Category Archives: Oceans

Antarctic depths warm far beyond oceanic average

Heat from factories and car exhausts must go somewhere. A surprising amount is now sunk in the remote Antarctic depths.

LONDON, 28 October, 2020 − Thanks to global heating, a vital part of the Southern Ocean is warming at a rate five times faster than the average for the Blue Planet as a whole, in the far Antarctic depths: 2000 metres or more below the surface of the Weddell Sea.

It is happening because at that depth the Weddell Sea has absorbed five times as much atmospheric heat − fuelled by greenhouse gas emissions from human fossil fuel combustion − as the average for the rest of the ocean. But what happens out of sight and far below the surface may not stay invisible. The Weddell Sea is where vast volumes of water circulate.

The fear is that such dramatic warming at depth could end up weakening a powerful current that encircles Antarctica, according to a new study in the Journal of Climate.

The evidence comes from 30 years of temperature and salinity samples, taken at the same spot and through the entire water column, with exquisite accuracy, by scientists aboard the German research icebreaker Polarstern.

“Our time series confirms the pivotal role of the Southern Ocean and especially the Weddell Sea in terms of storing heat in the depths of the world’s oceans”

“Our data shows a clear division in the water column of the Weddell Sea. While the water in the upper 700 metres has hardly warmed at all, in the deeper regions we’re seeing a consistent temperature rise of 0.0021 to 0.0024 degrees Celsius per year,” said Volker Strass, of the Alfred Wegener Institute in Bremerhaven in Germany.

“Since the ocean has roughly 1,000 times the heat capacity of the atmosphere, these numbers represent an enormous scale of heat absorption. By using the temperature rise to calculate the warming rate in watts per square metre, you can see that over the past 30 years, at depths of over 2,000 metres, the Weddell Sea has absorbed five times as much heat as the rest of the ocean on average.”

The global ocean is the great absorber of atmospheric shock. The deep blue sea has so far absorbed more than nine-tenths of the heat trapped by greenhouse gas emissions in the atmosphere.

The Weddell Sea begins at the extreme south of the Atlantic Ocean: it is roughly 10 times the size of Europe’s North Sea. Here tremendous volumes of water cool down. As sea ice forms on the surface the remaining waters become more salty, and because they have become colder, and denser, sink to the bottom, to spread at depth to drive deep sea flow into the oceans.

Ocean circulation risk

This act of overturning − the sinking of surface waters for thousands of metres into the Antarctic depths − is part of the machinery of ocean circulation that drives and modifies the world’s weather systems, and the climate.

The problem is that if the bottom waters are warming − and are therefore less dense − then this could weaken or stall the mechanism for ocean circulation. In the past 30 years the prevailing winds have shifted and intensified, and the flow speed of ocean water has increased to deliver more heat to the Weddell Sea with each decade.

Warming ocean waters have already been implicated in the loss of sea ice  cover that normally slows the flow of Antarctica’s continental glaciers. And warming in the Arctic has already triggered worries about the future of the “Atlantic Conveyer,” that enormous circulation of water that distributes heat from the Equator to the Poles and keeps northern Europe much warmer than its latitudes would dictate.

“Our time series confirms the pivotal role of the Southern Ocean and especially the Weddell Sea in terms of storing heat in the depths of the world’s oceans,” said Dr Strass. − Climate News Network

Heat from factories and car exhausts must go somewhere. A surprising amount is now sunk in the remote Antarctic depths.

LONDON, 28 October, 2020 − Thanks to global heating, a vital part of the Southern Ocean is warming at a rate five times faster than the average for the Blue Planet as a whole, in the far Antarctic depths: 2000 metres or more below the surface of the Weddell Sea.

It is happening because at that depth the Weddell Sea has absorbed five times as much atmospheric heat − fuelled by greenhouse gas emissions from human fossil fuel combustion − as the average for the rest of the ocean. But what happens out of sight and far below the surface may not stay invisible. The Weddell Sea is where vast volumes of water circulate.

The fear is that such dramatic warming at depth could end up weakening a powerful current that encircles Antarctica, according to a new study in the Journal of Climate.

The evidence comes from 30 years of temperature and salinity samples, taken at the same spot and through the entire water column, with exquisite accuracy, by scientists aboard the German research icebreaker Polarstern.

“Our time series confirms the pivotal role of the Southern Ocean and especially the Weddell Sea in terms of storing heat in the depths of the world’s oceans”

“Our data shows a clear division in the water column of the Weddell Sea. While the water in the upper 700 metres has hardly warmed at all, in the deeper regions we’re seeing a consistent temperature rise of 0.0021 to 0.0024 degrees Celsius per year,” said Volker Strass, of the Alfred Wegener Institute in Bremerhaven in Germany.

“Since the ocean has roughly 1,000 times the heat capacity of the atmosphere, these numbers represent an enormous scale of heat absorption. By using the temperature rise to calculate the warming rate in watts per square metre, you can see that over the past 30 years, at depths of over 2,000 metres, the Weddell Sea has absorbed five times as much heat as the rest of the ocean on average.”

The global ocean is the great absorber of atmospheric shock. The deep blue sea has so far absorbed more than nine-tenths of the heat trapped by greenhouse gas emissions in the atmosphere.

The Weddell Sea begins at the extreme south of the Atlantic Ocean: it is roughly 10 times the size of Europe’s North Sea. Here tremendous volumes of water cool down. As sea ice forms on the surface the remaining waters become more salty, and because they have become colder, and denser, sink to the bottom, to spread at depth to drive deep sea flow into the oceans.

Ocean circulation risk

This act of overturning − the sinking of surface waters for thousands of metres into the Antarctic depths − is part of the machinery of ocean circulation that drives and modifies the world’s weather systems, and the climate.

The problem is that if the bottom waters are warming − and are therefore less dense − then this could weaken or stall the mechanism for ocean circulation. In the past 30 years the prevailing winds have shifted and intensified, and the flow speed of ocean water has increased to deliver more heat to the Weddell Sea with each decade.

Warming ocean waters have already been implicated in the loss of sea ice  cover that normally slows the flow of Antarctica’s continental glaciers. And warming in the Arctic has already triggered worries about the future of the “Atlantic Conveyer,” that enormous circulation of water that distributes heat from the Equator to the Poles and keeps northern Europe much warmer than its latitudes would dictate.

“Our time series confirms the pivotal role of the Southern Ocean and especially the Weddell Sea in terms of storing heat in the depths of the world’s oceans,” said Dr Strass. − Climate News Network

Hotter seas imperil both human and marine life

Climate warming brings hotter seas. The waters mix less. And conditions for some creatures could grow increasingly stifling.

LONDON, 9 October, 2020 − Climate change has led to hotter seas across the world: in 2018 European water temperatures reached record levels, and a marine heatwave in the north-east Pacific devastated marine life.

Less predictably, global heating has made the oceans more stable, with discrete, stratified layers that resist mixing. And that could be very bad news, because it could make the blue water that covers 70% of the planet less effective at absorbing atmospheric heat and thus mitigating climate change.

And ever-warmer sea temperatures could have another unwelcome impact: as temperatures rise, levels of dissolved oxygen fall. And that could make it difficult for some sea creatures to breathe.

The oceans play a vital role in the water, energy and carbon cycles upon which all life depends. In 2010, demographers counted 1.9 billion people living within 100kms of the sea and less than 100 metres above sea level: that is 28% of all humanity. Many of them are crowded into 17 megacities with populations of more than 5 million people each. For many, the sea is the neighbourhood.

European researchers warn, in a new and detailed report on the state of the oceans from 1993 to 2010, that the rise in sea temperatures in the Mediterranean is without precedent, and the largest rise of all has been measured in the Arctic Ocean.

