Category Archives: Oceans

New land height metric raises sea level rise risk

Millions of us now live in danger: we could be at risk from future high tides and winds, says a new approach to measuring land height.

 

LONDON, 4 November, 2019 – Researchers have taken a closer look at estimates of coastal land height – and found that the numbers of people already at risk from sea level rise driven by global heating have multiplied threefold.

More than 100 million people already live below the high tide line, and 250 million live on plains that are lower than the current annual flood heights. Previous estimates have put these numbers at 28 million, and 65 million.

And even if the world takes immediate drastic action and reduces greenhouse gas emissions by the end of the century, at least 190 million people will find themselves below sea level.

If the world’s nations continue on the notorious business-as-usual track and go on burning ever greater volumes of fossil fuels, then around 630 million will, by the year 2100, find themselves on land that will be below the expected annual flood levels.

Protection in question

“These assessments show the potential of climate change to reshape cities, economies, coastlines and entire global regions within our lifetime,” said Scott Kulp of Climate Central, who led a study published in the journal Nature Communications.

“As the tideline rises higher than the ground people call home, nations will increasingly confront questions about whether, how much, and how long coastal defences can protect them.”

At the heart of the new research is a revised estimate of what constitutes sea level, and how it should be measured. Individuals and communities find out the hard way how the highest tides can rise to poison their farmlands with salt and wash away the foundations of their homes.

But the big picture – across nations and regions worldwide – is harder to estimate: for decades researchers have relied on satellite readings, confirmed by flights over limited spaces with radar equipment.

“There is still a great need for . . . more accurate elevation data. Lives and livelihoods depend on it”

But space-based readings by Nasa’s radar topography programme tend to be over-estimates, the researchers argue. That is because the technology measures the height of the first reflecting surface the radar signal touches. In open country, this may not matter. But forests and high buildings in densely-peopled cities distort the picture.

In parts of coastal Australia, and using a new approach, the researchers found that satellite readings delivered over-estimates of 2.5 metres. So global averages in the past have over-estimated, by around 2 metres, the elevation of lands that are home to billions.

Research of this kind helps clarify the challenge that faces governments, civic authorities and private citizens: communities grow up along low-lying coasts and estuaries because these provide good land, reliable water supplies and easy transport. But the catch with flood plains is that, sooner or later, they flood.

The repeated evidence of a decade of climate science is that floods will become more devastating, more frequent and more prolonged for a mix of reasons.

Multiple risks

Soils will subside because of the growing demand for groundwater and for clays and stone for bricks and mortar; because global average temperatures will rise and oceans expand as they warm; glaciers will melt and tip more water into the sea to raise ocean levels; and tropical cyclones will become more intense to drive more destructive storm surges.

Researchers have already warned that sea level rise could be accelerating, to bring more flooding to, for instance, the great cities of the US coasts, while some cities can expect ever more battering from Atlantic storms.

Coastal flooding is likely to create millions of climate refugees even within the US, and the worldwide costs of coastal flooding could reach $1 trillion a year by the end of the century.

The latest study confirms that the hazards are real, and may have so far been under-estimated. The researchers calculated that, in parts of China, Bangladesh, India, Vietnam and Thailand, places now home to 237 million people could face coastal flooding every year by 2050 – a figure 183 million higher than previous estimates.

US coasts threatened

The same study highlights faulty estimates of ground elevation even in the richest and most advanced nations. In some parts of the crowded coastal cities of New York, Boston and Miami, for instance, the researchers believe satellite readings have over-estimated ground height by almost five metres. They say their new approach reduces the margin of error to 2.5 cms.

Right now, around a billion people live on lands less than 10 metres above high tide levels. Around 250 million live within one metre above high tide.

“For all of the critical research that’s been done on climate change and sea level projections, it turns out that for most of the global coast we didn’t know the height of the ground beneath our feet,” said Benjamin Strauss, president and chief scientist of Climate Central, and co-author.

“Our data improves the picture, but there is still a great need for governments and insurance companies to produce and release more accurate elevation data. Lives and livelihoods depend on it.” – Climate News Network

Millions of us now live in danger: we could be at risk from future high tides and winds, says a new approach to measuring land height.

 

LONDON, 4 November, 2019 – Researchers have taken a closer look at estimates of coastal land height – and found that the numbers of people already at risk from sea level rise driven by global heating have multiplied threefold.

More than 100 million people already live below the high tide line, and 250 million live on plains that are lower than the current annual flood heights. Previous estimates have put these numbers at 28 million, and 65 million.

And even if the world takes immediate drastic action and reduces greenhouse gas emissions by the end of the century, at least 190 million people will find themselves below sea level.

If the world’s nations continue on the notorious business-as-usual track and go on burning ever greater volumes of fossil fuels, then around 630 million will, by the year 2100, find themselves on land that will be below the expected annual flood levels.

Protection in question

“These assessments show the potential of climate change to reshape cities, economies, coastlines and entire global regions within our lifetime,” said Scott Kulp of Climate Central, who led a study published in the journal Nature Communications.

“As the tideline rises higher than the ground people call home, nations will increasingly confront questions about whether, how much, and how long coastal defences can protect them.”

At the heart of the new research is a revised estimate of what constitutes sea level, and how it should be measured. Individuals and communities find out the hard way how the highest tides can rise to poison their farmlands with salt and wash away the foundations of their homes.

But the big picture – across nations and regions worldwide – is harder to estimate: for decades researchers have relied on satellite readings, confirmed by flights over limited spaces with radar equipment.

“There is still a great need for . . . more accurate elevation data. Lives and livelihoods depend on it”

But space-based readings by Nasa’s radar topography programme tend to be over-estimates, the researchers argue. That is because the technology measures the height of the first reflecting surface the radar signal touches. In open country, this may not matter. But forests and high buildings in densely-peopled cities distort the picture.

In parts of coastal Australia, and using a new approach, the researchers found that satellite readings delivered over-estimates of 2.5 metres. So global averages in the past have over-estimated, by around 2 metres, the elevation of lands that are home to billions.

Research of this kind helps clarify the challenge that faces governments, civic authorities and private citizens: communities grow up along low-lying coasts and estuaries because these provide good land, reliable water supplies and easy transport. But the catch with flood plains is that, sooner or later, they flood.

The repeated evidence of a decade of climate science is that floods will become more devastating, more frequent and more prolonged for a mix of reasons.

Multiple risks

Soils will subside because of the growing demand for groundwater and for clays and stone for bricks and mortar; because global average temperatures will rise and oceans expand as they warm; glaciers will melt and tip more water into the sea to raise ocean levels; and tropical cyclones will become more intense to drive more destructive storm surges.

Researchers have already warned that sea level rise could be accelerating, to bring more flooding to, for instance, the great cities of the US coasts, while some cities can expect ever more battering from Atlantic storms.

Coastal flooding is likely to create millions of climate refugees even within the US, and the worldwide costs of coastal flooding could reach $1 trillion a year by the end of the century.

The latest study confirms that the hazards are real, and may have so far been under-estimated. The researchers calculated that, in parts of China, Bangladesh, India, Vietnam and Thailand, places now home to 237 million people could face coastal flooding every year by 2050 – a figure 183 million higher than previous estimates.

US coasts threatened

The same study highlights faulty estimates of ground elevation even in the richest and most advanced nations. In some parts of the crowded coastal cities of New York, Boston and Miami, for instance, the researchers believe satellite readings have over-estimated ground height by almost five metres. They say their new approach reduces the margin of error to 2.5 cms.

Right now, around a billion people live on lands less than 10 metres above high tide levels. Around 250 million live within one metre above high tide.

“For all of the critical research that’s been done on climate change and sea level projections, it turns out that for most of the global coast we didn’t know the height of the ground beneath our feet,” said Benjamin Strauss, president and chief scientist of Climate Central, and co-author.

“Our data improves the picture, but there is still a great need for governments and insurance companies to produce and release more accurate elevation data. Lives and livelihoods depend on it.” – Climate News Network

Waste plastic can find a useful new life

Here’s what to do with all that waste plastic, the scrap, waste and flotsam: turn it back into brand-new plastic and use it again, and again.

LONDON, 1 November, 2019 – Swedish scientists say they have found a way to recycle plastic perfectly: their new process can turn any waste plastic back into new plastic of identical quality – and recover all of it.

The process can convert thrown-away plastic bottles, cups, bags, buckets and other detritus into a gas and, from that, fashion new materials. That is, complete recycling would be possible from existing, no-longer-wanted materials rather than petrochemical feedstock.

