Tag Archives: Natural variability

Earth cooled naturally long before human heating

Once again the past shows the role of greenhouse gases in climate change. It also confirms human heating as the main cause of global warmth.

LONDON, 8 July, 2020 – A new reconstruction of the history of global temperatures for the last 12,000 years supports an argument often put forward by climate sceptics: that global climate is subject to natural cycles driven by astronomical forces and planet Earth might be in one, with human heating not responsible.

It is. But the latest finding offers no evidence for scepticism. For the last 6,500 years the global mean surface of the planet has slowly and  naturally been getting cooler, as lower levels of summer sunlight hit the northern hemisphere.

And this gradual cooling came to a sudden end only in the 19th century as human cities and industries switched increasingly to coal, and then to oil and gas, to return ever-higher levels of ancient carbon to the atmosphere.

The rate of natural cooling would be imperceptible in any human lifespan: less than 0.1°C per thousand years.

This slow, subtle lowering of the temperature began 4,500 years before the beginning of the Christian era, in a Neolithic world of perhaps only 40 million people, at a time when Chinese villagers began to grow rice on terraces along the Yellow River and civilisation began to flourish in the Tigris-Euphrates valley.

“This past decade was likely cooler than what the average temperatures will be for the rest of this century and beyond”

This was a time when the first agricultural and pastoral settlements spread across Europe, along with the first pottery; when the Sahara was still grassland, and when most of Europe spoke just one language, now called Proto-Indo-European.

Researchers from the US and Europe report in the journal Scientific Data that they used the most comprehensive collection of palaeo-climatic evidence – 1,319 data sets based on tree rings, fossil pollen samples, ice cores and so on, collected from 679 sites worldwide – to establish that this must have been, for humans in prehistory, the moment of what they call “peak warmth.” From then on, the thermometer began to drop, at an average of 0.08C per millennium.

“The rate of cooling that followed the peak warmth was subtle, only around 0.01°C per 1,000 years. This cooling seems to be driven by slow cycles in the Earth’s orbit, which reduced the amount of summer sunlight in the Northern Hemisphere, culminating in the Little Ice Age of recent centuries,” said Michael Erb of Northern Arizona University.

More than a century of observation has shown that tiny cyclic changes in the Earth’s elliptical orbit can explain some of the patterns of climate change in the past, and confirm the lengths of the more recent Ice Ages, and the role of other planets in these periodic shifts.

Big picture unchanged

It is an article of faith among geologists that the present is key to the past, and the rocks and fossils preserve enduring evidence of the ups and downs of global temperatures.

It is now four years since European scientists proposed that climate change driven by greenhouse gas emissions from fossil fuels might have begun to delay the next Ice Age.

So the latest look at more recent data doesn’t change the big picture. In the last 100 or more years, global temperatures have risen by at least 1°C, and the average temperature of the last decade has been the warmest for 12,000 years, thanks to increasing concentrations of carbon dioxide in the atmosphere, as a consequence of human action.

“On the other hand, this past decade was likely cooler than what the average temperatures will be for the rest of this century and beyond, which are very likely to continue to exceed 1°C above pre-industrial temperatures,” said Nicholas McKay, one of the authors from Flagstaff, Arizona.

And his colleague Darrell Kaufman, who led the study, said: “It’s possible that the last time the sustained average global temperature was 1°C above the 19th century was prior to the last Ice Age, back around 125,000 years ago when sea level was around 20 feet (6 metres) higher than today.” – Climate News Network

Once again the past shows the role of greenhouse gases in climate change. It also confirms human heating as the main cause of global warmth.

LONDON, 8 July, 2020 – A new reconstruction of the history of global temperatures for the last 12,000 years supports an argument often put forward by climate sceptics: that global climate is subject to natural cycles driven by astronomical forces and planet Earth might be in one, with human heating not responsible.

It is. But the latest finding offers no evidence for scepticism. For the last 6,500 years the global mean surface of the planet has slowly and  naturally been getting cooler, as lower levels of summer sunlight hit the northern hemisphere.

And this gradual cooling came to a sudden end only in the 19th century as human cities and industries switched increasingly to coal, and then to oil and gas, to return ever-higher levels of ancient carbon to the atmosphere.

The rate of natural cooling would be imperceptible in any human lifespan: less than 0.1°C per thousand years.

This slow, subtle lowering of the temperature began 4,500 years before the beginning of the Christian era, in a Neolithic world of perhaps only 40 million people, at a time when Chinese villagers began to grow rice on terraces along the Yellow River and civilisation began to flourish in the Tigris-Euphrates valley.

“This past decade was likely cooler than what the average temperatures will be for the rest of this century and beyond”

This was a time when the first agricultural and pastoral settlements spread across Europe, along with the first pottery; when the Sahara was still grassland, and when most of Europe spoke just one language, now called Proto-Indo-European.