“Human society has always been dependent on the seas. Failure to reach good environmental status for our seas and oceans is not an option”

They also call as a matter of urgency for comprehensive and systematic monitoring of the ocean. “Human society has always been dependent on the seas,” they warn. “Failure to reach good environmental status for our seas and oceans is not an option.”

Chinese and US scientists report in the journal Nature Climate Change that − beyond reports of stronger winds and waves and ever more intense tropical cyclones − the rise in atmospheric temperatures has fundamentally altered oceanic temperatures and salinity, with a paradoxical effect: the seas have become more stable. Warm and therefore less dense surface water lies upon colder, more saline and denser waters at depth, to limit overall mixing.

Since 1960, the upper 2000 metres of the oceans have become 5% more stratified, and the top 150 metres 18% more stratified.

“The same process, global warming, is both making the atmosphere less stable and the oceans more stable. Water near the ocean’s surface is warming faster than the water below. That makes the oceans become more stable,” said Michael Mann of Penn State University in Pennsylvania, one of the team.

“The ability of the oceans to bury heat from the atmosphere and mitigate global warming is made more difficult when the ocean becomes more stratified and there is less mixing. Less downward mixing of warming waters means the ocean surface warms even faster, leading, for example, to more powerful hurricanes. Global climate models underestimate these trends.”

Struggle for survival

Warmer temperatures don’t just make the oceans more stable, they may make living conditions more uncomfortable or even impossible for some of the sea’s citizenry.

US researchers report in the journal Nature that they looked at the physiological challenge of oxygen and energy demands faced by 145 marine species − including shrimps, catsharks and sea squirts − to find that many are already under pressure.

“Organisms today are living right up to the warmest temperatures possible that will supply them with adequate oxygen for their activity level – so higher temperatures are immediately going to affect their ability to get enough oxygen,” said Curtis Deutsch of the University of Washington.

“In response to warming, their activity level is going to be restricted or their habitat is going to start shrinking. It’s not like they are going to be fine and carry on.” − Climate News Network

Climate warming brings hotter seas. The waters mix less. And conditions for some creatures could grow increasingly stifling.

LONDON, 9 October, 2020 − Climate change has led to hotter seas across the world: in 2018 European water temperatures reached record levels, and a marine heatwave in the north-east Pacific devastated marine life.

Less predictably, global heating has made the oceans more stable, with discrete, stratified layers that resist mixing. And that could be very bad news, because it could make the blue water that covers 70% of the planet less effective at absorbing atmospheric heat and thus mitigating climate change.

And ever-warmer sea temperatures could have another unwelcome impact: as temperatures rise, levels of dissolved oxygen fall. And that could make it difficult for some sea creatures to breathe.

The oceans play a vital role in the water, energy and carbon cycles upon which all life depends. In 2010, demographers counted 1.9 billion people living within 100kms of the sea and less than 100 metres above sea level: that is 28% of all humanity. Many of them are crowded into 17 megacities with populations of more than 5 million people each. For many, the sea is the neighbourhood.

European researchers warn, in a new and detailed report on the state of the oceans from 1993 to 2010, that the rise in sea temperatures in the Mediterranean is without precedent, and the largest rise of all has been measured in the Arctic Ocean.

“Human society has always been dependent on the seas. Failure to reach good environmental status for our seas and oceans is not an option”

They also call as a matter of urgency for comprehensive and systematic monitoring of the ocean. “Human society has always been dependent on the seas,” they warn. “Failure to reach good environmental status for our seas and oceans is not an option.”

Chinese and US scientists report in the journal Nature Climate Change that − beyond reports of stronger winds and waves and ever more intense tropical cyclones − the rise in atmospheric temperatures has fundamentally altered oceanic temperatures and salinity, with a paradoxical effect: the seas have become more stable. Warm and therefore less dense surface water lies upon colder, more saline and denser waters at depth, to limit overall mixing.

Since 1960, the upper 2000 metres of the oceans have become 5% more stratified, and the top 150 metres 18% more stratified.

“The same process, global warming, is both making the atmosphere less stable and the oceans more stable. Water near the ocean’s surface is warming faster than the water below. That makes the oceans become more stable,” said Michael Mann of Penn State University in Pennsylvania, one of the team.

“The ability of the oceans to bury heat from the atmosphere and mitigate global warming is made more difficult when the ocean becomes more stratified and there is less mixing. Less downward mixing of warming waters means the ocean surface warms even faster, leading, for example, to more powerful hurricanes. Global climate models underestimate these trends.”

Struggle for survival

Warmer temperatures don’t just make the oceans more stable, they may make living conditions more uncomfortable or even impossible for some of the sea’s citizenry.

US researchers report in the journal Nature that they looked at the physiological challenge of oxygen and energy demands faced by 145 marine species − including shrimps, catsharks and sea squirts − to find that many are already under pressure.

“Organisms today are living right up to the warmest temperatures possible that will supply them with adequate oxygen for their activity level – so higher temperatures are immediately going to affect their ability to get enough oxygen,” said Curtis Deutsch of the University of Washington.

“In response to warming, their activity level is going to be restricted or their habitat is going to start shrinking. It’s not like they are going to be fine and carry on.” − Climate News Network

Wilder shores of science yield new ideas on climate

New ideas on climate mean earthquake scientists know more about global heating and astronomers worry over rising warmth.

LONDON, 22 September, 2020 – Science has extended research into the global heating crisis, thanks to new ideas on climate. And, conversely, climate change has extended science in unexpected ways.

Seismologists believe they may have a new way to take the temperature of the world’s oceans. And astronomers focused on distant galaxies have unwittingly amassed a 30-year record of climate change in the Earth’s own atmosphere.

Both discoveries, in the same week, start with the simple physics of sight and sound. US and Chinese researchers report in the journal Science that records from submarine earthquakes could now deliver an unexpected way of measuring the warmth of the water.

Submarine earthquakes create a pattern of sound that can be transmitted immense distances through the ocean without much weakening. And, since the speed of sound in water increases as the temperature of the water rises, the length of time the sound takes to reach detector equipment is itself an indicator of ocean temperature.

Seismologists know – from waves travelling through the Earth’s crust and its deep interior – when and where the earthquakes happen. Seismic waves sprint through rock at rates measured in kilometres per second. Sound waves propagate through oceans at rates measured in kilometres per hour.

“It is of prime importance that astronomy uses its unique perspective to claim this simple fact: there is no planet B”

Just as the differences between the speed of lightning and the speed of thunder can establish the distance of an electrical storm, so if researchers know the time and distance of the sea floor event, they have a way of taking the temperature of the water. The constant rumbling of a living planet could offer a new set of easily assembled readings.

“The key is that we use repeating earthquakes – earthquakes that happen again and again in the same place,” said Wenbo Wu, of the California Institute of Technology, who led the Science study.

“We’re looking at earthquakes that occur off Sumatra in Indonesia, and we measure when they arrive in the central Indian Ocean. It takes about half an hour for them to travel that distance, with water temperature causing about one tenth of a second difference. It’s a very small fractional change, but we can measure it.”

The finding matters because – although humans have been recording local ground and air temperatures for at least 300 years, and worldwide for more than a century – it is much harder to be sure about ocean temperatures: the seas cover 70% of the planet, to an average depth of more than 3 kms, and the temperatures vary with both depth and latitude.

Sound goes deep

Oceanographic research is costly, technically challenging, and uneven. Researchers know that the oceans are responding to climate change driven by global heating as a consequence of greenhouse gas emissions: they do not, however, yet have an assured measure of how much heat the oceans have absorbed, and will go on absorbing.

“The ocean plays a role in the rate that the climate is changing,” said Jörn Callies of Caltech, a co-author. “The ocean is the main reservoir of energy in the climate system, and the deep ocean in particular is important to monitor. One advantage of our method is that the sound waves sample depths below 2,000 metres where there are very few conventional measurements.”

