the trigger for a 2004 disaster movie called The Day After Tomorrow. Something so sudden and catastrophic as the Hollywood version was never going to happen – but there have been repeated fears that the weakening could continue, and tip the planet’s climate into a new and potentially dangerous state.

The Dutch scientists now think that the likelihood of even a temporary halt is only 15%. This is more or less the chance offered in the grim game of Russian roulette, in which a player spins a six-chambered revolver with one bullet in it, and points it at his or her head.

River ice lost

Their model simulated small changes in the delivery of freshwater. This is likely to accelerate however, according to research in the journal Nature. Researchers combed through 407,880 satellite pictures taken between 1984 and 2018, to find that 56% of rivers were affected by winter freezing, which masked altogether 87,000 square kilometres of water surface.

Freezing is important to both humans and wild things: frozen rivers traditionally have provided good surfaces for ground transport in the high latitudes. The act of freezing also regulates greenhouse gas emissions that would otherwise escape from the rivers. Ice-jams during the spring melt can trigger flooding, which – though damaging to human settlements – spreads fresh water, nutrients and sediments around the flood plains.

But these benefits are at risk. The researchers found that river and lake surfaces were freezing ever later, as global temperatures crept up, and that the world had lost 2.5% of its river ice in the last 30 years.

If the world’s nations stick to the agreement reached in Paris in 2015 and contain global heating to just 2°C above the average for most of human history, then by the end of the century the world could see a reduction of another 16 days in the length of ice cover, compared with the present, they calculate.

If they achieve the Paris ideal of no more than 1.5°C, this extra ice-free period could be reduced to just over seven days. Right now, global average temperatures are already 1°C above the historic average, and the planet is on course for a warming by the end of the century of more than 3°C. − Climate News Network

Marine climate impacts are intensifying

Fish catches are falling in the Gulf of Maine, Baltic cod are getting smaller. Sharks suffer acid waters’ effects as marine climate impacts grow.

LONDON, 20 December, 2019 – Marine climate impacts are starting to make their mark on marine life at almost every level, according to a range of entirely unrelated scientific studies published in the last month.

Baltic codfish – a valuable commercial catch – have steadily become smaller, scrawnier and less valuable because of the loss of oxygen in ocean waters as a consequence of an increasingly warmer world.

Changes in climate over the last two decades have cost the fishermen of New England their jobs: their numbers have fallen by 16% since 1996 as the total catch has fallen, along with fishermen’s incomes.

The change may be linked to a natural ocean climate cycle, but nobody can be sure the decline will not continue as waters warm in response to ever higher atmospheric levels of carbon dioxide, driven by ever greater use of fossil fuels to power modern economic growth.

That steady rise in carbon dioxide means that marine waters are also becoming steadily more acidic, and this could be bad news for the sharks. Laboratory experiments suggest they can respond to short-term changes in water chemistry, but in the long term increasingly acidic waters can begin to dissolve not just the characteristic skin scales of the shark family, but the teeth as well.

And if environmental change goes on hitting tropical corals and the anemones that co-exist with them, then one of the world’s most iconic and culturally popular species could also disappear: the clownfish sub-family Amphiprioninae may not survive the continued bleaching of the coral reefs. Amphiprion ocellaris swam into the world’s hearts as the much sought-after cartoon character in the 2003 film Finding Nemo.

“We find that Nemo is at the mercy of a habitat that is degrading more and more every year”

Scientists based in the US and Sweden report in the journal Biology Letters that the average weight of specimens of Gadus morhua or the cod fish 40 cms long had dropped from 900 to 600 grams in the last 30 years.

They examined the otoliths or ear stones of 134 individuals trawled in the last months of the Baltic winter to read the evidence from trace elements such as magnesium and manganese and identify the cause: the continued fall in sea water oxygen levels as a consequence of global warming and pollution.

“The cod themselves are telling us through their internal logbooks that they’re affected by hypoxia [reduced oxygen availability], which we know is driven by climate change and nutrient loading,” said Karin Limburg, an ecologist at the State University of New York, who led the study. “Our findings suggest fish are in a worse condition because of hypoxia.”

In the Gulf of Maine, off the US Atlantic coast, catches of fish and shellfish have been falling, and with them the number of people employed in the fishery. Kimberly Oremus of the University of Delaware reports in the Proceedings of the National Academy of Sciences that successive warm winters have hit the catch, and incomes.

Pattern found

She matched decades of climate data, landing figures and sales data to identify a pattern of decline linked principally to a hot-and-cold pattern of change known as the North Atlantic Oscillation.

