Category Archives: Oceans

Heat makes ocean winds and waves fiercer

The seas are rising. Ocean winds and waves are growing in speed and force. The oceans could be feeling the heat.

LONDON, 1 May, 2019 − The great swells of the Pacific are beginning to swell even more as fiercer ocean winds and waves leave their mark. The breakers that crash on the storm beaches now do so with greater force. The white horses are gathering pace.

A 33-year-study of data from 31 satellites and 80 ocean buoys has confirmed suspicions. The extreme ocean winds are now fiercer, and the waves are getting measurably higher.

It is a given of global warming that as average planetary temperatures rise, then more energy is available for storm, rainfall and drought.

In the past century, because of ever-increasing combustion of fossil fuels that release growing quantities of greenhouse gases, average global temperatures have crept higher by 1°C and in three decades the speed of extreme winds in the Southern Ocean has increased by 8%, or 1.5 metres per second. Extreme waves have increased by 30cms, or 5%, over the same period.

“These changes have impacts that are felt all over the world. Storm waves can increase coastal erosion, putting coastal settlements and infrastructures at risk”

“Although increases of 5 and 8% might not seem like much, if sustained into the future such changes to our climate will have major impacts,” said Ian Young, an engineer at the University of Melbourne in Australia

He and a colleague report in the journal Science that they reached their conclusion on the basis of 4 billion observations made between 1985 and 2018.

“Flooding events are caused by storm surge and associated breaking waves. The increased sea level makes these events more serious and more frequent,” said Professor Young. “Increases in wave height, and changes in other properties such as wave direction, will further increase the probability of coastal flooding.”

Sea levels have been creeping ever higher, in large part because of the retreat of most of the planet’s great glaciers and the ever-increasing meltwater from Greenland and West Antarctica, and also as a simple matter of physics: as the oceans warm, the waters become less dense and sea levels rise.

Difficult measurements

Surfers and pleasure-seekers began to worry about the impact of global warming and climate change on wave patterns years ago. But seemingly simple phenomena such as the effects wave height and wind speed have in the open oceans on a world-wide basis are harder to measure.

Spanish oceanographers reported earlier this year that they were sure that ocean waves were gathering in force and strength, and European engineers have warned of the impact of more intense storms backed up by rising seas on the Atlantic ports and coastlines of the continent.

But there are problems: precision measurements have been made only recently. Oceanographers cannot be sure that they are not witnessing a natural cycle of ocean change, in which storm intensities slowly vary over a pattern of decades.

Since 1985 earth observation satellites have been equipped with altimeters to measure wave height and wind speed, radiometers to measure wind speed, and scatterometers to record wind speed and direction. The next problem has been calibrating data from a range of different satellites, and indeed the slightly different stories told by instruments on the same satellite.

Worse to come

But the Australian engineers report that they are now 90% confident that they can measure ocean change: violent storms now arrive with higher wave crests and more dangerous winds than they did in 1985, and although this is true worldwide, the effect is most pronounced in the great ocean that swirls around Antarctica.

The next challenge is to make estimates of how much more violent the worst sea storms are likely to become later in the century, as planetary average temperatures – and sea levels – continue to rise.

“These changes have impacts that are felt all over the world. Storm waves can increase coastal erosion, putting coastal settlements and infrastructures at risk,” Professor Young said.

“We need a better understanding of how much this change is due to long-term climate change, and how much is due to multi-decadal fluctuations or cycles.” − Climate News Network

The seas are rising. Ocean winds and waves are growing in speed and force. The oceans could be feeling the heat.

LONDON, 1 May, 2019 − The great swells of the Pacific are beginning to swell even more as fiercer ocean winds and waves leave their mark. The breakers that crash on the storm beaches now do so with greater force. The white horses are gathering pace.

A 33-year-study of data from 31 satellites and 80 ocean buoys has confirmed suspicions. The extreme ocean winds are now fiercer, and the waves are getting measurably higher.

It is a given of global warming that as average planetary temperatures rise, then more energy is available for storm, rainfall and drought.

In the past century, because of ever-increasing combustion of fossil fuels that release growing quantities of greenhouse gases, average global temperatures have crept higher by 1°C and in three decades the speed of extreme winds in the Southern Ocean has increased by 8%, or 1.5 metres per second. Extreme waves have increased by 30cms, or 5%, over the same period.

“These changes have impacts that are felt all over the world. Storm waves can increase coastal erosion, putting coastal settlements and infrastructures at risk”

“Although increases of 5 and 8% might not seem like much, if sustained into the future such changes to our climate will have major impacts,” said Ian Young, an engineer at the University of Melbourne in Australia

He and a colleague report in the journal Science that they reached their conclusion on the basis of 4 billion observations made between 1985 and 2018.

“Flooding events are caused by storm surge and associated breaking waves. The increased sea level makes these events more serious and more frequent,” said Professor Young. “Increases in wave height, and changes in other properties such as wave direction, will further increase the probability of coastal flooding.”

Sea levels have been creeping ever higher, in large part because of the retreat of most of the planet’s great glaciers and the ever-increasing meltwater from Greenland and West Antarctica, and also as a simple matter of physics: as the oceans warm, the waters become less dense and sea levels rise.

Difficult measurements

Surfers and pleasure-seekers began to worry about the impact of global warming and climate change on wave patterns years ago. But seemingly simple phenomena such as the effects wave height and wind speed have in the open oceans on a world-wide basis are harder to measure.

Spanish oceanographers reported earlier this year that they were sure that ocean waves were gathering in force and strength, and European engineers have warned of the impact of more intense storms backed up by rising seas on the Atlantic ports and coastlines of the continent.

But there are problems: precision measurements have been made only recently. Oceanographers cannot be sure that they are not witnessing a natural cycle of ocean change, in which storm intensities slowly vary over a pattern of decades.

Since 1985 earth observation satellites have been equipped with altimeters to measure wave height and wind speed, radiometers to measure wind speed, and scatterometers to record wind speed and direction. The next problem has been calibrating data from a range of different satellites, and indeed the slightly different stories told by instruments on the same satellite.

Worse to come

But the Australian engineers report that they are now 90% confident that they can measure ocean change: violent storms now arrive with higher wave crests and more dangerous winds than they did in 1985, and although this is true worldwide, the effect is most pronounced in the great ocean that swirls around Antarctica.

The next challenge is to make estimates of how much more violent the worst sea storms are likely to become later in the century, as planetary average temperatures – and sea levels – continue to rise.

“These changes have impacts that are felt all over the world. Storm waves can increase coastal erosion, putting coastal settlements and infrastructures at risk,” Professor Young said.

“We need a better understanding of how much this change is due to long-term climate change, and how much is due to multi-decadal fluctuations or cycles.” − Climate News Network

Cold-blooded sealife runs double heat risk

Extremes of heat are twice as risky for cold-blooded sealife as for other ectotherms. A hot rock could be safer than the deep sea.

LONDON, 29 April, 2019 – When it comes to global warming, there may no longer be plenty of fish in the sea: new research suggests that cold-blooded sealife may be twice as likely to be at risk in its natural habitat as land-dwelling ectotherms.

This finding is unexpected: the ocean is, in both area and volume, the single biggest living space on the planet. Fish that feel the heat can move towards the poles when temperatures get too high.

But when US researchers took a closer look at the data available on the thermal discomfort zones – those moments when cold-blooded creatures begin to overheat and need to find a safe, cool place in which to lie low – those spiders and lizards that survive in the tropics and temperate zones actually stand a better chance of finding somewhere to hide, and thus living through heatwaves, than their marine cousins.

“New conservation efforts will be needed if the ocean is going to continue supporting human well-being, nutrition and economic activity”

“We find that, globally, marine species are being eliminated from their habitats by warming temperatures twice as often as land species,” said Malin Pinsky, of Rutgers University in New Brunswick.

“The findings suggest that new conservation efforts will be needed if the ocean is going to continue supporting human well-being, nutrition and economic activity.”

He and colleagues report in the journal Nature that they searched the literature for detailed information on 400 species, and calculated the safe conditions for 88 marine and 294 land animals. They also identified the coolest temperatures available to each species during the hottest parts of the year.

More terrestrial refuges

And they found that, on average, fish and marine animals were more likely to live on the edge of temperatures that could become dangerously high. Land animals – insects and reptiles – could disappear into the forests, seek the shade or go underground: something sea creatures could not do.

That terrestrial reptiles and amphibians and marine animals are at risk is not news: researchers have already recorded significant movements of sea species in response to heat extremes off the Californian coast.

