Category Archives: Nature

Warming puts surviving great tits in jeopardy

Among the best loved and most frequent visitors to gardens in the UK and elsewhere, great tits face mounting problems.

LONDON, 19 November, 2020 – In the scientific community great tits are known as one of the most adaptable of bird species, showing considerable ability in adjusting to changing weather patterns and differing times of food supplies.

But latest research indicates that even these ever-enterprising and resilient birds are coming under growing pressure from global heating.

“Wildlife has shown a great ability to adapt to climate change”, Emily Simmonds, lead author of a study of great tits and their food supplies, told Climate News Network.

“So far the great tit has shown a remarkable degree of adaptation to changes in climate. The problem occurs when change happens too fast – then, at some point in the future, the species could become extinct.”

“Our projections suggest that current population stability could be masking a route to population collapse”

Research by Simmonds and her colleagues involved both complex mathematical modelling and extensive fieldwork. Its main focus was to establish how quickly great tits could adapt to changes in the supply of caterpillars or larvae, vital food for the birds’ hatchlings.

Differing climate scenarios were used. In warmer conditions spring can occur earlier, with trees coming into leaf sooner than usual. This, in turn, causes larvae that feed on plants and leaves to hatch out earlier.

The problem is that if at some stage great tits fail to keep pace with these changes, then there will be no food for the hatchlings.

“If greenhouse gas emissions are too high and there’s more warming, then great tits might not be able to adjust their breeding habits quickly enough in order to adapt to the earlier supply of larvae”, says Simmonds.

Too fast for survival

“So far it seems that the birds are coping, but if warming continues at its present pace then it could be too much for them.”

Simmonds, now at the Norwegian University of Science and Technology,  carried out her research at Oxford in the UK.

At Wytham Woods outside Oxford scientists have been recording the nesting and breeding habits of the great tit – Parus major – and the blue tit – Cyanistes caeruleus – since 1947. Up to 40 generations of birds have been marked in what is one of the longest-running ecological studies of wild animals in the world.

The recent study looked at great tits’ reproduction success rates, hatching dates and inheritance factors – the ability of one generation to pass on to the next changes in breeding and feeding patterns.

Safety threshold

Winter temperatures, rainfall patterns and the availability of food supplies under different climate projections were considered.

“The good news is that populations of great tits can survive and adapt to scenarios with lower or medium warming trends”, says Simmonds.

But the study found that if warming trends continue at present levels, with larvae appearing, by the end of the century, about 24 days earlier than at present, great tit populations could become extinct.

“Our projections suggest that current population stability could be masking a route to population collapse, if high greenhouse gas emissions continue”, the study says. – Climate News Network

Among the best loved and most frequent visitors to gardens in the UK and elsewhere, great tits face mounting problems.

LONDON, 19 November, 2020 – In the scientific community great tits are known as one of the most adaptable of bird species, showing considerable ability in adjusting to changing weather patterns and differing times of food supplies.

But latest research indicates that even these ever-enterprising and resilient birds are coming under growing pressure from global heating.

“Wildlife has shown a great ability to adapt to climate change”, Emily Simmonds, lead author of a study of great tits and their food supplies, told Climate News Network.

“So far the great tit has shown a remarkable degree of adaptation to changes in climate. The problem occurs when change happens too fast – then, at some point in the future, the species could become extinct.”

“Our projections suggest that current population stability could be masking a route to population collapse”

Research by Simmonds and her colleagues involved both complex mathematical modelling and extensive fieldwork. Its main focus was to establish how quickly great tits could adapt to changes in the supply of caterpillars or larvae, vital food for the birds’ hatchlings.

Differing climate scenarios were used. In warmer conditions spring can occur earlier, with trees coming into leaf sooner than usual. This, in turn, causes larvae that feed on plants and leaves to hatch out earlier.

The problem is that if at some stage great tits fail to keep pace with these changes, then there will be no food for the hatchlings.

“If greenhouse gas emissions are too high and there’s more warming, then great tits might not be able to adjust their breeding habits quickly enough in order to adapt to the earlier supply of larvae”, says Simmonds.

Too fast for survival

“So far it seems that the birds are coping, but if warming continues at its present pace then it could be too much for them.”

Simmonds, now at the Norwegian University of Science and Technology,  carried out her research at Oxford in the UK.

At Wytham Woods outside Oxford scientists have been recording the nesting and breeding habits of the great tit – Parus major – and the blue tit – Cyanistes caeruleus – since 1947. Up to 40 generations of birds have been marked in what is one of the longest-running ecological studies of wild animals in the world.

The recent study looked at great tits’ reproduction success rates, hatching dates and inheritance factors – the ability of one generation to pass on to the next changes in breeding and feeding patterns.

Safety threshold

Winter temperatures, rainfall patterns and the availability of food supplies under different climate projections were considered.

“The good news is that populations of great tits can survive and adapt to scenarios with lower or medium warming trends”, says Simmonds.

But the study found that if warming trends continue at present levels, with larvae appearing, by the end of the century, about 24 days earlier than at present, great tit populations could become extinct.

“Our projections suggest that current population stability could be masking a route to population collapse, if high greenhouse gas emissions continue”, the study says. – Climate News Network

Shrinking world leaves less room for wild creatures

Wild creatures are losing their range. One day jaguars and rhinos, pandas and tigers, may have nowhere left to go.

LONDON, 18 November, 2020 − Thanks to climate change and to the human colonisation of the natural landscape, the world’s wild creatures have vanishing space in which to roam. In the last two centuries birds, mammals and amphibians have lost − this is an average figure − almost a fifth of their natural range.

By the close of the century, this freedom will have been limited even more, by almost a fourth of their living space. That is a conclusion based on close observation by generations of naturalists since 1700, of almost 17,000 species on all the main continents. And those figures, remember, are simply averages.

Individual species may have lost much, much more of the habitat and climate regime on which they depend to survive. According to the International Union for Conservation of Nature’s species Red List the jaguar has lost 21% of its living space; the cheetah 28%; the black rhinoceros 53%.

Even those charismatic creatures slow in movement and static of habit have felt the confinement. The panda has 11% less freedom. The koala’s range has been reduced by 22%.

Tropics hit hardest

And despite decades of conservation effort, the Bengal tiger’s hunting grounds have been diminished by a fifth.

“The habitat size of almost all known birds, mammals and amphibians is shrinking, primarily because of land conversion by humans as we continue to expand our agricultural and urban areas,” said Robert Beyer, a zoologist at the University of Cambridge in the UK, first author of the study, in the journal Nature Communications, of the habitat of 16,919 animals.

One in six of these has already lost half its estimated natural range. By 2100, it could be more than one in four, depending on a range of climate scenarios.

The swiftest and most dramatic changes have been in the tropical zones, as wilderness has given way to palm oil plantation or cattle range. In many cases, the tropical species’ ranges were smaller to begin with.

“The habitat size of almost all known birds, mammals and amphibians is shrinking, primarily because of land conversion by humans as we continue to expand our agricultural and urban areas”

“The tropics are biodiversity hotspots with lots of small-range species. If one hectare of forest is converted to agricultural land, a lot more species lose larger proportions of their home than in places like Europe,” Dr Beyer said.

“Species in the Amazon have adapted to living in tropical rainforest. If climate change causes this ecosystem to change, many of those species won’t be able to survive − or they will be pushed into smaller areas of remaining rainforest. We found that the higher the carbon emissions, the worse it gets for most species in terms of habitat loss.”