Paradoxically, astronomers need to know a great deal about the first few thousand metres of planet Earth as they peer into the furthest reaches of the universe: what they see and how well they see it is affected by atmospheric temperature, turbulence and moisture.

As ground-based telescopes become bigger and more sensitive – the Extremely Large Telescope now under construction at Paranal in northern Chile will collect light with a mirror 39 metres across – so do the challenges of eliminating the atmospheric turbulence that puts the twinkle in the stars of the night sky: cold air and warm air refract light differently, to create a blur. The bigger the telescope, the greater will be the problem of blur.

For three decades, scientists in the highest and driest part of Chile have been recording subtle and not so subtle atmospheric change. And according to the journal Nature Astronomy, climate change is already beginning to affect astronomical research, and will go on creating problems.

Terrestrial disturbances

“The data showed a 1.5°C increase in near-ground temperature over the last four decades at the Paranal Observatory,” said Susanne Crewell of the University of Cologne. “This is slightly higher than the worldwide average of 1°C since the pre-industrial age.”

Average wind speeds – wind also affects the precision of observations – have increased by 3 or 4 metres per second in the same period. Humidity, too, is expected to change as the world moves to what could be a 4°C average rise in temperature by the century’s end.

The message is that conditions on Earth can disturb the observations and mask the understanding of events billions of light years away and billions of years ago. Astronomers, too, need to sound the alarm about climate change, she and her colleagues write.

“To do so, a massive cultural shift is needed,” they conclude, “and it is of prime importance that astronomy uses its unique perspective to claim this simple fact: there is no planet B.” – Climate News Network

New ideas on climate mean earthquake scientists know more about global heating and astronomers worry over rising warmth.

LONDON, 22 September, 2020 – Science has extended research into the global heating crisis, thanks to new ideas on climate. And, conversely, climate change has extended science in unexpected ways.

Seismologists believe they may have a new way to take the temperature of the world’s oceans. And astronomers focused on distant galaxies have unwittingly amassed a 30-year record of climate change in the Earth’s own atmosphere.

Both discoveries, in the same week, start with the simple physics of sight and sound. US and Chinese researchers report in the journal Science that records from submarine earthquakes could now deliver an unexpected way of measuring the warmth of the water.

Submarine earthquakes create a pattern of sound that can be transmitted immense distances through the ocean without much weakening. And, since the speed of sound in water increases as the temperature of the water rises, the length of time the sound takes to reach detector equipment is itself an indicator of ocean temperature.

Seismologists know – from waves travelling through the Earth’s crust and its deep interior – when and where the earthquakes happen. Seismic waves sprint through rock at rates measured in kilometres per second. Sound waves propagate through oceans at rates measured in kilometres per hour.

“It is of prime importance that astronomy uses its unique perspective to claim this simple fact: there is no planet B”

Just as the differences between the speed of lightning and the speed of thunder can establish the distance of an electrical storm, so if researchers know the time and distance of the sea floor event, they have a way of taking the temperature of the water. The constant rumbling of a living planet could offer a new set of easily assembled readings.

“The key is that we use repeating earthquakes – earthquakes that happen again and again in the same place,” said Wenbo Wu, of the California Institute of Technology, who led the Science study.

“We’re looking at earthquakes that occur off Sumatra in Indonesia, and we measure when they arrive in the central Indian Ocean. It takes about half an hour for them to travel that distance, with water temperature causing about one tenth of a second difference. It’s a very small fractional change, but we can measure it.”

The finding matters because – although humans have been recording local ground and air temperatures for at least 300 years, and worldwide for more than a century – it is much harder to be sure about ocean temperatures: the seas cover 70% of the planet, to an average depth of more than 3 kms, and the temperatures vary with both depth and latitude.

Sound goes deep

Oceanographic research is costly, technically challenging, and uneven. Researchers know that the oceans are responding to climate change driven by global heating as a consequence of greenhouse gas emissions: they do not, however, yet have an assured measure of how much heat the oceans have absorbed, and will go on absorbing.

“The ocean plays a role in the rate that the climate is changing,” said Jörn Callies of Caltech, a co-author. “The ocean is the main reservoir of energy in the climate system, and the deep ocean in particular is important to monitor. One advantage of our method is that the sound waves sample depths below 2,000 metres where there are very few conventional measurements.”

Paradoxically, astronomers need to know a great deal about the first few thousand metres of planet Earth as they peer into the furthest reaches of the universe: what they see and how well they see it is affected by atmospheric temperature, turbulence and moisture.

As ground-based telescopes become bigger and more sensitive – the Extremely Large Telescope now under construction at Paranal in northern Chile will collect light with a mirror 39 metres across – so do the challenges of eliminating the atmospheric turbulence that puts the twinkle in the stars of the night sky: cold air and warm air refract light differently, to create a blur. The bigger the telescope, the greater will be the problem of blur.

For three decades, scientists in the highest and driest part of Chile have been recording subtle and not so subtle atmospheric change. And according to the journal Nature Astronomy, climate change is already beginning to affect astronomical research, and will go on creating problems.

Terrestrial disturbances

“The data showed a 1.5°C increase in near-ground temperature over the last four decades at the Paranal Observatory,” said Susanne Crewell of the University of Cologne. “This is slightly higher than the worldwide average of 1°C since the pre-industrial age.”

Average wind speeds – wind also affects the precision of observations – have increased by 3 or 4 metres per second in the same period. Humidity, too, is expected to change as the world moves to what could be a 4°C average rise in temperature by the century’s end.

The message is that conditions on Earth can disturb the observations and mask the understanding of events billions of light years away and billions of years ago. Astronomers, too, need to sound the alarm about climate change, she and her colleagues write.

“To do so, a massive cultural shift is needed,” they conclude, “and it is of prime importance that astronomy uses its unique perspective to claim this simple fact: there is no planet B.” – Climate News Network

Seas and forests are muddying the carbon budget

As climates change, forests may not absorb more carbon as expected. But a new carbon budget could appeal to the oceans.

LONDON, 18 September 2020 – Two new studies could throw long-term climate forecasts into confusion. The planetary carbon budget – the all-important traffic of life’s first element between rocks, water, atmosphere and living things – that underpins planetary temperatures and maintains a stable climate needs a rethink.

A warming climate makes trees grow faster. The awkward finding is that  faster-growing trees die younger. Therefore they must surrender their carbon back to the atmosphere quicker.

So tomorrow’s forests may not be quite such reliable long-term banks of carbon pumped into the atmosphere as a consequence of profligate fossil fuel use by human economies.

The more reassuring news is that the ocean – that’s almost three fourths of the planet’s surface – may absorb and store a lot more atmospheric carbon than previous estimates suggest.

All calculations about the future rate of global heating, and the potential consequences of climate change, rest upon the carbon budget.

Forest doubts

This is the intricate accounting of the mass of carbon in continuous circulation from air to plant to animal and then to shell, skeleton and sediment, and the expected flow of carbon emissions from the combustion of fossil fuels stored hundreds of millions of years ago, and exhumed in the last two centuries.

To make sense of the factors at work, climate scientists have to make calculations about all the carbon stored in the permafrost, in the soils, in the forests, dissolved in the oceans, free in the atmosphere and being released from power station chimneys, vehicle exhausts and ploughed or scorched land.

But for decades, one component of the equation has been automatically accepted: more forests must mean more carbon absorbed, and better protected natural forests would store the most carbon, the most efficiently.

Now a new report in the journal Nature Communications introduces some doubt into this cornerstone of the carbon budget. In an already warming world, much more of the carbon stored in tomorrow’s forests might find its way back into the atmosphere.

Researchers looked at 200,000 tree ring records from 82 tree species from sites around the planet. They found what they describe as trade-offs that are near universal: faster-growing trees have shorter lives.

“There is likely to be a timelag before we see the worst of the potential loss of carbon stocks from increases in tree mortality”

This was true in cool climates and warm ones, and in all species. So the hope that natural vegetation will respond to warmer temperatures by absorbing even more carbon becomes insecure, especially if it means that the more vigorous growth means simply swifter death and decay.

