Tag Archives: Warming

Northern Europe’s warm water flow may falter

Global heating can stop the flow of Europe’s warm water from the tropics. Happening often during the Ice Ages, it could soon recur.

LONDON, 1 April, 2020 – Oceanographers have confirmed once again that global heating could slow or shut down the flow of currents such as the Gulf Stream, ending northern Europe’s warm water supply with an unexpected and prolonged cold snap.

This time the confidence is based neither on ocean measurements made now, nor complex computer simulations of the future. There is fresh evidence from the sea floor that such an ocean shutdown happened many times in the last half a million years of Ice Ages.

The Gulf Stream is part of a much larger flow of water called the Atlantic Meridional Overturning Circulation, an ocean recycling system that both nourishes marine life and moderates the climate in two hemispheres.

For the last 10,000 years of human history, tropical water has flowed north from the Caribbean and equatorial regions and washed the shores of Europe as far north as Norway, bringing equatorial heat to soften the impact of European winters.

A former UK chief scientist once calculated that the Gulf Stream delivered the warmth of 27,000 power stations and kept Britain about 5°C warmer than its citizens had any right to expect, given the latitude at which they lived.

“These findings suggest that our climate system, which depends greatly on deep ocean circulation, is critically poised near a tipping point for abrupt disruptions”

But as that stretch of the Gulf Stream known to oceanographers as the North Atlantic drift current reaches the Greenland Sea it becomes increasingly colder and saltier and thus more dense, and sinks to the ocean floor, loaded with dissolved atmospheric carbon dioxide and oxygen, to become a southward flow called the North Atlantic Deepwater formation.

And it also mingles with fresh water melting each summer from the Greenland ice sheet. But as the rate of Arctic melting accelerates, more fresh water will plunge into the same sea, with an increasing probability that it will disrupt the ocean cycle, turn off the flow of warm tropical water, and plunge Europe into a prolonged cold spell.

In its most dramatic form, this hypothesis was the basis for a 2004 Hollywood disaster movie called The Day After Tomorrow. Climate scientists are fairly sure that such an event would not mean the sudden advance of glacial ice over much of Europe and North America. But they have repeatedly identified evidence that the flow of the northward current is beginning to weaken.

And the journal Science now carries additional evidence that the ocean circulation was repeatedly interrupted for periods of a century or more during the warm spells or interglacials that have happened during the last 450,000 years.

Shells’ signatures

The signature of ocean change is there in the tiny sea shells from marine creatures called foraminifera that rain down onto the ocean floor to form annual layers of silent testimony to past climates.

When the mix of carbon isotope ratios preserved in them is high, that is a sign that the Atlantic circulation was once vigorous. When it is low, then this overturning circulation is feeble, or has stopped altogether.

The signal from the deep ocean is that when they happen, these disruptions seem to happen very swiftly, and to linger for 100 years or more. And, the scientists say, these interruptions in the flow of the ocean – and with it, the transport of heat from the tropics – happen more easily than previously appreciated, and they occurred in past climate conditions similar to those the world may soon face.

“These findings suggest that our climate system, which depends greatly on deep ocean circulation, is critically poised near a tipping point for abrupt disruptions,” said Yair Rosenthal of Rutgers University in the US, one of the authors.

“Although the disruptions in circulation and possible coolings may be relatively short-lived – lasting maybe a century or more – the consequences might be large.” – Climate News Network

Global heating can stop the flow of Europe’s warm water from the tropics. Happening often during the Ice Ages, it could soon recur.

LONDON, 1 April, 2020 – Oceanographers have confirmed once again that global heating could slow or shut down the flow of currents such as the Gulf Stream, ending northern Europe’s warm water supply with an unexpected and prolonged cold snap.

This time the confidence is based neither on ocean measurements made now, nor complex computer simulations of the future. There is fresh evidence from the sea floor that such an ocean shutdown happened many times in the last half a million years of Ice Ages.

The Gulf Stream is part of a much larger flow of water called the Atlantic Meridional Overturning Circulation, an ocean recycling system that both nourishes marine life and moderates the climate in two hemispheres.

For the last 10,000 years of human history, tropical water has flowed north from the Caribbean and equatorial regions and washed the shores of Europe as far north as Norway, bringing equatorial heat to soften the impact of European winters.

A former UK chief scientist once calculated that the Gulf Stream delivered the warmth of 27,000 power stations and kept Britain about 5°C warmer than its citizens had any right to expect, given the latitude at which they lived.

“These findings suggest that our climate system, which depends greatly on deep ocean circulation, is critically poised near a tipping point for abrupt disruptions”

But as that stretch of the Gulf Stream known to oceanographers as the North Atlantic drift current reaches the Greenland Sea it becomes increasingly colder and saltier and thus more dense, and sinks to the ocean floor, loaded with dissolved atmospheric carbon dioxide and oxygen, to become a southward flow called the North Atlantic Deepwater formation.

And it also mingles with fresh water melting each summer from the Greenland ice sheet. But as the rate of Arctic melting accelerates, more fresh water will plunge into the same sea, with an increasing probability that it will disrupt the ocean cycle, turn off the flow of warm tropical water, and plunge Europe into a prolonged cold spell.

In its most dramatic form, this hypothesis was the basis for a 2004 Hollywood disaster movie called The Day After Tomorrow. Climate scientists are fairly sure that such an event would not mean the sudden advance of glacial ice over much of Europe and North America. But they have repeatedly identified evidence that the flow of the northward current is beginning to weaken.

And the journal Science now carries additional evidence that the ocean circulation was repeatedly interrupted for periods of a century or more during the warm spells or interglacials that have happened during the last 450,000 years.

Shells’ signatures

The signature of ocean change is there in the tiny sea shells from marine creatures called foraminifera that rain down onto the ocean floor to form annual layers of silent testimony to past climates.

When the mix of carbon isotope ratios preserved in them is high, that is a sign that the Atlantic circulation was once vigorous. When it is low, then this overturning circulation is feeble, or has stopped altogether.

The signal from the deep ocean is that when they happen, these disruptions seem to happen very swiftly, and to linger for 100 years or more. And, the scientists say, these interruptions in the flow of the ocean – and with it, the transport of heat from the tropics – happen more easily than previously appreciated, and they occurred in past climate conditions similar to those the world may soon face.

“These findings suggest that our climate system, which depends greatly on deep ocean circulation, is critically poised near a tipping point for abrupt disruptions,” said Yair Rosenthal of Rutgers University in the US, one of the authors.

“Although the disruptions in circulation and possible coolings may be relatively short-lived – lasting maybe a century or more – the consequences might be large.” – Climate News Network

A second US Dust Bowl would hit world food stocks

When the US Great Plains are hit again by sustained drought, the world’s food stocks will feel the heat.

LONDON, 27 March, 2020 – The next time the fertile soils of North America turn to dust, the consequences will hit food stocks worldwide.

Within four years of a climate crisis of the kind that fired John Steinbeck’s 1939 masterpiece The Grapes of Wrath, the US would have consumed almost all its grain reserves.

And the ripple effects would be felt in all those countries to which America normally exports grain. That is because America feeds much of the world: in a good year, the US exports wheat with an energy value of more than 90 trillion kilocalories. The collapse of farmland into wasteland on the scale that inspired John Steinbeck could reduce this over a four-year period to around 50 trillion kcal.

Worldwide, global wheat reserves would fall by 31% in the first year, and four years on somewhere between 36 and 52 countries would have consumed three-fourths of their own reserves. Food prices would rise around the planet.

“In today’s system of global food trade, disruptions are not bound by borders. Shocks to production are expected to affect trade partners who depend on imports for their domestic food supply,” said Alison Heslin, a climate scientist at Columbia University in the US.

“Accessing food reserves can, for a time, buffer populations from trade-induced supply shortages, but as reserves deplete, people are at risk of food shortages”

“Our results remind us that mitigating climate risks requires accounting not only for the direct effects of climate change, like local extreme weather events, but also the climate impacts which travel through our interconnected system of global trade.”

By some time in the mid-century, most of the US will be between 1.5°C to 2°C warmer. Researchers have already warned that the border between the arid western states and the more fertile mid-western plains has shifted to the east.

There have been repeated warnings that as global average temperatures rise, in response to ever greater use of fossil fuels, the US will become increasingly vulnerable to climate extremes, including megadroughts. Drought is already becoming the “new normal” for Californians, and the fertility of the Great Plains is in any case vulnerable to human changes to a natural landscape.

A succession of droughts of the kind that turned the farmland of Kansas and Oklahoma into a devastated landscape, and turned thousands of Americans into climate refugees, would not necessarily now mean the onset of regional famine.

Dr Heslin and her colleagues report in the journal Frontiers in Sustainable Food Systems that they contemplated the likelihood of a four-year drought of the kind that created the notorious 1930s Dust Bowl, and then examined the possible impact on world trade systems.

Yields and nutrition affected

Just one such climate event could hit hard those nations that rely on food imports, but even the other great grain-producing countries – among them China, India, Iran, Canada, Russia, Morocco, Australia and Egypt – would see their reserves fall.

The climate crisis is in any case a threat to the world’s supper tables. There has been repeated evidence that food output will inevitably be at risk in a warming world. With higher temperatures, yields will be reduced and with higher atmospheric levels of carbon dioxide that warm the planet, nutrition levels of many staples are expected to fall.

The researchers factored in none of these things. They supposed that a climate catastrophe that paralleled the Dust Bowl era would occur only in the US, and found that, despite strain, the world’s markets could probably cope.

But other studies have repeatedly found that the potential for climate catastrophe and massive crop failure to strike in more than one region at any one time are increasing, with ominous consequences for world food security.