There has been repeated evidence that rising global temperature, as a consequence of greenhouse gas emissions from fossil fuel use, has begun to affect commercial fisheries, and other researchers have made it emphatically clear that only determined human action to contain global warming and protect breeding grounds can keep fish on the family supper table.

What most would not have expected was to find that land animals were less at risk, simply because they were land-dwellers.

Limited evidence

Research of this kind tends to deliver findings that can be challenged, and the authors concede that their conclusions are limited by the available evidence. Of 159 separate studies, 153 were in the northern hemisphere and 137 were from the temperate latitudes. Of their marine ectotherms, only 7% were pelagic: these are the fish – among them cod and tuna – that can swim to deeper, cooler layers when surface temperatures soar.

The remaining 93% included slow-moving bottom-dwellers such as lobsters, horseshoe crabs, abalone and snails, which may have nowhere left to go when life locally gets too hot to handle. The researchers make it clear that they are not talking about complete global extinctions of species: they choose the phrase “local extirpations”.

And they make it clear that land-dwelling cold-blooded animals are by no means safe from increasingly frequent, intense episodes of heat extremes driven by climate change: they would continue to be vulnerable to loss of what the researchers call “local refugia” – for example woodland cover – which “would make habitat fragmentation and changes in land use critical drivers of species loss on land.” – Climate News Network

Extremes of heat are twice as risky for cold-blooded sealife as for other ectotherms. A hot rock could be safer than the deep sea.

LONDON, 29 April, 2019 – When it comes to global warming, there may no longer be plenty of fish in the sea: new research suggests that cold-blooded sealife may be twice as likely to be at risk in its natural habitat as land-dwelling ectotherms.

This finding is unexpected: the ocean is, in both area and volume, the single biggest living space on the planet. Fish that feel the heat can move towards the poles when temperatures get too high.

But when US researchers took a closer look at the data available on the thermal discomfort zones – those moments when cold-blooded creatures begin to overheat and need to find a safe, cool place in which to lie low – those spiders and lizards that survive in the tropics and temperate zones actually stand a better chance of finding somewhere to hide, and thus living through heatwaves, than their marine cousins.

“New conservation efforts will be needed if the ocean is going to continue supporting human well-being, nutrition and economic activity”

“We find that, globally, marine species are being eliminated from their habitats by warming temperatures twice as often as land species,” said Malin Pinsky, of Rutgers University in New Brunswick.

“The findings suggest that new conservation efforts will be needed if the ocean is going to continue supporting human well-being, nutrition and economic activity.”

He and colleagues report in the journal Nature that they searched the literature for detailed information on 400 species, and calculated the safe conditions for 88 marine and 294 land animals. They also identified the coolest temperatures available to each species during the hottest parts of the year.

More terrestrial refuges

And they found that, on average, fish and marine animals were more likely to live on the edge of temperatures that could become dangerously high. Land animals – insects and reptiles – could disappear into the forests, seek the shade or go underground: something sea creatures could not do.

That terrestrial reptiles and amphibians and marine animals are at risk is not news: researchers have already recorded significant movements of sea species in response to heat extremes off the Californian coast.

There has been repeated evidence that rising global temperature, as a consequence of greenhouse gas emissions from fossil fuel use, has begun to affect commercial fisheries, and other researchers have made it emphatically clear that only determined human action to contain global warming and protect breeding grounds can keep fish on the family supper table.

What most would not have expected was to find that land animals were less at risk, simply because they were land-dwellers.

Limited evidence

Research of this kind tends to deliver findings that can be challenged, and the authors concede that their conclusions are limited by the available evidence. Of 159 separate studies, 153 were in the northern hemisphere and 137 were from the temperate latitudes. Of their marine ectotherms, only 7% were pelagic: these are the fish – among them cod and tuna – that can swim to deeper, cooler layers when surface temperatures soar.

The remaining 93% included slow-moving bottom-dwellers such as lobsters, horseshoe crabs, abalone and snails, which may have nowhere left to go when life locally gets too hot to handle. The researchers make it clear that they are not talking about complete global extinctions of species: they choose the phrase “local extirpations”.

And they make it clear that land-dwelling cold-blooded animals are by no means safe from increasingly frequent, intense episodes of heat extremes driven by climate change: they would continue to be vulnerable to loss of what the researchers call “local refugia” – for example woodland cover – which “would make habitat fragmentation and changes in land use critical drivers of species loss on land.” – Climate News Network

Fast Arctic melt could cost $70 trillion

Polar change, notably the fast Arctic melt, could impose huge costs on world economies. New evidence shows how rapidly the frozen north is changing.

LONDON, 26 April, 2019 – The northern reaches of the planet are undergoing very rapid change: the fast Arctic melt means the region is warming at twice the speed of the planetary average.

The loss of sea ice and land snow could tip the planet into a new and unprecedented cycle of climatic change and add yet another $70 trillion (£54 tn) to the estimated economic cost of global warming.

In yet another sombre statement of the challenge presented by climate change, driven by ever-increasing emissions of greenhouse gases from the fossil fuels that power the global economy, British, European and US researchers took a look at two manifestations of warming.

One is the growing levels of ancient carbon now being released into the atmosphere as the Arctic permafrost begins to melt. The other is the reduced reflection of solar radiation back into space as what had once been an expanse of snow and ice melts, to expose ever greater areas of light-absorbing blue sea, dark rock and scrubby tundra.

Abrupt surprises

The concern is with what the scientists like to call “non-linear transitions”. The fear is not that global warming will simply get more pronounced as more snow and ice disappears. The fear is that at some point the melting will reach a threshold that could tip the planet into a new climate regime that would be irreversible, and for which there has been no parallel in human history.

And if so, the costs in terms of climate disruption, heat waves, rising sea levels, harvest failures, more violent storms and more devastating floods and so on could start to soar.

The scientists report in the journal Nature Communications that if the nations of the world were to keep a promise made in Paris in 2015 to contain planetary warming to “well below” 2°C above the average for most of human history by the year 2100, the extra cost of Arctic ice loss would still tip $24 tn.

But on the evidence of national plans tabled so far, the world seems on course to hit 3°C by the century’s end, and the extra cost to the global economies is estimated at almost $70 tn.

“What we are witnessing is a major transport current faltering, which is bringing the world one step closer to a sea ice-free summer in the Arctic”

If the world goes on burning more and more fossil fuels – this is called the business-as-usual scenario – then global temperatures could rise to 4°C above the historic average by 2100. The bill for what the scientists call “the most expensive and least desirable scenario” is set at $2197 tn. And, they stress, their forecast $70 tn is just the extra cost of the melting Arctic.

They have not factored in all the other much-feared potential “tipping points” such as the loss of the tropical rainforests that absorb so much of the atmospheric carbon, the collapse of the great Atlantic current that distributes equatorial heat to temperate climates, the loss of the West Antarctic ice sheet, and other irreversible changes.

As they see it, even to contain global warming to 1.5°C by 2100 could cost a global $600 trillion.

And although the thawing of the permafrost and the opening of the Arctic Ocean would deliver mining and shipping opportunities, any such rewards would be dwarfed by the cost of the emissions from the thawing permafrost, and the reduction of what scientists call albedo: the reflectivity of pristine ice and snow that helps keep the Arctic frozen.

Model-based estimates

Research of this kind is based on vast numbers of simulations of the global economies under a range of scenarios, and the calculations of cost remain just that, estimates based on models of what nations might or might not do. The price economies must pay will be real enough, but the advanced accounting of what has yet to happen remains academic.

But the changes in the Arctic are far from academic, according to a series of new studies of what has been happening, and is happening right now.

●Researchers in California report in the Proceedings of the National Academy of Sciences that they have now reconstructed change in the Greenland ice sheet between 1972 and 2018, to estimate the loss of ice.

Fifty years ago, the northern hemisphere’s greatest sheet of ice was losing 47 billion tonnes of ice every year, and by the next decade 50 bn tonnes annually.

Sea levels raised

Since then the losses have risen almost six-fold, and since 2010 the island has been losing ice at the rate of 290 billion tonnes a year. So far, ice from Greenland alone has raised sea levels by almost 14 mm.

●German scientists have looked at the results of 15 years of observations by the Grace satellite system – the acronym stands for Gravity Recovery and Climate Experiment – which ended in 2018. They calculate that between April 2002 and June 2017, Greenland lost about 260 bn tonnes of ice each year, and Antarctica 140 bn tonnes.

They warn in the journal Nature Climate Change that melting at this rate could accelerate sea level rise to 10 mm a year – faster than at any time in the last 5,000 years – as a direct consequence of a warming climate.

