Category Archives: Oceans

Ecosystem sentinels sound alarm for the oceans

Sea birds are known as ecosystem sentinels, warning of marine loss. As their numbers fall, so could the riches of the ocean.

LONDON, 7 June, 2021 − For a tern in the northern hemisphere, life may be about to take a turn for the worse. For murres or guillemots, as the temperature rises, the chance of survival takes a dive. Many of the world’s seabirds could be in trouble.

And for a mix of reasons, the birds of the southern hemisphere could also be heading into difficulties, but at a slower pace. A worldwide team of 40 
ornithologists has looked at 50 years of breeding records for 67 seabird species to find that as global temperatures notch up, breeding rates are down.

That may be just an indicator of deteriorating conditions on and below the surface of the oceans: the researchers call their seabird subjects “ecosystem sentinels”.

The scientists report in the journal Science that they used their data to test a proposition: that seabird productivity − the numbers that survive each breeding season − would track “hemispheric asymmetry” in ocean climate change and human use.

Put simply, because there is less land and fewer people south of the Equator, because the southern waters are less overfished and subjected to lower pollution levels, and because a bigger ocean space ought to absorb extremes of heat more effectively, seabird survival rates would be worse north of the line than to the south.

“When seabirds aren’t doing well, this is a red flag that something bigger is happening below the ocean’s surface”

And that is because the fish and plankton that seabirds eat can move with the climate, but the seabirds cannot: during the breeding season, they return to the same colonies. And hunt they must: the species Uria aalge, known as the murre or the guillemot, must eat half its bodyweight in fish each day to survive. When a long-term marine heatwave hit the north-east Pacific in 2015-2016, almost a million of them starved to death.

Breeding colonies also suffered. The pattern of change is not uniform: surface-feeding birds were more likely to be in decline; birds like puffins that plunged below the surface tended to fare a little better at rearing offspring to survival.

“Seabirds travel long distances − some going from one hemisphere to the other − chasing their food in the ocean. This makes them sensitive to changes in things like ocean productivity, often over a large area,” said P Dee Boersma, a conservation biologist at the University of Washington in the US.

“They have to compete with us for food. They get caught in our fishing nets. They eat our plastic, which they think is food. All of these factors can kill off large numbers of long-lived seabirds.”

She and colleagues have monitored the breeding success of a colony of Magellanic penguins in southern Argentina for 35 years. These birds go back to the water each season to feed their chicks: the further they have to swim, the greater the chance of a starved penguin chick.

Competition for food

Stormier weather on land, too, can destroy nests. Female penguins find survival tougher, and are more likely to die at sea. So the proportion of male Magellanic penguins is rising. Today the breeding population at the research site is about half of its numbers 40 years ago.

William Sydeman of the Farallon Institute in Northern California, who led the study, warned that falling seabird numbers could be an indicator of worse things happening at sea.

“What’s also at stake is the health of fish populations such as salmon and cod, as well as marine mammals and large invertebrates, such as squid, that are eating the same small forage fish and plankton that seabirds eat,” he said.

“When seabirds aren’t doing well, this is a red flag that something bigger is happening below the ocean’s surface which is concerning, because we depend on healthy oceans for quality of life.” − Climate News Network

Sea birds are known as ecosystem sentinels, warning of marine loss. As their numbers fall, so could the riches of the ocean.

LONDON, 7 June, 2021 − For a tern in the northern hemisphere, life may be about to take a turn for the worse. For murres or guillemots, as the temperature rises, the chance of survival takes a dive. Many of the world’s seabirds could be in trouble.

And for a mix of reasons, the birds of the southern hemisphere could also be heading into difficulties, but at a slower pace. A worldwide team of 40 
ornithologists has looked at 50 years of breeding records for 67 seabird species to find that as global temperatures notch up, breeding rates are down.

That may be just an indicator of deteriorating conditions on and below the surface of the oceans: the researchers call their seabird subjects “ecosystem sentinels”.

The scientists report in the journal Science that they used their data to test a proposition: that seabird productivity − the numbers that survive each breeding season − would track “hemispheric asymmetry” in ocean climate change and human use.

Put simply, because there is less land and fewer people south of the Equator, because the southern waters are less overfished and subjected to lower pollution levels, and because a bigger ocean space ought to absorb extremes of heat more effectively, seabird survival rates would be worse north of the line than to the south.

“When seabirds aren’t doing well, this is a red flag that something bigger is happening below the ocean’s surface”

And that is because the fish and plankton that seabirds eat can move with the climate, but the seabirds cannot: during the breeding season, they return to the same colonies. And hunt they must: the species Uria aalge, known as the murre or the guillemot, must eat half its bodyweight in fish each day to survive. When a long-term marine heatwave hit the north-east Pacific in 2015-2016, almost a million of them starved to death.

Breeding colonies also suffered. The pattern of change is not uniform: surface-feeding birds were more likely to be in decline; birds like puffins that plunged below the surface tended to fare a little better at rearing offspring to survival.

“Seabirds travel long distances − some going from one hemisphere to the other − chasing their food in the ocean. This makes them sensitive to changes in things like ocean productivity, often over a large area,” said P Dee Boersma, a conservation biologist at the University of Washington in the US.

“They have to compete with us for food. They get caught in our fishing nets. They eat our plastic, which they think is food. All of these factors can kill off large numbers of long-lived seabirds.”

She and colleagues have monitored the breeding success of a colony of Magellanic penguins in southern Argentina for 35 years. These birds go back to the water each season to feed their chicks: the further they have to swim, the greater the chance of a starved penguin chick.

Competition for food

Stormier weather on land, too, can destroy nests. Female penguins find survival tougher, and are more likely to die at sea. So the proportion of male Magellanic penguins is rising. Today the breeding population at the research site is about half of its numbers 40 years ago.

William Sydeman of the Farallon Institute in Northern California, who led the study, warned that falling seabird numbers could be an indicator of worse things happening at sea.

“What’s also at stake is the health of fish populations such as salmon and cod, as well as marine mammals and large invertebrates, such as squid, that are eating the same small forage fish and plankton that seabirds eat,” he said.

“When seabirds aren’t doing well, this is a red flag that something bigger is happening below the ocean’s surface which is concerning, because we depend on healthy oceans for quality of life.” − Climate News Network

2°C more heat may mean catastrophic sea level rise

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

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

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

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

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

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

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

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

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

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

On course for 3°C

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

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

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

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

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

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

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

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

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

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

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

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

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

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

On course for 3°C

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

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

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

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

Many creatures of the deep face a stifling future

The oceans will go on warming and rising for five centuries. Some creatures of the deep will have less room to breathe.

LONDON, 22 April, 2021 − Even if humans stopped all use of fossil fuels immediately, and drastically reduced greenhouse gas emissions, the oceans would go on warming. And as the waters warmed, their burden of dissolved oxygen would continue to dwindle, stifling many creatures of the deep.

This could continue for another 500 years, at the end of which oxygen loss in the seas would have multiplied fourfold. Since oxygen is vital to almost all complex life on Earth, and since the ocean − covering 70% of the globe and reaching in places to depths of almost 11 kilometres − provides by far the oldest and biggest breathing space for living things, that could commit many creatures to a slow, stifling end, according to a new study in the journal Nature Communications.

Both oxygen and carbon dioxide are soluble in seawater. The colder the water, the greater the capacity for dissolved gases, which ultimately is why polar seas are vastly and massively richer in life than tropical waters. But the latest study of the long-term consequences of carbon dioxide emissions offers a bleak picture for the future.

As the planet has warmed, so have the seas. As the greenhouse gas burden of the atmosphere has increased, so has the acidity of the ocean. And as the ocean waters have warmed, the levels of dissolved oxygen have fallen.

In the last 50 years, the ocean has on average lost 2% of its dissolved oxygen. That’s an average figure. In some parts of the water column, the loss has been much higher, directly as a consequence of global warming. And this loss will continue until around 2650.

