Category Archives: Nature

Halve the farmland, save nature, feed the world

This story is a part of Covering Climate Now’s week of coverage focused on Climate Solutions, to mark the 50th anniversary of Earth Day. Covering Climate Now is a global journalism collaboration committed to strengthening coverage of the climate story.

If we farm efficiently, scientists say, we can cut climate change, slow extinction and feed the world even as it asks for more.

LONDON, 21 April, 2020 – Forget about organic farming: get the best out of the best cropland, return the rest to nature and still feed the world. It could work, say researchers.

Once again, scientists have demonstrated that humans could restore roughly half the planet as a natural home for all the other wild things, while at the same time feeding a growing population and limiting climate change.

That doesn’t mean it will happen, or could be made to happen easily. But it does yet again address one of the enduring challenges of population growth and the potentially devastating loss of the biodiversity upon which all individual species – humans more than most – depend to survive.

The answer? Simply to farm more efficiently and more intensively, to maximise the yield from those tracts of land most suitable for crops, and let nature reclaim the no-longer so productive hectares.

Even more effective would be to release as much land as possible in those regions that ecologists and biologists like to call “biodiversity hotspots”, among them the forests where concentrations of species are at their peak.

European researchers argue, in a study in the journal Nature Sustainability, that as less land was cultivated, but more intensively, the greenhouse gas emissions from farming would be reduced: so too would water use.

“Cropland expansion is not inevitable and there is significant potential for improving present land use efficiency”

“The main questions we wanted to address were how much cropland could be spared if attainable crop yields were achieved globally and crops were grown where they are most productive,” said Christian Folberth, a scientist with the International Institute for Applied Systems Analysis (IIASA) in Austria, who led the study.

“In addition, we wanted to determine what the implications would be for other factors related to the agricultural sector, including fertiliser and irrigation water requirements, greenhouse gas emissions, carbon sequestration potential, and wildlife habitat for threatened species.”

The problem is enormous, and enormously complex. Cropland farming alone – forget about methane from cattle and sheep – accounts for 5% of all greenhouse gas emissions from human activity. Worldwide, about 70% of all the freshwater taken from rivers and aquifers goes into irrigation.

Human populations continue to soar, while cities continue to expand  across the countryside. By the end of this century, there could be more than 9bn people to be fed.

Global heating driven by fossil fuel investment continues to increase, and this in turn threatens to diminish harvest yields across a wide range of crops, along with the nutritive value of the staples themselves.

Nature under threat

At the same time, both climate change driven by global warming and the expansion of the cities and the surrounding farmlands continue to amplify the threat to natural habitats and the millions of species – many yet to be identified and named by science – that depend upon them.

And this in turn poses a threat to human economies and even human life: almost every resource – antibiotic medicines and drugs, food, waste disposal, fabrics, building materials and even fresh air and water – evolved in undisturbed ecosystems long before Homo sapiens arrived, and the services each element provides depend ultimately on the survival of those ecosystems.

So the challenge is to restore and return to nature around half the land humans already use, while at the same time feeding what could be an additional 2bn people, while reducing greenhouse gas emissions but still sustaining development in the poorest nations.

Dr Folberth and his colleagues from Slovakia, France, Belgium, Spain and the UK are not the first to argue that it can be done, and not just by changing the planetary lunch menu.

The scientists looked at the data for 16 major crop species around the world to calculate that at least in theory – with careful use of the right crops on the most suitable soils, and with high fertiliser use – about half of the present cropland now cultivated could still deliver the present output.

That is, the land humans occupy is not being managed efficiently. If it were, the other half could be returned to wilderness, and conserved as natural forest, grassland or wetland.

Climate benefits

If humans then thought about how best to slow biodiversity loss, they would do almost as well by abandoning farmland in those places where there was the greatest concentration of wild things – tropical rain forests, estuary floodplains and mangrove swamps, for instance. And just returning 20% of farmland to nature everywhere else would still reduce human farmland use by 40%.

In return, fertiliser use would remain about the same, but greenhouse gas emissions and water use would fall, while more land would become free to sequester atmospheric carbon.

There would be costs – nitrogen pollution would go up in some places, and many rural farmers would become even poorer – so more thinking needs to be done. The point the European researchers want to make is that, in principle, it should be possible to feed people, abandon farmland to the natural world and reduce emissions all at the same time.

“It shows that cropland expansion is not inevitable and there is significant potential for improving present land use efficiency,” said Michael Obersteiner, another author, now at the Environmental Change Institute at Oxford.

“If the right policies are implemented, measures such as improved production technologies can be just as effective as demand-side measures like dietary changes. However, in all cases, such a process would need to be steered by policies to avoid unwanted outcomes.” – Climate News Network

This story is a part of Covering Climate Now’s week of coverage focused on Climate Solutions, to mark the 50th anniversary of Earth Day. Covering Climate Now is a global journalism collaboration committed to strengthening coverage of the climate story.

If we farm efficiently, scientists say, we can cut climate change, slow extinction and feed the world even as it asks for more.

LONDON, 21 April, 2020 – Forget about organic farming: get the best out of the best cropland, return the rest to nature and still feed the world. It could work, say researchers.

Once again, scientists have demonstrated that humans could restore roughly half the planet as a natural home for all the other wild things, while at the same time feeding a growing population and limiting climate change.

That doesn’t mean it will happen, or could be made to happen easily. But it does yet again address one of the enduring challenges of population growth and the potentially devastating loss of the biodiversity upon which all individual species – humans more than most – depend to survive.

The answer? Simply to farm more efficiently and more intensively, to maximise the yield from those tracts of land most suitable for crops, and let nature reclaim the no-longer so productive hectares.

Even more effective would be to release as much land as possible in those regions that ecologists and biologists like to call “biodiversity hotspots”, among them the forests where concentrations of species are at their peak.

European researchers argue, in a study in the journal Nature Sustainability, that as less land was cultivated, but more intensively, the greenhouse gas emissions from farming would be reduced: so too would water use.

“Cropland expansion is not inevitable and there is significant potential for improving present land use efficiency”

“The main questions we wanted to address were how much cropland could be spared if attainable crop yields were achieved globally and crops were grown where they are most productive,” said Christian Folberth, a scientist with the International Institute for Applied Systems Analysis (IIASA) in Austria, who led the study.

“In addition, we wanted to determine what the implications would be for other factors related to the agricultural sector, including fertiliser and irrigation water requirements, greenhouse gas emissions, carbon sequestration potential, and wildlife habitat for threatened species.”

The problem is enormous, and enormously complex. Cropland farming alone – forget about methane from cattle and sheep – accounts for 5% of all greenhouse gas emissions from human activity. Worldwide, about 70% of all the freshwater taken from rivers and aquifers goes into irrigation.

Human populations continue to soar, while cities continue to expand  across the countryside. By the end of this century, there could be more than 9bn people to be fed.

Global heating driven by fossil fuel investment continues to increase, and this in turn threatens to diminish harvest yields across a wide range of crops, along with the nutritive value of the staples themselves.

Nature under threat

At the same time, both climate change driven by global warming and the expansion of the cities and the surrounding farmlands continue to amplify the threat to natural habitats and the millions of species – many yet to be identified and named by science – that depend upon them.

And this in turn poses a threat to human economies and even human life: almost every resource – antibiotic medicines and drugs, food, waste disposal, fabrics, building materials and even fresh air and water – evolved in undisturbed ecosystems long before Homo sapiens arrived, and the services each element provides depend ultimately on the survival of those ecosystems.

So the challenge is to restore and return to nature around half the land humans already use, while at the same time feeding what could be an additional 2bn people, while reducing greenhouse gas emissions but still sustaining development in the poorest nations.

Dr Folberth and his colleagues from Slovakia, France, Belgium, Spain and the UK are not the first to argue that it can be done, and not just by changing the planetary lunch menu.

The scientists looked at the data for 16 major crop species around the world to calculate that at least in theory – with careful use of the right crops on the most suitable soils, and with high fertiliser use – about half of the present cropland now cultivated could still deliver the present output.

That is, the land humans occupy is not being managed efficiently. If it were, the other half could be returned to wilderness, and conserved as natural forest, grassland or wetland.

Climate benefits

If humans then thought about how best to slow biodiversity loss, they would do almost as well by abandoning farmland in those places where there was the greatest concentration of wild things – tropical rain forests, estuary floodplains and mangrove swamps, for instance. And just returning 20% of farmland to nature everywhere else would still reduce human farmland use by 40%.

In return, fertiliser use would remain about the same, but greenhouse gas emissions and water use would fall, while more land would become free to sequester atmospheric carbon.

There would be costs – nitrogen pollution would go up in some places, and many rural farmers would become even poorer – so more thinking needs to be done. The point the European researchers want to make is that, in principle, it should be possible to feed people, abandon farmland to the natural world and reduce emissions all at the same time.

“It shows that cropland expansion is not inevitable and there is significant potential for improving present land use efficiency,” said Michael Obersteiner, another author, now at the Environmental Change Institute at Oxford.

“If the right policies are implemented, measures such as improved production technologies can be just as effective as demand-side measures like dietary changes. However, in all cases, such a process would need to be steered by policies to avoid unwanted outcomes.” – Climate News Network

Tree rings and weather data warn of megadrought

Farmers in the US West know they have a drought, but may not yet realise these arid years could become a megadrought.

LONDON, 17 April, 2020 – Climate change could be pushing the US west and northern Mexico towards the most severe and most extended period of drought observed in a thousand years of US history, a full-blown megadrought.

Natural atmospheric forces have always triggered prolonged spells with little rain. But warming driven by profligate human use of fossil fuels could now be making a bad situation much worse.

The warning of what climate scientists call a megadrought – outlined in the journal Science – is based not on computer simulations but on direct testimony from more than a century of weather records and the much longer story told by 1200 consecutive years of evidence preserved in the annual growth rings of trees that provide a record of changing levels of soil moisture.

