Category Archives: Land Use

Rewilded farmland can save money − and the Earth

To save civilisation, try rewilded farmland. But that salvation depends on which land goes back to forest and savannah.

LONDON, 2 November, 2020 − An international consortium of scientists has worked out − once again − how to conserve life on the planet and absorb dramatic quantities of the atmospheric carbon that is driving potentially calamitous climate change: go for rewilded farmland, fields of crops and livestock returned to prairie and forest. And they have identified the most cost-effective way to do it.

Global salvation requires the world’s nations to do simply what they have already undertaken to do: restore 15% of cultivated land to natural forest, grassland, shrubland, wetland and desert ecosystem.

If such restoration happened in the highest priority zones, then almost two-thirds of the wild things now threatened with imminent extinction could survive.

And the restored wilderness that would protect them would also start absorbing atmospheric carbon at an accelerating rate: it could sequester an estimated 229 billion tonnes of the greenhouse gas carbon dioxide (CO2). This is almost a third of all the CO2 spilled into the atmosphere by coal, oil and gas combustion in the last 200 years.

All that would be possible if the world’s nations delivered on vows made 10 years ago in Japan, to restore 15% of ecosystems worldwide. If the 196 nations that signed up went further, and restored a carefully chosen 30%, they could save more than 70% of the million or so species sliding towards extinction, and absorb 465 billion tonnes of CO2: almost half of all the extra atmospheric carbon loaded into the atmosphere by human societies since the Industrial Revolution.

Two provisos

“Pushing forward on plans to return significant sweeps of nature to a natural state is critical to preventing ongoing biodiversity and climate crises from spinning out of control,” said Bernado Strassburg, of the Pontifical Catholic University in Brazil, who led the study.

“We show that if we’re smarter about where we restore nature, we can tick the climate, biodiversity and budget boxes on the world’s urgent to-do list.”

There is a catch. To be most effective, and for the lowest costs, nations would have to work together.

Right now, scientists report in the journal Nature, each nation has undertaken to restore 15% of its wilderness. But to save the greatest number of species, and absorb the highest levels of carbon, with the lowest cost to farmland and food security, humankind would have to assess the world as a whole, and restore those ecosystems that would serve the goals most effectively.

There is a second catch: barely a month ago, a UN report confirmed that although 196 nations agreed on 20 targets to protect biodiversity − to be achieved by 2020 − a decade ago, there has been “partial progress” in just six of them. The million species then threatened with extinction are still threatened.

Potential ignored

“Many good things are happening around the world and these should be celebrated and encouraged,” said Elizabeth Maruma Mrema, executive secretary of the Convention on Biological Diversity.

“Nevertheless the rate of biodiversity loss is unprecedented in human history, and pressures are intensifying. Earth’s living systems as a whole are being compromised.”

And that threat starts with the green things on which all life depends: in September, the Royal Botanic Gardens at Kew in London published a new study on ways to identify and care for the plants and fungi that underwrite survival for what could be seven million or more species alive on the planet, and more than seven billion humans.

The study, involving 210 scientists in 42 countries, said Alexandre Antonelli, director of science at the Royal Botanic Gardens, paints a picture “of a world that has turned its back on the incredible potential of plant and fungal kingdoms to address some of the biggest challenges we face.

“We have particularly earmarked the gaps in our knowledge, the changes we are seeing, the species being named new to science and the shocking pace of biodiversity loss.”

“The rate of biodiversity loss is unprecedented in human history, and pressures are intensifying. Earth’s living systems as a whole are being compromised”

The most recent finding builds on the drive not just to fulfil the obligations undertaken 10 years ago, but to identify the very best ways to fulfil them, so as to benefit the greatest number of people.

It delivers the evidence that restoration in the most carefully chosen regions would have the most profound impact: put simply, restoration could be 13 times more cost-effective if it happened in what the Nature researchers have identified as the highest priority locations.

They used sophisticated mathematical tools and detailed geographic data to take a closer look at the 28.7 million square kilometres of natural wilderness that have been converted to farmland: 54% of these were originally forest, 25% grasslands, 14% shrublands, 4% arid lands and 2% wetland.

They then tested these areas against three considerations: their value as habitat, their capacity for carbon storage and their cost-effectiveness. And they came up with recommendations that would deliver 91% of the potential benefit for plants and animals of the wilderness and 82% of the climate mitigation benefit, and reduce costs by 27%.

And then they considered the nation-by-nation approach: were each country to restore 15% of its own forests, the biodiversity boon fell by 28%, the climate benefits by 29%, while the costs would rise by 52%.

Vital partnership

They then considered the impact on the world’s food supplies, to find that 15.78 million sq kms, or 55% of wilderness converted to farmland, could be restored without squeezing food supplies, always providing nations encouraged what they call the “sustainable intensification” of farming, along with a reduction in food waste and a move away from meat and dairy products.

The findings simply extend a procession of such outcomes by other teams. It has been a given for decades that, if forest and other ecosystems become farmland, greenhouse gas levels rise. If wilderness is restored, then the carbon dioxide levels in the atmosphere will fall.

Researchers have repeatedly argued that simply planting more trees could have a dramatic impact on global heating; that a switch towards a plant-based diet could help stem biodiversity loss and reduce emissions; and that without concerted global action, precious ecosystems could collapse altogether.

They have over and over again confirmed that conservation delivers real rewards. And they have pointed out that although nations have promised to act, such promises have not always been kept. The latest study highlights the need for action to be concerted, and global.

“These results highlight the critical importance of international co-operation in meeting these goals,” Dr Strassburg said. “Different countries have different, complementary roles to play in meeting overarching global targets on biodiversity and climate.” − Climate News Network

To save civilisation, try rewilded farmland. But that salvation depends on which land goes back to forest and savannah.

LONDON, 2 November, 2020 − An international consortium of scientists has worked out − once again − how to conserve life on the planet and absorb dramatic quantities of the atmospheric carbon that is driving potentially calamitous climate change: go for rewilded farmland, fields of crops and livestock returned to prairie and forest. And they have identified the most cost-effective way to do it.

Global salvation requires the world’s nations to do simply what they have already undertaken to do: restore 15% of cultivated land to natural forest, grassland, shrubland, wetland and desert ecosystem.

If such restoration happened in the highest priority zones, then almost two-thirds of the wild things now threatened with imminent extinction could survive.

And the restored wilderness that would protect them would also start absorbing atmospheric carbon at an accelerating rate: it could sequester an estimated 229 billion tonnes of the greenhouse gas carbon dioxide (CO2). This is almost a third of all the CO2 spilled into the atmosphere by coal, oil and gas combustion in the last 200 years.

All that would be possible if the world’s nations delivered on vows made 10 years ago in Japan, to restore 15% of ecosystems worldwide. If the 196 nations that signed up went further, and restored a carefully chosen 30%, they could save more than 70% of the million or so species sliding towards extinction, and absorb 465 billion tonnes of CO2: almost half of all the extra atmospheric carbon loaded into the atmosphere by human societies since the Industrial Revolution.

Two provisos

“Pushing forward on plans to return significant sweeps of nature to a natural state is critical to preventing ongoing biodiversity and climate crises from spinning out of control,” said Bernado Strassburg, of the Pontifical Catholic University in Brazil, who led the study.

“We show that if we’re smarter about where we restore nature, we can tick the climate, biodiversity and budget boxes on the world’s urgent to-do list.”

There is a catch. To be most effective, and for the lowest costs, nations would have to work together.

Right now, scientists report in the journal Nature, each nation has undertaken to restore 15% of its wilderness. But to save the greatest number of species, and absorb the highest levels of carbon, with the lowest cost to farmland and food security, humankind would have to assess the world as a whole, and restore those ecosystems that would serve the goals most effectively.

There is a second catch: barely a month ago, a UN report confirmed that although 196 nations agreed on 20 targets to protect biodiversity − to be achieved by 2020 − a decade ago, there has been “partial progress” in just six of them. The million species then threatened with extinction are still threatened.

Potential ignored

“Many good things are happening around the world and these should be celebrated and encouraged,” said Elizabeth Maruma Mrema, executive secretary of the Convention on Biological Diversity.

“Nevertheless the rate of biodiversity loss is unprecedented in human history, and pressures are intensifying. Earth’s living systems as a whole are being compromised.”

And that threat starts with the green things on which all life depends: in September, the Royal Botanic Gardens at Kew in London published a new study on ways to identify and care for the plants and fungi that underwrite survival for what could be seven million or more species alive on the planet, and more than seven billion humans.

The study, involving 210 scientists in 42 countries, said Alexandre Antonelli, director of science at the Royal Botanic Gardens, paints a picture “of a world that has turned its back on the incredible potential of plant and fungal kingdoms to address some of the biggest challenges we face.

“We have particularly earmarked the gaps in our knowledge, the changes we are seeing, the species being named new to science and the shocking pace of biodiversity loss.”

