Category Archives: Oceans

Ocean warming speeds vary with depth

The world’s oceans are a vast reservoir of heat, a slow register of natural climate change − and ocean warming speeds differ widely.

LONDON, 10 January, 2019 − Climate scientists who have found a new way to chart temperature change in the world’s seas over time say ocean warming speeds are much slower in deep water than on the surface.

Planet Earth is mostly ocean. Human-linked changes have started to raise global temperatures to what could be alarming levels and, as the thermometer rises, so will sea levels. So detailed understanding of temperature and ocean is vital. But two separate studies confirm that the connection is far from simple.

One study of the Atlantic confirms that in the last 150 years, the oceans have taken up 90% of the excess energy released by the combustion of fossil fuels to drive human economic growth and power − and to fuel potentially-catastrophic global warming and runaway climate change.

But what the oceans will actually do with that colossal burst of heat has yet to be fully explored. And a separate examination of the deep history of the Pacific Ocean confirms that change may be inexorable, but it is also very slow: the deeper parts of the Pacific are still registering the onset of the so-called “Little Ice Age” several centuries ago.

“These waters are so old and haven’t been near the surface in so long, they still ‘remember’ what was going on hundreds of years ago”

Both studies are reminders that oceanography is still a relatively new science and researchers still have a lot to learn about the fine detail of the ways in which temperature, atmosphere and ocean interact to affect climate over the world’s continents.

But repeated research has confirmed that the oceans are warming in response to human-triggered changes on land, that this warming presents several different kinds of hazard  to marine life, and that there is a link between overall ocean temperatures and the behaviour of the ocean’s currents, a link that plays out in dramatic shifts in regional climates.

So the rewards for a more precise understanding are considerable. But understanding starts with accurate and comprehensive data, and systematic measurement of ocean temperatures began only with the voyage of the British research ship HMS Challenger in 1871.

So Laure Zanna, a physicist at the University of Oxford and her colleagues, report in the Proceedings of the National Academy of Sciences that they deployed sophisticated mathematical techniques to calculate the heat uptake of the oceans and the way the blue planet has responded since 1871.

Huge heat uptake

Altogether, in the last 150 years, the deep waters have absorbed 436 zettajoules: a joule is the unit of energy required to deliver one watt for one second and a zettajoule is a number followed by 21 zeroes. This is an enormous amount of heat, roughly 1,000 times the energy consumed by 7 billion humans in the course of a year.

The researchers’ results so far show that roughly half the observed warming of the last 60 years – and the associated sea level rise – is linked to changes in ocean circulation. They were able to reconstruct two considerable bouts of warming, over the years 1920 to 1945 and between 1990 and 2015. What they have yet to do is sort out what this means for the behaviour of the oceans over the decades to come.

“The technique is only applicable to tracers like man-made carbon that are passively transported by ocean circulation,” Professor Zanna said. “However, heat does not behave in this manner as it affects circulation by changing the density of seawater. We were pleasantly surprised by how well the approach works. It opens up an exciting new way to study ocean warming in addition to using direct measurements.”

What the research also underlines is that the oceans have a long memory: so extensive and so deep are the five oceans that the surface waters may respond to 20th century greenhouse gas emissions while the deepest trenches contain water that last warmed more than 1,000 years ago in the reign of Charlemagne, the first Holy Roman Emperor.

Still adjusting

US oceanographers report in the journal Science that they matched predictions from computer models and modern data and ancient evidence with readings from the Challenger expedition to show that two kilometres under the waves, the Pacific Ocean is still adjusting to cooling that began with the onset of the Little Ice Age centuries ago.

Such studies count as basic research: as a way of testing techniques and establishing ground rules from which more discovery could follow. They also offer new ways to understand oceans as registers of climate change over long intervals.

“These waters are so old and haven’t been near the surface in so long, they still ‘remember’ what was going on hundreds of years ago when Europe experienced some of its coldest winters in history,” said Jake Gebbie, of the Woods Hole Oceanographic Institution.

“The close correspondence between prediction and observed trends gave us confidence that this is a real phenomenon.” − Climate News Network

The world’s oceans are a vast reservoir of heat, a slow register of natural climate change − and ocean warming speeds differ widely.

LONDON, 10 January, 2019 − Climate scientists who have found a new way to chart temperature change in the world’s seas over time say ocean warming speeds are much slower in deep water than on the surface.

Planet Earth is mostly ocean. Human-linked changes have started to raise global temperatures to what could be alarming levels and, as the thermometer rises, so will sea levels. So detailed understanding of temperature and ocean is vital. But two separate studies confirm that the connection is far from simple.

One study of the Atlantic confirms that in the last 150 years, the oceans have taken up 90% of the excess energy released by the combustion of fossil fuels to drive human economic growth and power − and to fuel potentially-catastrophic global warming and runaway climate change.

But what the oceans will actually do with that colossal burst of heat has yet to be fully explored. And a separate examination of the deep history of the Pacific Ocean confirms that change may be inexorable, but it is also very slow: the deeper parts of the Pacific are still registering the onset of the so-called “Little Ice Age” several centuries ago.

“These waters are so old and haven’t been near the surface in so long, they still ‘remember’ what was going on hundreds of years ago”

Both studies are reminders that oceanography is still a relatively new science and researchers still have a lot to learn about the fine detail of the ways in which temperature, atmosphere and ocean interact to affect climate over the world’s continents.

But repeated research has confirmed that the oceans are warming in response to human-triggered changes on land, that this warming presents several different kinds of hazard  to marine life, and that there is a link between overall ocean temperatures and the behaviour of the ocean’s currents, a link that plays out in dramatic shifts in regional climates.

So the rewards for a more precise understanding are considerable. But understanding starts with accurate and comprehensive data, and systematic measurement of ocean temperatures began only with the voyage of the British research ship HMS Challenger in 1871.

So Laure Zanna, a physicist at the University of Oxford and her colleagues, report in the Proceedings of the National Academy of Sciences that they deployed sophisticated mathematical techniques to calculate the heat uptake of the oceans and the way the blue planet has responded since 1871.

Huge heat uptake

Altogether, in the last 150 years, the deep waters have absorbed 436 zettajoules: a joule is the unit of energy required to deliver one watt for one second and a zettajoule is a number followed by 21 zeroes. This is an enormous amount of heat, roughly 1,000 times the energy consumed by 7 billion humans in the course of a year.

The researchers’ results so far show that roughly half the observed warming of the last 60 years – and the associated sea level rise – is linked to changes in ocean circulation. They were able to reconstruct two considerable bouts of warming, over the years 1920 to 1945 and between 1990 and 2015. What they have yet to do is sort out what this means for the behaviour of the oceans over the decades to come.

“The technique is only applicable to tracers like man-made carbon that are passively transported by ocean circulation,” Professor Zanna said. “However, heat does not behave in this manner as it affects circulation by changing the density of seawater. We were pleasantly surprised by how well the approach works. It opens up an exciting new way to study ocean warming in addition to using direct measurements.”

What the research also underlines is that the oceans have a long memory: so extensive and so deep are the five oceans that the surface waters may respond to 20th century greenhouse gas emissions while the deepest trenches contain water that last warmed more than 1,000 years ago in the reign of Charlemagne, the first Holy Roman Emperor.

Still adjusting

US oceanographers report in the journal Science that they matched predictions from computer models and modern data and ancient evidence with readings from the Challenger expedition to show that two kilometres under the waves, the Pacific Ocean is still adjusting to cooling that began with the onset of the Little Ice Age centuries ago.

Such studies count as basic research: as a way of testing techniques and establishing ground rules from which more discovery could follow. They also offer new ways to understand oceans as registers of climate change over long intervals.

“These waters are so old and haven’t been near the surface in so long, they still ‘remember’ what was going on hundreds of years ago when Europe experienced some of its coldest winters in history,” said Jake Gebbie, of the Woods Hole Oceanographic Institution.

“The close correspondence between prediction and observed trends gave us confidence that this is a real phenomenon.” − Climate News Network

Human horde leaves little room for nature

Our species’ planetary advance has been inexorable. The human horde means under a quarter of the world’s land surface now counts as wilderness.

LONDON, 8 November, 2018 – Only 23% of the planet’s habitable terrestrial surface now remains as undisturbed wilderness, thanks to the spread of the human horde.