“The deep ocean appears committed to turning into an as-yet-unrecognised area where the slogan ‘If you can’t breathe, nothing else matters’ will become reality for many centuries to come”

Andreas Oschlies of the Geomar Helmholtz Centre for Ocean Research in Kiel in Germany used a climate model of the Earth system to work out what would happen to the ocean in the long term if all carbon dioxide emissions stopped right now.

He says: “The results show that even in this extreme scenario, the oxygen depletion will continue for centuries, more than quadrupling the oxygen loss we have seen to date in the ocean.”

Most of this loss will be at depths of 2000 metres or more, partly because ocean circulation is becoming more sluggish in response to climate change. So the deepest parts of the ocean could lose more than a tenth of all the oxygen it once held before the launch of the Industrial Revolution and the accelerated use of coal, oil and gas to drive national economies. And that would be bad news for the creatures that swim and replicate at depth: some of them could face a decline of up to 25%.

And if nations could achieve the impossible and halt all emissions now, surface air temperatures would stabilise rapidly. But the oceans would go on absorbing the extra carbon dioxide already in the atmosphere. Between now and 2650, according to the calculations of Professor Oschlies, the ocean would go on absorbing another 720 billion tonnes of the gas. This is larger than all the CO2 the oceans have taken up till now: an estimated 634 billion tonnes.

Too little air

But the atmospheric heat the oceans will absorb in the next five centuries is likely to be three times the heat already absorbed up till now. This warmth alone − because warm water is less dense than cold water − will mean another 16cms of unavoidable sea level rise. And as the waters warm, the oxygen levels in that water will continue to diminish: by 2650 it will have fallen by 7.4% compared with oxygen levels a century or more ago. And this is more than three times the loss that has already happened.

Those sea creatures that had adapted over a million years to one set of oxygen levels are going to face a problem: there won’t be enough oxygen dissolved in the deep seas to support all of them. Some regions of the ocean will slowly become “dead zones”.

Oceanography is a costly science, and most of the ocean is unexplored: humans have mapped the surface and plundered the coastal waters but have yet to explore the depths in much detail over vast tracts of the planet’s largest living room.

There’s a lot more research to be done, before researchers can be sure of the ways in which human action is about to irrevocably change the submarine world. But the outlook so far is ominous.

Professor Oschlies warns: “The deep ocean appears committed to turning into an as-yet-unrecognised area where the slogan of the American Lung Association − ‘If you can’t breathe, nothing else matters’ − will become reality for many centuries to come.” − Climate News Network

The oceans will go on warming and rising for five centuries. Some creatures of the deep will have less room to breathe.

LONDON, 22 April, 2021 − Even if humans stopped all use of fossil fuels immediately, and drastically reduced greenhouse gas emissions, the oceans would go on warming. And as the waters warmed, their burden of dissolved oxygen would continue to dwindle, stifling many creatures of the deep.

This could continue for another 500 years, at the end of which oxygen loss in the seas would have multiplied fourfold. Since oxygen is vital to almost all complex life on Earth, and since the ocean − covering 70% of the globe and reaching in places to depths of almost 11 kilometres − provides by far the oldest and biggest breathing space for living things, that could commit many creatures to a slow, stifling end, according to a new study in the journal Nature Communications.

Both oxygen and carbon dioxide are soluble in seawater. The colder the water, the greater the capacity for dissolved gases, which ultimately is why polar seas are vastly and massively richer in life than tropical waters. But the latest study of the long-term consequences of carbon dioxide emissions offers a bleak picture for the future.

As the planet has warmed, so have the seas. As the greenhouse gas burden of the atmosphere has increased, so has the acidity of the ocean. And as the ocean waters have warmed, the levels of dissolved oxygen have fallen.

In the last 50 years, the ocean has on average lost 2% of its dissolved oxygen. That’s an average figure. In some parts of the water column, the loss has been much higher, directly as a consequence of global warming. And this loss will continue until around 2650.

“The deep ocean appears committed to turning into an as-yet-unrecognised area where the slogan ‘If you can’t breathe, nothing else matters’ will become reality for many centuries to come”

Andreas Oschlies of the Geomar Helmholtz Centre for Ocean Research in Kiel in Germany used a climate model of the Earth system to work out what would happen to the ocean in the long term if all carbon dioxide emissions stopped right now.

He says: “The results show that even in this extreme scenario, the oxygen depletion will continue for centuries, more than quadrupling the oxygen loss we have seen to date in the ocean.”

Most of this loss will be at depths of 2000 metres or more, partly because ocean circulation is becoming more sluggish in response to climate change. So the deepest parts of the ocean could lose more than a tenth of all the oxygen it once held before the launch of the Industrial Revolution and the accelerated use of coal, oil and gas to drive national economies. And that would be bad news for the creatures that swim and replicate at depth: some of them could face a decline of up to 25%.

And if nations could achieve the impossible and halt all emissions now, surface air temperatures would stabilise rapidly. But the oceans would go on absorbing the extra carbon dioxide already in the atmosphere. Between now and 2650, according to the calculations of Professor Oschlies, the ocean would go on absorbing another 720 billion tonnes of the gas. This is larger than all the CO2 the oceans have taken up till now: an estimated 634 billion tonnes.

Too little air

But the atmospheric heat the oceans will absorb in the next five centuries is likely to be three times the heat already absorbed up till now. This warmth alone − because warm water is less dense than cold water − will mean another 16cms of unavoidable sea level rise. And as the waters warm, the oxygen levels in that water will continue to diminish: by 2650 it will have fallen by 7.4% compared with oxygen levels a century or more ago. And this is more than three times the loss that has already happened.

Those sea creatures that had adapted over a million years to one set of oxygen levels are going to face a problem: there won’t be enough oxygen dissolved in the deep seas to support all of them. Some regions of the ocean will slowly become “dead zones”.

Oceanography is a costly science, and most of the ocean is unexplored: humans have mapped the surface and plundered the coastal waters but have yet to explore the depths in much detail over vast tracts of the planet’s largest living room.

There’s a lot more research to be done, before researchers can be sure of the ways in which human action is about to irrevocably change the submarine world. But the outlook so far is ominous.

Professor Oschlies warns: “The deep ocean appears committed to turning into an as-yet-unrecognised area where the slogan of the American Lung Association − ‘If you can’t breathe, nothing else matters’ − will become reality for many centuries to come.” − Climate News Network

Protect fish to increase catches − and cut carbon

There is a clear way to get more value from the seas: protect fish. New research confirms an old argument.

LONDON, 25 March, 2021 − Scientists have identified a sure way towards more profitable fishing: don’t do it. Protect fish and leave as much of the seas as possible untouched.

To convert the right stretches of the blue planet into marine sanctuaries would actually deliver bigger hauls than any uncontrolled harvests could promise. It could also protect marine wildlife and reduce greenhouse gas emissions to the atmosphere.

“Ocean life has been declining worldwide because of overfishing, habitat destruction and climate change. Yet only 7% of the ocean is currently under some kind of protection,” said Enric Sala, of the Pristine Seas project at the National Geographic Society.

“In this study, we’ve pioneered a new way to identify the places that − if protected − will boost food production and safeguard marine life, all while reducing carbon emissions,” Dr Sala said.

“It’s clear that humanity and the economy will benefit from a healthier ocean. And we can realise those benefits quickly if countries work together to protect at least 30% of the ocean by 2030.”

No to exploitation

He and 25 other scientists from the US, Canada, France, Germany and Australia report in the journal Nature that they have devised a planning framework and identified regions of ocean that would benefit most from status as Marine Protected Areas, or MPAs.

Right now only around 2.7% of the high seas are fully or highly protected, and in all 7% have been designated or proposed as suitable for such status.

The scientists argue that to safeguard their proposed areas could offer safety for 80% of marine species, ultimately add eight million tonnes more to the global catch than any uncontrolled trawling could offer, and prevent the release of more than a billion tonnes of carbon dioxide a year − simply by preventing disturbance of the sea floor.