Researchers have calculated that perhaps a million species could be threatened with extinction as a consequence of the human conversion of wilderness and human-fuelled climate change. Cambridge co-author Andrea Manica warned that what happens to the creatures of the tropical wilderness will depend on just how much more fossil fuels humans burn, and how rapaciously human intruders scorch and clear the forests and grasslands.

“While our study quantifies the drastic consequences for species’ ranges, if global land use and climate change are left unchecked, it also demonstrates the tremendous potential of timely and concerted policy action for halting − and indeed reversing − previous trends in global range contractions,” he said.

“It all depends on what we do next.” Remembering the needs of the wild creatures who share the planet would be a start. − Climate News Network

Wild creatures are losing their range. One day jaguars and rhinos, pandas and tigers, may have nowhere left to go.

LONDON, 18 November, 2020 − Thanks to climate change and to the human colonisation of the natural landscape, the world’s wild creatures have vanishing space in which to roam. In the last two centuries birds, mammals and amphibians have lost − this is an average figure − almost a fifth of their natural range.

By the close of the century, this freedom will have been limited even more, by almost a fourth of their living space. That is a conclusion based on close observation by generations of naturalists since 1700, of almost 17,000 species on all the main continents. And those figures, remember, are simply averages.

Individual species may have lost much, much more of the habitat and climate regime on which they depend to survive. According to the International Union for Conservation of Nature’s species Red List the jaguar has lost 21% of its living space; the cheetah 28%; the black rhinoceros 53%.

Even those charismatic creatures slow in movement and static of habit have felt the confinement. The panda has 11% less freedom. The koala’s range has been reduced by 22%.

Tropics hit hardest

And despite decades of conservation effort, the Bengal tiger’s hunting grounds have been diminished by a fifth.

“The habitat size of almost all known birds, mammals and amphibians is shrinking, primarily because of land conversion by humans as we continue to expand our agricultural and urban areas,” said Robert Beyer, a zoologist at the University of Cambridge in the UK, first author of the study, in the journal Nature Communications, of the habitat of 16,919 animals.

One in six of these has already lost half its estimated natural range. By 2100, it could be more than one in four, depending on a range of climate scenarios.

The swiftest and most dramatic changes have been in the tropical zones, as wilderness has given way to palm oil plantation or cattle range. In many cases, the tropical species’ ranges were smaller to begin with.

“The habitat size of almost all known birds, mammals and amphibians is shrinking, primarily because of land conversion by humans as we continue to expand our agricultural and urban areas”

“The tropics are biodiversity hotspots with lots of small-range species. If one hectare of forest is converted to agricultural land, a lot more species lose larger proportions of their home than in places like Europe,” Dr Beyer said.

“Species in the Amazon have adapted to living in tropical rainforest. If climate change causes this ecosystem to change, many of those species won’t be able to survive − or they will be pushed into smaller areas of remaining rainforest. We found that the higher the carbon emissions, the worse it gets for most species in terms of habitat loss.”

Researchers have calculated that perhaps a million species could be threatened with extinction as a consequence of the human conversion of wilderness and human-fuelled climate change. Cambridge co-author Andrea Manica warned that what happens to the creatures of the tropical wilderness will depend on just how much more fossil fuels humans burn, and how rapaciously human intruders scorch and clear the forests and grasslands.

“While our study quantifies the drastic consequences for species’ ranges, if global land use and climate change are left unchecked, it also demonstrates the tremendous potential of timely and concerted policy action for halting − and indeed reversing − previous trends in global range contractions,” he said.

“It all depends on what we do next.” Remembering the needs of the wild creatures who share the planet would be a start. − Climate News Network

Climate crisis finds ample answers in world’s trees

The world’s trees can build cities, devour carbon and feed developing countries’ small farmers. It’s time to branch out.

LONDON, 17 November, 2020 − The great climate change challenge should consider the world’s trees. New wooden cities and suburbs − that is, new homes fashioned from wood rather than bricks and mortar − could consume 55 million tonnes of carbon dioxide (CO2) a year: that adds up to almost half of the annual greenhouse gas emissions from Europe’s cement industry.

And the bigger and more substantial the tree, the more value in the arboreal effort to limit global warming and contain climate change. A US study has found that large trees − those with trunks of 53 cms at breast height − might make up only 3% of a measured plot, but contain 42% of all the above-ground carbon.

And trees could enhance human health as well as capture carbon: an international team believes that tree-sourced food − think mangoes, avocados, Brazil nuts and so on − could deliver much more nourishment for tomorrow’s supper tables.

The planet is home to at least 7,000 edible plants. Half the world’s calories come from just four crops, all high in calories but low in nutrients − wheat, rice, sugar cane and maize − that simultaneously fuel both malnutrition and obesity. There are 50,000 tree species in the tropics alone, a number of them potentially new sources of high quality food.

The conclusions of all three studies are tentative. But they are also familiar: that is, other research teams have for years been investigating trees as fabric, trees as absorbers of atmospheric carbon, and trees as enhanced forms of farming.

“This is the first time that the carbon storage potential of wooden building construction has been evaluated on the European level”

But all three offer a new and more detailed look, and confirm the big picture: when it comes to climate, the world’s trees are among the most important things on the planet.

Finnish scientists report in the journal Environmental Research Letters that they looked again at 50 case studies of timber as a way of growing cities: Europe builds about 190 million square metres of housing each year, largely in cities, and this demand for new homes is growing at 1% a year. Buildings worldwide − concrete, steel, glass, bricks, tiles, paving and so on − account for one third of global greenhouse gas emissions.

If however 80% of new residential buildings in Europe were built of, clad with and furnished from timber from sustainable forests, then this could represent a carbon sink of 55 million tonnes of CO2 a year, represent a 47% cut in greenhouse gas emissions from Europe’s cement-makers, and deliver energy-efficient homes.

“This is the first time that the carbon storage potential of wooden building construction has been evaluated on the European level, in different scenarios,” said Ali Amiri, of Aalto University, who led the study. “We hope that our model could be used as a roadmap to increase wooden construction in Europe.”

US scientists report in the journal Frontiers in Forests and Global Change that they took a close look at large diameter trees on National Forest lands in the states of Oregon and Washington.

Size matters

Trees with diameters greater than 21 inches, or 53.3 cms, accounted for only 3% of the total number of trees in the plots they chose to study. But when it came to absorbing atmospheric carbon, these were the real heavyweights. They contained 42% of all the above-ground carbon in the entire measured ecosystem.

Trees bigger than 30 inches, or 76 cms in diameter, made up only 0.6% of the total number, but accounted for 16% of the total above-ground carbon. The message was, the bigger the better.

The forest giants are themselves natural habitat: they support birds, mammals, insects, microbes and other plants; they serve as soaring water towers, tapping groundwater and cooling the environment through evotranspiration. And their value as a store of atmospheric carbon has been confirmed again and again.

“If you think of adding a ring of new growth to the circumference of a large tree and its branches every year, that ring adds up to a lot more carbon than the ring of a small tree,” said David Mildrexler, of Eastern Oregon Legacy Lands, who led the research. “This is why specifically letting large trees grow larger is important for climate change.”

And trees, researchers from five nations argue in the journal People and Nature, could be the healthy solution both to the climate crisis and to poor diet.