In 2015, the world generated more than 320 million tonnes of polystyrene, polyvinyl chloride, polyethylene and other polymers. Perhaps 200 million tonnes was neither incinerated nor recycled. As much as 12 million tonnes may have escaped into the oceans. No more than 14% was collected for recovery. Only 2% could be converted to a high-quality product, and 8% became plastic of lower quality. Around 4% was lost altogether.

“We should not forget that plastic is a fantastic material – it gives us products that we could otherwise only dream of. The problem is that it is manufactured at such low cost that it has been cheaper to produce new plastics from oil and fossil gas than reusing plastic waste,” said Henrik Thunman of Chalmers University of Technology in Gothenburg, who with colleagues developed a way of “cracking” plastic with steam.

“Through finding the right temperature – which is around 850°C – and the right heating rate and residence time, we have been able to demonstrate the proposed method at a scale where we can turn 200kg of plastic waste an hour into a useful gas mixture. This can then be recycled at the molecular level to become new plastic materials of virgin quality.”

“Circular use would help give used plastics a true value, and thus an economic impetus for collecting it anywhere on Earth”

Professor Thunman and his fellow researchers report in the journal Sustainable Materials and Technologies that their process could be designed and integrated into existing petrochemical plants, and scaled up a hundredfold or more, ultimately to transform them into tomorrow’s recycling refineries.

It would work for all plastic waste, including detritus swept up by the tide, or unearthed from landfill.

Plastic is likely to be the enduring legacy of human occupation of the planet. Long after the species is extinguished, seemingly indestructible polymer evidence will endure in the rock strata to mark the Anthropocene, the human epoch.

Plastic waste pollution has been identified as a growing international  challenge and the polymers, sometimes in microparticle form, are finding their way to every part of the planet, and into the tissues of the great marine animals.

Creating a market

About 40% of global plastic waste in 2015 was collected in some form for incineration; about 60% was “disposed of”. Around 1% leaked into the natural world, to add to the threat to living things.

The latest demonstration of laboratory ingenuity from researchers determined to confront the Anthropocene challenge promises the possibility of a circular economy for the plastic that exists already.

“Circular use would help give used plastics a true value, and thus an economic impetus for collecting it anywhere on Earth,” said Professor Thunman.

“In turn, this would help minimise the release of plastic into nature, and create a market for collection of plastic that has already polluted the natural environment.” – Climate News Network

Here’s what to do with all that waste plastic, the scrap, waste and flotsam: turn it back into brand-new plastic and use it again, and again.

LONDON, 1 November, 2019 – Swedish scientists say they have found a way to recycle plastic perfectly: their new process can turn any waste plastic back into new plastic of identical quality – and recover all of it.

The process can convert thrown-away plastic bottles, cups, bags, buckets and other detritus into a gas and, from that, fashion new materials. That is, complete recycling would be possible from existing, no-longer-wanted materials rather than petrochemical feedstock.

In 2015, the world generated more than 320 million tonnes of polystyrene, polyvinyl chloride, polyethylene and other polymers. Perhaps 200 million tonnes was neither incinerated nor recycled. As much as 12 million tonnes may have escaped into the oceans. No more than 14% was collected for recovery. Only 2% could be converted to a high-quality product, and 8% became plastic of lower quality. Around 4% was lost altogether.

“We should not forget that plastic is a fantastic material – it gives us products that we could otherwise only dream of. The problem is that it is manufactured at such low cost that it has been cheaper to produce new plastics from oil and fossil gas than reusing plastic waste,” said Henrik Thunman of Chalmers University of Technology in Gothenburg, who with colleagues developed a way of “cracking” plastic with steam.

“Through finding the right temperature – which is around 850°C – and the right heating rate and residence time, we have been able to demonstrate the proposed method at a scale where we can turn 200kg of plastic waste an hour into a useful gas mixture. This can then be recycled at the molecular level to become new plastic materials of virgin quality.”

“Circular use would help give used plastics a true value, and thus an economic impetus for collecting it anywhere on Earth”

Professor Thunman and his fellow researchers report in the journal Sustainable Materials and Technologies that their process could be designed and integrated into existing petrochemical plants, and scaled up a hundredfold or more, ultimately to transform them into tomorrow’s recycling refineries.

It would work for all plastic waste, including detritus swept up by the tide, or unearthed from landfill.

Plastic is likely to be the enduring legacy of human occupation of the planet. Long after the species is extinguished, seemingly indestructible polymer evidence will endure in the rock strata to mark the Anthropocene, the human epoch.

Plastic waste pollution has been identified as a growing international  challenge and the polymers, sometimes in microparticle form, are finding their way to every part of the planet, and into the tissues of the great marine animals.

Creating a market

About 40% of global plastic waste in 2015 was collected in some form for incineration; about 60% was “disposed of”. Around 1% leaked into the natural world, to add to the threat to living things.

The latest demonstration of laboratory ingenuity from researchers determined to confront the Anthropocene challenge promises the possibility of a circular economy for the plastic that exists already.

“Circular use would help give used plastics a true value, and thus an economic impetus for collecting it anywhere on Earth,” said Professor Thunman.

“In turn, this would help minimise the release of plastic into nature, and create a market for collection of plastic that has already polluted the natural environment.” – Climate News Network

Rugby stars are losing their Pacific islands

Whatever happens on the pitches, rugby stars from the Pacific islands face a battle back home to save their ancestral lands from rising sea levels.

LONDON, 1 October, 2019 – Players from the Pacific islands are performing a prominent role in the intense battles at present going on at the rugby world cup in Japan.

Away from the rough and tumble on the pitch, the players are facing an even bigger challenge back home as their island nations come under increasing threat from climate change, in particular from ever-rising sea levels.

A recent report by the Intergovernmental Panel on Climate Change (IPCC) warns of the catastrophic effect rising sea levels – mainly caused by the melting of ice at the poles – will have on billions of people living in coastal areas and in island states around the world.

In the low-lying island nations of the Pacific, climate change is already having an impact. Coastal communities are frequently inundated by rising seas. Salty seawater poisons precious supplies of fresh water.

Crops are lost and homes damaged. Warming seas are killing off coral reefs, a key source of fish and an industry on which many islanders depend for their living.

Exploited

A report by the charity Christian Aid, focusing on the rugby world cup, says that while Pacific island teams Fiji, Tonga and Samoa are playing a central role in the tournament in Japan, they are, at the same time, being exploited and harmed by the actions of bigger and richer nations involved, including Australia, New Zealand and England.

The report points out that Pacific island states are among the lowest emitters of climate-changing carbon dioxide and other greenhouse gases. Yet they are among those suffering most from a warming world.

Samoa emits 0.7 tonnes of CO2 per capita each year. The equivalent figure for Australia is 16.5 tonnes and for host Japan is 10.4 tonnes.

Jonny Fa’amatuainu is a former Samoan international who has also played for rugby clubs in England, Wales and Japan.

“As a Pacific Island rugby player, tackling the climate crisis is close to my heart. My grandparents and other families who lived in a village on the coast of Samoa moved inland two years ago because of climate change”, he says.

“The island nations in the Pacific are some of the most vulnerable in the world and they have done almost nothing to cause their plight”

“The Pacific Islands are the soul of our sport and we have produced some of the most dynamic and exciting players on the planet … climate change is a crisis these countries did not cause yet it’s a fight they are suffering from the most.

“It’s a fight they need the help of the rugby community to win.”

The Christian Aid report says climate change threatens to undermine the Pacific Islands’ economies. Tourists will stop visiting and young people will be forced to leave, with up to 1.7 million likely to move from their homes in the region over the next 30 years.

Cyclone Gita, which devastated many parts of Tonga last year, was the strongest storm to hit the nation since records began. The report says global warming means such storms will be more frequent across the region in the years ahead.

The study also highlights the way in which many Pacific island rugby players are treated, being paid wages only a fraction of those earned by their counterparts in richer countries. The teams are also often excluded from various international tournaments.

Foot-dragging

“Climate change is the ultimate injustice issue and nowhere is that captured more clearly than among the nations taking part in the rugby world cup”, says Katherine Kramer of Christian Aid, the author of the report.

“The island nations in the Pacific are some of the most vulnerable in the world and they have done almost nothing to cause their plight.

“The main culprits for causing the climate crisis are European nations as well as major coal burners like Australia, the US and Japan.

“Not only have they caused the current dire situation, but they are dragging their feet on making the needed transition to a zero-carbon economy.” – Climate News Network

Whatever happens on the pitches, rugby stars from the Pacific islands face a battle back home to save their ancestral lands from rising sea levels.