“Our modeling suggests that there is likely to be a timelag before we see the worst of the potential loss of carbon stocks from increases in tree mortality,” said Roel Brienen of the University of Leeds in the UK, who led the research. “They estimate that global increases in tree death don’t kick in until after sites show accelerated growth.”

All such research is provisional: the findings gain currency only when supported by other teams using different approaches. So it has yet to be confirmed.

But recent studies have suggested that climate change has already begun to complicate calculations. Just in recent months, research teams have found that forest trees are growing shorter and dying younger; that higher temperatures may affect plant germination; and that forests already hit by drought may start surrendering carbon more swiftly than they absorb it. Planting more trees is not an alternative to reducing greenhouse gas emissions.

On the other hand, the carbon budget may still make sense: the oceans may be responding to ever-higher concentrations of carbon dioxide by absorbing more from the atmosphere, which also makes the oceans more acidic, which is not necessarily helpful.

Oceans’ effect

All such calculations are based on sea surface temperatures. Gases such as carbon dioxide and oxygen dissolve well in colder water, not so well in warm lagoons and tropical tides.

But a British group reports in the same journal that calculations so far may have been under-estimates. This is because, on balance, researchers have tended to ignore the small difference between the temperatures at the surface, and a few metres down, where the measurements of dissolved greenhouse gas were actually made.

A team from the University of Exeter worked from a global database to make new estimates of the oceans’ appetite for carbon between 1992 and 2018.

“We used satellite data to correct for these temperature differences, and when we do that, it makes a big difference – we get a substantially larger flux going into the ocean,” said Andrew Watson, who led the study.

“The difference in ocean uptake we calculate amounts to 10% of global fossil fuel emissions.” – Climate News Network

As climates change, forests may not absorb more carbon as expected. But a new carbon budget could appeal to the oceans.

LONDON, 18 September 2020 – Two new studies could throw long-term climate forecasts into confusion. The planetary carbon budget – the all-important traffic of life’s first element between rocks, water, atmosphere and living things – that underpins planetary temperatures and maintains a stable climate needs a rethink.

A warming climate makes trees grow faster. The awkward finding is that  faster-growing trees die younger. Therefore they must surrender their carbon back to the atmosphere quicker.

So tomorrow’s forests may not be quite such reliable long-term banks of carbon pumped into the atmosphere as a consequence of profligate fossil fuel use by human economies.

The more reassuring news is that the ocean – that’s almost three fourths of the planet’s surface – may absorb and store a lot more atmospheric carbon than previous estimates suggest.

All calculations about the future rate of global heating, and the potential consequences of climate change, rest upon the carbon budget.

Forest doubts

This is the intricate accounting of the mass of carbon in continuous circulation from air to plant to animal and then to shell, skeleton and sediment, and the expected flow of carbon emissions from the combustion of fossil fuels stored hundreds of millions of years ago, and exhumed in the last two centuries.

To make sense of the factors at work, climate scientists have to make calculations about all the carbon stored in the permafrost, in the soils, in the forests, dissolved in the oceans, free in the atmosphere and being released from power station chimneys, vehicle exhausts and ploughed or scorched land.

But for decades, one component of the equation has been automatically accepted: more forests must mean more carbon absorbed, and better protected natural forests would store the most carbon, the most efficiently.

Now a new report in the journal Nature Communications introduces some doubt into this cornerstone of the carbon budget. In an already warming world, much more of the carbon stored in tomorrow’s forests might find its way back into the atmosphere.

Researchers looked at 200,000 tree ring records from 82 tree species from sites around the planet. They found what they describe as trade-offs that are near universal: faster-growing trees have shorter lives.

“There is likely to be a timelag before we see the worst of the potential loss of carbon stocks from increases in tree mortality”

This was true in cool climates and warm ones, and in all species. So the hope that natural vegetation will respond to warmer temperatures by absorbing even more carbon becomes insecure, especially if it means that the more vigorous growth means simply swifter death and decay.

“Our modeling suggests that there is likely to be a timelag before we see the worst of the potential loss of carbon stocks from increases in tree mortality,” said Roel Brienen of the University of Leeds in the UK, who led the research. “They estimate that global increases in tree death don’t kick in until after sites show accelerated growth.”

All such research is provisional: the findings gain currency only when supported by other teams using different approaches. So it has yet to be confirmed.

But recent studies have suggested that climate change has already begun to complicate calculations. Just in recent months, research teams have found that forest trees are growing shorter and dying younger; that higher temperatures may affect plant germination; and that forests already hit by drought may start surrendering carbon more swiftly than they absorb it. Planting more trees is not an alternative to reducing greenhouse gas emissions.

On the other hand, the carbon budget may still make sense: the oceans may be responding to ever-higher concentrations of carbon dioxide by absorbing more from the atmosphere, which also makes the oceans more acidic, which is not necessarily helpful.

Oceans’ effect

All such calculations are based on sea surface temperatures. Gases such as carbon dioxide and oxygen dissolve well in colder water, not so well in warm lagoons and tropical tides.

But a British group reports in the same journal that calculations so far may have been under-estimates. This is because, on balance, researchers have tended to ignore the small difference between the temperatures at the surface, and a few metres down, where the measurements of dissolved greenhouse gas were actually made.

A team from the University of Exeter worked from a global database to make new estimates of the oceans’ appetite for carbon between 1992 and 2018.

“We used satellite data to correct for these temperature differences, and when we do that, it makes a big difference – we get a substantially larger flux going into the ocean,” said Andrew Watson, who led the study.

“The difference in ocean uptake we calculate amounts to 10% of global fossil fuel emissions.” – Climate News Network

Hotter oceans harm seabed life survival prospects

Seabed life is tough: only the young can migrate. But climate change is taking many of them the wrong way.

LONDON, 14 September, 2020 – It can be hard being a junior part of seabed life – a young starfish, say, or an adolescent worm. Down in the ocean depths, the environment is conspiring against you.

Marine biologists have just identified – and explained – a climate change paradox: while most fish are migrating towards the poles as the world’s oceans warm, one part of a potentially valuable commercial fishery is heading in the wrong direction – and perhaps to extinction.

Why? Once again, the finger of suspicion points to global climate change, and its impact on ocean tides and currents.

Throughout this century, researchers have repeatedly confirmed a pattern of ocean warming – and acidification – driven by ever-rising ratios of carbon dioxide in the atmosphere; a pattern that could affect both established commercial fishing industries and ocean life as a whole.

Tropical fish have been shifting away from the equator; further north and south, pelagic (open-ocean) and demersal (seabed-dwelling) fish have been seeking more suitable grounds. Warmer seas can affect spawning patterns.

“As the seas continue to warm, spawning times will get ever earlier and the currents will sweep many of the next generation to oblivion”

But the ocean is a vast living space, and the speed at which it warms tends to vary with depth.

US researchers report in the journal Nature Climate Change that they worked through 60 years of data on 50 species of benthic invertebrates – creatures without backbones that dwell on the sea floor – to find that the populations of four-fifths of these had begun to disappear from the shelves and fishing grounds of the Georges Bank and the outer shelf that runs from New Jersey and east of the Delmarva Peninsula occupied by the states of Delaware, Maryland and Virginia.

More to the point, they identified the mechanism that had begun to limit life on the submarine sediments. Bottom-dwellers – shellfish, snails, starfish, worms and so on – can’t migrate: they are stuck where they are. But their larvae can, and at spawning time the infant shellfish are at the mercy of the ocean currents.

The waters of the north-east Atlantic coast are warming at three times the global average rate. Warming has affected the time at which benthic invertebrates spawn. Because the larvae appear earlier in spring and summer, they are swept away by currents they would not encounter in a cooler, more stable world.