Better fed

Of the world’s 100 most nourishing foods, 14 come from trees. The planet is home to 60,000 species of tree, and many − especially in the tropics − provide nutritious fruits, nuts, leaves and seeds. Many are exploited only by small rural communities.

In the Amazon basin, for instance, a shrub called Myrciaria dubia was found to have a vitamin C content 54 times that of an orange. The scientists looked at seven tropical nations to identify foods from 90 tree species: these provided local families with 11% of diet by mass but 31% of the daily intake of vitamins A and C.

Never mind the giant commercial palm oil plantations and cacao harvests: the researchers see tree crops as something that could sustainably help hundreds of millions of the world’s smallholder farmers, by diversifying income and providing more and healthier food with a very low investment.

“The right type of trees in the right place can provide nutritious foods to improve diets sustainably while providing other valuable ecosystem services such as carbon sequestration,” said Merel Jansen, of the Swiss Federal Institute of Technology known as ETH Zurich, who led the investigation.

“It can also contribute to development issues related to poverty reduction, biodiversity conservation, and food security.” − Climate News Network

The world’s trees can build cities, devour carbon and feed developing countries’ small farmers. It’s time to branch out.

LONDON, 17 November, 2020 − The great climate change challenge should consider the world’s trees. New wooden cities and suburbs − that is, new homes fashioned from wood rather than bricks and mortar − could consume 55 million tonnes of carbon dioxide (CO2) a year: that adds up to almost half of the annual greenhouse gas emissions from Europe’s cement industry.

And the bigger and more substantial the tree, the more value in the arboreal effort to limit global warming and contain climate change. A US study has found that large trees − those with trunks of 53 cms at breast height − might make up only 3% of a measured plot, but contain 42% of all the above-ground carbon.

And trees could enhance human health as well as capture carbon: an international team believes that tree-sourced food − think mangoes, avocados, Brazil nuts and so on − could deliver much more nourishment for tomorrow’s supper tables.

The planet is home to at least 7,000 edible plants. Half the world’s calories come from just four crops, all high in calories but low in nutrients − wheat, rice, sugar cane and maize − that simultaneously fuel both malnutrition and obesity. There are 50,000 tree species in the tropics alone, a number of them potentially new sources of high quality food.

The conclusions of all three studies are tentative. But they are also familiar: that is, other research teams have for years been investigating trees as fabric, trees as absorbers of atmospheric carbon, and trees as enhanced forms of farming.

“This is the first time that the carbon storage potential of wooden building construction has been evaluated on the European level”

But all three offer a new and more detailed look, and confirm the big picture: when it comes to climate, the world’s trees are among the most important things on the planet.

Finnish scientists report in the journal Environmental Research Letters that they looked again at 50 case studies of timber as a way of growing cities: Europe builds about 190 million square metres of housing each year, largely in cities, and this demand for new homes is growing at 1% a year. Buildings worldwide − concrete, steel, glass, bricks, tiles, paving and so on − account for one third of global greenhouse gas emissions.

If however 80% of new residential buildings in Europe were built of, clad with and furnished from timber from sustainable forests, then this could represent a carbon sink of 55 million tonnes of CO2 a year, represent a 47% cut in greenhouse gas emissions from Europe’s cement-makers, and deliver energy-efficient homes.

“This is the first time that the carbon storage potential of wooden building construction has been evaluated on the European level, in different scenarios,” said Ali Amiri, of Aalto University, who led the study. “We hope that our model could be used as a roadmap to increase wooden construction in Europe.”

US scientists report in the journal Frontiers in Forests and Global Change that they took a close look at large diameter trees on National Forest lands in the states of Oregon and Washington.

Size matters

Trees with diameters greater than 21 inches, or 53.3 cms, accounted for only 3% of the total number of trees in the plots they chose to study. But when it came to absorbing atmospheric carbon, these were the real heavyweights. They contained 42% of all the above-ground carbon in the entire measured ecosystem.

Trees bigger than 30 inches, or 76 cms in diameter, made up only 0.6% of the total number, but accounted for 16% of the total above-ground carbon. The message was, the bigger the better.

The forest giants are themselves natural habitat: they support birds, mammals, insects, microbes and other plants; they serve as soaring water towers, tapping groundwater and cooling the environment through evotranspiration. And their value as a store of atmospheric carbon has been confirmed again and again.

“If you think of adding a ring of new growth to the circumference of a large tree and its branches every year, that ring adds up to a lot more carbon than the ring of a small tree,” said David Mildrexler, of Eastern Oregon Legacy Lands, who led the research. “This is why specifically letting large trees grow larger is important for climate change.”

And trees, researchers from five nations argue in the journal People and Nature, could be the healthy solution both to the climate crisis and to poor diet.

Better fed

Of the world’s 100 most nourishing foods, 14 come from trees. The planet is home to 60,000 species of tree, and many − especially in the tropics − provide nutritious fruits, nuts, leaves and seeds. Many are exploited only by small rural communities.

In the Amazon basin, for instance, a shrub called Myrciaria dubia was found to have a vitamin C content 54 times that of an orange. The scientists looked at seven tropical nations to identify foods from 90 tree species: these provided local families with 11% of diet by mass but 31% of the daily intake of vitamins A and C.

Never mind the giant commercial palm oil plantations and cacao harvests: the researchers see tree crops as something that could sustainably help hundreds of millions of the world’s smallholder farmers, by diversifying income and providing more and healthier food with a very low investment.

“The right type of trees in the right place can provide nutritious foods to improve diets sustainably while providing other valuable ecosystem services such as carbon sequestration,” said Merel Jansen, of the Swiss Federal Institute of Technology known as ETH Zurich, who led the investigation.

“It can also contribute to development issues related to poverty reduction, biodiversity conservation, and food security.” − 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

Carbon release set off Earth’s biggest extinction

A chain of calamities caused the planet’s biggest extinction, the greatest mass dying ever. Greenhouse gases explain how.

LONDON, 23 October, 2020 − German scientists are now sure they can explain the biggest extinction of life on this planet: a catastrophe at the end of the Permian Epoch 252 million years ago.

It happened because atmospheric carbon dioxide (CO2) levels rose dramatically over thousands of years, turning the seas ever more acidic, to precipitate dangerous changes in oceanic conditions. In this, so far the greatest of life’s periodic extinctions, 95% of all the sea creatures perished, along with three-quarters of all life on land.

The evidence of dramatic change at a particular level in the geological record − the Permian-Triassic boundary, now more precisely dated at 251.9 million years ago − has been teasing geologists for decades. And climate change through one agency or another has been a favoured candidate from the start.

That moment in vanished history was marked by a long, slow but world-changing series of volcanic eruptions − the evidence lies in great sheets of basalt known to geologists as the Siberian Traps − and since outgassing of carbon dioxide is associated with all volcanic eruption, a greenhouse effect driven by carbon dioxide has long been a favourite.

Seeking proof

So devastating was this release of heat from the deep crust that ancient coal deposits laid down in the Carboniferous may have ignited, to create the first-ever fossil fuel emissions.

But circumstantial evidence was not the same thing as proof. Dramatic ozone loss − ozone forms a shield against potentially lethal ultra-violet radiation in the upper atmosphere − has also been named as a suspect. Until somebody could deliver clear evidence of the machinery that ensured the extinction, the verdict could only be “not proven.”