“The rate of biodiversity loss is unprecedented in human history, and pressures are intensifying. Earth’s living systems as a whole are being compromised”

The most recent finding builds on the drive not just to fulfil the obligations undertaken 10 years ago, but to identify the very best ways to fulfil them, so as to benefit the greatest number of people.

It delivers the evidence that restoration in the most carefully chosen regions would have the most profound impact: put simply, restoration could be 13 times more cost-effective if it happened in what the Nature researchers have identified as the highest priority locations.

They used sophisticated mathematical tools and detailed geographic data to take a closer look at the 28.7 million square kilometres of natural wilderness that have been converted to farmland: 54% of these were originally forest, 25% grasslands, 14% shrublands, 4% arid lands and 2% wetland.

They then tested these areas against three considerations: their value as habitat, their capacity for carbon storage and their cost-effectiveness. And they came up with recommendations that would deliver 91% of the potential benefit for plants and animals of the wilderness and 82% of the climate mitigation benefit, and reduce costs by 27%.

And then they considered the nation-by-nation approach: were each country to restore 15% of its own forests, the biodiversity boon fell by 28%, the climate benefits by 29%, while the costs would rise by 52%.

Vital partnership

They then considered the impact on the world’s food supplies, to find that 15.78 million sq kms, or 55% of wilderness converted to farmland, could be restored without squeezing food supplies, always providing nations encouraged what they call the “sustainable intensification” of farming, along with a reduction in food waste and a move away from meat and dairy products.

The findings simply extend a procession of such outcomes by other teams. It has been a given for decades that, if forest and other ecosystems become farmland, greenhouse gas levels rise. If wilderness is restored, then the carbon dioxide levels in the atmosphere will fall.

Researchers have repeatedly argued that simply planting more trees could have a dramatic impact on global heating; that a switch towards a plant-based diet could help stem biodiversity loss and reduce emissions; and that without concerted global action, precious ecosystems could collapse altogether.

They have over and over again confirmed that conservation delivers real rewards. And they have pointed out that although nations have promised to act, such promises have not always been kept. The latest study highlights the need for action to be concerted, and global.

“These results highlight the critical importance of international co-operation in meeting these goals,” Dr Strassburg said. “Different countries have different, complementary roles to play in meeting overarching global targets on biodiversity and climate.” − Climate News Network

African desert is home to abundant forest growth

Researchers have found an unknown wealth of trees in an African desert zone supposedly too arid for green growth.

LONDON, 27 October, 2020 − With help from high resolution satellite imagery and some advanced artificial intelligence techniques, European scientists have been counting the trees in a parched African desert.

They pored over 1.3 million square kilometres of the waterless western Sahara and the arid lands of the Sahel to the south, to identify what is in effect an unknown forest. This region − a stretch of dunes and dryland larger than Angola, or Peru, or Niger − proved to be home to 1.8 billion trees and shrubs with crowns larger than three square metres.

“We were very surprised to see that quite a few trees actually grow in the Sahara Desert because up till now, most people thought that virtually none existed. We counted hundreds of millions of trees in the desert alone,” said Martin Brandt, a geographer at the University of Copenhagen in Denmark, who led the research.

He and colleagues from Germany, France, Senegal, Belgium and Nasa in the US report in the journal Nature that they used an artificial intelligence technique called “deep learning” and satellite imagery so advanced that − from space − a camera could resolve an object half a metre or more in diameter, to see if they could answer unresolved questions about all those trees beyond the world’s forests.

“Trees outside of forested areas are not usually included in climate models, and we know very little about their carbon stocks. They are  an unknown component in the global carbon cycle”

Trees matter, wherever they are. In cities, they enhance urban life and sustain property values. In forests, they conserve and recycle water, shelter millions of animals and smaller plants, and absorb atmospheric carbon. In grasslands they conserve soils, offer habitat for species and provide subsistence fuel, food and fodder for humans and animals.
But trees beyond the forests are an unknown factor when it comes to the puzzle of the global carbon budget and the great challenge of containing runaway climate change.

“Trees outside of forested areas are not usually included in climate models, and we know very little about their carbon stocks,” Dr Brandt said. “They are basically a white spot on maps and an unknown component in the global carbon cycle.”

The total identified in the target zone of the Sahara and the Sahel is almost certainly an under-estimate: the technology did not and could not pinpoint trees with a crown or shade area smaller than 3 square metres.

The study adds to the chronicle of surprises delivered by tree and forest research. In the last few years scientists have essayed a global census of woody growths wider than 5cms at breast height − that’s the botanist’s definition of a tree − and arrived at a total of more than 3 trillion.

New map possible

They have also counted the different kinds of tree: more than 60,000 species. They have already made attempts to measure the extent of tree cover in dryland and savannah regions and identified a kind of hidden forest.

They have calculated that a determined global tree planting campaign could absorb enough carbon to make a formidable difference to the challenge of global heating, and they have confirmed that conserved natural forests are, even on the simple basis of human economics, a bargain: forests are worth more to the world when they flourish than when they are cleared.

The new approach − the match of artificial intelligence with high resolution imagery − could one day help identify not just trees, but different tree species. It could, researchers hope, eventually even provide a reliable count of trees in a forest, although where canopies overlap it will always be difficult to number the trunks that support them. It offers the world’s forest scientists a new starting point for a map of all the planet’s trees.

“Doing so wouldn’t have been possible without this technology,” Dr Brandt said. “Indeed, I think it marks the beginning of a new scientific era.” − Climate News Network

Researchers have found an unknown wealth of trees in an African desert zone supposedly too arid for green growth.

LONDON, 27 October, 2020 − With help from high resolution satellite imagery and some advanced artificial intelligence techniques, European scientists have been counting the trees in a parched African desert.

They pored over 1.3 million square kilometres of the waterless western Sahara and the arid lands of the Sahel to the south, to identify what is in effect an unknown forest. This region − a stretch of dunes and dryland larger than Angola, or Peru, or Niger − proved to be home to 1.8 billion trees and shrubs with crowns larger than three square metres.

“We were very surprised to see that quite a few trees actually grow in the Sahara Desert because up till now, most people thought that virtually none existed. We counted hundreds of millions of trees in the desert alone,” said Martin Brandt, a geographer at the University of Copenhagen in Denmark, who led the research.

He and colleagues from Germany, France, Senegal, Belgium and Nasa in the US report in the journal Nature that they used an artificial intelligence technique called “deep learning” and satellite imagery so advanced that − from space − a camera could resolve an object half a metre or more in diameter, to see if they could answer unresolved questions about all those trees beyond the world’s forests.

“Trees outside of forested areas are not usually included in climate models, and we know very little about their carbon stocks. They are  an unknown component in the global carbon cycle”

Trees matter, wherever they are. In cities, they enhance urban life and sustain property values. In forests, they conserve and recycle water, shelter millions of animals and smaller plants, and absorb atmospheric carbon. In grasslands they conserve soils, offer habitat for species and provide subsistence fuel, food and fodder for humans and animals.
But trees beyond the forests are an unknown factor when it comes to the puzzle of the global carbon budget and the great challenge of containing runaway climate change.

“Trees outside of forested areas are not usually included in climate models, and we know very little about their carbon stocks,” Dr Brandt said. “They are basically a white spot on maps and an unknown component in the global carbon cycle.”

The total identified in the target zone of the Sahara and the Sahel is almost certainly an under-estimate: the technology did not and could not pinpoint trees with a crown or shade area smaller than 3 square metres.

The study adds to the chronicle of surprises delivered by tree and forest research. In the last few years scientists have essayed a global census of woody growths wider than 5cms at breast height − that’s the botanist’s definition of a tree − and arrived at a total of more than 3 trillion.

New map possible

They have also counted the different kinds of tree: more than 60,000 species. They have already made attempts to measure the extent of tree cover in dryland and savannah regions and identified a kind of hidden forest.

They have calculated that a determined global tree planting campaign could absorb enough carbon to make a formidable difference to the challenge of global heating, and they have confirmed that conserved natural forests are, even on the simple basis of human economics, a bargain: forests are worth more to the world when they flourish than when they are cleared.

The new approach − the match of artificial intelligence with high resolution imagery − could one day help identify not just trees, but different tree species. It could, researchers hope, eventually even provide a reliable count of trees in a forest, although where canopies overlap it will always be difficult to number the trunks that support them. It offers the world’s forest scientists a new starting point for a map of all the planet’s trees.

“Doing so wouldn’t have been possible without this technology,” Dr Brandt said. “Indeed, I think it marks the beginning of a new scientific era.” − Climate News Network

Western US and Southeast Asia face rising dust risk

It obscures the skies and darkens the snows. Wind-borne dust risk is increasingly ominous in a warming world.

LONDON, 26 October, 2020 − Half a planet apart, one low-lying and the other on the roof of the world, two huge regions confront an increasing dust risk − a menace to jobs, to food and to lives.