“In the context of food security, we show that accessing food reserves can, for a time, buffer populations from trade-induced supply shortages,” said Dr Heslin, “but as reserves deplete, people are at risk of food shortages.” – Climate News Network

When the US Great Plains are hit again by sustained drought, the world’s food stocks will feel the heat.

LONDON, 27 March, 2020 – The next time the fertile soils of North America turn to dust, the consequences will hit food stocks worldwide.

Within four years of a climate crisis of the kind that fired John Steinbeck’s 1939 masterpiece The Grapes of Wrath, the US would have consumed almost all its grain reserves.

And the ripple effects would be felt in all those countries to which America normally exports grain. That is because America feeds much of the world: in a good year, the US exports wheat with an energy value of more than 90 trillion kilocalories. The collapse of farmland into wasteland on the scale that inspired John Steinbeck could reduce this over a four-year period to around 50 trillion kcal.

Worldwide, global wheat reserves would fall by 31% in the first year, and four years on somewhere between 36 and 52 countries would have consumed three-fourths of their own reserves. Food prices would rise around the planet.

“In today’s system of global food trade, disruptions are not bound by borders. Shocks to production are expected to affect trade partners who depend on imports for their domestic food supply,” said Alison Heslin, a climate scientist at Columbia University in the US.

“Accessing food reserves can, for a time, buffer populations from trade-induced supply shortages, but as reserves deplete, people are at risk of food shortages”

“Our results remind us that mitigating climate risks requires accounting not only for the direct effects of climate change, like local extreme weather events, but also the climate impacts which travel through our interconnected system of global trade.”

By some time in the mid-century, most of the US will be between 1.5°C to 2°C warmer. Researchers have already warned that the border between the arid western states and the more fertile mid-western plains has shifted to the east.

There have been repeated warnings that as global average temperatures rise, in response to ever greater use of fossil fuels, the US will become increasingly vulnerable to climate extremes, including megadroughts. Drought is already becoming the “new normal” for Californians, and the fertility of the Great Plains is in any case vulnerable to human changes to a natural landscape.

A succession of droughts of the kind that turned the farmland of Kansas and Oklahoma into a devastated landscape, and turned thousands of Americans into climate refugees, would not necessarily now mean the onset of regional famine.

Dr Heslin and her colleagues report in the journal Frontiers in Sustainable Food Systems that they contemplated the likelihood of a four-year drought of the kind that created the notorious 1930s Dust Bowl, and then examined the possible impact on world trade systems.

Yields and nutrition affected

Just one such climate event could hit hard those nations that rely on food imports, but even the other great grain-producing countries – among them China, India, Iran, Canada, Russia, Morocco, Australia and Egypt – would see their reserves fall.

The climate crisis is in any case a threat to the world’s supper tables. There has been repeated evidence that food output will inevitably be at risk in a warming world. With higher temperatures, yields will be reduced and with higher atmospheric levels of carbon dioxide that warm the planet, nutrition levels of many staples are expected to fall.

The researchers factored in none of these things. They supposed that a climate catastrophe that paralleled the Dust Bowl era would occur only in the US, and found that, despite strain, the world’s markets could probably cope.

But other studies have repeatedly found that the potential for climate catastrophe and massive crop failure to strike in more than one region at any one time are increasing, with ominous consequences for world food security.

“In the context of food security, we show that accessing food reserves can, for a time, buffer populations from trade-induced supply shortages,” said Dr Heslin, “but as reserves deplete, people are at risk of food shortages.” – Climate News Network

Vegetation holds key to climate control

New studies shine a light on the intricate relationship in which climate affects vegetation, which in turn impacts on the global climate.

LONDON, 23 March, 2020 − Here’s an easy way to warm the tropics even further: just fell some rainforest, and the local temperatures will soar by at least a degree Celsius, showing the role played by vegetation.

There is also a good way to temper the summer heat of temperate Europe: just abandon some farmland, leave it to go wild and leafy, and the thermometer will drop by perhaps as much as 1°C.

And, paradoxically, there is even a leafy way to warm the Arctic: burn lots of fossil fuels, precipitate a climate crisis, advance the growth of spring foliage by three weeks or so, and check the thermometer. The region will be even warmer, just because the Arctic has become greener.

These apparently contradictory findings are, more than anything else, a reminder that the pas de deux of vegetation and atmosphere is complex, intricate and finely balanced. Nor are they inconsistent, as each study simply takes the measure of vegetation change on local or regional climate.

Reducing heating

In sum, and for the time being, the big picture remains that forests absorb carbon, and more vigorous growth absorbs more carbon to significantly reduce the average rates of global heating across the entire planet.

In effect, all three studies demonstrate that vegetation moderates extremes of temperature in three climate zones.

Brazilian scientists report in the Public Library of Science journal
PLOS One that they subdivided a tract of the Atlantic rainforest in the southeast of the nation into 120-metre squares, measured those segments that had been part-felled or clear-felled, and read the local land surface temperatures.

If even one fourth of a hectare had been cleared, the local temperature went up by 1°C. If the entire hectare had been razed, the rise could be as high as 4°C.

Risk to trees

The Atlantic rainforest is one of the world’s richest ecosystems: it covers 15% of Brazil, but 72% of the population lives there. It holds seven of Brazil’s nine largest drainage basins, delivers water to 130 million people and its dams provide 60% of the nation’s hydroelectric power.

Between 2017 and 2018, around 113 square kilometres of this forest was cleared. As temperatures continue to rise, some tree species could be at risk.

“We don’t have enough data to predict how long it will take, but in the long run, rising temperatures in Atlantic rainforest fragments could certainly influence the survival of tree species in the forest, albeit some species more than others,” says one of the report’s authors, Carlos Joly, professor of plant biology at the University of Campinas in Brazil.

“The forest is extremely important to maintaining milder temperatures on the local and regional scale. Changes in its function could disrupt this type of ecosystem service.

“Abandoned cropland – or land cover change more generally – and its role in regional climate can help us adapt to and mitigate the effects of climate change”

“The Atlantic rainforest doesn’t produce water but it protects the springs and permits the storage of water in reservoirs for consumption, power generation, agricultural irrigation and fishing, among other activities.”

By contrast, Europeans have achieved a local 1°C cooling simply by abandoning farmland that was no longer sufficiently productive.

Between 1992 and 2014, the European Space Agency satellites compiled detailed maps of the continents, measuring the extents of evergreen needle-leaf forest, deciduous broadleaf woodland, open shrubland, crop fields, urban and built-up areas, wetlands, peatlands, grassland and mosaic areas of crops and wilderness.

In those 24 years – partly because of dramatic political changes that followed the collapse of the Soviet Union – around 25 million hectares of farmland was abandoned.

Drying wetlands

Although farmland was colonised elsewhere, the continent was left with 5 million hectares – an area the size of Switzerland – to be colonised by trees and other natural foliage, European scientists report in the journal Nature Communications.

Overall, the loss of cropland in Western Europe was associated with a drop of 1° in spring and summer. In eastern and northeastern Europe, however, temperatures rose by as much as 1°C, partly because what had once been wetlands began to dry.

“We are already at a mean warming of about 1.8°C on the land, and we will be about 3°C on the land even if we are successful at stabilising the average global temperature at 1.5°C,” says one of the report’s authors, Francesco Cherubini, director of the Industrial Ecology Programme at the Norwegian University of Science and Technology.

“That means we take action to adapt to a warming climate, and land use planning is one action that can bring local cooling benefits.”

The Arctic greens

“The message is quite clear. Abandoned cropland – or land cover change more generally – and its role in regional climate can help us adapt to and mitigate the effects of climate change. And by improving agricultural systems, we can free up land for multiple uses.”

But while Europe is changing, and forest in the tropics is being lost, the Arctic is becoming greener: as temperatures rise, vegetation has moved northwards and spring has arrived ever earlier, and growing seasons have lasted longer.

The science of measurement of seasonal change in plant and animal behaviour is called phenology. Chinese and US scientists report in Nature Climate Change that they looked at computer models of vegetation change and factored in the numbers: on average, in the last four decades, leaf-out has advanced by an average of more than four days a decade, and in some cases up to 12 days a decade.

That means snow-covered ground has retreated, and green leaves have moved northwards, and become denser.

Climate feedback

Snow reflects solar radiation, and darker colours absorb it. That means that local landscapes in the north have tended to become even warmer with each decade.

In the Canadian archipelago, the air has been measured at 0.7°C warmer, and parts of Siberia and the Tibetan plateau − far from any leafy canopy − have warmed by 0.4°C and 0.3°C respectively because advanced leaf-out further south means more water vapour, which moves north to change patterns of cloud cover and snowfall.

Climate scientists see this as positive feedback: climate change begets even faster climate change. Global heating tends to accelerate. Climate change affects vegetation, which in turn affects climate yet further.

“Positive feedback loops between climate and spring leaf phenology is likely to amplify in the northern high latitudes,” says Gensuo Jia, one of the researchers from the Chinese Academy of Sciences. “The impact of vegetation change on climate is profound in spring.” − Climate News Network

New studies shine a light on the intricate relationship in which climate affects vegetation, which in turn impacts on the global climate.

LONDON, 23 March, 2020 − Here’s an easy way to warm the tropics even further: just fell some rainforest, and the local temperatures will soar by at least a degree Celsius, showing the role played by vegetation.

There is also a good way to temper the summer heat of temperate Europe: just abandon some farmland, leave it to go wild and leafy, and the thermometer will drop by perhaps as much as 1°C.