Right now, with human help, the planet Earth is undergoing what has been termed a sixth great mass extinction, and evidence from the Permian extinction provides a lesson for what could happen in a changing climate, but so far simply that: an awful warning, rather than a dreadful example.

Now European researchers report in Nature Geoscience that they think they have settled the matter. They used evidence from fossils exposed in the Italian Alps to recreate the conditions in the ancient ocean.

“Humanity’s CO2 emission rate is currently fourteen times higher than the annual emission rate at the time that marked the greatest biological catastrophe in Earth’s history”

The story told by the changing isotopes of carbon, oxygen and most importantly boron in a series of brachiopod fossils was of “substantial” change in the chemistry of sea water 252 million years ago: a change that could be linked to the carbon dioxide from the Siberian Traps eruptions.

The researchers took the reasoning a step further: they used computer models to simulate the conditions of the time. The world warmed, the oceans became increasingly acidic, and right at the outset those organisms in the sea that build shells from calcium were snuffed out of existence.

But the higher temperatures, greater evaporation and ever-higher rainfall that mark a greenhouse world meant ever-greater chemical weathering on land itself. So more nutrients flowed from land to ocean, to deliver too much fertiliser, to encourage too much algal growth.

What followed was a dramatic depletion of dissolved oxygen: marine life was increasingly stifled, or poisoned by sporadic sulphide concentration.

Chain reaction

“We are dealing with a cascading catastrophe in which the rise of CO2 in the atmosphere set off a chain of events that successively extinguished almost all life in the seas,” said Hana Jurikova, then of the Helmholtz Centre for Ocean Research in Kiel, Germany, but now at St Andrew’s in Scotland, who led the study.

It is an axiom of geological research that the present is key to the past, but her forensic account of ancient mayhem may not be a precise lesson for today.

“Ancient volcanic eruptions of this kind are not directly comparable to anthropogenic carbon emissions, and in fact all modern fossil fuel reserves are far too insufficient to release as much CO2 over hundreds of years, let alone thousands of years as was released 252 million years ago,” said Dr Jurikova.

“But it is astonishing that humanity’s CO2 emission rate is currently fourteen times higher than the annual emission rate at the time that marked the greatest biological catastrophe in Earth’s history”. − Climate News Network

A chain of calamities caused the planet’s biggest extinction, the greatest mass dying ever. Greenhouse gases explain how.

LONDON, 23 October, 2020 − German scientists are now sure they can explain the biggest extinction of life on this planet: a catastrophe at the end of the Permian Epoch 252 million years ago.

It happened because atmospheric carbon dioxide (CO2) levels rose dramatically over thousands of years, turning the seas ever more acidic, to precipitate dangerous changes in oceanic conditions. In this, so far the greatest of life’s periodic extinctions, 95% of all the sea creatures perished, along with three-quarters of all life on land.

The evidence of dramatic change at a particular level in the geological record − the Permian-Triassic boundary, now more precisely dated at 251.9 million years ago − has been teasing geologists for decades. And climate change through one agency or another has been a favoured candidate from the start.

That moment in vanished history was marked by a long, slow but world-changing series of volcanic eruptions − the evidence lies in great sheets of basalt known to geologists as the Siberian Traps − and since outgassing of carbon dioxide is associated with all volcanic eruption, a greenhouse effect driven by carbon dioxide has long been a favourite.

Seeking proof

So devastating was this release of heat from the deep crust that ancient coal deposits laid down in the Carboniferous may have ignited, to create the first-ever fossil fuel emissions.

But circumstantial evidence was not the same thing as proof. Dramatic ozone loss − ozone forms a shield against potentially lethal ultra-violet radiation in the upper atmosphere − has also been named as a suspect. Until somebody could deliver clear evidence of the machinery that ensured the extinction, the verdict could only be “not proven.”

Right now, with human help, the planet Earth is undergoing what has been termed a sixth great mass extinction, and evidence from the Permian extinction provides a lesson for what could happen in a changing climate, but so far simply that: an awful warning, rather than a dreadful example.

Now European researchers report in Nature Geoscience that they think they have settled the matter. They used evidence from fossils exposed in the Italian Alps to recreate the conditions in the ancient ocean.

“Humanity’s CO2 emission rate is currently fourteen times higher than the annual emission rate at the time that marked the greatest biological catastrophe in Earth’s history”

The story told by the changing isotopes of carbon, oxygen and most importantly boron in a series of brachiopod fossils was of “substantial” change in the chemistry of sea water 252 million years ago: a change that could be linked to the carbon dioxide from the Siberian Traps eruptions.

The researchers took the reasoning a step further: they used computer models to simulate the conditions of the time. The world warmed, the oceans became increasingly acidic, and right at the outset those organisms in the sea that build shells from calcium were snuffed out of existence.

But the higher temperatures, greater evaporation and ever-higher rainfall that mark a greenhouse world meant ever-greater chemical weathering on land itself. So more nutrients flowed from land to ocean, to deliver too much fertiliser, to encourage too much algal growth.

What followed was a dramatic depletion of dissolved oxygen: marine life was increasingly stifled, or poisoned by sporadic sulphide concentration.

Chain reaction

“We are dealing with a cascading catastrophe in which the rise of CO2 in the atmosphere set off a chain of events that successively extinguished almost all life in the seas,” said Hana Jurikova, then of the Helmholtz Centre for Ocean Research in Kiel, Germany, but now at St Andrew’s in Scotland, who led the study.

It is an axiom of geological research that the present is key to the past, but her forensic account of ancient mayhem may not be a precise lesson for today.

“Ancient volcanic eruptions of this kind are not directly comparable to anthropogenic carbon emissions, and in fact all modern fossil fuel reserves are far too insufficient to release as much CO2 over hundreds of years, let alone thousands of years as was released 252 million years ago,” said Dr Jurikova.

“But it is astonishing that humanity’s CO2 emission rate is currently fourteen times higher than the annual emission rate at the time that marked the greatest biological catastrophe in Earth’s history”. − Climate News Network

Rising heat means more methane, warmer nights

Nights are warmer. So are northern lakes. And farm livestock are at greater risk of disease, thanks to rising heat.

LONDON, 20 October, 2020 − Global warming has already begun to alter the world perceptibly, with rising heat changing daily life for millions of people.

Over more than half the planet’s land surface, nights are now warming at a rate faster than the days, with unpredictable consequences for plant and animal life.

Warmer winters now mean that in Europe, Asia and North America, lakes that would once have frozen over are now increasingly sometimes ice-free even at the darkest moments of the year.

And ever-higher temperatures encourage the spread of infectious diseases, and unexpectedly with that, the hazard of yet more warming.

Increasing parasitic activity among farm animals could mean that infected cattle, sheep and goats can produce up to a third more methane. This natural gas is around 30 times more potent, as a greenhouse gas, than the same volume of carbon dioxide.

“There is evidence that climate change, and warming temperatures in particular, are impacting some infectious diseases and increasing their prevalence”

The long-term consequences of any of these changes are difficult to foresee. British scientists report in the journal Global Change Biology that they searched the fine detail of global temperature, cloud cover, humidity and rainfall worldwide from 1983 to 2017 for any significant pattern of change, and found one.

Over more than half the terrestrial surface of the planet, there was a mean annual difference of at least 0.25°C between daytime and night-time warming.