●And the traffic of sea ice across the Arctic ocean has begun to falter, according to German oceanographers. The Transpolar Drift is a slow flow of new sea ice from the Siberian Arctic across the pole to the Fram Strait east of Greenland.

Melting too early

It has its place in the history of polar exploration: in 1893 the Norwegian explorer Fridtjof Nansen deliberately sailed his ship the Fram into the ice pack off Siberia and went with the floes across the Arctic.

The Drift is a kind of frozen ocean conveyor that carries nutrients, algae and sediments across the pole. But, researchers say in the journal Scientific Reports, this flow has started to vary. Most of the young ice off the Siberian coast now melts before it can leave its “nursery”. Once, half the ice from the Russian shelf completed the journey. Now, only one-fifth does.

“What we are witnessing is a major transport current faltering, which is bringing the world one step closer to a sea ice-free summer in the Arctic,” said Thomas Krumpen of the Alfred Wegener Institute, who led the study.

“The ice now leaving the Arctic through the Fram Strait is, on average, 30% thinner than it was 15 years ago.” – Climate News Network

Polar change, notably the fast Arctic melt, could impose huge costs on world economies. New evidence shows how rapidly the frozen north is changing.

LONDON, 26 April, 2019 – The northern reaches of the planet are undergoing very rapid change: the fast Arctic melt means the region is warming at twice the speed of the planetary average.

The loss of sea ice and land snow could tip the planet into a new and unprecedented cycle of climatic change and add yet another $70 trillion (£54 tn) to the estimated economic cost of global warming.

In yet another sombre statement of the challenge presented by climate change, driven by ever-increasing emissions of greenhouse gases from the fossil fuels that power the global economy, British, European and US researchers took a look at two manifestations of warming.

One is the growing levels of ancient carbon now being released into the atmosphere as the Arctic permafrost begins to melt. The other is the reduced reflection of solar radiation back into space as what had once been an expanse of snow and ice melts, to expose ever greater areas of light-absorbing blue sea, dark rock and scrubby tundra.

Abrupt surprises

The concern is with what the scientists like to call “non-linear transitions”. The fear is not that global warming will simply get more pronounced as more snow and ice disappears. The fear is that at some point the melting will reach a threshold that could tip the planet into a new climate regime that would be irreversible, and for which there has been no parallel in human history.

And if so, the costs in terms of climate disruption, heat waves, rising sea levels, harvest failures, more violent storms and more devastating floods and so on could start to soar.

The scientists report in the journal Nature Communications that if the nations of the world were to keep a promise made in Paris in 2015 to contain planetary warming to “well below” 2°C above the average for most of human history by the year 2100, the extra cost of Arctic ice loss would still tip $24 tn.

But on the evidence of national plans tabled so far, the world seems on course to hit 3°C by the century’s end, and the extra cost to the global economies is estimated at almost $70 tn.

“What we are witnessing is a major transport current faltering, which is bringing the world one step closer to a sea ice-free summer in the Arctic”

If the world goes on burning more and more fossil fuels – this is called the business-as-usual scenario – then global temperatures could rise to 4°C above the historic average by 2100. The bill for what the scientists call “the most expensive and least desirable scenario” is set at $2197 tn. And, they stress, their forecast $70 tn is just the extra cost of the melting Arctic.

They have not factored in all the other much-feared potential “tipping points” such as the loss of the tropical rainforests that absorb so much of the atmospheric carbon, the collapse of the great Atlantic current that distributes equatorial heat to temperate climates, the loss of the West Antarctic ice sheet, and other irreversible changes.

As they see it, even to contain global warming to 1.5°C by 2100 could cost a global $600 trillion.

And although the thawing of the permafrost and the opening of the Arctic Ocean would deliver mining and shipping opportunities, any such rewards would be dwarfed by the cost of the emissions from the thawing permafrost, and the reduction of what scientists call albedo: the reflectivity of pristine ice and snow that helps keep the Arctic frozen.

Model-based estimates

Research of this kind is based on vast numbers of simulations of the global economies under a range of scenarios, and the calculations of cost remain just that, estimates based on models of what nations might or might not do. The price economies must pay will be real enough, but the advanced accounting of what has yet to happen remains academic.

But the changes in the Arctic are far from academic, according to a series of new studies of what has been happening, and is happening right now.

●Researchers in California report in the Proceedings of the National Academy of Sciences that they have now reconstructed change in the Greenland ice sheet between 1972 and 2018, to estimate the loss of ice.

Fifty years ago, the northern hemisphere’s greatest sheet of ice was losing 47 billion tonnes of ice every year, and by the next decade 50 bn tonnes annually.

Sea levels raised

Since then the losses have risen almost six-fold, and since 2010 the island has been losing ice at the rate of 290 billion tonnes a year. So far, ice from Greenland alone has raised sea levels by almost 14 mm.

●German scientists have looked at the results of 15 years of observations by the Grace satellite system – the acronym stands for Gravity Recovery and Climate Experiment – which ended in 2018. They calculate that between April 2002 and June 2017, Greenland lost about 260 bn tonnes of ice each year, and Antarctica 140 bn tonnes.

They warn in the journal Nature Climate Change that melting at this rate could accelerate sea level rise to 10 mm a year – faster than at any time in the last 5,000 years – as a direct consequence of a warming climate.

●And the traffic of sea ice across the Arctic ocean has begun to falter, according to German oceanographers. The Transpolar Drift is a slow flow of new sea ice from the Siberian Arctic across the pole to the Fram Strait east of Greenland.

Melting too early

It has its place in the history of polar exploration: in 1893 the Norwegian explorer Fridtjof Nansen deliberately sailed his ship the Fram into the ice pack off Siberia and went with the floes across the Arctic.

The Drift is a kind of frozen ocean conveyor that carries nutrients, algae and sediments across the pole. But, researchers say in the journal Scientific Reports, this flow has started to vary. Most of the young ice off the Siberian coast now melts before it can leave its “nursery”. Once, half the ice from the Russian shelf completed the journey. Now, only one-fifth does.

“What we are witnessing is a major transport current faltering, which is bringing the world one step closer to a sea ice-free summer in the Arctic,” said Thomas Krumpen of the Alfred Wegener Institute, who led the study.

“The ice now leaving the Arctic through the Fram Strait is, on average, 30% thinner than it was 15 years ago.” – Climate News Network

Gulf Stream slowdown may bring later cold

The Gulf Stream is weakening, and Europe could expect a prolonged cold spell as the world warms – but not the day after tomorrow.

LONDON, 25 March, 2019 – As the Gulf Stream weakens in a rapidly warming world, north-western Europe could paradoxically become cooler. There is, however, a time lag between those two climate change-related events, and US scientists now think they know how long that could be.
It could be as much as 400 years.

They know this because the world has warmed and cooled before, and as the difference between tropics and Arctic narrows, there is a change in the so-called Atlantic conveyor, an important part of the climate machine.

This vast Atlantic current carries a steady flow of warm water to the far north, making north-western Europe up to 5°C warmer than its latitude would otherwise dictate. Then, as it meets colder, denser Arctic waters, it dives, to carry its burden of surface carbon to the depths, and then flows southwards again.

This phenomenon, known as the Atlantic Meridional Overturning Circulation, or AMOC, is in effect Europe’s bespoke heating system: Britain’s chief scientific adviser once calculated that it delivers to the UK alone the warmth of 27,000 power stations.

“There are some precursors in the ocean, so we should be watching the ocean”

But evidence from climate history shows that this heating has been turned off a number of times. Europe was plunged into a cold snap 13,000 years ago during a period known as the Younger Dryas and then warmed up about 11,000 years ago.

New and sophisticated studies of fossil carbon show that anybody taking notes at the time might have observed the warning signs. About 400 years before the abrupt shift to a frosty spell, the Atlantic current weakened. And it started to strengthen again about four centuries before the world warmed.

The study, published in the journal Nature Communications, confirms what climate scientists have always known: any sudden catastrophic return of the Ice Ages – dramatised in Hollywood’s notorious 2004 climate change movie The Day After Tomorrow – won’t happen at action movie pace. But it will happen over decades, and now seemingly with several centuries of advance notice.

“Our reconstructions indicate that there are clear climate precursors provided by the ocean state – like warning signs, so to speak,” said Francesco Muschitiello, then of the Lamont-Doherty Earth Observatory at Columbia University, US, and now at the University of Cambridge in the UK, who led the research.

Timing established

Climate scientists have clear dates for the timing of the Younger Dryas event: ice cores from the Arctic show both that Greenland’s temperature fell by 6°C or more at the beginning of the cycle, and that it rose by at least 8°C at its end.