The Great Plains of North America are getting dustier every year because more soil is now being exposed to erosion. And high in the Himalayas on the continent of Asia, the peaks too are becoming dustier, in ways that threaten to increase the melting of high-altitude snows.

Both findings are in essence bad news. In the western US, higher levels of wind erosion as a consequence of changing farm practices combined with ever-greater probabilities of drought mean ever-higher probabilities of a return of the Dust Bowl that devastated the US Midwest 90 years ago.

And 700 million people in Southeast Asia, China and India depend on the slow melting of the Himalayan glaciers to irrigate their crops in the hot dry season: earlier melting threatens not just livelihoods but lives.

Taken for farming

In the 1930s, the Great Plains region was hit by drought that extended from Canada to Mexico. By then, vast tracts of prairie had been converted from wild grassland to ploughed field.

“The result was massive dust storms we associate with the Dust Bowl. These dust storms removed nutrients from the soil, making it difficult for crops to grow and more likely for wind erosion to occur,” said Andrew Lambert of the University of Utah.

He and colleagues from Colorado report in the journal Geophysical Research Letters that they measured atmospheric dust levels by studying evidence from both space and from the ground, and collected data from 1988 to 2018.

They found that atmospheric dust over the Great Plains was increasing at 5% a year. That would mean a doubling in just two decades.

“The massive dust storms we associate with the Dust Bowl removed nutrients from the soil, making it difficult for crops to grow and more likely for wind erosion to occur”

They also found that levels of dust matched the planting and harvest months of soybean in the north, and corn in the southern states. How the land was farmed could be connected directly to the haze in the air.

Dust plays a powerful role in planetary management: researchers established years ago that the rich biodiversity of the Amazon rainforest was nourished and supplemented almost annually by deposits of fertile dust blown across the Atlantic from the African Sahara. And dust falling into the ocean on the journey also helped nourish marine life far below the surface of the Atlantic.

Now it seems that wind-blown dust from two continents also settles on the biggest and highest tracts of the Himalayas, to darken the snow, change its reflectivity and absorb the sun’s warmth.

Scientists from the US Pacific Northwest National Laboratory report in Nature Climate Change that they used detailed satellite imagery of the Himalayas to measure aerosols, elevation and snow surfaces to identify dust and other pollutants.

Constant release

They found that, at up to 4500 metres altitude, black carbon or soot played an important role in influencing the melt timetable of the high snows. Above that altitude, dust was the most important factor: dust from the Thar desert in India, from Saudi Arabia and even from the African Sahara.

Although this was part of a natural cycle, humankind may be accelerating the traffic and adding to the dust risk: ever-higher planetary temperatures have begun to affect atmospheric circulation. And as humans turn natural ecosystems into farmland, they release even more dust.

“The snow in the western Himalayas is receding rapidly. We need to understand why this is happening and we need to understand the implications,” said Chandan Sarangi, then at Pacific Northwest but now at the Madras Institute of Technology in Chennai, and one of the authors.

“We’ve shown that dust can be a big contributor to the accelerated snowmelt. Hundreds of millions of people in the region rely on snow for their drinking water − we need to consider factors like dust seriously to understand what’s happening.” − Climate News Network

It obscures the skies and darkens the snows. Wind-borne dust risk is increasingly ominous in a warming world.

LONDON, 26 October, 2020 − Half a planet apart, one low-lying and the other on the roof of the world, two huge regions confront an increasing dust risk − a menace to jobs, to food and to lives.

The Great Plains of North America are getting dustier every year because more soil is now being exposed to erosion. And high in the Himalayas on the continent of Asia, the peaks too are becoming dustier, in ways that threaten to increase the melting of high-altitude snows.

Both findings are in essence bad news. In the western US, higher levels of wind erosion as a consequence of changing farm practices combined with ever-greater probabilities of drought mean ever-higher probabilities of a return of the Dust Bowl that devastated the US Midwest 90 years ago.

And 700 million people in Southeast Asia, China and India depend on the slow melting of the Himalayan glaciers to irrigate their crops in the hot dry season: earlier melting threatens not just livelihoods but lives.

Taken for farming

In the 1930s, the Great Plains region was hit by drought that extended from Canada to Mexico. By then, vast tracts of prairie had been converted from wild grassland to ploughed field.

“The result was massive dust storms we associate with the Dust Bowl. These dust storms removed nutrients from the soil, making it difficult for crops to grow and more likely for wind erosion to occur,” said Andrew Lambert of the University of Utah.

He and colleagues from Colorado report in the journal Geophysical Research Letters that they measured atmospheric dust levels by studying evidence from both space and from the ground, and collected data from 1988 to 2018.

They found that atmospheric dust over the Great Plains was increasing at 5% a year. That would mean a doubling in just two decades.

“The massive dust storms we associate with the Dust Bowl removed nutrients from the soil, making it difficult for crops to grow and more likely for wind erosion to occur”

They also found that levels of dust matched the planting and harvest months of soybean in the north, and corn in the southern states. How the land was farmed could be connected directly to the haze in the air.

Dust plays a powerful role in planetary management: researchers established years ago that the rich biodiversity of the Amazon rainforest was nourished and supplemented almost annually by deposits of fertile dust blown across the Atlantic from the African Sahara. And dust falling into the ocean on the journey also helped nourish marine life far below the surface of the Atlantic.

Now it seems that wind-blown dust from two continents also settles on the biggest and highest tracts of the Himalayas, to darken the snow, change its reflectivity and absorb the sun’s warmth.

Scientists from the US Pacific Northwest National Laboratory report in Nature Climate Change that they used detailed satellite imagery of the Himalayas to measure aerosols, elevation and snow surfaces to identify dust and other pollutants.

Constant release

They found that, at up to 4500 metres altitude, black carbon or soot played an important role in influencing the melt timetable of the high snows. Above that altitude, dust was the most important factor: dust from the Thar desert in India, from Saudi Arabia and even from the African Sahara.

Although this was part of a natural cycle, humankind may be accelerating the traffic and adding to the dust risk: ever-higher planetary temperatures have begun to affect atmospheric circulation. And as humans turn natural ecosystems into farmland, they release even more dust.

“The snow in the western Himalayas is receding rapidly. We need to understand why this is happening and we need to understand the implications,” said Chandan Sarangi, then at Pacific Northwest but now at the Madras Institute of Technology in Chennai, and one of the authors.

“We’ve shown that dust can be a big contributor to the accelerated snowmelt. Hundreds of millions of people in the region rely on snow for their drinking water − we need to consider factors like dust seriously to understand what’s happening.” − Climate News Network

Geology’s human footprint is enough to spur rage

Once again science has presented evidence that a new geological epoch is here. This human footprint is all our own work.

LONDON, 21 October, 2020 − The human footprint has left its mark on Earth, in every sense. The United States alone is scarred by 500,000 abandoned mines and quarries.

Right now, worldwide, there are more than 500,000 active quarries and pits, employing 4 million people, excavating the sand and gravel needed for new roads, new homes and new megacities.

Humans have not simply pitted the face of the Earth, they have paved it. In 1904, beyond the cities, the US had just 225 km of sealed highway. Now it has 4.3m km of asphalt or concrete roadway, consuming more than 20 billion tonnes of sand and gravel.

By comparison, the Great Wall of China, the biggest and most enduring construction in early human history, contains just 0.4bn tonnes of stone.

Humans have changed the face of the waters. In 1950, trawlers, long-liners and purse seiners fished just 1% of the high seas beyond territorial waters. No fish species of any kind was considered over-exploited or depleted.

Extinction threat widens

Less than one human lifetime on, fishing fleets roam 63% of the high seas and 87% of fish species are exploited, over-exploited or in a state of collapse. Meanwhile somewhere between 5m and almost 13 million tons of discarded plastics flow each year into the sea.

Humans and human livestock now far outweigh all other mammalian life. At least 96% of the mass of all mammals is represented by humans and their domesticated animals. Domestic poultry makes up 70% of the mass of all living birds. The natural world is now endangered, with a million species at risk of extinction.

And humans have left an almost indelible radiant signature over the entire global surface: between 1950 and 1980, nations detonated more than 500 thermonuclear weapons to smear the air and surface of the planet with radioactive materials: one of these, plutonium-239, will be detectable for the next 100,000 years.

The catalogue of planetary devastation that is the human footprint is assembled in a new study by US and European scientists in the journal Nature Communications: Earth and Environment. It is part of a fresh attempt to settle a seemingly academic question of geological bureaucracy, the naming of ages.

“We humans collectively got ourselves into this mess, we need to work together to reverse these environmental trends and dig ourselves out of it”

The 11,000-year interval since the end of the last Ice Age and the dawn of agriculture, metal smelting, and the first cities, cultures and empires is still formally identified as the Holocene. The latest study of the human legacy is just another salvo in the campaign to announce and confirm the launch of an entirely new epoch, to be called the Anthropocene.

In fact, environmental campaigners, biologists and geophysicists have for years been informally calling the last six or seven decades the Anthropocene. But the authority with the last word on internationally-agreed geological labels − the International Commission on Stratigraphy − has yet to confirm the launch of the new geological epoch.