In some places, days warmed more swiftly than nights. But disproportionately greater night-time warming happened over an area more than twice as large.

The agency at work appeared to be cloud cover: more clouds mean a cooler surface in daylight but a more effective blanket to retain warmth at night. Clear skies tend to mean hotter days and colder nights.

“We demonstrate that greater night-time warming is associated with climate becoming wetter, and this been shown to have important consequences for plant growth, and how species such as insects and mammals interact,” said Daniel Cox of Exeter University, UK, who led the research.

More ice-free lakes

“Conversely, we show that greater daytime warming is associated with drier conditions, combined with greater levels of overall warming, which increases vulnerability to heat stress and dehydration. Species that are only active at night or during the day will be particularly affected.”

Freezing winters play a vital role in the life of a northern lake. Canadian scientists report in the journal Geophysical Research Letters that they analysed almost eight decades of data − from 1939 to 2016 − for 122 lakes in Asia, Europe and America: the lakes included Baikal in Siberia, Geneva in Switzerland and Balaton in Hungary, Champlain and Michigan near the US- Canadian border, and Suwa in Japan, where records extend back to 1443.

They found that ice-free years have become three times more frequent since 1978, and 11% experienced at least one completely ice-free year since 1939. The trend was the same, everywhere they looked.

Lake ice is also vulnerable to rising heat. It is important to the winter recreation industry. It also plays a vital role in lake ecology. Without a sheath of winter ice, lakes stay warmer and stratify earlier to become more vulnerable to toxic algal blooms: this in turn is bad for fish, and for swimmers.

“Lake ice is becoming increasingly absent,” said Alessandro Filazzola of York University, Toronto, who led the study. “Even under low-carbon emissions scenarios, we’re going to have ice-free events.”

Methane’s rapid rise

Methane is a relatively short-lived but highly potent greenhouse gas: in the past decade it has increased rapidly in the atmosphere. About half of this increase comes from farm livestock.

US researchers report in the journal Trends in Ecology and Evolution that they looked at sheep studies to find that animals infected with intestinal worms produced up to 33% more methane per kilogram of food than uninfected animals. Dairy cows with mastitis − a bacterial infection − produce 8% more methane per litre of milk than uninfected animals.

Global livestock production could increase at the rate of 2.7% a year, according to UN forecasts. If so, between 2017 and 2050 methane production will soar by more than 20%. Throw parasitic worm infections into the forecasts and methane emissions from livestock could climb by up to 82% in the same period.

“There is evidence that climate change, and warming temperatures in particular, are impacting some infectious diseases and increasing their prevalence,” said Vanessa Ezenwa of the University of Georgia, first author.

“If that’s happening for livestock diseases, and simultaneously higher prevalence is triggering increased methane release, you could end up with what we call a vicious cycle.” − Climate News Network

Nights are warmer. So are northern lakes. And farm livestock are at greater risk of disease, thanks to rising heat.

LONDON, 20 October, 2020 − Global warming has already begun to alter the world perceptibly, with rising heat changing daily life for millions of people.

Over more than half the planet’s land surface, nights are now warming at a rate faster than the days, with unpredictable consequences for plant and animal life.

Warmer winters now mean that in Europe, Asia and North America, lakes that would once have frozen over are now increasingly sometimes ice-free even at the darkest moments of the year.

And ever-higher temperatures encourage the spread of infectious diseases, and unexpectedly with that, the hazard of yet more warming.

Increasing parasitic activity among farm animals could mean that infected cattle, sheep and goats can produce up to a third more methane. This natural gas is around 30 times more potent, as a greenhouse gas, than the same volume of carbon dioxide.

“There is evidence that climate change, and warming temperatures in particular, are impacting some infectious diseases and increasing their prevalence”

The long-term consequences of any of these changes are difficult to foresee. British scientists report in the journal Global Change Biology that they searched the fine detail of global temperature, cloud cover, humidity and rainfall worldwide from 1983 to 2017 for any significant pattern of change, and found one.

Over more than half the terrestrial surface of the planet, there was a mean annual difference of at least 0.25°C between daytime and night-time warming.

In some places, days warmed more swiftly than nights. But disproportionately greater night-time warming happened over an area more than twice as large.

The agency at work appeared to be cloud cover: more clouds mean a cooler surface in daylight but a more effective blanket to retain warmth at night. Clear skies tend to mean hotter days and colder nights.

“We demonstrate that greater night-time warming is associated with climate becoming wetter, and this been shown to have important consequences for plant growth, and how species such as insects and mammals interact,” said Daniel Cox of Exeter University, UK, who led the research.

More ice-free lakes

“Conversely, we show that greater daytime warming is associated with drier conditions, combined with greater levels of overall warming, which increases vulnerability to heat stress and dehydration. Species that are only active at night or during the day will be particularly affected.”

Freezing winters play a vital role in the life of a northern lake. Canadian scientists report in the journal Geophysical Research Letters that they analysed almost eight decades of data − from 1939 to 2016 − for 122 lakes in Asia, Europe and America: the lakes included Baikal in Siberia, Geneva in Switzerland and Balaton in Hungary, Champlain and Michigan near the US- Canadian border, and Suwa in Japan, where records extend back to 1443.

They found that ice-free years have become three times more frequent since 1978, and 11% experienced at least one completely ice-free year since 1939. The trend was the same, everywhere they looked.

Lake ice is also vulnerable to rising heat. It is important to the winter recreation industry. It also plays a vital role in lake ecology. Without a sheath of winter ice, lakes stay warmer and stratify earlier to become more vulnerable to toxic algal blooms: this in turn is bad for fish, and for swimmers.

“Lake ice is becoming increasingly absent,” said Alessandro Filazzola of York University, Toronto, who led the study. “Even under low-carbon emissions scenarios, we’re going to have ice-free events.”

Methane’s rapid rise

Methane is a relatively short-lived but highly potent greenhouse gas: in the past decade it has increased rapidly in the atmosphere. About half of this increase comes from farm livestock.

US researchers report in the journal Trends in Ecology and Evolution that they looked at sheep studies to find that animals infected with intestinal worms produced up to 33% more methane per kilogram of food than uninfected animals. Dairy cows with mastitis − a bacterial infection − produce 8% more methane per litre of milk than uninfected animals.

Global livestock production could increase at the rate of 2.7% a year, according to UN forecasts. If so, between 2017 and 2050 methane production will soar by more than 20%. Throw parasitic worm infections into the forecasts and methane emissions from livestock could climb by up to 82% in the same period.

“There is evidence that climate change, and warming temperatures in particular, are impacting some infectious diseases and increasing their prevalence,” said Vanessa Ezenwa of the University of Georgia, first author.

“If that’s happening for livestock diseases, and simultaneously higher prevalence is triggering increased methane release, you could end up with what we call a vicious cycle.” − 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

Rivers flood, seas rise – and land faces erosion

Polar melting cannot be separated from farmland soil erosion and estuarine flooding. All are part of climate change.

LONDON, 7 September, 2020 – Climate heating often ensures that calamities don’t come singly: so don’t forget what erosion can do.

In a warmer world the glaciers will melt ever faster to raise global sea levels ever higher. In a wetter world, more and more topsoil will be swept off the farmlands and downriver into the ever-rising seas.

And the pay-off of silt-laden rivers and rising sea levels could be catastrophic floods, as swollen rivers suddenly change course. Since many of the world’s greatest cities are built on river estuaries, lives and economies will be at risk.