To time the changes in the ocean current, they used carbon-dating techniques to identify a pattern of change in the marine sediments in the Norwegian Sea.

Since marine sediments settle very slowly, over very long periods of time, they needed a more precise “clock” to help calibrate their calculations: they found this in the fossilised ancient plants in a Scandinavian lake.

The isotope carbon-14 is pulled directly from the atmosphere each season by growing foliage. It decays at a predictable rate, and the amount of surviving C14 delivered a reliable clock. The identification of two volcanic ash layers from eruptions in Iceland, in both lake and seabed, provided yet more confidence in the timings. From these factors, the researchers were able to identify a slowdown in the transport of carbon from surface to the deep – and thus a slowdown in the current.

Long wait

The research confirms a link between ocean circulation patterns and northern hemisphere climate shifts: it provides evidence of what could be a considerable interval between the two.

Researchers have repeatedly warned that the Atlantic current seemed to be slowing, in response to global warming driven by profligate fossil fuel use by humankind, and that the consequences of continued slowdown could be very uncomfortable for hundreds of millions.

If the evidence from the Younger Dryas provides a sure parallel to today’s conditions, then Europeans might have time to prepare.

“It is clear that there are some precursors in the ocean, so we should be watching the ocean,” said Dr Muschitiello. “The mere fact that AMOC has been slowing down, that should be a concern based on what we have found.” – Climate News Network

The Gulf Stream is weakening, and Europe could expect a prolonged cold spell as the world warms – but not the day after tomorrow.

LONDON, 25 March, 2019 – As the Gulf Stream weakens in a rapidly warming world, north-western Europe could paradoxically become cooler. There is, however, a time lag between those two climate change-related events, and US scientists now think they know how long that could be.
It could be as much as 400 years.

They know this because the world has warmed and cooled before, and as the difference between tropics and Arctic narrows, there is a change in the so-called Atlantic conveyor, an important part of the climate machine.

This vast Atlantic current carries a steady flow of warm water to the far north, making north-western Europe up to 5°C warmer than its latitude would otherwise dictate. Then, as it meets colder, denser Arctic waters, it dives, to carry its burden of surface carbon to the depths, and then flows southwards again.

This phenomenon, known as the Atlantic Meridional Overturning Circulation, or AMOC, is in effect Europe’s bespoke heating system: Britain’s chief scientific adviser once calculated that it delivers to the UK alone the warmth of 27,000 power stations.

“There are some precursors in the ocean, so we should be watching the ocean”

But evidence from climate history shows that this heating has been turned off a number of times. Europe was plunged into a cold snap 13,000 years ago during a period known as the Younger Dryas and then warmed up about 11,000 years ago.

New and sophisticated studies of fossil carbon show that anybody taking notes at the time might have observed the warning signs. About 400 years before the abrupt shift to a frosty spell, the Atlantic current weakened. And it started to strengthen again about four centuries before the world warmed.

The study, published in the journal Nature Communications, confirms what climate scientists have always known: any sudden catastrophic return of the Ice Ages – dramatised in Hollywood’s notorious 2004 climate change movie The Day After Tomorrow – won’t happen at action movie pace. But it will happen over decades, and now seemingly with several centuries of advance notice.

“Our reconstructions indicate that there are clear climate precursors provided by the ocean state – like warning signs, so to speak,” said Francesco Muschitiello, then of the Lamont-Doherty Earth Observatory at Columbia University, US, and now at the University of Cambridge in the UK, who led the research.

Timing established

Climate scientists have clear dates for the timing of the Younger Dryas event: ice cores from the Arctic show both that Greenland’s temperature fell by 6°C or more at the beginning of the cycle, and that it rose by at least 8°C at its end.

To time the changes in the ocean current, they used carbon-dating techniques to identify a pattern of change in the marine sediments in the Norwegian Sea.

Since marine sediments settle very slowly, over very long periods of time, they needed a more precise “clock” to help calibrate their calculations: they found this in the fossilised ancient plants in a Scandinavian lake.

The isotope carbon-14 is pulled directly from the atmosphere each season by growing foliage. It decays at a predictable rate, and the amount of surviving C14 delivered a reliable clock. The identification of two volcanic ash layers from eruptions in Iceland, in both lake and seabed, provided yet more confidence in the timings. From these factors, the researchers were able to identify a slowdown in the transport of carbon from surface to the deep – and thus a slowdown in the current.

Long wait

The research confirms a link between ocean circulation patterns and northern hemisphere climate shifts: it provides evidence of what could be a considerable interval between the two.

Researchers have repeatedly warned that the Atlantic current seemed to be slowing, in response to global warming driven by profligate fossil fuel use by humankind, and that the consequences of continued slowdown could be very uncomfortable for hundreds of millions.

If the evidence from the Younger Dryas provides a sure parallel to today’s conditions, then Europeans might have time to prepare.

“It is clear that there are some precursors in the ocean, so we should be watching the ocean,” said Dr Muschitiello. “The mere fact that AMOC has been slowing down, that should be a concern based on what we have found.” – Climate News Network

Ocean heatwaves drive more fish north

As sea water warms, sub-tropical fish swim north. They may do so more often as ocean heatwaves add to the sweltering.

LONDON, 22 March, 2019 – With a little help from ocean heatwaves, the world’s seas are changing. Researchers in California can now name 37 species that have shifted their range further north than ever before in response to unusually hot summers in the eastern Pacific.

In the years 2014-2016, the pelagic red crab Pleuroncodes planipes was spotted off Agate Beach, Oregon, a full 595 kilometres further north than ever before. A deepwater invertebrate called the black-tipped spiny dorid Acanthodoris rhodoceras also made it to Oregon, 620 kilometres from what had previously been its most northerly range.

Both were joined by an assortment of snails, sea butterflies, pteropods, nudibranchs, red algae, sea anemones, siphonophores, fish, dolphins, sea turtles and other citizens of the sub-tropical seas in making the great trek north to what had once been cooler waters, the researchers record in the journal Scientific Reports.

They collected their data in the wake of two significant changes in water temperatures. One involved a mysterious “blob” of warm water that made the journey south from the Gulf of Alaska, the other a blister of warm water on the way north associated with a natural phenomenon known as El Niño in 2015.

“Just as atmospheric heatwaves can destroy crops, forests and animal populations, marine heatwaves can devastate ocean ecosystems”

Altogether they recorded 67 rare, warm water sightings off California and Oregon: of these 37 had never been observed so far north.

“Against a backdrop of climate change, we hope southern species will track northward because that’s necessary for their persistence and survival,” said Eric Sanford, an ecologist at the University of California, Davis, who led the study.

“It’s perhaps a glimpse of what northern California’s coast might look like in the future as ocean temperatures continue to warm.”

And just in case anyone thinks the temperatures in 2014-2016 were a freak – a response to an unprecedented pattern of weather events – a second set of scientists has uncomfortable news.

Extreme heat increases

Not only were the oceans in 2018 hotter than at any time  since records began, but periods of extreme heat on the high seas – that is, marine heatwaves – are on the increase around the globe.

Between 1987 and 2016, the number of heatwave days per year was 54% higher than for the years 1925 to 1954. And this is true not just for the eastern Pacific but for many regions in the Atlantic and Indian Oceans as well.

This is likely to be bad news for individual species, bad news for ecosystems and bad news for the key species – kelps, corals, sea grasses and so on – that provide vital habitats for marine life, they report in the journal Nature Climate Change.

The researchers define marine heatwaves as episodes in which sea surface temperatures exceed the seasonal norm for at least five consecutive days.

Marine threat

Increasing heatwaves over land have already been identified as potentially a threat to human life. They will menace marine life as well, the scientists say.

“Ocean ecosystems currently face a number of threats, including overfishing, acidification and plastic pollution, but periods of extreme temperatures can cause rapid and profound ecological changes, leading to loss of habitat, local extinctions, reduced fisheries catches and altered food webs”, said Dan Smale, of the UK Marine Biological Association, who led the research.

“The major concern is that the oceans have warmed significantly as a consequence of manmade climate change, so that marine heatwaves have become more frequent and will likely intensify over the coming decades.

“Just as atmospheric heatwaves can destroy crops, forests and animal populations, marine heatwaves can devastate ocean ecosystems.” – Climate News Network

As sea water warms, sub-tropical fish swim north. They may do so more often as ocean heatwaves add to the sweltering.

LONDON, 22 March, 2019 – With a little help from ocean heatwaves, the world’s seas are changing. Researchers in California can now name 37 species that have shifted their range further north than ever before in response to unusually hot summers in the eastern Pacific.