A century ago, as the human population explosion began, 85% of the world was undisturbed living space for all the other species. Yet between 1993 and 2009 – in the years that followed hard on the first global summit to consider the state of the planetary environment – an aggregation of areas of wilderness larger than India was delivered over to human exploitation, scientists warn in the journal Nature.

“These results are nothing short of a horror story for the planet’s last wild places,” said James Watson, a scientist at the University of Queensland and with the Wildlife Conservation Society.

“The loss of wilderness must be treated in the same way we treat extinction. There is no reversing, once the first cut enters. The decision is forever.”

Ocean impact

Professor Watson and colleagues argued in August that humans had in some way poisoned, polluted, exploited or disturbed almost all the planet’s oceans: only 13% could now be classified as undisturbed.

Now he and others have addressed the state of the wild terrestrial soils and rocks. Take Antarctica – essentially uninhabited, and with no terrestrial wildlife – out of the equation, and the scale of planetary devastation becomes more stark: humans have now left their mark on 77% of the world’s living space.

And the remaining wilderness is unevenly distributed: just 20 nations hold or govern 94% of the remaining marine and terrestrial wilderness areas. Russia, Canada, Australia, the US and Brazil host 70% of these unspoiled spaces.

Professor Watson and many others have repeatedly argued that humankind continues to put the world’s wildlife at risk. A new study by the World Wide Fund for Nature highlights the scale of destruction, but repeated surveys by teams of researchers on all continents have pointed up the same danger.

The combination of human intrusion into the wilderness and the spectre of climate change is a disaster for the 10 million or so species, most of them as yet unidentified, with which humans share the planet.

“These results are nothing short of a horror story for the planet’s last wild places”

“A century ago, only 15% of the Earth’s surface was used by humans to grow crops and raise livestock,” Professor Watson said.

“Today, more than 77% of land – excluding Antarctica – and 87% of the ocean has been modified by the direct effects of human activities. It might be hard to believe, but between 1993 and 2009, an area of terrestrial wilderness larger than India – a staggering 3.3 million square kilometres – was lost to human settlement, farming, mining and other pressures.

“And in the ocean, the only regions that are free of industrial fishing, pollution and shipping are almost completely confined to the polar regions.” – Climate News Network

Our species’ planetary advance has been inexorable. The human horde means under a quarter of the world’s land surface now counts as wilderness.

LONDON, 8 November, 2018 – Only 23% of the planet’s habitable terrestrial surface now remains as undisturbed wilderness, thanks to the spread of the human horde.

A century ago, as the human population explosion began, 85% of the world was undisturbed living space for all the other species. Yet between 1993 and 2009 – in the years that followed hard on the first global summit to consider the state of the planetary environment – an aggregation of areas of wilderness larger than India was delivered over to human exploitation, scientists warn in the journal Nature.

“These results are nothing short of a horror story for the planet’s last wild places,” said James Watson, a scientist at the University of Queensland and with the Wildlife Conservation Society.

“The loss of wilderness must be treated in the same way we treat extinction. There is no reversing, once the first cut enters. The decision is forever.”

Ocean impact

Professor Watson and colleagues argued in August that humans had in some way poisoned, polluted, exploited or disturbed almost all the planet’s oceans: only 13% could now be classified as undisturbed.

Now he and others have addressed the state of the wild terrestrial soils and rocks. Take Antarctica – essentially uninhabited, and with no terrestrial wildlife – out of the equation, and the scale of planetary devastation becomes more stark: humans have now left their mark on 77% of the world’s living space.

And the remaining wilderness is unevenly distributed: just 20 nations hold or govern 94% of the remaining marine and terrestrial wilderness areas. Russia, Canada, Australia, the US and Brazil host 70% of these unspoiled spaces.

Professor Watson and many others have repeatedly argued that humankind continues to put the world’s wildlife at risk. A new study by the World Wide Fund for Nature highlights the scale of destruction, but repeated surveys by teams of researchers on all continents have pointed up the same danger.

The combination of human intrusion into the wilderness and the spectre of climate change is a disaster for the 10 million or so species, most of them as yet unidentified, with which humans share the planet.

“These results are nothing short of a horror story for the planet’s last wild places”

“A century ago, only 15% of the Earth’s surface was used by humans to grow crops and raise livestock,” Professor Watson said.

“Today, more than 77% of land – excluding Antarctica – and 87% of the ocean has been modified by the direct effects of human activities. It might be hard to believe, but between 1993 and 2009, an area of terrestrial wilderness larger than India – a staggering 3.3 million square kilometres – was lost to human settlement, farming, mining and other pressures.

“And in the ocean, the only regions that are free of industrial fishing, pollution and shipping are almost completely confined to the polar regions.” – Climate News Network

Ocean warming may be faster than thought

Science knows that ocean warming is occurring. A big challenge now is to work out how quickly the temperature is rising.

LONDON, 7 November, 2018 – The seas are getting hotter – and researchers have thought again about just how much faster ocean warming is happening. They believe that in the last 25 years the oceans have absorbed at least 60% more heat than previous global estimates by the UN’s Intergovernmental Panel on Climate Change (IPCC) had considered.

And they calculate this heat as the equivalent to 150 times the annual human electricity generation in any one year.

“Imagine if the ocean was only 30 feet (10m) deep,” said Laure Resplandy, a researcher at the Princeton Environment Institute in the US. “Our data show that it would have warmed by 6.5°C every decade since 1991. In comparison, the estimate of the last IPCC assessment report would correspond to a warming of only 4°C every decade.”

The oceans cover 70% of the Blue Planet, but take up about 90% of all the excess energy produced as the Earth warms. If scientists can put a precise figure to this energy, then they can make more precise guesses about the surface warming to come, as humans continue to burn fossil fuels, release greenhouse gases such as carbon dioxide into the atmosphere, and drive up the planetary thermometer.

“There will have to be an even more drastic shutdown of fossil fuel investment and an even faster switch to renewable sources of energy”

At the academic level, this is the search for a factor known to climate researchers as climate sensitivity: the way the world responds to ever-increasing ratios of greenhouse gas in the atmosphere.

At the human level, this plays out as ever-greater extremes of heat, drought and rainfall, with ever-higher risks of catastrophic storm or flood, or harvest failure, and ever-higher tallies of human suffering.

Comprehensive global measurements of ocean temperature date only from 2007 and the network of robot sensors that deliver continuous data about the top half of the ocean basins.

Dr Resplandy and her colleagues report in the journal Nature that they used a sophisticated approach based on very high-precision measurements of levels of oxygen and carbon dioxide in the air.

Gases released

Both gases are soluble, and the oceans are becoming more acidic as the seas absorb ever-greater levels of carbon dioxide. But as seas warm, they also become less able to hold their dissolved gases, and release them into the atmosphere.

This simple consequence of atmospheric physics meant that the researchers could use what they call “atmospheric potential oxygen” to arrive at a new way of measuring the heat the oceans must have absorbed over time.

They used the standard unit of energy: the joule. Their new budget for heat absorbed each year between 1991 and 2016 is 13 zettajoules. That is a digit followed by 21 zeroes, the kind of magnitude astronomers tend to use.

That the oceans are warming is no surprise: this has been obvious from the crudest comparison of old naval data with modern surface checks, and for years some researchers argued that ever-higher ocean temperatures could account for the so-called slowdown in global warming in the first dozen years of this century.

Challenging achievement

The new finding counts first as an academic achievement: there is now a more precise thermometer reading, and new calculations can begin.

One of the researchers, Ralph Keeling of the Scripps Institution of Oceanography, said: “The result significantly increases the confidence we can place in estimates of ocean warming and therefore help reduce uncertainty in the climate sensitivity, particularly closing off the possibility of very low climate sensitivity.”

But the result also suggests that internationally agreed attempts to hold planetary warming to a maximum of just 2°C – and the world has already warmed by around 1°C in the last century – become more challenging.

It means that there will have to be an even more drastic shutdown of fossil fuel investment and an even faster switch to renewable sources of energy such as sun and wind power. – Climate News Network

Science knows that ocean warming is occurring. A big challenge now is to work out how quickly the temperature is rising.