They see an enormous gain if even 21% of the ocean is protected, and they want to see 30% of the global ocean undisturbed and valued as a conservation resource by the year 2030.

The argument that humans can profit more from conserving the wilderness than by ruthlessly exploiting it sounds radical. But it has been made again and again.

“We’ve pioneered a new way to identify the places that − if protected − will boost food production and safeguard marine life, all while reducing carbon emissions”

On land, separate research teams have found repeatedly that forests and wetlands deliver a higher net return in the long term, and to the greatest number of people, than mining, felling or farming can offer.

And it has been the same story afloat: world fish catches would benefit from protected areas; fishing itself would become more dangerous and
with lower returns in a regime of uncontrolled global climate change; and a reduction in the rate of global heating would pay off in richer marine harvests.

Diplomats and scientists from 190 nations will meet in Kunming in China this year for a conference of the UN Convention on Biological Diversity. The US, Canada, the European Commission and other nations have committed to the goal of protecting 30% of the planet by 2030.

But the implication of the latest study is that such declarations are only as good as the effort to realise them that sponsor nations are prepared to make. Most of the proposed protected stretches of sea are within the 200-mile exclusive economic zones of coastal nations; others − the Mid-Atlantic Ridge, for instance, and the Southwest Indian Ridge between South Africa and Antarctica, are governed by international law.

The researchers’ proposals would require a ban on bottom trawling, in which heavy nets scour the submarine ooze. The carbon dioxide released into the ocean from this practice alone is higher than emissions from global aviation; higher even than most countries’ annual carbon emissions.

More is worse

“The ocean floor is the world’s largest carbon storehouse. If we’re to succeed in stopping global warming, we must leave the carbon-rich seabed undisturbed,” said Trisha Atwood of Utah State University, one of the authors.

“Yet every day, we are trawling the seafloor, depleting its biodiversity and mobilising millennia-old carbon and thus exacerbating climate change. Our findings about the climate impacts of bottom trawling will make the activities on the ocean’s seabed hard to ignore in climate plans going forward.”

The overall argument the researchers put to the world’s great fishing nations is a simple one: the worst enemy of successful fishing is overfishing.

“It’s simple: When overfishing and other damaging activities cease, marine life bounces back,” said Reniel Cabral of the University of California Santa Barbara, another of the signatories.

“After protections are put in place, the diversity and abundance of marine life increase over time, with measurable recovery within reserves occurring in as little as three years. Target species and large predators come back, and entire ecosystems are restored within MPAs. With time, the ocean can heal itself and again provide services to humankind.” − Climate News Network

There is a clear way to get more value from the seas: protect fish. New research confirms an old argument.

LONDON, 25 March, 2021 − Scientists have identified a sure way towards more profitable fishing: don’t do it. Protect fish and leave as much of the seas as possible untouched.

To convert the right stretches of the blue planet into marine sanctuaries would actually deliver bigger hauls than any uncontrolled harvests could promise. It could also protect marine wildlife and reduce greenhouse gas emissions to the atmosphere.

“Ocean life has been declining worldwide because of overfishing, habitat destruction and climate change. Yet only 7% of the ocean is currently under some kind of protection,” said Enric Sala, of the Pristine Seas project at the National Geographic Society.

“In this study, we’ve pioneered a new way to identify the places that − if protected − will boost food production and safeguard marine life, all while reducing carbon emissions,” Dr Sala said.

“It’s clear that humanity and the economy will benefit from a healthier ocean. And we can realise those benefits quickly if countries work together to protect at least 30% of the ocean by 2030.”

No to exploitation

He and 25 other scientists from the US, Canada, France, Germany and Australia report in the journal Nature that they have devised a planning framework and identified regions of ocean that would benefit most from status as Marine Protected Areas, or MPAs.

Right now only around 2.7% of the high seas are fully or highly protected, and in all 7% have been designated or proposed as suitable for such status.

The scientists argue that to safeguard their proposed areas could offer safety for 80% of marine species, ultimately add eight million tonnes more to the global catch than any uncontrolled trawling could offer, and prevent the release of more than a billion tonnes of carbon dioxide a year − simply by preventing disturbance of the sea floor.

They see an enormous gain if even 21% of the ocean is protected, and they want to see 30% of the global ocean undisturbed and valued as a conservation resource by the year 2030.

The argument that humans can profit more from conserving the wilderness than by ruthlessly exploiting it sounds radical. But it has been made again and again.

“We’ve pioneered a new way to identify the places that − if protected − will boost food production and safeguard marine life, all while reducing carbon emissions”

On land, separate research teams have found repeatedly that forests and wetlands deliver a higher net return in the long term, and to the greatest number of people, than mining, felling or farming can offer.

And it has been the same story afloat: world fish catches would benefit from protected areas; fishing itself would become more dangerous and
with lower returns in a regime of uncontrolled global climate change; and a reduction in the rate of global heating would pay off in richer marine harvests.

Diplomats and scientists from 190 nations will meet in Kunming in China this year for a conference of the UN Convention on Biological Diversity. The US, Canada, the European Commission and other nations have committed to the goal of protecting 30% of the planet by 2030.

But the implication of the latest study is that such declarations are only as good as the effort to realise them that sponsor nations are prepared to make. Most of the proposed protected stretches of sea are within the 200-mile exclusive economic zones of coastal nations; others − the Mid-Atlantic Ridge, for instance, and the Southwest Indian Ridge between South Africa and Antarctica, are governed by international law.

The researchers’ proposals would require a ban on bottom trawling, in which heavy nets scour the submarine ooze. The carbon dioxide released into the ocean from this practice alone is higher than emissions from global aviation; higher even than most countries’ annual carbon emissions.

More is worse

“The ocean floor is the world’s largest carbon storehouse. If we’re to succeed in stopping global warming, we must leave the carbon-rich seabed undisturbed,” said Trisha Atwood of Utah State University, one of the authors.

“Yet every day, we are trawling the seafloor, depleting its biodiversity and mobilising millennia-old carbon and thus exacerbating climate change. Our findings about the climate impacts of bottom trawling will make the activities on the ocean’s seabed hard to ignore in climate plans going forward.”

The overall argument the researchers put to the world’s great fishing nations is a simple one: the worst enemy of successful fishing is overfishing.

“It’s simple: When overfishing and other damaging activities cease, marine life bounces back,” said Reniel Cabral of the University of California Santa Barbara, another of the signatories.

“After protections are put in place, the diversity and abundance of marine life increase over time, with measurable recovery within reserves occurring in as little as three years. Target species and large predators come back, and entire ecosystems are restored within MPAs. With time, the ocean can heal itself and again provide services to humankind.” − Climate News Network

World’s coastal cities face risk from land and sea

As the tides rise ever higher, the world’s coastal cities carry on sinking. It’s a recipe for civic catastrophe.

LONDON, 15 March, 2021 − Citizens of many of the world’s coastal cities have even more to fear from rising tides. As ocean levels swell, in response to rising temperatures and melting glaciers, the land on which those cities are built is sinking.

This means that although, worldwide, oceans are now 2.6mm higher every year in response to climate change, many citizens of some of the world’s great delta cities face the risk of an average sea level rise of up to almost 10mm a year. Both the rising waters and the sinking city streets are ultimately a consequence of human actions.

Humans have not only burned fossil fuels to alter the planet’s atmosphere and raise global temperatures, they have also pumped water from the ground below the cities. They have raised massive structures on riverine sediments; they have pumped oil and gas from offshore, and they have dammed rivers to slow the flow of new sediments.

And because of such steps, some of the world’s great cities have been steadily going downhill. Tokyo in Japan has subsided by four metres in the course of the 20th century. Shanghai in China, Bangkok in Thailand, New Orleans in the US and Djakarta on the island of Java in Indonesia have all sunk by between two and three metres in the last 100 years.