And these currents, driven by river discharge and seasonal winds, tend to bring them south-west and inshore, where waters are warmer and the larvae are even less likely to survive.

Nowhere to go

Those adults that remain are stuck where they are: as the seas continue to warm, spawning times will get ever earlier and the currents will sweep many of the next generation to oblivion.

These bottom-dwelling denizens could survive, if they could colonise cooler waters. Instead they are condemned to a submarine version of what terrestrial biologists call the elevator to extinction: on land, hotter temperatures drive birds and butterflies and plants ever further uphill: in the end, nearer the summit, there’s nowhere to go.

The researchers, from Rutgers University in New Brunswick, call it the downwelling effect, and identify a paradox: as the area habitable by bottom-dwellers gets bigger, their ranges dwindle.

The finding so far is true only for the north-east Atlantic waters, and some species seem less affected. Scallops could flourish, because they spawn at a wider range of temperatures. But clams and mussels are adapted to low temperatures, and their ranges have warmed and contracted.

And, the scientists warn, as global heating reduces yields from traditional fisheries, the seafood industry is likely to rely increasingly on shellfish. But this industry, too, is vulnerable to ocean change. – Climate News Network

Seabed life is tough: only the young can migrate. But climate change is taking many of them the wrong way.

LONDON, 14 September, 2020 – It can be hard being a junior part of seabed life – a young starfish, say, or an adolescent worm. Down in the ocean depths, the environment is conspiring against you.

Marine biologists have just identified – and explained – a climate change paradox: while most fish are migrating towards the poles as the world’s oceans warm, one part of a potentially valuable commercial fishery is heading in the wrong direction – and perhaps to extinction.

Why? Once again, the finger of suspicion points to global climate change, and its impact on ocean tides and currents.

Throughout this century, researchers have repeatedly confirmed a pattern of ocean warming – and acidification – driven by ever-rising ratios of carbon dioxide in the atmosphere; a pattern that could affect both established commercial fishing industries and ocean life as a whole.

Tropical fish have been shifting away from the equator; further north and south, pelagic (open-ocean) and demersal (seabed-dwelling) fish have been seeking more suitable grounds. Warmer seas can affect spawning patterns.

“As the seas continue to warm, spawning times will get ever earlier and the currents will sweep many of the next generation to oblivion”

But the ocean is a vast living space, and the speed at which it warms tends to vary with depth.

US researchers report in the journal Nature Climate Change that they worked through 60 years of data on 50 species of benthic invertebrates – creatures without backbones that dwell on the sea floor – to find that the populations of four-fifths of these had begun to disappear from the shelves and fishing grounds of the Georges Bank and the outer shelf that runs from New Jersey and east of the Delmarva Peninsula occupied by the states of Delaware, Maryland and Virginia.

More to the point, they identified the mechanism that had begun to limit life on the submarine sediments. Bottom-dwellers – shellfish, snails, starfish, worms and so on – can’t migrate: they are stuck where they are. But their larvae can, and at spawning time the infant shellfish are at the mercy of the ocean currents.

The waters of the north-east Atlantic coast are warming at three times the global average rate. Warming has affected the time at which benthic invertebrates spawn. Because the larvae appear earlier in spring and summer, they are swept away by currents they would not encounter in a cooler, more stable world.

And these currents, driven by river discharge and seasonal winds, tend to bring them south-west and inshore, where waters are warmer and the larvae are even less likely to survive.

Nowhere to go

Those adults that remain are stuck where they are: as the seas continue to warm, spawning times will get ever earlier and the currents will sweep many of the next generation to oblivion.

These bottom-dwelling denizens could survive, if they could colonise cooler waters. Instead they are condemned to a submarine version of what terrestrial biologists call the elevator to extinction: on land, hotter temperatures drive birds and butterflies and plants ever further uphill: in the end, nearer the summit, there’s nowhere to go.

The researchers, from Rutgers University in New Brunswick, call it the downwelling effect, and identify a paradox: as the area habitable by bottom-dwellers gets bigger, their ranges dwindle.

The finding so far is true only for the north-east Atlantic waters, and some species seem less affected. Scallops could flourish, because they spawn at a wider range of temperatures. But clams and mussels are adapted to low temperatures, and their ranges have warmed and contracted.

And, the scientists warn, as global heating reduces yields from traditional fisheries, the seafood industry is likely to rely increasingly on shellfish. But this industry, too, is vulnerable to ocean change. – Climate News Network

Hotter oceans make the tropics expand polewards

The tropical climate zones are not just warmer, they now cover more of the planet. Blame it on steadily hotter oceans.

LONDON, 27 August, 2020 – The tropics are on the march and US and German scientists think they know why: hotter oceans have taken control.

The parched, arid fringes of the hot, moist conditions that nourish the equatorial forest band around the middle of the globe are moving, unevenly, further north and south in response to climate change.

And the role of the ocean is made even more dramatic in the southern hemisphere: because the ocean south of the equator is so much bigger than in the north, the southward shift of the parched zone is even more pronounced.

Across the globe, things don’t look good for places like California, which has already suffered some of its worst droughts and fires on record, and  Australia, where drought and fire if possible have been even worse.

In the past century or so, carbon dioxide levels in the atmosphere have risen from what was once a stable average of 285 parts per million to more than 400 ppm, and global average temperatures are now at least 1°C higher than they have been for most of human history.

“We demonstrate that the enhanced subtropical ocean warming is independent from the natural climate oscillations. This is a result of global warming”

And although the fastest and most dramatic changes in the world have been in the coldest zones – and particularly the Arctic – the tropics, too, have begun to feel the heat.

Researchers have observed tropical fish moving into cooler waters; they have warned that some tropical plant species may soon find temperatures too high for germination; they have mapped tropical cyclones hitting further north and south with time, and doing more damage; and they have seen evidence that tropical diseases could soon advance even into temperate Europe.

But although satellite observations have revealed that the tropical climate zone has expanded beyond the formal limits known as the Tropics of Capricorn and Cancer, and is doing so at somewhere between a quarter and half a degree of latitude each decade, no one has been able to work out why the shift is more pronounced in the southern half of the globe.

Now a new study in the Journal of Geophysical Research: Atmospheres offers an answer. The expansion of the tropics has been driven by ocean warming.

And if that expansion is more obvious in the southern hemisphere, it is because there is more sea to have more impact.

Clear link

Researchers analysed water temperature patterns in the great ocean gyres, those giant circular currents that take warm waters to the poles and return cold water to the equatorial regions.

They matched satellite readings from 1982 – the first year in the series of measurements – with data from 2018, and compared these to measurements of tropical zone expansion.

The connection was clear: excess heat that had been building up in the subtropical oceans ever since global warming began had driven both tropical edges and ocean gyres towards the poles.

That is, the shift in the tropics wasn’t just one of those slow pulses of expansion and retraction, of cyclic change, that happen in a complex world. And more precisely, the tropics were expanding more clearly in those places where the gyres moved poleward.

“We demonstrate that the enhanced subtropical ocean warming is independent from the natural climate oscillations,” said Hu Yang of the Alfred Wegener Institute in Bremerhaven, Germany, who led the research. “This is a result of global warming.” – Climate News Network

The tropical climate zones are not just warmer, they now cover more of the planet. Blame it on steadily hotter oceans.

LONDON, 27 August, 2020 – The tropics are on the march and US and German scientists think they know why: hotter oceans have taken control.

The parched, arid fringes of the hot, moist conditions that nourish the equatorial forest band around the middle of the globe are moving, unevenly, further north and south in response to climate change.

And the role of the ocean is made even more dramatic in the southern hemisphere: because the ocean south of the equator is so much bigger than in the north, the southward shift of the parched zone is even more pronounced.

Across the globe, things don’t look good for places like California, which has already suffered some of its worst droughts and fires on record, and  Australia, where drought and fire if possible have been even worse.