LONDON, 7 November, 2018 – The seas are getting hotter – and researchers have thought again about just how much faster ocean warming is happening. They believe that in the last 25 years the oceans have absorbed at least 60% more heat than previous global estimates by the UN’s Intergovernmental Panel on Climate Change (IPCC) had considered.

And they calculate this heat as the equivalent to 150 times the annual human electricity generation in any one year.

“Imagine if the ocean was only 30 feet (10m) deep,” said Laure Resplandy, a researcher at the Princeton Environment Institute in the US. “Our data show that it would have warmed by 6.5°C every decade since 1991. In comparison, the estimate of the last IPCC assessment report would correspond to a warming of only 4°C every decade.”

The oceans cover 70% of the Blue Planet, but take up about 90% of all the excess energy produced as the Earth warms. If scientists can put a precise figure to this energy, then they can make more precise guesses about the surface warming to come, as humans continue to burn fossil fuels, release greenhouse gases such as carbon dioxide into the atmosphere, and drive up the planetary thermometer.

“There will have to be an even more drastic shutdown of fossil fuel investment and an even faster switch to renewable sources of energy”

At the academic level, this is the search for a factor known to climate researchers as climate sensitivity: the way the world responds to ever-increasing ratios of greenhouse gas in the atmosphere.

At the human level, this plays out as ever-greater extremes of heat, drought and rainfall, with ever-higher risks of catastrophic storm or flood, or harvest failure, and ever-higher tallies of human suffering.

Comprehensive global measurements of ocean temperature date only from 2007 and the network of robot sensors that deliver continuous data about the top half of the ocean basins.

Dr Resplandy and her colleagues report in the journal Nature that they used a sophisticated approach based on very high-precision measurements of levels of oxygen and carbon dioxide in the air.

Gases released

Both gases are soluble, and the oceans are becoming more acidic as the seas absorb ever-greater levels of carbon dioxide. But as seas warm, they also become less able to hold their dissolved gases, and release them into the atmosphere.

This simple consequence of atmospheric physics meant that the researchers could use what they call “atmospheric potential oxygen” to arrive at a new way of measuring the heat the oceans must have absorbed over time.

They used the standard unit of energy: the joule. Their new budget for heat absorbed each year between 1991 and 2016 is 13 zettajoules. That is a digit followed by 21 zeroes, the kind of magnitude astronomers tend to use.

That the oceans are warming is no surprise: this has been obvious from the crudest comparison of old naval data with modern surface checks, and for years some researchers argued that ever-higher ocean temperatures could account for the so-called slowdown in global warming in the first dozen years of this century.

Challenging achievement

The new finding counts first as an academic achievement: there is now a more precise thermometer reading, and new calculations can begin.

One of the researchers, Ralph Keeling of the Scripps Institution of Oceanography, said: “The result significantly increases the confidence we can place in estimates of ocean warming and therefore help reduce uncertainty in the climate sensitivity, particularly closing off the possibility of very low climate sensitivity.”

But the result also suggests that internationally agreed attempts to hold planetary warming to a maximum of just 2°C – and the world has already warmed by around 1°C in the last century – become more challenging.

It means that there will have to be an even more drastic shutdown of fossil fuel investment and an even faster switch to renewable sources of energy such as sun and wind power. – Climate News Network

How Bangladesh can tackle rising seas

Salt levels in the coastal soils of Bangladesh will grow with the rising seas, putting two-fifths of its farmland at risk. Can farmers stay put?

LONDON, 29 October, 2018 − By 2140, rising seas are likely to be inundating the coastal lands (that are right now home to 1.3 billion people worldwide) in Bangladesh. Much of it is a vast estuarine silt bed fed by one of the world’s great river systems; the country is among those most vulnerable to sea level rise.

But, says a new study, many of the nation’s 165 million inhabitants may not be forced to become climate refugees.

As salty water seeps into the fertile muds and sands of the estuary of the Ganges-Brahmaputra river system, farmers could lose up to a fifth of their crop revenue each year.

An estimated 200,000 farmers may have to move inland. But the lucky ones with money to make the change may compensate by switching from rice cultivation to aquaculture, according to a new socio-economic study in the journal Nature Climate Change.

“The most vulnerable people will be the least resilient in the face of climate change, because they have limited resources to adapt”

“Unfortunately, this is likely to be most challenging for those farming families who have the fewest resources to begin with”, said Joyce Chen of the University of Ohio.

“My concern is that the most vulnerable people will be the least resilient in the face of climate change, because they have limited resources to adapt their farming practices or move longer distances in search of other employment.”

Bangladesh was once, notoriously, dismissed as a “basket case” by the US statesman Henry Kissinger. The low-lying terrain has always been vulnerable to the sea: in 1970, a storm surge propelled by a cyclone drove 10 metres of water over its lowlands, claiming an estimated 500,000 lives. In 1991, a six metre-high storm surge killed 138,000 and destroyed 10 million homes.

Global threat

Melting ice caps and expanding oceans threaten coasts everywhere: an estimated 13 million US citizens could be driven from their homes to count as climate refugees. But the spectre of sea level rise driven by profligate human combustion of fossil fuels puts Bangladesh in the front line of the challenge of climate change.

Dr Chen and a research colleague assembled as much data as they could about populations, incomes, soil geography and changing climate to try to guess what rising sea levels and ever-higher soil salinity will do to the nation over the next 120 years. Their calculations found 40% of the country’s croplands at risk, with coastal residents already experiencing frequent flooding.

But many of these had found ways to adapt: rice might not flourish in saline soil, but those who had made the big switch from crops to shrimp and fish farms had actually created more employment.

Accordingly, Dr Chen and her fellow researcher report that internal migration is likely to increase by at least 25%, as many are displaced by rising tides. But migration to other countries could actually fall by 66% because the supply of new work in labour-intensive fish farms could keep the locals at home.

Persistent risk

The coastal landscape will remain vulnerable to potentially devastating cyclones and storm surges, and this will be made worse by soil subsidence of from 10 to 18 mm a year.

Dr Chen sees her research as a test case for adaptation to climate change: other nations should take note. “The Bangladesh study offers interesting insights for governments of countries facing similar imminent threats of sea level rise,” she said.

“As internal migration patterns are expected to shift in countries vulnerable to sea level rise, ministries of planning may benefit from developing economic strategies that integrate and even leverage the expected additional number of workers coming from vulnerable areas.”

But, she warns, climate change will continue to create climate migrants. “Additional financial support from the international community may be necessary to foster resettlement programmes.” − Climate News Network

Salt levels in the coastal soils of Bangladesh will grow with the rising seas, putting two-fifths of its farmland at risk. Can farmers stay put?

LONDON, 29 October, 2018 − By 2140, rising seas are likely to be inundating the coastal lands (that are right now home to 1.3 billion people worldwide) in Bangladesh. Much of it is a vast estuarine silt bed fed by one of the world’s great river systems; the country is among those most vulnerable to sea level rise.

But, says a new study, many of the nation’s 165 million inhabitants may not be forced to become climate refugees.

As salty water seeps into the fertile muds and sands of the estuary of the Ganges-Brahmaputra river system, farmers could lose up to a fifth of their crop revenue each year.

An estimated 200,000 farmers may have to move inland. But the lucky ones with money to make the change may compensate by switching from rice cultivation to aquaculture, according to a new socio-economic study in the journal Nature Climate Change.

“The most vulnerable people will be the least resilient in the face of climate change, because they have limited resources to adapt”

“Unfortunately, this is likely to be most challenging for those farming families who have the fewest resources to begin with”, said Joyce Chen of the University of Ohio.

“My concern is that the most vulnerable people will be the least resilient in the face of climate change, because they have limited resources to adapt their farming practices or move longer distances in search of other employment.”

Bangladesh was once, notoriously, dismissed as a “basket case” by the US statesman Henry Kissinger. The low-lying terrain has always been vulnerable to the sea: in 1970, a storm surge propelled by a cyclone drove 10 metres of water over its lowlands, claiming an estimated 500,000 lives. In 1991, a six metre-high storm surge killed 138,000 and destroyed 10 million homes.

Global threat

Melting ice caps and expanding oceans threaten coasts everywhere: an estimated 13 million US citizens could be driven from their homes to count as climate refugees. But the spectre of sea level rise driven by profligate human combustion of fossil fuels puts Bangladesh in the front line of the challenge of climate change.