Now a new study in the journal Nature Climate Change has found that 58% of the world’s coastal citizens live on soil and bedrock that is collapsing beneath their feet. Fewer than 1% are settled on terrain that is uplifting. Most are exposed to possible relative sea level rises of between 7.8mm and 9.9mm a year.

“The message to governments and local authorities is: start thinking about subsidence now”

“We wanted to look at the big picture globally, to better understand the impact of global sea level rise combined with measurements of sinking land,” said Robert Nicholls, of the University of East Anglia in the UK.

“We found that coastal populations live with sea level rise at three and four times the global average and that the impacts of sea level rise being experienced today are much larger than the global numbers being reported by the Intergovernmental Panel on Climate Change.”

So the message to governments and local authorities is: start thinking about subsidence now.

Coastal flooding has been a source of increasing alarm for a decade. Eight years ago, researchers warned that by 2050 coastal floods could be costing the world US$1 trillion a year.

Since then individual research teams have been looking at the risks from extremes of rainfall, storm surges, shifts in ocean temperatures and currents, to find that by the century’s end what had once been once-a-century events could become 10 times more frequent.

Faulty readings

And yet another group has questioned the assumptions on which sea and coastal land heights are based. Many of the estimates have been confirmed by satellite radar topography measurements, but these in turn are based on reflections from the first surface the radar signal touches. If it falls on bare farmland, it will be accurate. If the signal hits buildings or tree tops, then the measurements might be misleading: the land surface could be much lower.

Other research teams have looked at rates of melting in Greenland and the Antarctic to warn that previous forecasts could prove to have been underestimates: by the end of the century, oceans could have risen by as much as two metres in a worst case scenario. Once again, how bad things turn out will depend on what steps humans take now.

So, like all the research that has preceded it, this last study confirms that, however bad things looked before, they now look even more alarming. The point of such research, of course, is to help governments prepare for the worst. Tokyo, Shanghai and Bangkok have already slowed the extraction of groundwater. Other nations must consider other solutions.

“One of the main reasons that Jakarta, the capital city of Indonesia, is being moved to Borneo is because the city is sinking due to groundwater extraction from shallow wells,” said Professor Nicholls.

“We hope that our analysis improves the understanding of how sea level rise and subsidence are hand-in-hand for science and coastal management policy worldwide. Jakarta might be just the beginning.” − Climate News Network

As the tides rise ever higher, the world’s coastal cities carry on sinking. It’s a recipe for civic catastrophe.

LONDON, 15 March, 2021 − Citizens of many of the world’s coastal cities have even more to fear from rising tides. As ocean levels swell, in response to rising temperatures and melting glaciers, the land on which those cities are built is sinking.

This means that although, worldwide, oceans are now 2.6mm higher every year in response to climate change, many citizens of some of the world’s great delta cities face the risk of an average sea level rise of up to almost 10mm a year. Both the rising waters and the sinking city streets are ultimately a consequence of human actions.

Humans have not only burned fossil fuels to alter the planet’s atmosphere and raise global temperatures, they have also pumped water from the ground below the cities. They have raised massive structures on riverine sediments; they have pumped oil and gas from offshore, and they have dammed rivers to slow the flow of new sediments.

And because of such steps, some of the world’s great cities have been steadily going downhill. Tokyo in Japan has subsided by four metres in the course of the 20th century. Shanghai in China, Bangkok in Thailand, New Orleans in the US and Djakarta on the island of Java in Indonesia have all sunk by between two and three metres in the last 100 years.

Now a new study in the journal Nature Climate Change has found that 58% of the world’s coastal citizens live on soil and bedrock that is collapsing beneath their feet. Fewer than 1% are settled on terrain that is uplifting. Most are exposed to possible relative sea level rises of between 7.8mm and 9.9mm a year.

“The message to governments and local authorities is: start thinking about subsidence now”

“We wanted to look at the big picture globally, to better understand the impact of global sea level rise combined with measurements of sinking land,” said Robert Nicholls, of the University of East Anglia in the UK.

“We found that coastal populations live with sea level rise at three and four times the global average and that the impacts of sea level rise being experienced today are much larger than the global numbers being reported by the Intergovernmental Panel on Climate Change.”

So the message to governments and local authorities is: start thinking about subsidence now.

Coastal flooding has been a source of increasing alarm for a decade. Eight years ago, researchers warned that by 2050 coastal floods could be costing the world US$1 trillion a year.

Since then individual research teams have been looking at the risks from extremes of rainfall, storm surges, shifts in ocean temperatures and currents, to find that by the century’s end what had once been once-a-century events could become 10 times more frequent.

Faulty readings

And yet another group has questioned the assumptions on which sea and coastal land heights are based. Many of the estimates have been confirmed by satellite radar topography measurements, but these in turn are based on reflections from the first surface the radar signal touches. If it falls on bare farmland, it will be accurate. If the signal hits buildings or tree tops, then the measurements might be misleading: the land surface could be much lower.

Other research teams have looked at rates of melting in Greenland and the Antarctic to warn that previous forecasts could prove to have been underestimates: by the end of the century, oceans could have risen by as much as two metres in a worst case scenario. Once again, how bad things turn out will depend on what steps humans take now.

So, like all the research that has preceded it, this last study confirms that, however bad things looked before, they now look even more alarming. The point of such research, of course, is to help governments prepare for the worst. Tokyo, Shanghai and Bangkok have already slowed the extraction of groundwater. Other nations must consider other solutions.

“One of the main reasons that Jakarta, the capital city of Indonesia, is being moved to Borneo is because the city is sinking due to groundwater extraction from shallow wells,” said Professor Nicholls.

“We hope that our analysis improves the understanding of how sea level rise and subsidence are hand-in-hand for science and coastal management policy worldwide. Jakarta might be just the beginning.” − Climate News Network

Weakening Gulf Stream may disrupt world weather

The Gulf Stream is growing feebler, the Arctic seas are gaining fresh water. Together they could affect the world’s weather.

LONDON, 2 March, 2021 − The Atlantic Conveyer, otherwise the Gulf Stream − that great flow of surface water pouring northwards that overturns in the Arctic and heads south again at great depth − is now weaker than at any point in the last 1,000 years, European scientists report.

And in a second, separate but related study, researchers have found that the Beaufort Sea, in the Arctic, has gained two-fifths more fresh water in the last 20 years: water that could flow into the Atlantic to affect the Conveyor, and with it, climatic conditions.

Scientists call it the Atlantic Meridional Overturning Circulation or just AMOC. Europeans know it as the Gulf Stream: the current that conveys tropic warmth to their coasts and keeps Britain and Western Europe at a temperature several degrees higher than latitude alone might dictate.

And for years, oceanographers and climate scientists have been observing a slowing of the flow, by as much as 15%. But direct measurement of the great current began only relatively recently in 2004: researchers needed to know whether the slowdown was part of a natural cycle, or a consequence of climate change driven by global heating.

Now they know a little more. European researchers report in Nature Geoscience that they looked for evidence of ocean circulation shifts in what they call “proxy evidence”: the story of climate change told by tree growth rings, ice cores, ocean sediments, corals and historical records, including naval logbooks.

The combined evidence of temperature patterns, the sizes of particles of ocean floor sediment and the salinity and density of sub-surface water helps build up a picture of the Atlantic current for the last 1,600 years.

“The Gulf Stream System moves nearly 20 million cubic meters of water per second, almost a hundred times the Amazon flow”

The verdict? Up to the 19th century, ocean currents were stable. The flow is now more sluggish than at any time in the last millennium.

This is roughly what climate models have predicted: the warm salty water moves north, cools, becomes more dense, sinks to the deep and flows back south. But the Arctic has begun to warm, Greenland to melt, and the flow of fresh water into the northern seas to intensify.

Since the flow is driven by the difference in temperatures, any change in the regional thermometer will play back into the rate of flow. And any extra arrival of fresh water could further slow the overturning circulation.