In the past century or so, carbon dioxide levels in the atmosphere have risen from what was once a stable average of 285 parts per million to more than 400 ppm, and global average temperatures are now at least 1°C higher than they have been for most of human history.

“We demonstrate that the enhanced subtropical ocean warming is independent from the natural climate oscillations. This is a result of global warming”

And although the fastest and most dramatic changes in the world have been in the coldest zones – and particularly the Arctic – the tropics, too, have begun to feel the heat.

Researchers have observed tropical fish moving into cooler waters; they have warned that some tropical plant species may soon find temperatures too high for germination; they have mapped tropical cyclones hitting further north and south with time, and doing more damage; and they have seen evidence that tropical diseases could soon advance even into temperate Europe.

But although satellite observations have revealed that the tropical climate zone has expanded beyond the formal limits known as the Tropics of Capricorn and Cancer, and is doing so at somewhere between a quarter and half a degree of latitude each decade, no one has been able to work out why the shift is more pronounced in the southern half of the globe.

Now a new study in the Journal of Geophysical Research: Atmospheres offers an answer. The expansion of the tropics has been driven by ocean warming.

And if that expansion is more obvious in the southern hemisphere, it is because there is more sea to have more impact.

Clear link

Researchers analysed water temperature patterns in the great ocean gyres, those giant circular currents that take warm waters to the poles and return cold water to the equatorial regions.

They matched satellite readings from 1982 – the first year in the series of measurements – with data from 2018, and compared these to measurements of tropical zone expansion.

The connection was clear: excess heat that had been building up in the subtropical oceans ever since global warming began had driven both tropical edges and ocean gyres towards the poles.

That is, the shift in the tropics wasn’t just one of those slow pulses of expansion and retraction, of cyclic change, that happen in a complex world. And more precisely, the tropics were expanding more clearly in those places where the gyres moved poleward.

“We demonstrate that the enhanced subtropical ocean warming is independent from the natural climate oscillations,” said Hu Yang of the Alfred Wegener Institute in Bremerhaven, Germany, who led the research. “This is a result of global warming.” – Climate News Network

Changing oceans reveal clear human thumbprint

Climate heating must have already begun to result in changing oceans. The next step is to confirm and monitor this change.

LONDON, 26 August, 2020 – Humankind has already begun to reshape the biggest available living space on the planet and to leave its mark in the changing oceans.

New research suggests that somewhere between 20% and 55% of the Atlantic, Pacific and Indian Oceans now have temperatures and salt levels that should be measurably different because of climate change driven by profligate human combustion of fossil fuels.

And forecasts suggest that by mid-century the scale of human impact will only have increased – to between 40% and 60%. By 2080, human impact on the oceans will have begun to change between 55% and 80% of the blue planet.

Although the researchers – they report in the journal Nature Climate Change – have based their predictions on computer models, they are confident that the thumbprint of human-induced climate change began to leave its mark on the seas of the Southern Hemisphere as long ago as the 1980s.

“We have been detecting ocean temperature change at the surface due to climate change for several decades now,” said Eric Guilyardi, of the University of Reading in the UK and the Laboratory of Oceanography and Climate in Paris, France.

“Our results highlight the importance of maintaining and augmenting an ocean observing system capable of detecting and monitoring persistent anthropogenic changes”

“But changes in vast areas of the ocean, particularly deeper parts, are much more challenging to detect.”

The problem of measurement is simple: the ocean is enormous. It covers 70% of the planet to an average depth of 3.7 kms. It defines the planet.

It is almost certainly where life on Earth first emerged; it was life’s only home for the first three billion years.

And it is in a state of constant change, constantly evaporating, and continually replenished with freshwater from rainfall, river flow and melting polar ice. So temperature and salinity change naturally, and with the seasons, and with much longer cyclic swings driven by the atmosphere.

Scientists have been measuring surface conditions for many decades. The ocean at depth is a bit more of a challenge. The question the researchers put was a simple one: could temperature and salinity levels in parts of the ocean have risen or fallen higher or lower than they would in normal peaks and troughs?

Beyond natural variability

It’s not an easy question: oceanography is expensive, the ocean is huge, much of it has never been studied and the ways in which the ocean layers mix is still a bit of a puzzle.

So the scientists started with two models, with and without the impact of human action. They then worked on an analysis of salt levels and temperatures to detect significant change, and then tried to predict the dates at which this change ought to declare itself.

Their readings tell them that changes beyond natural variability in the northern hemisphere – all the seas from the Arctic Ocean to the equatorial waters – could have emerged between 2010 and 2030. That is, change is already happening.

Their simulations also predicted that whatever shifts occurred at depth in the temperature and chemistry of the southern oceans, these could have been identified up to 40 years ago, had researchers had the technology, the funding, the people and the ships and submersibles to do so.

“Our results highlight the importance of maintaining and augmenting an ocean observing system capable of detecting and monitoring persistent anthropogenic changes,” they report. – Climate News Network

Climate heating must have already begun to result in changing oceans. The next step is to confirm and monitor this change.

LONDON, 26 August, 2020 – Humankind has already begun to reshape the biggest available living space on the planet and to leave its mark in the changing oceans.

New research suggests that somewhere between 20% and 55% of the Atlantic, Pacific and Indian Oceans now have temperatures and salt levels that should be measurably different because of climate change driven by profligate human combustion of fossil fuels.

And forecasts suggest that by mid-century the scale of human impact will only have increased – to between 40% and 60%. By 2080, human impact on the oceans will have begun to change between 55% and 80% of the blue planet.

Although the researchers – they report in the journal Nature Climate Change – have based their predictions on computer models, they are confident that the thumbprint of human-induced climate change began to leave its mark on the seas of the Southern Hemisphere as long ago as the 1980s.

“We have been detecting ocean temperature change at the surface due to climate change for several decades now,” said Eric Guilyardi, of the University of Reading in the UK and the Laboratory of Oceanography and Climate in Paris, France.

“Our results highlight the importance of maintaining and augmenting an ocean observing system capable of detecting and monitoring persistent anthropogenic changes”

“But changes in vast areas of the ocean, particularly deeper parts, are much more challenging to detect.”

The problem of measurement is simple: the ocean is enormous. It covers 70% of the planet to an average depth of 3.7 kms. It defines the planet.

It is almost certainly where life on Earth first emerged; it was life’s only home for the first three billion years.

And it is in a state of constant change, constantly evaporating, and continually replenished with freshwater from rainfall, river flow and melting polar ice. So temperature and salinity change naturally, and with the seasons, and with much longer cyclic swings driven by the atmosphere.

Scientists have been measuring surface conditions for many decades. The ocean at depth is a bit more of a challenge. The question the researchers put was a simple one: could temperature and salinity levels in parts of the ocean have risen or fallen higher or lower than they would in normal peaks and troughs?

Beyond natural variability

It’s not an easy question: oceanography is expensive, the ocean is huge, much of it has never been studied and the ways in which the ocean layers mix is still a bit of a puzzle.

So the scientists started with two models, with and without the impact of human action. They then worked on an analysis of salt levels and temperatures to detect significant change, and then tried to predict the dates at which this change ought to declare itself.

Their readings tell them that changes beyond natural variability in the northern hemisphere – all the seas from the Arctic Ocean to the equatorial waters – could have emerged between 2010 and 2030. That is, change is already happening.

Their simulations also predicted that whatever shifts occurred at depth in the temperature and chemistry of the southern oceans, these could have been identified up to 40 years ago, had researchers had the technology, the funding, the people and the ships and submersibles to do so.

“Our results highlight the importance of maintaining and augmenting an ocean observing system capable of detecting and monitoring persistent anthropogenic changes,” they report. – Climate News Network

Oceans’ plastic tide may be far larger than thought

Artificial fibres now go everywhere. The oceans’ plastic tide may reach their whole depth, entering marine life and people.