Researchers from the US and Europe report in the journal Scientific Data that they used the most comprehensive collection of palaeo-climatic evidence – 1,319 data sets based on tree rings, fossil pollen samples, ice cores and so on, collected from 679 sites worldwide – to establish that this must have been, for humans in prehistory, the moment of what they call “peak warmth.” From then on, the thermometer began to drop, at an average of 0.08C per millennium.

“The rate of cooling that followed the peak warmth was subtle, only around 0.01°C per 1,000 years. This cooling seems to be driven by slow cycles in the Earth’s orbit, which reduced the amount of summer sunlight in the Northern Hemisphere, culminating in the Little Ice Age of recent centuries,” said Michael Erb of Northern Arizona University.

More than a century of observation has shown that tiny cyclic changes in the Earth’s elliptical orbit can explain some of the patterns of climate change in the past, and confirm the lengths of the more recent Ice Ages, and the role of other planets in these periodic shifts.

Big picture unchanged

It is an article of faith among geologists that the present is key to the past, and the rocks and fossils preserve enduring evidence of the ups and downs of global temperatures.

It is now four years since European scientists proposed that climate change driven by greenhouse gas emissions from fossil fuels might have begun to delay the next Ice Age.

So the latest look at more recent data doesn’t change the big picture. In the last 100 or more years, global temperatures have risen by at least 1°C, and the average temperature of the last decade has been the warmest for 12,000 years, thanks to increasing concentrations of carbon dioxide in the atmosphere, as a consequence of human action.

“On the other hand, this past decade was likely cooler than what the average temperatures will be for the rest of this century and beyond, which are very likely to continue to exceed 1°C above pre-industrial temperatures,” said Nicholas McKay, one of the authors from Flagstaff, Arizona.

And his colleague Darrell Kaufman, who led the study, said: “It’s possible that the last time the sustained average global temperature was 1°C above the 19th century was prior to the last Ice Age, back around 125,000 years ago when sea level was around 20 feet (6 metres) higher than today.” – Climate News Network

Drought-hit forests may worsen climate change

Forests help to slow the challenge of climate change, don’t they? Only if climate change doesn’t fell the forests first.

LONDON, 7 July, 2020 − There could be big problems with national and international plans to plant forests to deal with climate change. One of them is uncertainty about how climate change is going to deal with the forests.

In six new studies of what might be called the plantation carbon conundrum, independent groups of researchers warn that:

That the loss of natural forests worldwide is a driver of global heating and climate change has never been in doubt. And climate scientists continue to count tomorrow’s forests as part of the answer to the threat of catastrophic climate change.

But researchers have already warned that a vow to plant one trillion trees is not of itself a readymade answer, and that national plans to conserve existing forest are less than effective.

So the challenge for foresters and ecologists is to decide what works best – and what would not. Researchers in the US argue in the journal Science that governments and policymakers need a masterplan to confront the risks forests face from the consequences of rising temperatures: drought, fire and insect disturbance.

Flying blind

Forests and other natural ecosystems absorb about one-third of all the greenhouse gas emissions that human actions release each year. New forests must be part of the answer, but only if the new timber goes on and on absorbing carbon.

“There’s a very real chance that many of those forest projects could go up in flames or to bugs or drought stress or hurricanes in the coming decades,” said William Anderegg of the University of Utah, who led the study. “Without good science to tell us what the risks are, we’re flying blind and not making the best policy decisions.”

The other papers look at aspects of the hazard, and of well-intentioned policies to combat climate change. The Bonn Challenge aims to restore an area of forest eight times the size of California, but 80% of the commitments so far involve plantations of single species or of exploitable species: fruit, for instance, and rubber on what might have been natural forest land, grassland or savannahs that support biodiversity.

Californian and Chilean researchers report in the journal Nature Sustainability that they looked at the role of long-running Chilean government subsidies in afforestation and found an uncomfortable result: exotic species flourished at the expense of native wilderness.

“Chile’s forest subsidies probably decreased biodiversity without increasing total carbon stored in aboveground biomass,” they conclude, bluntly. And one of the paper’s authors, Eric Lambin of Stanford University, spelled it out: “That’s the exact opposite of what these policies are aiming for.”

“Up until now, forests have stabilised the climate, but as they become more drought-stressed, they could become a destabilising carbon source”

German scientists report in the journal Basic and Applied Ecology that a warmer world has already delivered dramatic consequences for the forests of Germany, Austria and Switzerland.

The past five years have been the warmest in the region since records began, and 2018’s summer was the most extreme – 3.3°C above the long-term average. For spruce and other species that was the limit, and by 2019 even beech trees had died.