LONDON, 1 October, 2019 – Players from the Pacific islands are performing a prominent role in the intense battles at present going on at the rugby world cup in Japan.

Away from the rough and tumble on the pitch, the players are facing an even bigger challenge back home as their island nations come under increasing threat from climate change, in particular from ever-rising sea levels.

A recent report by the Intergovernmental Panel on Climate Change (IPCC) warns of the catastrophic effect rising sea levels – mainly caused by the melting of ice at the poles – will have on billions of people living in coastal areas and in island states around the world.

In the low-lying island nations of the Pacific, climate change is already having an impact. Coastal communities are frequently inundated by rising seas. Salty seawater poisons precious supplies of fresh water.

Crops are lost and homes damaged. Warming seas are killing off coral reefs, a key source of fish and an industry on which many islanders depend for their living.

Exploited

A report by the charity Christian Aid, focusing on the rugby world cup, says that while Pacific island teams Fiji, Tonga and Samoa are playing a central role in the tournament in Japan, they are, at the same time, being exploited and harmed by the actions of bigger and richer nations involved, including Australia, New Zealand and England.

The report points out that Pacific island states are among the lowest emitters of climate-changing carbon dioxide and other greenhouse gases. Yet they are among those suffering most from a warming world.

Samoa emits 0.7 tonnes of CO2 per capita each year. The equivalent figure for Australia is 16.5 tonnes and for host Japan is 10.4 tonnes.

Jonny Fa’amatuainu is a former Samoan international who has also played for rugby clubs in England, Wales and Japan.

“As a Pacific Island rugby player, tackling the climate crisis is close to my heart. My grandparents and other families who lived in a village on the coast of Samoa moved inland two years ago because of climate change”, he says.

“The island nations in the Pacific are some of the most vulnerable in the world and they have done almost nothing to cause their plight”

“The Pacific Islands are the soul of our sport and we have produced some of the most dynamic and exciting players on the planet … climate change is a crisis these countries did not cause yet it’s a fight they are suffering from the most.

“It’s a fight they need the help of the rugby community to win.”

The Christian Aid report says climate change threatens to undermine the Pacific Islands’ economies. Tourists will stop visiting and young people will be forced to leave, with up to 1.7 million likely to move from their homes in the region over the next 30 years.

Cyclone Gita, which devastated many parts of Tonga last year, was the strongest storm to hit the nation since records began. The report says global warming means such storms will be more frequent across the region in the years ahead.

The study also highlights the way in which many Pacific island rugby players are treated, being paid wages only a fraction of those earned by their counterparts in richer countries. The teams are also often excluded from various international tournaments.

Foot-dragging

“Climate change is the ultimate injustice issue and nowhere is that captured more clearly than among the nations taking part in the rugby world cup”, says Katherine Kramer of Christian Aid, the author of the report.

“The island nations in the Pacific are some of the most vulnerable in the world and they have done almost nothing to cause their plight.

“The main culprits for causing the climate crisis are European nations as well as major coal burners like Australia, the US and Japan.

“Not only have they caused the current dire situation, but they are dragging their feet on making the needed transition to a zero-carbon economy.” – Climate News Network

Seabed carbon storage may help in climate crisis

The Blue Planet hasn’t been considered as a solution to the climate crisis. Three scientists advocate a sea change in global thinking: seabed carbon storage.

LONDON, 27 September, 2019 – Climate scientists say seabed carbon storage could be a new ally to help reduce greenhouse gas emissions by a volume greater than all the carbon dioxide pumped into the atmosphere from the planet’s coal-burning power stations.

It is the biggest ally possible: the 70% of the globe covered by ocean.

In a detailed argument in the journal Science, Ove Hoegh-Guldberg of the University of Queensland, Eliza Northrop of the World Resources Institute in Washington DC and Jane Lubchenco of Oregon State University outline five areas of action that could mitigate potentially calamitous climate change driven by profligate use of fossil fuels.

These include renewable energy, shipping and transport, protection of marine and coastal ecosystems, fisheries and aquaculture and – perhaps in future – carbon storage on the sea bed.

“Make no mistake: these actions are ambitious, but we argue they are necessary, could pay major dividends towards closing the emissions gap in coming decades, and achieve other co-benefits along the way”, they write.

“For far too long, the ocean has been mostly absent from policy discussions about reducing carbon emissions and meeting the challenges of climate change”

The argument was deliberately timed to coincide with a major new report by the Intergovernmental Panel on Climate Change on the oceans and the cryosphere.

If the world’s nations pursue ocean policy ambitions in the right way, they could reduce global greenhouse gas emissions by up to 4 billion tonnes of CO2 equivalent by 2030 and up to 11 billion by 2050.

And this could tot up to 21% of the reductions required in 2050 to limit warming to the declared 1.5°C target favoured at the Paris climate summit in 2015, and up to a fourth of all emissions for the formal 2°C target identified in the agreement.

“Reductions of this magnitude are larger than the annual emissions from all current coal-fired power plants worldwide,” they argue.

The first step is to set clear national targets for getting renewable energy from the restless seas, in terms of offshore wind, tidal and wave energy,  by 2030 and then by 2050.

Other benefits

Then the trio want nations to think about ways to reduce or eliminate carbon from the world’s shipping fleets. That means alternative fuels and a revolution in shore-based supply chains. Fuel efficiency in existing technologies could be improved, and hybrid power systems – including fuel cells and battery technologies – should be explored.

And, they point out, the sea itself is a carbon consumer. Mangrove swamps, seagrass meadows and salt marshes could be considered as “blue carbon ecosystems” in the way that terrestrial forests are considered “sinks” for atmospheric carbon.

These coastal and submarine “forests” make up only1.5% of the area of the land-based forests and woodlands, but their loss and degradation are equivalent to 8.4% of carbon emissions from terrestrial forests now being destroyed by human intrusion. So it would pay to restore and protect such marine habitats.

There would be other benefits: harvested seaweed could be turned into food, cattle feed, fertiliser, biofuels and bioplastics. Some seaweeds could help in even more dramatic ways.

Experiments with a red alga called Asparagopsis taxiformis, they say, “can reduce methane emissions from ruminants by up to 99% when constituting only 2% of the feed, and several other common species show potential methane reductions of 33 to 50%.”

‘Daunting’ change needed

The scientists urge a diet shift towards fish and seafood in pursuit of sustainable low-carbon protein; they also want to see the fishing industry worldwide pursue lower emissions while optimising the sustainable global catch.

“Such large-scale shifts in food policy and behaviour are daunting,” they concede. But there would be considerable climate benefits.

And, they admit, there are “considerable challenges” to the idea that carbon dioxide captured at source could be safely and cheaply stored on the seabed for many thousands of years. But they say “the theoretical potential” is very high.

“For far too long, the ocean has been mostly absent from policy discussions about reducing carbon emissions and meeting the challenges of climate change,” they conclude.

“Ocean-based actions provide increased hope that reaching the 1.5°C target might be possible, along with addressing other societal challenges, including economic development, food security and coastal community resilience.” – Climate News Network

The Blue Planet hasn’t been considered as a solution to the climate crisis. Three scientists advocate a sea change in global thinking: seabed carbon storage.

LONDON, 27 September, 2019 – Climate scientists say seabed carbon storage could be a new ally to help reduce greenhouse gas emissions by a volume greater than all the carbon dioxide pumped into the atmosphere from the planet’s coal-burning power stations.

It is the biggest ally possible: the 70% of the globe covered by ocean.

In a detailed argument in the journal Science, Ove Hoegh-Guldberg of the University of Queensland, Eliza Northrop of the World Resources Institute in Washington DC and Jane Lubchenco of Oregon State University outline five areas of action that could mitigate potentially calamitous climate change driven by profligate use of fossil fuels.

These include renewable energy, shipping and transport, protection of marine and coastal ecosystems, fisheries and aquaculture and – perhaps in future – carbon storage on the sea bed.

“Make no mistake: these actions are ambitious, but we argue they are necessary, could pay major dividends towards closing the emissions gap in coming decades, and achieve other co-benefits along the way”, they write.

“For far too long, the ocean has been mostly absent from policy discussions about reducing carbon emissions and meeting the challenges of climate change”

The argument was deliberately timed to coincide with a major new report by the Intergovernmental Panel on Climate Change on the oceans and the cryosphere.

If the world’s nations pursue ocean policy ambitions in the right way, they could reduce global greenhouse gas emissions by up to 4 billion tonnes of CO2 equivalent by 2030 and up to 11 billion by 2050.