Three new studies in two journals deliver a sharp reminder that the consequences of global heating are not straightforward: the world responds to change in unpredictable ways.

First: the melting of the ice sheets and the mountain glaciers. Researchers warn in the journal Nature Climate Change that if the loss of ice from Antarctica, Greenland and the frozen rivers continues, then climate forecasters and government agencies will have to think again: sea levels could rise to at least 17cms higher than the worst predictions so far.

“Avulsions are the earthquakes of rivers. They are sudden and sometimes catastrophic. We are trying to understand where and when the next avulsions will occur”

That means an additional 16 million people at hazard from estuarine floods and storm surges.

In the last 30 years, the flow from the Antarctic ice cap has raised sea levels by 7.2mm, and from Greenland by 10.6mm. Every year, the world’s oceans are 4mm higher than they were the year before.

“Although we anticipated the ice sheets would lose increasing amounts of ice in response to the warming of the oceans and the atmosphere, the rate at which they are melting has accelerated faster than we could have imagined,” said Tom Slater of the University of Leeds, in the UK, who led the research.

“The melting is overtaking the climate models we use to guide us, and we are in danger of being unprepared for the risks posed by sea level rise.”

Dr Slater and his colleagues are the third team to warn in the last month that observations of climate already match the worst-case scenarios dreamed up by forecasters preparing for a range of possible climate outcomes.

Erosion risk rises

The latest reading of glacial melt rates suggests that the risk of storm surges for many of the world’s greatest cities will double by the close of the century. But coastal cities – and the farmers who already work 38% of the terrestrial surface to feed almost 8bn people – have another more immediate problem.

In a warmer world, more water evaporates. In a warmer atmosphere, the capacity of the air to hold moisture also increases, so along with more intense droughts, heavier rainfall is on the way for much of the world. And the heavier the rain, or the more prolonged the drought, the higher the risk of soil erosion.

In 2015 the world’s farmers and foresters watched 43 billion tonnes of topsoil wash away from hillsides or blow away from tilled land and into the sea. By 2070, this burden of silt swept away by water or blown by wind will have risen by between 30% and 66%: probably more than 28 bn tons of additional loss.

This could only impoverish the farmland, according to a study by Swiss scientists in the Proceedings of the National Academy of Sciences. It could also impoverish people, communities and countries. The worst hit could be in the less developed nations of the tropics and subtropics.

But the flow of ever-higher silt levels into ever-rising seas also raises a new hazard: hydrologists call it river avulsion. It’s a simple and natural process. As conditions change, so rivers will naturally change their flow to spill over new floodplains and extend coastal lands.

Survival in question

But river avulsions can also be helped along by rising sea levels. Since 10% of humanity is crowded into rich, fertile delta lands, and since some of the deadliest floods in human history – two in China in 1887 and 1931 claimed six million lives – have been caused by river avulsions, the question becomes a matter of life and death.

US scientists report, also in the Proceedings of the National Academy of Sciences, that rising sea levels alone could make abrupt river avulsion more probable, especially as delta lands could be subsiding, because of groundwater and other extraction.

The dangers of avulsion are affected by the rate of sediment deposit in the river channels, and this is likely to rise with sea levels. This in turn raises the level of the river and eventually a breach of a levee or other flood defence will force the river to find a swifter, steeper path to the sea.

Cities such as New Orleans and the coastal communities of the Mississippi delta are already vulnerable. “Avulsions are the earthquakes of rivers,” said Michael Lamb, of California Institute of Technology, one of the authors.

“They are sudden and sometimes catastrophic natural events that occur with statistical regularity, shifting the direction of major rivers. We are trying to understand where and when the next avulsions will occur.” – Climate News Network

Polar melting cannot be separated from farmland soil erosion and estuarine flooding. All are part of climate change.

LONDON, 7 September, 2020 – Climate heating often ensures that calamities don’t come singly: so don’t forget what erosion can do.

In a warmer world the glaciers will melt ever faster to raise global sea levels ever higher. In a wetter world, more and more topsoil will be swept off the farmlands and downriver into the ever-rising seas.

And the pay-off of silt-laden rivers and rising sea levels could be catastrophic floods, as swollen rivers suddenly change course. Since many of the world’s greatest cities are built on river estuaries, lives and economies will be at risk.

Three new studies in two journals deliver a sharp reminder that the consequences of global heating are not straightforward: the world responds to change in unpredictable ways.

First: the melting of the ice sheets and the mountain glaciers. Researchers warn in the journal Nature Climate Change that if the loss of ice from Antarctica, Greenland and the frozen rivers continues, then climate forecasters and government agencies will have to think again: sea levels could rise to at least 17cms higher than the worst predictions so far.

“Avulsions are the earthquakes of rivers. They are sudden and sometimes catastrophic. We are trying to understand where and when the next avulsions will occur”

That means an additional 16 million people at hazard from estuarine floods and storm surges.

In the last 30 years, the flow from the Antarctic ice cap has raised sea levels by 7.2mm, and from Greenland by 10.6mm. Every year, the world’s oceans are 4mm higher than they were the year before.

“Although we anticipated the ice sheets would lose increasing amounts of ice in response to the warming of the oceans and the atmosphere, the rate at which they are melting has accelerated faster than we could have imagined,” said Tom Slater of the University of Leeds, in the UK, who led the research.

“The melting is overtaking the climate models we use to guide us, and we are in danger of being unprepared for the risks posed by sea level rise.”

Dr Slater and his colleagues are the third team to warn in the last month that observations of climate already match the worst-case scenarios dreamed up by forecasters preparing for a range of possible climate outcomes.

Erosion risk rises

The latest reading of glacial melt rates suggests that the risk of storm surges for many of the world’s greatest cities will double by the close of the century. But coastal cities – and the farmers who already work 38% of the terrestrial surface to feed almost 8bn people – have another more immediate problem.

In a warmer world, more water evaporates. In a warmer atmosphere, the capacity of the air to hold moisture also increases, so along with more intense droughts, heavier rainfall is on the way for much of the world. And the heavier the rain, or the more prolonged the drought, the higher the risk of soil erosion.

In 2015 the world’s farmers and foresters watched 43 billion tonnes of topsoil wash away from hillsides or blow away from tilled land and into the sea. By 2070, this burden of silt swept away by water or blown by wind will have risen by between 30% and 66%: probably more than 28 bn tons of additional loss.

This could only impoverish the farmland, according to a study by Swiss scientists in the Proceedings of the National Academy of Sciences. It could also impoverish people, communities and countries. The worst hit could be in the less developed nations of the tropics and subtropics.

But the flow of ever-higher silt levels into ever-rising seas also raises a new hazard: hydrologists call it river avulsion. It’s a simple and natural process. As conditions change, so rivers will naturally change their flow to spill over new floodplains and extend coastal lands.

Survival in question

But river avulsions can also be helped along by rising sea levels. Since 10% of humanity is crowded into rich, fertile delta lands, and since some of the deadliest floods in human history – two in China in 1887 and 1931 claimed six million lives – have been caused by river avulsions, the question becomes a matter of life and death.

US scientists report, also in the Proceedings of the National Academy of Sciences, that rising sea levels alone could make abrupt river avulsion more probable, especially as delta lands could be subsiding, because of groundwater and other extraction.