“New England waters are among the fastest-warming in the world,” she said. “Warmer than average sea surface temperatures have been shown to impact the productivity of lobsters, sea scallops, groundfish and other fisheries important to the region, especially when they are most vulnerable, from spawning through their first year of life.”

The region has 34,000 commercial fishermen, a significant proportion of the 166,000 or so throughout the whole of the US. The oscillation is a shift in ocean temperatures over decades, and catches could improve in decades to come – but marine waters worldwide are warming.

“This is an important signal to incorporate into the fisheries management process,” she said. “We need to figure out what climate is doing to fisheries in order to cope with it.”

Acid hazard

One important part of the marine ecosystem might not in the long run be able to cope: short episodes of hypercapnia, or a dramatic rise in dissolved carbon dioxide, are a feature linked to seasonal oceanic upwellings, and can last for days in some waters before normal ocean chemistry is restored.

In the journal Scientific Reports, European and South Africa researchers offer evidence that though cartilaginous fishes – the huge and varied family to which sharks belong – have evolved to cope with such spells, ever more acidic oceans offer a new hazard.

They caught a number of puffadder shysharks, known to scientists as Haploblepharus edwardsii and a species small enough for laboratory tanks, from shallow waters off South Africa and exposed them to acidic conditions predicted by the year 2300.

The increasingly acid environment was, literally, corrosive. Their specimens lost a quarter of their skin denticles – the shark equivalent of scales. Sharks’ teeth are made of the same biological fabric as the skin, and the implication is that such losses could, in their words “compromise hydrodynamics and skin protection.” In other words, some of the ocean’s most feared predators might have trouble both swimming and feeding.

Poor adapters

Australian and US scientists have more bad news for Nemo, the film star from the clownfish family. Rather than experiment in a laboratory tank, they monitored the numbers and the DNA of real life specimens for decades in Kimbe Bay off Papua-New Guinea. As waters warmed and began to bleach the coral reefs, the anemones that live in the reefs were put at risk.

They report in Ecology Letters that the tiny clownfish that live in the anemone tentacles proved bad at adapting to environmental change. The implication is that, as the coral reefs are lost, many species could be homeless and helpless.

“We find that Nemo is at the mercy of a habitat that is degrading more and more every year,” said Serge Planes of the French National Centre of Scientific Research, and one of the authors.

“To expect a clownfish to genetically adapt at a pace that would allow it to persist is unreasonable.” And Simon Thorrold of the Woods Hole Oceanographic Institution in the US added: “It seems Nemo won’t be able to save himself.” – Climate News Network

Fish catches are falling in the Gulf of Maine, Baltic cod are getting smaller. Sharks suffer acid waters’ effects as marine climate impacts grow.

LONDON, 20 December, 2019 – Marine climate impacts are starting to make their mark on marine life at almost every level, according to a range of entirely unrelated scientific studies published in the last month.

Baltic codfish – a valuable commercial catch – have steadily become smaller, scrawnier and less valuable because of the loss of oxygen in ocean waters as a consequence of an increasingly warmer world.

Changes in climate over the last two decades have cost the fishermen of New England their jobs: their numbers have fallen by 16% since 1996 as the total catch has fallen, along with fishermen’s incomes.

The change may be linked to a natural ocean climate cycle, but nobody can be sure the decline will not continue as waters warm in response to ever higher atmospheric levels of carbon dioxide, driven by ever greater use of fossil fuels to power modern economic growth.

That steady rise in carbon dioxide means that marine waters are also becoming steadily more acidic, and this could be bad news for the sharks. Laboratory experiments suggest they can respond to short-term changes in water chemistry, but in the long term increasingly acidic waters can begin to dissolve not just the characteristic skin scales of the shark family, but the teeth as well.

And if environmental change goes on hitting tropical corals and the anemones that co-exist with them, then one of the world’s most iconic and culturally popular species could also disappear: the clownfish sub-family Amphiprioninae may not survive the continued bleaching of the coral reefs. Amphiprion ocellaris swam into the world’s hearts as the much sought-after cartoon character in the 2003 film Finding Nemo.

“We find that Nemo is at the mercy of a habitat that is degrading more and more every year”

Scientists based in the US and Sweden report in the journal Biology Letters that the average weight of specimens of Gadus morhua or the cod fish 40 cms long had dropped from 900 to 600 grams in the last 30 years.

They examined the otoliths or ear stones of 134 individuals trawled in the last months of the Baltic winter to read the evidence from trace elements such as magnesium and manganese and identify the cause: the continued fall in sea water oxygen levels as a consequence of global warming and pollution.

