Tag Archives: Oceans

Warming oceans deter more fish from spawning

When the moment to mate arrives, fish like to play it cool. So warming oceans create special problems for the generation game.

LONDON, 9 July, 2020 – German scientists now know why so many fish are so vulnerable to ever-warming oceans. Global heating imposes a harsh cost at the most critical time of all: the moment of spawning.

“Our findings show that, both as embryos in eggs and as adults ready to mate, fish are far more sensitive to heat than in their larval stage or as sexually mature adults outside the mating season,” said Flemming Dahlke, a marine biologist with the Alfred Wegener Institute at Bremerhaven.

“On the global average, for example, adults outside the mating season can survive in water that’s up to 10°C warmer than adults ready to mate, or fish eggs, can.”

The finding – if it is confirmed by other research – should clear up some of the puzzles associated with fish numbers. There is clear evidence, established repeatedly over the decades, that fish are responding to climate change.

But almost three fourths of the planet is blue ocean, and at depth is responding far more slowly than the land surface to global heating fuelled by fossil fuel exploitation that releases greenhouse gases.

Nearing the brink

Since fish in the temperate zones already experience a wide variation in seasonal water temperatures, it hasn’t been obvious why species such as cod have shifted nearer the Arctic, and sardines have migrated to the North Sea.

But marine creatures are on the move, and although there are other factors at work, including overfishing and the increasingly alarming changes in ocean chemistry, thanks to ever-higher levels of dissolved carbon dioxide, temperature change is part of the problem.

The latest answer, Dr Dahlke and his colleagues report in the journal Science, is that many fish may already be living near the limits of their thermal tolerance.

The temperature safety margins during the moments of spawning and embryo might be very precise, and over hundreds of thousands of years of evolution, marine and freshwater species have worked out just what is best for the next generation. Rapid global warming upsets this equilibrium.

“Adults outside the mating season can survive in water that’s up to 10°C warmer than adults ready to mate, or fish eggs, can”

The Bremerhaven scientists looked at experiments, observations and recorded data for the life cycles of 694 marine and freshwater species, to decide that oxygen supply is the key decider of reproductive success. Warmer waters carry less dissolved oxygen. Embryo fish have no gills: they cannot simply take in deeper breaths.

Fish about to mate are busy producing extra mass in the form of sperm and egg cells: this additional body mass also needs oxygen. Even at lower temperatures, piscine cardiovascular systems are under stress.

So the reasoning follows that, if global heating continues, climate change and rising water temperatures are likely to affect the reproduction of perhaps 60% of all fish species.

“Some species might successfully manage this change,” Dr Dahlke said.
“But if you consider the fact that fish have adapted their mating patterns to specific habitats over extremely long timeframes, and have tailored their mating cycles of specific ocean currents and food sources, it has to be assumed that being forced to abandon their normal spawning areas will mean major problems for them.” – Climate News Network

When the moment to mate arrives, fish like to play it cool. So warming oceans create special problems for the generation game.

LONDON, 9 July, 2020 – German scientists now know why so many fish are so vulnerable to ever-warming oceans. Global heating imposes a harsh cost at the most critical time of all: the moment of spawning.

“Our findings show that, both as embryos in eggs and as adults ready to mate, fish are far more sensitive to heat than in their larval stage or as sexually mature adults outside the mating season,” said Flemming Dahlke, a marine biologist with the Alfred Wegener Institute at Bremerhaven.

“On the global average, for example, adults outside the mating season can survive in water that’s up to 10°C warmer than adults ready to mate, or fish eggs, can.”

The finding – if it is confirmed by other research – should clear up some of the puzzles associated with fish numbers. There is clear evidence, established repeatedly over the decades, that fish are responding to climate change.

But almost three fourths of the planet is blue ocean, and at depth is responding far more slowly than the land surface to global heating fuelled by fossil fuel exploitation that releases greenhouse gases.

Nearing the brink

Since fish in the temperate zones already experience a wide variation in seasonal water temperatures, it hasn’t been obvious why species such as cod have shifted nearer the Arctic, and sardines have migrated to the North Sea.

But marine creatures are on the move, and although there are other factors at work, including overfishing and the increasingly alarming changes in ocean chemistry, thanks to ever-higher levels of dissolved carbon dioxide, temperature change is part of the problem.

The latest answer, Dr Dahlke and his colleagues report in the journal Science, is that many fish may already be living near the limits of their thermal tolerance.

The temperature safety margins during the moments of spawning and embryo might be very precise, and over hundreds of thousands of years of evolution, marine and freshwater species have worked out just what is best for the next generation. Rapid global warming upsets this equilibrium.