And this could tot up to 21% of the reductions required in 2050 to limit warming to the declared 1.5°C target favoured at the Paris climate summit in 2015, and up to a fourth of all emissions for the formal 2°C target identified in the agreement.

“Reductions of this magnitude are larger than the annual emissions from all current coal-fired power plants worldwide,” they argue.

The first step is to set clear national targets for getting renewable energy from the restless seas, in terms of offshore wind, tidal and wave energy,  by 2030 and then by 2050.

Other benefits

Then the trio want nations to think about ways to reduce or eliminate carbon from the world’s shipping fleets. That means alternative fuels and a revolution in shore-based supply chains. Fuel efficiency in existing technologies could be improved, and hybrid power systems – including fuel cells and battery technologies – should be explored.

And, they point out, the sea itself is a carbon consumer. Mangrove swamps, seagrass meadows and salt marshes could be considered as “blue carbon ecosystems” in the way that terrestrial forests are considered “sinks” for atmospheric carbon.

These coastal and submarine “forests” make up only1.5% of the area of the land-based forests and woodlands, but their loss and degradation are equivalent to 8.4% of carbon emissions from terrestrial forests now being destroyed by human intrusion. So it would pay to restore and protect such marine habitats.

There would be other benefits: harvested seaweed could be turned into food, cattle feed, fertiliser, biofuels and bioplastics. Some seaweeds could help in even more dramatic ways.

Experiments with a red alga called Asparagopsis taxiformis, they say, “can reduce methane emissions from ruminants by up to 99% when constituting only 2% of the feed, and several other common species show potential methane reductions of 33 to 50%.”

‘Daunting’ change needed

The scientists urge a diet shift towards fish and seafood in pursuit of sustainable low-carbon protein; they also want to see the fishing industry worldwide pursue lower emissions while optimising the sustainable global catch.

“Such large-scale shifts in food policy and behaviour are daunting,” they concede. But there would be considerable climate benefits.

And, they admit, there are “considerable challenges” to the idea that carbon dioxide captured at source could be safely and cheaply stored on the seabed for many thousands of years. But they say “the theoretical potential” is very high.

“For far too long, the ocean has been mostly absent from policy discussions about reducing carbon emissions and meeting the challenges of climate change,” they conclude.

“Ocean-based actions provide increased hope that reaching the 1.5°C target might be possible, along with addressing other societal challenges, including economic development, food security and coastal community resilience.” – Climate News Network

Global warming hot spots pass safe limit

A study says Earth’s hot spots have already warmed by more than the safe limit for avoiding dangerous climate change.

LONDON, 15 September, 2019 − By land and sea, some of the planet’s hot spots are already above the temperature agreed by scientists and politicians as the maximum allowable to prevent a disastrous climate crisis.

The limit was accepted by 195 governments in the Paris Agreement, reached in 2015: it committed them to preventing the global average temperature rising by more than 2°C (3.6°F) above its pre-industrial level, and doing all they could to keep it below 1.5°C. It is making slow progress.

But a novel study, an analysis of scientific data by a leading US newspaper, says that about 10% of the Earth has already passed the 2°C level, with roughly twice as many hot spots above the 1.5°C mark.

The analysis, by journalists on the Washington Post, examined four global temperature data sets, from the 1800s to the present. It found that dangerous hot spots are spreading, both on land and in the seas.

Using data from US federal scientists as well as several academic groups, the journalists find that over the past five years − the hottest on record − about 10% of the planet has exceeded warming of over 2°C, or 3.6°F. Areas that have warmed by 1.5°C are about twice as common, already beyond 20% of the Earth’s area over the last five years.

“Much more than just the Arctic has crossed this threshold. Depending on the analysis used, we see 2°C of warming in much of Europe, northern Asia, the Middle East, and in key ocean hot zones”

The writers say defining how much heating has occurred requires choosing two separate time periods to compare. They considered two pre-industrial periods − from 1850 to 1899, and from 1880 to 1899 − and what they call two “end periods”, 2014 to 2018 and 2009 to 2018.

They acknowledge that some choices clearly push more of the globe beyond 2°C, especially choosing the very warm years between 2014 and 2018. They comment: “But the lowest total we got for how much of the globe is above 2°C was about 5%. That’s still an enormous area.”

The fastest-warming part of the world is the Arctic, but they say what they found applies far more widely than the far north: “Our analysis … shows that huge swaths of the region are above 2°C − if not 3°C”, they write.

“But we also find that much more than just the Arctic has crossed this threshold. Depending on the analysis used, we see 2°C of warming in much of Europe, northern Asia, the Middle East, and in key ocean hot zones.”

The analysis shows, they say, that changes in ocean currents are creating “dramatic” hot zones. Huge ocean currents, which transport heat, salt, and nutrients around the globe, are on the move, driven by changes in winds and atmospheric circulation.

Rapid heating

And because these ocean currents are warm, when they reach new areas those areas heat up fast. This is a particular problem in the southern hemisphere, where changes have occurred in every major ocean basin, leaving distinct hotspots in the regions of the Brazil Current in the South Atlantic, the Agulhas Current in the southern Indian Ocean, and the South Pacific’s East Australian Current.

The newspaper’s analysis focuses on the Brazil Current, which shows a particularly rapid warming. But the writers say it’s not alone.

The Agulhas Current, which travels southward along the coast of south-east Africa before swinging east towards Australia, shows a warming of well above 1.5°C in many regions — and occasionally even above 2°C in some datasets and scenarios.

Scientists have been studying this change for nearly four decades, and the newspaper says it is significant. The Agulhas is now spinning off more rings of warm water that swirl into the South Atlantic, transporting heat and salt from the Indian Ocean and potentially affecting a global circulation of currents.

The analysis reports on the plight of Uruguay, where a fast-warming ocean hot spot, linked with the Brazil Current, has been associated with major disruption of marine ecosystems.

Changing catches

Clams are dying on beaches, ocean heat waves are killing fish, and algal blooms are worsening. Uruguay’s fishing fleet is now bringing up up more tropical, warm-water-loving species in its nets.

The journalists point out that while fish can swim elsewhere, that’s not always an option for other species, including humans. Some species may adjust easily − for instance, many fish swim towards cooler waters nearer the poles. But shellfish and corals have to stay put. Fishing communities depend on specific fisheries, and may not be able to move or adjust.

The Paris Agreement deals in global averages, and by definition there are exceptions to averages, in both directions. So this analysis can expect to be received with some scepticism.

But the writers are convinced that the climate crisis is happening too fast for safety, and that more of the globe will be at 2°C very soon. The Post’s method considers five- and 10-year averages to identify which regions have already eclipsed 2°C. The past five years have been especially hot so, naturally, they show more of these hot spots.

But over the long term, they say, both averages are marching steadily upward. It just takes a little while for the 10-year average to catch up. − Climate News Network

A study says Earth’s hot spots have already warmed by more than the safe limit for avoiding dangerous climate change.

LONDON, 15 September, 2019 − By land and sea, some of the planet’s hot spots are already above the temperature agreed by scientists and politicians as the maximum allowable to prevent a disastrous climate crisis.

The limit was accepted by 195 governments in the Paris Agreement, reached in 2015: it committed them to preventing the global average temperature rising by more than 2°C (3.6°F) above its pre-industrial level, and doing all they could to keep it below 1.5°C. It is making slow progress.

But a novel study, an analysis of scientific data by a leading US newspaper, says that about 10% of the Earth has already passed the 2°C level, with roughly twice as many hot spots above the 1.5°C mark.

The analysis, by journalists on the Washington Post, examined four global temperature data sets, from the 1800s to the present. It found that dangerous hot spots are spreading, both on land and in the seas.

Using data from US federal scientists as well as several academic groups, the journalists find that over the past five years − the hottest on record − about 10% of the planet has exceeded warming of over 2°C, or 3.6°F. Areas that have warmed by 1.5°C are about twice as common, already beyond 20% of the Earth’s area over the last five years.

“Much more than just the Arctic has crossed this threshold. Depending on the analysis used, we see 2°C of warming in much of Europe, northern Asia, the Middle East, and in key ocean hot zones”

The writers say defining how much heating has occurred requires choosing two separate time periods to compare. They considered two pre-industrial periods − from 1850 to 1899, and from 1880 to 1899 − and what they call two “end periods”, 2014 to 2018 and 2009 to 2018.

They acknowledge that some choices clearly push more of the globe beyond 2°C, especially choosing the very warm years between 2014 and 2018. They comment: “But the lowest total we got for how much of the globe is above 2°C was about 5%. That’s still an enormous area.”