“The cod themselves are telling us through their internal logbooks that they’re affected by hypoxia [reduced oxygen availability], which we know is driven by climate change and nutrient loading,” said Karin Limburg, an ecologist at the State University of New York, who led the study. “Our findings suggest fish are in a worse condition because of hypoxia.”

In the Gulf of Maine, off the US Atlantic coast, catches of fish and shellfish have been falling, and with them the number of people employed in the fishery. Kimberly Oremus of the University of Delaware reports in the Proceedings of the National Academy of Sciences that successive warm winters have hit the catch, and incomes.

Pattern found

She matched decades of climate data, landing figures and sales data to identify a pattern of decline linked principally to a hot-and-cold pattern of change known as the North Atlantic Oscillation.

“New England waters are among the fastest-warming in the world,” she said. “Warmer than average sea surface temperatures have been shown to impact the productivity of lobsters, sea scallops, groundfish and other fisheries important to the region, especially when they are most vulnerable, from spawning through their first year of life.”

The region has 34,000 commercial fishermen, a significant proportion of the 166,000 or so throughout the whole of the US. The oscillation is a shift in ocean temperatures over decades, and catches could improve in decades to come – but marine waters worldwide are warming.

“This is an important signal to incorporate into the fisheries management process,” she said. “We need to figure out what climate is doing to fisheries in order to cope with it.”

Acid hazard

One important part of the marine ecosystem might not in the long run be able to cope: short episodes of hypercapnia, or a dramatic rise in dissolved carbon dioxide, are a feature linked to seasonal oceanic upwellings, and can last for days in some waters before normal ocean chemistry is restored.

In the journal Scientific Reports, European and South Africa researchers offer evidence that though cartilaginous fishes – the huge and varied family to which sharks belong – have evolved to cope with such spells, ever more acidic oceans offer a new hazard.

They caught a number of puffadder shysharks, known to scientists as Haploblepharus edwardsii and a species small enough for laboratory tanks, from shallow waters off South Africa and exposed them to acidic conditions predicted by the year 2300.

The increasingly acid environment was, literally, corrosive. Their specimens lost a quarter of their skin denticles – the shark equivalent of scales. Sharks’ teeth are made of the same biological fabric as the skin, and the implication is that such losses could, in their words “compromise hydrodynamics and skin protection.” In other words, some of the ocean’s most feared predators might have trouble both swimming and feeding.

Poor adapters

Australian and US scientists have more bad news for Nemo, the film star from the clownfish family. Rather than experiment in a laboratory tank, they monitored the numbers and the DNA of real life specimens for decades in Kimbe Bay off Papua-New Guinea. As waters warmed and began to bleach the coral reefs, the anemones that live in the reefs were put at risk.

They report in Ecology Letters that the tiny clownfish that live in the anemone tentacles proved bad at adapting to environmental change. The implication is that, as the coral reefs are lost, many species could be homeless and helpless.

“We find that Nemo is at the mercy of a habitat that is degrading more and more every year,” said Serge Planes of the French National Centre of Scientific Research, and one of the authors.

“To expect a clownfish to genetically adapt at a pace that would allow it to persist is unreasonable.” And Simon Thorrold of the Woods Hole Oceanographic Institution in the US added: “It seems Nemo won’t be able to save himself.” – Climate News Network

Heat the Arctic to cool the Earth, scientists say

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

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

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

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

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

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

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

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

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

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

More heat escapes

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

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

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

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

Unknown consequences

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

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

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

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

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

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

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

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

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

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

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

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

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

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

More heat escapes

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

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

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

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

Unknown consequences

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

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

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

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

Ultra-fast computers could avert global disaster

The world can be saved. It needs global co-operation, careful research and the building of ultra-fast computers.

LONDON, 13 December, 2019 – The way to steer the planet safely away from overwhelming climate crisis may sound familiar, though it’s staggeringly ambitious: just use incredibly powerful and ultra-fast computers.

Studies in two separate journals have called for new thinking about global change. One warns that only a genuine accommodation with nature can save humankind from catastrophic change. The other argues that present understanding of the trajectories of global heating is so uncertain that what is needed is a global co-operation to deliver what scientists call exascale supercomputer climate modelling: exascale means calculations at rates of a billion billion operations a second.

There’s a snag: nobody has yet built a working exascale computer, though several groups hope to succeed within a few years. But when it’s done it could transform the prospects of life on Earth.