And, paradoxically, there is even a leafy way to warm the Arctic: burn lots of fossil fuels, precipitate a climate crisis, advance the growth of spring foliage by three weeks or so, and check the thermometer. The region will be even warmer, just because the Arctic has become greener.

These apparently contradictory findings are, more than anything else, a reminder that the pas de deux of vegetation and atmosphere is complex, intricate and finely balanced. Nor are they inconsistent, as each study simply takes the measure of vegetation change on local or regional climate.

Reducing heating

In sum, and for the time being, the big picture remains that forests absorb carbon, and more vigorous growth absorbs more carbon to significantly reduce the average rates of global heating across the entire planet.

In effect, all three studies demonstrate that vegetation moderates extremes of temperature in three climate zones.

Brazilian scientists report in the Public Library of Science journal
PLOS One that they subdivided a tract of the Atlantic rainforest in the southeast of the nation into 120-metre squares, measured those segments that had been part-felled or clear-felled, and read the local land surface temperatures.

If even one fourth of a hectare had been cleared, the local temperature went up by 1°C. If the entire hectare had been razed, the rise could be as high as 4°C.

Risk to trees

The Atlantic rainforest is one of the world’s richest ecosystems: it covers 15% of Brazil, but 72% of the population lives there. It holds seven of Brazil’s nine largest drainage basins, delivers water to 130 million people and its dams provide 60% of the nation’s hydroelectric power.

Between 2017 and 2018, around 113 square kilometres of this forest was cleared. As temperatures continue to rise, some tree species could be at risk.

“We don’t have enough data to predict how long it will take, but in the long run, rising temperatures in Atlantic rainforest fragments could certainly influence the survival of tree species in the forest, albeit some species more than others,” says one of the report’s authors, Carlos Joly, professor of plant biology at the University of Campinas in Brazil.

“The forest is extremely important to maintaining milder temperatures on the local and regional scale. Changes in its function could disrupt this type of ecosystem service.

“Abandoned cropland – or land cover change more generally – and its role in regional climate can help us adapt to and mitigate the effects of climate change”

“The Atlantic rainforest doesn’t produce water but it protects the springs and permits the storage of water in reservoirs for consumption, power generation, agricultural irrigation and fishing, among other activities.”

By contrast, Europeans have achieved a local 1°C cooling simply by abandoning farmland that was no longer sufficiently productive.

Between 1992 and 2014, the European Space Agency satellites compiled detailed maps of the continents, measuring the extents of evergreen needle-leaf forest, deciduous broadleaf woodland, open shrubland, crop fields, urban and built-up areas, wetlands, peatlands, grassland and mosaic areas of crops and wilderness.

In those 24 years – partly because of dramatic political changes that followed the collapse of the Soviet Union – around 25 million hectares of farmland was abandoned.

Drying wetlands

Although farmland was colonised elsewhere, the continent was left with 5 million hectares – an area the size of Switzerland – to be colonised by trees and other natural foliage, European scientists report in the journal Nature Communications.

Overall, the loss of cropland in Western Europe was associated with a drop of 1° in spring and summer. In eastern and northeastern Europe, however, temperatures rose by as much as 1°C, partly because what had once been wetlands began to dry.

“We are already at a mean warming of about 1.8°C on the land, and we will be about 3°C on the land even if we are successful at stabilising the average global temperature at 1.5°C,” says one of the report’s authors, Francesco Cherubini, director of the Industrial Ecology Programme at the Norwegian University of Science and Technology.

“That means we take action to adapt to a warming climate, and land use planning is one action that can bring local cooling benefits.”

The Arctic greens

“The message is quite clear. Abandoned cropland – or land cover change more generally – and its role in regional climate can help us adapt to and mitigate the effects of climate change. And by improving agricultural systems, we can free up land for multiple uses.”

But while Europe is changing, and forest in the tropics is being lost, the Arctic is becoming greener: as temperatures rise, vegetation has moved northwards and spring has arrived ever earlier, and growing seasons have lasted longer.

The science of measurement of seasonal change in plant and animal behaviour is called phenology. Chinese and US scientists report in Nature Climate Change that they looked at computer models of vegetation change and factored in the numbers: on average, in the last four decades, leaf-out has advanced by an average of more than four days a decade, and in some cases up to 12 days a decade.

That means snow-covered ground has retreated, and green leaves have moved northwards, and become denser.

Climate feedback

Snow reflects solar radiation, and darker colours absorb it. That means that local landscapes in the north have tended to become even warmer with each decade.

In the Canadian archipelago, the air has been measured at 0.7°C warmer, and parts of Siberia and the Tibetan plateau − far from any leafy canopy − have warmed by 0.4°C and 0.3°C respectively because advanced leaf-out further south means more water vapour, which moves north to change patterns of cloud cover and snowfall.

Climate scientists see this as positive feedback: climate change begets even faster climate change. Global heating tends to accelerate. Climate change affects vegetation, which in turn affects climate yet further.

“Positive feedback loops between climate and spring leaf phenology is likely to amplify in the northern high latitudes,” says Gensuo Jia, one of the researchers from the Chinese Academy of Sciences. “The impact of vegetation change on climate is profound in spring.” − Climate News Network

Record Antarctic temperatures fuel sea level worry


Sea levels may threaten coastal cities sooner than expected, scientists say, as ice loss speeds up and Antarctic temperatures rise.

LONDON, 20 February, 2020 − Across the world, people now alive in coastal areas may face dangerously rising seas within their lifetimes, as record Antarctic temperatures and rapid melting of the continent’s ice drive global sea levels upwards.

Temperatures on the Antarctic Peninsula reached more than 20°C for the first time in history earlier this month, the Guardian reported: “The 20.75C logged by Brazilian scientists at Seymour Island on 9 February was almost a full degree higher than the previous record of 19.8C, taken on Signy Island in January 1982.”

The Antarctic Peninsula has warmed by almost 3°C since the start of the Industrial Revolution around 200 years ago − faster than almost anywhere else on Earth. But scientists are increasingly concerned not only about the Peninsula, but with the possibility that the entire southern continent may be heating up much faster than current estimates suggest.

Among evidence of increasing scientific effort to determine what is happening is a joint UK-US collaboration, due to report in 2023 on the chances of the collapse of the huge Thwaites glacier in West Antarctica, where from 1992 to 2017 the annual rate of ice loss rose threefold.

Big speed-up

Now a study by scientists co-ordinated by Germany’s Potsdam Institute for Climate Impact Research (PIK) says sea level rise caused by Antarctica’s ice loss could become a major risk for coastal protection in the near future.

After what they call “an exceptionally comprehensive comparison of state-of-the-art computer models from around the world”, they conclude that Antarctica alone could cause global sea level to rise by 2100 by up to three times more than it did in the last century.

“The ‘Antarctica Factor’ turns out to be the greatest risk, and also the greatest uncertainty, for sea levels around the globe,” says the lead author, Anders Levermann of PIK and Columbia University’s Lamont-Doherty Earth Observatory (LDEO) in New York.

“While we saw about 19 centimetres of sea level rise in the past 100 years, Antarctic ice loss could lead to up to 58 centimetres within this century”, he said.

“We know for certain that not stopping the burning of coal, oil and gas will drive up the risks for coastal metropolises from New York to Mumbai, Hamburg and Shanghai”

“Coastal planning cannot merely rely on the best guess. It requires a risk analysis. Our study provides exactly that. The sea level contribution of Antarctica is very likely not going to be more than 58 centimetres.”

Thermal expansion of the oceans by global warming and the melting of glaciers, which so far have been the most important factors in sea level rise, will add to the contribution from Antarctic ice loss, making the overall sea level rise risk even bigger. But the ‘Antarctica Factor’ is about to become the most important element, according to the study, published in the journal Earth System Dynamics.

The range of sea-level rise estimates the scientists have come up with is fairly large. Assuming that humanity keeps on emitting greenhouse gases as before, they say, the range they call “very likely” to describe the future is between 6 and 58 cms for this century.

If greenhouse gas emissions were reduced rapidly, it would be between 4 and 37 cms. Importantly, the difference between a business-as-usual scenario and one of emissions reductions becomes substantially greater as time passes.

More robust insights

Sixteen ice sheet modelling groups consisting of 36 researchers from 27 institutes contributed to the new study. A similar study six years ago had to rely on the output of only five ice sheet models.

“The more computer simulation models we use, all of them with slightly different dynamic representations of the Antarctic ice sheet, the wider the range of results that we yield − but also the more robust the insights that we gain”, said co-author Sophie Nowicki of the NASA Goddard Space Flight Center.

“There are still large uncertainties, but we are constantly improving our understanding of the largest ice sheet on Earth. Comparing model outputs is a forceful tool to provide society with the necessary information for rational decisions.”

Over the long term, the Antarctic ice sheet has the potential ultimately to raise sea levels by many tens of metres. “What we know for certain”, said Professor Levermann, “is that not stopping the burning of coal, oil and gas will drive up the risks for coastal metropolises from New York to Mumbai, Hamburg and Shanghai.” − Climate News Network


Sea levels may threaten coastal cities sooner than expected, scientists say, as ice loss speeds up and Antarctic temperatures rise.

LONDON, 20 February, 2020 − Across the world, people now alive in coastal areas may face dangerously rising seas within their lifetimes, as record Antarctic temperatures and rapid melting of the continent’s ice drive global sea levels upwards.

Temperatures on the Antarctic Peninsula reached more than 20°C for the first time in history earlier this month, the Guardian reported: “The 20.75C logged by Brazilian scientists at Seymour Island on 9 February was almost a full degree higher than the previous record of 19.8C, taken on Signy Island in January 1982.”