In the years 2014-2016, the pelagic red crab Pleuroncodes planipes was spotted off Agate Beach, Oregon, a full 595 kilometres further north than ever before. A deepwater invertebrate called the black-tipped spiny dorid Acanthodoris rhodoceras also made it to Oregon, 620 kilometres from what had previously been its most northerly range.

Both were joined by an assortment of snails, sea butterflies, pteropods, nudibranchs, red algae, sea anemones, siphonophores, fish, dolphins, sea turtles and other citizens of the sub-tropical seas in making the great trek north to what had once been cooler waters, the researchers record in the journal Scientific Reports.

They collected their data in the wake of two significant changes in water temperatures. One involved a mysterious “blob” of warm water that made the journey south from the Gulf of Alaska, the other a blister of warm water on the way north associated with a natural phenomenon known as El Niño in 2015.

“Just as atmospheric heatwaves can destroy crops, forests and animal populations, marine heatwaves can devastate ocean ecosystems”

Altogether they recorded 67 rare, warm water sightings off California and Oregon: of these 37 had never been observed so far north.

“Against a backdrop of climate change, we hope southern species will track northward because that’s necessary for their persistence and survival,” said Eric Sanford, an ecologist at the University of California, Davis, who led the study.

“It’s perhaps a glimpse of what northern California’s coast might look like in the future as ocean temperatures continue to warm.”

And just in case anyone thinks the temperatures in 2014-2016 were a freak – a response to an unprecedented pattern of weather events – a second set of scientists has uncomfortable news.

Extreme heat increases

Not only were the oceans in 2018 hotter than at any time  since records began, but periods of extreme heat on the high seas – that is, marine heatwaves – are on the increase around the globe.

Between 1987 and 2016, the number of heatwave days per year was 54% higher than for the years 1925 to 1954. And this is true not just for the eastern Pacific but for many regions in the Atlantic and Indian Oceans as well.

This is likely to be bad news for individual species, bad news for ecosystems and bad news for the key species – kelps, corals, sea grasses and so on – that provide vital habitats for marine life, they report in the journal Nature Climate Change.

The researchers define marine heatwaves as episodes in which sea surface temperatures exceed the seasonal norm for at least five consecutive days.

Marine threat

Increasing heatwaves over land have already been identified as potentially a threat to human life. They will menace marine life as well, the scientists say.

“Ocean ecosystems currently face a number of threats, including overfishing, acidification and plastic pollution, but periods of extreme temperatures can cause rapid and profound ecological changes, leading to loss of habitat, local extinctions, reduced fisheries catches and altered food webs”, said Dan Smale, of the UK Marine Biological Association, who led the research.

“The major concern is that the oceans have warmed significantly as a consequence of manmade climate change, so that marine heatwaves have become more frequent and will likely intensify over the coming decades.

“Just as atmospheric heatwaves can destroy crops, forests and animal populations, marine heatwaves can devastate ocean ecosystems.” – Climate News Network

Oceanic carbon uptake could falter

What does oceanic carbon uptake achieve? Greenhouse gas that sinks below the waves slows global warming a little and makes the water more acidic.

LONDON, 20 March, 2019 − Scientists can now put a measure to the role of the waves as a climate shock absorber: they estimate that oceanic carbon uptake by the deep blue seas has consumed 34 billion tonnes of man-made carbon from the atmosphere between the years 1994 and 2007.

This is just about 31% of all the carbon emitted in that time by car exhausts, power station chimneys, aircraft, ships, tractors and scorched forest, as human economies expand and ever more fossil fuel is consumed.

This confident figure is based on a global survey of the chemistry and other physical properties of the ocean by scientists from seven nations on more than 50 research cruises, taking measurements of the ocean from the surface to a depth of six kilometres.

The researchers report in the journal Science that they already had the results of a global carbon survey of the oceans conducted at the close of the last century, and had calculated that from the dawn of the Industrial Revolution – when humans started using coal, and then oil and gas – to 1994, the oceans had already absorbed 118 billion tonnes.

“The marine sink does not just respond to the increase in atmospheric CO2. Its substantial sensitivity to climate variations suggests a significant potential for feedbacks”

For the latest exercise, they developed a statistical tool that helped them make the distinction between the man-made and the natural atmospheric carbon dioxide always found dissolved in water.

The good news is that the ocean remains for the moment a stable component of the planet’s carbon budget: overall, as more man-made carbon is emitted from exhausts and chimneys, the ocean takes up proportionally more.

The bad news is that this may not go on for ever. At some point, the planet’s seas could become saturated with carbon, leaving ever more in the atmosphere to accelerate global warming to ever more alarming temperatures.

And there is a second unhappy consequence: the more carbon dioxide absorbed by the oceans, the more the sea shifts towards a weak solution of carbonic acid, with potentially calamitous consequences both for marine life and for commercial fisheries.

Research like this is essentially of academic interest: it adds precision to the big picture of a vast ocean that absorbs carbon dioxide, and overturning currents that take it to great depths, and out of atmospheric circulation.

An active moderator

But it is also a reminder that the ocean plays an active role in moderating planetary temperatures, absorbing ever greater quantities of heat and responding with fiercer levels of energy.

It also confirms that although, on average, the high seas are responding to atmospheric change as expected, different ocean basins can vary: the North Atlantic actually absorbed 20% less CO2 than expected between 1994 and 2007, probably thanks to the slowing of the North Atlantic Meridional Overturning Circulation at the time.

And, the researchers say, the acidification of the oceans is on the increase, to depths of 3000 metres. The next step is to understand a little better the interplay between ocean, atmosphere and human emissions of greenhouse gases.

“We learned that the marine sink does not just respond to the increase in atmospheric CO2,” said Nicolas Gruber of the Swiss Federal Institute of Technology, always known as ETH Zurich, who led the study.

“Its substantial sensitivity to climate variations suggests a significant potential for feedbacks with the ongoing change in climate.” − Climate News Network

What does oceanic carbon uptake achieve? Greenhouse gas that sinks below the waves slows global warming a little and makes the water more acidic.

LONDON, 20 March, 2019 − Scientists can now put a measure to the role of the waves as a climate shock absorber: they estimate that oceanic carbon uptake by the deep blue seas has consumed 34 billion tonnes of man-made carbon from the atmosphere between the years 1994 and 2007.

This is just about 31% of all the carbon emitted in that time by car exhausts, power station chimneys, aircraft, ships, tractors and scorched forest, as human economies expand and ever more fossil fuel is consumed.

This confident figure is based on a global survey of the chemistry and other physical properties of the ocean by scientists from seven nations on more than 50 research cruises, taking measurements of the ocean from the surface to a depth of six kilometres.

The researchers report in the journal Science that they already had the results of a global carbon survey of the oceans conducted at the close of the last century, and had calculated that from the dawn of the Industrial Revolution – when humans started using coal, and then oil and gas – to 1994, the oceans had already absorbed 118 billion tonnes.

“The marine sink does not just respond to the increase in atmospheric CO2. Its substantial sensitivity to climate variations suggests a significant potential for feedbacks”

For the latest exercise, they developed a statistical tool that helped them make the distinction between the man-made and the natural atmospheric carbon dioxide always found dissolved in water.

The good news is that the ocean remains for the moment a stable component of the planet’s carbon budget: overall, as more man-made carbon is emitted from exhausts and chimneys, the ocean takes up proportionally more.

The bad news is that this may not go on for ever. At some point, the planet’s seas could become saturated with carbon, leaving ever more in the atmosphere to accelerate global warming to ever more alarming temperatures.

And there is a second unhappy consequence: the more carbon dioxide absorbed by the oceans, the more the sea shifts towards a weak solution of carbonic acid, with potentially calamitous consequences both for marine life and for commercial fisheries.

Research like this is essentially of academic interest: it adds precision to the big picture of a vast ocean that absorbs carbon dioxide, and overturning currents that take it to great depths, and out of atmospheric circulation.

An active moderator

But it is also a reminder that the ocean plays an active role in moderating planetary temperatures, absorbing ever greater quantities of heat and responding with fiercer levels of energy.

It also confirms that although, on average, the high seas are responding to atmospheric change as expected, different ocean basins can vary: the North Atlantic actually absorbed 20% less CO2 than expected between 1994 and 2007, probably thanks to the slowing of the North Atlantic Meridional Overturning Circulation at the time.

And, the researchers say, the acidification of the oceans is on the increase, to depths of 3000 metres. The next step is to understand a little better the interplay between ocean, atmosphere and human emissions of greenhouse gases.