To help confirm the case for change, researchers have once again assembled the evidence and identified at least 16 ways in which humans have dramatically altered the planet since 1950, and the beginning of what is sometimes called The Great Acceleration.

For instance, humans have doubled the quantity of fixed nitrogen in the biosphere, created an alarming hole in the stratospheric ozone layer, released enough gases to raise the planetary temperature and precipitate global climate change, fashioned or forged perhaps 180,000 kinds of mineral (by comparison, only about 5,300 occur naturally) and − with dams, drains, wells, irrigation, and hydraulic engineering − effectively replumbed the world’s river systems.

Ineradicable scar

By forging metals and building structures, humans have become the greatest earth-moving force on the planet, and left a mark that will endure for aeons.

Altogether, humans have altered the world’s rivers, lakes, coastlines, vegetation, soils, chemistry and climate. The study makes grim reading.

“This is the first time that humans have documented humanity’s geological footprint on such a comprehensive scale in a single publication,” said Jaia Syvitski, of the University of Colorado, Boulder, who led the research team that assembled the evidence.

“We humans collectively got ourselves into this mess, we need to work together to reverse these environmental trends and dig ourselves out of it.

“Society shouldn’t feel complacent. Few people who read the manuscript should come away without emotions bubbling up, like rage, grief and even fear.” − Climate News Network

Once again science has presented evidence that a new geological epoch is here. This human footprint is all our own work.

LONDON, 21 October, 2020 − The human footprint has left its mark on Earth, in every sense. The United States alone is scarred by 500,000 abandoned mines and quarries.

Right now, worldwide, there are more than 500,000 active quarries and pits, employing 4 million people, excavating the sand and gravel needed for new roads, new homes and new megacities.

Humans have not simply pitted the face of the Earth, they have paved it. In 1904, beyond the cities, the US had just 225 km of sealed highway. Now it has 4.3m km of asphalt or concrete roadway, consuming more than 20 billion tonnes of sand and gravel.

By comparison, the Great Wall of China, the biggest and most enduring construction in early human history, contains just 0.4bn tonnes of stone.

Humans have changed the face of the waters. In 1950, trawlers, long-liners and purse seiners fished just 1% of the high seas beyond territorial waters. No fish species of any kind was considered over-exploited or depleted.

Extinction threat widens

Less than one human lifetime on, fishing fleets roam 63% of the high seas and 87% of fish species are exploited, over-exploited or in a state of collapse. Meanwhile somewhere between 5m and almost 13 million tons of discarded plastics flow each year into the sea.

Humans and human livestock now far outweigh all other mammalian life. At least 96% of the mass of all mammals is represented by humans and their domesticated animals. Domestic poultry makes up 70% of the mass of all living birds. The natural world is now endangered, with a million species at risk of extinction.

And humans have left an almost indelible radiant signature over the entire global surface: between 1950 and 1980, nations detonated more than 500 thermonuclear weapons to smear the air and surface of the planet with radioactive materials: one of these, plutonium-239, will be detectable for the next 100,000 years.

The catalogue of planetary devastation that is the human footprint is assembled in a new study by US and European scientists in the journal Nature Communications: Earth and Environment. It is part of a fresh attempt to settle a seemingly academic question of geological bureaucracy, the naming of ages.

“We humans collectively got ourselves into this mess, we need to work together to reverse these environmental trends and dig ourselves out of it”

The 11,000-year interval since the end of the last Ice Age and the dawn of agriculture, metal smelting, and the first cities, cultures and empires is still formally identified as the Holocene. The latest study of the human legacy is just another salvo in the campaign to announce and confirm the launch of an entirely new epoch, to be called the Anthropocene.

In fact, environmental campaigners, biologists and geophysicists have for years been informally calling the last six or seven decades the Anthropocene. But the authority with the last word on internationally-agreed geological labels − the International Commission on Stratigraphy − has yet to confirm the launch of the new geological epoch.

To help confirm the case for change, researchers have once again assembled the evidence and identified at least 16 ways in which humans have dramatically altered the planet since 1950, and the beginning of what is sometimes called The Great Acceleration.

For instance, humans have doubled the quantity of fixed nitrogen in the biosphere, created an alarming hole in the stratospheric ozone layer, released enough gases to raise the planetary temperature and precipitate global climate change, fashioned or forged perhaps 180,000 kinds of mineral (by comparison, only about 5,300 occur naturally) and − with dams, drains, wells, irrigation, and hydraulic engineering − effectively replumbed the world’s river systems.

Ineradicable scar

By forging metals and building structures, humans have become the greatest earth-moving force on the planet, and left a mark that will endure for aeons.

Altogether, humans have altered the world’s rivers, lakes, coastlines, vegetation, soils, chemistry and climate. The study makes grim reading.

“This is the first time that humans have documented humanity’s geological footprint on such a comprehensive scale in a single publication,” said Jaia Syvitski, of the University of Colorado, Boulder, who led the research team that assembled the evidence.

“We humans collectively got ourselves into this mess, we need to work together to reverse these environmental trends and dig ourselves out of it.

“Society shouldn’t feel complacent. Few people who read the manuscript should come away without emotions bubbling up, like rage, grief and even fear.” − Climate News Network

Laughing gas rise leaves climate science anxious

Atmospheric levels of laughing gas are on the increase, thanks to agriculture. This is no joke for climate change.

LONDON, 14 October, 2020 − If humans are to meet the global heating limits set by international agreement in 2015, they will have to think very hard about the effect of the supper table menu on laughing gas, more formally known as nitrous oxide.

That is because food production depends heavily on nitrogen fertilisers. But greenhouse gas emissions driven by agriculture are increasing atmospheric levels of nitrous oxide (N2O).

This is a greenhouse gas − popularly known as “laughing gas” − that is 300 times more potent than carbon dioxide, and it tends to stay in the atmosphere, driving up the thermometer, for at least 100 years. And in the 200 years since the start of the Industrial Revolution, atmospheric levels of nitrous oxide have risen by 20%, and are still rising.

Nitrous oxide is one of the six greenhouse gases identified in the Kyoto Protocol, the pioneering global climate agreement, as a danger whose emissions should be reduced by all its signatories.

The ratio of N2O to other gases is tiny, a thousand times lower than carbon dioxide, for instance, but an increase can still make a significant difference. In 1750 the ratio stood at 270 parts per billion. In 2018 it had reached 331 ppb, with the fastest growth all in the last 50 years, thanks to humankind’s demand for food.

“There is a conflict between the way we are feeding people and stabilising the climate”

And this, say 57 scientists from 14 nations in a report in the journal Nature, now threatens to eliminate any hope of containing global heating to “well below” 2°C by the year 2100. This is the target set in the Paris Agreement in 2015 by 195 nations.

Right now, the world has already warmed by 1°C in the last century and on all the evidence so far it is heading by the end of the century to be at least 3°C hotter than the average for most of the last 10,000 years of human history.

“The dominant driver of the increase in atmospheric nitrous oxide comes from agriculture, and the growing demand for food and feed for animals will further increase global nitrous oxide emissions,” said Hanqin Tian, of Auburn University’s School of Forestry and Wildlife Sciences in Alabama in the US. “There is a conflict between the way we are feeding people and stabilising the climate.”

He and his colleagues call their research an inventory of the traffic in nitrous oxide from human and from natural sources. The most significant human source is the fertiliser added to croplands.

They found that the highest growth in nitrous oxide emissions came from emerging economies in East Asia, South Asia, Africa and South America, from synthetic fertilisers and from livestock manure. In the course of the next few decades global population will soar, and so will the demand for food.

Total rethink

Researchers have consistently argued for a new approach to agriculture,  with ever-greater emphasis on plant-based diets, as a way to help contain climate change on a scale that is likely to actually threaten global food security.

“Europe is the only region in the world that has successfully reduced nitrous oxide emissions over the past two decades,” said Robert Jackson,  of Stanford University in the US, who chairs the Global Carbon Project.

“Industrial and agricultural policies to reduce greenhouse gases and air pollution and to optimise fertiliser use efficiencies have proven to be effective. Still, further efforts are required, in Europe as well as globally.”

And another author, Josep Canadell of Australia’s Commonwealth Scientific and Industrial Research Organisation, said: “This new analysis calls for a full rethink in the ways we use and abuse nitrogen fertilisers globally and urges us to adopt more sustainable practices in the way we produce food,  including the reduction of food waste.” − Climate News Network

Atmospheric levels of laughing gas are on the increase, thanks to agriculture. This is no joke for climate change.

LONDON, 14 October, 2020 − If humans are to meet the global heating limits set by international agreement in 2015, they will have to think very hard about the effect of the supper table menu on laughing gas, more formally known as nitrous oxide.

That is because food production depends heavily on nitrogen fertilisers. But greenhouse gas emissions driven by agriculture are increasing atmospheric levels of nitrous oxide (N2O).