“Adults outside the mating season can survive in water that’s up to 10°C warmer than adults ready to mate, or fish eggs, can”

The Bremerhaven scientists looked at experiments, observations and recorded data for the life cycles of 694 marine and freshwater species, to decide that oxygen supply is the key decider of reproductive success. Warmer waters carry less dissolved oxygen. Embryo fish have no gills: they cannot simply take in deeper breaths.

Fish about to mate are busy producing extra mass in the form of sperm and egg cells: this additional body mass also needs oxygen. Even at lower temperatures, piscine cardiovascular systems are under stress.

So the reasoning follows that, if global heating continues, climate change and rising water temperatures are likely to affect the reproduction of perhaps 60% of all fish species.

“Some species might successfully manage this change,” Dr Dahlke said.
“But if you consider the fact that fish have adapted their mating patterns to specific habitats over extremely long timeframes, and have tailored their mating cycles of specific ocean currents and food sources, it has to be assumed that being forced to abandon their normal spawning areas will mean major problems for them.” – Climate News Network

Ocean sensitivity may lower carbon emissions cuts

Ocean sensitivity to atmospheric change is well established. But just how sensitive the oceans are remains a surprise to science.

LONDON, 30 June, 2020 – As greenhouse gas emissions soar, ocean sensitivity has quietly helped humanity to slow global heating: the seas have responded by absorbing more and more carbon dioxide from the atmosphere.

But should humans come to grips with the challenge of looming climate catastrophe and start to reduce emissions, the oceans could respond again – by absorbing less and slightly slowing the fall of the mercury in the global thermometer.

And there is even an immediate chance to test this proposal: if so, then oceans that have been each year absorbing more and more carbon from the atmosphere as greenhouse gas ratios rise will go into brief reverse, because of the global economic shutdown and fall in emissions triggered by the global pandemic of Covid-19.

For the first time in decades, the oceans could take up less carbon dioxide in 2020, according to a new study by US scientists in the American Geophysical Union journal AGU Advances.

“We didn’t realise until we did this work that these external forcings, like changes in the growth of atmospheric carbon dioxide, dominate the variability in the global ocean on year-to-year timescales. That’s a real surprise,” said Galen McKinley, of Columbia University’s Lamont-Doherty Earth Observatory.

Feedback in action

“As we reduce our emissions and the growth rate of atmospheric carbon dioxide slows down, it’s important to realise that the ocean carbon sink will respond by slowing down.”

The research should not be interpreted as an invitation to go on burning fossil fuels. It is another lesson in the intricacy of the traffic between atmosphere, rocks, oceans, and living things in an evolving world. And it is more immediately an exquisite example of what engineers call feedback.

In cases of negative feedback, the agency of change also triggers a way of slowing that change. Since 1750 – the birth of the Industrial Revolution – human economies have added 440 billion tonnes of carbon to the planetary atmosphere.

For most of human history carbon dioxide ratios in the atmosphere had hovered around 285 parts per million. They have now gone beyond 400 ppm, and global average temperatures have already risen by more than 1°C.

They’d be even higher but for the oceans, which have responded by absorbing around 39% of all that extra carbon from coal, oil and gas combustion. So the oceans are sensitive to atmospheric change, and respond.

“There will be a time when the ocean will limit the effectiveness of mitigation actions, and this should be accounted for in policymaking”

The latest study is a lesson in how sensitive: Professor McKinley and her colleagues used computer models to try to understand better why the ocean uptake of carbon varies.

In the early 1990s, the ocean absorption of carbon dioxide varied: dramatically at first, because a devastating volcanic eruption of Mt Pinatubo in the Philippines in 1991 that darkened the stratosphere also accelerated ocean uptake.

And then the ocean uptake started to slow, as the skies cleared but also as the collapse of the Soviet Union and its satellite nations changed the global pattern of fuel use. It went on declining until 2001, when fossil fuel use started to accelerate. And then the ocean sink started once again to become more absorbent.

Such research is a reminder of how much scientists still don’t know about the machinery of the planet. That greenhouse gas from fossil fuel combustion drives global heating is not now in doubt. But the precise speed, and the drivers and brakes of positive and negative feedback, remain less certain.

Many feedbacks are positive: as the Arctic warms, carbon plant remains frozen in the permafrost will start to decay, release more methane and carbon dioxide, and accelerate warming.

Forest concern

As the sea ice retreats, and the ice reflects less sunlight, the exposed blue seas will absorb ever more radiation, to turn up the planetary temperatures. A warner world will be a wetter one, which may also mean a rise in the rate of warming.