Since extreme drought and heat will become ever more likely, researchers need to decide what mix of species is going to survive and provide cover for threatened species. “This is going to take some time,” said Bernhard Schuldt, of the University of Würzburg.

Chinese and US researchers report in Nature Sustainability that they examined the same problems using a ground-up approach. They looked at 11,000 soil samples taken across 163 control and forested plots in northern China, to find that the carbon capture potential of afforestation schemes may have been overestimated. In soils low in carbon, plantation did increase the density of organic carbon. In those soils already rich in organic carbon, the planting seemed to lower carbon density.

European researchers, too, report in Science that they looked at data collected over 150 years at 6,000 locations to work out what happened to plants and animals as climate change and human intrusion transformed the world’s forests. Again, the answers are not simple.

No guarantee

“Surprisingly, we found that forest loss doesn’t always lead to biodiversity declines,” said Gergana Daskalova of the University of Edinburgh in Scotland. “Instead, when we lose forest cover, this can amplify the ongoing biodiversity change. For example, if a plant or animal species was declining before forest loss, its decline becomes even more severe.” Species already doing well, however, seemed to do better.

But there’s little guarantee that what works now will go on working, according to Arizona scientists writing in the journal Global Change Biology. So far, forests have helped contain climate change. But they found that North America’s most prolific tree, the Douglas fir, will absorb less carbon in future and do less to slow climate change.

They based their finding on examination of 2.7 million tree rings from 2,700 sites in the fir’s enormous ecological range. At the southern and warmest and driest end of this range, the decline in annual growth could be as high as 30%.

“More warming for trees could mean more stress, more tree death and less capacity to slow global warming,” said Margaret Evans, of the University of Arizona.

“Up until now, forests have stabilised the climate, but as they become more drought-stressed, they could become a destabilising carbon source.” − Climate News Network

Forests help to slow the challenge of climate change, don’t they? Only if climate change doesn’t fell the forests first.

LONDON, 7 July, 2020 − There could be big problems with national and international plans to plant forests to deal with climate change. One of them is uncertainty about how climate change is going to deal with the forests.

In six new studies of what might be called the plantation carbon conundrum, independent groups of researchers warn that:

That the loss of natural forests worldwide is a driver of global heating and climate change has never been in doubt. And climate scientists continue to count tomorrow’s forests as part of the answer to the threat of catastrophic climate change.

But researchers have already warned that a vow to plant one trillion trees is not of itself a readymade answer, and that national plans to conserve existing forest are less than effective.

So the challenge for foresters and ecologists is to decide what works best – and what would not. Researchers in the US argue in the journal Science that governments and policymakers need a masterplan to confront the risks forests face from the consequences of rising temperatures: drought, fire and insect disturbance.

Flying blind

Forests and other natural ecosystems absorb about one-third of all the greenhouse gas emissions that human actions release each year. New forests must be part of the answer, but only if the new timber goes on and on absorbing carbon.

“There’s a very real chance that many of those forest projects could go up in flames or to bugs or drought stress or hurricanes in the coming decades,” said William Anderegg of the University of Utah, who led the study. “Without good science to tell us what the risks are, we’re flying blind and not making the best policy decisions.”

The other papers look at aspects of the hazard, and of well-intentioned policies to combat climate change. The Bonn Challenge aims to restore an area of forest eight times the size of California, but 80% of the commitments so far involve plantations of single species or of exploitable species: fruit, for instance, and rubber on what might have been natural forest land, grassland or savannahs that support biodiversity.

Californian and Chilean researchers report in the journal Nature Sustainability that they looked at the role of long-running Chilean government subsidies in afforestation and found an uncomfortable result: exotic species flourished at the expense of native wilderness.

“Chile’s forest subsidies probably decreased biodiversity without increasing total carbon stored in aboveground biomass,” they conclude, bluntly. And one of the paper’s authors, Eric Lambin of Stanford University, spelled it out: “That’s the exact opposite of what these policies are aiming for.”

“Up until now, forests have stabilised the climate, but as they become more drought-stressed, they could become a destabilising carbon source”

German scientists report in the journal Basic and Applied Ecology that a warmer world has already delivered dramatic consequences for the forests of Germany, Austria and Switzerland.

The past five years have been the warmest in the region since records began, and 2018’s summer was the most extreme – 3.3°C above the long-term average. For spruce and other species that was the limit, and by 2019 even beech trees had died.

Since extreme drought and heat will become ever more likely, researchers need to decide what mix of species is going to survive and provide cover for threatened species. “This is going to take some time,” said Bernhard Schuldt, of the University of Würzburg.