This is a greenhouse gas − popularly known as “laughing gas” − that is 300 times more potent than carbon dioxide, and it tends to stay in the atmosphere, driving up the thermometer, for at least 100 years. And in the 200 years since the start of the Industrial Revolution, atmospheric levels of nitrous oxide have risen by 20%, and are still rising.

Nitrous oxide is one of the six greenhouse gases identified in the Kyoto Protocol, the pioneering global climate agreement, as a danger whose emissions should be reduced by all its signatories.

The ratio of N2O to other gases is tiny, a thousand times lower than carbon dioxide, for instance, but an increase can still make a significant difference. In 1750 the ratio stood at 270 parts per billion. In 2018 it had reached 331 ppb, with the fastest growth all in the last 50 years, thanks to humankind’s demand for food.

“There is a conflict between the way we are feeding people and stabilising the climate”

And this, say 57 scientists from 14 nations in a report in the journal Nature, now threatens to eliminate any hope of containing global heating to “well below” 2°C by the year 2100. This is the target set in the Paris Agreement in 2015 by 195 nations.

Right now, the world has already warmed by 1°C in the last century and on all the evidence so far it is heading by the end of the century to be at least 3°C hotter than the average for most of the last 10,000 years of human history.

“The dominant driver of the increase in atmospheric nitrous oxide comes from agriculture, and the growing demand for food and feed for animals will further increase global nitrous oxide emissions,” said Hanqin Tian, of Auburn University’s School of Forestry and Wildlife Sciences in Alabama in the US. “There is a conflict between the way we are feeding people and stabilising the climate.”

He and his colleagues call their research an inventory of the traffic in nitrous oxide from human and from natural sources. The most significant human source is the fertiliser added to croplands.

They found that the highest growth in nitrous oxide emissions came from emerging economies in East Asia, South Asia, Africa and South America, from synthetic fertilisers and from livestock manure. In the course of the next few decades global population will soar, and so will the demand for food.

Total rethink

Researchers have consistently argued for a new approach to agriculture,  with ever-greater emphasis on plant-based diets, as a way to help contain climate change on a scale that is likely to actually threaten global food security.

“Europe is the only region in the world that has successfully reduced nitrous oxide emissions over the past two decades,” said Robert Jackson,  of Stanford University in the US, who chairs the Global Carbon Project.

“Industrial and agricultural policies to reduce greenhouse gases and air pollution and to optimise fertiliser use efficiencies have proven to be effective. Still, further efforts are required, in Europe as well as globally.”

And another author, Josep Canadell of Australia’s Commonwealth Scientific and Industrial Research Organisation, said: “This new analysis calls for a full rethink in the ways we use and abuse nitrogen fertilisers globally and urges us to adopt more sustainable practices in the way we produce food,  including the reduction of food waste.” − Climate News Network

River deltas become even riskier as climate warms

River deltas are among the world’s richest habitats. They are also, increasingly, home to the most vulnerable people.

LONDON, 8 October, 2020 − Already, more than 30 million people worldwide are in danger of catastrophic floods − and now they face further danger from the river deltas which are their homes.

Ocean storm surges which are one threat could wash away their homes, their livelihoods, and even their lives. Another, rising tide levels, could turn their gardens to salt and sap the foundations of their lives. With many more, tropical cyclones could sweep in and literally rain their houses into the sea

What all these vulnerable people − in New Orleans, in Bangkok, in Shanghai, in the mouths of the Ganges-Brahmaputra, in any of more than 2,000 settlements − have in common is that they live on a river delta: that vital, ever-shifting zone where a great river spills its silt into the ocean.

And climate change driven by ever-rising ratios of greenhouse gases in the atmosphere − a consequence of ever-greater reliance on fossil fuels − can only make such hazards ever more dangerous. But the first challenge is: who, exactly, is most at risk? And where?

“To date, no-one has successfully quantified the global population in river deltas and assessed the cumulative impacts from climate change,” said Douglas Edmonds, of the University of Indiana in the US.

Costly endowment

“Since river deltas have long been recognised as hotspots of population growth, and with increasing impacts from climate change, we realised we needed to properly quantify what the cumulative risks are in river deltas.”

Dr Edmonds and his colleagues report in Nature Communications that they assembled a global database of 2,174 delta locations, to identity the populations settled on and around them in 2017, and the topography most at risk.

River deltas add up to perhaps 0.5% of the planet’s land surface, but they are home to 4.5% of the world’s population. Humans have settled on river deltas for at least 7,000 years: the rivers deliver nutrient-rich silts for new farmland, and the river estuaries have provided a focus for regional and international transport, to become some of the world’s greatest cities.

But such riches come at a cost: as the rivers have been contained and engineered, the land cover has changed and the land surface subsided. So as sea levels rise with climate change, deltaic areas could become 50% more vulnerable to coastal flood.

“No-one has successfully quantified the global population in river deltas and assessed the cumulative impacts from climate change”

Precisely because river deltas form at or even below sea level, they are highly prone to storm surges driven by tropical cyclones. And by 2100, these could become from 2% to 11% more intense.

The researchers found that in 2017, around 339m people had made their homes on 710,000 square kilometres of habitable land around river deltas: in this century alone, the population on deltas had grown by 34%.

Of these, 31m lived on floodplains vulnerable to the kind of storm surges that happen once a century. And of this 31m, 92% lived in developing or least-developed economies, often breathing polluted air, with poor housing and limited access to public services such as drainage. So, as usual, the poorest were also the most at risk from climate change.

In fact, as scientists have been warning for a decade or more, coastal flooding is a hazard inevitably on the increase, and an increasingly costly one, worldwide.

Even in the US, floods will become a serial nuisance in many cities and an estimated 13m Americans could eventually become climate refugees.

Very cautious estimates

Climate change is likely to deliver a hotter, wetter world with more soil erosion that could trigger catastrophic delta flooding. Hurricanes and typhoons driven by rising sea temperatures are likely to exact an ever-greater toll on human life and wealth.

The Indiana scientists warn that their estimates of those most at risk and the costs they face are likely to be highly conservative. They did not, for instance, consider the special case of what they call “compound interaction.”

This is sociological shorthand for what could happen when climate-related disaster overtakes those who are poorest, crowded into the least protected and unhealthiest zones of the cities. Altogether, 105m people have settled on the Ganges-Brahmaputra delta, half of them on low-lying farmland. The second most crowded is the Nile delta, with 45m people.

“To effectively prepare for more intense future coastal flooding,” Dr Edmonds said, “we need to reframe it as a problem that disproportionately impacts people on river deltas in developing and least developed economies.” − Climate News Network

River deltas are among the world’s richest habitats. They are also, increasingly, home to the most vulnerable people.

LONDON, 8 October, 2020 − Already, more than 30 million people worldwide are in danger of catastrophic floods − and now they face further danger from the river deltas which are their homes.

Ocean storm surges which are one threat could wash away their homes, their livelihoods, and even their lives. Another, rising tide levels, could turn their gardens to salt and sap the foundations of their lives. With many more, tropical cyclones could sweep in and literally rain their houses into the sea

What all these vulnerable people − in New Orleans, in Bangkok, in Shanghai, in the mouths of the Ganges-Brahmaputra, in any of more than 2,000 settlements − have in common is that they live on a river delta: that vital, ever-shifting zone where a great river spills its silt into the ocean.

And climate change driven by ever-rising ratios of greenhouse gases in the atmosphere − a consequence of ever-greater reliance on fossil fuels − can only make such hazards ever more dangerous. But the first challenge is: who, exactly, is most at risk? And where?

“To date, no-one has successfully quantified the global population in river deltas and assessed the cumulative impacts from climate change,” said Douglas Edmonds, of the University of Indiana in the US.

Costly endowment

“Since river deltas have long been recognised as hotspots of population growth, and with increasing impacts from climate change, we realised we needed to properly quantify what the cumulative risks are in river deltas.”

Dr Edmonds and his colleagues report in Nature Communications that they assembled a global database of 2,174 delta locations, to identity the populations settled on and around them in 2017, and the topography most at risk.

River deltas add up to perhaps 0.5% of the planet’s land surface, but they are home to 4.5% of the world’s population. Humans have settled on river deltas for at least 7,000 years: the rivers deliver nutrient-rich silts for new farmland, and the river estuaries have provided a focus for regional and international transport, to become some of the world’s greatest cities.

But such riches come at a cost: as the rivers have been contained and engineered, the land cover has changed and the land surface subsided. So as sea levels rise with climate change, deltaic areas could become 50% more vulnerable to coastal flood.

“No-one has successfully quantified the global population in river deltas and assessed the cumulative impacts from climate change”

Precisely because river deltas form at or even below sea level, they are highly prone to storm surges driven by tropical cyclones. And by 2100, these could become from 2% to 11% more intense.

The researchers found that in 2017, around 339m people had made their homes on 710,000 square kilometres of habitable land around river deltas: in this century alone, the population on deltas had grown by 34%.