“Earlier studies were largely model projections of the future. We are no longer looking at projections, but at where we are now,” said Park Williams, a bioclimatologist at the Lamont Doherty Earth Observatory of Columbia University in the US.

“We now have enough observations of current drought and tree ring records of past drought to say we’re on the same trajectory as the worst prehistoric droughts.”

Repeating the past

Previous research has already linked catastrophic drought to turmoil among pre-Columbian civilisations in the American Southwest.

Studies by other groups have also warned that what happened in the past could happen again, as carbon dioxide emissions from fossil fuel combustion enrich the atmosphere, raise temperatures and parch the soils of the US West.

Global heating has been repeatedly linked to the last devastating drought in California, and to the possible return of Dust Bowl conditions in the Midwestern grain belt.

The latest study delivers a long-term analysis of conditions across nine US states, from Oregon and Montana in the north down to California, New Mexico and part of northern Mexico.

With the evidence preserved in old tree trunks, the scientists identified dozens of droughts in the region from 800 AD. They found four megadroughts – periods in which the conditions became extreme – between 800 and 1600. Since then there have been no droughts that could be matched with these – so far.

And then the researchers matched the megadrought tree ring evidence with soil moisture records collected in the first 19 years of this century, and compared this with any 19-year period in the prehistoric droughts.

“We’ll need more and more good luck to break out of drought, and less and less bad luck to get into drought”

They found that the current prolonged dry spell is already more pronounced than the three earliest records of megadrought. The fourth megadrought – it ran from 1575 to 1603 – may still have been the worst of all, but the match with the present years is so close that nobody can be sure.

But the team behind the Science study is sure of one thing. This drought right now is affecting wider stretches of landscape more consistently than any of the earlier megadroughts, and this, they say, is a signature of global heating. All the ancient megadroughts lasted longer, and sometimes much longer, than 19 years, but all began in a way very similar to the present.

The snowpack in the western high mountains has fallen dramatically, the flow of the rivers has dwindled, lake levels have fallen, farmers have been  hit and the wildfires have become more prolonged and more intense.

Drought and even the chance of megadrought may be a fact of life in the US West. During occasional natural atmospheric cycles, the tropical Pacific cools and storm tracks shift further north, taking rainfall away from the US drylands.

But since 2000, average air temperatures in the western states have risen by more than 1.2°C above the normal over earlier centuries. So soils already starved of rain began to lose their stored moisture at an ever-increasing rate.

Worsened by heating

Without the additional global heating, this drought might have happened anyway, and perhaps even been the 11th worst ever recorded, rather than almost the worst ever in human experience.

“It doesn’t matter if this is exactly the worst drought ever,” said Benjamin Cook, a co-author, from Nasa’s Goddard Institute for Space Studies. “What matters is that it has been made much worse than it could have been because of climate change.”

The researchers also found that the 20th century was the wettest century in the entire 1200 year record, and this relatively plentiful supply of water must have helped enrich the US West and make California, for instance, become the Golden State, the most populous in the US.

“Because the background is getting warmer, the dice are increasingly loaded towards longer and more severe droughts,” Professor Williams said. “We may get lucky, and natural variability will bring more precipitation for a while.

“But going forward, we’ll need more and more good luck to break out of drought, and less and less bad luck to get into drought.” – Climate News Network

Farmers in the US West know they have a drought, but may not yet realise these arid years could become a megadrought.

LONDON, 17 April, 2020 – Climate change could be pushing the US west and northern Mexico towards the most severe and most extended period of drought observed in a thousand years of US history, a full-blown megadrought.

Natural atmospheric forces have always triggered prolonged spells with little rain. But warming driven by profligate human use of fossil fuels could now be making a bad situation much worse.

The warning of what climate scientists call a megadrought – outlined in the journal Science – is based not on computer simulations but on direct testimony from more than a century of weather records and the much longer story told by 1200 consecutive years of evidence preserved in the annual growth rings of trees that provide a record of changing levels of soil moisture.

“Earlier studies were largely model projections of the future. We are no longer looking at projections, but at where we are now,” said Park Williams, a bioclimatologist at the Lamont Doherty Earth Observatory of Columbia University in the US.

“We now have enough observations of current drought and tree ring records of past drought to say we’re on the same trajectory as the worst prehistoric droughts.”

Repeating the past

Previous research has already linked catastrophic drought to turmoil among pre-Columbian civilisations in the American Southwest.

Studies by other groups have also warned that what happened in the past could happen again, as carbon dioxide emissions from fossil fuel combustion enrich the atmosphere, raise temperatures and parch the soils of the US West.

Global heating has been repeatedly linked to the last devastating drought in California, and to the possible return of Dust Bowl conditions in the Midwestern grain belt.

The latest study delivers a long-term analysis of conditions across nine US states, from Oregon and Montana in the north down to California, New Mexico and part of northern Mexico.

With the evidence preserved in old tree trunks, the scientists identified dozens of droughts in the region from 800 AD. They found four megadroughts – periods in which the conditions became extreme – between 800 and 1600. Since then there have been no droughts that could be matched with these – so far.

And then the researchers matched the megadrought tree ring evidence with soil moisture records collected in the first 19 years of this century, and compared this with any 19-year period in the prehistoric droughts.

“We’ll need more and more good luck to break out of drought, and less and less bad luck to get into drought”

They found that the current prolonged dry spell is already more pronounced than the three earliest records of megadrought. The fourth megadrought – it ran from 1575 to 1603 – may still have been the worst of all, but the match with the present years is so close that nobody can be sure.

But the team behind the Science study is sure of one thing. This drought right now is affecting wider stretches of landscape more consistently than any of the earlier megadroughts, and this, they say, is a signature of global heating. All the ancient megadroughts lasted longer, and sometimes much longer, than 19 years, but all began in a way very similar to the present.

The snowpack in the western high mountains has fallen dramatically, the flow of the rivers has dwindled, lake levels have fallen, farmers have been  hit and the wildfires have become more prolonged and more intense.

Drought and even the chance of megadrought may be a fact of life in the US West. During occasional natural atmospheric cycles, the tropical Pacific cools and storm tracks shift further north, taking rainfall away from the US drylands.

But since 2000, average air temperatures in the western states have risen by more than 1.2°C above the normal over earlier centuries. So soils already starved of rain began to lose their stored moisture at an ever-increasing rate.

Worsened by heating

Without the additional global heating, this drought might have happened anyway, and perhaps even been the 11th worst ever recorded, rather than almost the worst ever in human experience.

“It doesn’t matter if this is exactly the worst drought ever,” said Benjamin Cook, a co-author, from Nasa’s Goddard Institute for Space Studies. “What matters is that it has been made much worse than it could have been because of climate change.”

The researchers also found that the 20th century was the wettest century in the entire 1200 year record, and this relatively plentiful supply of water must have helped enrich the US West and make California, for instance, become the Golden State, the most populous in the US.

“Because the background is getting warmer, the dice are increasingly loaded towards longer and more severe droughts,” Professor Williams said. “We may get lucky, and natural variability will bring more precipitation for a while.

“But going forward, we’ll need more and more good luck to break out of drought, and less and less bad luck to get into drought.” – Climate News Network

Entire wild systems at risk from rising global heat

Rising global heat raises risks to the creatures and ecosystems that sustain human society. Collapse could be sudden and near-total.

LONDON, 14 April, 2020 – Worldwide, entire ecosystems could collapse as the planetary thermometer soars: rising global heat could see the Earth’s average temperature rise by 4°C (right now the world is heading for a rise of more than three degrees).

And then one in six of the complex communities of plants and animals in wetlands, grasslands, forests or oceans could drastically alter or fail.

That is because at such temperatures more than one in five of the creatures in that network of co-dependencies would in the same decade experience temperatures beyond their normal tolerance levels.

The prediction is based on data that pinpoint the geographical ranges of 30,652 birds, mammals, reptiles, amphibians, fish and plants, and climate data from 1850 to 2005.

“We found that climate change risks to biodiversity don’t increase gradually,” said Alex Pigot of Imperial College London, in the UK, who led the research.

Abrupt change

“Instead, as the climate warms, within a certain area most species will be able to cope for a while, before crossing a temperature threshold, when a large proportion of the species will suddenly face conditions they’ve never experienced before.

“It’s not a slippery slope, but a series of cliff edges, hitting different areas at different times.”

The finding – published in the journal Nature – should come as no great surprise to the world’s zoologists, botanists, ecologists, foresters, marine scientists and conservationists.

They have repeatedly warned that as global temperatures rise, and climate patterns become increasingly unstable, in response to ever-higher greenhouse gas emissions from power stations and car exhausts, and forest destruction, both individual species and even whole habitats could be exposed to loss and species extinction.

Such threats can be prefigured even in subtle changes in species behaviour. Within this month, Spanish ornithologists who have studied the nightingale Luscinia megarhynchos since 1995 report in the journal The Auk: Ornithological Advances that in two decades, as Spanish summers became hotter and more parched, the wings of each new generation of birds have become progressively shorter.

“Our findings highlight the urgent need for climate change mitigation, by immediately and drastically reducing emissions, which could help save thousands of species from extinction”

A shorter wingspan in proportion to body length creates potential survival problems for a species that breeds in Europe but prefers to fly to sub-Saharan Africa for the winter.

And across the Atlantic, another species, the American robin Turdus migratorius now takes wing 12 days earlier each spring in Mexico and the US to fly to its summer breeding grounds in Canada and Alaska.

The ornithologists report in the journal Environmental Research Letters that GPS tracking of 55 individual birds confirms that the bird may be timing its migration to the snow melt and the first arrival of insects in the high latitudes nearer the fast-warming Arctic.