LONDON, 20 August, 2020 − The world’s seas could be home to a vast reservoir of hitherto unidentified pollution, the growing burden of the oceans’ plastic tide.

Up to 21 million tonnes of tiny and invisible plastic fibres could be floating in the first 200 metres of the Atlantic Ocean alone. And as British research exposed the scale of the problem, American chemists revealed that for the first time they had found microplastic fibres incorporated within human organ tissues.

A day or two later Dutch scientists demonstrated that plastic waste wasn’t simply a passive hazard to marine life: experiments showed that polluting plastic released chemicals into the stomachs of seabirds.

But first, the global problem. Oceanographers have known for decades that plastic waste had found its way into the sea: floating on the surface, it has reached the beaches of the remote Antarctic, been sampled in Arctic waters, been identified in the sediments on the sea floor and been ingested by marine creatures, from the smallest to the whale family.

Ominously, researchers warn that the sheer mass of plastic waste could multiply threefold in the decades to come. And, unlike all other forms of human pollution, plastic waste is here to stay, one day to form a permanent geological layer that will mark the Anthropocene era.

“Plastic is making its way into our bodies but very few studies have looked for it there. We don’t know whether this plastic is just a nuisance or whether it represents a human health hazard”

Scientists report in the journal Nature Communications that at 12 places along a 10,000 km north-south voyage in the Atlantic late in 2015, the waters were sampled for evidence of just three forms of plastic litter: polyethylene, polypropylene and polystyrene.

These samples were taken at depths of 10 metres below the surface, between 10 and 30 metres below what oceanographers call the mixed layer, and then 100 metres even deeper.

They then looked for fragments of the three plastics right down to the scale of 25 millionths of a metre, and began counting. They found up to 7,000 particles of all three types in a cubic metre of seawater.

Then they did the sums: people have been throwing plastic bags, packets, bottles, cups, nets and packaging away since 1950, and it has been getting into the Atlantic since 1950, with the estimated mass so far ranging from 17 million to 47 million tonnes.

The Atlantic has an average depth of 3000 metres. The discovery that the mass of plastic just in the upper 200 metres of one ocean lies somewhere between 12 and 21 million tonnes suggests that the flow of plastic into the seas everywhere may have been seriously under-estimated.

Missing measurement

“Previously, we couldn’t balance the mass of floating plastic we observed with the mass we thought had entered the ocean since 1950,” said Katsiaryna Pabortsava of the UK National Oceanography Centre, at Southampton, who led the study.

“This is because earlier studies hadn’t been measuring the concentrations of ‘invisible’ microplastic particles beneath the ocean surface. Our research is the first to have done this across the entire Atlantic, from the UK to the Falklands.”

Large plastic fragments disfigure the landscape and represent a direct threat to animals that mistake them for food.

Nobody yet knows how dangerous microplastic fibres might be, but if they are consumed by little animals they soon get concentrated in bigger predators, including the greatest predators of all: humans.

Scientists told the American Chemical Society – at a virtual meeting – that they had developed the techniques needed to identify microplastic fibres in 47 samples from donated lungs, liver, spleen and kidneys: that is, such fragments did more than simply pass through a gastrointestinal tract. They became part of human flesh.

Seabird vulnerability

“There’s evidence that plastic is making its way into our bodies but very few studies have looked for it there,” said Charles Rolsky of Arizona State University. “And at this point we don’t know whether this plastic is just a nuisance or whether it represents a human health hazard.”

Although plastic seems to be durable and indestructible, there may be evidence that it can react with biology. The journal Frontiers in Environmental Science reports that fragments of plastic, collected from beaches and incubated in natural oils from the stomachs of a seabird known as the northern fulmar – hunted for food in the Faroe Islands – eventually released chemicals.

These were agents that had been added in the process of making that plastic: among them flame retardants, stabilisers and plasticisers. Once again, there is no certainty that such releases would harm the birds, but some of these chemicals have been identified in other tests as hormone disruptors.

“I’ve been working on northern fulmars for almost 10 years,” said Susanne Kühn of Wageningen Marine Research in the Netherlands.

“As these seabirds ingest plastics regularly, and 93% of the fulmars from the North Sea have some plastic in their stomachs, it is important to understand the potential harm this could cause.” − Climate News Network

Artificial fibres now go everywhere. The oceans’ plastic tide may reach their whole depth, entering marine life and people.

LONDON, 20 August, 2020 − The world’s seas could be home to a vast reservoir of hitherto unidentified pollution, the growing burden of the oceans’ plastic tide.

Up to 21 million tonnes of tiny and invisible plastic fibres could be floating in the first 200 metres of the Atlantic Ocean alone. And as British research exposed the scale of the problem, American chemists revealed that for the first time they had found microplastic fibres incorporated within human organ tissues.

A day or two later Dutch scientists demonstrated that plastic waste wasn’t simply a passive hazard to marine life: experiments showed that polluting plastic released chemicals into the stomachs of seabirds.

But first, the global problem. Oceanographers have known for decades that plastic waste had found its way into the sea: floating on the surface, it has reached the beaches of the remote Antarctic, been sampled in Arctic waters, been identified in the sediments on the sea floor and been ingested by marine creatures, from the smallest to the whale family.

Ominously, researchers warn that the sheer mass of plastic waste could multiply threefold in the decades to come. And, unlike all other forms of human pollution, plastic waste is here to stay, one day to form a permanent geological layer that will mark the Anthropocene era.

“Plastic is making its way into our bodies but very few studies have looked for it there. We don’t know whether this plastic is just a nuisance or whether it represents a human health hazard”

Scientists report in the journal Nature Communications that at 12 places along a 10,000 km north-south voyage in the Atlantic late in 2015, the waters were sampled for evidence of just three forms of plastic litter: polyethylene, polypropylene and polystyrene.

These samples were taken at depths of 10 metres below the surface, between 10 and 30 metres below what oceanographers call the mixed layer, and then 100 metres even deeper.

They then looked for fragments of the three plastics right down to the scale of 25 millionths of a metre, and began counting. They found up to 7,000 particles of all three types in a cubic metre of seawater.

Then they did the sums: people have been throwing plastic bags, packets, bottles, cups, nets and packaging away since 1950, and it has been getting into the Atlantic since 1950, with the estimated mass so far ranging from 17 million to 47 million tonnes.

The Atlantic has an average depth of 3000 metres. The discovery that the mass of plastic just in the upper 200 metres of one ocean lies somewhere between 12 and 21 million tonnes suggests that the flow of plastic into the seas everywhere may have been seriously under-estimated.

Missing measurement

“Previously, we couldn’t balance the mass of floating plastic we observed with the mass we thought had entered the ocean since 1950,” said Katsiaryna Pabortsava of the UK National Oceanography Centre, at Southampton, who led the study.

“This is because earlier studies hadn’t been measuring the concentrations of ‘invisible’ microplastic particles beneath the ocean surface. Our research is the first to have done this across the entire Atlantic, from the UK to the Falklands.”

Large plastic fragments disfigure the landscape and represent a direct threat to animals that mistake them for food.

Nobody yet knows how dangerous microplastic fibres might be, but if they are consumed by little animals they soon get concentrated in bigger predators, including the greatest predators of all: humans.

Scientists told the American Chemical Society – at a virtual meeting – that they had developed the techniques needed to identify microplastic fibres in 47 samples from donated lungs, liver, spleen and kidneys: that is, such fragments did more than simply pass through a gastrointestinal tract. They became part of human flesh.

Seabird vulnerability

“There’s evidence that plastic is making its way into our bodies but very few studies have looked for it there,” said Charles Rolsky of Arizona State University. “And at this point we don’t know whether this plastic is just a nuisance or whether it represents a human health hazard.”