Dr Chen and a research colleague assembled as much data as they could about populations, incomes, soil geography and changing climate to try to guess what rising sea levels and ever-higher soil salinity will do to the nation over the next 120 years. Their calculations found 40% of the country’s croplands at risk, with coastal residents already experiencing frequent flooding.

But many of these had found ways to adapt: rice might not flourish in saline soil, but those who had made the big switch from crops to shrimp and fish farms had actually created more employment.

Accordingly, Dr Chen and her fellow researcher report that internal migration is likely to increase by at least 25%, as many are displaced by rising tides. But migration to other countries could actually fall by 66% because the supply of new work in labour-intensive fish farms could keep the locals at home.

Persistent risk

The coastal landscape will remain vulnerable to potentially devastating cyclones and storm surges, and this will be made worse by soil subsidence of from 10 to 18 mm a year.

Dr Chen sees her research as a test case for adaptation to climate change: other nations should take note. “The Bangladesh study offers interesting insights for governments of countries facing similar imminent threats of sea level rise,” she said.

“As internal migration patterns are expected to shift in countries vulnerable to sea level rise, ministries of planning may benefit from developing economic strategies that integrate and even leverage the expected additional number of workers coming from vulnerable areas.”

But, she warns, climate change will continue to create climate migrants. “Additional financial support from the international community may be necessary to foster resettlement programmes.” − Climate News Network

Climate change causes Canada’s oxygen loss

Scientists say climate change is causing oxygen loss in the cold waters of eastern Canada, imperilling the Greenland halibut and the Atlantic cod.

LONDON, 24 September, 2018 – Oceanographers have identified an act of slow suffocation, as oxygen loss grows near one of the world’s richest fishing grounds, and are linking the change to human-triggered global warming.

They have measured a dramatic drop in levels of dissolved oxygen deep in the Gulf of St Lawrence, in eastern Canada, and they link this increasing strangulation to shifts – connected to climate change driven by ever higher ratios of carbon dioxide in the atmosphere, as a consequence of the profligate burning of coal, oil and natural gas – in the Gulf Stream and the Labrador Current.

As carbon dioxide and other greenhouse gas levels have risen in the past 100 years, the Gulf Stream has shifted northward, and the Labrador Current has weakened. As a consequence, according to new research in Nature Climate Change, more warm, salty and oxygen-depleted water from the Gulf Stream is getting into one of the world’s great waterways.

Lower oxygen levels have already affected the Atlantic wolffish, the researchers say. And the change is a threat to the Atlantic cod, and the Greenland halibut: two of the world’s most prized commercial catches.

“The oxygen decline in this region was already reported, but what was not explored before was the underlying cause”

“Observations in the very inner Gulf of St Lawrence show a dramatic oxygen decline, which is reaching hypoxic conditions, meaning it can’t fully support marine life,” said Mariona Claret, of the University of Washington, who led the study.

“The oxygen decline in this region was already reported, but what was not explored before was the underlying cause.”

Researchers have warned for years that warmer waters mean lower levels of dissolved oxygen, and therefore ever greater risk of “dead zones” in the world’s oceans. There has been evidence that rates of oxygen depletion are higher than expected and direct evidence that fish may be voting with their fins, by migrating northwards as the oceans heat up.

Canadian fishery authorities have been measuring the salinity and temperature in the St Lawrence seaway since 1920, and oxygen levels since 1960. The latest study finds that the changes there have been more than twice the average change of 2% measured for the Atlantic and the oceans as a whole.

Current falters

An intricate, detailed computer simulation of the gulf and the seaway shows that the Labrador Current, which brings cold, oxygen-rich water southwards, has faltered, and the Gulf Stream – already warm and less oxygenated – has gained in ground.

The study also links shifts off coastal Canada to the bigger picture of an alarming decline in a marine monster called the Atlantic Meridional Overturning Circulation, which plays a powerful role in the climate of the North Atlantic.

The scientists speculate – their word – on the possibility that the lower oxygen levels in one watery corner of Canada “may ultimately influence the oxygen variability of the open North Atlantic.”

More alarmingly, they warn that their computer simulation may be delivering a very conservative picture, and that future oxygen declines in the Gulf may be “significantly larger.” – Climate News Network

Scientists say climate change is causing oxygen loss in the cold waters of eastern Canada, imperilling the Greenland halibut and the Atlantic cod.

LONDON, 24 September, 2018 – Oceanographers have identified an act of slow suffocation, as oxygen loss grows near one of the world’s richest fishing grounds, and are linking the change to human-triggered global warming.

They have measured a dramatic drop in levels of dissolved oxygen deep in the Gulf of St Lawrence, in eastern Canada, and they link this increasing strangulation to shifts – connected to climate change driven by ever higher ratios of carbon dioxide in the atmosphere, as a consequence of the profligate burning of coal, oil and natural gas – in the Gulf Stream and the Labrador Current.

As carbon dioxide and other greenhouse gas levels have risen in the past 100 years, the Gulf Stream has shifted northward, and the Labrador Current has weakened. As a consequence, according to new research in Nature Climate Change, more warm, salty and oxygen-depleted water from the Gulf Stream is getting into one of the world’s great waterways.

Lower oxygen levels have already affected the Atlantic wolffish, the researchers say. And the change is a threat to the Atlantic cod, and the Greenland halibut: two of the world’s most prized commercial catches.

“The oxygen decline in this region was already reported, but what was not explored before was the underlying cause”

“Observations in the very inner Gulf of St Lawrence show a dramatic oxygen decline, which is reaching hypoxic conditions, meaning it can’t fully support marine life,” said Mariona Claret, of the University of Washington, who led the study.

“The oxygen decline in this region was already reported, but what was not explored before was the underlying cause.”

Researchers have warned for years that warmer waters mean lower levels of dissolved oxygen, and therefore ever greater risk of “dead zones” in the world’s oceans. There has been evidence that rates of oxygen depletion are higher than expected and direct evidence that fish may be voting with their fins, by migrating northwards as the oceans heat up.

Canadian fishery authorities have been measuring the salinity and temperature in the St Lawrence seaway since 1920, and oxygen levels since 1960. The latest study finds that the changes there have been more than twice the average change of 2% measured for the Atlantic and the oceans as a whole.

Current falters

An intricate, detailed computer simulation of the gulf and the seaway shows that the Labrador Current, which brings cold, oxygen-rich water southwards, has faltered, and the Gulf Stream – already warm and less oxygenated – has gained in ground.

The study also links shifts off coastal Canada to the bigger picture of an alarming decline in a marine monster called the Atlantic Meridional Overturning Circulation, which plays a powerful role in the climate of the North Atlantic.

The scientists speculate – their word – on the possibility that the lower oxygen levels in one watery corner of Canada “may ultimately influence the oxygen variability of the open North Atlantic.”

More alarmingly, they warn that their computer simulation may be delivering a very conservative picture, and that future oxygen declines in the Gulf may be “significantly larger.” – Climate News Network

Tax havens threaten oceans and rainforests

Most of the foreign money funding ocean plunder and the felling of the Amazon forest comes through tax havens, researchers say.

LONDON, 14 August, 2018 – Tax havens have provided more than two-thirds of the foreign capital known to be linked to Amazon deforestation and pirate fishing, a new study says.

The researchers say 70% of known vessels involved in illegal, unreported and unregulated (IUU) fishing are or have been flagged under a tax haven jurisdiction. On average, they report, 68% of all investigated foreign capital (US$18.4bn of a total $26.9bn) which went to sectors associated with Amazon  deforestation between 2000 and 2011 was transferred through tax havens.

The report is the work of a team of researchers from the Stockholm Resilience Centre (SRC) and the Global Economic Dynamics and the Biosphere programme (GEDB), who say it is the first study to show how tax havens are linked to economic sectors with the potential to cause serious global environmental damage.

They say the release of the Paradise Papers and Panama Papers exposed how multinationals, politicians and the rich use offshore tax havens to conceal their wealth and money flows, and to reduce their exposure to tax. Accepting that the term “tax haven” is contested, their report uses a definition proposed in a report prepared for the US Congress.