“We cannot save the planet – and ourselves – until we understand how tightly woven people and the natural benefits that allow us to survive are,” said Jianguo Liu of Michigan State University, one of the authors of a paper in the journal Science.

“We have learned new ways to understand these connections, even as they spread across the globe. This strategy has given us the power to understand the full scope of the problem, which allows us to find true solutions.”

“Human actions are causing the fabric of life to unravel, posing serious risks for the quality of life of people”

And Tim Palmer of Oxford University, an author of a perspective paper in the Proceedings of the National Academy of Sciences, has called for a new and international investment in sophisticated climate modelling, exploiting a new generation of computers, in much the same way that physicists at CERN in Geneva co-operated to explore the sequence of events in the first microsecond of creation.

“By comparison with new particle colliders or space telescopes, the amount needed, maybe around $100 million a year, is very modest indeed. In addition, the benefit/cost ratio to society of having a much clearer picture of the dangers we are facing in the coming decades by our ongoing actions, seems extraordinarily large,” he said.

“To be honest, all is needed is the will to work together across nations, on such a project. Then it will happen.”

The point made by authors of the Science study is that humankind depends acutely on the natural world for at least 18 direct benefits: these include pollination and the dispersal of seeds, the regulation of clean air, and of climate, and of fresh water, the protection of topsoils, the control of potential pests and diseases, the supplies of energy, food and animal fodder, the supplies of materials and fabrics and yields of new medicines and biochemical compounds.

Massive change

“Human actions are causing the fabric of life to unravel, posing serious risks for the quality of life of people”, the authors warn.

“Human actions have directly altered at least 70% of land surface; 66% of ocean surface is experiencing cumulative impacts; around 85% of wetland area has been lost since the 1700s and 77% of rivers longer than 1000 km no longer flow freely from source to sea.”

There was a need for “transformative action” on a global scale to address root economic, social and technological causes and to avert catastrophic decline of the living world. “Although the challenge is formidable, every delay will make the task harder”, they warn.

But in a world of rapid change – with species at increasing risk of extinction and global heating about to trigger catastrophic climate change – there is still the challenge of working out what the implications of any change might be.

The argument is that human society must change, and so too must the scientific community. Climate modelling might deliver broad answers, but researchers would still need to be sure what might work best in any particular circumstances, and that would require new and vastly more complex levels of mathematical calculation and data interpretation.

Space-race urgency

Professor Palmer and his colleague Bjorn Stevens of the Max Planck Institute for Meteorology in Hamburg call for better understanding of the need for change.

“What is needed is the urgency of the space race aimed, not at the Moon or Mars, but rather toward harnessing the promise of exascale supercomputing to reliably simulate Earth’s regional climate (and associated extremes) globally”, they argue.

“This will only be possible if the broader climate science community begins to articulate its dissatisfaction with business as usual – not just among themselves, but externally to those who seek to use the models for business, policy, or humanitarian reasons.

“Failing to do so becomes an ethical issue in that it saddles us with the status quo: a strategy that hopes, against all evidence, to surmount the abyss between scientific capability and societal needs.” – Climate News Network

The world can be saved. It needs global co-operation, careful research and the building of ultra-fast computers.

LONDON, 13 December, 2019 – The way to steer the planet safely away from overwhelming climate crisis may sound familiar, though it’s staggeringly ambitious: just use incredibly powerful and ultra-fast computers.

Studies in two separate journals have called for new thinking about global change. One warns that only a genuine accommodation with nature can save humankind from catastrophic change. The other argues that present understanding of the trajectories of global heating is so uncertain that what is needed is a global co-operation to deliver what scientists call exascale supercomputer climate modelling: exascale means calculations at rates of a billion billion operations a second.

There’s a snag: nobody has yet built a working exascale computer, though several groups hope to succeed within a few years. But when it’s done it could transform the prospects of life on Earth.

“We cannot save the planet – and ourselves – until we understand how tightly woven people and the natural benefits that allow us to survive are,” said Jianguo Liu of Michigan State University, one of the authors of a paper in the journal Science.

“We have learned new ways to understand these connections, even as they spread across the globe. This strategy has given us the power to understand the full scope of the problem, which allows us to find true solutions.”

“Human actions are causing the fabric of life to unravel, posing serious risks for the quality of life of people”

And Tim Palmer of Oxford University, an author of a perspective paper in the Proceedings of the National Academy of Sciences, has called for a new and international investment in sophisticated climate modelling, exploiting a new generation of computers, in much the same way that physicists at CERN in Geneva co-operated to explore the sequence of events in the first microsecond of creation.