The Antarctic Peninsula has warmed by almost 3°C since the start of the Industrial Revolution around 200 years ago − faster than almost anywhere else on Earth. But scientists are increasingly concerned not only about the Peninsula, but with the possibility that the entire southern continent may be heating up much faster than current estimates suggest.

Among evidence of increasing scientific effort to determine what is happening is a joint UK-US collaboration, due to report in 2023 on the chances of the collapse of the huge Thwaites glacier in West Antarctica, where from 1992 to 2017 the annual rate of ice loss rose threefold.

Big speed-up

Now a study by scientists co-ordinated by Germany’s Potsdam Institute for Climate Impact Research (PIK) says sea level rise caused by Antarctica’s ice loss could become a major risk for coastal protection in the near future.

After what they call “an exceptionally comprehensive comparison of state-of-the-art computer models from around the world”, they conclude that Antarctica alone could cause global sea level to rise by 2100 by up to three times more than it did in the last century.

“The ‘Antarctica Factor’ turns out to be the greatest risk, and also the greatest uncertainty, for sea levels around the globe,” says the lead author, Anders Levermann of PIK and Columbia University’s Lamont-Doherty Earth Observatory (LDEO) in New York.

“While we saw about 19 centimetres of sea level rise in the past 100 years, Antarctic ice loss could lead to up to 58 centimetres within this century”, he said.

“We know for certain that not stopping the burning of coal, oil and gas will drive up the risks for coastal metropolises from New York to Mumbai, Hamburg and Shanghai”

“Coastal planning cannot merely rely on the best guess. It requires a risk analysis. Our study provides exactly that. The sea level contribution of Antarctica is very likely not going to be more than 58 centimetres.”

Thermal expansion of the oceans by global warming and the melting of glaciers, which so far have been the most important factors in sea level rise, will add to the contribution from Antarctic ice loss, making the overall sea level rise risk even bigger. But the ‘Antarctica Factor’ is about to become the most important element, according to the study, published in the journal Earth System Dynamics.

The range of sea-level rise estimates the scientists have come up with is fairly large. Assuming that humanity keeps on emitting greenhouse gases as before, they say, the range they call “very likely” to describe the future is between 6 and 58 cms for this century.

If greenhouse gas emissions were reduced rapidly, it would be between 4 and 37 cms. Importantly, the difference between a business-as-usual scenario and one of emissions reductions becomes substantially greater as time passes.

More robust insights

Sixteen ice sheet modelling groups consisting of 36 researchers from 27 institutes contributed to the new study. A similar study six years ago had to rely on the output of only five ice sheet models.

“The more computer simulation models we use, all of them with slightly different dynamic representations of the Antarctic ice sheet, the wider the range of results that we yield − but also the more robust the insights that we gain”, said co-author Sophie Nowicki of the NASA Goddard Space Flight Center.

“There are still large uncertainties, but we are constantly improving our understanding of the largest ice sheet on Earth. Comparing model outputs is a forceful tool to provide society with the necessary information for rational decisions.”

Over the long term, the Antarctic ice sheet has the potential ultimately to raise sea levels by many tens of metres. “What we know for certain”, said Professor Levermann, “is that not stopping the burning of coal, oil and gas will drive up the risks for coastal metropolises from New York to Mumbai, Hamburg and Shanghai.” − Climate News Network

Can batteries help to limit bushfire horrors?

The Australian inferno has yet to reach its worst, but already minds are seeking ways to reduce the bushfire horrors. Could batteries help next time?

LONDON, 9 January, 2020 − With at least 27 human fatalities and a scarcely credible estimate by scientists that more than one billion animals have been killed nationwide by the unprecedented blazes  since September 2019, Australia’s bushfire horrors have stunned the world.

The climate crisis is contributing to the catastrophe, at least to its scale and intensity, whether or not it is its primary cause. And scientists revealed only this month that global heating is causing daily weather change.

But something else happened in Australia in 2019 which could point the way towards a fast route, not for Australia alone but globally, to renewable energy and a safer future.

In the state of South Australia the world’s biggest lithium-ion battery – 129MWh, able to power 30,000 homes for an hour during a blackout – was switched on just 60 days after the contract to build it was signed.

So ways of cutting the use of fossil fuels and reducing their contribution to climate heating, now clearly implicated in Australia’s catastrophe, are within reach.

The battery was commissioned in order to bring greater reliability and stability to the state’s electricity grid, preventing blackouts, improving reliability across the network and helping to even out price spikes.

The state’s efforts to increase its proportion of renewable energy had previously been hampered by freak weather which caused outages, which in turn sparked a political brawl over energy policy. The federal government blamed the supply failures on the use of renewable technologies.

40 days to spare

The state premier challenged the technology entrepreneur Elon Musk,  who replied by saying he would build a massive battery within 100 days of signing the deal. He managed it with 40 days to spare.

His approach − a familiar one in the renewable energy world − was to charge the battery packs when excess power was available and the cost of production very low, and then discharge them when the cost of power production rose.

The world is becoming increasingly reliant on battery power, largely because of the need to reduce carbon in the transport sector; almost 60% of new cars sold in Norway during March 2019 were entirely electric-powered. A recent World Economic Forum (WEF) report expects global battery demand to increase by more than 19 times its current levels in the next decade.

Batteries have historically been a dirty but convenient product, requiring the mining of metals such as nickel and zinc, yet considered disposable; landfills are strewn with these hazardous toxins, with more arriving every day. According to the US Environmental Protection Agency (EPA), each year Americans throw away more than three billion batteries – 180,000 tons of waste.

Yet the WEF report projects that new generation batteries could not only enable 30% of the required reductions in carbon emissions in the transport and power sectors, providing access to electricity to 600 million people who currently have no access; they will also create 10 million safe and sustainable jobs around the world.

Batteries will probably play a large part in future energy supply systems; in 2018, South Australia invested $100 million in a scheme to encourage householders to fit batteries to their solar systems, enabling them to use their own power on site rather than exporting it to the grid. This helps to reduce demand at peak times.

“The federal government blamed the supply failures on the use of renewable technologies”

Electric cars are not the only part of the transportation sector that will be in need of batteries. A number of companies are currently working on electric-powered commercial aircraft designs, and Norway is working on battery technology for shipping, with an all-electric passenger vessel already operating.

The Rapid Transition Alliance (RTA) is a UK-based organisation which argues that humankind must undertake “widespread behaviour change to sustainable lifestyles . . . to live within planetary ecological boundaries and to limit global warming to below 1.5°C”, with the slogan “Evidence-based hope for a warming world”.

It believes there is evidence that batteries can offer hope for Australia  and other countries facing similar lethal threats − provided they absorb several crucial lessons.

First, it says, technological leaps need both the flair of individual effort and the clout of institutional backing if they are to work at scale.

Then behavioural change must be practical and economically viable, because only a small minority of people will ever change for green reasons alone. Simply switching to electricity as a fuel source is not enough: to hit climate targets and maintain a habitable world, there needs to be an absolute reduction in energy consumption.

And finally, as batteries increasingly form part of the energy infrastructure, safeguards must be put in place around the mining involved in obtaining the minerals needed to make them, to ensure that poorer communities in the global South do not pay the price for cutting carbon emissions in richer countries. − Climate News Network

* * * * *

The Rapid Transition Alliance is coordinated by the New Weather Institute, the STEPS Centre at the Institute of  Development Studies, and the School of Global Studies at the University of Sussex, UK. The Climate News Network is partnering with and supported by the Rapid Transition Alliance, and will be reporting regularly on its work. If you would like to see more stories of evidence-based hope for rapid transition, please sign up here.

Do you know a story of rapid transition? If so, we’d like to hear from you. Please send us a brief outline on info@climatenewsnetwork.net. Thank you.

The Australian inferno has yet to reach its worst, but already minds are seeking ways to reduce the bushfire horrors. Could batteries help next time?

LONDON, 9 January, 2020 − With at least 27 human fatalities and a scarcely credible estimate by scientists that more than one billion animals have been killed nationwide by the unprecedented blazes  since September 2019, Australia’s bushfire horrors have stunned the world.

The climate crisis is contributing to the catastrophe, at least to its scale and intensity, whether or not it is its primary cause. And scientists revealed only this month that global heating is causing daily weather change.

But something else happened in Australia in 2019 which could point the way towards a fast route, not for Australia alone but globally, to renewable energy and a safer future.

In the state of South Australia the world’s biggest lithium-ion battery – 129MWh, able to power 30,000 homes for an hour during a blackout – was switched on just 60 days after the contract to build it was signed.

So ways of cutting the use of fossil fuels and reducing their contribution to climate heating, now clearly implicated in Australia’s catastrophe, are within reach.

The battery was commissioned in order to bring greater reliability and stability to the state’s electricity grid, preventing blackouts, improving reliability across the network and helping to even out price spikes.

The state’s efforts to increase its proportion of renewable energy had previously been hampered by freak weather which caused outages, which in turn sparked a political brawl over energy policy. The federal government blamed the supply failures on the use of renewable technologies.

40 days to spare

The state premier challenged the technology entrepreneur Elon Musk,  who replied by saying he would build a massive battery within 100 days of signing the deal. He managed it with 40 days to spare.

His approach − a familiar one in the renewable energy world − was to charge the battery packs when excess power was available and the cost of production very low, and then discharge them when the cost of power production rose.

The world is becoming increasingly reliant on battery power, largely because of the need to reduce carbon in the transport sector; almost 60% of new cars sold in Norway during March 2019 were entirely electric-powered. A recent World Economic Forum (WEF) report expects global battery demand to increase by more than 19 times its current levels in the next decade.