The study’s lead author, Victor Galaz, deputy director of the SRC, says: “Our analysis shows that the use of tax havens is not only a socio-political and economic challenge, but also an environmental one. While the use of tax haven jurisdictions is not illegal in itself, financial secrecy hampers the ability to analyse how financial flows affect economic activities on the ground, and their environmental impacts.”

The study, published in the journal Nature Ecology and Evolution, is part of an on-going research project, Earth System Finance: New perspectives on financial markets and sustainability, led by GEDB and the Stockholm Resilience Centre in collaboration with Future Earth.

Systematic approach

The researchers say most previous analyses of the environmental impacts of tax havens are the work of investigative journalists focusing on a few locations. The new study, in contrast, takes a more systematic approach to analyse how the havens influence the sustainability of the ocean and the Amazon rainforest, two examples of the global environmental commons.

The Amazon forest is critical for stabilising the Earth’s climate system, and the oceans provide protein and income for millions of people worldwide, particularly in low-income food-deficit countries.

“The absence of a more systemic view is not surprising considering the chronic lack of data resulting from the financial opaqueness created by the use of these jurisdictions,” says co-author Beatrice Crona, GEDB’s executive director.

The study says lack of transparency hides how tax havens are linked to the degradation of environmental commons that are crucial for both people and planet at global scales.

“The use of tax havens is not only a socio-political and economic challenge, but also an environmental one”

It includes the first calculation of the foreign capital that flows into the beef and soya sectors operating in the Brazilian Amazon, both linked to deforestation.

The Cayman Islands proved to be the largest governmental source of transfers for foreign capital to both sectors. Well-known as a tax haven, the Islands provide three benefits to investors: legal efficiency, tax minimisation, and secrecy.

The study also includes a systematic analysis of tax havens’ role in global IUU fishing. With 70% of the vessels found to carry out or support IUU fishing, and for which flag information is available, flagged under a tax haven jurisdiction now or in the past, Belize and Panama are frequently mentioned.

Many of these tax havens are also so-called flags of convenience states, countries with limited monitoring and enforcement capacity that do not penalise vessels sailing under their flag even if they are identified as operating in violation of international law.

Dual identities

This combination of tax havens and flags of convenience allows companies to operate fishing vessels with dual identities, one used for legal and the other for illegal fishing.

“The global nature of fisheries value chains, complex ownership structures and limited governance capacities of many coastal nations, make the sector susceptible to the use of tax havens,” says co-author Henrik Österblom, SRC  deputy science director.

Among issues which the researchers suggest should be central to future research and to the governance of tax havens is the loss of tax revenue the havens cause. This, they argue, should be seen as an indirect subsidy to economic activities which damage the global commons, and organisations like UN Environment should assess the environmental costs involved.

And they argue that the international community should view tax evasion and aggressive tax planning as not only a socio-political problem, but also an environmental one. Putting tax havens on the global sustainability agenda, they say, is key to protecting the environment and achieving the UN Sustainable Development Goals. – Climate News Network

Most of the foreign money funding ocean plunder and the felling of the Amazon forest comes through tax havens, researchers say.

LONDON, 14 August, 2018 – Tax havens have provided more than two-thirds of the foreign capital known to be linked to Amazon deforestation and pirate fishing, a new study says.

The researchers say 70% of known vessels involved in illegal, unreported and unregulated (IUU) fishing are or have been flagged under a tax haven jurisdiction. On average, they report, 68% of all investigated foreign capital (US$18.4bn of a total $26.9bn) which went to sectors associated with Amazon  deforestation between 2000 and 2011 was transferred through tax havens.

The report is the work of a team of researchers from the Stockholm Resilience Centre (SRC) and the Global Economic Dynamics and the Biosphere programme (GEDB), who say it is the first study to show how tax havens are linked to economic sectors with the potential to cause serious global environmental damage.

They say the release of the Paradise Papers and Panama Papers exposed how multinationals, politicians and the rich use offshore tax havens to conceal their wealth and money flows, and to reduce their exposure to tax. Accepting that the term “tax haven” is contested, their report uses a definition proposed in a report prepared for the US Congress.

The study’s lead author, Victor Galaz, deputy director of the SRC, says: “Our analysis shows that the use of tax havens is not only a socio-political and economic challenge, but also an environmental one. While the use of tax haven jurisdictions is not illegal in itself, financial secrecy hampers the ability to analyse how financial flows affect economic activities on the ground, and their environmental impacts.”

The study, published in the journal Nature Ecology and Evolution, is part of an on-going research project, Earth System Finance: New perspectives on financial markets and sustainability, led by GEDB and the Stockholm Resilience Centre in collaboration with Future Earth.

Systematic approach

The researchers say most previous analyses of the environmental impacts of tax havens are the work of investigative journalists focusing on a few locations. The new study, in contrast, takes a more systematic approach to analyse how the havens influence the sustainability of the ocean and the Amazon rainforest, two examples of the global environmental commons.

The Amazon forest is critical for stabilising the Earth’s climate system, and the oceans provide protein and income for millions of people worldwide, particularly in low-income food-deficit countries.

“The absence of a more systemic view is not surprising considering the chronic lack of data resulting from the financial opaqueness created by the use of these jurisdictions,” says co-author Beatrice Crona, GEDB’s executive director.

The study says lack of transparency hides how tax havens are linked to the degradation of environmental commons that are crucial for both people and planet at global scales.

“The use of tax havens is not only a socio-political and economic challenge, but also an environmental one”

It includes the first calculation of the foreign capital that flows into the beef and soya sectors operating in the Brazilian Amazon, both linked to deforestation.

The Cayman Islands proved to be the largest governmental source of transfers for foreign capital to both sectors. Well-known as a tax haven, the Islands provide three benefits to investors: legal efficiency, tax minimisation, and secrecy.

The study also includes a systematic analysis of tax havens’ role in global IUU fishing. With 70% of the vessels found to carry out or support IUU fishing, and for which flag information is available, flagged under a tax haven jurisdiction now or in the past, Belize and Panama are frequently mentioned.

Many of these tax havens are also so-called flags of convenience states, countries with limited monitoring and enforcement capacity that do not penalise vessels sailing under their flag even if they are identified as operating in violation of international law.

Dual identities

This combination of tax havens and flags of convenience allows companies to operate fishing vessels with dual identities, one used for legal and the other for illegal fishing.

“The global nature of fisheries value chains, complex ownership structures and limited governance capacities of many coastal nations, make the sector susceptible to the use of tax havens,” says co-author Henrik Österblom, SRC  deputy science director.

Among issues which the researchers suggest should be central to future research and to the governance of tax havens is the loss of tax revenue the havens cause. This, they argue, should be seen as an indirect subsidy to economic activities which damage the global commons, and organisations like UN Environment should assess the environmental costs involved.

And they argue that the international community should view tax evasion and aggressive tax planning as not only a socio-political problem, but also an environmental one. Putting tax havens on the global sustainability agenda, they say, is key to protecting the environment and achieving the UN Sustainable Development Goals. – Climate News Network

Human activity leaves diminished oceans

Humankind has already disturbed or degraded six-sevenths of the blue planet, with diminished oceans the result. And that is before the impact of climate change.

LONDON, 3 August, 2018 – Humans huddle on a small part of the Earth’s surface, but our activity on the rest will leave our descendants only diminished oceans. Thanks to us, the wilderness of the world’s wide seas has shrunk drastically.

Earth is a waterworld: 70% of it is swept by ocean. And 87% of this waterworld has been to some degree fouled, polluted, poisoned or impoverished by the actions of one almost entirely terrestrial mammal. That is, according to a new survey, only 13% of the high seas can now be considered true wilderness.

Terrestrial life is smeared thinly. It is concentrated almost entirely in an altitude bounded by tree roots and canopy. But all the ocean is habitable, from the tidal shallows to the abyssal plain. It is home to the greatest mountain chain on the planet and to the deepest chasms, and in all it makes up 99% of the living space on Earth.

Researchers who looked at 16 different kinds of watery realm and tested them for 15 different kinds of human impact – among them commercial shipping, sediment and fertiliser run-off, and overfishing – report in the journal Current Biology that humans had left their mark almost everywhere.

“We were astonished by just how little marine wilderness remains,” said Kendall Jones, a researcher at the University of Queensland in Australia, and also of the Wildlife Conservation Society.