But the ocean is not the only example of negative feedback. More carbon dioxide seems to mean more vigorous plant growth, and there is clear evidence that the world’s great forests are an important carbon sink: an example of negative feedback. That is why almost all governments recognise the importance of forest conservation.

Action however is uneven, forests are still being degraded, and there is alarming evidence that at some point, as temperatures get too high, the tropical forests could start surrendering the carbon they have for millennia absorbed, and become agents of positive feedback.

Professor McKinley warns that – as global emissions are cut – there will be a phase during which ocean uptake slows. If so, then planetary temperature rise will not slow as fast as hoped: extra carbon dioxide will linger, to contribute to warming.

“We need to discuss this coming feedback. We want people to understand that there will be a time when the ocean will limit the effectiveness of mitigation actions, and this should also be accounted for in policymaking.” – Climate News Network

Ocean sensitivity to atmospheric change is well established. But just how sensitive the oceans are remains a surprise to science.

LONDON, 30 June, 2020 – As greenhouse gas emissions soar, ocean sensitivity has quietly helped humanity to slow global heating: the seas have responded by absorbing more and more carbon dioxide from the atmosphere.

But should humans come to grips with the challenge of looming climate catastrophe and start to reduce emissions, the oceans could respond again – by absorbing less and slightly slowing the fall of the mercury in the global thermometer.

And there is even an immediate chance to test this proposal: if so, then oceans that have been each year absorbing more and more carbon from the atmosphere as greenhouse gas ratios rise will go into brief reverse, because of the global economic shutdown and fall in emissions triggered by the global pandemic of Covid-19.

For the first time in decades, the oceans could take up less carbon dioxide in 2020, according to a new study by US scientists in the American Geophysical Union journal AGU Advances.

“We didn’t realise until we did this work that these external forcings, like changes in the growth of atmospheric carbon dioxide, dominate the variability in the global ocean on year-to-year timescales. That’s a real surprise,” said Galen McKinley, of Columbia University’s Lamont-Doherty Earth Observatory.

Feedback in action

“As we reduce our emissions and the growth rate of atmospheric carbon dioxide slows down, it’s important to realise that the ocean carbon sink will respond by slowing down.”

The research should not be interpreted as an invitation to go on burning fossil fuels. It is another lesson in the intricacy of the traffic between atmosphere, rocks, oceans, and living things in an evolving world. And it is more immediately an exquisite example of what engineers call feedback.

In cases of negative feedback, the agency of change also triggers a way of slowing that change. Since 1750 – the birth of the Industrial Revolution – human economies have added 440 billion tonnes of carbon to the planetary atmosphere.

For most of human history carbon dioxide ratios in the atmosphere had hovered around 285 parts per million. They have now gone beyond 400 ppm, and global average temperatures have already risen by more than 1°C.

They’d be even higher but for the oceans, which have responded by absorbing around 39% of all that extra carbon from coal, oil and gas combustion. So the oceans are sensitive to atmospheric change, and respond.

“There will be a time when the ocean will limit the effectiveness of mitigation actions, and this should be accounted for in policymaking”

The latest study is a lesson in how sensitive: Professor McKinley and her colleagues used computer models to try to understand better why the ocean uptake of carbon varies.

In the early 1990s, the ocean absorption of carbon dioxide varied: dramatically at first, because a devastating volcanic eruption of Mt Pinatubo in the Philippines in 1991 that darkened the stratosphere also accelerated ocean uptake.

And then the ocean uptake started to slow, as the skies cleared but also as the collapse of the Soviet Union and its satellite nations changed the global pattern of fuel use. It went on declining until 2001, when fossil fuel use started to accelerate. And then the ocean sink started once again to become more absorbent.

Such research is a reminder of how much scientists still don’t know about the machinery of the planet. That greenhouse gas from fossil fuel combustion drives global heating is not now in doubt. But the precise speed, and the drivers and brakes of positive and negative feedback, remain less certain.

Many feedbacks are positive: as the Arctic warms, carbon plant remains frozen in the permafrost will start to decay, release more methane and carbon dioxide, and accelerate warming.

Forest concern

As the sea ice retreats, and the ice reflects less sunlight, the exposed blue seas will absorb ever more radiation, to turn up the planetary temperatures. A warner world will be a wetter one, which may also mean a rise in the rate of warming.

But the ocean is not the only example of negative feedback. More carbon dioxide seems to mean more vigorous plant growth, and there is clear evidence that the world’s great forests are an important carbon sink: an example of negative feedback. That is why almost all governments recognise the importance of forest conservation.