Batteries have historically been a dirty but convenient product, requiring the mining of metals such as nickel and zinc, yet considered disposable; landfills are strewn with these hazardous toxins, with more arriving every day. According to the US Environmental Protection Agency (EPA), each year Americans throw away more than three billion batteries – 180,000 tons of waste.

Yet the WEF report projects that new generation batteries could not only enable 30% of the required reductions in carbon emissions in the transport and power sectors, providing access to electricity to 600 million people who currently have no access; they will also create 10 million safe and sustainable jobs around the world.

Batteries will probably play a large part in future energy supply systems; in 2018, South Australia invested $100 million in a scheme to encourage householders to fit batteries to their solar systems, enabling them to use their own power on site rather than exporting it to the grid. This helps to reduce demand at peak times.

“The federal government blamed the supply failures on the use of renewable technologies”

Electric cars are not the only part of the transportation sector that will be in need of batteries. A number of companies are currently working on electric-powered commercial aircraft designs, and Norway is working on battery technology for shipping, with an all-electric passenger vessel already operating.

The Rapid Transition Alliance (RTA) is a UK-based organisation which argues that humankind must undertake “widespread behaviour change to sustainable lifestyles . . . to live within planetary ecological boundaries and to limit global warming to below 1.5°C”, with the slogan “Evidence-based hope for a warming world”.

It believes there is evidence that batteries can offer hope for Australia  and other countries facing similar lethal threats − provided they absorb several crucial lessons.

First, it says, technological leaps need both the flair of individual effort and the clout of institutional backing if they are to work at scale.

Then behavioural change must be practical and economically viable, because only a small minority of people will ever change for green reasons alone. Simply switching to electricity as a fuel source is not enough: to hit climate targets and maintain a habitable world, there needs to be an absolute reduction in energy consumption.

And finally, as batteries increasingly form part of the energy infrastructure, safeguards must be put in place around the mining involved in obtaining the minerals needed to make them, to ensure that poorer communities in the global South do not pay the price for cutting carbon emissions in richer countries. − Climate News Network

* * * * *

The Rapid Transition Alliance is coordinated by the New Weather Institute, the STEPS Centre at the Institute of  Development Studies, and the School of Global Studies at the University of Sussex, UK. The Climate News Network is partnering with and supported by the Rapid Transition Alliance, and will be reporting regularly on its work. If you would like to see more stories of evidence-based hope for rapid transition, please sign up here.

Do you know a story of rapid transition? If so, we’d like to hear from you. Please send us a brief outline on info@climatenewsnetwork.net. Thank you.

Little time left to arrest Greenland’s melting

Humans may still have time to stop Greenland’s melting, preventing Arctic ice sheet collapse and devastating sea level rise. But the time left may be short.

LONDON, 30 December, 2019 – It’s still possible, but it’s far from certain: stopping Greenland’s melting can be done, but it must be done soon.

Norwegian and US scientists have taken a close look at the ice age history of Greenland and come to a grim conclusion. All it takes to set the island’s ice cap melting away is a mean sea surface temperature higher than seven degrees Celsius. And the present mean sea surface temperature is already 7.7°C.

Greenland is the northern hemisphere’s single richest store of frozen water: the island’s bedrock holds enough to raise global sea levels by seven metres and drown or wash away the world’s coastal communities, including the great cities of New York and Miami, Shanghai and Kolkata, Amsterdam and London.

And the pattern of geological evidence – outlined in the Proceedings of the National Academy of Sciences – combined with climate models suggests that any sustained temperature rise could trigger an irreversible melt of the entire southern Greenland ice sheet.

The scientists suggest that the threshold for this calamity could be between 0.8°C above the post-Ice Age norm, and 3.2°C.

“The critical temperature threshold for past Greenland ice sheet decay will likely be surpassed this century”

In fact, because of profligate use of fossil fuels and the release of greenhouse gases into the atmosphere, the planet has already warmed by around 1°C above the level for most of human history, and warming of at least 3.2°C by the end of this century now seems almost certain.

Researchers publish their conclusions with the intention that they should be examined, tested, challenged and perhaps overturned. But widespread alarm at the rate of melt and mass loss in Greenland has been consistent and increasing with the years.

Researchers have repeatedly established that melting each summer is increasing the rate at which glaciers flow and deliver ice to increasingly warmer northern seas, and that this rate of melting has itself begun to accelerate.

So Nil Irvali of the University of Bergen and colleagues took a closer look at the story told by microfossils within cores from the ice and the ocean floor during four interglacial periods over the last 450,000 years.

During those warm spells ocean levels rose dramatically, and in two episodes Greenland’s vanishing ice could have contributed more than five metres in one case, and up to seven metres of sea level rise in the other.

Triggers identified

And in all four of those interglacials, conditions reached temperatures higher than they are right now.

Concern about the stability of the Greenland icecap is no surprise: the Arctic is already warming faster than anywhere else on the planet, thanks to profligate use of fossil fuels and the destruction of the rainforests, and researchers worldwide have begun to identify triggers that feed back into further warming: rain, for instance, in winter; the loss of cloud cover in summer; and the deposits of soot from polar wildfires that darken the snows and enhance the absorption of the sun’s rays.

Years ago, the phrase “at a glacial pace” ceased to be a valid cliché: US scientists clocked one river of ice moving at a rate of 46 metres a day.

So the new study simply confirms fears that already are widespread. What remains to be settled is the point at which the decline of the ice sheet becomes irreversible, the Bergen scientists say. As the ocean warms, this feeds back into the process of melting and triggers longer-term feedbacks.

“The exact point at which these feedbacks are triggered remains equivocal,” say Dr Irvali and her co-authors. “Notably, the critical temperature threshold for past Greenland ice sheet decay will likely be surpassed this century. The duration for which this threshold is exceeded will determine Greenland’s fate.” – Climate News Network

Humans may still have time to stop Greenland’s melting, preventing Arctic ice sheet collapse and devastating sea level rise. But the time left may be short.

LONDON, 30 December, 2019 – It’s still possible, but it’s far from certain: stopping Greenland’s melting can be done, but it must be done soon.

Norwegian and US scientists have taken a close look at the ice age history of Greenland and come to a grim conclusion. All it takes to set the island’s ice cap melting away is a mean sea surface temperature higher than seven degrees Celsius. And the present mean sea surface temperature is already 7.7°C.

Greenland is the northern hemisphere’s single richest store of frozen water: the island’s bedrock holds enough to raise global sea levels by seven metres and drown or wash away the world’s coastal communities, including the great cities of New York and Miami, Shanghai and Kolkata, Amsterdam and London.

And the pattern of geological evidence – outlined in the Proceedings of the National Academy of Sciences – combined with climate models suggests that any sustained temperature rise could trigger an irreversible melt of the entire southern Greenland ice sheet.

The scientists suggest that the threshold for this calamity could be between 0.8°C above the post-Ice Age norm, and 3.2°C.

“The critical temperature threshold for past Greenland ice sheet decay will likely be surpassed this century”

In fact, because of profligate use of fossil fuels and the release of greenhouse gases into the atmosphere, the planet has already warmed by around 1°C above the level for most of human history, and warming of at least 3.2°C by the end of this century now seems almost certain.

Researchers publish their conclusions with the intention that they should be examined, tested, challenged and perhaps overturned. But widespread alarm at the rate of melt and mass loss in Greenland has been consistent and increasing with the years.

Researchers have repeatedly established that melting each summer is increasing the rate at which glaciers flow and deliver ice to increasingly warmer northern seas, and that this rate of melting has itself begun to accelerate.

So Nil Irvali of the University of Bergen and colleagues took a closer look at the story told by microfossils within cores from the ice and the ocean floor during four interglacial periods over the last 450,000 years.

During those warm spells ocean levels rose dramatically, and in two episodes Greenland’s vanishing ice could have contributed more than five metres in one case, and up to seven metres of sea level rise in the other.

Triggers identified

And in all four of those interglacials, conditions reached temperatures higher than they are right now.

Concern about the stability of the Greenland icecap is no surprise: the Arctic is already warming faster than anywhere else on the planet, thanks to profligate use of fossil fuels and the destruction of the rainforests, and researchers worldwide have begun to identify triggers that feed back into further warming: rain, for instance, in winter; the loss of cloud cover in summer; and the deposits of soot from polar wildfires that darken the snows and enhance the absorption of the sun’s rays.

Years ago, the phrase “at a glacial pace” ceased to be a valid cliché: US scientists clocked one river of ice moving at a rate of 46 metres a day.

So the new study simply confirms fears that already are widespread. What remains to be settled is the point at which the decline of the ice sheet becomes irreversible, the Bergen scientists say. As the ocean warms, this feeds back into the process of melting and triggers longer-term feedbacks.

“The exact point at which these feedbacks are triggered remains equivocal,” say Dr Irvali and her co-authors. “Notably, the critical temperature threshold for past Greenland ice sheet decay will likely be surpassed this century. The duration for which this threshold is exceeded will determine Greenland’s fate.” – Climate News Network

Marine climate impacts are intensifying

Fish catches are falling in the Gulf of Maine, Baltic cod are getting smaller. Sharks suffer acid waters’ effects as marine climate impacts grow.

LONDON, 20 December, 2019 – Marine climate impacts are starting to make their mark on marine life at almost every level, according to a range of entirely unrelated scientific studies published in the last month.

Baltic codfish – a valuable commercial catch – have steadily become smaller, scrawnier and less valuable because of the loss of oxygen in ocean waters as a consequence of an increasingly warmer world.

Changes in climate over the last two decades have cost the fishermen of New England their jobs: their numbers have fallen by 16% since 1996 as the total catch has fallen, along with fishermen’s incomes.