“We learned that the marine sink does not just respond to the increase in atmospheric CO2,” said Nicolas Gruber of the Swiss Federal Institute of Technology, always known as ETH Zurich, who led the study.

“Its substantial sensitivity to climate variations suggests a significant potential for feedbacks with the ongoing change in climate.” − Climate News Network

More acidic seas devour marine food web

As more acidic seas spread across the globe, conditions for survival start to change. That could close vast volumes of ocean for vital forms of life.

LONDON, 13 March, 2019 – By the close of the century, parts of the Southern Ocean could become impoverished as more acidic seas displace abundant marine food resources. Tiny sea snails that form the basis of the food supply for one of the world’s richest ecosystems could disappear because the depth at which they can form their shells will have shifted.

Right now, in Antarctic waters, creatures known as pteropods can exploit the calcium carbonate dissolved in the oceans down to a depth of 1000 metres to grow their shells.

But as atmospheric carbon dioxide levels soar, as a consequence of profligate use of fossil fuels by humankind, the chemistry of the oceans will shift towards the acidic.

The ratios of two kinds of carbonate – calcite and aragonite – will alter. And by 2100, there won’t be enough aragonite.

“A pocket of corrosive water will sit just below the surface, making life difficult for these communities of primarily surface-dwelling organisms”

Right now, pteropods flourish in the top 300 metres of the ocean. By 2100, the survival zone for the pteropods will end at a depth of 83 metres.

And, scientists warn in the journal Nature Climate Change, this could “change food web dynamics and have cascading effects on global ocean ecosystems.” In other words, the larger fish and marine mammals that feed on the smaller creatures that in turn depend on a basic diet of pteropods will have nothing to eat.

And that can only be bad news for global fisheries.

All shelled marine creatures – the tiny coccolithophores that die and leave their shells as chalk, the clams and molluscs, the foraminifera that float on the surface or coat the rocks and the seafloor, and the corals that are the basis for rich tropical ecosystems, all depend on the right levels of calcite and aragonite to form their exoskeletons.

The oceans are the biggest living space on the planet: the waves cover 70% of all living space and the depth of the deepest trenches is far greater than the highest terrestrial mountain ranges.

Origin of life

The oceans are the crucible in which life first emerged, and the oceans ultimately provided the sediments from which humankind has built its cities.

US and Norwegian scientists chose one species with precise needs in one reach of ocean as an indicator or what climate change driven by ever greater levels of the greenhouse gas carbon dioxide could do to an ocean ecosystem.

They found that what they called the “aragonite saturation horizon” became dramatically shallower as the seas became more acidic.

“These calcifying organisms will struggle to build and maintain their shells as acidification proceeds,” said Nicole Lovenduski, of the University of Colorado at Boulder, one of the researchers.

Inevitable result

“In the future, a pocket of corrosive water will sit just below the surface, making life difficult for these communities of primarily surface-dwelling organisms.”

As the world warms, acidification of the oceans becomes inevitable. Researchers have repeatedly warned that such change can only diminish ocean life, harm the coral reefs and kelp forests that shelter the rich biodiversity of sea creatures, change the behaviour of fish and some kinds of shrimp and threaten the shellfish harvest.

But for the first time, scientists have been able to model the impact of atmospheric change on the ocean chemistry in one zone at precise depths. The message is that right now, the pteropods have plenty of sea space for survival. But the aragonite saturation horizon may have already begun to shift in some places: perhaps as early as 2006, or as late as 2038. Once change begins, it will continue.

“If emissions were curbed tomorrow, this suddenly shallow horizon would still appear, even if possibly delayed,” said Dr Lovenduski. “And that, inevitably, along with lack of time for organisms to adapt, is most concerning.” – Climate News Network

As more acidic seas spread across the globe, conditions for survival start to change. That could close vast volumes of ocean for vital forms of life.

LONDON, 13 March, 2019 – By the close of the century, parts of the Southern Ocean could become impoverished as more acidic seas displace abundant marine food resources. Tiny sea snails that form the basis of the food supply for one of the world’s richest ecosystems could disappear because the depth at which they can form their shells will have shifted.

Right now, in Antarctic waters, creatures known as pteropods can exploit the calcium carbonate dissolved in the oceans down to a depth of 1000 metres to grow their shells.

But as atmospheric carbon dioxide levels soar, as a consequence of profligate use of fossil fuels by humankind, the chemistry of the oceans will shift towards the acidic.

The ratios of two kinds of carbonate – calcite and aragonite – will alter. And by 2100, there won’t be enough aragonite.

“A pocket of corrosive water will sit just below the surface, making life difficult for these communities of primarily surface-dwelling organisms”

Right now, pteropods flourish in the top 300 metres of the ocean. By 2100, the survival zone for the pteropods will end at a depth of 83 metres.

And, scientists warn in the journal Nature Climate Change, this could “change food web dynamics and have cascading effects on global ocean ecosystems.” In other words, the larger fish and marine mammals that feed on the smaller creatures that in turn depend on a basic diet of pteropods will have nothing to eat.

And that can only be bad news for global fisheries.

All shelled marine creatures – the tiny coccolithophores that die and leave their shells as chalk, the clams and molluscs, the foraminifera that float on the surface or coat the rocks and the seafloor, and the corals that are the basis for rich tropical ecosystems, all depend on the right levels of calcite and aragonite to form their exoskeletons.

The oceans are the biggest living space on the planet: the waves cover 70% of all living space and the depth of the deepest trenches is far greater than the highest terrestrial mountain ranges.

Origin of life

The oceans are the crucible in which life first emerged, and the oceans ultimately provided the sediments from which humankind has built its cities.

US and Norwegian scientists chose one species with precise needs in one reach of ocean as an indicator or what climate change driven by ever greater levels of the greenhouse gas carbon dioxide could do to an ocean ecosystem.

They found that what they called the “aragonite saturation horizon” became dramatically shallower as the seas became more acidic.

“These calcifying organisms will struggle to build and maintain their shells as acidification proceeds,” said Nicole Lovenduski, of the University of Colorado at Boulder, one of the researchers.

Inevitable result

“In the future, a pocket of corrosive water will sit just below the surface, making life difficult for these communities of primarily surface-dwelling organisms.”

As the world warms, acidification of the oceans becomes inevitable. Researchers have repeatedly warned that such change can only diminish ocean life, harm the coral reefs and kelp forests that shelter the rich biodiversity of sea creatures, change the behaviour of fish and some kinds of shrimp and threaten the shellfish harvest.

But for the first time, scientists have been able to model the impact of atmospheric change on the ocean chemistry in one zone at precise depths. The message is that right now, the pteropods have plenty of sea space for survival. But the aragonite saturation horizon may have already begun to shift in some places: perhaps as early as 2006, or as late as 2038. Once change begins, it will continue.

“If emissions were curbed tomorrow, this suddenly shallow horizon would still appear, even if possibly delayed,” said Dr Lovenduski. “And that, inevitably, along with lack of time for organisms to adapt, is most concerning.” – Climate News Network

Pacific climate wobble speeds Arctic ice melt

Thanks to a natural sea temperature cycle, a Pacific climate wobble, the Arctic Ocean could be ice-free in the summer in a decade or two.

LONDON, 6 March, 2019 – Sunlit skies and bright blue water could come earlier to the Arctic – much earlier, thanks to a distant Pacific climate wobble.

Scientists now think that the Arctic Ocean could be effectively ice-free within the next 20 years, opening it to sea lanes across the polar waters between Europe, the US and east Asia.

Climate researchers have repeatedly warned, in the last two decades, that because of global warming the ice sheet that masks the Arctic Ocean has been thinning and could in effect vanish altogether in summertime by 2050.

New research has brought forward the prediction date. And this time the effective agency is not just global warming driven by profligate combustion of fossil fuels worldwide, but a natural cyclic phenomenon known to oceanographers as the interdecadal Pacific oscillation, or IPO.

“The trajectory is towards becoming ice-free in the summer …  there’s more chance of it being on the earlier end of that window than the later end”

Over a cycle of between one to three decades, the average ocean temperatures of the north Pacific shift up or down by about 0.5°C.

And a new study in the journal Geophysical Research Letters pinpoints the state of the present cycle: the Pacific ended its cold phase and started to warm up about five years ago.

James Screen of the University of Exeter, UK, and a colleague used computer modelling to merge the continuous upward rise in global average temperatures as a consequence of the build-up of greenhouse gases in the atmosphere with the pattern of predicted natural change in ocean surface temperatures to identify the moment when the summer ice will have melted.