Action however is uneven, forests are still being degraded, and there is alarming evidence that at some point, as temperatures get too high, the tropical forests could start surrendering the carbon they have for millennia absorbed, and become agents of positive feedback.

Professor McKinley warns that – as global emissions are cut – there will be a phase during which ocean uptake slows. If so, then planetary temperature rise will not slow as fast as hoped: extra carbon dioxide will linger, to contribute to warming.

“We need to discuss this coming feedback. We want people to understand that there will be a time when the ocean will limit the effectiveness of mitigation actions, and this should also be accounted for in policymaking.” – Climate News Network

Clean ships needed now to cut polluting emissions

The vessels plying the world’s oceans release huge volumes of polluting emissions. Existing fleets badly need a clean-up.

LONDON, 25 June, 2020 − The shipping industry is in urgent need of a makeover: while limited attempts are being made to lessen polluting emissions of climate-changing greenhouse gases in the road transport and aviation sectors, shipping lags even further behind in the clean-up stakes.

Maritime traffic is a major source of emissions, each year belching out thousands of tonnes of greenhouse gases (GHGs) and other pollutants. “If the sector were a country, it would be the 6th highest emitter [of GHGs] in the world, ranked between Germany and Japan”, says a study in the journal BMC Energy.

Involving researchers at the Tyndall Centre and the University of Manchester in the UK, the study says reducing emissions in the shipping industry has tended to focus on the introduction of new, low-carbon vessels.

The researchers point out that ships have a comparatively long life span: in 2018 the average age of a ship being scrapped was 28 years.

The study says ageing ships are a major source of pollution: in order to cut global emissions of CO2 and other gases and meet the targets set in the 2015 Paris Agreement on climate change, the world’s existing shipping fleet must undergo a substantial revamp.

“There must be much greater attention paid to retrofitting the existing fleet, before it’s too late to deliver on the net-zero target”

The shipping industry cannot wait for the arrival of new, low-carbon ships, says the study.

“Policies to cut shipping CO2 must focus attention on decarbonising and retrofitting existing ships, rather than rely on new, more efficient ships to achieve the necessary carbon reductions”, it says.

Shipping is the lifeline of world trade: tens of thousands of vessels crisscross the oceans each year, carrying between 80% and 90% of global goods traffic. At any one time about 90,000 vessels are at sea.

Most vessels – both trade and cruise ships − burn low-grade, polluting forms of fuel. These emit not only GHGs but large amounts of sulphur dioxide, nitrogen oxides and particulates which are seriously damaging to health.

A 2018 report in the journal Nature Communications estimated that sulphur-rich shipping emissions account for up to a quarter of a million deaths and more than six million cases of childhood asthma around the world each year.

Sluggish action

The International Maritime Organization has set various climate change targets, including a reduction of at least 50% in GHG emissions by 2050, compared with levels in 2008.

There’s been little action so far. A report by Transport and Environment, a Brussels-based non-governmental organisation, says shipping emissions – in both the transport and cruise ship sectors – have been largely unregulated and subject to very few financial penalties.

A review of the shipping sector by the analysis groups the New Climate Institute and Climate Analytics says the industry is nowhere near reaching its targets and, on present projections, shipping emissions will continue rising.

“There is tremendous potential for the international shipping industry to decarbonise completely and reach zero emissions by 2050, yet there is very little sign of this sector moving anywhere near fast enough and certainly nowhere near a Paris Agreement pathway”, says Climate Analytics.

The University of Manchester/Tyndall Centre study highlights some of the ways ships can cut emissions, such as travelling at slower speeds to reduce fuel consumption, connecting to the local grid for electricity while in port, and retrofitting other energy-saving measures such as Flettner rotors to help propulsion.

Delay unaffordable

“This research highlights the key role existing ships play in tackling the climate crisis”, says James Mason, a researcher at the Tyndall Centre.

“We must push for quick action for these ships, whether through speed reductions or other innovative solutions such as wind propulsion.”

Dr John Broderick, a climate change specialist at the University of Manchester, says time is of the essence.

“Unlike in aviation, there are many different ways to decarbonise the shipping sector, but there must be much greater attention paid to retrofitting the existing fleet, before it’s too late to deliver on the net-zero target.”

Shipping industry analysts say bringing about wholesale change in the sector is a formidable task. The industry is extremely diffuse, involving multiple countries, ship owners and transport companies, while overall governance is weak. − Climate News Network

The vessels plying the world’s oceans release huge volumes of polluting emissions. Existing fleets badly need a clean-up.

LONDON, 25 June, 2020 − The shipping industry is in urgent need of a makeover: while limited attempts are being made to lessen polluting emissions of climate-changing greenhouse gases in the road transport and aviation sectors, shipping lags even further behind in the clean-up stakes.