The fastest-warming part of the world is the Arctic, but they say what they found applies far more widely than the far north: “Our analysis … shows that huge swaths of the region are above 2°C − if not 3°C”, they write.

“But we also find that much more than just the Arctic has crossed this threshold. Depending on the analysis used, we see 2°C of warming in much of Europe, northern Asia, the Middle East, and in key ocean hot zones.”

The analysis shows, they say, that changes in ocean currents are creating “dramatic” hot zones. Huge ocean currents, which transport heat, salt, and nutrients around the globe, are on the move, driven by changes in winds and atmospheric circulation.

Rapid heating

And because these ocean currents are warm, when they reach new areas those areas heat up fast. This is a particular problem in the southern hemisphere, where changes have occurred in every major ocean basin, leaving distinct hotspots in the regions of the Brazil Current in the South Atlantic, the Agulhas Current in the southern Indian Ocean, and the South Pacific’s East Australian Current.

The newspaper’s analysis focuses on the Brazil Current, which shows a particularly rapid warming. But the writers say it’s not alone.

The Agulhas Current, which travels southward along the coast of south-east Africa before swinging east towards Australia, shows a warming of well above 1.5°C in many regions — and occasionally even above 2°C in some datasets and scenarios.

Scientists have been studying this change for nearly four decades, and the newspaper says it is significant. The Agulhas is now spinning off more rings of warm water that swirl into the South Atlantic, transporting heat and salt from the Indian Ocean and potentially affecting a global circulation of currents.

The analysis reports on the plight of Uruguay, where a fast-warming ocean hot spot, linked with the Brazil Current, has been associated with major disruption of marine ecosystems.

Changing catches

Clams are dying on beaches, ocean heat waves are killing fish, and algal blooms are worsening. Uruguay’s fishing fleet is now bringing up up more tropical, warm-water-loving species in its nets.

The journalists point out that while fish can swim elsewhere, that’s not always an option for other species, including humans. Some species may adjust easily − for instance, many fish swim towards cooler waters nearer the poles. But shellfish and corals have to stay put. Fishing communities depend on specific fisheries, and may not be able to move or adjust.

The Paris Agreement deals in global averages, and by definition there are exceptions to averages, in both directions. So this analysis can expect to be received with some scepticism.

But the writers are convinced that the climate crisis is happening too fast for safety, and that more of the globe will be at 2°C very soon. The Post’s method considers five- and 10-year averages to identify which regions have already eclipsed 2°C. The past five years have been especially hot so, naturally, they show more of these hot spots.

But over the long term, they say, both averages are marching steadily upward. It just takes a little while for the 10-year average to catch up. − Climate News Network

Worse US Atlantic floods need planned retreat

Its coasts are at ever-greater risk from rising seas, and US Atlantic floods will soon force people to move. Why not start planning now?

LONDON, 3 September, 2019 − What are now considered once-in-a-hundred-years floods are on the increase in the US. Later this century, they could happen to northern coastal states every year.

And even in the more fortunate cities along the south-east Atlantic and the Gulf of Mexico coasts, the once-in-a-century floods will happen a lot more often: somewhere between every 30 years and every year.

In a second study, a team of distinguished scientists argues that the US should face the inevitable and begin to plan for a managed, strategic retreat from its own coasts.

At the heart of both studies is a set of new realities imposed by a rapidly-heating ocean and higher air temperatures worldwide. As the icecaps of Greenland and Antarctica melt, and as the glaciers of Canada and Alaska retreat, so sea levels have begun to rise inexorably.

But as the oceans increase in average temperature, thanks to an ever-warmer atmosphere driven by greenhouse gases from profligate combustion of fossil fuels, so the oceans have begun to expand: warmer waters are less dense, and thus higher.

“We need to stop picturing our relationship with nature as a war. We’re not winning or losing, we’re adjusting to changes in nature”

And there is a third factor. With warmer seas there will be more frequent and more violent hurricanes and windstorms, more damaging storm surges and yet more torrential rainfall.

Researchers from Princeton University report in the journal Nature Communications that they considered all three factors to create a flood hazard map of the US. Simply because of rising waters, New England states can expect to see what were once rare events almost every year.

“For the Gulf of Mexico, we found the effect of storm surge is compatible with or more significant than the effect of sea level rise for 40% of counties,” said Ning Lin, a Princeton engineer.

“So if we neglect the effects of storm climatology change, we would significantly underestimate the impact of climate change for these regions.”

Growing Atlantic danger

Exercises of this kind are about planning for the worst: were the Princeton research the only such study, city chiefs could afford to relax. But it is not.

For years climate scientists and oceanographers have been warning of ever-greater hazard to Atlantic America. They have warned of ever more torrential rains and the hazards of ever more damaging floods even in disparate cities such as Charleston and Seattle; they have even warned of high tide floods on a daily basis in some cities, and they have proposed that an estimated 13 million Americans could become climate refugees, driven by the advancing seas from their own homes.

All of which is why a trio of researchers argue for the need to accept the inevitable and step back from the sea, and they say so in the journal Science. They argue that the US should start to prepare for retreat by limiting development in the areas most at risk.

“Fighting the ocean is a losing battle,” said A R Siders of Harvard and the University of Delaware. “The only way to win against water is not to fight. We need to stop picturing our relationship with nature as a war. We’re not winning or losing, we’re adjusting to changes in nature.” − Climate News Network

Its coasts are at ever-greater risk from rising seas, and US Atlantic floods will soon force people to move. Why not start planning now?

LONDON, 3 September, 2019 − What are now considered once-in-a-hundred-years floods are on the increase in the US. Later this century, they could happen to northern coastal states every year.

And even in the more fortunate cities along the south-east Atlantic and the Gulf of Mexico coasts, the once-in-a-century floods will happen a lot more often: somewhere between every 30 years and every year.

In a second study, a team of distinguished scientists argues that the US should face the inevitable and begin to plan for a managed, strategic retreat from its own coasts.

At the heart of both studies is a set of new realities imposed by a rapidly-heating ocean and higher air temperatures worldwide. As the icecaps of Greenland and Antarctica melt, and as the glaciers of Canada and Alaska retreat, so sea levels have begun to rise inexorably.

But as the oceans increase in average temperature, thanks to an ever-warmer atmosphere driven by greenhouse gases from profligate combustion of fossil fuels, so the oceans have begun to expand: warmer waters are less dense, and thus higher.

“We need to stop picturing our relationship with nature as a war. We’re not winning or losing, we’re adjusting to changes in nature”

And there is a third factor. With warmer seas there will be more frequent and more violent hurricanes and windstorms, more damaging storm surges and yet more torrential rainfall.

Researchers from Princeton University report in the journal Nature Communications that they considered all three factors to create a flood hazard map of the US. Simply because of rising waters, New England states can expect to see what were once rare events almost every year.

“For the Gulf of Mexico, we found the effect of storm surge is compatible with or more significant than the effect of sea level rise for 40% of counties,” said Ning Lin, a Princeton engineer.

“So if we neglect the effects of storm climatology change, we would significantly underestimate the impact of climate change for these regions.”

Growing Atlantic danger

Exercises of this kind are about planning for the worst: were the Princeton research the only such study, city chiefs could afford to relax. But it is not.

For years climate scientists and oceanographers have been warning of ever-greater hazard to Atlantic America. They have warned of ever more torrential rains and the hazards of ever more damaging floods even in disparate cities such as Charleston and Seattle; they have even warned of high tide floods on a daily basis in some cities, and they have proposed that an estimated 13 million Americans could become climate refugees, driven by the advancing seas from their own homes.

All of which is why a trio of researchers argue for the need to accept the inevitable and step back from the sea, and they say so in the journal Science. They argue that the US should start to prepare for retreat by limiting development in the areas most at risk.

“Fighting the ocean is a losing battle,” said A R Siders of Harvard and the University of Delaware. “The only way to win against water is not to fight. We need to stop picturing our relationship with nature as a war. We’re not winning or losing, we’re adjusting to changes in nature.” − Climate News Network

Ocean heat waves damage reefs and kill coral

Heat extremes on land can kill. Ocean heat waves can devastate coral reefs and other ecosystems – and these too are on the increase.

LONDON, 12 August, 2019 − Heat extremes on the high seas are on the increase, with ocean heat waves disturbing ecosystems in two hemispheres and two great oceans, US scientists report.

And these same sudden rises in sea temperatures don’t just damage coral reefs, they kill the corals and start the process of reef decay, according to a separate study by Australian researchers.