“The Gulf Stream system works like a giant conveyor belt, carrying warm surface water from the equator up north, and sending cold, low-salinity deep water back down south. It moves nearly 20 million cubic meters of water per second, almost a hundred times the Amazon flow,” said Stefan Rahmstorf, of the Potsdam Institute for Climate Impact Research, in Germany, one of the authors.

“For the first time, we have combined a range of previous studies and found they provide a consistent picture of the AMOC evolution over the past 1600 years. The study results suggest that it has been relatively stable until the late 19th century.

“With the end of the Little Ice Age in about 1850, the ocean currents began to decline, with a second, more drastic decline following since the mid-20th century.”

Outcome awaited

The change could have ominous consequences for European weather systems: it could also deliver more intense coastal flooding to the US eastern seaboard. If the current continues to weaken, the consequences could be catastrophic.

Which is why a new study in Nature Communications matters so much. US researchers tracked the flow of fresh water from the Beaufort Sea − melt water from glaciers, rivers and disappearing Arctic sea ice − through the Canadian Archipelago and into the Labrador Sea.

Arctic water is fresher than Atlantic water, and richer in nutrients. But this extra volume, measured at a total of 23,300 cubic kilometres, could also affect the rate of flow of the overturning circulation. That is because relatively fresh water is less dense than saline water, and tends to float on top.

Quite what role it could play is uncertain: the message is that, sooner or later, it will escape into the North Atlantic. Then the world will find out.

“People have already spent a lot of time studying why the Beaufort Sea fresh water has gotten so high in the past few decades,” said Jiaxu Zhang,  of the Los Alamos National Laboratory, first author. “But they rarely care where the freshwater goes, and we think that’s a much more important problem.” − Climate News Network

The Gulf Stream is growing feebler, the Arctic seas are gaining fresh water. Together they could affect the world’s weather.

LONDON, 2 March, 2021 − The Atlantic Conveyer, otherwise the Gulf Stream − that great flow of surface water pouring northwards that overturns in the Arctic and heads south again at great depth − is now weaker than at any point in the last 1,000 years, European scientists report.

And in a second, separate but related study, researchers have found that the Beaufort Sea, in the Arctic, has gained two-fifths more fresh water in the last 20 years: water that could flow into the Atlantic to affect the Conveyor, and with it, climatic conditions.

Scientists call it the Atlantic Meridional Overturning Circulation or just AMOC. Europeans know it as the Gulf Stream: the current that conveys tropic warmth to their coasts and keeps Britain and Western Europe at a temperature several degrees higher than latitude alone might dictate.

And for years, oceanographers and climate scientists have been observing a slowing of the flow, by as much as 15%. But direct measurement of the great current began only relatively recently in 2004: researchers needed to know whether the slowdown was part of a natural cycle, or a consequence of climate change driven by global heating.

Now they know a little more. European researchers report in Nature Geoscience that they looked for evidence of ocean circulation shifts in what they call “proxy evidence”: the story of climate change told by tree growth rings, ice cores, ocean sediments, corals and historical records, including naval logbooks.

The combined evidence of temperature patterns, the sizes of particles of ocean floor sediment and the salinity and density of sub-surface water helps build up a picture of the Atlantic current for the last 1,600 years.

“The Gulf Stream System moves nearly 20 million cubic meters of water per second, almost a hundred times the Amazon flow”

The verdict? Up to the 19th century, ocean currents were stable. The flow is now more sluggish than at any time in the last millennium.

This is roughly what climate models have predicted: the warm salty water moves north, cools, becomes more dense, sinks to the deep and flows back south. But the Arctic has begun to warm, Greenland to melt, and the flow of fresh water into the northern seas to intensify.

Since the flow is driven by the difference in temperatures, any change in the regional thermometer will play back into the rate of flow. And any extra arrival of fresh water could further slow the overturning circulation.

“The Gulf Stream system works like a giant conveyor belt, carrying warm surface water from the equator up north, and sending cold, low-salinity deep water back down south. It moves nearly 20 million cubic meters of water per second, almost a hundred times the Amazon flow,” said Stefan Rahmstorf, of the Potsdam Institute for Climate Impact Research, in Germany, one of the authors.

“For the first time, we have combined a range of previous studies and found they provide a consistent picture of the AMOC evolution over the past 1600 years. The study results suggest that it has been relatively stable until the late 19th century.

“With the end of the Little Ice Age in about 1850, the ocean currents began to decline, with a second, more drastic decline following since the mid-20th century.”

Outcome awaited

The change could have ominous consequences for European weather systems: it could also deliver more intense coastal flooding to the US eastern seaboard. If the current continues to weaken, the consequences could be catastrophic.

Which is why a new study in Nature Communications matters so much. US researchers tracked the flow of fresh water from the Beaufort Sea − melt water from glaciers, rivers and disappearing Arctic sea ice − through the Canadian Archipelago and into the Labrador Sea.

Arctic water is fresher than Atlantic water, and richer in nutrients. But this extra volume, measured at a total of 23,300 cubic kilometres, could also affect the rate of flow of the overturning circulation. That is because relatively fresh water is less dense than saline water, and tends to float on top.

Quite what role it could play is uncertain: the message is that, sooner or later, it will escape into the North Atlantic. Then the world will find out.

“People have already spent a lot of time studying why the Beaufort Sea fresh water has gotten so high in the past few decades,” said Jiaxu Zhang,  of the Los Alamos National Laboratory, first author. “But they rarely care where the freshwater goes, and we think that’s a much more important problem.” − Climate News Network

Rising sea levels may make some airports unusable

High flyers could soon have a problem with high water. Rising sea levels could one day shut down airports.

LONDON, 3 February, 2021 − Passengers, prepare for splashdown. Take-off may have to wait for low tide. By 2100, thanks to rising sea levels, around 100 of the world’s airports could be below mean sea level and at least 364 will be vulnerable to flooding.

And that’s assuming the world’s nations keep a promise made in 2015 and confine global heating to no more than 2°C above the average maintained for most of human history. If humans go on burning fossil fuels and clearing forests at the present rate, then at least 572 of the world’s airports could be at risk of flooding from extreme tides, according to a new study in the journal Climate Risk Management.

These things have already happened: in 2018 a typhoon storm surge inundated Kansai International Airport in Osaka Bay, Japan. Superstorm Sandy in 2012 closed New York City’s La Guardia Airport for three days. One-tenth of the planet’s population lives on coastlines less than 10 metres above sea level.

Airports grow up around the great cities: they require flat land and a clear flight path. Coastal flood plains, wetlands and reclaimed land provide exactly that.

Serious risk

“These coastal airports are disproportionately important to the global airline network, and by 2100 between 10% and 20% of all routes will be at risk of disruption,” said Richard Dawson, an engineer at Newcastle University in the United Kingdom. “Sea level rise therefore poses a serious risk to global passenger and freight movements, with considerable cost of damage and disruption.”

He and a colleague looked at the world’s 14,000 airports and helicopter pads to identify 1,238 airports in what geographers call low elevation coastal zones: that is, down by the seaside. Of these, 199, serving 3,436 routes, were in the US; China had 30 airports serving 2,333 routes.

They found that just 20 airports at risk handled more than 800 million passengers in 2018 − approaching a fifth of the world’s passenger traffic that year − and nearly 16 million tonnes of cargo: one-fourth of all the world’s air freight that year. They then started looking at what climate change could do to all that business.

Even before the shutdown of traffic because of the global pandemic, the world’s airlines had been feeling the heat. Research teams have confirmed that ever higher global temperatures mean more atmospheric turbulence at altitude; that wind speed changes will slow flights and raise costs; that extremes of heat could even close airport runways and delay flights for extended periods.

“These coastal airports are disproportionately important to the global airline network, and by 2100 between 10% and 20% of all routes will be at risk of disruption”

Now Professor Dawson and his colleague have compiled a table of hazard rankings for flooded airstrips under a range of climate change scenarios.