The change may be linked to a natural ocean climate cycle, but nobody can be sure the decline will not continue as waters warm in response to ever higher atmospheric levels of carbon dioxide, driven by ever greater use of fossil fuels to power modern economic growth.

That steady rise in carbon dioxide means that marine waters are also becoming steadily more acidic, and this could be bad news for the sharks. Laboratory experiments suggest they can respond to short-term changes in water chemistry, but in the long term increasingly acidic waters can begin to dissolve not just the characteristic skin scales of the shark family, but the teeth as well.

And if environmental change goes on hitting tropical corals and the anemones that co-exist with them, then one of the world’s most iconic and culturally popular species could also disappear: the clownfish sub-family Amphiprioninae may not survive the continued bleaching of the coral reefs. Amphiprion ocellaris swam into the world’s hearts as the much sought-after cartoon character in the 2003 film Finding Nemo.

“We find that Nemo is at the mercy of a habitat that is degrading more and more every year”

Scientists based in the US and Sweden report in the journal Biology Letters that the average weight of specimens of Gadus morhua or the cod fish 40 cms long had dropped from 900 to 600 grams in the last 30 years.

They examined the otoliths or ear stones of 134 individuals trawled in the last months of the Baltic winter to read the evidence from trace elements such as magnesium and manganese and identify the cause: the continued fall in sea water oxygen levels as a consequence of global warming and pollution.

“The cod themselves are telling us through their internal logbooks that they’re affected by hypoxia [reduced oxygen availability], which we know is driven by climate change and nutrient loading,” said Karin Limburg, an ecologist at the State University of New York, who led the study. “Our findings suggest fish are in a worse condition because of hypoxia.”

In the Gulf of Maine, off the US Atlantic coast, catches of fish and shellfish have been falling, and with them the number of people employed in the fishery. Kimberly Oremus of the University of Delaware reports in the Proceedings of the National Academy of Sciences that successive warm winters have hit the catch, and incomes.

Pattern found

She matched decades of climate data, landing figures and sales data to identify a pattern of decline linked principally to a hot-and-cold pattern of change known as the North Atlantic Oscillation.

“New England waters are among the fastest-warming in the world,” she said. “Warmer than average sea surface temperatures have been shown to impact the productivity of lobsters, sea scallops, groundfish and other fisheries important to the region, especially when they are most vulnerable, from spawning through their first year of life.”

The region has 34,000 commercial fishermen, a significant proportion of the 166,000 or so throughout the whole of the US. The oscillation is a shift in ocean temperatures over decades, and catches could improve in decades to come – but marine waters worldwide are warming.

“This is an important signal to incorporate into the fisheries management process,” she said. “We need to figure out what climate is doing to fisheries in order to cope with it.”

Acid hazard

One important part of the marine ecosystem might not in the long run be able to cope: short episodes of hypercapnia, or a dramatic rise in dissolved carbon dioxide, are a feature linked to seasonal oceanic upwellings, and can last for days in some waters before normal ocean chemistry is restored.

In the journal Scientific Reports, European and South Africa researchers offer evidence that though cartilaginous fishes – the huge and varied family to which sharks belong – have evolved to cope with such spells, ever more acidic oceans offer a new hazard.

They caught a number of puffadder shysharks, known to scientists as Haploblepharus edwardsii and a species small enough for laboratory tanks, from shallow waters off South Africa and exposed them to acidic conditions predicted by the year 2300.

The increasingly acid environment was, literally, corrosive. Their specimens lost a quarter of their skin denticles – the shark equivalent of scales. Sharks’ teeth are made of the same biological fabric as the skin, and the implication is that such losses could, in their words “compromise hydrodynamics and skin protection.” In other words, some of the ocean’s most feared predators might have trouble both swimming and feeding.

Poor adapters

Australian and US scientists have more bad news for Nemo, the film star from the clownfish family. Rather than experiment in a laboratory tank, they monitored the numbers and the DNA of real life specimens for decades in Kimbe Bay off Papua-New Guinea. As waters warmed and began to bleach the coral reefs, the anemones that live in the reefs were put at risk.

They report in Ecology Letters that the tiny clownfish that live in the anemone tentacles proved bad at adapting to environmental change. The implication is that, as the coral reefs are lost, many species could be homeless and helpless.

“We find that Nemo is at the mercy of a habitat that is degrading more and more every year,” said Serge Planes of the French National Centre of Scientific Research, and one of the authors.

“To expect a clownfish to genetically adapt at a pace that would allow it to persist is unreasonable.” And Simon Thorrold of the Woods Hole Oceanographic Institution in the US added: “It seems Nemo won’t be able to save himself.” – Climate News Network

Fish catches are falling in the Gulf of Maine, Baltic cod are getting smaller. Sharks suffer acid waters’ effects as marine climate impacts grow.

LONDON, 20 December, 2019 – Marine climate impacts are starting to make their mark on marine life at almost every level, according to a range of entirely unrelated scientific studies published in the last month.

Baltic codfish – a valuable commercial catch – have steadily become smaller, scrawnier and less valuable because of the loss of oxygen in ocean waters as a consequence of an increasingly warmer world.

Changes in climate over the last two decades have cost the fishermen of New England their jobs: their numbers have fallen by 16% since 1996 as the total catch has fallen, along with fishermen’s incomes.

The change may be linked to a natural ocean climate cycle, but nobody can be sure the decline will not continue as waters warm in response to ever higher atmospheric levels of carbon dioxide, driven by ever greater use of fossil fuels to power modern economic growth.

That steady rise in carbon dioxide means that marine waters are also becoming steadily more acidic, and this could be bad news for the sharks. Laboratory experiments suggest they can respond to short-term changes in water chemistry, but in the long term increasingly acidic waters can begin to dissolve not just the characteristic skin scales of the shark family, but the teeth as well.

And if environmental change goes on hitting tropical corals and the anemones that co-exist with them, then one of the world’s most iconic and culturally popular species could also disappear: the clownfish sub-family Amphiprioninae may not survive the continued bleaching of the coral reefs. Amphiprion ocellaris swam into the world’s hearts as the much sought-after cartoon character in the 2003 film Finding Nemo.

“We find that Nemo is at the mercy of a habitat that is degrading more and more every year”

Scientists based in the US and Sweden report in the journal Biology Letters that the average weight of specimens of Gadus morhua or the cod fish 40 cms long had dropped from 900 to 600 grams in the last 30 years.

They examined the otoliths or ear stones of 134 individuals trawled in the last months of the Baltic winter to read the evidence from trace elements such as magnesium and manganese and identify the cause: the continued fall in sea water oxygen levels as a consequence of global warming and pollution.

“The cod themselves are telling us through their internal logbooks that they’re affected by hypoxia [reduced oxygen availability], which we know is driven by climate change and nutrient loading,” said Karin Limburg, an ecologist at the State University of New York, who led the study. “Our findings suggest fish are in a worse condition because of hypoxia.”

In the Gulf of Maine, off the US Atlantic coast, catches of fish and shellfish have been falling, and with them the number of people employed in the fishery. Kimberly Oremus of the University of Delaware reports in the Proceedings of the National Academy of Sciences that successive warm winters have hit the catch, and incomes.

Pattern found

She matched decades of climate data, landing figures and sales data to identify a pattern of decline linked principally to a hot-and-cold pattern of change known as the North Atlantic Oscillation.

“New England waters are among the fastest-warming in the world,” she said. “Warmer than average sea surface temperatures have been shown to impact the productivity of lobsters, sea scallops, groundfish and other fisheries important to the region, especially when they are most vulnerable, from spawning through their first year of life.”

The region has 34,000 commercial fishermen, a significant proportion of the 166,000 or so throughout the whole of the US. The oscillation is a shift in ocean temperatures over decades, and catches could improve in decades to come – but marine waters worldwide are warming.

“This is an important signal to incorporate into the fisheries management process,” she said. “We need to figure out what climate is doing to fisheries in order to cope with it.”

Acid hazard

One important part of the marine ecosystem might not in the long run be able to cope: short episodes of hypercapnia, or a dramatic rise in dissolved carbon dioxide, are a feature linked to seasonal oceanic upwellings, and can last for days in some waters before normal ocean chemistry is restored.

In the journal Scientific Reports, European and South Africa researchers offer evidence that though cartilaginous fishes – the huge and varied family to which sharks belong – have evolved to cope with such spells, ever more acidic oceans offer a new hazard.

They caught a number of puffadder shysharks, known to scientists as Haploblepharus edwardsii and a species small enough for laboratory tanks, from shallow waters off South Africa and exposed them to acidic conditions predicted by the year 2300.

The increasingly acid environment was, literally, corrosive. Their specimens lost a quarter of their skin denticles – the shark equivalent of scales. Sharks’ teeth are made of the same biological fabric as the skin, and the implication is that such losses could, in their words “compromise hydrodynamics and skin protection.” In other words, some of the ocean’s most feared predators might have trouble both swimming and feeding.

Poor adapters

Australian and US scientists have more bad news for Nemo, the film star from the clownfish family. Rather than experiment in a laboratory tank, they monitored the numbers and the DNA of real life specimens for decades in Kimbe Bay off Papua-New Guinea. As waters warmed and began to bleach the coral reefs, the anemones that live in the reefs were put at risk.

They report in Ecology Letters that the tiny clownfish that live in the anemone tentacles proved bad at adapting to environmental change. The implication is that, as the coral reefs are lost, many species could be homeless and helpless.

“We find that Nemo is at the mercy of a habitat that is degrading more and more every year,” said Serge Planes of the French National Centre of Scientific Research, and one of the authors.