Chinese and US researchers report in Nature Sustainability that they examined the same problems using a ground-up approach. They looked at 11,000 soil samples taken across 163 control and forested plots in northern China, to find that the carbon capture potential of afforestation schemes may have been overestimated. In soils low in carbon, plantation did increase the density of organic carbon. In those soils already rich in organic carbon, the planting seemed to lower carbon density.

European researchers, too, report in Science that they looked at data collected over 150 years at 6,000 locations to work out what happened to plants and animals as climate change and human intrusion transformed the world’s forests. Again, the answers are not simple.

No guarantee

“Surprisingly, we found that forest loss doesn’t always lead to biodiversity declines,” said Gergana Daskalova of the University of Edinburgh in Scotland. “Instead, when we lose forest cover, this can amplify the ongoing biodiversity change. For example, if a plant or animal species was declining before forest loss, its decline becomes even more severe.” Species already doing well, however, seemed to do better.

But there’s little guarantee that what works now will go on working, according to Arizona scientists writing in the journal Global Change Biology. So far, forests have helped contain climate change. But they found that North America’s most prolific tree, the Douglas fir, will absorb less carbon in future and do less to slow climate change.

They based their finding on examination of 2.7 million tree rings from 2,700 sites in the fir’s enormous ecological range. At the southern and warmest and driest end of this range, the decline in annual growth could be as high as 30%.

“More warming for trees could mean more stress, more tree death and less capacity to slow global warming,” said Margaret Evans, of the University of Arizona.

“Up until now, forests have stabilised the climate, but as they become more drought-stressed, they could become a destabilising carbon source.” − Climate News Network

World’s species numbers stay much the same

Life is on the move. Everywhere, the mix of creatures is changing for better and worse. The world’s species remain diverse. But for how long?

LONDON, 30 October, 2019 – Biodiversity – that vital mix of the world’s species, insects, worms, birds, mammals, fish, amphibians, microbes, plants and fungi that make up an ecosystem – is being reorganised. Change is happening almost everywhere on land and much faster in the seas that cover seven-tenths of the globe.

But when an international team of researchers looked at 239 studies that catalogued 50,000 changes in the living world over the decades, they arrived at a paradoxical puzzle.

The composition of an ecosystem is being altered, and altered sometimes at speed, by rising temperatures driven by human use of fossil fuels, by human colonisation of the grasslands, forests and wetlands, and by human disturbance of coral reefs, sea meadows, mangrove swamps and other submarine habitats.

But on average, the richness of life – the sheer numbers of species – in the world’s more closely studied ecosystems has remained much the same: that is, as some creatures or growths vanish from a cloud forest or an estuarine mudbank, the space they occupied is colonised by newcomers more comfortable with change.

Mixed picture

“Our study shows that biodiversity is changing everywhere, but we are not losing biodiversity everywhere. Some places are recovering and adapting,” says Maria Dornelas of the University of St Andrews in the UK.

“When biodiversity is in the news these days, it is often because the Amazon is on fire, or there is a global mass mortality event in coral reefs,  and rightly so, because this is terrifying news.

“However there is a lot of recovery taking place silently in the background, and many places where not much is happening. Our study puts these things on the map and shows they are not contradictory.”

The finding seems to question two decades of scientific orthodoxy: that because of human action, species are being extinguished at an accelerated rate. Extinction is a part of evolution, but biologists calculate that it is now happening at least a thousand times faster than the average rate for the past 500 million years.

“A sixth mass extinction could still be happening while local scale richness shows little change”

And humans are to blame for the “sixth mass extinction” which threatens perhaps a million species and is likely to be made worse by global heating and the climate emergency. Species are vanishing from ecosystems at the local level, and globally.

The latest study, in the journal Science, suggests that the big picture is more complicated: as environments change, so does the mix of local species. Some migrate, some adapt, some invade. Overall, the richness of the local population may not change a lot.

But this finding may not be inconsistent with global alarm about species loss on a massive scale as human numbers go on rising, and levels of greenhouse gas continue to soar. Change is happening faster in the tropics, those regions with the greatest variety of life. The dangers have not evaporated.

Philip Martin, an ecologist at the University of Cambridge, who was not involved in the research, tells Climate News Network that any finding that, on average, 28% of species were being replaced each decade should be a worry.

Excluding complacency

It might be that local species with narrow ranges were being replaced by more resilient plants or animals capable of surviving a much wider range of conditions: if so, the numbers of species in any local ecosystem might remain stable but the variety of life overall could still be diminished.

“As such, a sixth mass extinction could still be happening while local scale richness shows little change,” he warns.

And the paper’s authors make a parallel point: there is no case for complacency. “If these trends are maintained, this could lead to a dramatic restructuring of biodiversity, with potentially severe consequences for ecosystem functioning,” says Shane Blowes of the Centre for Integrative Biodiversity Research at Halle-Jena-Leipzig in Germany.