Right now, 269 of the world’s airports are at some risk of coastal flooding. This number must rise: by how much, and at what cost, depends on what actions the world takes. But the researchers calculate that by 2100 the risk of disruption could increase 17-fold, or even 69-fold. And because so many important airports are already at or near sea level, up to a fifth of all the world’s routes will be at risk.

And that means higher costs for flood protection, or action to raise airport sites, or relocation. The choice is to adapt or, quite literally, to go under.

“The cost of adaptation will be modest in the context of global infrastructure expenditure,” Professor Dawson said. “However, in some locations the rate of sea level rise, limited economic resources or space for alternative locations will make some airports unviable.” − Climate News Network

High flyers could soon have a problem with high water. Rising sea levels could one day shut down airports.

LONDON, 3 February, 2021 − Passengers, prepare for splashdown. Take-off may have to wait for low tide. By 2100, thanks to rising sea levels, around 100 of the world’s airports could be below mean sea level and at least 364 will be vulnerable to flooding.

And that’s assuming the world’s nations keep a promise made in 2015 and confine global heating to no more than 2°C above the average maintained for most of human history. If humans go on burning fossil fuels and clearing forests at the present rate, then at least 572 of the world’s airports could be at risk of flooding from extreme tides, according to a new study in the journal Climate Risk Management.

These things have already happened: in 2018 a typhoon storm surge inundated Kansai International Airport in Osaka Bay, Japan. Superstorm Sandy in 2012 closed New York City’s La Guardia Airport for three days. One-tenth of the planet’s population lives on coastlines less than 10 metres above sea level.

Airports grow up around the great cities: they require flat land and a clear flight path. Coastal flood plains, wetlands and reclaimed land provide exactly that.

Serious risk

“These coastal airports are disproportionately important to the global airline network, and by 2100 between 10% and 20% of all routes will be at risk of disruption,” said Richard Dawson, an engineer at Newcastle University in the United Kingdom. “Sea level rise therefore poses a serious risk to global passenger and freight movements, with considerable cost of damage and disruption.”

He and a colleague looked at the world’s 14,000 airports and helicopter pads to identify 1,238 airports in what geographers call low elevation coastal zones: that is, down by the seaside. Of these, 199, serving 3,436 routes, were in the US; China had 30 airports serving 2,333 routes.

They found that just 20 airports at risk handled more than 800 million passengers in 2018 − approaching a fifth of the world’s passenger traffic that year − and nearly 16 million tonnes of cargo: one-fourth of all the world’s air freight that year. They then started looking at what climate change could do to all that business.

Even before the shutdown of traffic because of the global pandemic, the world’s airlines had been feeling the heat. Research teams have confirmed that ever higher global temperatures mean more atmospheric turbulence at altitude; that wind speed changes will slow flights and raise costs; that extremes of heat could even close airport runways and delay flights for extended periods.

“These coastal airports are disproportionately important to the global airline network, and by 2100 between 10% and 20% of all routes will be at risk of disruption”

Now Professor Dawson and his colleague have compiled a table of hazard rankings for flooded airstrips under a range of climate change scenarios.

Right now, 269 of the world’s airports are at some risk of coastal flooding. This number must rise: by how much, and at what cost, depends on what actions the world takes. But the researchers calculate that by 2100 the risk of disruption could increase 17-fold, or even 69-fold. And because so many important airports are already at or near sea level, up to a fifth of all the world’s routes will be at risk.

And that means higher costs for flood protection, or action to raise airport sites, or relocation. The choice is to adapt or, quite literally, to go under.

“The cost of adaptation will be modest in the context of global infrastructure expenditure,” Professor Dawson said. “However, in some locations the rate of sea level rise, limited economic resources or space for alternative locations will make some airports unviable.” − Climate News Network

Human rubbish is smothering the planet’s oceans

In a throwaway world garbage may be unseen, but not gone. Human rubbish is everywhere, from ocean abyss to coastal mud.

LONDON, 29 January, 2021 − In the next 30 years, an estimated three billion metric tonnes of human rubbish − everything from abandoned trawl nets to plastic bottles, from broken teacups to tins of toxin − could find its way into the sea, to defile the ocean floor.

One recent survey in the Strait of Messina, the seaway that separates Italy and Sicily, measured this detritus at concentrations of between 121,000 and 1.3 million items per square kilometre trapped in submarine canyons.

In seabed fissures off Portugal, bits of human litter large enough to identify have been counted at rates of 11,000 per sq km. Off the Ryukyu Islands far from mainland Japan, divers and remotely operated vehicles have made estimates of up to 71,000 items per sq km.

There is more and worse lying on other parts of the seabed. An estimated one million tonnes of chemical weaponry could be scattered about the planet’s oceans. The North Sea floor could be host to 1.3 million tonnes of conventional and chemical weapons; the Baltic enfolds and flows over 385,00 tonnes of dropped bombs, grenades, torpedoes, landmines and other weaponry.

“As humans, we have little or no care at all to prevent litter from accumulating everywhere”

And, says a new study in the journal Environmental Research Letters, this conversion of sea floor to careless landfill site creates problems for at least 693 marine species that so far have been observed to “interact” with marine debris: eat it, get caught in it, grow on it. Of these species, around one in six are in some degree endangered.

This list of sea creatures includes 93 kinds of invertebrate, 89 fish, 83 birds, 38 mammals and all species of sea turtle. So many fish now become ensnared in abandoned and derelict fishing gear that they are known as “ghost catches.”

Across the Asia-Pacific region, an estimated 11.1 billion bits of plastic bigger than 25mm could be entangled in the coral reefs. This problem of marine pollution goes far beyond the concern over plastic pollution of the planet’s seas and shores, from pole to pole, and is now found even in marine tissues.

Much of the previous concern has been about the presence of microfibres and small particles of polymer material now found everywhere. But the new study by European scientists tries to address the more obvious problem of these larger items − generally larger than 25mms − of all kinds of detritus, including plastic denser than water and ultimately destined to reach the seabed.

Poor management

The researchers want to try to find standard ways to measure the levels of waste, map its concentrations accurately, identify all the sources of refuse and classify the most problematic kinds: the toxic waste, the heavy metals and radioactive substances, the pharmaceuticals. They also urge international co-operation, and policies designed to discourage marine discharges and to clear up stretches of the sea floor.

“Marine litter has reached the most remote places in the ocean, even the least − or never − frequented by our species and not yet mapped by science,” said Miquel Canals of the University of Barcelona, who led the study.

“In order to correct something bad, we must attack its cause. And the cause of the accumulation of waste on the coasts, seas and oceans , and all over the planet, is the excess waste generation and spillage in the environment, and poor or insufficient management practices.

“As humans, we have little or no care at all to prevent litter from accumulating everywhere.” − Climate News Network

In a throwaway world garbage may be unseen, but not gone. Human rubbish is everywhere, from ocean abyss to coastal mud.

LONDON, 29 January, 2021 − In the next 30 years, an estimated three billion metric tonnes of human rubbish − everything from abandoned trawl nets to plastic bottles, from broken teacups to tins of toxin − could find its way into the sea, to defile the ocean floor.

One recent survey in the Strait of Messina, the seaway that separates Italy and Sicily, measured this detritus at concentrations of between 121,000 and 1.3 million items per square kilometre trapped in submarine canyons.

In seabed fissures off Portugal, bits of human litter large enough to identify have been counted at rates of 11,000 per sq km. Off the Ryukyu Islands far from mainland Japan, divers and remotely operated vehicles have made estimates of up to 71,000 items per sq km.

There is more and worse lying on other parts of the seabed. An estimated one million tonnes of chemical weaponry could be scattered about the planet’s oceans. The North Sea floor could be host to 1.3 million tonnes of conventional and chemical weapons; the Baltic enfolds and flows over 385,00 tonnes of dropped bombs, grenades, torpedoes, landmines and other weaponry.