Maritime traffic is a major source of emissions, each year belching out thousands of tonnes of greenhouse gases (GHGs) and other pollutants. “If the sector were a country, it would be the 6th highest emitter [of GHGs] in the world, ranked between Germany and Japan”, says a study in the journal BMC Energy.

Involving researchers at the Tyndall Centre and the University of Manchester in the UK, the study says reducing emissions in the shipping industry has tended to focus on the introduction of new, low-carbon vessels.

The researchers point out that ships have a comparatively long life span: in 2018 the average age of a ship being scrapped was 28 years.

The study says ageing ships are a major source of pollution: in order to cut global emissions of CO2 and other gases and meet the targets set in the 2015 Paris Agreement on climate change, the world’s existing shipping fleet must undergo a substantial revamp.

“There must be much greater attention paid to retrofitting the existing fleet, before it’s too late to deliver on the net-zero target”

The shipping industry cannot wait for the arrival of new, low-carbon ships, says the study.

“Policies to cut shipping CO2 must focus attention on decarbonising and retrofitting existing ships, rather than rely on new, more efficient ships to achieve the necessary carbon reductions”, it says.

Shipping is the lifeline of world trade: tens of thousands of vessels crisscross the oceans each year, carrying between 80% and 90% of global goods traffic. At any one time about 90,000 vessels are at sea.

Most vessels – both trade and cruise ships − burn low-grade, polluting forms of fuel. These emit not only GHGs but large amounts of sulphur dioxide, nitrogen oxides and particulates which are seriously damaging to health.

A 2018 report in the journal Nature Communications estimated that sulphur-rich shipping emissions account for up to a quarter of a million deaths and more than six million cases of childhood asthma around the world each year.

Sluggish action

The International Maritime Organization has set various climate change targets, including a reduction of at least 50% in GHG emissions by 2050, compared with levels in 2008.

There’s been little action so far. A report by Transport and Environment, a Brussels-based non-governmental organisation, says shipping emissions – in both the transport and cruise ship sectors – have been largely unregulated and subject to very few financial penalties.

A review of the shipping sector by the analysis groups the New Climate Institute and Climate Analytics says the industry is nowhere near reaching its targets and, on present projections, shipping emissions will continue rising.

“There is tremendous potential for the international shipping industry to decarbonise completely and reach zero emissions by 2050, yet there is very little sign of this sector moving anywhere near fast enough and certainly nowhere near a Paris Agreement pathway”, says Climate Analytics.

The University of Manchester/Tyndall Centre study highlights some of the ways ships can cut emissions, such as travelling at slower speeds to reduce fuel consumption, connecting to the local grid for electricity while in port, and retrofitting other energy-saving measures such as Flettner rotors to help propulsion.

Delay unaffordable

“This research highlights the key role existing ships play in tackling the climate crisis”, says James Mason, a researcher at the Tyndall Centre.

“We must push for quick action for these ships, whether through speed reductions or other innovative solutions such as wind propulsion.”

Dr John Broderick, a climate change specialist at the University of Manchester, says time is of the essence.

“Unlike in aviation, there are many different ways to decarbonise the shipping sector, but there must be much greater attention paid to retrofitting the existing fleet, before it’s too late to deliver on the net-zero target.”

Shipping industry analysts say bringing about wholesale change in the sector is a formidable task. The industry is extremely diffuse, involving multiple countries, ship owners and transport companies, while overall governance is weak. − Climate News Network

Antarctic melting could bring a much hotter future

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

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

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

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

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

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

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

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

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

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

Tell-tale line

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

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

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

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

Faster change ahead

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Tell-tale line

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

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

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

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

Faster change ahead

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

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

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

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

Threatened mangrove forests won’t protect coasts

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

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

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

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

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

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

Sheltering people

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

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

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

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

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

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

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

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

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

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

Not enough protection

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

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

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

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

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

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

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

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

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

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

Sheltering people

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

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

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

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

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

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

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

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

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

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

Not enough protection

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

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

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

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

Ocean warming spurs marine life to rapid migration

Far from the sunlight and even at the lowest temperatures, ocean warming is making marine life uncomfortable.

LONDON, 15 June, 2020 – Scientists have taken the temperature of the deep seas and found alarming signs of change: ocean warming is prompting many creatures to migrate fast.

The species that live in the deep and the dark are moving towards the poles at twice to almost four times the speed of surface creatures.

The implication is that – even though conditions in the abyssal plain are far more stable than surface currents – the creatures of the abyss are feeling the heat.