And Andrew Gonzalez of McGill University in Canada says: “The Earth is going through a great geographic reorganisation of its biodiversity in response to human activities and climate change. Given what we know it is likely this will continue for decades to come.” – Climate News Network

Life is on the move. Everywhere, the mix of creatures is changing for better and worse. The world’s species remain diverse. But for how long?

LONDON, 30 October, 2019 – Biodiversity – that vital mix of the world’s species, insects, worms, birds, mammals, fish, amphibians, microbes, plants and fungi that make up an ecosystem – is being reorganised. Change is happening almost everywhere on land and much faster in the seas that cover seven-tenths of the globe.

But when an international team of researchers looked at 239 studies that catalogued 50,000 changes in the living world over the decades, they arrived at a paradoxical puzzle.

The composition of an ecosystem is being altered, and altered sometimes at speed, by rising temperatures driven by human use of fossil fuels, by human colonisation of the grasslands, forests and wetlands, and by human disturbance of coral reefs, sea meadows, mangrove swamps and other submarine habitats.

But on average, the richness of life – the sheer numbers of species – in the world’s more closely studied ecosystems has remained much the same: that is, as some creatures or growths vanish from a cloud forest or an estuarine mudbank, the space they occupied is colonised by newcomers more comfortable with change.

Mixed picture

“Our study shows that biodiversity is changing everywhere, but we are not losing biodiversity everywhere. Some places are recovering and adapting,” says Maria Dornelas of the University of St Andrews in the UK.

“When biodiversity is in the news these days, it is often because the Amazon is on fire, or there is a global mass mortality event in coral reefs,  and rightly so, because this is terrifying news.

“However there is a lot of recovery taking place silently in the background, and many places where not much is happening. Our study puts these things on the map and shows they are not contradictory.”

The finding seems to question two decades of scientific orthodoxy: that because of human action, species are being extinguished at an accelerated rate. Extinction is a part of evolution, but biologists calculate that it is now happening at least a thousand times faster than the average rate for the past 500 million years.

“A sixth mass extinction could still be happening while local scale richness shows little change”

And humans are to blame for the “sixth mass extinction” which threatens perhaps a million species and is likely to be made worse by global heating and the climate emergency. Species are vanishing from ecosystems at the local level, and globally.

The latest study, in the journal Science, suggests that the big picture is more complicated: as environments change, so does the mix of local species. Some migrate, some adapt, some invade. Overall, the richness of the local population may not change a lot.

But this finding may not be inconsistent with global alarm about species loss on a massive scale as human numbers go on rising, and levels of greenhouse gas continue to soar. Change is happening faster in the tropics, those regions with the greatest variety of life. The dangers have not evaporated.

Philip Martin, an ecologist at the University of Cambridge, who was not involved in the research, tells Climate News Network that any finding that, on average, 28% of species were being replaced each decade should be a worry.

Excluding complacency

It might be that local species with narrow ranges were being replaced by more resilient plants or animals capable of surviving a much wider range of conditions: if so, the numbers of species in any local ecosystem might remain stable but the variety of life overall could still be diminished.

“As such, a sixth mass extinction could still be happening while local scale richness shows little change,” he warns.

And the paper’s authors make a parallel point: there is no case for complacency. “If these trends are maintained, this could lead to a dramatic restructuring of biodiversity, with potentially severe consequences for ecosystem functioning,” says Shane Blowes of the Centre for Integrative Biodiversity Research at Halle-Jena-Leipzig in Germany.

And Andrew Gonzalez of McGill University in Canada says: “The Earth is going through a great geographic reorganisation of its biodiversity in response to human activities and climate change. Given what we know it is likely this will continue for decades to come.” – Climate News Network

Climates change faster in a warmer and wetter world

While more rain normally cools a summer environment, a warmer and wetter world could face quite unfamiliar problems.

LONDON, 16 March, 2018 – Climate change may still cause surprises, if simultaneously it means a warmer and wetter world. More heat and moisture together can unbalance ecosystems.

Scientists have been warning for decades of shifts towards ever greater risks of flooding in some places, more intense and sustained droughts and potentially lethal heatwaves in others.

But new research suggests an unexpected twist: temperate and subtropical zones could become both hotter and wetter during future summers.

And this could create a whole suite of unexpected problems: farmers and city dwellers who have adapted to a pattern of cool wet summers or hot dry summers could face a new range of fungal or pest infections in crops, or pathogens in crowded communities, as insects and microbes seize a new set of opportunities.

“We found that where temperature and precipitation are increasing together, climates are changing faster than the temperature trend alone would suggest”

Canadian scientists report in Nature Communications that they considered what they call “departures from natural variability” that may follow as a consequence of continual rises in global average temperature, driven by ever greater combustion of fossil fuels that emit ever higher ratios of greenhouse gases into the atmosphere.