“As humans, we have little or no care at all to prevent litter from accumulating everywhere”

And, says a new study in the journal Environmental Research Letters, this conversion of sea floor to careless landfill site creates problems for at least 693 marine species that so far have been observed to “interact” with marine debris: eat it, get caught in it, grow on it. Of these species, around one in six are in some degree endangered.

This list of sea creatures includes 93 kinds of invertebrate, 89 fish, 83 birds, 38 mammals and all species of sea turtle. So many fish now become ensnared in abandoned and derelict fishing gear that they are known as “ghost catches.”

Across the Asia-Pacific region, an estimated 11.1 billion bits of plastic bigger than 25mm could be entangled in the coral reefs. This problem of marine pollution goes far beyond the concern over plastic pollution of the planet’s seas and shores, from pole to pole, and is now found even in marine tissues.

Much of the previous concern has been about the presence of microfibres and small particles of polymer material now found everywhere. But the new study by European scientists tries to address the more obvious problem of these larger items − generally larger than 25mms − of all kinds of detritus, including plastic denser than water and ultimately destined to reach the seabed.

Poor management

The researchers want to try to find standard ways to measure the levels of waste, map its concentrations accurately, identify all the sources of refuse and classify the most problematic kinds: the toxic waste, the heavy metals and radioactive substances, the pharmaceuticals. They also urge international co-operation, and policies designed to discourage marine discharges and to clear up stretches of the sea floor.

“Marine litter has reached the most remote places in the ocean, even the least − or never − frequented by our species and not yet mapped by science,” said Miquel Canals of the University of Barcelona, who led the study.

“In order to correct something bad, we must attack its cause. And the cause of the accumulation of waste on the coasts, seas and oceans , and all over the planet, is the excess waste generation and spillage in the environment, and poor or insufficient management practices.

“As humans, we have little or no care at all to prevent litter from accumulating everywhere.” − Climate News Network

Ocean research plan seeks to preserve seas’ wealth

A decade of ocean research is about to begin to try to save the planet’s richest habitat from human destruction.

LONDON, 9 December, 2020 − Humans need urgently to invest in ocean research and protection. In return, the ocean could repay them handsomely, by soaking up atmospheric carbon, delivering huge amounts of renewable energy, providing six times more sustainable seafood, creating millions of jobs and generating trillions in economic benefits.

The oceans cover 70% of the planet but, a trio of scientists warn in the journal Nature, “for much too long, the ocean has been out of sight, out of mind and out of luck.”

From the margins of the coast to the deepest seas, the oceans’ habitats and the living creatures in them have been threatened by excessive and destructive fishing, they say.

“Unsustainable development along coastlines is destroying coral reefs, seagrass beds, salt marshes and mangrove forests. These house biodiversity, sequester carbon, provide nurseries for fish and buffer coasts against storm surges.

Separate approaches inadequate

Plastics and nutrients washed from the land are also killing wildlife. All of these threats erode the capacity of the ocean to provide nutritious food, jobs, medicines and pharmaceuticals as well as regulate the climate.”

But something can be done. A new report − commissioned by Norway, Palau, 12 other nations and a UN envoy, collectively responsible for two-fifths of the world’s coastlines, almost a third of the exclusive economic zones and a fifth of the world’s shipping − argues that it is not enough for individual nations to manage their sectors or confront challenging issues separately. The largest and deepest continuous living space on the planet demands something more.

The report finds that − if the world co-operated in an holistic approach to care for the oceans, and protected at least 30% of them − then by 2050 the deep blue sea could account for 20% of the carbon emission reductions needed to match the Paris climate agreement target of no more than 1.5°C warming above pre-industrial levels.

Such an initiative could exploit the ocean to provide 40 times the renewable energy generated worldwide in 2018. It could provide six times the sustainable seafood, create 12 million jobs and generate US$15.5 trillion in net economic benefits.

“Managing these resources sustainably requires first that we understand deep-sea ecosystems and their role on the planet”

But to make all this happen, the nations of the world would have to co-operate to manage fishing and seafood farming in sustainable ways; and they would have to take steps to mitigate climate change.

The world would have to invest in a variety of ways of generating renewable energy. It would have to clean up the shipping business − 90% of global goods move across the sea’s surface − to reduce emissions and pollution.

And it would have to halt the decline of, and restore, salt marshes, seagrass beds and mangroves: these cover areas more than 50 times smaller than the world’s forests, but they can store carbon at 10 times the rate of land-based ecosystems.

The world would also have to seriously protect great tracts of the seas: at least 30%. Right now, only 2.6% is fully protected from fishing and other disturbance. The researchers argue that political action to deliver a healthy ocean has been lacking − until now. But, they add, “Our knowledge of the ocean is deep.”

Ten-year study

It may not be deep enough, though, which explains the emphasis on more ocean research. Right on cue, another team of scientists reminds the world that the deepest parts of the ocean cover 60% of the globe and most of this has yet to be properly explored.

So, 150 years after the history-making British research ship HMS Challenger began its first systematic measurement of the deep sea, a consortium of scientists from 45 laboratories and universities in 17 countries has called for a dedicated decade of systematic and detailed study of a saltwater habitat that begins at 200 metres and extends as far in a few places as 11,000 metres in depth.

This initiative, they argue in the journal Nature Ecology and Evolution, should happen during the United Nations Decade of Ocean Science for Sustainable Development, from 2021 to 2030.

“The deep seas and seabed are increasingly being used by society, and they are seen as a potential future asset for the resources they possess,” said Kerry Howell, an ecologist at the University of Plymouth in the UK, lead author. “But managing these resources sustainably requires first that we understand deep-sea ecosystems, and their role on the planet, its people and its atmosphere.” − Climate News Network

A decade of ocean research is about to begin to try to save the planet’s richest habitat from human destruction.

LONDON, 9 December, 2020 − Humans need urgently to invest in ocean research and protection. In return, the ocean could repay them handsomely, by soaking up atmospheric carbon, delivering huge amounts of renewable energy, providing six times more sustainable seafood, creating millions of jobs and generating trillions in economic benefits.

The oceans cover 70% of the planet but, a trio of scientists warn in the journal Nature, “for much too long, the ocean has been out of sight, out of mind and out of luck.”

From the margins of the coast to the deepest seas, the oceans’ habitats and the living creatures in them have been threatened by excessive and destructive fishing, they say.

“Unsustainable development along coastlines is destroying coral reefs, seagrass beds, salt marshes and mangrove forests. These house biodiversity, sequester carbon, provide nurseries for fish and buffer coasts against storm surges.

Separate approaches inadequate

Plastics and nutrients washed from the land are also killing wildlife. All of these threats erode the capacity of the ocean to provide nutritious food, jobs, medicines and pharmaceuticals as well as regulate the climate.”

But something can be done. A new report − commissioned by Norway, Palau, 12 other nations and a UN envoy, collectively responsible for two-fifths of the world’s coastlines, almost a third of the exclusive economic zones and a fifth of the world’s shipping − argues that it is not enough for individual nations to manage their sectors or confront challenging issues separately. The largest and deepest continuous living space on the planet demands something more.

The report finds that − if the world co-operated in an holistic approach to care for the oceans, and protected at least 30% of them − then by 2050 the deep blue sea could account for 20% of the carbon emission reductions needed to match the Paris climate agreement target of no more than 1.5°C warming above pre-industrial levels.

Such an initiative could exploit the ocean to provide 40 times the renewable energy generated worldwide in 2018. It could provide six times the sustainable seafood, create 12 million jobs and generate US$15.5 trillion in net economic benefits.

“Managing these resources sustainably requires first that we understand deep-sea ecosystems and their role on the planet”

But to make all this happen, the nations of the world would have to co-operate to manage fishing and seafood farming in sustainable ways; and they would have to take steps to mitigate climate change.