“By comparison with new particle colliders or space telescopes, the amount needed, maybe around $100 million a year, is very modest indeed. In addition, the benefit/cost ratio to society of having a much clearer picture of the dangers we are facing in the coming decades by our ongoing actions, seems extraordinarily large,” he said.

“To be honest, all is needed is the will to work together across nations, on such a project. Then it will happen.”

The point made by authors of the Science study is that humankind depends acutely on the natural world for at least 18 direct benefits: these include pollination and the dispersal of seeds, the regulation of clean air, and of climate, and of fresh water, the protection of topsoils, the control of potential pests and diseases, the supplies of energy, food and animal fodder, the supplies of materials and fabrics and yields of new medicines and biochemical compounds.

Massive change

“Human actions are causing the fabric of life to unravel, posing serious risks for the quality of life of people”, the authors warn.

“Human actions have directly altered at least 70% of land surface; 66% of ocean surface is experiencing cumulative impacts; around 85% of wetland area has been lost since the 1700s and 77% of rivers longer than 1000 km no longer flow freely from source to sea.”

There was a need for “transformative action” on a global scale to address root economic, social and technological causes and to avert catastrophic decline of the living world. “Although the challenge is formidable, every delay will make the task harder”, they warn.

But in a world of rapid change – with species at increasing risk of extinction and global heating about to trigger catastrophic climate change – there is still the challenge of working out what the implications of any change might be.

The argument is that human society must change, and so too must the scientific community. Climate modelling might deliver broad answers, but researchers would still need to be sure what might work best in any particular circumstances, and that would require new and vastly more complex levels of mathematical calculation and data interpretation.

Space-race urgency

Professor Palmer and his colleague Bjorn Stevens of the Max Planck Institute for Meteorology in Hamburg call for better understanding of the need for change.

“What is needed is the urgency of the space race aimed, not at the Moon or Mars, but rather toward harnessing the promise of exascale supercomputing to reliably simulate Earth’s regional climate (and associated extremes) globally”, they argue.

“This will only be possible if the broader climate science community begins to articulate its dissatisfaction with business as usual – not just among themselves, but externally to those who seek to use the models for business, policy, or humanitarian reasons.

“Failing to do so becomes an ethical issue in that it saddles us with the status quo: a strategy that hopes, against all evidence, to surmount the abyss between scientific capability and societal needs.” – Climate News Network

Earth nears irreversible tipping points

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

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

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

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

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

Happening now

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

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

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

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

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

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

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

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

Inadequate pledges

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

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

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

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

Timescale controlled

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

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

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

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

Risks multiply

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

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

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

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

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

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

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

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

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

Happening now

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

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

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

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

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

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

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

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

Inadequate pledges

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

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

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

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

Timescale controlled

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

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

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

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

Risks multiply

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

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

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

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

New land height metric raises sea level rise risk

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

 

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

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

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

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

Protection in question

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

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

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

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

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

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

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

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

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

Multiple risks

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

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

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

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

US coasts threatened

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

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

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

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

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

 

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

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

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

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

Protection in question

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

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

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

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

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

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

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

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

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

Multiple risks

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

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

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

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

US coasts threatened

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

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

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

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

Penguins in peril as winds change and heat rises

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

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

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

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

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

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

Numbers fluctuate

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

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

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

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

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

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

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

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

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

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

Wider appeal

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

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

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

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

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

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

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

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

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

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

Numbers fluctuate

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

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

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

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

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

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

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

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

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

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

Wider appeal

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

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

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

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

Rugby stars are losing their Pacific islands

Whatever happens on the pitches, rugby stars from the Pacific islands face a battle back home to save their ancestral lands from rising sea levels.

LONDON, 1 October, 2019 – Players from the Pacific islands are performing a prominent role in the intense battles at present going on at the rugby world cup in Japan.

Away from the rough and tumble on the pitch, the players are facing an even bigger challenge back home as their island nations come under increasing threat from climate change, in particular from ever-rising sea levels.

A recent report by the Intergovernmental Panel on Climate Change (IPCC) warns of the catastrophic effect rising sea levels – mainly caused by the melting of ice at the poles – will have on billions of people living in coastal areas and in island states around the world.

In the low-lying island nations of the Pacific, climate change is already having an impact. Coastal communities are frequently inundated by rising seas. Salty seawater poisons precious supplies of fresh water.

Crops are lost and homes damaged. Warming seas are killing off coral reefs, a key source of fish and an industry on which many islanders depend for their living.