They studied historical records back to 1901, and climate projections as far as the year 2100. And they see a problem: creatures – people, crops, pathogens and pests – that have adapted to particular regional ecosystems could be jolted out of their comfort zone.

“Some of the disruptions of climate change stem from basic physics and are easily anticipated. Increases in sea level, forest fires, heat waves, and droughts fall into that category.

“But there is a whole other category of unexpected disruptions that stem from upsetting the complex balance of ecosystems,” said Colin Mahony, a forester and doctoral student at the University of British Columbia, who led the research.

A global increase in outbreaks of fungal needle blight in pine plantations could be linked to wetter and warmer conditions. Mosquito-borne pathogens could flourish in hot cities with once rare puddles of standing water.

Literature overload

“The mountain pine beetle epidemic that devastated the pine forests of western North America ten years ago is an example of this. This study digs into global climate model output for clues about what kinds of ecological disruptions might be just over the horizon,” he said.

The research points to the south-eastern US, central Canada, northern Australia, southern Africa, central Asia and the African Sahel as regions that could unexpectedly become warmer and wetter in ways that could disrupt normal patterns.

“We found that where temperature and precipitation are increasing together, climates are changing faster than the temperature trend alone would suggest,” he said.

The research was triggered, he told Climate News Network, by the Network’s report of a 2015 paper that predicted harder rainfall in a warmer world.

“The scientific literature on climate change is so vast that sites like the Climate News Network are an important way to bridge the barriers between researchers in different disciplines like ecology and atmospheric sciences.” – Climate News Network

While more rain normally cools a summer environment, a warmer and wetter world could face quite unfamiliar problems.

LONDON, 16 March, 2018 – Climate change may still cause surprises, if simultaneously it means a warmer and wetter world. More heat and moisture together can unbalance ecosystems.

Scientists have been warning for decades of shifts towards ever greater risks of flooding in some places, more intense and sustained droughts and potentially lethal heatwaves in others.

But new research suggests an unexpected twist: temperate and subtropical zones could become both hotter and wetter during future summers.

And this could create a whole suite of unexpected problems: farmers and city dwellers who have adapted to a pattern of cool wet summers or hot dry summers could face a new range of fungal or pest infections in crops, or pathogens in crowded communities, as insects and microbes seize a new set of opportunities.

“We found that where temperature and precipitation are increasing together, climates are changing faster than the temperature trend alone would suggest”

Canadian scientists report in Nature Communications that they considered what they call “departures from natural variability” that may follow as a consequence of continual rises in global average temperature, driven by ever greater combustion of fossil fuels that emit ever higher ratios of greenhouse gases into the atmosphere.

They studied historical records back to 1901, and climate projections as far as the year 2100. And they see a problem: creatures – people, crops, pathogens and pests – that have adapted to particular regional ecosystems could be jolted out of their comfort zone.

“Some of the disruptions of climate change stem from basic physics and are easily anticipated. Increases in sea level, forest fires, heat waves, and droughts fall into that category.

“But there is a whole other category of unexpected disruptions that stem from upsetting the complex balance of ecosystems,” said Colin Mahony, a forester and doctoral student at the University of British Columbia, who led the research.

A global increase in outbreaks of fungal needle blight in pine plantations could be linked to wetter and warmer conditions. Mosquito-borne pathogens could flourish in hot cities with once rare puddles of standing water.

Literature overload

“The mountain pine beetle epidemic that devastated the pine forests of western North America ten years ago is an example of this. This study digs into global climate model output for clues about what kinds of ecological disruptions might be just over the horizon,” he said.

The research points to the south-eastern US, central Canada, northern Australia, southern Africa, central Asia and the African Sahel as regions that could unexpectedly become warmer and wetter in ways that could disrupt normal patterns.

“We found that where temperature and precipitation are increasing together, climates are changing faster than the temperature trend alone would suggest,” he said.

The research was triggered, he told Climate News Network, by the Network’s report of a 2015 paper that predicted harder rainfall in a warmer world.

“The scientific literature on climate change is so vast that sites like the Climate News Network are an important way to bridge the barriers between researchers in different disciplines like ecology and atmospheric sciences.” – Climate News Network

By air, land and sea, global warming rises

Global warming took surface temperatures in 2017 to near-record levels, while the upper oceans reached their hottest known level.

LONDON, 19 January, 2018 – Global warming is real, and it’s happening now. Within hours of the announcement by scientists in the US that 2017 was at least the third warmest year recorded, if not the second, over the Earth’s land and oceans, there comes a further revelation: 2017 was also the warmest year on record for the global oceans.

Both disclosures are consistent with what scientists had expected from climate change, driven by global warming as a consequence of the profligate combustion of fossil fuels that dump ever greater levels of greenhouse gases in the atmosphere.