So far, the planet on average has warmed around only 1°C above the long-term average for most of human history. But Dr Pigot and colleagues in the US and South Africa wanted to look at the big picture of potential change in species everywhere as global heating reaches 2°C – the upper limits that the world’s nations promised in a key international agreement reached in Paris in 2015 – and then goes on soaring.

So they took their species data, and mapped it onto a global grid divided into 100-km-square cells, and then fine-tuned the temperature predicted by climate scientists to see where species and their habitats would experience ever-rising heat beyond their comfort zone.

Unprecedented ocean heat

Any ecosystem is a network of interdependencies: insects pollinate flowers, animals disperse seed and prey upon pests and each other in an intricate set of arrangements that have evolved over tens of thousands of years in a particular pattern of temperature and precipitation. Any disturbance ripples through the entire habitat.

The scientists’ atlas of potential ecological disruption included isolated bits of the world such as the Cayman Islands in the Caribbean and the Gobi Desert in Mongolia as well as the Amazon basin and the forests and clearings in the Congo, and one of the world’s richest marine habitats, the so-called Coral Triangle bounded by the Philippines, Malaysia, Papua New Guinea and the islands of the Western Pacific.

They found that if warming could be contained to 2°C or less, only about one community in 50 would be faced with exposure to such disruption: they warn however that even this 2% includes some of the richest habitats on the planet.

They also warn that by 2030, the tropical oceans will start to experience temperature regimes that have no precedent in human history. The tropical forests could be at risk by 2050. Ominously, almost three-fourths of all the species to face unprecedented temperatures before the end of this century will all do so more or less at the same time.

“Our findings highlight the urgent need for climate change mitigation, by immediately and drastically reducing emissions, which could help save thousands of species from extinction,” Dr Pigot said. – Climate News Network

Rising global heat raises risks to the creatures and ecosystems that sustain human society. Collapse could be sudden and near-total.

LONDON, 14 April, 2020 – Worldwide, entire ecosystems could collapse as the planetary thermometer soars: rising global heat could see the Earth’s average temperature rise by 4°C (right now the world is heading for a rise of more than three degrees).

And then one in six of the complex communities of plants and animals in wetlands, grasslands, forests or oceans could drastically alter or fail.

That is because at such temperatures more than one in five of the creatures in that network of co-dependencies would in the same decade experience temperatures beyond their normal tolerance levels.

The prediction is based on data that pinpoint the geographical ranges of 30,652 birds, mammals, reptiles, amphibians, fish and plants, and climate data from 1850 to 2005.

“We found that climate change risks to biodiversity don’t increase gradually,” said Alex Pigot of Imperial College London, in the UK, who led the research.

Abrupt change

“Instead, as the climate warms, within a certain area most species will be able to cope for a while, before crossing a temperature threshold, when a large proportion of the species will suddenly face conditions they’ve never experienced before.

“It’s not a slippery slope, but a series of cliff edges, hitting different areas at different times.”

The finding – published in the journal Nature – should come as no great surprise to the world’s zoologists, botanists, ecologists, foresters, marine scientists and conservationists.

They have repeatedly warned that as global temperatures rise, and climate patterns become increasingly unstable, in response to ever-higher greenhouse gas emissions from power stations and car exhausts, and forest destruction, both individual species and even whole habitats could be exposed to loss and species extinction.

Such threats can be prefigured even in subtle changes in species behaviour. Within this month, Spanish ornithologists who have studied the nightingale Luscinia megarhynchos since 1995 report in the journal The Auk: Ornithological Advances that in two decades, as Spanish summers became hotter and more parched, the wings of each new generation of birds have become progressively shorter.

“Our findings highlight the urgent need for climate change mitigation, by immediately and drastically reducing emissions, which could help save thousands of species from extinction”

A shorter wingspan in proportion to body length creates potential survival problems for a species that breeds in Europe but prefers to fly to sub-Saharan Africa for the winter.

And across the Atlantic, another species, the American robin Turdus migratorius now takes wing 12 days earlier each spring in Mexico and the US to fly to its summer breeding grounds in Canada and Alaska.

The ornithologists report in the journal Environmental Research Letters that GPS tracking of 55 individual birds confirms that the bird may be timing its migration to the snow melt and the first arrival of insects in the high latitudes nearer the fast-warming Arctic.

So far, the planet on average has warmed around only 1°C above the long-term average for most of human history. But Dr Pigot and colleagues in the US and South Africa wanted to look at the big picture of potential change in species everywhere as global heating reaches 2°C – the upper limits that the world’s nations promised in a key international agreement reached in Paris in 2015 – and then goes on soaring.

So they took their species data, and mapped it onto a global grid divided into 100-km-square cells, and then fine-tuned the temperature predicted by climate scientists to see where species and their habitats would experience ever-rising heat beyond their comfort zone.

Unprecedented ocean heat

Any ecosystem is a network of interdependencies: insects pollinate flowers, animals disperse seed and prey upon pests and each other in an intricate set of arrangements that have evolved over tens of thousands of years in a particular pattern of temperature and precipitation. Any disturbance ripples through the entire habitat.

The scientists’ atlas of potential ecological disruption included isolated bits of the world such as the Cayman Islands in the Caribbean and the Gobi Desert in Mongolia as well as the Amazon basin and the forests and clearings in the Congo, and one of the world’s richest marine habitats, the so-called Coral Triangle bounded by the Philippines, Malaysia, Papua New Guinea and the islands of the Western Pacific.

They found that if warming could be contained to 2°C or less, only about one community in 50 would be faced with exposure to such disruption: they warn however that even this 2% includes some of the richest habitats on the planet.

They also warn that by 2030, the tropical oceans will start to experience temperature regimes that have no precedent in human history. The tropical forests could be at risk by 2050. Ominously, almost three-fourths of all the species to face unprecedented temperatures before the end of this century will all do so more or less at the same time.

“Our findings highlight the urgent need for climate change mitigation, by immediately and drastically reducing emissions, which could help save thousands of species from extinction,” Dr Pigot said. – Climate News Network

Poles attract marine life avoiding rising heat

In a warming ocean, some species will swim, others sink. But all agree: the poles attract marine life without exception.

LONDON, 3 April, 2020 − It’s the same the whole world over: everywhere in the oceans of this warming planet, the poles attract marine life.

Molluscs are on the move, haddock are feeling the heat, and penguins are shifting further south. Nautilus are heading north, and plankton are edging towards both poles.

New analysis of marine species has confirmed what commercial fishermen already know to their cost: that as the oceans warm, the sea’s citizens shift their grounds.

Researchers report in the journal Current Biology that they surveyed the evidence assembled in 540 records of 304 widely distributed marine animals over the last century, to find that all of them are shifting their range: away from the equatorial waters, and in both hemispheres nearer to the poles.

In the past century, overall, the world’s oceans have warmed by around 1°C. By 2050, the rise may reach 1.5°C, and all the evidence so far suggests fish and shellfish, along with the microbial creatures at the bottom of the food chain and the marine mammals and seabirds that prey on them all, will have shifted their latitudinal range.

“Both increasing and decreasing abundances may have harmful knock-on effects for the wider ecosystem”

The greatest abundance of any species, the researchers found, was likely to be at the poleward edge of the preferred range, and the sparsest nearest to the tropical waters.

“The main surprise is how pervasive the effects were. We found the same trend across all groups of marine life we looked at, from plankton to marine invertebrates, and from fish to seabirds,” said Martin Genner, an evolutionary ecologist at the University of Bristol in the UK.

“This matters because it means that climate change is not only leading abundance changes, but intrinsically affecting the performance of species locally. We see species such as the Emperor penguin becoming less abundant as the water becomes too warm at their equatorward edge, and we see some fish such as the European sea bass thriving at their poleward edge, where historically they were uncommon.”

Fish and many marine animals have a preferred range of temperatures, and even seemingly imperceptible shifts can have unpredictable effects. Both individual research and commercial catch data have confirmed a series of shifts in response to global heating.

Winners and losers

Tropical fish are shifting away from the hottest waters, North Sea catches are more likely to be found in north Atlantic waters, and some Mediterranean species have now shifted to the waters of Western Europe.

The latest research suggests that whole ecosystems may be on the move, and with them Atlantic herring and Adelie penguins, loggerhead turtles and phytoplankton.

“Some marine species appear to benefit from climate change, particularly some populations at the poleward limits that are now able to thrive,” said Louise Rutterford, another of the research team at Bristol.

“Meanwhile, some marine life suffers as it is not able to adapt fast enough to survive warming, and this is most noticeable in populations nearer the equator.

“This is concerning, as both increasing and decreasing abundances may have harmful knock-on effects for the wider ecosystem.” − Climate News Network

In a warming ocean, some species will swim, others sink. But all agree: the poles attract marine life without exception.

LONDON, 3 April, 2020 − It’s the same the whole world over: everywhere in the oceans of this warming planet, the poles attract marine life.

Molluscs are on the move, haddock are feeling the heat, and penguins are shifting further south. Nautilus are heading north, and plankton are edging towards both poles.

New analysis of marine species has confirmed what commercial fishermen already know to their cost: that as the oceans warm, the sea’s citizens shift their grounds.

Researchers report in the journal Current Biology that they surveyed the evidence assembled in 540 records of 304 widely distributed marine animals over the last century, to find that all of them are shifting their range: away from the equatorial waters, and in both hemispheres nearer to the poles.

In the past century, overall, the world’s oceans have warmed by around 1°C. By 2050, the rise may reach 1.5°C, and all the evidence so far suggests fish and shellfish, along with the microbial creatures at the bottom of the food chain and the marine mammals and seabirds that prey on them all, will have shifted their latitudinal range.

“Both increasing and decreasing abundances may have harmful knock-on effects for the wider ecosystem”

The greatest abundance of any species, the researchers found, was likely to be at the poleward edge of the preferred range, and the sparsest nearest to the tropical waters.