“To expect a clownfish to genetically adapt at a pace that would allow it to persist is unreasonable.” And Simon Thorrold of the Woods Hole Oceanographic Institution in the US added: “It seems Nemo won’t be able to save himself.” – Climate News Network

Glacial melt creates Andes time bomb

The speed of glacial melt in parts of Latin America is threatening water supplies – and life and limb in cities downstream.

LONDON, 16 December, 2019 – Rising regional temperatures in the Andes and the warming of waters in the Pacific Ocean, off Latin America’s west coast, are driving the mountains’ glacial melt to alarming new speeds.

Long-term water supplies to many millions of people are under threat. Capital cities like Lima in Peru and La Paz in Bolivia, largely dependent on water from glacier melt flows, face an uncertain future.

The prospects for agriculture – a mainstay of the economies of countries in the region – will be imperilled as land dries up.

There is another, potentially lethal consequence of the melting of the Andes’ glaciers. In 1941, large chunks of ice breaking off a glacier and falling into Lake Palcacocha, more than 4,500 metres up in the Cordillera Blanca mountain range in the Peruvian Andes, are said to have triggered what’s known as a glacial lake outburst flood (GLOF).

“As temperatures in the region continue to rise, the danger level increases”

The sudden influx of ice caused the lake to burst, its waters racing down a canyon to burst another glacial lake below and then on to flood the city of Huarez, more than 20 kilometres away. It’s estimated that more than 4,000 people – about a third of the city’s population at the time – were killed.

Rising temperatures caused by climate change in mountain ranges around the world are leading to an ever-increasing number of GLOF incidents. Mountainous countries like Peru and Nepal, in the Himalayas, are particularly vulnerable to the sudden flooding caused when glacial lakes burst.

In the aftermath of the 1941 flood, a dam was built on Lake Palcacocha: at first the lake slowly refilled, but in recent years the process accelerated due to increased temperatures and more glacial melt.

Flexible pipes have been used to siphon waters off from the lake but experts say it’s only a matter of time before Lake Palcacocha again bursts its banks. The dam, they say, will be swept away. The consequences would be devastating as a wave up to 30 metres tall is unleashed.

Increased population

The city of Huarez has become a big tourist destination and its population has grown to more than 120,000. Large numbers of farmers have moved onto lands below Lake Palcacocha. Mine workers are also active in the area, searching for valuable minerals in ground uncovered by the melting of the glaciers.

Various safety measures are being installed. After years of wrangling and bureaucratic delays, a flood early warning system is about to be activated in the area.

Installation of the system has also been subject to sabotage by local farmers who say that the introduction of the technology has somehow interfered with natural weather patterns.

Monitoring systems have improved – with often daily glacial avalanches being recorded. Inaigem, the national research institute on glaciers and mountain ecosystems, provides a live video of Lake Palcacocha water flows. But as temperatures in the region continue to rise, the danger level increases. – Climate News Network

The speed of glacial melt in parts of Latin America is threatening water supplies – and life and limb in cities downstream.

LONDON, 16 December, 2019 – Rising regional temperatures in the Andes and the warming of waters in the Pacific Ocean, off Latin America’s west coast, are driving the mountains’ glacial melt to alarming new speeds.

Long-term water supplies to many millions of people are under threat. Capital cities like Lima in Peru and La Paz in Bolivia, largely dependent on water from glacier melt flows, face an uncertain future.

The prospects for agriculture – a mainstay of the economies of countries in the region – will be imperilled as land dries up.

There is another, potentially lethal consequence of the melting of the Andes’ glaciers. In 1941, large chunks of ice breaking off a glacier and falling into Lake Palcacocha, more than 4,500 metres up in the Cordillera Blanca mountain range in the Peruvian Andes, are said to have triggered what’s known as a glacial lake outburst flood (GLOF).

“As temperatures in the region continue to rise, the danger level increases”

The sudden influx of ice caused the lake to burst, its waters racing down a canyon to burst another glacial lake below and then on to flood the city of Huarez, more than 20 kilometres away. It’s estimated that more than 4,000 people – about a third of the city’s population at the time – were killed.

Rising temperatures caused by climate change in mountain ranges around the world are leading to an ever-increasing number of GLOF incidents. Mountainous countries like Peru and Nepal, in the Himalayas, are particularly vulnerable to the sudden flooding caused when glacial lakes burst.

In the aftermath of the 1941 flood, a dam was built on Lake Palcacocha: at first the lake slowly refilled, but in recent years the process accelerated due to increased temperatures and more glacial melt.

Flexible pipes have been used to siphon waters off from the lake but experts say it’s only a matter of time before Lake Palcacocha again bursts its banks. The dam, they say, will be swept away. The consequences would be devastating as a wave up to 30 metres tall is unleashed.

Increased population

The city of Huarez has become a big tourist destination and its population has grown to more than 120,000. Large numbers of farmers have moved onto lands below Lake Palcacocha. Mine workers are also active in the area, searching for valuable minerals in ground uncovered by the melting of the glaciers.

Various safety measures are being installed. After years of wrangling and bureaucratic delays, a flood early warning system is about to be activated in the area.

Installation of the system has also been subject to sabotage by local farmers who say that the introduction of the technology has somehow interfered with natural weather patterns.

Monitoring systems have improved – with often daily glacial avalanches being recorded. Inaigem, the national research institute on glaciers and mountain ecosystems, provides a live video of Lake Palcacocha water flows. But as temperatures in the region continue to rise, the danger level increases. – Climate News Network

Worst hurricanes both more frequent and harmful

The worst hurricanes are increasing. It’s not just that there are more potential victims than before. There are also more disastrous storms.

LONDON, 3 December, 2019 – Danish researchers have settled a problem of US disaster accounting, confirming that in the last century North America’s worst hurricanes have become three times more frequent – and significantly more destructive.

Such calculations sound as though they ought to be simple. They are not. In 1900, the entire population of the planet was about 1.6 billion people, most of whom lived in rural areas. By 2018, global population had reached 7.5 billion, and more than half of the world was concentrated in cities. In effect, any hurricane would threaten more victims, and there would be more, and more expensive, property to be destroyed.

So the damage from hurricanes would tend always to rise, and the count of destructive hurricanes would grow, because any violent windstorm would be more likely to slam into an urban area rather than sweep over a few farms.

Tropical cyclones, typhoons and hurricanes start at sea, as sea surface temperatures rise. With ever-increasing global temperatures, driven by profligate combustion of fossil fuels, more hurricanes would be expected, with higher windspeeds and ever-greater burdens of rain to bring disastrous floods as well as severe damage.

“The frequency of the most damaging hurricanes has increased at the rate of 350% per century”

But it is harder to show that the climate crisis is intrinsically more dangerous, even though windstorm damage is on the rise. Researchers tend to use economic accounting to try to work out what a hurricane in, for example 1950, would cost if it swept in from the ocean today.

Hurricanes are the costliest natural disasters in the US. Scientists at the Niels Bohr Institute in Copenhagen set about making their comparisons in a new way. Rather than match financial losses on a case by case basis, they tried to calculate how large an area would have to be completely destroyed to account for a particular financial loss.

They extended this “area of total destruction” accounting back to 1900, to see what the new comparison approach would reveal.

And, they report in the Proceedings of the National Academy of Sciences, they found what they call “an emergent positive trend in damage, which we attribute to a detectable change in extreme storms due to global warming.” And they add: “The frequency of the most damaging hurricanes has increased at the rate of 350% per century.” – Climate News Network.

The worst hurricanes are increasing. It’s not just that there are more potential victims than before. There are also more disastrous storms.

LONDON, 3 December, 2019 – Danish researchers have settled a problem of US disaster accounting, confirming that in the last century North America’s worst hurricanes have become three times more frequent – and significantly more destructive.

Such calculations sound as though they ought to be simple. They are not. In 1900, the entire population of the planet was about 1.6 billion people, most of whom lived in rural areas. By 2018, global population had reached 7.5 billion, and more than half of the world was concentrated in cities. In effect, any hurricane would threaten more victims, and there would be more, and more expensive, property to be destroyed.

So the damage from hurricanes would tend always to rise, and the count of destructive hurricanes would grow, because any violent windstorm would be more likely to slam into an urban area rather than sweep over a few farms.

Tropical cyclones, typhoons and hurricanes start at sea, as sea surface temperatures rise. With ever-increasing global temperatures, driven by profligate combustion of fossil fuels, more hurricanes would be expected, with higher windspeeds and ever-greater burdens of rain to bring disastrous floods as well as severe damage.

“The frequency of the most damaging hurricanes has increased at the rate of 350% per century”

But it is harder to show that the climate crisis is intrinsically more dangerous, even though windstorm damage is on the rise. Researchers tend to use economic accounting to try to work out what a hurricane in, for example 1950, would cost if it swept in from the ocean today.

Hurricanes are the costliest natural disasters in the US. Scientists at the Niels Bohr Institute in Copenhagen set about making their comparisons in a new way. Rather than match financial losses on a case by case basis, they tried to calculate how large an area would have to be completely destroyed to account for a particular financial loss.

They extended this “area of total destruction” accounting back to 1900, to see what the new comparison approach would reveal.

And, they report in the Proceedings of the National Academy of Sciences, they found what they call “an emergent positive trend in damage, which we attribute to a detectable change in extreme storms due to global warming.” And they add: “The frequency of the most damaging hurricanes has increased at the rate of 350% per century.” – Climate News Network.

Earth nears irreversible tipping points

Changes afoot now in at least nine areas could drastically alter the Earth’s climate. There’s no time left to act on these tipping points.

LONDON, 28 November, 2019 – On the eve of a global climate summit in Madrid, seven distinguished climate scientists have issued an urgent warning of approaching planetary tipping points: within a few years, they say, humankind could enter a state of potentially catastrophic climate change on a new “hothouse” Earth.