Of these, 31m lived on floodplains vulnerable to the kind of storm surges that happen once a century. And of this 31m, 92% lived in developing or least-developed economies, often breathing polluted air, with poor housing and limited access to public services such as drainage. So, as usual, the poorest were also the most at risk from climate change.

In fact, as scientists have been warning for a decade or more, coastal flooding is a hazard inevitably on the increase, and an increasingly costly one, worldwide.

Even in the US, floods will become a serial nuisance in many cities and an estimated 13m Americans could eventually become climate refugees.

Very cautious estimates

Climate change is likely to deliver a hotter, wetter world with more soil erosion that could trigger catastrophic delta flooding. Hurricanes and typhoons driven by rising sea temperatures are likely to exact an ever-greater toll on human life and wealth.

The Indiana scientists warn that their estimates of those most at risk and the costs they face are likely to be highly conservative. They did not, for instance, consider the special case of what they call “compound interaction.”

This is sociological shorthand for what could happen when climate-related disaster overtakes those who are poorest, crowded into the least protected and unhealthiest zones of the cities. Altogether, 105m people have settled on the Ganges-Brahmaputra delta, half of them on low-lying farmland. The second most crowded is the Nile delta, with 45m people.

“To effectively prepare for more intense future coastal flooding,” Dr Edmonds said, “we need to reframe it as a problem that disproportionately impacts people on river deltas in developing and least developed economies.” − Climate News Network

Fire and drought could trigger Amazon collapse

Amazon collapse could soon mean the end of one of Earth’s richest habitats, leaving the rainforest destroyed by humans.

LONDON, 30 September, 2020 – Within one human lifetime, Amazon collapse could have turned the rainforest into open savannah.

The combined devastation of human-induced global warming, rapidly increasing degradation or destruction of the forest, natural climate cycles and catastrophic wildfires could be enough to bring the world’s biggest, richest and most vital forest to a tipping point: towards a new kind of habitat.

“The risk that our generation will preside over the irreversible collapse of Amazonian and Andean biodiversity is huge, literally existential,” warns Mark Bush of the Florida Institute of Technology, in the latest Annals of the Missouri Botanical Garden.

Professor Bush bases his argument on the evidence of history: painstaking study of fossil pollen and charcoal in the sediments of Andean lakes confirms that the profligate biodiversity of the Amazon has been disturbed many times in the past, as global climate has varied with the retreat and advance of the glaciers.

It has, however, never reached a tipping point towards collapse, if only because it has never before had to face the hazard of fire on the present scale.

There is another factor: ever-greater human intrusion into, degradation of, or conversion of forest into plantation or ranch land heightens the hazard of a dramatic shift from moist tropical canopy to open and wooded grasslands.

And then, the argument goes, there are the ever-higher temperatures driven by ever-greater greenhouse gas emissions from human investment in fossil fuel energy, and ever more extensive destruction of the natural habitats that in the past have absorbed atmospheric carbon. And with higher temperatures, there arrives the risk of ever more catastrophic drought.

“From a human perspective, the forest has just become much easier to clear”

A river of moist air flows from east to west across Amazonia to the Andes. What falls as rain is absorbed by the vegetation or evaporated by the sun and transpired through the treetops to provide yet more water vapour to fall again, and again. Effectively, the western Amazon rainforest and the Andean forests are almost entirely dependent on recycled moisture.

This recycling falls away as the canopy goes: evapo-transpiration from the savannah is less than two-thirds of that from the forest. Cropland returns only a tenth of its moisture to the skies. So that makes the forest inland from the Atlantic increasingly vulnerable to change.

The region has recovered from climate turbulence many times before. But the regional temperature has warmed by 1°C to 1.5C in the past century, and researchers have repeatedly warned that a combination of severe deforestation and a warming of 3°C or more could turn the forest into savannah.

In the last 15 years, Amazonia has experienced three “droughts of the century”, in 2005, 2010 and 2015-16. The effects of these, Professor Bush warns, “may be protracted, and possibly irreversible.”

His warning may sound apocalyptic. In fact, he is only saying out loud what has been implicit in research and reporting from the region for years.

Drought and fire present a kind of double jeopardy to any forest. Drought and fire could, researchers have repeatedly warned, turn the Amazon from an absorber of carbon to a source of greenhouse gases, to make global heating even worse.

Drought has already damaged large tracts of forest and although legislation in theory protects the wilderness the recent damage has been on a scale big enough to alarm faraway nations.

Tipping point possible

High temperatures change ecosystems: some plants simply cannot cope. The region is one of the richest and most important on the planet. Loss of the Amazon would represent a climate tipping point, and researchers have been warning for years that such possible slides toward irreversible change are imminent.

In a drought, more trees die. Standing deadwood becomes treefall, and so much tinder waiting to catch fire. As the canopy opens up, local temperatures soar by as much as 10°C, and in a deforested region humidity drops by 30%.

For humans looking for roads to clear, minerals to mine, ground to plant or cattle to run, opportunity beckons. “From a human perspective, the forest has just become much easier to clear,” says Professor Bush.

So the effects of the droughts accumulate, and encourage the invasion of yet more humans with chainsaws and fire. The western Amazon is already a potential tipping point: in 2016, Bolivia’s second largest lake – an important commercial fishery – dried up between January and November.

Given the rates of deforestation and the temperatures to come, the Amazon tipping point – the loss of a massive rainforest – could occur by mid-century. The slide to a new kind of ecosystem would be irreversible.

“The immense biodiversity of the rainforest is at risk from fire,” said Professor Bush. “Warming alone could induce the tipping point by mid-century, but if the present policies that turn a blind eye to forest destruction aren’t stopped, we could reach the tipping point much sooner.”

He warned: “Beyond the loss of wildlife, the cascading effects of losing Amazonian rainforest would alter rainfall across the hemisphere. This is not a remote problem, but one of global importance and critical significance to food security that should concern us all.” – Climate News Network

Amazon collapse could soon mean the end of one of Earth’s richest habitats, leaving the rainforest destroyed by humans.

LONDON, 30 September, 2020 – Within one human lifetime, Amazon collapse could have turned the rainforest into open savannah.

The combined devastation of human-induced global warming, rapidly increasing degradation or destruction of the forest, natural climate cycles and catastrophic wildfires could be enough to bring the world’s biggest, richest and most vital forest to a tipping point: towards a new kind of habitat.

“The risk that our generation will preside over the irreversible collapse of Amazonian and Andean biodiversity is huge, literally existential,” warns Mark Bush of the Florida Institute of Technology, in the latest Annals of the Missouri Botanical Garden.

Professor Bush bases his argument on the evidence of history: painstaking study of fossil pollen and charcoal in the sediments of Andean lakes confirms that the profligate biodiversity of the Amazon has been disturbed many times in the past, as global climate has varied with the retreat and advance of the glaciers.

It has, however, never reached a tipping point towards collapse, if only because it has never before had to face the hazard of fire on the present scale.

There is another factor: ever-greater human intrusion into, degradation of, or conversion of forest into plantation or ranch land heightens the hazard of a dramatic shift from moist tropical canopy to open and wooded grasslands.

And then, the argument goes, there are the ever-higher temperatures driven by ever-greater greenhouse gas emissions from human investment in fossil fuel energy, and ever more extensive destruction of the natural habitats that in the past have absorbed atmospheric carbon. And with higher temperatures, there arrives the risk of ever more catastrophic drought.

“From a human perspective, the forest has just become much easier to clear”

A river of moist air flows from east to west across Amazonia to the Andes. What falls as rain is absorbed by the vegetation or evaporated by the sun and transpired through the treetops to provide yet more water vapour to fall again, and again. Effectively, the western Amazon rainforest and the Andean forests are almost entirely dependent on recycled moisture.

This recycling falls away as the canopy goes: evapo-transpiration from the savannah is less than two-thirds of that from the forest. Cropland returns only a tenth of its moisture to the skies. So that makes the forest inland from the Atlantic increasingly vulnerable to change.

The region has recovered from climate turbulence many times before. But the regional temperature has warmed by 1°C to 1.5C in the past century, and researchers have repeatedly warned that a combination of severe deforestation and a warming of 3°C or more could turn the forest into savannah.

In the last 15 years, Amazonia has experienced three “droughts of the century”, in 2005, 2010 and 2015-16. The effects of these, Professor Bush warns, “may be protracted, and possibly irreversible.”

His warning may sound apocalyptic. In fact, he is only saying out loud what has been implicit in research and reporting from the region for years.

Drought and fire present a kind of double jeopardy to any forest. Drought and fire could, researchers have repeatedly warned, turn the Amazon from an absorber of carbon to a source of greenhouse gases, to make global heating even worse.

Drought has already damaged large tracts of forest and although legislation in theory protects the wilderness the recent damage has been on a scale big enough to alarm faraway nations.