“The main surprise is how pervasive the effects were. We found the same trend across all groups of marine life we looked at, from plankton to marine invertebrates, and from fish to seabirds,” said Martin Genner, an evolutionary ecologist at the University of Bristol in the UK.

“This matters because it means that climate change is not only leading abundance changes, but intrinsically affecting the performance of species locally. We see species such as the Emperor penguin becoming less abundant as the water becomes too warm at their equatorward edge, and we see some fish such as the European sea bass thriving at their poleward edge, where historically they were uncommon.”

Fish and many marine animals have a preferred range of temperatures, and even seemingly imperceptible shifts can have unpredictable effects. Both individual research and commercial catch data have confirmed a series of shifts in response to global heating.

Winners and losers

Tropical fish are shifting away from the hottest waters, North Sea catches are more likely to be found in north Atlantic waters, and some Mediterranean species have now shifted to the waters of Western Europe.

The latest research suggests that whole ecosystems may be on the move, and with them Atlantic herring and Adelie penguins, loggerhead turtles and phytoplankton.

“Some marine species appear to benefit from climate change, particularly some populations at the poleward limits that are now able to thrive,” said Louise Rutterford, another of the research team at Bristol.

“Meanwhile, some marine life suffers as it is not able to adapt fast enough to survive warming, and this is most noticeable in populations nearer the equator.

“This is concerning, as both increasing and decreasing abundances may have harmful knock-on effects for the wider ecosystem.” − Climate News Network

Vegetation holds key to climate control

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

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

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

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

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

Reducing heating

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

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

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

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

Risk to trees

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

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

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

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

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

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

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

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

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

Drying wetlands

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

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

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

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

The Arctic greens

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

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

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

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

Climate feedback

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

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

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

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

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

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

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

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

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

Reducing heating

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

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

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

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

Risk to trees

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

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

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

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

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

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

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

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

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

Drying wetlands

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

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

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

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

The Arctic greens

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

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

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

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

Climate feedback

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

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

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

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

Rainforest and reef systems face collapse

rainforest

In less than a human lifetime, the world’s greatest rainforest could become parched grassland and scrub, and the Caribbean coral reef system could collapse completely.

LONDON, 17 March, 2020 – The entire Amazon rainforest could collapse into savannah – dry grassland with scrub and intermittent woodland – within 50 years as a result of human action.

And the study of what it takes to alter an enduring natural ecosystem confirms that, within as little as 15 years, the rich Caribbean coral reef system could be no more.

A new statistical examination of the vulnerability of what had once seemed the eternal forest and the glorious coral reefs confirms that once large ecosystems begin to change, they can reach a point at which the collapse becomes sudden and irreversible.

The research confirms an increasing fear that global heating driven by profligate human use of fossil fuels could tip not just climate but also natural landscapes into a new and potentially catastrophic states.

Dramatic warning

More directly, as reported in an interview with Brazilian scientist Antonio Donato Nobre in Climate News Network yesterday, it confirms a dramatic warning delivered in December last year that the Amazon rainforest – a landscape almost as vast as the entire 48 contiguous states of the US – may already be teetering on the edge of functional disruption.

How this disruption could happen was recently outlined by two scientists, Thomas Lovejoy, professor of biology at George Mason University in Virginia, US, and Carlos Nobre, a leading expert on the Amazon and climate change, who is the brother of Antonio Donato Nobre and is senior researcher at the University of Saõ Paulo’s Institute for Advanced Studies.

Lovejoy and Carlos Nobre point out that most of the rain that keeps the Amazon a rainforest is actually recycled from the dense canopy that covers the region. After rainfall, evapotranspiration from the foliage returns water vapour to the air above the forest and falls anew as rain, again and again.

“Over the whole basin, the air rises, cools and precipitates out close to 20% of the world’s river water in the Amazon river system,” they warn in a Science journal report.

“Current deforestation is substantial and frightening: 17% across the entire Amazon basin and approaching 20% in the Brazilian Amazon.

“Already there are ominous signals of it in nature. Dry seasons in the Amazon are already hotter and longer. Mortality rates of wet-climate species are increased, whereas dry-climate species are showing resilience. The increasing frequency of unprecedented droughts in 2005, 2010 and 2015/16 is signalling that the tipping point is at hand.”

By contrast, the latest study in Nature Communications zeroes in on the rates at which large ecosystems could, in principle, change once the climate has begun to shift and the natural habitat is in some way degraded.

“This is yet another strong argument to avoid degrading our planet’s ecosystems; we need to do more to conserve biodiversity.”

Three scientists in the UK used computer models to test data from four terrestrial landscapes, 25 marine habitats and 13 freshwater ecosystems. They found, not surprisingly, that larger ecosystems tend to undergo regime shifts more slowly than the smaller ones.

However, as the ecosystem gets bigger, the additional time taken for collapse to happen gets briefer, so big ecosystems fail relatively more quickly.

This would mean that it would take 15 years for 20,000 sq km of Caribbean reef system to collapse, once some fatal trigger point had been reached. And the 5.5 million sq km of the Amazon tropical moist forest, once it starts to go, could be gone in just 49 years.

“Unfortunately, what our paper reveals is that humanity needs to prepare for change far sooner than expected,” says Simon Willcock, senior lecturer in environmental geography at Bangor University in Wales.

And his colleague, Dr Gregory Cooper, postdoctoral research fellow at the University of London’s Centre for Development, Environment and Policy, says: “This is yet another strong argument to avoid degrading our planet’s ecosystems; we need to do more to conserve biodiversity.”

Atmospheric carbon

Other researchers have separately found that the Amazon rainforest could be about to become a source of yet more atmospheric carbon – rather than a green machine for absorbing surplus carbon dioxide from the atmosphere – as a result of climate change and environmental destruction.

The Amazon ecosystem took 58 million years to evolve. But the message is that it could unravel in a very short time.

Alexandre Antonelli, director of science at the Royal Botanic Gardens at Kew, London, was not one of the researchers, but he describes the results of the study as “terrifying” and warns that the Amazon could pass the point of no return this year.

He says: “Nature is fragile. Just because an area is big or a species is common, it doesn’t mean they’ll last forever.

“The Sahel – an area south of the Sahara that is six times the size of Spain – went from being vegetated and bountiful to just a desert in a few hundred years.

“The American chestnut – one of the most important trees of eastern North America – almost faced extinction after a fungal disease caused some three to four billion trees to die in the early 1900s.

“Natural ecosystems are usually resilient to change when kept intact, but after decades of disruption, exploitation and climatic stress, it should come as no surprise that they are breaking down.

“In other words, you can’t simply remove huge chunks of a rainforest and hope everything will be fine – it won’t. Based on these results, 2020 is our very last opportunity to stop Amazonian deforestation.” – Climate News Network

In less than a human lifetime, the world’s greatest rainforest could become parched grassland and scrub, and the Caribbean coral reef system could collapse completely.

LONDON, 17 March, 2020 – The entire Amazon rainforest could collapse into savannah – dry grassland with scrub and intermittent woodland – within 50 years as a result of human action.

And the study of what it takes to alter an enduring natural ecosystem confirms that, within as little as 15 years, the rich Caribbean coral reef system could be no more.

A new statistical examination of the vulnerability of what had once seemed the eternal forest and the glorious coral reefs confirms that once large ecosystems begin to change, they can reach a point at which the collapse becomes sudden and irreversible.

The research confirms an increasing fear that global heating driven by profligate human use of fossil fuels could tip not just climate but also natural landscapes into a new and potentially catastrophic states.

Dramatic warning

More directly, as reported in an interview with Brazilian scientist Antonio Donato Nobre in Climate News Network yesterday, it confirms a dramatic warning delivered in December last year that the Amazon rainforest – a landscape almost as vast as the entire 48 contiguous states of the US – may already be teetering on the edge of functional disruption.

How this disruption could happen was recently outlined by two scientists, Thomas Lovejoy, professor of biology at George Mason University in Virginia, US, and Carlos Nobre, a leading expert on the Amazon and climate change, who is the brother of Antonio Donato Nobre and is senior researcher at the University of Saõ Paulo’s Institute for Advanced Studies.

Lovejoy and Carlos Nobre point out that most of the rain that keeps the Amazon a rainforest is actually recycled from the dense canopy that covers the region. After rainfall, evapotranspiration from the foliage returns water vapour to the air above the forest and falls anew as rain, again and again.

“Over the whole basin, the air rises, cools and precipitates out close to 20% of the world’s river water in the Amazon river system,” they warn in a Science journal report.

“Current deforestation is substantial and frightening: 17% across the entire Amazon basin and approaching 20% in the Brazilian Amazon.

“Already there are ominous signals of it in nature. Dry seasons in the Amazon are already hotter and longer. Mortality rates of wet-climate species are increased, whereas dry-climate species are showing resilience. The increasing frequency of unprecedented droughts in 2005, 2010 and 2015/16 is signalling that the tipping point is at hand.”

By contrast, the latest study in Nature Communications zeroes in on the rates at which large ecosystems could, in principle, change once the climate has begun to shift and the natural habitat is in some way degraded.

“This is yet another strong argument to avoid degrading our planet’s ecosystems; we need to do more to conserve biodiversity.”

Three scientists in the UK used computer models to test data from four terrestrial landscapes, 25 marine habitats and 13 freshwater ecosystems. They found, not surprisingly, that larger ecosystems tend to undergo regime shifts more slowly than the smaller ones.

However, as the ecosystem gets bigger, the additional time taken for collapse to happen gets briefer, so big ecosystems fail relatively more quickly.

This would mean that it would take 15 years for 20,000 sq km of Caribbean reef system to collapse, once some fatal trigger point had been reached. And the 5.5 million sq km of the Amazon tropical moist forest, once it starts to go, could be gone in just 49 years.