Exploited

A report by the charity Christian Aid, focusing on the rugby world cup, says that while Pacific island teams Fiji, Tonga and Samoa are playing a central role in the tournament in Japan, they are, at the same time, being exploited and harmed by the actions of bigger and richer nations involved, including Australia, New Zealand and England.

The report points out that Pacific island states are among the lowest emitters of climate-changing carbon dioxide and other greenhouse gases. Yet they are among those suffering most from a warming world.

Samoa emits 0.7 tonnes of CO2 per capita each year. The equivalent figure for Australia is 16.5 tonnes and for host Japan is 10.4 tonnes.

Jonny Fa’amatuainu is a former Samoan international who has also played for rugby clubs in England, Wales and Japan.

“As a Pacific Island rugby player, tackling the climate crisis is close to my heart. My grandparents and other families who lived in a village on the coast of Samoa moved inland two years ago because of climate change”, he says.

“The island nations in the Pacific are some of the most vulnerable in the world and they have done almost nothing to cause their plight”

“The Pacific Islands are the soul of our sport and we have produced some of the most dynamic and exciting players on the planet … climate change is a crisis these countries did not cause yet it’s a fight they are suffering from the most.

“It’s a fight they need the help of the rugby community to win.”

The Christian Aid report says climate change threatens to undermine the Pacific Islands’ economies. Tourists will stop visiting and young people will be forced to leave, with up to 1.7 million likely to move from their homes in the region over the next 30 years.

Cyclone Gita, which devastated many parts of Tonga last year, was the strongest storm to hit the nation since records began. The report says global warming means such storms will be more frequent across the region in the years ahead.

The study also highlights the way in which many Pacific island rugby players are treated, being paid wages only a fraction of those earned by their counterparts in richer countries. The teams are also often excluded from various international tournaments.

Foot-dragging

“Climate change is the ultimate injustice issue and nowhere is that captured more clearly than among the nations taking part in the rugby world cup”, says Katherine Kramer of Christian Aid, the author of the report.

“The island nations in the Pacific are some of the most vulnerable in the world and they have done almost nothing to cause their plight.

“The main culprits for causing the climate crisis are European nations as well as major coal burners like Australia, the US and Japan.

“Not only have they caused the current dire situation, but they are dragging their feet on making the needed transition to a zero-carbon economy.” – Climate News Network

Whatever happens on the pitches, rugby stars from the Pacific islands face a battle back home to save their ancestral lands from rising sea levels.

LONDON, 1 October, 2019 – Players from the Pacific islands are performing a prominent role in the intense battles at present going on at the rugby world cup in Japan.

Away from the rough and tumble on the pitch, the players are facing an even bigger challenge back home as their island nations come under increasing threat from climate change, in particular from ever-rising sea levels.

A recent report by the Intergovernmental Panel on Climate Change (IPCC) warns of the catastrophic effect rising sea levels – mainly caused by the melting of ice at the poles – will have on billions of people living in coastal areas and in island states around the world.

In the low-lying island nations of the Pacific, climate change is already having an impact. Coastal communities are frequently inundated by rising seas. Salty seawater poisons precious supplies of fresh water.

Crops are lost and homes damaged. Warming seas are killing off coral reefs, a key source of fish and an industry on which many islanders depend for their living.

Exploited

A report by the charity Christian Aid, focusing on the rugby world cup, says that while Pacific island teams Fiji, Tonga and Samoa are playing a central role in the tournament in Japan, they are, at the same time, being exploited and harmed by the actions of bigger and richer nations involved, including Australia, New Zealand and England.

The report points out that Pacific island states are among the lowest emitters of climate-changing carbon dioxide and other greenhouse gases. Yet they are among those suffering most from a warming world.

Samoa emits 0.7 tonnes of CO2 per capita each year. The equivalent figure for Australia is 16.5 tonnes and for host Japan is 10.4 tonnes.

Jonny Fa’amatuainu is a former Samoan international who has also played for rugby clubs in England, Wales and Japan.

“As a Pacific Island rugby player, tackling the climate crisis is close to my heart. My grandparents and other families who lived in a village on the coast of Samoa moved inland two years ago because of climate change”, he says.

“The island nations in the Pacific are some of the most vulnerable in the world and they have done almost nothing to cause their plight”

“The Pacific Islands are the soul of our sport and we have produced some of the most dynamic and exciting players on the planet … climate change is a crisis these countries did not cause yet it’s a fight they are suffering from the most.