The dangers of avulsion are affected by the rate of sediment deposit in the river channels, and this is likely to rise with sea levels. This in turn raises the level of the river and eventually a breach of a levee or other flood defence will force the river to find a swifter, steeper path to the sea.

Cities such as New Orleans and the coastal communities of the Mississippi delta are already vulnerable. “Avulsions are the earthquakes of rivers,” said Michael Lamb, of California Institute of Technology, one of the authors.

“They are sudden and sometimes catastrophic natural events that occur with statistical regularity, shifting the direction of major rivers. We are trying to understand where and when the next avulsions will occur.” – Climate News Network

Restoring forests can reduce greenhouse gases

In a way, money does grow on trees. So it could pay to help nature restore forests and reduce greenhouse gases.

LONDON, 20 August, 2020 – There is one straightforward way to reduce greenhouse gases: by taking better care of the world’s natural forests.

European and US scientists think they may have settled a complex argument about how to restore a natural forest so that it absorbs more carbon. Don’t just leave nature to regenerate in the way she knows best. Get into the woodland and manage, and plant.

It will cost more money, but it will sequester more carbon: potentially enough to make economic good sense.

Researchers from 13 universities and research institutions report in the journal Science that they carefully mapped and then studied a stretch of tropical forest in Sabah, in Malaysian Borneo: a forest that had been heavily logged more than 30 years ago, and converted to plantation, and then finally protected from further damage. The mapping techniques recorded where, and how much, above-ground carbon was concentrated, across thousands of hectares.

Faster recovery

The researchers report that those reaches of forest left to regenerate without human help recovered by as much as 2.9 tonnes of above-ground carbon per hectare each year. But those areas of forest that were helped a little, by what the scientists call “active restoration”, did even better.

Humans entered the regenerating forests and cut back the lianas – the climbing plants that flourish in degraded forests and compete with saplings – to help seedlings flourish. They also weeded where appropriate and enriched the mix of new plants with native seedlings.

Where this happened, the forest recovered 50% faster and carbon storage above-ground per hectare was measured at between 2.9 tonnes per hectare and 4.4 tonnes.

The lesson to be drawn is that where a natural forest may be thought fully restored after 60 years, active restoration could make it happen in 40 years.

“Restoration helps previously over-used forests not only to recover carbon, but also to become ecologically sound and diverse again”

The research demonstrates two things. The first is that forests can and will restore themselves: opportunistic plants will colonise open space and provide cover for those species best adapted to long-term survival in that climate and habitat. Nature will decide what conservationists call “the climax vegetation” of any natural forest. The second is that nature can indeed benefit from selective human help.

“This active restoration encourages naturally diverse forest, and is therefore much more beneficial for biodiversity than monocultures or plantation forests,” said Christopher Philipson, of the Swiss Federal Technology Institute known as ETH Zurich.

“In this way restoration helps previously over-used forests not only to recover carbon, but also to become ecologically sound and diverse again.”

There will be arguments about the finding. One is that what might be a good solution in south-east Asia might not be the best answer for the Congo or parts of the Amazon: as humans degrade the forest, they may also affect the local climate in ways that favour some native species rather than others. That is, it might never be possible to restore a forest to what it had been before the forester’s axe arrived.

Restoration’s pricetag

There is a second argument: restoration work costs money. How much economic sense it makes depends on what value scientists, politicians and economists put on the carbon that is sequestered as a consequence, and what price humanity pays for that same carbon in the form of additional greenhouse gas that will raise global temperatures, alter rainfall patterns and trigger potentially catastrophic climate change.

What worth do forests have to local populations, and what is the value set on the world’s wildernesses as global natural capital?

“Not long ago we treated degraded tropical forests as lost causes,” said a co-author, Greg Asner of Arizona State University.

“Our new findings, combined with those of other researchers around the world, strongly suggest that restoring tropical forests is a viable and highly scalable solution to regaining lost carbon stocks on land.” – Climate News Network

In a way, money does grow on trees. So it could pay to help nature restore forests and reduce greenhouse gases.

LONDON, 20 August, 2020 – There is one straightforward way to reduce greenhouse gases: by taking better care of the world’s natural forests.

European and US scientists think they may have settled a complex argument about how to restore a natural forest so that it absorbs more carbon. Don’t just leave nature to regenerate in the way she knows best. Get into the woodland and manage, and plant.

It will cost more money, but it will sequester more carbon: potentially enough to make economic good sense.

Researchers from 13 universities and research institutions report in the journal Science that they carefully mapped and then studied a stretch of tropical forest in Sabah, in Malaysian Borneo: a forest that had been heavily logged more than 30 years ago, and converted to plantation, and then finally protected from further damage. The mapping techniques recorded where, and how much, above-ground carbon was concentrated, across thousands of hectares.

Faster recovery

The researchers report that those reaches of forest left to regenerate without human help recovered by as much as 2.9 tonnes of above-ground carbon per hectare each year. But those areas of forest that were helped a little, by what the scientists call “active restoration”, did even better.

Humans entered the regenerating forests and cut back the lianas – the climbing plants that flourish in degraded forests and compete with saplings – to help seedlings flourish. They also weeded where appropriate and enriched the mix of new plants with native seedlings.

Where this happened, the forest recovered 50% faster and carbon storage above-ground per hectare was measured at between 2.9 tonnes per hectare and 4.4 tonnes.

The lesson to be drawn is that where a natural forest may be thought fully restored after 60 years, active restoration could make it happen in 40 years.

“Restoration helps previously over-used forests not only to recover carbon, but also to become ecologically sound and diverse again”

The research demonstrates two things. The first is that forests can and will restore themselves: opportunistic plants will colonise open space and provide cover for those species best adapted to long-term survival in that climate and habitat. Nature will decide what conservationists call “the climax vegetation” of any natural forest. The second is that nature can indeed benefit from selective human help.

“This active restoration encourages naturally diverse forest, and is therefore much more beneficial for biodiversity than monocultures or plantation forests,” said Christopher Philipson, of the Swiss Federal Technology Institute known as ETH Zurich.

“In this way restoration helps previously over-used forests not only to recover carbon, but also to become ecologically sound and diverse again.”

There will be arguments about the finding. One is that what might be a good solution in south-east Asia might not be the best answer for the Congo or parts of the Amazon: as humans degrade the forest, they may also affect the local climate in ways that favour some native species rather than others. That is, it might never be possible to restore a forest to what it had been before the forester’s axe arrived.

Restoration’s pricetag

There is a second argument: restoration work costs money. How much economic sense it makes depends on what value scientists, politicians and economists put on the carbon that is sequestered as a consequence, and what price humanity pays for that same carbon in the form of additional greenhouse gas that will raise global temperatures, alter rainfall patterns and trigger potentially catastrophic climate change.

What worth do forests have to local populations, and what is the value set on the world’s wildernesses as global natural capital?

“Not long ago we treated degraded tropical forests as lost causes,” said a co-author, Greg Asner of Arizona State University.

“Our new findings, combined with those of other researchers around the world, strongly suggest that restoring tropical forests is a viable and highly scalable solution to regaining lost carbon stocks on land.” – Climate News Network

Indian law restores once dried-up rivers to villagers

Indian villagers who brought dried-up rivers back to life then had to fight a legal battle to use their water.

LONDON, 7 August, 2020 – Drought and dried-up rivers can spell catastrophe for rural communities that rely on their crops for survival. But villagers in India have shown that both threats can be reversed and livelihoods restored – with the backing of the law.