“Unfortunately, what our paper reveals is that humanity needs to prepare for change far sooner than expected,” says Simon Willcock, senior lecturer in environmental geography at Bangor University in Wales.

And his colleague, Dr Gregory Cooper, postdoctoral research fellow at the University of London’s Centre for Development, Environment and Policy, says: “This is yet another strong argument to avoid degrading our planet’s ecosystems; we need to do more to conserve biodiversity.”

Atmospheric carbon

Other researchers have separately found that the Amazon rainforest could be about to become a source of yet more atmospheric carbon – rather than a green machine for absorbing surplus carbon dioxide from the atmosphere – as a result of climate change and environmental destruction.

The Amazon ecosystem took 58 million years to evolve. But the message is that it could unravel in a very short time.

Alexandre Antonelli, director of science at the Royal Botanic Gardens at Kew, London, was not one of the researchers, but he describes the results of the study as “terrifying” and warns that the Amazon could pass the point of no return this year.

He says: “Nature is fragile. Just because an area is big or a species is common, it doesn’t mean they’ll last forever.

“The Sahel – an area south of the Sahara that is six times the size of Spain – went from being vegetated and bountiful to just a desert in a few hundred years.

“The American chestnut – one of the most important trees of eastern North America – almost faced extinction after a fungal disease caused some three to four billion trees to die in the early 1900s.

“Natural ecosystems are usually resilient to change when kept intact, but after decades of disruption, exploitation and climatic stress, it should come as no surprise that they are breaking down.

“In other words, you can’t simply remove huge chunks of a rainforest and hope everything will be fine – it won’t. Based on these results, 2020 is our very last opportunity to stop Amazonian deforestation.” – Climate News Network

Tropical forests may be heating Earth by 2035

Climate change so far has meant more vigorous forest growth as greenhouse gases rise. The tropical forests may soon change that.

LONDON, 6 March, 2020 – Within about fifteen years, the great tropical forests of Amazonia and Africa could stop absorbing atmospheric carbon, and slowly start to release more carbon than growing trees can fix.

A team of scientists from 100 research institutions has looked at the evidence from pristine tracts of tropical forest to find that – overall – the foliage soaked up the most carbon, most efficiently, more than two decades ago.

Since then, the measured efficiency of the forests as a “sink” in which carbon is sequestered from the atmosphere has been dwindling. By the last decade, the ability of a tropical forest to absorb carbon had dropped by a third.

All plant growth is a balancing act based on sunshine and atmospheric carbon and rainfall. Plants absorb carbon dioxide as they grow, and surrender it as they die.

In a dense, undisturbed wilderness, fallen leaves and even fallen trees are slightly less likely to decompose completely: the atmospheric carbon in leaf and wood form has a better chance of being preserved in flooded forests as peat, or being buried before it can completely decompose.

The forest becomes a bank vault, repository or sink of the extra carbon that humans are now spilling into the atmosphere from car exhausts, factory chimneys and power station furnaces.

Theory and practice

And in theory, as more and more carbon dioxide gets into the atmosphere, plants respond to the more generous fertilisation by growing more vigorously, and absorbing more carbon.

But as more carbon gets into the atmosphere, the temperature rises and weather patterns begin to become more extreme. Summers get hotter, rainfall more capricious. Then trees become vulnerable to drought, forest fire and invasive diseases, and die more often, and decompose more completely.

Wannes Hubau, once of the University of Leeds in the UK and now at the Royal Museum for Central Africa in Belgium, and more than 100 colleagues from around the world, report in the journal Nature that they assembled 30 years of measurement from more than 300,000 trees in 244 undisturbed plots of forest in 11 countries in Africa, and from 321 plots of forest in Amazonia, and did the sums.

In the 1990s, intact tropical forests removed around 46 billion tonnes of carbon dioxide from the atmosphere. By the 2010s, the uptake had fallen to around 25 billion tonnes. This means that 21 billion tons of greenhouse gas that might otherwise have been turned into timber and root had been added to the atmosphere.

This is pretty much what the UK, France, Germany and Canada together spilled into the atmosphere from fossil fuel combustion over a 10-year period.

“We’ve found one of the most worrying impacts of climate change has already begun. This is decades ahead of even the most pessimistic climate models”

“Extra carbon boosts tree growth, but every year this effect is being increasingly countered by the negative impacts of higher temperatures and droughts which slow growth and can kill trees,” said Dr Hubau.

“Our modeling shows a long-term decline in the African sink and that the Amazon sink will continue to rapidly weaken, which we predict will become a carbon source in the mid-2030s.”

Tropical forests are an integral factor in the planetary carbon budget – a crude accounting system that climate scientists rely upon to model the choice of futures that face humankind as the world heats up.

Around half of Earth’s carbon is stored in terrestrial vegetation and the tropical forests account for about a third of the planet’s primary productivity. So how forests respond to a warmer world is vital.

Because the Amazon region is being hit by higher temperatures, and more frequent and prolonged droughts than forests in tropical Africa, Amazonia is weakening at a faster rate.

But decline has also begun in Africa. In the 1990s, the undisturbed tropical forests alone inhaled 17% of human-made carbon dioxide emissions. In the decade just ended, this proportion fell to 6%.

Catastrophic prospect

In roughly the same period, the area of intact forest fell by 19%, and global carbon dioxide emissions rose by 46%. Even so, the tropical forests store 250 billion tonnes of carbon in their trees alone: 90 years of fossil fuel emissions at the present rate. So their sustained loss would be catastrophic.

“Intact tropical forests remain a vital carbon sink but this research reveals that unless policies are put in place to stabilise the Earth’s climate, it is only a matter of time until they are no longer able to sequester carbon,” said Simon Lewis, a geographer at the University of Leeds, and one of the authors.

“One big concern for the future of humanity is when carbon-cycle feedbacks really kick in, with nature switching from slowing climate change to accelerating it.

“After years of work deep in the Congo and Amazon rainforests, we’ve found one of the most worrying impacts of climate change has already begun.

“This is decades ahead of even the most pessimistic climate models. There is no time to lose in tackling climate change.” – Climate News Network

Climate change so far has meant more vigorous forest growth as greenhouse gases rise. The tropical forests may soon change that.

LONDON, 6 March, 2020 – Within about fifteen years, the great tropical forests of Amazonia and Africa could stop absorbing atmospheric carbon, and slowly start to release more carbon than growing trees can fix.

A team of scientists from 100 research institutions has looked at the evidence from pristine tracts of tropical forest to find that – overall – the foliage soaked up the most carbon, most efficiently, more than two decades ago.

Since then, the measured efficiency of the forests as a “sink” in which carbon is sequestered from the atmosphere has been dwindling. By the last decade, the ability of a tropical forest to absorb carbon had dropped by a third.

All plant growth is a balancing act based on sunshine and atmospheric carbon and rainfall. Plants absorb carbon dioxide as they grow, and surrender it as they die.

In a dense, undisturbed wilderness, fallen leaves and even fallen trees are slightly less likely to decompose completely: the atmospheric carbon in leaf and wood form has a better chance of being preserved in flooded forests as peat, or being buried before it can completely decompose.

The forest becomes a bank vault, repository or sink of the extra carbon that humans are now spilling into the atmosphere from car exhausts, factory chimneys and power station furnaces.

Theory and practice

And in theory, as more and more carbon dioxide gets into the atmosphere, plants respond to the more generous fertilisation by growing more vigorously, and absorbing more carbon.

But as more carbon gets into the atmosphere, the temperature rises and weather patterns begin to become more extreme. Summers get hotter, rainfall more capricious. Then trees become vulnerable to drought, forest fire and invasive diseases, and die more often, and decompose more completely.

Wannes Hubau, once of the University of Leeds in the UK and now at the Royal Museum for Central Africa in Belgium, and more than 100 colleagues from around the world, report in the journal Nature that they assembled 30 years of measurement from more than 300,000 trees in 244 undisturbed plots of forest in 11 countries in Africa, and from 321 plots of forest in Amazonia, and did the sums.

In the 1990s, intact tropical forests removed around 46 billion tonnes of carbon dioxide from the atmosphere. By the 2010s, the uptake had fallen to around 25 billion tonnes. This means that 21 billion tons of greenhouse gas that might otherwise have been turned into timber and root had been added to the atmosphere.

This is pretty much what the UK, France, Germany and Canada together spilled into the atmosphere from fossil fuel combustion over a 10-year period.

“We’ve found one of the most worrying impacts of climate change has already begun. This is decades ahead of even the most pessimistic climate models”

“Extra carbon boosts tree growth, but every year this effect is being increasingly countered by the negative impacts of higher temperatures and droughts which slow growth and can kill trees,” said Dr Hubau.

“Our modeling shows a long-term decline in the African sink and that the Amazon sink will continue to rapidly weaken, which we predict will become a carbon source in the mid-2030s.”

Tropical forests are an integral factor in the planetary carbon budget – a crude accounting system that climate scientists rely upon to model the choice of futures that face humankind as the world heats up.

Around half of Earth’s carbon is stored in terrestrial vegetation and the tropical forests account for about a third of the planet’s primary productivity. So how forests respond to a warmer world is vital.

Because the Amazon region is being hit by higher temperatures, and more frequent and prolonged droughts than forests in tropical Africa, Amazonia is weakening at a faster rate.

But decline has also begun in Africa. In the 1990s, the undisturbed tropical forests alone inhaled 17% of human-made carbon dioxide emissions. In the decade just ended, this proportion fell to 6%.

Catastrophic prospect

In roughly the same period, the area of intact forest fell by 19%, and global carbon dioxide emissions rose by 46%. Even so, the tropical forests store 250 billion tonnes of carbon in their trees alone: 90 years of fossil fuel emissions at the present rate. So their sustained loss would be catastrophic.