Andrew Pershing of the Gulf of Maine Research Institute and colleagues report in the Proceedings of the National Academy of Sciences that they examined data from 65 marine ecosystems over the years 1854 to 2018 to work out how frequently ocean temperatures suddenly rose to unexpected levels.

They found such deviations from the average in the Arctic, North Atlantic, eastern Pacific and off the Australian coasts. They expected to find evidence of occasional hot flushes. But they did not expect to find quite so many.

“Severe marine heatwave events can have a far more severe impact than coral bleaching – the animal dies and its underlying skeleton is all that remains”

“Across the 65 ecosystems we examined, we expected about six or seven of them would experience these ‘surprises’ each year,” Dr Pershing said. “Instead, we’ve seen an average of 12 ecosystems experiencing these warming events each year over the past seven years, including a high of 23 ‘surprises’ in 2016.”

Intense and sudden changes in sea temperatures affect crustaceans, algae, corals, molluscs and many millions of humans who depend on the oceans for income. And a new study by researchers from Australian universities reports that even a rise of 0.5°C is reflected in deaths during an outbreak of coral bleaching.

Corals live in symbiosis with algae: ocean warming periodically disturbs this normally beneficial relationship. The coral animals evert (turn out) the algae and once-lurid reefs will bleach, and become more vulnerable to disease.

Corals support the world’s richest ocean ecosystems so such changes are a challenge, both to the survival of biodiversity and to local incomes from the tourism linked to the beauty of the reefs.

Very warm water

“What we are seeing is that severe marine heatwave events can have a far more severe impact than coral bleaching: the water temperatures are so warm that that the coral animal doesn’t bleach – in terms of a loss of its symbiosis – the animal dies and its underlying skeleton is all that remains,” said Tracy Ainsworth of the University of New South Wales.

The researchers report in the journal Current Biology that they used computer tomography scanning techniques to explore the marine destruction. In 2016, more than 30% of the northern part of Australia’s Great Barrier Reef experienced temperatures higher than those in which corals can survive.

“We find that the skeleton is immediately overgrown by rapid growth of algae and bacteria,” said Bill Leggat of the University of Newcastle, a co-author.

“We show that this process is devastating not just for the animal tissue but also for the skeleton that is left behind, which is rapidly eroded and weakened.” − Climate News Network

Heat extremes on land can kill. Ocean heat waves can devastate coral reefs and other ecosystems – and these too are on the increase.

LONDON, 12 August, 2019 − Heat extremes on the high seas are on the increase, with ocean heat waves disturbing ecosystems in two hemispheres and two great oceans, US scientists report.

And these same sudden rises in sea temperatures don’t just damage coral reefs, they kill the corals and start the process of reef decay, according to a separate study by Australian researchers.

Andrew Pershing of the Gulf of Maine Research Institute and colleagues report in the Proceedings of the National Academy of Sciences that they examined data from 65 marine ecosystems over the years 1854 to 2018 to work out how frequently ocean temperatures suddenly rose to unexpected levels.

They found such deviations from the average in the Arctic, North Atlantic, eastern Pacific and off the Australian coasts. They expected to find evidence of occasional hot flushes. But they did not expect to find quite so many.

“Severe marine heatwave events can have a far more severe impact than coral bleaching – the animal dies and its underlying skeleton is all that remains”

“Across the 65 ecosystems we examined, we expected about six or seven of them would experience these ‘surprises’ each year,” Dr Pershing said. “Instead, we’ve seen an average of 12 ecosystems experiencing these warming events each year over the past seven years, including a high of 23 ‘surprises’ in 2016.”

Intense and sudden changes in sea temperatures affect crustaceans, algae, corals, molluscs and many millions of humans who depend on the oceans for income. And a new study by researchers from Australian universities reports that even a rise of 0.5°C is reflected in deaths during an outbreak of coral bleaching.

Corals live in symbiosis with algae: ocean warming periodically disturbs this normally beneficial relationship. The coral animals evert (turn out) the algae and once-lurid reefs will bleach, and become more vulnerable to disease.

Corals support the world’s richest ocean ecosystems so such changes are a challenge, both to the survival of biodiversity and to local incomes from the tourism linked to the beauty of the reefs.

Very warm water

“What we are seeing is that severe marine heatwave events can have a far more severe impact than coral bleaching: the water temperatures are so warm that that the coral animal doesn’t bleach – in terms of a loss of its symbiosis – the animal dies and its underlying skeleton is all that remains,” said Tracy Ainsworth of the University of New South Wales.

The researchers report in the journal Current Biology that they used computer tomography scanning techniques to explore the marine destruction. In 2016, more than 30% of the northern part of Australia’s Great Barrier Reef experienced temperatures higher than those in which corals can survive.

“We find that the skeleton is immediately overgrown by rapid growth of algae and bacteria,” said Bill Leggat of the University of Newcastle, a co-author.

“We show that this process is devastating not just for the animal tissue but also for the skeleton that is left behind, which is rapidly eroded and weakened.” − Climate News Network

Acid oceans may trigger mass extinction

A stable carbon cycle means life goes on. Too much carbon could wipe out many species. And acid oceans could hold the key.

LONDON, 23 July, 2019 − Catastrophically widespread die-offs of many creatures could be inevitable if human activities continue to lead to more acid oceans, a new study suggests.

Mass extinction may not be an enduring mystery. Instead, it may be an intrinsic property of the carbon cycle. Once levels of dissolved carbon dioxide in the oceans reach a certain threshold, life undergoes dramatic and catastrophic change.

If a US mathematician is right – and his argument is based on statistical reasoning and the evidence in the marine sediments – then once the seas become too acidic for marine organisms to form carbonate shells, a cascade of extinction begins.

And, he warns, the “unusually strong but geologically brief duration” of manmade carbon dioxide increase in the oceans can be matched with slow but devastating extinctions in the past.

In short, human combustion of fossil fuels, combined with the destruction of the forests, could be building up to extinctions on a scale so colossal that they will be visible in the fossil record hundreds of millions of years from now.

After a certain point, the carbon cycle will take over and decide life’s direction. It happened many times long before the emergence of the human species, and it could happen again, according to a new study in the  Proceedings of the National Academy of Sciences.

“It’s a positive feedback. More carbon dioxide leads to more carbon dioxide. Is such a feedback enough to render the system unstable?”

“Once we are over the threshold, how we got there may not matter,” said Daniel Rothman of the Massachusetts Institute of Technology. “Once you get over it, you’re dealing with how the Earth works, and it goes on its own ride.”

Professor Rothman developed his hypothesis in 2017, in the journal Science Advances, after he analysed 31 changes in the makeup of carbonate sediments laid down over the last 542 million years, and connected five great extinctions not just with carbon dioxide levels but with the rate at which these increased.

He may be for the moment a lone voice in linking four of the five major extinctions with critical levels of oceanic acidification as a consequence of a carbon dioxide threshold. But climate scientists and palaeontologists have been looking at possible links between carbon and extinction for decades.

They have also repeatedly warned that humans are about to precipitate a sixth mass extinction, chiefly on the basis that we are destroying natural habitat and erasing the conditions in which millions of species – many of them still not identified – were once able to flourish.

The carbon factor

But climate change driven by ever-increasing atmospheric carbon dioxide levels – powered in turn by ever-increasing combustion of fossil fuels – has also been a factor.

Whatever the risk to species or ecosystems, biologists and conservationists have warned that climate change driven by global heating can only make things worse.

And the more carefully researchers have looked at evidence of earlier catastrophic extinctions, the more bygone climate change has revealed itself. What caused the most dramatic and unequivocal of these – the “great dying” at the close of the Permian – is still hotly debated, but atmospheric conditions in one form or another have been repeatedly invoked and researchers have repeatedly drawn lessons for today.

But arguments so far have settled on whether such extinctions are a consequence of slow but inexorable episodes of volcanic discharge or some other geological shift.

Forget the trigger

Professor Rothman’s point is that the trigger itself may not be the important thing: what decides the fate of life on Earth is the level of carbon in the oceans and the rate at which it increases.

Once levels of acidification in the upper ocean reach a certain critical threshold, life is in for major disruption. If marine creatures cannot form shells, they are at risk. But even more dangerously, shells sink to the ocean floor, effectively removing carbon from circulation.

If there are fewer calcifying organisms, then less carbon dioxide is removed from the atmosphere and oceans become even more acidic. A vicious cycle has begun.

“It’s a positive feedback,” Professor Rothman said. “More carbon dioxide leads to more carbon dioxide. The question, from a mathematical point of view is, is such a feedback enough to render the system unstable?”