Although plastic seems to be durable and indestructible, there may be evidence that it can react with biology. The journal Frontiers in Environmental Science reports that fragments of plastic, collected from beaches and incubated in natural oils from the stomachs of a seabird known as the northern fulmar – hunted for food in the Faroe Islands – eventually released chemicals.

These were agents that had been added in the process of making that plastic: among them flame retardants, stabilisers and plasticisers. Once again, there is no certainty that such releases would harm the birds, but some of these chemicals have been identified in other tests as hormone disruptors.

“I’ve been working on northern fulmars for almost 10 years,” said Susanne Kühn of Wageningen Marine Research in the Netherlands.

“As these seabirds ingest plastics regularly, and 93% of the fulmars from the North Sea have some plastic in their stomachs, it is important to understand the potential harm this could cause.” − Climate News Network

End of Arctic sea ice by 2035 possible, study finds

How soon will the northern polar ocean be ice-free? New research expects the end of Arctic sea ice by 2035.

LONDON, 11 August, 2020 − The temperature of the Arctic matters to the entire world: it helps to keep the global climate fairly cool. Scientists now say that by 2035 there could be an end to Arctic sea ice.

The northern polar ocean’s sea ice is a crucial element in the Earth system: because it is highly reflective, it sends solar radiation back out into space. Once it’s melted, there’s no longer any protection for the darker water and rock beneath, and nothing to prevent them absorbing the incoming heat.

High temperatures in the Arctic during the last interglacial – the warm period around 127,000 years ago – have puzzled scientists for decades.

Now the UK Met Office’s Hadley Centre climate model has enabled an international research team to compare Arctic sea ice conditions during the last interglacial with the present day. Their findings are important for improving predictions of future sea ice change.

What is striking about the latest research is the date it suggests for a possible total melt − 2035. Many studies have thought a mid-century crisis likely, with another even carefully specifying 2044 as the year to watch. So a breathing space of only 15 years may surprise some experts.

“The prospect of loss of sea ice by 2035 should really be focussing all our minds on achieving a low-carbon world as soon as humanly feasible”

During spring and early summer shallow pools of water form on the surface of the Arctic sea ice. These “melt ponds” help to determine how much sunlight is absorbed by the ice and how much is reflected back into space. The new Hadley Centre model is the UK’s most advanced physical representation of the Earth’s climate and a critical tool for climate research, and it incorporates sea ice and melt ponds.

The researchers report their findings in the journal Nature Climate Change. Using the model to look at Arctic sea ice during the last interglacial, they concluded that the impact of intense springtime sunshine created many melt ponds, which played a crucial role in sea ice melt. A simulation of the future using the same model indicates that the Arctic may become sea ice-free by 2035.

The joint lead author of the team is Dr Maria Vittoria Guarino, an earth system modeller at the British Antarctic Survey (BAS) in Cambridge. She says: “High temperatures in the Arctic have puzzled scientists for decades. Unravelling this mystery was technically and scientifically challenging. For the first time, we can begin to see how the Arctic became sea ice-free during the last interglacial.

“The advances made in climate modelling mean that we can create a more accurate simulation of the Earth’s past climate which, in turn, gives us greater confidence in model predictions for the future.”

Dr Louise Sime, the group head of the palaeoclimate group and joint lead author at BAS, says: “We know the Arctic is undergoing significant changes as our planet warms. By understanding what happened during Earth’s last warm period we are in a better position to understand what will happen in the future.

Melt ponds crucial

“The prospect of loss of sea ice by 2035 should really be focussing all our minds on achieving a low-carbon world as soon as humanly feasible.”

Dr David Schroeder from the University of Reading, UK, who co-led the implementation of the melt pond scheme in the climate model, says: “This shows just how important sea ice processes like melt ponds are in the Arctic, and why it is crucial that they are incorporated into climate models.”

The extent of the areas sea ice covers varies between summer and winter. If more solar energy is absorbed at the surface, and temperatures rise further, a cycle of warming and melting occurs during summer months.

When the ice forms, the ocean water beneath becomes saltier and denser than the surrounding ocean. Saltier water sinks and moves along the ocean bottom towards the equator, while warm water from mid-depths to the surface travels from the equator towards the poles.

Scientists refer to this process as the ocean’s global “conveyor-belt”. Changes to the volume of sea ice can disrupt normal ocean circulation, with consequences for global climate. − Climate News Network

How soon will the northern polar ocean be ice-free? New research expects the end of Arctic sea ice by 2035.

LONDON, 11 August, 2020 − The temperature of the Arctic matters to the entire world: it helps to keep the global climate fairly cool. Scientists now say that by 2035 there could be an end to Arctic sea ice.

The northern polar ocean’s sea ice is a crucial element in the Earth system: because it is highly reflective, it sends solar radiation back out into space. Once it’s melted, there’s no longer any protection for the darker water and rock beneath, and nothing to prevent them absorbing the incoming heat.

High temperatures in the Arctic during the last interglacial – the warm period around 127,000 years ago – have puzzled scientists for decades.

Now the UK Met Office’s Hadley Centre climate model has enabled an international research team to compare Arctic sea ice conditions during the last interglacial with the present day. Their findings are important for improving predictions of future sea ice change.

What is striking about the latest research is the date it suggests for a possible total melt − 2035. Many studies have thought a mid-century crisis likely, with another even carefully specifying 2044 as the year to watch. So a breathing space of only 15 years may surprise some experts.

“The prospect of loss of sea ice by 2035 should really be focussing all our minds on achieving a low-carbon world as soon as humanly feasible”

During spring and early summer shallow pools of water form on the surface of the Arctic sea ice. These “melt ponds” help to determine how much sunlight is absorbed by the ice and how much is reflected back into space. The new Hadley Centre model is the UK’s most advanced physical representation of the Earth’s climate and a critical tool for climate research, and it incorporates sea ice and melt ponds.

The researchers report their findings in the journal Nature Climate Change. Using the model to look at Arctic sea ice during the last interglacial, they concluded that the impact of intense springtime sunshine created many melt ponds, which played a crucial role in sea ice melt. A simulation of the future using the same model indicates that the Arctic may become sea ice-free by 2035.

The joint lead author of the team is Dr Maria Vittoria Guarino, an earth system modeller at the British Antarctic Survey (BAS) in Cambridge. She says: “High temperatures in the Arctic have puzzled scientists for decades. Unravelling this mystery was technically and scientifically challenging. For the first time, we can begin to see how the Arctic became sea ice-free during the last interglacial.

“The advances made in climate modelling mean that we can create a more accurate simulation of the Earth’s past climate which, in turn, gives us greater confidence in model predictions for the future.”

Dr Louise Sime, the group head of the palaeoclimate group and joint lead author at BAS, says: “We know the Arctic is undergoing significant changes as our planet warms. By understanding what happened during Earth’s last warm period we are in a better position to understand what will happen in the future.

Melt ponds crucial

“The prospect of loss of sea ice by 2035 should really be focussing all our minds on achieving a low-carbon world as soon as humanly feasible.”

Dr David Schroeder from the University of Reading, UK, who co-led the implementation of the melt pond scheme in the climate model, says: “This shows just how important sea ice processes like melt ponds are in the Arctic, and why it is crucial that they are incorporated into climate models.”

The extent of the areas sea ice covers varies between summer and winter. If more solar energy is absorbed at the surface, and temperatures rise further, a cycle of warming and melting occurs during summer months.

When the ice forms, the ocean water beneath becomes saltier and denser than the surrounding ocean. Saltier water sinks and moves along the ocean bottom towards the equator, while warm water from mid-depths to the surface travels from the equator towards the poles.

Scientists refer to this process as the ocean’s global “conveyor-belt”. Changes to the volume of sea ice can disrupt normal ocean circulation, with consequences for global climate. − Climate News Network

250 million coastal dwellers will face rising floods

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

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

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

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

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

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

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

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

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

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

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

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

Estimate too low?

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Estimate too low?

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

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

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

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

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