“It’s a fight they need the help of the rugby community to win.”

The Christian Aid report says climate change threatens to undermine the Pacific Islands’ economies. Tourists will stop visiting and young people will be forced to leave, with up to 1.7 million likely to move from their homes in the region over the next 30 years.

Cyclone Gita, which devastated many parts of Tonga last year, was the strongest storm to hit the nation since records began. The report says global warming means such storms will be more frequent across the region in the years ahead.

The study also highlights the way in which many Pacific island rugby players are treated, being paid wages only a fraction of those earned by their counterparts in richer countries. The teams are also often excluded from various international tournaments.

Foot-dragging

“Climate change is the ultimate injustice issue and nowhere is that captured more clearly than among the nations taking part in the rugby world cup”, says Katherine Kramer of Christian Aid, the author of the report.

“The island nations in the Pacific are some of the most vulnerable in the world and they have done almost nothing to cause their plight.

“The main culprits for causing the climate crisis are European nations as well as major coal burners like Australia, the US and Japan.

“Not only have they caused the current dire situation, but they are dragging their feet on making the needed transition to a zero-carbon economy.” – Climate News Network

Seabed carbon storage may help in climate crisis

The Blue Planet hasn’t been considered as a solution to the climate crisis. Three scientists advocate a sea change in global thinking: seabed carbon storage.

LONDON, 27 September, 2019 – Climate scientists say seabed carbon storage could be a new ally to help reduce greenhouse gas emissions by a volume greater than all the carbon dioxide pumped into the atmosphere from the planet’s coal-burning power stations.

It is the biggest ally possible: the 70% of the globe covered by ocean.

In a detailed argument in the journal Science, Ove Hoegh-Guldberg of the University of Queensland, Eliza Northrop of the World Resources Institute in Washington DC and Jane Lubchenco of Oregon State University outline five areas of action that could mitigate potentially calamitous climate change driven by profligate use of fossil fuels.

These include renewable energy, shipping and transport, protection of marine and coastal ecosystems, fisheries and aquaculture and – perhaps in future – carbon storage on the sea bed.

“Make no mistake: these actions are ambitious, but we argue they are necessary, could pay major dividends towards closing the emissions gap in coming decades, and achieve other co-benefits along the way”, they write.

“For far too long, the ocean has been mostly absent from policy discussions about reducing carbon emissions and meeting the challenges of climate change”

The argument was deliberately timed to coincide with a major new report by the Intergovernmental Panel on Climate Change on the oceans and the cryosphere.

If the world’s nations pursue ocean policy ambitions in the right way, they could reduce global greenhouse gas emissions by up to 4 billion tonnes of CO2 equivalent by 2030 and up to 11 billion by 2050.

And this could tot up to 21% of the reductions required in 2050 to limit warming to the declared 1.5°C target favoured at the Paris climate summit in 2015, and up to a fourth of all emissions for the formal 2°C target identified in the agreement.

“Reductions of this magnitude are larger than the annual emissions from all current coal-fired power plants worldwide,” they argue.

The first step is to set clear national targets for getting renewable energy from the restless seas, in terms of offshore wind, tidal and wave energy,  by 2030 and then by 2050.

Other benefits

Then the trio want nations to think about ways to reduce or eliminate carbon from the world’s shipping fleets. That means alternative fuels and a revolution in shore-based supply chains. Fuel efficiency in existing technologies could be improved, and hybrid power systems – including fuel cells and battery technologies – should be explored.

And, they point out, the sea itself is a carbon consumer. Mangrove swamps, seagrass meadows and salt marshes could be considered as “blue carbon ecosystems” in the way that terrestrial forests are considered “sinks” for atmospheric carbon.

These coastal and submarine “forests” make up only1.5% of the area of the land-based forests and woodlands, but their loss and degradation are equivalent to 8.4% of carbon emissions from terrestrial forests now being destroyed by human intrusion. So it would pay to restore and protect such marine habitats.

There would be other benefits: harvested seaweed could be turned into food, cattle feed, fertiliser, biofuels and bioplastics. Some seaweeds could help in even more dramatic ways.

Experiments with a red alga called Asparagopsis taxiformis, they say, “can reduce methane emissions from ruminants by up to 99% when constituting only 2% of the feed, and several other common species show potential methane reductions of 33 to 50%.”

‘Daunting’ change needed

The scientists urge a diet shift towards fish and seafood in pursuit of sustainable low-carbon protein; they also want to see the fishing industry worldwide pursue lower emissions while optimising the sustainable global catch.