The world would have to invest in a variety of ways of generating renewable energy. It would have to clean up the shipping business − 90% of global goods move across the sea’s surface − to reduce emissions and pollution.

And it would have to halt the decline of, and restore, salt marshes, seagrass beds and mangroves: these cover areas more than 50 times smaller than the world’s forests, but they can store carbon at 10 times the rate of land-based ecosystems.

The world would also have to seriously protect great tracts of the seas: at least 30%. Right now, only 2.6% is fully protected from fishing and other disturbance. The researchers argue that political action to deliver a healthy ocean has been lacking − until now. But, they add, “Our knowledge of the ocean is deep.”

Ten-year study

It may not be deep enough, though, which explains the emphasis on more ocean research. Right on cue, another team of scientists reminds the world that the deepest parts of the ocean cover 60% of the globe and most of this has yet to be properly explored.

So, 150 years after the history-making British research ship HMS Challenger began its first systematic measurement of the deep sea, a consortium of scientists from 45 laboratories and universities in 17 countries has called for a dedicated decade of systematic and detailed study of a saltwater habitat that begins at 200 metres and extends as far in a few places as 11,000 metres in depth.

This initiative, they argue in the journal Nature Ecology and Evolution, should happen during the United Nations Decade of Ocean Science for Sustainable Development, from 2021 to 2030.

“The deep seas and seabed are increasingly being used by society, and they are seen as a potential future asset for the resources they possess,” said Kerry Howell, an ecologist at the University of Plymouth in the UK, lead author. “But managing these resources sustainably requires first that we understand deep-sea ecosystems, and their role on the planet, its people and its atmosphere.” − Climate News Network

Rising ocean heat leaves fish gasping for oxygen

Lack of oxygen will leave some fish gasping as the thermometer rises. Deep time offers a guide to those at greatest risk.

LONDON, 2 December, 2020 − As global temperatures soar, the planetary menu could start to dwindle. Cod, sea bass and haddock will move to cooler and more distant waters. Tropical species relying on the shelter of coral reefs could simply disappear. Fish gasping for oxygen will struggle to survive.

And although the world’s marine catch is already under pressure from pollution, ocean acidification and overfishing, the real threat is now clear. As ocean temperatures rise, oxygen levels in the world’s seas will fall, and the most active fish could start to stifle.

Some sea creatures will survive: sharks, rays and other cartilaginous fish will do better than the bony ones. Bivalves that cling to rocks will also cling on to life.

But some types of fish could be pushed to their tolerance limits, says a new study in the journal Global Change Biology, and global heating driven by ever-higher carbon dioxide levels in the atmosphere will be the primary cause.

“Warm water contains less oxygen than cool water. This tends to affect organisms that consume the most oxygen, which can mean that actively mobile animals are particularly affected,” said Carl Reddin of the Museum of Natural History in Berlin, who headed the research.

Heading for 3°C

He and his colleagues set themselves a simple challenge: why do some groups of marine creatures go extinct more often than others? The steady decline in fish catches on traditional grounds already has one obvious explanation: humans have overfished, and polluted. So the scientists decided to take a long cool look at the past.

“The deep time fossil record, conversely, is free from human impacts, and documents extinctions during ancient episodes of rapid climate warming, or hyperthermals,” they write.

They looked back across the evidence preserved in the rocks over the last 300 million years and identified what they call “six global hyperthermal events that shared a rapid increase in tropical sea surface temperatures, generally greater than 2°C, with an onset duration less than 100,000 years.”

In effect, they were looking for global conditions that matched those now happening. In the last 100 years, planetary average temperatures have risen by 1°C, and although almost all the world’s nations met in 2015 and vowed to try to contain global heating by 2100 to “well below” 2°C, the planet is heading towards a rise of more than 3°C above the long-term average in the next eight decades.

The Berlin team found that those groups of marine animals that − on the evidence of the fossil record − were most vulnerable to global warming in the deep past looked very like those that seem most in trouble today, among them the bony fishes.

“The deep time fossil record documents extinctions during ancient episodes of rapid climate warming”

The idea is not new. Other marine biologists have repeatedly warned of oxygen depletion in and beyond the fishing grounds.

Separately, there has been evidence that higher temperatures have begun to change the nature of the oceans, and fishermen have begun to count the cost as their catch migrates to waters that are cooler.

What this latest study does is clear up the uncertainty. Overfishing remains a problem. Ocean acidification will certainly affect some shellfish and possibly also fish behaviour. Pollution has already increased the number of marine dead zones.

But beyond that, the problem is simply one of temperature, and the latest study identifies those groups or classes of marine creature most at risk from another rise in the planetary thermometer: those sensitive to “warming-induced seawater de-oxygenation,” the researchers report.

And they add: “In anticipation of modern warming-driven marine extinctions, the trends illustrated in the fossil record offer an expedient preview.” − Climate News Network

Lack of oxygen will leave some fish gasping as the thermometer rises. Deep time offers a guide to those at greatest risk.

LONDON, 2 December, 2020 − As global temperatures soar, the planetary menu could start to dwindle. Cod, sea bass and haddock will move to cooler and more distant waters. Tropical species relying on the shelter of coral reefs could simply disappear. Fish gasping for oxygen will struggle to survive.

And although the world’s marine catch is already under pressure from pollution, ocean acidification and overfishing, the real threat is now clear. As ocean temperatures rise, oxygen levels in the world’s seas will fall, and the most active fish could start to stifle.

Some sea creatures will survive: sharks, rays and other cartilaginous fish will do better than the bony ones. Bivalves that cling to rocks will also cling on to life.

But some types of fish could be pushed to their tolerance limits, says a new study in the journal Global Change Biology, and global heating driven by ever-higher carbon dioxide levels in the atmosphere will be the primary cause.

“Warm water contains less oxygen than cool water. This tends to affect organisms that consume the most oxygen, which can mean that actively mobile animals are particularly affected,” said Carl Reddin of the Museum of Natural History in Berlin, who headed the research.

Heading for 3°C

He and his colleagues set themselves a simple challenge: why do some groups of marine creatures go extinct more often than others? The steady decline in fish catches on traditional grounds already has one obvious explanation: humans have overfished, and polluted. So the scientists decided to take a long cool look at the past.

“The deep time fossil record, conversely, is free from human impacts, and documents extinctions during ancient episodes of rapid climate warming, or hyperthermals,” they write.

They looked back across the evidence preserved in the rocks over the last 300 million years and identified what they call “six global hyperthermal events that shared a rapid increase in tropical sea surface temperatures, generally greater than 2°C, with an onset duration less than 100,000 years.”

In effect, they were looking for global conditions that matched those now happening. In the last 100 years, planetary average temperatures have risen by 1°C, and although almost all the world’s nations met in 2015 and vowed to try to contain global heating by 2100 to “well below” 2°C, the planet is heading towards a rise of more than 3°C above the long-term average in the next eight decades.

The Berlin team found that those groups of marine animals that − on the evidence of the fossil record − were most vulnerable to global warming in the deep past looked very like those that seem most in trouble today, among them the bony fishes.

“The deep time fossil record documents extinctions during ancient episodes of rapid climate warming”

The idea is not new. Other marine biologists have repeatedly warned of oxygen depletion in and beyond the fishing grounds.

Separately, there has been evidence that higher temperatures have begun to change the nature of the oceans, and fishermen have begun to count the cost as their catch migrates to waters that are cooler.

What this latest study does is clear up the uncertainty. Overfishing remains a problem. Ocean acidification will certainly affect some shellfish and possibly also fish behaviour. Pollution has already increased the number of marine dead zones.

But beyond that, the problem is simply one of temperature, and the latest study identifies those groups or classes of marine creature most at risk from another rise in the planetary thermometer: those sensitive to “warming-induced seawater de-oxygenation,” the researchers report.

And they add: “In anticipation of modern warming-driven marine extinctions, the trends illustrated in the fossil record offer an expedient preview.” − Climate News Network