Balance restored

In his mathematical model, once carbon levels reached a critical threshold, a cascade of positive feedbacks amplified the effect. Severe ocean acidification set in.

The effect was not permanent. After tens of thousands of years, the carbon cycle did slip back to equilibrium and life could evolve and adapt again.

Carbon is now entering the oceans at an unprecedented rate, over what – in geological terms – is a very brief timespan. If human-triggered greenhouse gas emissions cross a critical threshold, the consequences could be as severe as any of the previous mass extinctions.

“It’s difficult to know how things will end up, given what is happening today,” he said. “But we are probably close to a critical threshold. Any spike would reach its maximum after about 10,000 years. Hopefully, that would give us time to find a solution.” − Climate News Network

A stable carbon cycle means life goes on. Too much carbon could wipe out many species. And acid oceans could hold the key.

LONDON, 23 July, 2019 − Catastrophically widespread die-offs of many creatures could be inevitable if human activities continue to lead to more acid oceans, a new study suggests.

Mass extinction may not be an enduring mystery. Instead, it may be an intrinsic property of the carbon cycle. Once levels of dissolved carbon dioxide in the oceans reach a certain threshold, life undergoes dramatic and catastrophic change.

If a US mathematician is right – and his argument is based on statistical reasoning and the evidence in the marine sediments – then once the seas become too acidic for marine organisms to form carbonate shells, a cascade of extinction begins.

And, he warns, the “unusually strong but geologically brief duration” of manmade carbon dioxide increase in the oceans can be matched with slow but devastating extinctions in the past.

In short, human combustion of fossil fuels, combined with the destruction of the forests, could be building up to extinctions on a scale so colossal that they will be visible in the fossil record hundreds of millions of years from now.

After a certain point, the carbon cycle will take over and decide life’s direction. It happened many times long before the emergence of the human species, and it could happen again, according to a new study in the  Proceedings of the National Academy of Sciences.

“It’s a positive feedback. More carbon dioxide leads to more carbon dioxide. Is such a feedback enough to render the system unstable?”

“Once we are over the threshold, how we got there may not matter,” said Daniel Rothman of the Massachusetts Institute of Technology. “Once you get over it, you’re dealing with how the Earth works, and it goes on its own ride.”

Professor Rothman developed his hypothesis in 2017, in the journal Science Advances, after he analysed 31 changes in the makeup of carbonate sediments laid down over the last 542 million years, and connected five great extinctions not just with carbon dioxide levels but with the rate at which these increased.

He may be for the moment a lone voice in linking four of the five major extinctions with critical levels of oceanic acidification as a consequence of a carbon dioxide threshold. But climate scientists and palaeontologists have been looking at possible links between carbon and extinction for decades.

They have also repeatedly warned that humans are about to precipitate a sixth mass extinction, chiefly on the basis that we are destroying natural habitat and erasing the conditions in which millions of species – many of them still not identified – were once able to flourish.

The carbon factor

But climate change driven by ever-increasing atmospheric carbon dioxide levels – powered in turn by ever-increasing combustion of fossil fuels – has also been a factor.

Whatever the risk to species or ecosystems, biologists and conservationists have warned that climate change driven by global heating can only make things worse.

And the more carefully researchers have looked at evidence of earlier catastrophic extinctions, the more bygone climate change has revealed itself. What caused the most dramatic and unequivocal of these – the “great dying” at the close of the Permian – is still hotly debated, but atmospheric conditions in one form or another have been repeatedly invoked and researchers have repeatedly drawn lessons for today.

But arguments so far have settled on whether such extinctions are a consequence of slow but inexorable episodes of volcanic discharge or some other geological shift.

Forget the trigger

Professor Rothman’s point is that the trigger itself may not be the important thing: what decides the fate of life on Earth is the level of carbon in the oceans and the rate at which it increases.

Once levels of acidification in the upper ocean reach a certain critical threshold, life is in for major disruption. If marine creatures cannot form shells, they are at risk. But even more dangerously, shells sink to the ocean floor, effectively removing carbon from circulation.

If there are fewer calcifying organisms, then less carbon dioxide is removed from the atmosphere and oceans become even more acidic. A vicious cycle has begun.

“It’s a positive feedback,” Professor Rothman said. “More carbon dioxide leads to more carbon dioxide. The question, from a mathematical point of view is, is such a feedback enough to render the system unstable?”

Balance restored

In his mathematical model, once carbon levels reached a critical threshold, a cascade of positive feedbacks amplified the effect. Severe ocean acidification set in.

The effect was not permanent. After tens of thousands of years, the carbon cycle did slip back to equilibrium and life could evolve and adapt again.

Carbon is now entering the oceans at an unprecedented rate, over what – in geological terms – is a very brief timespan. If human-triggered greenhouse gas emissions cross a critical threshold, the consequences could be as severe as any of the previous mass extinctions.

“It’s difficult to know how things will end up, given what is happening today,” he said. “But we are probably close to a critical threshold. Any spike would reach its maximum after about 10,000 years. Hopefully, that would give us time to find a solution.” − Climate News Network

Arctic sea ice loss affects the jet stream

The jet stream affects northern hemisphere climates. And global warming affects the behaviour of the jet stream. Prepare for yet more extremes of seasonal weather.

LONDON, 6 June, 2019 − Did you shiver in a winter ice storm? Could you wilt in a protracted heatwave this summer? German scientists have just identified the guilty agency and delivered the evidence implicating the jet stream.

Blame it on Arctic warming, they conclude: the retreat of the sea ice over the polar ocean has distorted the pattern of flow of the stratospheric winds usually known as the jet stream.

It is not a new idea. But this time, scientists have employed artificial intelligence and a machine-learning programme to accurately model the changes in the jet stream and then link these to changes in the chemistry of the upper atmosphere, and increasing patterns of twisting waves in the high altitude winds which then distort seasonal weather in the northern hemisphere mid-latitudes. They describe their research in the journal Scientific Reports.

“Our study shows that the changes in the jet stream are at least partly due to the loss of Arctic sea ice. If the ice cover continues to dwindle, we believe that both the frequency and intensity of the extreme weather events previously observed in the middle latitudes will increase,” said Markus Rex, who heads atmospheric research at the Alfred Wegener Institute in Potsdam, Germany.

Cold bouts explained

“In addition, our findings confirm that the more frequently occurring cold phases in winter in the USA, Europe and Asia are by no means a contradiction to global warming; rather they are part of anthropogenic climate change.”

The jet stream – exploited by jet aircraft on the trans-Atlantic routes – is made up of westerly winds that, at an altitude of 10 kilometres, stream around the planet in the mid-latitudes, at speeds of up to 500 km an hour, and push weather systems from west to east.

But researchers have already observed this: they have been changing, in response to global warming and in particular to the rapid warming of the Arctic, as greenhouse gas ratios in the atmosphere rise, and go on rising, in response to profligate human combustion of fossil fuels.

Rather than stick to a course more or less parallel to the Equator, these winds have been observed describing dramatic waves.

“If the ice cover continues to dwindle, we believe that both the frequency and intensity of the extreme weather events previously observed in the middle latitudes will increase”

These twists of direction have been linked to blasts of Arctic air into regions that could normally expect relatively mild winters: in particular to the ferocious cold that hit the US Midwest in January 2019.

These winds have also weakened and been linked to prolonged drought and extremes of heat that hit Europe in 2003, 2006, 2015 and 2018.

But association is not the same as demonstration of cause-and-effect. The Potsdam scientists wanted surer evidence. And their new climate simulations now include a machine-learning component that accounts for ozone chemistry at high altitudes.

And what their new model found was that as the Arctic sea ice retreats, the atmospheric waves have warmed the polar stratosphere in ways that have been amplified by the behaviour of the ozone layer.

Ozone response

Since what powers the jet stream is the difference between the cold Arctic and the warm tropics, the jet stream has weakened, and begun to meander, like a river flowing across a flood plain towards the sea.

In effect, the new study introduces a new piece to the climate puzzle: the response of the ozone layer and its role in the play of winds around the planet. The pay-off could be a clearer picture of things to come.

“We are now for the first time employing artificial intelligence in climate modelling, helping us arrive at more realistic model systems,” said Professor Rex.

“This holds tremendous potential for future climate models, which we believe will deliver more reliable climate projections and therefore a more robust basis for political decision-making.” − Climate News Network

The jet stream affects northern hemisphere climates. And global warming affects the behaviour of the jet stream. Prepare for yet more extremes of seasonal weather.

LONDON, 6 June, 2019 − Did you shiver in a winter ice storm? Could you wilt in a protracted heatwave this summer? German scientists have just identified the guilty agency and delivered the evidence implicating the jet stream.