The phrase “ice-free” is not a simple one, because some sea ice always remains, but oceanographers and glaciologists have their own definition: it happens when the area of summer sea ice falls below a million square kilometres.

Dramatic change likely

And this is now likely to happen some time between 2030 and 2050. Any argument is not about if, but when. The Arctic is just about the fastest-warming region of the planet, and in 2016 polar sea ice in both hemispheres  reached a record low: an area of ice the size of Mexico was lost.

Temperatures in the Arctic were recorded as up to 20°C above the average for some of the winter months. The long-term consequences are unpredictable, but since both ocean current and air movement are driven by the difference between equatorial and polar temperatures, dramatic climate change is likely to follow.

“The trajectory is towards becoming ice-free in the summer, but there is uncertainty as to when that is going to occur,” Dr Screen said.

“You can hedge your bets. The shift in the IPO means there’s more chance of it being on the earlier end of that window than the later end.” – Climate News Network

Thanks to a natural sea temperature cycle, a Pacific climate wobble, the Arctic Ocean could be ice-free in the summer in a decade or two.

LONDON, 6 March, 2019 – Sunlit skies and bright blue water could come earlier to the Arctic – much earlier, thanks to a distant Pacific climate wobble.

Scientists now think that the Arctic Ocean could be effectively ice-free within the next 20 years, opening it to sea lanes across the polar waters between Europe, the US and east Asia.

Climate researchers have repeatedly warned, in the last two decades, that because of global warming the ice sheet that masks the Arctic Ocean has been thinning and could in effect vanish altogether in summertime by 2050.

New research has brought forward the prediction date. And this time the effective agency is not just global warming driven by profligate combustion of fossil fuels worldwide, but a natural cyclic phenomenon known to oceanographers as the interdecadal Pacific oscillation, or IPO.

“The trajectory is towards becoming ice-free in the summer …  there’s more chance of it being on the earlier end of that window than the later end”

Over a cycle of between one to three decades, the average ocean temperatures of the north Pacific shift up or down by about 0.5°C.

And a new study in the journal Geophysical Research Letters pinpoints the state of the present cycle: the Pacific ended its cold phase and started to warm up about five years ago.

James Screen of the University of Exeter, UK, and a colleague used computer modelling to merge the continuous upward rise in global average temperatures as a consequence of the build-up of greenhouse gases in the atmosphere with the pattern of predicted natural change in ocean surface temperatures to identify the moment when the summer ice will have melted.

The phrase “ice-free” is not a simple one, because some sea ice always remains, but oceanographers and glaciologists have their own definition: it happens when the area of summer sea ice falls below a million square kilometres.

Dramatic change likely

And this is now likely to happen some time between 2030 and 2050. Any argument is not about if, but when. The Arctic is just about the fastest-warming region of the planet, and in 2016 polar sea ice in both hemispheres  reached a record low: an area of ice the size of Mexico was lost.

Temperatures in the Arctic were recorded as up to 20°C above the average for some of the winter months. The long-term consequences are unpredictable, but since both ocean current and air movement are driven by the difference between equatorial and polar temperatures, dramatic climate change is likely to follow.

“The trajectory is towards becoming ice-free in the summer, but there is uncertainty as to when that is going to occur,” Dr Screen said.

“You can hedge your bets. The shift in the IPO means there’s more chance of it being on the earlier end of that window than the later end.” – Climate News Network

Food supply falls as fish flee warmer seas

On the fishing grounds, they already know about global warming. As fish flee warmer seas there are winners – but many more losers.

LONDON, 4 March 2019 – Global warming has already begun to affect fishing worldwide as fish flee warmer seas, a new study says.

In the last 80 years, there has been an estimated drop of more than 4% in sustainable catches for many kinds of fish and shellfish. That is the average. In some regions – the East China Sea, for instance, and Europe’s North Sea –  the estimated decline was between 15% and 35%.

In the course of the last century, global average temperatures have crept up by about 1°C above the average for most of human history, as a reaction to the unconstrained burning of fossil fuels. If the world continues to burn ever-greater volumes of coal, oil and natural gas, it could be 3°C warmer or more by the end of the century.

Last year was only the fourth warmest for air surface temperatures, but the warmest since records began for the world’s oceans.

“Fisheries around the world have already responded to global warming. These aren’t hypothetical changes some time in the future”

US researchers report in the journal Science that they looked at the impact of ocean warming in 235 populations of 124 species of fish, crustaceans and molluscs in 38 ecological regions between the years 1930 and 2010.

They then matched the world data on fish catches with ocean temperature maps to estimate what warming has done to the sustainable catch – that is, the biggest haul fishing crews can make without reducing breeding stocks for the seasons to follow.

“We were stunned to find that fisheries around the world have already responded to global warming,” said Malin Pinsky of Rutgers University, and one of the authors. “These aren’t hypothetical changes some time in the future.”

The researchers found that some species in some climate zones actually benefited from warming, and fish with faster life cycles sometimes responded well, sometimes badly to the temperature changes. Some responded by shifting their geographical range.

More climate losers

But overall, said Christopher Free, once of Rutgers and now at the University of California, Santa Barbara, “among the populations we studied, the climate losers outweigh the climate winners.”

And his colleague Olaf Jensen, also from Rutgers, said: “Fish populations can only tolerate so much warning, though. Many of the species that have benefited from warming so far are likely to start declining as temperatures continue to rise.”

Fishermen off the coasts of Labrador and Newfoundland, in the Baltic, the Indian Ocean and the northeast US shelf may have seen more productive hauls of fish. But the biggest losses were in the Sea of Japan, the North Sea, off the Iberian coast and the Celtic-Biscay shelf.

Many fish species are adapted to a precise range of temperatures: they flourish not just in specific marine ecosystems but in thermal niches as well. Once things begin to change, they swim away or perish.

Marauding invaders

Fishermen in the North Atlantic have repeatedly observed changes in the available catch, as the cod shift north and the sardines migrate from increasingly uncomfortable warm waters. Warming in Mediterranean waters creates enticing conditions for invaders from the Red Sea and further south, at huge cost to the resident species.

The lesson is that fish stocks must be carefully conserved, and ocean reserves protected. Researchers have consistently warned that global warming and climate change – especially when combined with changes in ocean water chemistry as a consequence of carbon dioxide build-up in the atmosphere – could soon start to constrain an important source of nutrition: an estimated 3.2 billion people rely on the sea for an estimated 20% of their animal protein, especially in East Asia.

“This means 15% to 35% less fish available for food and employment in a region with some of the fastest-growing human populations in the world,” said Dr Free.

“Knowing exactly how fisheries will change under future warming is challenging, but we do know that failing to adapt to changing fisheries productivity will result in less food and fewer profits relative to today.” – Climate News Network

On the fishing grounds, they already know about global warming. As fish flee warmer seas there are winners – but many more losers.

LONDON, 4 March 2019 – Global warming has already begun to affect fishing worldwide as fish flee warmer seas, a new study says.

In the last 80 years, there has been an estimated drop of more than 4% in sustainable catches for many kinds of fish and shellfish. That is the average. In some regions – the East China Sea, for instance, and Europe’s North Sea –  the estimated decline was between 15% and 35%.

In the course of the last century, global average temperatures have crept up by about 1°C above the average for most of human history, as a reaction to the unconstrained burning of fossil fuels. If the world continues to burn ever-greater volumes of coal, oil and natural gas, it could be 3°C warmer or more by the end of the century.

Last year was only the fourth warmest for air surface temperatures, but the warmest since records began for the world’s oceans.

“Fisheries around the world have already responded to global warming. These aren’t hypothetical changes some time in the future”

US researchers report in the journal Science that they looked at the impact of ocean warming in 235 populations of 124 species of fish, crustaceans and molluscs in 38 ecological regions between the years 1930 and 2010.

They then matched the world data on fish catches with ocean temperature maps to estimate what warming has done to the sustainable catch – that is, the biggest haul fishing crews can make without reducing breeding stocks for the seasons to follow.

“We were stunned to find that fisheries around the world have already responded to global warming,” said Malin Pinsky of Rutgers University, and one of the authors. “These aren’t hypothetical changes some time in the future.”

The researchers found that some species in some climate zones actually benefited from warming, and fish with faster life cycles sometimes responded well, sometimes badly to the temperature changes. Some responded by shifting their geographical range.

More climate losers

But overall, said Christopher Free, once of Rutgers and now at the University of California, Santa Barbara, “among the populations we studied, the climate losers outweigh the climate winners.”

And his colleague Olaf Jensen, also from Rutgers, said: “Fish populations can only tolerate so much warning, though. Many of the species that have benefited from warming so far are likely to start declining as temperatures continue to rise.”