“Such large-scale shifts in food policy and behaviour are daunting,” they concede. But there would be considerable climate benefits.

And, they admit, there are “considerable challenges” to the idea that carbon dioxide captured at source could be safely and cheaply stored on the seabed for many thousands of years. But they say “the theoretical potential” is very high.

“For far too long, the ocean has been mostly absent from policy discussions about reducing carbon emissions and meeting the challenges of climate change,” they conclude.

“Ocean-based actions provide increased hope that reaching the 1.5°C target might be possible, along with addressing other societal challenges, including economic development, food security and coastal community resilience.” – Climate News Network

The Blue Planet hasn’t been considered as a solution to the climate crisis. Three scientists advocate a sea change in global thinking: seabed carbon storage.

LONDON, 27 September, 2019 – Climate scientists say seabed carbon storage could be a new ally to help reduce greenhouse gas emissions by a volume greater than all the carbon dioxide pumped into the atmosphere from the planet’s coal-burning power stations.

It is the biggest ally possible: the 70% of the globe covered by ocean.

In a detailed argument in the journal Science, Ove Hoegh-Guldberg of the University of Queensland, Eliza Northrop of the World Resources Institute in Washington DC and Jane Lubchenco of Oregon State University outline five areas of action that could mitigate potentially calamitous climate change driven by profligate use of fossil fuels.

These include renewable energy, shipping and transport, protection of marine and coastal ecosystems, fisheries and aquaculture and – perhaps in future – carbon storage on the sea bed.

“Make no mistake: these actions are ambitious, but we argue they are necessary, could pay major dividends towards closing the emissions gap in coming decades, and achieve other co-benefits along the way”, they write.

“For far too long, the ocean has been mostly absent from policy discussions about reducing carbon emissions and meeting the challenges of climate change”

The argument was deliberately timed to coincide with a major new report by the Intergovernmental Panel on Climate Change on the oceans and the cryosphere.

If the world’s nations pursue ocean policy ambitions in the right way, they could reduce global greenhouse gas emissions by up to 4 billion tonnes of CO2 equivalent by 2030 and up to 11 billion by 2050.

And this could tot up to 21% of the reductions required in 2050 to limit warming to the declared 1.5°C target favoured at the Paris climate summit in 2015, and up to a fourth of all emissions for the formal 2°C target identified in the agreement.

“Reductions of this magnitude are larger than the annual emissions from all current coal-fired power plants worldwide,” they argue.

The first step is to set clear national targets for getting renewable energy from the restless seas, in terms of offshore wind, tidal and wave energy,  by 2030 and then by 2050.

Other benefits

Then the trio want nations to think about ways to reduce or eliminate carbon from the world’s shipping fleets. That means alternative fuels and a revolution in shore-based supply chains. Fuel efficiency in existing technologies could be improved, and hybrid power systems – including fuel cells and battery technologies – should be explored.

And, they point out, the sea itself is a carbon consumer. Mangrove swamps, seagrass meadows and salt marshes could be considered as “blue carbon ecosystems” in the way that terrestrial forests are considered “sinks” for atmospheric carbon.

These coastal and submarine “forests” make up only1.5% of the area of the land-based forests and woodlands, but their loss and degradation are equivalent to 8.4% of carbon emissions from terrestrial forests now being destroyed by human intrusion. So it would pay to restore and protect such marine habitats.

There would be other benefits: harvested seaweed could be turned into food, cattle feed, fertiliser, biofuels and bioplastics. Some seaweeds could help in even more dramatic ways.

Experiments with a red alga called Asparagopsis taxiformis, they say, “can reduce methane emissions from ruminants by up to 99% when constituting only 2% of the feed, and several other common species show potential methane reductions of 33 to 50%.”

‘Daunting’ change needed

The scientists urge a diet shift towards fish and seafood in pursuit of sustainable low-carbon protein; they also want to see the fishing industry worldwide pursue lower emissions while optimising the sustainable global catch.

“Such large-scale shifts in food policy and behaviour are daunting,” they concede. But there would be considerable climate benefits.

And, they admit, there are “considerable challenges” to the idea that carbon dioxide captured at source could be safely and cheaply stored on the seabed for many thousands of years. But they say “the theoretical potential” is very high.

“For far too long, the ocean has been mostly absent from policy discussions about reducing carbon emissions and meeting the challenges of climate change,” they conclude.

“Ocean-based actions provide increased hope that reaching the 1.5°C target might be possible, along with addressing other societal challenges, including economic development, food security and coastal community resilience.” – Climate News Network