Tipping point possible

High temperatures change ecosystems: some plants simply cannot cope. The region is one of the richest and most important on the planet. Loss of the Amazon would represent a climate tipping point, and researchers have been warning for years that such possible slides toward irreversible change are imminent.

In a drought, more trees die. Standing deadwood becomes treefall, and so much tinder waiting to catch fire. As the canopy opens up, local temperatures soar by as much as 10°C, and in a deforested region humidity drops by 30%.

For humans looking for roads to clear, minerals to mine, ground to plant or cattle to run, opportunity beckons. “From a human perspective, the forest has just become much easier to clear,” says Professor Bush.

So the effects of the droughts accumulate, and encourage the invasion of yet more humans with chainsaws and fire. The western Amazon is already a potential tipping point: in 2016, Bolivia’s second largest lake – an important commercial fishery – dried up between January and November.

Given the rates of deforestation and the temperatures to come, the Amazon tipping point – the loss of a massive rainforest – could occur by mid-century. The slide to a new kind of ecosystem would be irreversible.

“The immense biodiversity of the rainforest is at risk from fire,” said Professor Bush. “Warming alone could induce the tipping point by mid-century, but if the present policies that turn a blind eye to forest destruction aren’t stopped, we could reach the tipping point much sooner.”

He warned: “Beyond the loss of wildlife, the cascading effects of losing Amazonian rainforest would alter rainfall across the hemisphere. This is not a remote problem, but one of global importance and critical significance to food security that should concern us all.” – Climate News Network

Lentils can feed the world – and save wildlife too

Wildlife could flourish if humans opted for a better diet. Think of humble, healthy lentils as the green choice.

LONDON, 24 September, 2020 – US scientists have worked out how to feed nine billion people and save wildlife from extinction, both at the same time – thanks to healthy lentils.

The answer is starkly simple: if humans got their protein from lentils, beans and nuts rather than beef, pork and chicken, they could return colossal tracts of grazing land back to the wilderness.

Nearly 40% of the planet’s land surface is now committed to agriculture. And almost 83% of this proportion is used to graze animals, or grow food for animals.

If it was returned to natural habitat, then humankind might be able to prevent the extinction of perhaps a million species now under imminent threat.

The same transition would dramatically reduce greenhouse gas emissions, help contain climate change, and perhaps even reduce the risks of new pandemics.

“We know that intact, functioning ecosystems and appropriate wildlife habitat ranges help reduce the risk of pandemics. There is potential for giving large areas of land back to wildlife”

And best of all, the burden of action could sensibly fall on the better-off nations rather than the poorest.

“The greatest potential for forest regrowth, and the climate benefits it entails, exists in high and upper-middle income countries, places where scaling back on land-hungry meat and dairy would have relatively minor impacts on food security,” said Matthew Hayek of New York University.

He and colleagues report in the journal Nature Sustainability that vegetation regrowth on once-grazed land could gulp down between nine and 16 years of human carbon dioxide emissions from fossil fuel combustion, and buy time for a worldwide switch to renewable energy.

“We can think of shifting our eating habits towards land-friendly diets as a supplement to shifting energy rather than a substitute,” he argued.  “Restoring native forests could buy some much-needed time for countries to transition their energy grids to renewable, fossil-free infrastructure.”

The warning is only the latest in a long line of studies which conclude that if humans ate less meat, the world would be a safer, healthier and better place.

Russia-sized area

The switch is unlikely to happen soon, or completely – in some places, animals are the principal food source – or very effectively. It isn’t clear that in a rapidly warming world, forests would recolonise all farmed land, or that those forests would efficiently absorb the hoped-for atmospheric carbon.

But Dr Hayek and his colleagues mapped only an area over which seeds could disperse naturally, and deliver dense and diverse forest. They identified an area that added up to seven million square kilometres, in places moist enough to thrive naturally. This is an area the size of Russia.

The simple act of abandoning selected ranchland or pasture could work wonders for water quality, wildlife habitat and biodiversity. And it would work for human health as well.

“We know that intact, functioning ecosystems and appropriate wildlife habitat ranges help reduce the risk of pandemics,” said his co-author Helen Harwatt of Harvard Law School.

“Our research shows that there is potential for giving large areas of land back to wildlife. Restoring native ecosystems not only helps the climate; when coupled with reduced livestock populations, restoration reduced disease transmission from wildlife to pigs, chickens and cows, and ultimately to humans.” – Climate News Network

Wildlife could flourish if humans opted for a better diet. Think of humble, healthy lentils as the green choice.

LONDON, 24 September, 2020 – US scientists have worked out how to feed nine billion people and save wildlife from extinction, both at the same time – thanks to healthy lentils.

The answer is starkly simple: if humans got their protein from lentils, beans and nuts rather than beef, pork and chicken, they could return colossal tracts of grazing land back to the wilderness.

Nearly 40% of the planet’s land surface is now committed to agriculture. And almost 83% of this proportion is used to graze animals, or grow food for animals.

If it was returned to natural habitat, then humankind might be able to prevent the extinction of perhaps a million species now under imminent threat.

The same transition would dramatically reduce greenhouse gas emissions, help contain climate change, and perhaps even reduce the risks of new pandemics.

“We know that intact, functioning ecosystems and appropriate wildlife habitat ranges help reduce the risk of pandemics. There is potential for giving large areas of land back to wildlife”

And best of all, the burden of action could sensibly fall on the better-off nations rather than the poorest.

“The greatest potential for forest regrowth, and the climate benefits it entails, exists in high and upper-middle income countries, places where scaling back on land-hungry meat and dairy would have relatively minor impacts on food security,” said Matthew Hayek of New York University.

He and colleagues report in the journal Nature Sustainability that vegetation regrowth on once-grazed land could gulp down between nine and 16 years of human carbon dioxide emissions from fossil fuel combustion, and buy time for a worldwide switch to renewable energy.

“We can think of shifting our eating habits towards land-friendly diets as a supplement to shifting energy rather than a substitute,” he argued.  “Restoring native forests could buy some much-needed time for countries to transition their energy grids to renewable, fossil-free infrastructure.”

The warning is only the latest in a long line of studies which conclude that if humans ate less meat, the world would be a safer, healthier and better place.

Russia-sized area

The switch is unlikely to happen soon, or completely – in some places, animals are the principal food source – or very effectively. It isn’t clear that in a rapidly warming world, forests would recolonise all farmed land, or that those forests would efficiently absorb the hoped-for atmospheric carbon.

But Dr Hayek and his colleagues mapped only an area over which seeds could disperse naturally, and deliver dense and diverse forest. They identified an area that added up to seven million square kilometres, in places moist enough to thrive naturally. This is an area the size of Russia.

The simple act of abandoning selected ranchland or pasture could work wonders for water quality, wildlife habitat and biodiversity. And it would work for human health as well.

“We know that intact, functioning ecosystems and appropriate wildlife habitat ranges help reduce the risk of pandemics,” said his co-author Helen Harwatt of Harvard Law School.

“Our research shows that there is potential for giving large areas of land back to wildlife. Restoring native ecosystems not only helps the climate; when coupled with reduced livestock populations, restoration reduced disease transmission from wildlife to pigs, chickens and cows, and ultimately to humans.” – Climate News Network


Europe warns of Brazilian trade boycott over fires

Appalled by more forest loss and worse wildfires, eight European countries warn of a possible Brazilian trade boycott.

SÃO PAULO, 21 September, 2020 − There was international concern over the forest fires which swept the Amazon last year. This year’s devastation looks set to be still more severe. And it won’t go without vigorous protest, and possible action: a Brazilian trade boycott.

Six EU countries and the UK have sent an open letter to the Brazilian government protesting at Brazil’s environmental policy and threatening a boycott.

Fires in two of Brazil’s most important biomes (areas of the Earth  that can be classified according to the plants and animals that live in them), the Amazon rainforest and the Pantanal, the world’s largest tropical wetlands area, have reached record numbers of fires.

The seven countries (Germany, France, the Netherlands, Norway, Denmark, Italy, and the United Kingdom), are signatories to the Amsterdam Declarations Partnership, set up in 2015 to ensure sustainable commodity supply chains. Their focus is on deforestation and sustainable palm oil.

Worse than 2019

Their letter (which is supported by a non-member of the Partnership, Belgium) was prompted by evidence that this year’s fires in the Amazon are going to be even worse than those last year, which led to worldwide protests against the Brazilian government. In the first two weeks of September 2020 more fires have been recorded than during the entire month of September last year.

In addition, not only is the Amazon burning: the Pantanal is also seeing a record number of fires. An area the size of Belgium (almost 3 million hectares) has already been burnt. The Pantanal is a wildlife sanctuary, and untold millions of animals, birds and reptiles have been burned to death or have died from smoke inhalation, in what is probably one of the worst-ever extinctions of wildlife.

The fires in the Pantanal have been facilitated by an unprecedented drought, leaving rivers and streams dry, but police are investigating evidence that they were started deliberately by farmers seeking more grassland for their cattle. The Pantanal is also home to millions of cattle.