But they add to the scientists’ sense of urgency at the need for rapid and radical action to cut greenhouse emissions. Of the US announcement, Dr Dann Mitchell, of the University of Bristol, UK, said: “The most recent global temperature observations are in line with what we expected, both from our underlying theory, but also our model projections and understanding of the climate system.

“The atmosphere is warming, by almost 1°C globally to date, and we are getting ever closer to the Paris Agreement target of 1.5°C which we are so desperately trying to avoid.”

The news that the oceans are continuing to warm to hitherto unknown levels comes in an updated ocean analysis from the Institute of Atmospheric Physics/Chinese Academy of Science (IAP/CAS). Its study was published as an early online release in the journal Advances in Atmospheric Sciences.

“The biggest natural influence on the climate is being dwarfed by human activities – predominantly CO₂ emissions”

The authors say that in 2017 the oceans in the upper 2000-metre layer of water were warmer than the second warmest year, 2015, and above the 1981-2010 climatological reference period.

Thanks to their large heat capacity, the oceans absorb warming caused by human activities, and more than 90% of the Earth’s extra heat from global warming is absorbed by them.

The study says the global ocean heat content record robustly represents the signature of global warming, and is affected less by weather-related “noise” and climate variability such as El Niño and La Niña events.

The IAP says the last five years have been the five warmest years in the oceans, as the long-term warming trend driven by human activities continued unabated.

The rise in ocean heat in 2017 occurred in most regions of the world. Increases in ocean temperature cause the volume of seawater to expand, contributing to the global average sea level rise, which in 2017 amounted to 1.7 mm. Other consequences include a decline in ocean oxygen, the bleaching of coral reefs, and the melting of sea ice and ice shelves.

Discrepancy explained

The globally averaged temperature over land and ocean surfaces for 2017 was the third highest since record keeping began in 1880, according to NOAA scientists.

There is a slight difference in the figures for 2017’s temperature. NOAA says the globally averaged temperature for the year makes it the third hottest since record-keeping began in 1880, while NASA says in a separate analysis that 2017 was the second warmest on record, behind 2016.

This minor difference is explained by the different methods used by the two agencies to analyse global temperatures, they say, though they point out that over the long term their records agree closely.

Both agree that the five warmest years on record have all occurred since 2010. The UK Met Office and the World Meteorological Organisation (WMO) also listed 2017 among the top three warmest years on record.

One striking feature of the consensus on 2017’s place in the record books is less about what did happen, and more about what didn’t. Last year was the second or third hottest after 2016, and on a level with 2015, the data show.

No boost

But those two years were affected by El Niño, the periodic natural phenomenon in the Pacific, which helps to boost temperatures worldwide. 2017 was not an El Niño year.

If it had been, the researchers say, it would probably have been the warmest year yet, outstripping the heat in 2015 and 2016.

The acting director of the UK Met Office, Professor Peter Stott, told BBC News: “It’s extraordinary that temperatures in 2017 have been so high when there’s no El Niño. In fact, we’ve been going into cooler La Niña conditions.

“It shows clearly that the biggest natural influence on the climate is being dwarfed by human activities – predominantly CO₂ emissions.”

The WMO secretary-general, Petteri Taalas, said the long-term temperature trend was far more important than the ranking of individual years: “That trend is an upward one. Seventeen of the 18 warmest years on record have all been during this century, and the degree of warming during the past three years has been exceptional.

“Arctic warmth has been especially pronounced, and this will have profound and long-lasting repercussions on sea levels, and on weather patterns in other parts of the world.” – Climate News Network

Global warming took surface temperatures in 2017 to near-record levels, while the upper oceans reached their hottest known level.

LONDON, 19 January, 2018 – Global warming is real, and it’s happening now. Within hours of the announcement by scientists in the US that 2017 was at least the third warmest year recorded, if not the second, over the Earth’s land and oceans, there comes a further revelation: 2017 was also the warmest year on record for the global oceans.

Both disclosures are consistent with what scientists had expected from climate change, driven by global warming as a consequence of the profligate combustion of fossil fuels that dump ever greater levels of greenhouse gases in the atmosphere.

But they add to the scientists’ sense of urgency at the need for rapid and radical action to cut greenhouse emissions. Of the US announcement, Dr Dann Mitchell, of the University of Bristol, UK, said: “The most recent global temperature observations are in line with what we expected, both from our underlying theory, but also our model projections and understanding of the climate system.

“The atmosphere is warming, by almost 1°C globally to date, and we are getting ever closer to the Paris Agreement target of 1.5°C which we are so desperately trying to avoid.”