Fishermen off the coasts of Labrador and Newfoundland, in the Baltic, the Indian Ocean and the northeast US shelf may have seen more productive hauls of fish. But the biggest losses were in the Sea of Japan, the North Sea, off the Iberian coast and the Celtic-Biscay shelf.

Many fish species are adapted to a precise range of temperatures: they flourish not just in specific marine ecosystems but in thermal niches as well. Once things begin to change, they swim away or perish.

Marauding invaders

Fishermen in the North Atlantic have repeatedly observed changes in the available catch, as the cod shift north and the sardines migrate from increasingly uncomfortable warm waters. Warming in Mediterranean waters creates enticing conditions for invaders from the Red Sea and further south, at huge cost to the resident species.

The lesson is that fish stocks must be carefully conserved, and ocean reserves protected. Researchers have consistently warned that global warming and climate change – especially when combined with changes in ocean water chemistry as a consequence of carbon dioxide build-up in the atmosphere – could soon start to constrain an important source of nutrition: an estimated 3.2 billion people rely on the sea for an estimated 20% of their animal protein, especially in East Asia.

“This means 15% to 35% less fish available for food and employment in a region with some of the fastest-growing human populations in the world,” said Dr Free.

“Knowing exactly how fisheries will change under future warming is challenging, but we do know that failing to adapt to changing fisheries productivity will result in less food and fewer profits relative to today.” – Climate News Network

Carbon rise could cause cloud tipping point

The planet’s temperature could zoom in an ever more greenhouse world, as researchers identify a dangerous possible cloud tipping point.

LONDON, 27 February, 2019 − Climate scientists have confirmed a high-level hazard, a cloud tipping point, that could send global warming into a dramatic upwards spiral.

If carbon dioxide concentrations in the atmosphere become high enough, the clouds that shade and cool some of the tropical and subtropical oceans could become unstable and disperse. More radiation would slam into the ocean and the coasts, and surface temperatures could soar as high as 8°C above the levels for most of human history.

And this dramatic spike would be independent of any warming directly linked to the steady rise in carbon dioxide concentrations themselves, the scientists warn.

In Paris in 2015, a total of 195 nations vowed to take steps to contain global warming to “well below” a maximum of 2°C above the average before the start of the Industrial Revolution, powered by the exploitation of fossil fuels.

In the last 200 years, levels of the greenhouse gas carbon dioxide in the atmosphere have increased from 288 parts per million to around 410 ppm and the average global temperature has already increased by about 1°C.

“Our results show that there are dangerous climate change thresholds that we have been unaware of”

Researchers have repeatedly warned that the Paris promises have yet to be turned into coherent and consistent action, and that if the world goes on burning coal, oil and natural gas on a “business as usual” scenario, catastrophic consequences could follow.

Now US researchers warn in the journal Nature Geoscience that they know a bit more about the climate mechanisms by which global warming could accelerate.

If carbon dioxide ratios climb to 1,200 ppm – and without drastic action this could happen in the next century – then the Earth could reach a tipping point, and the marine stratus clouds that shade one-fifth of the low-latitude oceans and reflect between 30% and 60% of shortwave radiation back into space could break up and scatter.

The sunlight they normally block would slam into the deep blue sea, to warm the planet even faster.

Avoidance possible

“I think and hope that technological changes will slow carbon emissions so that we do not actually reach such high CO2 concentrations,” said Tapio Schneider, an environmental scientist at the Jet Propulsion Laboratory, the research centre managed for the US space agency NASA by the California Institute of Technology.

“But our results show that there are dangerous climate change thresholds that we have been unaware of.”

The role of clouds in the intricate interplay of sunlight, forests, oceans, rocks and atmosphere that controls the planet’s climate has been the subject of argument. Do clouds really slow warming? And if so, by how much, and under what conditions?

There may not be a simple answer, although researchers are fairly confident that the thinning of clouds over the California coasts may have made calamitous wildfires in the state more probable.

So to resolve what Professor Schneider calls “a blind spot” in climate modelling, he and his colleagues worked on a small-scale computer simulation of one representative section of the atmosphere above the subtropical ocean, and then used supercomputers to model the clouds and their turbulent movement over a mathematical representation of the sea. And then they started to tune up the atmospheric concentrations of carbon dioxide.

Carbon threshold

They found that, once CO2 levels reached 1,200 ppm, the decks of stratocumulus cloud vanished, and did not reappear until CO2 levels dropped to well below this dangerous threshold.

If – and this has yet to happen – other researchers use different approaches to confirm the result, then the US scientists will have established a better understanding of one component of natural climate control.

The research may also illuminate a puzzle of climate history: 50 million or more years ago, during a geological epoch called the Eocene, the Arctic ice cap melted. Climate models have shown that, for this to happen, atmospheric carbon ratios would need to rise to 4,000 ppm.

These, the Caltech team, suggests, would be “implausibly high” CO2 levels. The latest study suggests this might be an overestimate: a mere 1,200 ppm would be enough to set the planetary thermometer soaring. − Climate News Network

The planet’s temperature could zoom in an ever more greenhouse world, as researchers identify a dangerous possible cloud tipping point.

LONDON, 27 February, 2019 − Climate scientists have confirmed a high-level hazard, a cloud tipping point, that could send global warming into a dramatic upwards spiral.

If carbon dioxide concentrations in the atmosphere become high enough, the clouds that shade and cool some of the tropical and subtropical oceans could become unstable and disperse. More radiation would slam into the ocean and the coasts, and surface temperatures could soar as high as 8°C above the levels for most of human history.

And this dramatic spike would be independent of any warming directly linked to the steady rise in carbon dioxide concentrations themselves, the scientists warn.

In Paris in 2015, a total of 195 nations vowed to take steps to contain global warming to “well below” a maximum of 2°C above the average before the start of the Industrial Revolution, powered by the exploitation of fossil fuels.

In the last 200 years, levels of the greenhouse gas carbon dioxide in the atmosphere have increased from 288 parts per million to around 410 ppm and the average global temperature has already increased by about 1°C.

“Our results show that there are dangerous climate change thresholds that we have been unaware of”

Researchers have repeatedly warned that the Paris promises have yet to be turned into coherent and consistent action, and that if the world goes on burning coal, oil and natural gas on a “business as usual” scenario, catastrophic consequences could follow.

Now US researchers warn in the journal Nature Geoscience that they know a bit more about the climate mechanisms by which global warming could accelerate.

If carbon dioxide ratios climb to 1,200 ppm – and without drastic action this could happen in the next century – then the Earth could reach a tipping point, and the marine stratus clouds that shade one-fifth of the low-latitude oceans and reflect between 30% and 60% of shortwave radiation back into space could break up and scatter.

The sunlight they normally block would slam into the deep blue sea, to warm the planet even faster.

Avoidance possible

“I think and hope that technological changes will slow carbon emissions so that we do not actually reach such high CO2 concentrations,” said Tapio Schneider, an environmental scientist at the Jet Propulsion Laboratory, the research centre managed for the US space agency NASA by the California Institute of Technology.

“But our results show that there are dangerous climate change thresholds that we have been unaware of.”

The role of clouds in the intricate interplay of sunlight, forests, oceans, rocks and atmosphere that controls the planet’s climate has been the subject of argument. Do clouds really slow warming? And if so, by how much, and under what conditions?

There may not be a simple answer, although researchers are fairly confident that the thinning of clouds over the California coasts may have made calamitous wildfires in the state more probable.

So to resolve what Professor Schneider calls “a blind spot” in climate modelling, he and his colleagues worked on a small-scale computer simulation of one representative section of the atmosphere above the subtropical ocean, and then used supercomputers to model the clouds and their turbulent movement over a mathematical representation of the sea. And then they started to tune up the atmospheric concentrations of carbon dioxide.

Carbon threshold

They found that, once CO2 levels reached 1,200 ppm, the decks of stratocumulus cloud vanished, and did not reappear until CO2 levels dropped to well below this dangerous threshold.

If – and this has yet to happen – other researchers use different approaches to confirm the result, then the US scientists will have established a better understanding of one component of natural climate control.

The research may also illuminate a puzzle of climate history: 50 million or more years ago, during a geological epoch called the Eocene, the Arctic ice cap melted. Climate models have shown that, for this to happen, atmospheric carbon ratios would need to rise to 4,000 ppm.

These, the Caltech team, suggests, would be “implausibly high” CO2 levels. The latest study suggests this might be an overestimate: a mere 1,200 ppm would be enough to set the planetary thermometer soaring. − Climate News Network