The oceans of the world cover almost three-fourths of the globe and, from surface to seafloor, provide at least 90% of the planet’s living space.

And although there has been repeated attention to the health of the waters that define the Blue Planet, it remains immensely difficult to arrive at a consistent, global figure for rates of change in temperature of the planet’s largest habitat.

“Marine life in the deep ocean will face escalating threats from ocean warming until the end of the century, no matter what we do now”

Oceanographers are fond of complaining that humankind knows more about the surface of Mars and Venus than it does about the bedrock and marine sediments at depth.

This may still be true, but repeated studies have confirmed that the ocean floor ecosystem is surprisingly rich, varied and potentially at risk.

Now researchers from Australia, Europe, Japan, South Africa and the Philippines report in the journal Nature Climate Change that although they could not deliver thermometer readings, they had found an indirect measure: the rate at which marine creatures move on because they don’t care for their local temperature shifts.

They call this “climate velocity”. They had data for 20,000 marine species. And they found that overall, at depths greater than 1000 metres, marine creatures have been on the move much faster than their fellow citizens near the surface, over the second half of the 20th century.

Computer simulations tell an even more alarming story: by the end of this century, creatures in the mesopelagic layer – from 200 metres down to 1000 metres – will be moving away between four and 11 times faster than those at the surface do now.

Faster migrants

The finding is indirectly supported by a second and unrelated study on the same day in the journal Nature Ecology & Evolution. French scientists looked at studies of more than 12,000 kinds of the migrations of bacteria, plant, fungus and animal to find that sea creatures are already floating, swimming or crawling towards the poles six times faster than those on land, as a response to global heating driven by profligate human use of fossil fuels.

So shifts in range can be interpreted as an indicator of the stress on the ocean habitats. This creates complications for conservationists arguing for internationally protected zones – protected from fishing trawl nets, and from submarine mining operations – because, if for no other reason, not only are ocean creatures moving at different speeds at different depths; some of the shifts are in different directions.

“Significantly reducing carbon emissions is vital to control warming and help take control of climate velocities in the surface layers of the ocean by 2100”, said Anthony Richardson of the University of Queensland in Australia, one of the authors.

“But because of the immense size and depth of the ocean, warming already observed at the ocean surface will mix into deeper waters. This means that marine life in the deep ocean will face escalating threats from ocean warming until the end of the century, no matter what we do now.

“This leaves only one option – act urgently to alleviate other human-generated threats to deep sea life, including seabed mining and deep-sea bottom-fishing.” – Climate News Network

Far from the sunlight and even at the lowest temperatures, ocean warming is making marine life uncomfortable.

LONDON, 15 June, 2020 – Scientists have taken the temperature of the deep seas and found alarming signs of change: ocean warming is prompting many creatures to migrate fast.

The species that live in the deep and the dark are moving towards the poles at twice to almost four times the speed of surface creatures.

The implication is that – even though conditions in the abyssal plain are far more stable than surface currents – the creatures of the abyss are feeling the heat.

The oceans of the world cover almost three-fourths of the globe and, from surface to seafloor, provide at least 90% of the planet’s living space.

And although there has been repeated attention to the health of the waters that define the Blue Planet, it remains immensely difficult to arrive at a consistent, global figure for rates of change in temperature of the planet’s largest habitat.

“Marine life in the deep ocean will face escalating threats from ocean warming until the end of the century, no matter what we do now”

Oceanographers are fond of complaining that humankind knows more about the surface of Mars and Venus than it does about the bedrock and marine sediments at depth.

This may still be true, but repeated studies have confirmed that the ocean floor ecosystem is surprisingly rich, varied and potentially at risk.

Now researchers from Australia, Europe, Japan, South Africa and the Philippines report in the journal Nature Climate Change that although they could not deliver thermometer readings, they had found an indirect measure: the rate at which marine creatures move on because they don’t care for their local temperature shifts.

They call this “climate velocity”. They had data for 20,000 marine species. And they found that overall, at depths greater than 1000 metres, marine creatures have been on the move much faster than their fellow citizens near the surface, over the second half of the 20th century.

Computer simulations tell an even more alarming story: by the end of this century, creatures in the mesopelagic layer – from 200 metres down to 1000 metres – will be moving away between four and 11 times faster than those at the surface do now.

Faster migrants

The finding is indirectly supported by a second and unrelated study on the same day in the journal Nature Ecology & Evolution. French scientists looked at studies of more than 12,000 kinds of the migrations of bacteria, plant, fungus and animal to find that sea creatures are already floating, swimming or crawling towards the poles six times faster than those on land, as a response to global heating driven by profligate human use of fossil fuels.