Huge extent

“The ocean is immense, covering over 70% of our planet, but we’ve managed to significantly impact almost all of this vast ecosystem.”

The surviving watery wilderness is estimated at an area of 54 million square kilometres. Although this is seemingly an enormous tract – think of the land areas of Russia, China, Canada, the US and Australia rolled up together – it is still less than a seventh part of the sea surface.

Most of this “untouched” ocean is concentrated in the Arctic, the Antarctic, and around the more remote Pacific islands. Hardly any marine wilderness survives along the continental coastlines.

The study comes only weeks after a survey of land conservation areas – once again, led by researchers from the University of Queensland and the Wildlife Conservation Society – found that even those stretches of mountain, savannah, forest and wetland formally recognized by governments as nature reserves or conservation zones were in many cases significantly disturbed or degraded by human intrusion.

The plight of the high seas has been disturbing marine scientists and oceanographers for some time. They have repeatedly warned that human-driven climate change is affecting ocean temperatures and compromising the health of the ecosystems on which, for instance, commercial fisheries depend.

“Pristine wilderness areas hold massive levels of biodiversity and endemic species and are some of the last places on earth where big populations of apex predators are still found”

Human actions have created “dead zones” and great tracts of toxic algal growths fed by nutrients from the land. Plastic waste has been found almost everywhere, and changes in water chemistry threaten many species at all depths.

But the Queensland study looks only at those measurable human impacts that are not connected with climate change: the implicit message is that acidification, sea level rise, and ocean temperature increase, all of them driven by profligate human combustion of fossil fuels, will ultimately affect even those areas of ocean defined as surviving wilderness.

Research of this nature is inevitably a matter of meticulous accounting: scientists comb through huge numbers of studies, and identify the data on which they can rely, and then find ways to test their hypothesis. This involved, for instance, checking the range and distribution of more than 21,000 marine species, and separately considering submarine kelp forests, coastal reefs, warm and temperate zones, the deep ocean and the polar waters.

Little protection

The researchers found that more than 8% of the wilderness was in the warm Indo-Pacific and that only 5% of the remaining marine wilderness enjoyed any formal governmental or international protection.

“Pristine wilderness areas hold massive levels of biodiversity and endemic species and are some of the last places on earth where big populations of apex predators are still found,” Kendall Jones said.

“This means the vast majority of marine wilderness could be lost at any time, as improvements in technology allow us to fish deeper and ship farther than ever before.

“Thanks to a warming climate, even some places that were once safe due to year-round ice cover can now be fished.” – Climate News Network

Humankind has already disturbed or degraded six-sevenths of the blue planet, with diminished oceans the result. And that is before the impact of climate change.

LONDON, 3 August, 2018 – Humans huddle on a small part of the Earth’s surface, but our activity on the rest will leave our descendants only diminished oceans. Thanks to us, the wilderness of the world’s wide seas has shrunk drastically.

Earth is a waterworld: 70% of it is swept by ocean. And 87% of this waterworld has been to some degree fouled, polluted, poisoned or impoverished by the actions of one almost entirely terrestrial mammal. That is, according to a new survey, only 13% of the high seas can now be considered true wilderness.

Terrestrial life is smeared thinly. It is concentrated almost entirely in an altitude bounded by tree roots and canopy. But all the ocean is habitable, from the tidal shallows to the abyssal plain. It is home to the greatest mountain chain on the planet and to the deepest chasms, and in all it makes up 99% of the living space on Earth.

Researchers who looked at 16 different kinds of watery realm and tested them for 15 different kinds of human impact – among them commercial shipping, sediment and fertiliser run-off, and overfishing – report in the journal Current Biology that humans had left their mark almost everywhere.

“We were astonished by just how little marine wilderness remains,” said Kendall Jones, a researcher at the University of Queensland in Australia, and also of the Wildlife Conservation Society.

Huge extent

“The ocean is immense, covering over 70% of our planet, but we’ve managed to significantly impact almost all of this vast ecosystem.”

The surviving watery wilderness is estimated at an area of 54 million square kilometres. Although this is seemingly an enormous tract – think of the land areas of Russia, China, Canada, the US and Australia rolled up together – it is still less than a seventh part of the sea surface.

Most of this “untouched” ocean is concentrated in the Arctic, the Antarctic, and around the more remote Pacific islands. Hardly any marine wilderness survives along the continental coastlines.

The study comes only weeks after a survey of land conservation areas – once again, led by researchers from the University of Queensland and the Wildlife Conservation Society – found that even those stretches of mountain, savannah, forest and wetland formally recognized by governments as nature reserves or conservation zones were in many cases significantly disturbed or degraded by human intrusion.

The plight of the high seas has been disturbing marine scientists and oceanographers for some time. They have repeatedly warned that human-driven climate change is affecting ocean temperatures and compromising the health of the ecosystems on which, for instance, commercial fisheries depend.

“Pristine wilderness areas hold massive levels of biodiversity and endemic species and are some of the last places on earth where big populations of apex predators are still found”

Human actions have created “dead zones” and great tracts of toxic algal growths fed by nutrients from the land. Plastic waste has been found almost everywhere, and changes in water chemistry threaten many species at all depths.

But the Queensland study looks only at those measurable human impacts that are not connected with climate change: the implicit message is that acidification, sea level rise, and ocean temperature increase, all of them driven by profligate human combustion of fossil fuels, will ultimately affect even those areas of ocean defined as surviving wilderness.

Research of this nature is inevitably a matter of meticulous accounting: scientists comb through huge numbers of studies, and identify the data on which they can rely, and then find ways to test their hypothesis. This involved, for instance, checking the range and distribution of more than 21,000 marine species, and separately considering submarine kelp forests, coastal reefs, warm and temperate zones, the deep ocean and the polar waters.

Little protection

The researchers found that more than 8% of the wilderness was in the warm Indo-Pacific and that only 5% of the remaining marine wilderness enjoyed any formal governmental or international protection.

“Pristine wilderness areas hold massive levels of biodiversity and endemic species and are some of the last places on earth where big populations of apex predators are still found,” Kendall Jones said.

“This means the vast majority of marine wilderness could be lost at any time, as improvements in technology allow us to fish deeper and ship farther than ever before.

“Thanks to a warming climate, even some places that were once safe due to year-round ice cover can now be fished.” – Climate News Network

Fish can’t smell well in more acidic seas

If you can’t smell food, you’re in trouble, and it’s worse if you can’t scent danger. More acidic seas could affect fishes’ ability to smell.

LONDON, 23 July, 2018 – More acidic seas mean greater dangers for fish. Sea bass tested in oceans with the greater levels of dissolved carbon dioxide expected at the end of the century had their sense of smell dramatically reduced by the change.

Since fish depend on smell to forage for food, avoid predators, recognise each other and identify spawning grounds, the loss of smell could mean a more dangerous world.

British and Portuguese scientists report in the journal Nature Climate Change that they used a mix of physiological and behavioural studies to work out how a valuable commercial species – Dicentrarchus labrax, also known as the European bass or loup de mer – responded to higher levels of dissolved carbon dioxide (CO2) in ocean waters.

Oceanic CO2 has risen by 43% since the start of the Industrial Revolution, when humans began burning fossil fuels at ever-increasing rates, to discharge greenhouse gases into the atmosphere, and thus into the seas. By 2100, current levels of this dissolved gas will have more than doubled.

And the researchers found that to detect a scent, under end-of-century conditions, juvenile bass had to be 42% nearer the source.

“Having to cope with two different problems caused by CO2, rather than just one, may reduce their ability to adapt or how long this will take”

“First we compared the behaviour of juvenile sea bass at CO2 levels typical of today’s ocean conditions, and those predicted for the end of the century,” said Cosima Porteous of the University of Exeter, UK, who led the research.

“Sea bass in acidic waters swam less and were less likely to respond when they encountered the smell of a predator. These fish were also more likely to ‘freeze’, indicating anxiety.”

The study confirms that economically important species will be affected by changes in ocean water chemistry: as waters warm, fish can migrate to cooler climates, but the impact of acidification will be much the same across the entire planet.

Researchers warned years ago that shifts in what chemists call the pH value of the oceans could seriously affect the citizens of the deep. Carbon dioxide has been implicated in at least one long-ago distant mass extinction event. Increasing acidification threatens corals and other species that employ carbonates. It has been found to alter behaviour or present a hazard to sharks, submarine snails and shrimps, and other species such as sea urchins and rockfish.