The letter’s signatories express alarm at the growth in deforestation which has led to the fires, pointing out that in the past Brazil successfully expanded agricultural production while reducing forest clearing.

Supermarkets intervene

“There is growing concern among consumers, companies, investors and European civil society about the present rates of deforestation”, they say.

Recently two of Germany’s biggest supermarket chains, Edeka and Lidl, asked the German government to put pressure on Brazil to reduce deforestation.

For Marcio Astrini, of the Brazilian NGO Climate Observatory, the letter will influence the EU-Mercosur trade deal, which still has to be ratified by most European parliaments.

“Jair Bolsonaro and his government are destroying our biomes, the Earth’s climate and the economic future of the country in the name of a toxic and stupid ideology, which favours environmental crime in detriment to productive forces and the comparative advantages which Brazil enjoyed”, he said.

Global protest

President Bolsonaro and his ministers, who against all the evidence continue to deny the severity of the fires in the Amazon, downplayed the importance of the letter, dismissing it as a “trade strategy” of the Europeans.

But it is not only the Europeans who are worried about what’s happening in the Amazon. A few days ago 230 agribusiness companies and NGOs joined forces to present the government with a list of proposals for ending deforestation (in Brazilian Portuguese)

The group, which includes WWF Brazil, the World Resources Institute, Imazon and Instituto de Pesquisa Ambiental da Amazônia (IPAM), as well as some of the world’s biggest agribusiness companies, like Bayer, Danone, Unilever, Natura, JBS, Marfrig and Amaggi, says that a rapid decrease in deforestation is fundamental, not only for environmental but for economic reasons too.

It wants a return to regular monitoring and application of fines for illegal clearing, which the Bolsonaro government has effectively sabotaged by cutting funds for environmental agencies.

“Jair Bolsonaro and his government are destroying our biomes, the Earth’s climate and the economic future of the country in the name of a toxic and stupid ideology”

It says access to official funds should be conditional upon socio-environmental criteria, and attempts by private landowners to declare themselves owners of areas located within protected public lands should be stopped.

In other words, what it is demanding is not rocket science, but the enforcement of existing laws, instead of the illegality which the Bolsonaro government has indirectly encouraged.

Neither the Amazon nor the Pantanal, both humid areas, catches fire spontaneously. Huge areas illegally cleared last year are being set on fire to prepare the land for farming. Trees were felled en masse by big chains stretched between tractors that topple everything in their path.

This year the felled vegetation is being burned to clear the land for cattle or soy. Between January 2019 and April 2020 an area of over 4,500 sq kms of Amazon forest was cleared.

Catastrophe foretold

The fires spread easily because of tinder-dry conditions, and because the environment ministry failed to release funds for firefighting until the dry season was well under way.

There were warnings. In June IPAM declared that the deforestation of the last year and a half in the Amazon could herald a catastrophe in the region. “If 100% is burnt, an unprecedented health calamity will add to the effects of Covid-19”, it said.

The fires have covered towns and cities in the Amazon with huge clouds of sooty smoke, leading to thousands of people, including babies and small children, being hospitalised for breathing problems, as reported in a study published by Human Rights Watch, IPAM and IPES (the Health Policies Study Institute), on 26 August.

The fires’ impact is not confined to the Amazon region: black clouds of sooty particles are spreading south and are expected to reach São Paulo, Brazil’s major metropolis, within a few days. Pressure for a Brazilian trade boycott is liable to intensify. − Climate News Network

Appalled by more forest loss and worse wildfires, eight European countries warn of a possible Brazilian trade boycott.

SÃO PAULO, 21 September, 2020 − There was international concern over the forest fires which swept the Amazon last year. This year’s devastation looks set to be still more severe. And it won’t go without vigorous protest, and possible action: a Brazilian trade boycott.

Six EU countries and the UK have sent an open letter to the Brazilian government protesting at Brazil’s environmental policy and threatening a boycott.

Fires in two of Brazil’s most important biomes (areas of the Earth  that can be classified according to the plants and animals that live in them), the Amazon rainforest and the Pantanal, the world’s largest tropical wetlands area, have reached record numbers of fires.

The seven countries (Germany, France, the Netherlands, Norway, Denmark, Italy, and the United Kingdom), are signatories to the Amsterdam Declarations Partnership, set up in 2015 to ensure sustainable commodity supply chains. Their focus is on deforestation and sustainable palm oil.

Worse than 2019

Their letter (which is supported by a non-member of the Partnership, Belgium) was prompted by evidence that this year’s fires in the Amazon are going to be even worse than those last year, which led to worldwide protests against the Brazilian government. In the first two weeks of September 2020 more fires have been recorded than during the entire month of September last year.

In addition, not only is the Amazon burning: the Pantanal is also seeing a record number of fires. An area the size of Belgium (almost 3 million hectares) has already been burnt. The Pantanal is a wildlife sanctuary, and untold millions of animals, birds and reptiles have been burned to death or have died from smoke inhalation, in what is probably one of the worst-ever extinctions of wildlife.

The fires in the Pantanal have been facilitated by an unprecedented drought, leaving rivers and streams dry, but police are investigating evidence that they were started deliberately by farmers seeking more grassland for their cattle. The Pantanal is also home to millions of cattle.

The letter’s signatories express alarm at the growth in deforestation which has led to the fires, pointing out that in the past Brazil successfully expanded agricultural production while reducing forest clearing.

Supermarkets intervene

“There is growing concern among consumers, companies, investors and European civil society about the present rates of deforestation”, they say.

Recently two of Germany’s biggest supermarket chains, Edeka and Lidl, asked the German government to put pressure on Brazil to reduce deforestation.

For Marcio Astrini, of the Brazilian NGO Climate Observatory, the letter will influence the EU-Mercosur trade deal, which still has to be ratified by most European parliaments.

“Jair Bolsonaro and his government are destroying our biomes, the Earth’s climate and the economic future of the country in the name of a toxic and stupid ideology, which favours environmental crime in detriment to productive forces and the comparative advantages which Brazil enjoyed”, he said.

Global protest

President Bolsonaro and his ministers, who against all the evidence continue to deny the severity of the fires in the Amazon, downplayed the importance of the letter, dismissing it as a “trade strategy” of the Europeans.

But it is not only the Europeans who are worried about what’s happening in the Amazon. A few days ago 230 agribusiness companies and NGOs joined forces to present the government with a list of proposals for ending deforestation (in Brazilian Portuguese)

The group, which includes WWF Brazil, the World Resources Institute, Imazon and Instituto de Pesquisa Ambiental da Amazônia (IPAM), as well as some of the world’s biggest agribusiness companies, like Bayer, Danone, Unilever, Natura, JBS, Marfrig and Amaggi, says that a rapid decrease in deforestation is fundamental, not only for environmental but for economic reasons too.

It wants a return to regular monitoring and application of fines for illegal clearing, which the Bolsonaro government has effectively sabotaged by cutting funds for environmental agencies.

“Jair Bolsonaro and his government are destroying our biomes, the Earth’s climate and the economic future of the country in the name of a toxic and stupid ideology”

It says access to official funds should be conditional upon socio-environmental criteria, and attempts by private landowners to declare themselves owners of areas located within protected public lands should be stopped.

In other words, what it is demanding is not rocket science, but the enforcement of existing laws, instead of the illegality which the Bolsonaro government has indirectly encouraged.

Neither the Amazon nor the Pantanal, both humid areas, catches fire spontaneously. Huge areas illegally cleared last year are being set on fire to prepare the land for farming. Trees were felled en masse by big chains stretched between tractors that topple everything in their path.

This year the felled vegetation is being burned to clear the land for cattle or soy. Between January 2019 and April 2020 an area of over 4,500 sq kms of Amazon forest was cleared.

Catastrophe foretold

The fires spread easily because of tinder-dry conditions, and because the environment ministry failed to release funds for firefighting until the dry season was well under way.

There were warnings. In June IPAM declared that the deforestation of the last year and a half in the Amazon could herald a catastrophe in the region. “If 100% is burnt, an unprecedented health calamity will add to the effects of Covid-19”, it said.

The fires have covered towns and cities in the Amazon with huge clouds of sooty smoke, leading to thousands of people, including babies and small children, being hospitalised for breathing problems, as reported in a study published by Human Rights Watch, IPAM and IPES (the Health Policies Study Institute), on 26 August.

The fires’ impact is not confined to the Amazon region: black clouds of sooty particles are spreading south and are expected to reach São Paulo, Brazil’s major metropolis, within a few days. Pressure for a Brazilian trade boycott is liable to intensify. − Climate News Network

Seas and forests are muddying the carbon budget

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

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

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

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

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

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

Forest doubts

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

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

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

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

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

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

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

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

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

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

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

Oceans’ effect

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

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

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

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

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

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

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

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

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

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

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

Forest doubts

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

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

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

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

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

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

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

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

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

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

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

Oceans’ effect

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

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

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

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

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