So shifts in range can be interpreted as an indicator of the stress on the ocean habitats. This creates complications for conservationists arguing for internationally protected zones – protected from fishing trawl nets, and from submarine mining operations – because, if for no other reason, not only are ocean creatures moving at different speeds at different depths; some of the shifts are in different directions.

“Significantly reducing carbon emissions is vital to control warming and help take control of climate velocities in the surface layers of the ocean by 2100”, said Anthony Richardson of the University of Queensland in Australia, one of the authors.

“But because of the immense size and depth of the ocean, warming already observed at the ocean surface will mix into deeper waters. This means that marine life in the deep ocean will face escalating threats from ocean warming until the end of the century, no matter what we do now.

“This leaves only one option – act urgently to alleviate other human-generated threats to deep sea life, including seabed mining and deep-sea bottom-fishing.” – Climate News Network

Human action will decide how much sea levels rise

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

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

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

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

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

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

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

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

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

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

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

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

Lessons from prehistory

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Lessons from prehistory

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

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

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

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

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

Plastic waste now litters Antarctic shore

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

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

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

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

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

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

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

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

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

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

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

Remedial efforts

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Remedial efforts

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

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

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

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

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

Sea level rise threatens UK nuclear reactor plans

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

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

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

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

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

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

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

Catastrophic accident risk

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

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

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

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

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

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

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

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

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

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

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

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

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

Fuel storage problem

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

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

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

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

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

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

Dungeness jeopardy

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

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

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

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

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

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

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

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

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

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

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

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

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

Catastrophic accident risk

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

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

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

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

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

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

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

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

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

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

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

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

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

Fuel storage problem

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

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

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

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

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

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

Dungeness jeopardy

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

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

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

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

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

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

North Pole may be clear water by mid-century

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

 

Within 30 years, there could be clear blue water over the North Pole – not good news for most of the planet.

LONDON, 25 April, 2020 – Within three decades, the North Pole could be free of sea ice in the late summer. The latest and most advanced climate simulations, tested by 21 research institutes from around the world, predict that if humans go on emitting ever-greater volumes of carbon dioxide from fossil fuel combustion and other actions, then before 2050, for the first time in human history, there could be no ice over the North Pole.

And a team of research scientists aboard a ship intent on spending a year observing the drift of sea ice across the Arctic Ocean has been warned that they may have to finish early: the ice supposed to hold the ship fast could melt too soon.

The loss of sea ice promises devastating consequences for the rich life in the most northern waters. The ice reflects sunlight back into space and keeps the Arctic cool. It also provides space for seals on which to haul out, and hunting grounds for blubber-hungry polar bears.

And although human inaction in the climate emergency makes the loss of polar ice ever more probable, so much greenhouse gas has already built up in the planetary atmosphere that it could happen anyway.

Taken aback

“If we reduce global emissions rapidly and substantially, and thus keep our warming below 2°C relative to pre-industrial levels, sea ice will nevertheless likely disappear occasionally in summer even before 2050,” said Dirk Notz, of the University of Hamburg in Germany, who led the study. “This really surprised us.”

Climate scientists first warned of the accelerating loss of Arctic sea ice two decades ago, and have repeatedly re-examined the climate predictions, each time with much the same outcome.

The loss of ice promises new trade routes between Atlantic and Pacific Oceans, but the cost of a warming Arctic could have catastrophic economic consequences.

The pattern of the northern hemisphere climate is driven by the temperature difference between the Arctic and the tropics, and rapid polar warming both disturbs temperate climate regimes and brings ever higher sea levels, with accelerating ice loss from Greenland, which right now bears enough ice to raise global sea levels by more than seven metres.

“The changes in the Arctic system are so incredibly rapid that even our satellite observations from 15 years ago are unlike the Arctic today”

Dr Notz and his co-authors report in the journal Geophysical Research Letters that they used the very latest climate model developed for the Intergovernmental Panel on Climate Change and tested it on a range of 40 possible climate outcomes.

In most simulations, the Arctic sea ice was reduced to less than a million square kilometres – polar researchers call this “practically sea-ice free” – in the month of September for the first time before 2050. Even if human fossil fuel use was sharply reduced, the ocean could be free of ice some years; if not, the pole could become open water most years.

And a second study, in the journal The Cryosphere, offers a measure of the sea ice loss even now. More than a century ago, the great explorer Fridtjof Nansen sailed his ship the Fram into the polar ice, became fast, and travelled with the floe across the Arctic Ocean.

His became the first scientific observation of a phenomenon called the trans-Polar drift, which takes algae, sediments and nutrients – and increasingly, plastic pollution – across the Arctic from Siberia to Canada and Greenland.