“Intact tropical forests remain a vital carbon sink but this research reveals that unless policies are put in place to stabilise the Earth’s climate, it is only a matter of time until they are no longer able to sequester carbon,” said Simon Lewis, a geographer at the University of Leeds, and one of the authors.

“One big concern for the future of humanity is when carbon-cycle feedbacks really kick in, with nature switching from slowing climate change to accelerating it.

“After years of work deep in the Congo and Amazon rainforests, we’ve found one of the most worrying impacts of climate change has already begun.

“This is decades ahead of even the most pessimistic climate models. There is no time to lose in tackling climate change.” – Climate News Network

A third of plants and animals risk mass extinction

As planetary temperatures rise, the chances of species survival lessen. Mass extinction is coming. The challenge is to measure the loss.

LONDON, 25 February, 2020 – Within 50 years, a third of all plant and animal species could be caught up in a mass extinction, as a consequence of climate change driven by ever-rising temperatures. What is new about this warning is the method, the precision, the timetable and the identification of a cause.

And – entirely felicitously – support for the prediction is backed by a series of separate studies of individual species survival in a world rapidly warming because of human commitment to fossil fuels.

Tiny marsupial insect-hunters in Australia could, on the evidence of direct experiment, fail to adapt to ever-higher thermometer readings, and quietly disappear.

As frogs and other amphibians in Central America are wiped out by invasive fungal pathogens – perhaps assisted by climate change – a set of snake species that prey upon them have also become increasingly at risk.

And directly because the Arctic is warming faster than anywhere else on the planet, the polar bears of Baffin Bay in Canada are thinner than they were 30 years ago, and have fewer cubs. That’s because Ursus maritimus hunts its seal prey on the sea ice. And as the winter ice forms later and melts earlier each decade, the bears have begun to go hungry.

Biologists, ecologists and conservationists have been warning for four decades that planet Earth could be on the edge of a sixth Great Extinction, as a simple consequence of the growth of human numbers and human economies, and the parallel destruction of natural habitat.

They have also repeatedly warned that climate change driven by human-triggered planetary heating would inevitably accelerate the losses.

Repeated surveys

But researchers from the University of Arizona have now confirmed the climate connection by using another approach: they decided to look directly at the numbers. They report in the Proceedings of the National Academy of Sciences that they selected data from 538 species and 581 places around the globe: they chose these numbers and sites because they could be sure that specific animal and plant species had been repeatedly surveyed over intervals of at least a decade.

They also factored in the changes in local climate conditions at each site, and isolated 19 different variables in the climate machine to work out what it could be about global heating that would directly pose the most significant threats. They also considered the options open to their chosen species: could these, for instance, migrate easily, or tolerate longer periods of extreme heat?

And then they did the calculations. They found that 50% of the chosen species went extinct locally if temperatures rose by more than 0.5°C, and 95% if the mercury reached an additional 2.9°C.

In the last century, the planet has warmed by 1°C above the average for most of human history and prehistory. Right now, thanks to ever-increasing fossil fuel use and continued forest destruction, the planet could be more than 3°C warmer by 2100.

But the researchers also found that the climate factor most closely linked to the extinction of any population was simply the maximum annual count the hottest daily highs in summer.

This also implies that extinction could be two or even four times as frequent in the tropics as in the temperate zones: it is in the tropics – the reefs, the rainforests, the wetlands and savannahs – that the world’s species are concentrated.

Antechinis flavipes, or yellow-footed antechinus, is a native Australian: it is not exactly a mole, or a mouse, or a shrew. It is a little marsupial carnivore with an unhappy love life: males mate in a frenzy and then tend to die from stress-related immune system breakdown.

“If we stick to the Paris Agreement to combat climate change, we may lose fewer than two out of every 10 plant and animal species by 2070. But if humans cause larger temperature increases, we could lose more than a third or even half”

It is also sensitive to temperature. When the mercury drops, the creature can go into a torpor and once comatose can even sleep through a bushfire.

Norwegian scientists report in the journal Frontiers in Physiology that they exposed 19 captive juveniles to spells of cold (17°C) and hot (25°C) temperatures, measured their growth and metabolic rate, and observed changes in behaviour. They conclude that, while individuals of the species can cope with short periods of high temperature, they may not have any way of surviving extended heat extremes.

Which is a problem for antechinus, because all the predictions for Australia – and indeed most of the planet – is that as the century proceeds and ever more greenhouse gases build up in the atmosphere, the hottest spells will become hotter, more frequent and more extended.

North American researchers have been tracking the polar bears who hunt seals and mate in Baffin Bay, between north-eastern Canada and Greenland, for almost three decades. They report in the journal Ecological Applications that when sea ice retreats, the bears wait on Baffin Island and live on their accumulated fat.

In the 1990s, the average stay on land – and away from the bears’ preferred prey – was 60 days. In the last decade, this rose to 90 days. Sampled females proved to be thinner than they had been, and were more likely to have one cub rather than two, all because unseasonally high temperatures in the Arctic mean that the hunting season on the ice is becoming ever shorter.

In 2004, the population of amphibians in a national park in Panama started to perish on a huge scale, and an estimated 30 species of frog and other creatures all but vanished in the wake of a pathogen fungus outbreak.

US scientists report in the journal Science that they set out to look at their wildlife observational data before and after the outbreak to measure the effect on the region’s snake species that prey on amphibians.

Rarely observed snakes

Even though the scientists logged 594 surveys in the seven years before the outbreak and 513 in the six years that followed, they had to use mathematical techniques to come up with probabilities of local snake extinction, because snakes are hard to observe at any time. Of the 36 snake species recorded there, 12 have been observed only once, and five only twice.

The bad news is there is an 85% probability that there are now fewer snake species than there had been, simply because of the disappearance of amphibian prey.

The study also highlights another worry for conservationists and ecologists: extinction of species is happening at an accelerating rate, but biologists still cannot put a number to the total of species at risk. Most of them have never been described or named. Like some of the snakes of Panama, they will have gone before scientists even knew they were there.

The climate connection with the worldwide loss of amphibian species is still uncertain. The certainty is that climate change will make life too hot for many species that – because what was once wilderness has now been cleared for cities, quarries, farms and commercial plantations – can no longer shift to cooler terrain.

John Wiens of the University of Arizona, one of the authors behind the research that predicts massive extinctions by 2070, thinks there is something that can be done.

In 2015 in Paris more than 190 nations vowed to act to contain global warming to “well below” 2°C. “In a way, it’s a ‘choose your own adventure,’” he said.

“If we stick to the Paris Agreement to combat climate change, we may lose fewer than two out of every 10 plant and animal species on Earth by 2070. But if humans cause larger temperature increases, we could lose more than a third or even half of all animal and plant species, based on our results.” – Climate News Network

As planetary temperatures rise, the chances of species survival lessen. Mass extinction is coming. The challenge is to measure the loss.

LONDON, 25 February, 2020 – Within 50 years, a third of all plant and animal species could be caught up in a mass extinction, as a consequence of climate change driven by ever-rising temperatures. What is new about this warning is the method, the precision, the timetable and the identification of a cause.

And – entirely felicitously – support for the prediction is backed by a series of separate studies of individual species survival in a world rapidly warming because of human commitment to fossil fuels.

Tiny marsupial insect-hunters in Australia could, on the evidence of direct experiment, fail to adapt to ever-higher thermometer readings, and quietly disappear.

As frogs and other amphibians in Central America are wiped out by invasive fungal pathogens – perhaps assisted by climate change – a set of snake species that prey upon them have also become increasingly at risk.

And directly because the Arctic is warming faster than anywhere else on the planet, the polar bears of Baffin Bay in Canada are thinner than they were 30 years ago, and have fewer cubs. That’s because Ursus maritimus hunts its seal prey on the sea ice. And as the winter ice forms later and melts earlier each decade, the bears have begun to go hungry.

Biologists, ecologists and conservationists have been warning for four decades that planet Earth could be on the edge of a sixth Great Extinction, as a simple consequence of the growth of human numbers and human economies, and the parallel destruction of natural habitat.

They have also repeatedly warned that climate change driven by human-triggered planetary heating would inevitably accelerate the losses.

Repeated surveys

But researchers from the University of Arizona have now confirmed the climate connection by using another approach: they decided to look directly at the numbers. They report in the Proceedings of the National Academy of Sciences that they selected data from 538 species and 581 places around the globe: they chose these numbers and sites because they could be sure that specific animal and plant species had been repeatedly surveyed over intervals of at least a decade.

They also factored in the changes in local climate conditions at each site, and isolated 19 different variables in the climate machine to work out what it could be about global heating that would directly pose the most significant threats. They also considered the options open to their chosen species: could these, for instance, migrate easily, or tolerate longer periods of extreme heat?

And then they did the calculations. They found that 50% of the chosen species went extinct locally if temperatures rose by more than 0.5°C, and 95% if the mercury reached an additional 2.9°C.

In the last century, the planet has warmed by 1°C above the average for most of human history and prehistory. Right now, thanks to ever-increasing fossil fuel use and continued forest destruction, the planet could be more than 3°C warmer by 2100.

But the researchers also found that the climate factor most closely linked to the extinction of any population was simply the maximum annual count the hottest daily highs in summer.

This also implies that extinction could be two or even four times as frequent in the tropics as in the temperate zones: it is in the tropics – the reefs, the rainforests, the wetlands and savannahs – that the world’s species are concentrated.

Antechinis flavipes, or yellow-footed antechinus, is a native Australian: it is not exactly a mole, or a mouse, or a shrew. It is a little marsupial carnivore with an unhappy love life: males mate in a frenzy and then tend to die from stress-related immune system breakdown.

“If we stick to the Paris Agreement to combat climate change, we may lose fewer than two out of every 10 plant and animal species by 2070. But if humans cause larger temperature increases, we could lose more than a third or even half”

It is also sensitive to temperature. When the mercury drops, the creature can go into a torpor and once comatose can even sleep through a bushfire.