They warn that dramatic changes to planetary stability may already be happening in nine vulnerable ecosystems. As these changes happen, they could reinforce each other and at the same time amplify planetary temperature rise, commit the oceans to inexorable sea level rise of around 10 metres, and threaten the existence of human civilisations.

Their warning is issued in a commentary in the journal Nature. Their conclusions are not – and perhaps cannot be – confirmed by direct evidence or the consensus of other scientists. They present an opinion, not a set of facts that can be scrutinised and challenged or endorsed by their peers.

And the seven researchers recognise that although such changes are happening at speed, some of the consequences of those changes will follow more slowly. Their point is that the risks of irreversible change are too great not to act – and to act now.

Happening now

But the fact that they have chosen to issue such an alarm at all is a measure of the concern raised by the rapid retreat of the Arctic ice, the steady loss of the Greenland ice cap, the damage to the boreal forests, the thaw of the polar permafrost, the slowing of a great ocean current, the loss of tropical corals and the collapse of ice sheets in East and West Antarctica.

Each of these happenings – and many more – was identified more than a decade ago as a potential “tipping point”: an irreversible change that would amplify global heating and trigger a cascade of other climate changes.

“Now we see evidence that over half of them have been activated,” said Tim Lenton of the University of Exeter, UK. “The growing threat of rapid, irreversible changes means it is no longer responsible to wait and see.”

“The stability and resilience of our planet is in peril. International action – not just words – must reflect this”

The idea of a climate tipping point – a threshold beyond which dramatic climate change would be irreversible – is an old one. Two decades ago the Intergovernmental Panel on Climate Change examined the idea and proposed that, were the planet to warm by 5°C above the long-term average for most of human history, then it could tip into a new climate regime.

But in the last few decades, carbon dioxide concentrations in the atmosphere have gone from around 280 parts per million to more than 400 ppm, and global average temperatures have risen by more than 1°C. And the rate of change, driven by profligate use of fossil fuels that deposit greenhouse gases into the atmosphere, has been alarming.

“It is not only human pressures on Earth that continue rising to unprecedented levels. It is also that, as science advances, we must admit that we have underestimated the risks of unleashing irreversible changes, where the planet self-amplifies global warming. This is what we are seeing already at 1°C global warming,” said Johan Rockström, who directs the Potsdam Institute for Climate Impact Research in Germany, and who is another signatory.

“Scientifically, this provides strong evidence for declaring a state of planetary emergency, to unleash world action that accelerates the path towards a world that can continue evolving on a stable planet.”

Inadequate pledges

In 2015, at a climate summit in Paris, 195 nations promised to contain planetary heating to “well below” 2°C, and ideally to 1.5°C, by 2100. But the Nature signatories point at that even if the pledges those nations made are implemented – a “big if”, they warn – then they will ensure only that the world is committed to at least 3°C warming.

The scientists believe there is still time to act – but their dangerous tipping points are now dangerously close.

The arguments go like this. In West Antarctica, ice may already be retreating beyond the “grounding line” where ice, ocean and bedrock meet. If so, then the rest of the West Antarctic ice sheet could collapse, and sea levels could rise by three metres.

New evidence suggests the East Antarctic ice sheet could be similarly unstable, and precipitate further sea level rise of up to four metres. Hundreds of millions are already at risk from coastal flooding.

Timescale controlled

The Greenland ice sheet is melting at an accelerating rate, and once past a critical threshold could lose enough water to raise sea levels by seven metres. Even a 1.5°C warming might condemn Greenland to irreversible melting – and on present form the world could warm by 1.5°C by 2030.

“Thus we might have already committed future generations to living with sea level rises of around 10m over thousands of years. But the timescale is still under our control,” the authors warn.

They also warn that a “staggering 99% of tropical corals” could be lost if the planet heats by even 2°C – at a profound cost to both marine sea life and human economies.

They say 17% of the Amazon rainforest has been lost since 1970: a loss of somewhere between 20% and 40% could tip the entire rainforest into a destabilised state, increasingly at risk from drought and fire.

Risks multiply

In the boreal forests of northern Asia, Europe and Canada, insect outbreaks, fire and dieback could turn some regions into sources of more carbon, rather than sinks that soak up the extra carbon dioxide.

Permafrost thaw could release ever-greater volumes of stored methane, a greenhouse gas 30 times more potent, over a century, than carbon dioxide, and so on. The dangers multiply, and each one amplifies planetary heating.

“If damaging tipping cascades can occur and a global tipping point cannot be ruled out, then this is an existential threat to civilisation,” the authors warn.

“The stability and resilience of our planet is in peril. International action – not just words – must reflect this.” – Climate News Network

Changes afoot now in at least nine areas could drastically alter the Earth’s climate. There’s no time left to act on these tipping points.

LONDON, 28 November, 2019 – On the eve of a global climate summit in Madrid, seven distinguished climate scientists have issued an urgent warning of approaching planetary tipping points: within a few years, they say, humankind could enter a state of potentially catastrophic climate change on a new “hothouse” Earth.

They warn that dramatic changes to planetary stability may already be happening in nine vulnerable ecosystems. As these changes happen, they could reinforce each other and at the same time amplify planetary temperature rise, commit the oceans to inexorable sea level rise of around 10 metres, and threaten the existence of human civilisations.

Their warning is issued in a commentary in the journal Nature. Their conclusions are not – and perhaps cannot be – confirmed by direct evidence or the consensus of other scientists. They present an opinion, not a set of facts that can be scrutinised and challenged or endorsed by their peers.

And the seven researchers recognise that although such changes are happening at speed, some of the consequences of those changes will follow more slowly. Their point is that the risks of irreversible change are too great not to act – and to act now.

Happening now

But the fact that they have chosen to issue such an alarm at all is a measure of the concern raised by the rapid retreat of the Arctic ice, the steady loss of the Greenland ice cap, the damage to the boreal forests, the thaw of the polar permafrost, the slowing of a great ocean current, the loss of tropical corals and the collapse of ice sheets in East and West Antarctica.

Each of these happenings – and many more – was identified more than a decade ago as a potential “tipping point”: an irreversible change that would amplify global heating and trigger a cascade of other climate changes.

“Now we see evidence that over half of them have been activated,” said Tim Lenton of the University of Exeter, UK. “The growing threat of rapid, irreversible changes means it is no longer responsible to wait and see.”

“The stability and resilience of our planet is in peril. International action – not just words – must reflect this”

The idea of a climate tipping point – a threshold beyond which dramatic climate change would be irreversible – is an old one. Two decades ago the Intergovernmental Panel on Climate Change examined the idea and proposed that, were the planet to warm by 5°C above the long-term average for most of human history, then it could tip into a new climate regime.

But in the last few decades, carbon dioxide concentrations in the atmosphere have gone from around 280 parts per million to more than 400 ppm, and global average temperatures have risen by more than 1°C. And the rate of change, driven by profligate use of fossil fuels that deposit greenhouse gases into the atmosphere, has been alarming.

“It is not only human pressures on Earth that continue rising to unprecedented levels. It is also that, as science advances, we must admit that we have underestimated the risks of unleashing irreversible changes, where the planet self-amplifies global warming. This is what we are seeing already at 1°C global warming,” said Johan Rockström, who directs the Potsdam Institute for Climate Impact Research in Germany, and who is another signatory.

“Scientifically, this provides strong evidence for declaring a state of planetary emergency, to unleash world action that accelerates the path towards a world that can continue evolving on a stable planet.”

Inadequate pledges

In 2015, at a climate summit in Paris, 195 nations promised to contain planetary heating to “well below” 2°C, and ideally to 1.5°C, by 2100. But the Nature signatories point at that even if the pledges those nations made are implemented – a “big if”, they warn – then they will ensure only that the world is committed to at least 3°C warming.

The scientists believe there is still time to act – but their dangerous tipping points are now dangerously close.

The arguments go like this. In West Antarctica, ice may already be retreating beyond the “grounding line” where ice, ocean and bedrock meet. If so, then the rest of the West Antarctic ice sheet could collapse, and sea levels could rise by three metres.

New evidence suggests the East Antarctic ice sheet could be similarly unstable, and precipitate further sea level rise of up to four metres. Hundreds of millions are already at risk from coastal flooding.

Timescale controlled

The Greenland ice sheet is melting at an accelerating rate, and once past a critical threshold could lose enough water to raise sea levels by seven metres. Even a 1.5°C warming might condemn Greenland to irreversible melting – and on present form the world could warm by 1.5°C by 2030.

“Thus we might have already committed future generations to living with sea level rises of around 10m over thousands of years. But the timescale is still under our control,” the authors warn.

They also warn that a “staggering 99% of tropical corals” could be lost if the planet heats by even 2°C – at a profound cost to both marine sea life and human economies.

They say 17% of the Amazon rainforest has been lost since 1970: a loss of somewhere between 20% and 40% could tip the entire rainforest into a destabilised state, increasingly at risk from drought and fire.

Risks multiply

In the boreal forests of northern Asia, Europe and Canada, insect outbreaks, fire and dieback could turn some regions into sources of more carbon, rather than sinks that soak up the extra carbon dioxide.

Permafrost thaw could release ever-greater volumes of stored methane, a greenhouse gas 30 times more potent, over a century, than carbon dioxide, and so on. The dangers multiply, and each one amplifies planetary heating.

“If damaging tipping cascades can occur and a global tipping point cannot be ruled out, then this is an existential threat to civilisation,” the authors warn.

“The stability and resilience of our planet is in peril. International action – not just words – must reflect this.” – Climate News Network