Blame it on Arctic warming, they conclude: the retreat of the sea ice over the polar ocean has distorted the pattern of flow of the stratospheric winds usually known as the jet stream.

It is not a new idea. But this time, scientists have employed artificial intelligence and a machine-learning programme to accurately model the changes in the jet stream and then link these to changes in the chemistry of the upper atmosphere, and increasing patterns of twisting waves in the high altitude winds which then distort seasonal weather in the northern hemisphere mid-latitudes. They describe their research in the journal Scientific Reports.

“Our study shows that the changes in the jet stream are at least partly due to the loss of Arctic sea ice. If the ice cover continues to dwindle, we believe that both the frequency and intensity of the extreme weather events previously observed in the middle latitudes will increase,” said Markus Rex, who heads atmospheric research at the Alfred Wegener Institute in Potsdam, Germany.

Cold bouts explained

“In addition, our findings confirm that the more frequently occurring cold phases in winter in the USA, Europe and Asia are by no means a contradiction to global warming; rather they are part of anthropogenic climate change.”

The jet stream – exploited by jet aircraft on the trans-Atlantic routes – is made up of westerly winds that, at an altitude of 10 kilometres, stream around the planet in the mid-latitudes, at speeds of up to 500 km an hour, and push weather systems from west to east.

But researchers have already observed this: they have been changing, in response to global warming and in particular to the rapid warming of the Arctic, as greenhouse gas ratios in the atmosphere rise, and go on rising, in response to profligate human combustion of fossil fuels.

Rather than stick to a course more or less parallel to the Equator, these winds have been observed describing dramatic waves.

“If the ice cover continues to dwindle, we believe that both the frequency and intensity of the extreme weather events previously observed in the middle latitudes will increase”

These twists of direction have been linked to blasts of Arctic air into regions that could normally expect relatively mild winters: in particular to the ferocious cold that hit the US Midwest in January 2019.

These winds have also weakened and been linked to prolonged drought and extremes of heat that hit Europe in 2003, 2006, 2015 and 2018.

But association is not the same as demonstration of cause-and-effect. The Potsdam scientists wanted surer evidence. And their new climate simulations now include a machine-learning component that accounts for ozone chemistry at high altitudes.

And what their new model found was that as the Arctic sea ice retreats, the atmospheric waves have warmed the polar stratosphere in ways that have been amplified by the behaviour of the ozone layer.

Ozone response

Since what powers the jet stream is the difference between the cold Arctic and the warm tropics, the jet stream has weakened, and begun to meander, like a river flowing across a flood plain towards the sea.

In effect, the new study introduces a new piece to the climate puzzle: the response of the ozone layer and its role in the play of winds around the planet. The pay-off could be a clearer picture of things to come.

“We are now for the first time employing artificial intelligence in climate modelling, helping us arrive at more realistic model systems,” said Professor Rex.

“This holds tremendous potential for future climate models, which we believe will deliver more reliable climate projections and therefore a more robust basis for political decision-making.” − Climate News Network

Unstable polar glaciers lose ice ever faster

As oceans warm, Antarctica’s ice sheets are at growing risk, with polar glaciers losing ice at rates to match the height of global monuments.

LONDON, 31 May, 2019 – Almost a quarter of all the glaciers in West Antarctica have been pronounced “unstable”. This means, in the simplest terms, that they are losing ice to the ocean faster than they can gain it from falling snow.

In the last 25 years most of the largest flows have accelerated the loss of ice fivefold.

And in places some glaciers, including those known as Pine Island and Thwaites, have “thinned” by 122 metres. That means that the thickness of the ice between the surface and the bedrock over which glaciers flow has fallen by almost the height of the Great Pyramid of Cheops in Egypt, and far more than the Statue of Liberty in New York or the tower of Big Ben in London.

The conclusions are based on climate simulation matched against 800 million measurements of the Antarctic ice sheet recorded by the altimeters aboard four orbiting satellites put up by the European Space Agency between 1992 and 2017. The conclusion is published in the journal Geophysical Research Letters.

“A wave of thinning has spread rapidly across some of Antarctica’s most vulnerable glaciers, and their losses are driving up sea levels around the planet”

Antarctic research is challenging. The continent is enormous – nearly twice the size of Australia – and frozen: 99.4% of it is covered by ice, to huge depths. It is also defined as a desert.

Snowfalls are low, but over millions of years these have built up to a reservoir of about nine-tenths of the planet’s fresh water, in the form of snow and ice.

It is also the coldest place on Earth and – even more of a problem for climate scientists – no observations or measurements of anything in Antarctica date back much further than the beginning of the 19th century. Most of the on-the-ground science is possible only in the Antarctic summer.

The latest study confirms a succession of alarming finds. The West Antarctic ice sheet is not just losing ice, it is doing so at ever-faster speeds. Scientists have already suggested that the rate of loss for the Pine Island and Thwaites glaciers could be irreversible. So much has already been lost that the bedrock, crushed by its burden of ice for aeons, is actually beginning to bounce up in response.

Huge ice losses

“In parts of Antarctica the ice sheet has thinned by extraordinary amounts, and we set out to show how much was due to changes in climate and how much was due to weather,” said Andrew Shepherd of the University of Leeds, UK, who led the research.

Changes in snowfall tended, they found, to be reflected over changes in height over large areas for a few years. But the most pronounced changes have persisted for decades: it’s the climate that is changing things, not the weather.

“Knowing how much snow has fallen has really helped us to detect the underlying change in glacier ice within the satellite record. We can see clearly now that a wave of thinning has spread rapidly across some of Antarctica’s most vulnerable glaciers, and their losses are driving up sea levels around the planet”, Professor Shepherd says.

“Altogether, ice losses from East and West Antarctica have contributed 4.6mm to global sea level rise since 1992.” – Climate News Network

As oceans warm, Antarctica’s ice sheets are at growing risk, with polar glaciers losing ice at rates to match the height of global monuments.

LONDON, 31 May, 2019 – Almost a quarter of all the glaciers in West Antarctica have been pronounced “unstable”. This means, in the simplest terms, that they are losing ice to the ocean faster than they can gain it from falling snow.

In the last 25 years most of the largest flows have accelerated the loss of ice fivefold.

And in places some glaciers, including those known as Pine Island and Thwaites, have “thinned” by 122 metres. That means that the thickness of the ice between the surface and the bedrock over which glaciers flow has fallen by almost the height of the Great Pyramid of Cheops in Egypt, and far more than the Statue of Liberty in New York or the tower of Big Ben in London.

The conclusions are based on climate simulation matched against 800 million measurements of the Antarctic ice sheet recorded by the altimeters aboard four orbiting satellites put up by the European Space Agency between 1992 and 2017. The conclusion is published in the journal Geophysical Research Letters.

“A wave of thinning has spread rapidly across some of Antarctica’s most vulnerable glaciers, and their losses are driving up sea levels around the planet”

Antarctic research is challenging. The continent is enormous – nearly twice the size of Australia – and frozen: 99.4% of it is covered by ice, to huge depths. It is also defined as a desert.

Snowfalls are low, but over millions of years these have built up to a reservoir of about nine-tenths of the planet’s fresh water, in the form of snow and ice.

It is also the coldest place on Earth and – even more of a problem for climate scientists – no observations or measurements of anything in Antarctica date back much further than the beginning of the 19th century. Most of the on-the-ground science is possible only in the Antarctic summer.

The latest study confirms a succession of alarming finds. The West Antarctic ice sheet is not just losing ice, it is doing so at ever-faster speeds. Scientists have already suggested that the rate of loss for the Pine Island and Thwaites glaciers could be irreversible. So much has already been lost that the bedrock, crushed by its burden of ice for aeons, is actually beginning to bounce up in response.

Huge ice losses

“In parts of Antarctica the ice sheet has thinned by extraordinary amounts, and we set out to show how much was due to changes in climate and how much was due to weather,” said Andrew Shepherd of the University of Leeds, UK, who led the research.

Changes in snowfall tended, they found, to be reflected over changes in height over large areas for a few years. But the most pronounced changes have persisted for decades: it’s the climate that is changing things, not the weather.

“Knowing how much snow has fallen has really helped us to detect the underlying change in glacier ice within the satellite record. We can see clearly now that a wave of thinning has spread rapidly across some of Antarctica’s most vulnerable glaciers, and their losses are driving up sea levels around the planet”, Professor Shepherd says.

“Altogether, ice losses from East and West Antarctica have contributed 4.6mm to global sea level rise since 1992.” – Climate News Network