Norwegian scientists report in the journal Frontiers in Physiology that they exposed 19 captive juveniles to spells of cold (17°C) and hot (25°C) temperatures, measured their growth and metabolic rate, and observed changes in behaviour. They conclude that, while individuals of the species can cope with short periods of high temperature, they may not have any way of surviving extended heat extremes.

Which is a problem for antechinus, because all the predictions for Australia – and indeed most of the planet – is that as the century proceeds and ever more greenhouse gases build up in the atmosphere, the hottest spells will become hotter, more frequent and more extended.

North American researchers have been tracking the polar bears who hunt seals and mate in Baffin Bay, between north-eastern Canada and Greenland, for almost three decades. They report in the journal Ecological Applications that when sea ice retreats, the bears wait on Baffin Island and live on their accumulated fat.

In the 1990s, the average stay on land – and away from the bears’ preferred prey – was 60 days. In the last decade, this rose to 90 days. Sampled females proved to be thinner than they had been, and were more likely to have one cub rather than two, all because unseasonally high temperatures in the Arctic mean that the hunting season on the ice is becoming ever shorter.

In 2004, the population of amphibians in a national park in Panama started to perish on a huge scale, and an estimated 30 species of frog and other creatures all but vanished in the wake of a pathogen fungus outbreak.

US scientists report in the journal Science that they set out to look at their wildlife observational data before and after the outbreak to measure the effect on the region’s snake species that prey on amphibians.

Rarely observed snakes

Even though the scientists logged 594 surveys in the seven years before the outbreak and 513 in the six years that followed, they had to use mathematical techniques to come up with probabilities of local snake extinction, because snakes are hard to observe at any time. Of the 36 snake species recorded there, 12 have been observed only once, and five only twice.

The bad news is there is an 85% probability that there are now fewer snake species than there had been, simply because of the disappearance of amphibian prey.

The study also highlights another worry for conservationists and ecologists: extinction of species is happening at an accelerating rate, but biologists still cannot put a number to the total of species at risk. Most of them have never been described or named. Like some of the snakes of Panama, they will have gone before scientists even knew they were there.

The climate connection with the worldwide loss of amphibian species is still uncertain. The certainty is that climate change will make life too hot for many species that – because what was once wilderness has now been cleared for cities, quarries, farms and commercial plantations – can no longer shift to cooler terrain.

John Wiens of the University of Arizona, one of the authors behind the research that predicts massive extinctions by 2070, thinks there is something that can be done.

In 2015 in Paris more than 190 nations vowed to act to contain global warming to “well below” 2°C. “In a way, it’s a ‘choose your own adventure,’” he said.

“If we stick to the Paris Agreement to combat climate change, we may lose fewer than two out of every 10 plant and animal species on Earth by 2070. But if humans cause larger temperature increases, we could lose more than a third or even half of all animal and plant species, based on our results.” – Climate News Network

Greenhouse gases have a puzzling double effect

Lustier plant growth as greenhouse gases climb should counter global heating and atmospheric carbon build-up. But it’s not quite so simple.

LONDON, 21 February, 2020 – The Arctic is getting greener as greenhouse gases abound and the global thermometer rises. The vegetation of the high latitudes is moving further north, growing taller, becoming more substantial, more abundant and budding earlier, according to new studies by 40 scientists from 36 European and US institutions.

And the whole planet is getting greener too, according to a separate study in a second journal, as more carbon dioxide in the atmosphere – the chief cause of global heating – also acts as a fertiliser to stimulate plant growth.

It is as if researchers have finally identified a genuine negative feedback effect: as the world warms because of higher levels of greenhouse gases, the plant world responds by absorbing more of the carbon in the atmosphere and modifying the overall impact.

But both studies identify problems with what might be a comforting conclusion: it isn’t clear why in some Arctic regions the green things are getting greener, while in others the vegetation cover is becoming poorer.

And worldwide, it might be that much of the global greening can be attributed to human action – the advance of industrial-scale agriculture and commercial forest plantation – in which case most of the absorbed carbon dioxide will be returned to the atmosphere sooner or later.

“It is ironic that the very same carbon emissions responsible for harmful changes to climate are also fertilising plant growth, which in turn is somewhat moderating global warming”

Both studies confirm the value of a closer look at the evidence so far – and the need for further study.

In the journal Nature Climate Change, scientists report that they checked the big picture of polar greening based on four decades of data from large-scale satellite observation against more detailed evidence over smaller sample regions collected by sensors mounted on drones and on aircraft, as well as direct examination on the once-frozen ground.

The Arctic is the fastest-warming region of the planet: it is warming twice as fast as the globe as a whole. Snow melts earlier, plants leaf sooner. Shrubs that once stayed close to the slushy snow surface are now taller, and new species are colonising once hostile terrain.

This is expected to destabilise the Arctic tundra, the region of year-round permafrost that masks a vast reservoir of carbon buried in the frozen soils.

Natural response

So botanists and climate scientists in the high latitudes now have to begin some tricky calculations in their pursuit of reliable estimates of the global carbon budget. How much carbon will the new green growth absorb and store? And how much carbon buried for the last 100,000 years or so will escape into the atmosphere with the advance of the northern greenery and the thawing of the soils?

But at least, according to a paper in the journal Nature Reviews Earth and Environment, the observed greening of the Arctic is a natural response to rising average temperatures and greater carbon dioxide fertilisation as a consequence of ever-higher levels of greenhouse gas emissions and consequent climate change.

Svalbard in the high Arctic is almost 2°C warmer in summer than it was in 1986, and at least 30% greener. But the Arctic is a region with limited human settlement and low industrial investment.

A team of researchers from China, the US, France and Norway combed through 250 earlier studies, and revisited satellite data, climate models and field observations, to make sense of the evidence of a planet that has grown a lot greener: half of all the world’s vegetated lands are leafier than they once were.

And they concluded that it was possible that the growth of global greening in the last 40 years may have slowed the rate of global heating by as much as 0.25°C.

Human footprint

But the same greening can be seen as evidence of rapid human impact on the planet as a whole: much of it can be explained by more intensive use of farmland and forest plantation, especially in the world’s most populous countries, India and China.

“It is ironic that the very same carbon emissions responsible for harmful changes to climate are also fertilising plant growth, which in turn is somewhat moderating global warming,” said one author, Jarle Bjerke of the Norwegian Institute for Nature Research.

And his co-author Phillipe Ciais, of France’s Laboratory of Climate and Environmental Sciences, said: “Plants are actively defending against the dangers of carbon pollution by not only sequestering carbon on land but also by wetting the atmosphere through transpiration of ground water and evaporation of precipitation intercepted by their bodies.

“Stopping deforestation and promoting sustainable, ecologically sensible afforestation could be one of the simplest and most cost-effective, though not sufficient, defences against climate change.” – Climate News Network

Lustier plant growth as greenhouse gases climb should counter global heating and atmospheric carbon build-up. But it’s not quite so simple.

LONDON, 21 February, 2020 – The Arctic is getting greener as greenhouse gases abound and the global thermometer rises. The vegetation of the high latitudes is moving further north, growing taller, becoming more substantial, more abundant and budding earlier, according to new studies by 40 scientists from 36 European and US institutions.

And the whole planet is getting greener too, according to a separate study in a second journal, as more carbon dioxide in the atmosphere – the chief cause of global heating – also acts as a fertiliser to stimulate plant growth.

It is as if researchers have finally identified a genuine negative feedback effect: as the world warms because of higher levels of greenhouse gases, the plant world responds by absorbing more of the carbon in the atmosphere and modifying the overall impact.

But both studies identify problems with what might be a comforting conclusion: it isn’t clear why in some Arctic regions the green things are getting greener, while in others the vegetation cover is becoming poorer.

And worldwide, it might be that much of the global greening can be attributed to human action – the advance of industrial-scale agriculture and commercial forest plantation – in which case most of the absorbed carbon dioxide will be returned to the atmosphere sooner or later.

“It is ironic that the very same carbon emissions responsible for harmful changes to climate are also fertilising plant growth, which in turn is somewhat moderating global warming”

Both studies confirm the value of a closer look at the evidence so far – and the need for further study.

In the journal Nature Climate Change, scientists report that they checked the big picture of polar greening based on four decades of data from large-scale satellite observation against more detailed evidence over smaller sample regions collected by sensors mounted on drones and on aircraft, as well as direct examination on the once-frozen ground.

The Arctic is the fastest-warming region of the planet: it is warming twice as fast as the globe as a whole. Snow melts earlier, plants leaf sooner. Shrubs that once stayed close to the slushy snow surface are now taller, and new species are colonising once hostile terrain.

This is expected to destabilise the Arctic tundra, the region of year-round permafrost that masks a vast reservoir of carbon buried in the frozen soils.

Natural response

So botanists and climate scientists in the high latitudes now have to begin some tricky calculations in their pursuit of reliable estimates of the global carbon budget. How much carbon will the new green growth absorb and store? And how much carbon buried for the last 100,000 years or so will escape into the atmosphere with the advance of the northern greenery and the thawing of the soils?

But at least, according to a paper in the journal Nature Reviews Earth and Environment, the observed greening of the Arctic is a natural response to rising average temperatures and greater carbon dioxide fertilisation as a consequence of ever-higher levels of greenhouse gas emissions and consequent climate change.

Svalbard in the high Arctic is almost 2°C warmer in summer than it was in 1986, and at least 30% greener. But the Arctic is a region with limited human settlement and low industrial investment.

A team of researchers from China, the US, France and Norway combed through 250 earlier studies, and revisited satellite data, climate models and field observations, to make sense of the evidence of a planet that has grown a lot greener: half of all the world’s vegetated lands are leafier than they once were.

And they concluded that it was possible that the growth of global greening in the last 40 years may have slowed the rate of global heating by as much as 0.25°C.