Commercial significance

The new study is hailed as the first to test the olfactory responses of a commercially important species. Although only sea bass were tested, mechanisms of smell in fish are thought to be the same across a wide range of species.

“Their ability to detect and respond to some odours associated with food and threatening situations was more strongly affected than for other odours. We think this is explained by acidified water affecting how odorant molecules bind to olfactory receptors in the fish’s nose, reducing how well they can distinguish these important stimuli,” said Dr Porteous.

And her colleague, Rod Wilson from Exeter, said: “Our intriguing results show that CO2 impacts the nose of the fish directly. This will be in addition to the impact of CO2 on their central nervous system function suggested by others previously, which proposed an impaired processing of information in the brain itself.

“It is not yet known how rapidly fish will be able to overcome these problems as CO2 rises in the future. However, having to cope with two different problems caused by CO2, rather than just one, may reduce their ability to adapt or how long this will take.” – Climate News Network

If you can’t smell food, you’re in trouble, and it’s worse if you can’t scent danger. More acidic seas could affect fishes’ ability to smell.

LONDON, 23 July, 2018 – More acidic seas mean greater dangers for fish. Sea bass tested in oceans with the greater levels of dissolved carbon dioxide expected at the end of the century had their sense of smell dramatically reduced by the change.

Since fish depend on smell to forage for food, avoid predators, recognise each other and identify spawning grounds, the loss of smell could mean a more dangerous world.

British and Portuguese scientists report in the journal Nature Climate Change that they used a mix of physiological and behavioural studies to work out how a valuable commercial species – Dicentrarchus labrax, also known as the European bass or loup de mer – responded to higher levels of dissolved carbon dioxide (CO2) in ocean waters.

Oceanic CO2 has risen by 43% since the start of the Industrial Revolution, when humans began burning fossil fuels at ever-increasing rates, to discharge greenhouse gases into the atmosphere, and thus into the seas. By 2100, current levels of this dissolved gas will have more than doubled.

And the researchers found that to detect a scent, under end-of-century conditions, juvenile bass had to be 42% nearer the source.

“Having to cope with two different problems caused by CO2, rather than just one, may reduce their ability to adapt or how long this will take”

“First we compared the behaviour of juvenile sea bass at CO2 levels typical of today’s ocean conditions, and those predicted for the end of the century,” said Cosima Porteous of the University of Exeter, UK, who led the research.

“Sea bass in acidic waters swam less and were less likely to respond when they encountered the smell of a predator. These fish were also more likely to ‘freeze’, indicating anxiety.”

The study confirms that economically important species will be affected by changes in ocean water chemistry: as waters warm, fish can migrate to cooler climates, but the impact of acidification will be much the same across the entire planet.

Researchers warned years ago that shifts in what chemists call the pH value of the oceans could seriously affect the citizens of the deep. Carbon dioxide has been implicated in at least one long-ago distant mass extinction event. Increasing acidification threatens corals and other species that employ carbonates. It has been found to alter behaviour or present a hazard to sharks, submarine snails and shrimps, and other species such as sea urchins and rockfish.

Commercial significance

The new study is hailed as the first to test the olfactory responses of a commercially important species. Although only sea bass were tested, mechanisms of smell in fish are thought to be the same across a wide range of species.

“Their ability to detect and respond to some odours associated with food and threatening situations was more strongly affected than for other odours. We think this is explained by acidified water affecting how odorant molecules bind to olfactory receptors in the fish’s nose, reducing how well they can distinguish these important stimuli,” said Dr Porteous.

And her colleague, Rod Wilson from Exeter, said: “Our intriguing results show that CO2 impacts the nose of the fish directly. This will be in addition to the impact of CO2 on their central nervous system function suggested by others previously, which proposed an impaired processing of information in the brain itself.

“It is not yet known how rapidly fish will be able to overcome these problems as CO2 rises in the future. However, having to cope with two different problems caused by CO2, rather than just one, may reduce their ability to adapt or how long this will take.” – Climate News Network

Nature may explain North Atlantic circulation

Ocean circulation distributes the planet’s heat. If the North Atlantic circulation slows, is it because of global warming, or a natural cycle?

LONDON, 26 July, 2018 – The world can breathe again. Europe can relax: the glaciers will not return. The North Atlantic circulation may resume its former pace and the Gulf Stream slowdown could be coming to an end.

But that may not be entirely good news. Global warming could also be about to accelerate, according to new research into one of oceanography’s most enigmatic phenomena, the North Atlantic Meridional Overturning Circulation.

New studies of all the data so far by an ocean scientist and a mathematician say that what affects North Atlantic circulation may not be driven by man-made climate change. The ocean may be responding to a very long-term natural climate cycle.

At the heart of the puzzle is a simple fact. The flow of warm water from the tropical Atlantic right up to the coast of northern Norway has a dramatic impact on western Europe’s climate. This means that the United Kingdom, France, and other nations are conspicuously warmer than they might be if latitude was the only factor.

“We do not know if it is periodic, but based on the surface phenomena we think it’s very likely it is episodic”

A former UK chief scientist once calculated that the Gulf Stream contributed 27,000 times the warmth generated by all the UK’s power stations. But theorists argued that as the Arctic region warmed, the rate of flow could diminish, and paradoxically throw Europe into a new little Ice Age. A 2004 Hollywood disaster movie called The Day After Tomorrow followed this logic, with Britain frozen and glaciers cascading south into the US.

In fact, no such calamitous and sudden return of the intense and lethal cold could happen, but researchers have since then consistently observed a pattern of slowing in the North Atlantic circulation, linked such slowdowns to global warming
driven by profligate use of fossil fuels that enrich the levels of greenhouse gases in the atmosphere, and repeatedly warned that the consequences could be costly or even devastating.

But a new study of the data available exposes other possibilities. In the first place, climate scientists have direct measurements of the circulation strength only from 2004, and the decline measured since then has been 10 times more than anyone expected. Perhaps the slowdown could be just part of a regular, rhythmic cycle that happens independently of anything humans have done to trigger global warming, researchers say in the journal Nature.

“Many have focused on the fact that it’s declining very rapidly, and that if the trend continues it will go past a tipping point, bringing a catastrophe such as an ice age,” said Ka-Kit Tung, a mathematician at the University of Washington in the US.

Already over

“It turns out that none of that is going to happen in the near future. The fast response may instead be part of a natural cycle and there are signs that the decline is already ending.”

The Atlantic Meridional Overturning Circulation takes warm surface water northward. The dense salty water sinks into the Labrador and Nordic Seas and returns at depth all the way to the Southern Ocean, to rise again. The puzzle is what happens next.

As the current sinks in the far north, it carries heat away from the surface. But the same transport of heat causes the northern glaciers to recede, and melt, diluting the saline water and making it less likely to sink. So the circulation slows.

The reasoning that follows is that, in a slow phase, the North Atlantic becomes cooler, the ice melt slows, the fresh meltwater sources begin to dry up and the heavier, saltier water plunges more urgently, and the whole circulation speeds up again.

Disagreement

And if this happens in a natural cycle – and not all climate scientists and oceanographers will agree – it is one that lasts for many decades: 60 to 70 years. But oceanographers don’t have the more than 60 to 70 years of measurements needed to confirm this pattern.

“We have about one cycle of observations at depth, so we do not know if it is periodic, but based on the surface phenomena we think it’s very likely it is episodic,” said Professor Tung.

“The good news is that the indicators show that this slowdown of the Atlantic overturning circulation is ending, and so we shouldn’t be alarmed that this current will collapse any time soon.

“The bad news is that surface temperatures are likely to start rising more quickly in the coming decades.” – Climate News Network

Ocean circulation distributes the planet’s heat. If the North Atlantic circulation slows, is it because of global warming, or a natural cycle?

LONDON, 26 July, 2018 – The world can breathe again. Europe can relax: the glaciers will not return. The North Atlantic circulation may resume its former pace and the Gulf Stream slowdown could be coming to an end.

But that may not be entirely good news. Global warming could also be about to accelerate, according to new research into one of oceanography’s most enigmatic phenomena, the North Atlantic Meridional Overturning Circulation.