Melted out

In October a team of international researchers boarded a vessel called Polarstern with the intention of measuring the ice movement in the modern Arctic in more detail. They had planned for a year fast in the ice. Their project even has a name: Mosaic, or Multidisciplinary drifting Observatory for the Study of Arctic Climate.

But climate simulations by the US scientists reveal that in every sense, the project is on thin ice and could end prematurely. The flow of ice could be faster, and carry the ship further, than expected: nearly one in five of the simulations also predicted that the ship could melt out of the ice in less than a year.

“The changes in the Arctic system are so incredibly rapid that even our satellite observations from 15 years ago are unlike the Arctic today,” said one of the authors, Marika Holland of the US National Center for Atmospheric Research.

“Now there is thinner ice, which moves more quickly, and there is less snow cover. It is a totally different ice regime.” – Climate News Network

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

 

Within 30 years, there could be clear blue water over the North Pole – not good news for most of the planet.

LONDON, 25 April, 2020 – Within three decades, the North Pole could be free of sea ice in the late summer. The latest and most advanced climate simulations, tested by 21 research institutes from around the world, predict that if humans go on emitting ever-greater volumes of carbon dioxide from fossil fuel combustion and other actions, then before 2050, for the first time in human history, there could be no ice over the North Pole.

And a team of research scientists aboard a ship intent on spending a year observing the drift of sea ice across the Arctic Ocean has been warned that they may have to finish early: the ice supposed to hold the ship fast could melt too soon.

The loss of sea ice promises devastating consequences for the rich life in the most northern waters. The ice reflects sunlight back into space and keeps the Arctic cool. It also provides space for seals on which to haul out, and hunting grounds for blubber-hungry polar bears.

And although human inaction in the climate emergency makes the loss of polar ice ever more probable, so much greenhouse gas has already built up in the planetary atmosphere that it could happen anyway.

Taken aback

“If we reduce global emissions rapidly and substantially, and thus keep our warming below 2°C relative to pre-industrial levels, sea ice will nevertheless likely disappear occasionally in summer even before 2050,” said Dirk Notz, of the University of Hamburg in Germany, who led the study. “This really surprised us.”

Climate scientists first warned of the accelerating loss of Arctic sea ice two decades ago, and have repeatedly re-examined the climate predictions, each time with much the same outcome.

The loss of ice promises new trade routes between Atlantic and Pacific Oceans, but the cost of a warming Arctic could have catastrophic economic consequences.

The pattern of the northern hemisphere climate is driven by the temperature difference between the Arctic and the tropics, and rapid polar warming both disturbs temperate climate regimes and brings ever higher sea levels, with accelerating ice loss from Greenland, which right now bears enough ice to raise global sea levels by more than seven metres.

“The changes in the Arctic system are so incredibly rapid that even our satellite observations from 15 years ago are unlike the Arctic today”

Dr Notz and his co-authors report in the journal Geophysical Research Letters that they used the very latest climate model developed for the Intergovernmental Panel on Climate Change and tested it on a range of 40 possible climate outcomes.

In most simulations, the Arctic sea ice was reduced to less than a million square kilometres – polar researchers call this “practically sea-ice free” – in the month of September for the first time before 2050. Even if human fossil fuel use was sharply reduced, the ocean could be free of ice some years; if not, the pole could become open water most years.

And a second study, in the journal The Cryosphere, offers a measure of the sea ice loss even now. More than a century ago, the great explorer Fridtjof Nansen sailed his ship the Fram into the polar ice, became fast, and travelled with the floe across the Arctic Ocean.

His became the first scientific observation of a phenomenon called the trans-Polar drift, which takes algae, sediments and nutrients – and increasingly, plastic pollution – across the Arctic from Siberia to Canada and Greenland.

Melted out

In October a team of international researchers boarded a vessel called Polarstern with the intention of measuring the ice movement in the modern Arctic in more detail. They had planned for a year fast in the ice. Their project even has a name: Mosaic, or Multidisciplinary drifting Observatory for the Study of Arctic Climate.

But climate simulations by the US scientists reveal that in every sense, the project is on thin ice and could end prematurely. The flow of ice could be faster, and carry the ship further, than expected: nearly one in five of the simulations also predicted that the ship could melt out of the ice in less than a year.

“The changes in the Arctic system are so incredibly rapid that even our satellite observations from 15 years ago are unlike the Arctic today,” said one of the authors, Marika Holland of the US National Center for Atmospheric Research.

“Now there is thinner ice, which moves more quickly, and there is less snow cover. It is a totally different ice regime.” – Climate News Network