Having succeeded in restoring their rivers’ flow, the villagers faced another battle with their local government and vested interests which wanted to take over the new water supply for their own use. So they went to court, formed their own “water parliament”, and wrested back control.

The story began back in 1985 in the parched lands of Rajasthan in north-west India, when villagers were suffering acutely because the rivers they relied on to water their crops were running dry. They resorted to building johads, traditional hand-dug earth dams, which capture water in the rainy season so that it can soak into the earth and be retained instead of flooding away uselessly.

Often called natural flood management, this approach mimics the natural process of rivers which become blocked by debris and trees – with the beneficial results seen in the complex ecosystems created by beavers, which build their own dams and thereby prevent flooding downstream while also storing water for the dry season.

The first dam was built at the original source of the Arvari river, which for the first 45 kilometres of its length had stopped flowing at all. It took 375 earth dams before the Arvari started to flow again, and 10 years before it became a perennial river once more.

“The unsustainable use of water in modern agriculture and the demands made on aquifers by conurbations is already at breaking point in many places around the globe”

Success was infectious. Altogether, over those 10 years, the residents of 1,000 villages built more than 8,600 johads and other structures to collect water for use in the dry seasons. Remarkably, five rivers – the Arvari, Ruparel, Sarsa, Bhagani and Jahajwali – began to flow again, their valleys turning green with crops.

The rivers gained in value again. So the government of Rajasthan, seeing an opportunity to make money, claimed ownership, even awarding fishing licences to contractors, who were stopped by furious local people.

Fortunately the courts sided with the protestors and handed control of the river to them after 72 villages formed what they called the Arvari River Parliament to administer the river and allot rights to water resources in a fair manner.

They were lucky: the Indian constitution allows local people to get financial and legal support in cases against perceived injustices. This meant they had access to justice which they could not otherwise have afforded. The system favours local democracy where it can be shown to work.

Over-exploitation

The Rapid Transition Alliance (RTA) is a UK-based organisation which argues that humankind must undertake “widespread behaviour change to sustainable lifestyles … to live within planetary ecological boundaries and to limit global warming to below 1.5°C” (the more stringent limit set by the 2015 Paris Agreement on climate change).

The story of the success of the earth dams is told by the RTA as part of its series publicising global examples of how projects and communities can combat the environmental destruction caused by the effects of climate heating.

The drying-up of water resources, combined with climate change, is one of the key problems of poor river management in many parts of the world. Climates vary markedly, but on rivers in Africa, Europe and the US vital water resources are also drying up, often through over-exploitation as well as drought.

The Alliance says: “The unsustainable use of water in modern agriculture and the demands made on aquifers by conurbations is already at breaking point in many places around the globe. Climate change is exacerbating this with higher temperatures in already dry places.”

Resisting usurpers

It cites a range of schemes used to tackle the problem, similar in essence to Rajasthan’s diversion of the wet season rains by the johads into underground aquifers rather than letting the water run to waste.

Its message is that solutions need to be low-tech, cheap and achievable by local people acting together democratically to decide what is best for the community. Often this involves resisting local government and big business in their attempts to exploit and profit from the scarce water   frequently the cause of the original damage to the river.

The Alliance says two lessons from Rajasthan translate to other locations and across cultures: first, the physical return of water in a controlled way to an arid environment is possible using low-tech, cheap, accessible solutions.

Second, it says, the guardianship of a natural resource can be achieved effectively by using a communal parliament where all interests are represented equally and fair decisions are taken. – Climate News Network

* * * * * * *

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

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

Indian villagers who brought dried-up rivers back to life then had to fight a legal battle to use their water.

LONDON, 7 August, 2020 – Drought and dried-up rivers can spell catastrophe for rural communities that rely on their crops for survival. But villagers in India have shown that both threats can be reversed and livelihoods restored – with the backing of the law.

Having succeeded in restoring their rivers’ flow, the villagers faced another battle with their local government and vested interests which wanted to take over the new water supply for their own use. So they went to court, formed their own “water parliament”, and wrested back control.

The story began back in 1985 in the parched lands of Rajasthan in north-west India, when villagers were suffering acutely because the rivers they relied on to water their crops were running dry. They resorted to building johads, traditional hand-dug earth dams, which capture water in the rainy season so that it can soak into the earth and be retained instead of flooding away uselessly.

Often called natural flood management, this approach mimics the natural process of rivers which become blocked by debris and trees – with the beneficial results seen in the complex ecosystems created by beavers, which build their own dams and thereby prevent flooding downstream while also storing water for the dry season.

The first dam was built at the original source of the Arvari river, which for the first 45 kilometres of its length had stopped flowing at all. It took 375 earth dams before the Arvari started to flow again, and 10 years before it became a perennial river once more.

“The unsustainable use of water in modern agriculture and the demands made on aquifers by conurbations is already at breaking point in many places around the globe”

Success was infectious. Altogether, over those 10 years, the residents of 1,000 villages built more than 8,600 johads and other structures to collect water for use in the dry seasons. Remarkably, five rivers – the Arvari, Ruparel, Sarsa, Bhagani and Jahajwali – began to flow again, their valleys turning green with crops.

The rivers gained in value again. So the government of Rajasthan, seeing an opportunity to make money, claimed ownership, even awarding fishing licences to contractors, who were stopped by furious local people.

Fortunately the courts sided with the protestors and handed control of the river to them after 72 villages formed what they called the Arvari River Parliament to administer the river and allot rights to water resources in a fair manner.

They were lucky: the Indian constitution allows local people to get financial and legal support in cases against perceived injustices. This meant they had access to justice which they could not otherwise have afforded. The system favours local democracy where it can be shown to work.

Over-exploitation

The Rapid Transition Alliance (RTA) is a UK-based organisation which argues that humankind must undertake “widespread behaviour change to sustainable lifestyles … to live within planetary ecological boundaries and to limit global warming to below 1.5°C” (the more stringent limit set by the 2015 Paris Agreement on climate change).

The story of the success of the earth dams is told by the RTA as part of its series publicising global examples of how projects and communities can combat the environmental destruction caused by the effects of climate heating.

The drying-up of water resources, combined with climate change, is one of the key problems of poor river management in many parts of the world. Climates vary markedly, but on rivers in Africa, Europe and the US vital water resources are also drying up, often through over-exploitation as well as drought.

The Alliance says: “The unsustainable use of water in modern agriculture and the demands made on aquifers by conurbations is already at breaking point in many places around the globe. Climate change is exacerbating this with higher temperatures in already dry places.”

Resisting usurpers

It cites a range of schemes used to tackle the problem, similar in essence to Rajasthan’s diversion of the wet season rains by the johads into underground aquifers rather than letting the water run to waste.

Its message is that solutions need to be low-tech, cheap and achievable by local people acting together democratically to decide what is best for the community. Often this involves resisting local government and big business in their attempts to exploit and profit from the scarce water   frequently the cause of the original damage to the river.

The Alliance says two lessons from Rajasthan translate to other locations and across cultures: first, the physical return of water in a controlled way to an arid environment is possible using low-tech, cheap, accessible solutions.

Second, it says, the guardianship of a natural resource can be achieved effectively by using a communal parliament where all interests are represented equally and fair decisions are taken. – Climate News Network

* * * * * * *

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

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