New studies of all the data so far by an ocean scientist and a mathematician say that what affects North Atlantic circulation may not be driven by man-made climate change. The ocean may be responding to a very long-term natural climate cycle.

At the heart of the puzzle is a simple fact. The flow of warm water from the tropical Atlantic right up to the coast of northern Norway has a dramatic impact on western Europe’s climate. This means that the United Kingdom, France, and other nations are conspicuously warmer than they might be if latitude was the only factor.

“We do not know if it is periodic, but based on the surface phenomena we think it’s very likely it is episodic”

A former UK chief scientist once calculated that the Gulf Stream contributed 27,000 times the warmth generated by all the UK’s power stations. But theorists argued that as the Arctic region warmed, the rate of flow could diminish, and paradoxically throw Europe into a new little Ice Age. A 2004 Hollywood disaster movie called The Day After Tomorrow followed this logic, with Britain frozen and glaciers cascading south into the US.

In fact, no such calamitous and sudden return of the intense and lethal cold could happen, but researchers have since then consistently observed a pattern of slowing in the North Atlantic circulation, linked such slowdowns to global warming
driven by profligate use of fossil fuels that enrich the levels of greenhouse gases in the atmosphere, and repeatedly warned that the consequences could be costly or even devastating.

But a new study of the data available exposes other possibilities. In the first place, climate scientists have direct measurements of the circulation strength only from 2004, and the decline measured since then has been 10 times more than anyone expected. Perhaps the slowdown could be just part of a regular, rhythmic cycle that happens independently of anything humans have done to trigger global warming, researchers say in the journal Nature.

“Many have focused on the fact that it’s declining very rapidly, and that if the trend continues it will go past a tipping point, bringing a catastrophe such as an ice age,” said Ka-Kit Tung, a mathematician at the University of Washington in the US.

Already over

“It turns out that none of that is going to happen in the near future. The fast response may instead be part of a natural cycle and there are signs that the decline is already ending.”

The Atlantic Meridional Overturning Circulation takes warm surface water northward. The dense salty water sinks into the Labrador and Nordic Seas and returns at depth all the way to the Southern Ocean, to rise again. The puzzle is what happens next.

As the current sinks in the far north, it carries heat away from the surface. But the same transport of heat causes the northern glaciers to recede, and melt, diluting the saline water and making it less likely to sink. So the circulation slows.

The reasoning that follows is that, in a slow phase, the North Atlantic becomes cooler, the ice melt slows, the fresh meltwater sources begin to dry up and the heavier, saltier water plunges more urgently, and the whole circulation speeds up again.

Disagreement

And if this happens in a natural cycle – and not all climate scientists and oceanographers will agree – it is one that lasts for many decades: 60 to 70 years. But oceanographers don’t have the more than 60 to 70 years of measurements needed to confirm this pattern.

“We have about one cycle of observations at depth, so we do not know if it is periodic, but based on the surface phenomena we think it’s very likely it is episodic,” said Professor Tung.

“The good news is that the indicators show that this slowdown of the Atlantic overturning circulation is ending, and so we shouldn’t be alarmed that this current will collapse any time soon.

“The bad news is that surface temperatures are likely to start rising more quickly in the coming decades.” – Climate News Network

Alien seaweed arrives in Antarctica

For more than a century, scientists believed that only humans could cross the hostile oceans to reach Antarctica. Some strands of alien seaweed tell another story.

LONDON, 19 July, 2018 – A foreign invader, a species of alien seaweed, has managed to cross the oceans to reach the frozen Antarctic shores. So scientists may have to give up a cherished belief: that Antarctica is inviolate.

For a century, researchers have assumed that the mix of ocean currents, distance and temperature have kept the Great White Continent shielded from invasion by Pacific or Atlantic flotsam.

But the discovery of strands of kelp on an Antarctic beach – seaweed that may have drifted for considerable periods and a distance of 20,000 kms before becoming stranded far from home – brings an end to that belief. And the discovery suggests that global warming could bring serious changes to Antarctic ecosystems.

“Our findings also indicate that plants and animals living on Antarctica could be more vulnerable to climate change than we suspected”

“This finding shows us that living plants and animals can reach Antarctica across the ocean, with temperate and sub-Antarctic marine species probably bombarding Antarctic coastlines all the time,” said Ceridwen Fraser, of the Australian National University.

“We always thought Antarctic plants and animals were distinct because they were isolated, but this research now suggests these differences are almost entirely due to environmental extremes, not isolation.”

Dr Fraser and her colleagues report in the journal Nature Climate Change that strands of southern bull kelp, Durvillaea antarctica, found by a Chilean scientist, must have floated 20,000 km from the Kerguelen Islands and South Georgia. The kelp was encrusted with barnacles, evidence of a long time adrift.

In fact, researchers believe, it may be evidence of the longest episode of “biological rafting” ever confirmed. The word raft is significant: such floating platforms could provide shelter and transport for other biological invaders.

Plastic next?

Until now, the assumption has been that the pattern of surface currents and westerly winds tends to drive drifting material northwards from Antarctica. The discovery suggests that if kelp can get there, so can floating driftwood, or plastic debris, or any other unwelcome visitor.

The researchers think large waves driven by Southern Ocean storms may have steered the kelp rafts over what had been considered a natural ocean barrier. Global warming has begun to change conditions in Antarctica, and the continent – considered the last great tract of terrain unmarked by human colonisation – could become increasingly vulnerable to change.

“This is an unequivocal demonstration that marine species from the north can reach Antarctica. To get there the kelp had to pass through barriers created by polar winds and currents that were, until now, thought to be impenetrable,” Dr Fraser said.

“Our findings also indicate that plants and animals living on Antarctica could be more vulnerable to climate change than we suspected.” – Climate News Network

For more than a century, scientists believed that only humans could cross the hostile oceans to reach Antarctica. Some strands of alien seaweed tell another story.

LONDON, 19 July, 2018 – A foreign invader, a species of alien seaweed, has managed to cross the oceans to reach the frozen Antarctic shores. So scientists may have to give up a cherished belief: that Antarctica is inviolate.

For a century, researchers have assumed that the mix of ocean currents, distance and temperature have kept the Great White Continent shielded from invasion by Pacific or Atlantic flotsam.

But the discovery of strands of kelp on an Antarctic beach – seaweed that may have drifted for considerable periods and a distance of 20,000 kms before becoming stranded far from home – brings an end to that belief. And the discovery suggests that global warming could bring serious changes to Antarctic ecosystems.

“Our findings also indicate that plants and animals living on Antarctica could be more vulnerable to climate change than we suspected”

“This finding shows us that living plants and animals can reach Antarctica across the ocean, with temperate and sub-Antarctic marine species probably bombarding Antarctic coastlines all the time,” said Ceridwen Fraser, of the Australian National University.

“We always thought Antarctic plants and animals were distinct because they were isolated, but this research now suggests these differences are almost entirely due to environmental extremes, not isolation.”

Dr Fraser and her colleagues report in the journal Nature Climate Change that strands of southern bull kelp, Durvillaea antarctica, found by a Chilean scientist, must have floated 20,000 km from the Kerguelen Islands and South Georgia. The kelp was encrusted with barnacles, evidence of a long time adrift.

In fact, researchers believe, it may be evidence of the longest episode of “biological rafting” ever confirmed. The word raft is significant: such floating platforms could provide shelter and transport for other biological invaders.

Plastic next?

Until now, the assumption has been that the pattern of surface currents and westerly winds tends to drive drifting material northwards from Antarctica. The discovery suggests that if kelp can get there, so can floating driftwood, or plastic debris, or any other unwelcome visitor.

The researchers think large waves driven by Southern Ocean storms may have steered the kelp rafts over what had been considered a natural ocean barrier. Global warming has begun to change conditions in Antarctica, and the continent – considered the last great tract of terrain unmarked by human colonisation – could become increasingly vulnerable to change.

“This is an unequivocal demonstration that marine species from the north can reach Antarctica. To get there the kelp had to pass through barriers created by polar winds and currents that were, until now, thought to be impenetrable,” Dr Fraser said.

“Our findings also indicate that plants and animals living on Antarctica could be more vulnerable to climate change than we suspected.” – Climate News Network