Human footprint

But the same greening can be seen as evidence of rapid human impact on the planet as a whole: much of it can be explained by more intensive use of farmland and forest plantation, especially in the world’s most populous countries, India and China.

“It is ironic that the very same carbon emissions responsible for harmful changes to climate are also fertilising plant growth, which in turn is somewhat moderating global warming,” said one author, Jarle Bjerke of the Norwegian Institute for Nature Research.

And his co-author Phillipe Ciais, of France’s Laboratory of Climate and Environmental Sciences, said: “Plants are actively defending against the dangers of carbon pollution by not only sequestering carbon on land but also by wetting the atmosphere through transpiration of ground water and evaporation of precipitation intercepted by their bodies.

“Stopping deforestation and promoting sustainable, ecologically sensible afforestation could be one of the simplest and most cost-effective, though not sufficient, defences against climate change.” – Climate News Network

Many species face threat of insect extinction

Rainforests can get too hot for beetles. Mayflies can succumb to seasonal change, bumblebees to drought. Insect extinction may soon await myriad species.

LONDON, 13 February, 2020 – Humankind could be about to bid farewell to friends it never got to know, as insect extinction overtakes countless species.

Most of the millions of insects that support life on the planet have yet to be named or described. And yet perhaps 500,000 species of beetles, butterflies, bees, ants and other six-legged creatures vital to the efficient working of natural ecosystems and commercial economies could be about to disappear – as a consequence of climate change and other pressures driven by human population growth.

And this note of alarm has been sounded within a few days in which other research groups have separately warned of the climate threats to beetles in the Amazon forest, to the burrowing mayflies of the American mid-west and to the bumblebees of North America and Europe.

Insects pollinate growing plants, dispose of dying ones and serve as lunch or supper for birds, amphibians, reptiles, bats and other mammals. There could be as many as 5.5 million distinct species of insect, of which no more than one in five has been observed, identified and catalogued by entomologists.

A million or more creatures fashioned by aeons of evolution and natural selection could be at imminent risk of extinction because of human advance. A group of 30 experts now urgently warns in the journal Biological Conservation that half of these could be insects.

“From pollination and decomposition, to being resources for new medicines, insects provide essential and irreplaceable services”

“It is surprising how little we know about biodiversity at a global level, when only about 10 to 20% of insect and other invertebrate species have been described and named. And of those with a name, we know little more than a brief morphological description, maybe part of the genetic code and a single site where it was seen some years ago,” said Pedro Cardoso, of the Finnish Museum of Natural History in Helsinki, who led the study.

“With species loss, we lose not only another piece of the complex puzzle that is our living world, but also biomass, essential to feed other animals in the living chain, unique genes and substances that might one day contribute to cure diseases, and ecosystem functions on which humanity depends.”

The researchers argue that insect species are vulnerable to human changes to their natural habitat; to pesticide and fertiliser use; to light pollution, industrial pollution and even noise pollution. Climate change driven by fossil fuel combustion amplifies the hazard: the unfamiliar seasonal temperatures and the advance of spring mean for instance that butterflies have emerged ahead of the nectar plants that normally nourish them.

And a series of separate studies explore some of the impact of human-triggered changes to natural systems. Researchers report in the journal Biotropica that hotter and drier episodes in the Amazon rainforests have led not only to disastrous fires but to a dramatic collapse of dung beetle populations.

Vanishing beetles

These little creatures spread nutrients and seeds, and ecologists see them as evidence of the overall health of an ecosystem, which is why international teams of scientists have been monitoring dung beetles from 98 species across 30 forest plots in the Brazilian state of Pará.

In 2010, they counted 8000 beetles. In 2017, after an El Niño event had brought drought and fire to the region, they found only 2,600.

Mayflies, too, are seen as indicators of the health of rivers, lakes and streams: the more there are, the better the water quality. The burrowing mayfly makes a spectacular emergence each year from US waterways to darken the skies. Researchers have estimated more than 87 billion insects in one swarm, weighing more than 3,000 tonnes of potential bird and fish food.

But researchers report in the Proceedings of the National Academy of Sciences that between 2015 and 2019 scientists used radar to monitor the swarms over Lake Erie and found that as a consequence of a warming climate and other pressures, numbers fell in that four-year sequence by 84%.

And in the journal Science, Canadian and British scientists report that they looked at more than a century of records of 66 species of bumblebee in North America and Europe, to find that, within one human generation, as global heating amplified the frequency of extreme temperatures and droughts, the likelihood of a bumblebee population surviving in a given place had fallen on average by 30%.

Not insects alone

That insects may be in trouble is not news: naturalists have measured huge losses over time in sample locations, often as a consequence of habitat destruction, but also as a consequence of local climate shifts in response to global heating. These losses have been mirrored in bird predator populations and even in changes in insects themselves.

As the authors of the Biological Conservation paper point out, the damage goes beyond the insect world. Other creatures depend on insects, directly or indirectly. So do humans.

“With insect extinctions, we lose much more than species,” Dr Cardoso and his colleagues write. “We lose abundance and biomass of insects, diversity across space and time with consequent homogenisation, large parts of the tree of life, unique ecological functions and traits, and fundamental parts of extensive networks of biotic interactions.

“Such losses lead to the decline of key ecosystem services on which humanity depends. From pollination and decomposition, to being resources for new medicines, habitat quality indication and many others, insects provide essential and irreplaceable services.” – Climate News Network

Rainforests can get too hot for beetles. Mayflies can succumb to seasonal change, bumblebees to drought. Insect extinction may soon await myriad species.

LONDON, 13 February, 2020 – Humankind could be about to bid farewell to friends it never got to know, as insect extinction overtakes countless species.

Most of the millions of insects that support life on the planet have yet to be named or described. And yet perhaps 500,000 species of beetles, butterflies, bees, ants and other six-legged creatures vital to the efficient working of natural ecosystems and commercial economies could be about to disappear – as a consequence of climate change and other pressures driven by human population growth.

And this note of alarm has been sounded within a few days in which other research groups have separately warned of the climate threats to beetles in the Amazon forest, to the burrowing mayflies of the American mid-west and to the bumblebees of North America and Europe.

Insects pollinate growing plants, dispose of dying ones and serve as lunch or supper for birds, amphibians, reptiles, bats and other mammals. There could be as many as 5.5 million distinct species of insect, of which no more than one in five has been observed, identified and catalogued by entomologists.

A million or more creatures fashioned by aeons of evolution and natural selection could be at imminent risk of extinction because of human advance. A group of 30 experts now urgently warns in the journal Biological Conservation that half of these could be insects.

“From pollination and decomposition, to being resources for new medicines, insects provide essential and irreplaceable services”

“It is surprising how little we know about biodiversity at a global level, when only about 10 to 20% of insect and other invertebrate species have been described and named. And of those with a name, we know little more than a brief morphological description, maybe part of the genetic code and a single site where it was seen some years ago,” said Pedro Cardoso, of the Finnish Museum of Natural History in Helsinki, who led the study.

“With species loss, we lose not only another piece of the complex puzzle that is our living world, but also biomass, essential to feed other animals in the living chain, unique genes and substances that might one day contribute to cure diseases, and ecosystem functions on which humanity depends.”

The researchers argue that insect species are vulnerable to human changes to their natural habitat; to pesticide and fertiliser use; to light pollution, industrial pollution and even noise pollution. Climate change driven by fossil fuel combustion amplifies the hazard: the unfamiliar seasonal temperatures and the advance of spring mean for instance that butterflies have emerged ahead of the nectar plants that normally nourish them.

And a series of separate studies explore some of the impact of human-triggered changes to natural systems. Researchers report in the journal Biotropica that hotter and drier episodes in the Amazon rainforests have led not only to disastrous fires but to a dramatic collapse of dung beetle populations.

Vanishing beetles

These little creatures spread nutrients and seeds, and ecologists see them as evidence of the overall health of an ecosystem, which is why international teams of scientists have been monitoring dung beetles from 98 species across 30 forest plots in the Brazilian state of Pará.

In 2010, they counted 8000 beetles. In 2017, after an El Niño event had brought drought and fire to the region, they found only 2,600.

Mayflies, too, are seen as indicators of the health of rivers, lakes and streams: the more there are, the better the water quality. The burrowing mayfly makes a spectacular emergence each year from US waterways to darken the skies. Researchers have estimated more than 87 billion insects in one swarm, weighing more than 3,000 tonnes of potential bird and fish food.

But researchers report in the Proceedings of the National Academy of Sciences that between 2015 and 2019 scientists used radar to monitor the swarms over Lake Erie and found that as a consequence of a warming climate and other pressures, numbers fell in that four-year sequence by 84%.

And in the journal Science, Canadian and British scientists report that they looked at more than a century of records of 66 species of bumblebee in North America and Europe, to find that, within one human generation, as global heating amplified the frequency of extreme temperatures and droughts, the likelihood of a bumblebee population surviving in a given place had fallen on average by 30%.

Not insects alone

That insects may be in trouble is not news: naturalists have measured huge losses over time in sample locations, often as a consequence of habitat destruction, but also as a consequence of local climate shifts in response to global heating. These losses have been mirrored in bird predator populations and even in changes in insects themselves.

As the authors of the Biological Conservation paper point out, the damage goes beyond the insect world. Other creatures depend on insects, directly or indirectly. So do humans.

“With insect extinctions, we lose much more than species,” Dr Cardoso and his colleagues write. “We lose abundance and biomass of insects, diversity across space and time with consequent homogenisation, large parts of the tree of life, unique ecological functions and traits, and fundamental parts of extensive networks of biotic interactions.

“Such losses lead to the decline of key ecosystem services on which humanity depends. From pollination and decomposition, to being resources for new medicines, habitat quality indication and many others, insects provide essential and irreplaceable services.” – Climate News Network