The news that the oceans are continuing to warm to hitherto unknown levels comes in an updated ocean analysis from the Institute of Atmospheric Physics/Chinese Academy of Science (IAP/CAS). Its study was published as an early online release in the journal Advances in Atmospheric Sciences.

“The biggest natural influence on the climate is being dwarfed by human activities – predominantly CO₂ emissions”

The authors say that in 2017 the oceans in the upper 2000-metre layer of water were warmer than the second warmest year, 2015, and above the 1981-2010 climatological reference period.

Thanks to their large heat capacity, the oceans absorb warming caused by human activities, and more than 90% of the Earth’s extra heat from global warming is absorbed by them.

The study says the global ocean heat content record robustly represents the signature of global warming, and is affected less by weather-related “noise” and climate variability such as El Niño and La Niña events.

The IAP says the last five years have been the five warmest years in the oceans, as the long-term warming trend driven by human activities continued unabated.

The rise in ocean heat in 2017 occurred in most regions of the world. Increases in ocean temperature cause the volume of seawater to expand, contributing to the global average sea level rise, which in 2017 amounted to 1.7 mm. Other consequences include a decline in ocean oxygen, the bleaching of coral reefs, and the melting of sea ice and ice shelves.

Discrepancy explained

The globally averaged temperature over land and ocean surfaces for 2017 was the third highest since record keeping began in 1880, according to NOAA scientists.

There is a slight difference in the figures for 2017’s temperature. NOAA says the globally averaged temperature for the year makes it the third hottest since record-keeping began in 1880, while NASA says in a separate analysis that 2017 was the second warmest on record, behind 2016.

This minor difference is explained by the different methods used by the two agencies to analyse global temperatures, they say, though they point out that over the long term their records agree closely.

Both agree that the five warmest years on record have all occurred since 2010. The UK Met Office and the World Meteorological Organisation (WMO) also listed 2017 among the top three warmest years on record.

One striking feature of the consensus on 2017’s place in the record books is less about what did happen, and more about what didn’t. Last year was the second or third hottest after 2016, and on a level with 2015, the data show.

No boost

But those two years were affected by El Niño, the periodic natural phenomenon in the Pacific, which helps to boost temperatures worldwide. 2017 was not an El Niño year.

If it had been, the researchers say, it would probably have been the warmest year yet, outstripping the heat in 2015 and 2016.

The acting director of the UK Met Office, Professor Peter Stott, told BBC News: “It’s extraordinary that temperatures in 2017 have been so high when there’s no El Niño. In fact, we’ve been going into cooler La Niña conditions.

“It shows clearly that the biggest natural influence on the climate is being dwarfed by human activities – predominantly CO₂ emissions.”

The WMO secretary-general, Petteri Taalas, said the long-term temperature trend was far more important than the ranking of individual years: “That trend is an upward one. Seventeen of the 18 warmest years on record have all been during this century, and the degree of warming during the past three years has been exceptional.

“Arctic warmth has been especially pronounced, and this will have profound and long-lasting repercussions on sea levels, and on weather patterns in other parts of the world.” – Climate News Network

Lizards help to explain climate impacts

Lizards can shed light on the development of ecological niches and how the changing climate may affect the natural world.

LONDON, 23 November, 2017 – US scientists think lizards could help them one step nearer to an old dream: a kind of “periodic table” for ecology.

Just as the great insight of the Russian chemist Dmitri Mendeleev now means that chemists can understand better the relationships between elements, and make predictions about their responses, a classification of ecological niches could help biologists better understand the impact of climate change on the millions of species that share the Earth.

Such a project may never be completed, but a new study in The American Naturalist demonstrates that it has begun.

An ecological niche is a tangle of environmental conditions and biological behaviours that mean an insect, an amphibian, a reptile, bird or mammal is specialised to make the best of its short life. For example, fig wasps need fig trees to survive, and if there are 900 species of fig tree on the planet, 900 species of fig wasp will evolve to fill those ecological niches.

The researchers worked out what constitutes a niche: they chose habitat, diet, life history, metabolism and defence, and then listed between seven and 15 variables for each of those properties. Then they compiled all the data they could find about 134 species of lizard on four continents from 24 of the planet’s 38 surviving lizard families. And then they started to impose order on their material.

“Summarising major ecological traits in such simple schemes will allow ecologists to predict how species might react to new environmental conditions”

They could do that because, even though Australian desert lizards are of entirely separate species from desert lizards in Africa, or America, they forage for food, stay lively or dormant at given times, reproduce and exploit their habitat in very similar ways. Evolutionary pressures mean that they have converged to fill similar ecological niches.

“Summarising major ecological traits in such simple schemes will allow ecologists to predict how species might react to new environmental conditions and the invasive potential of species,” said Eric Pianka, a zoologist at the University of Texas at Austin, who led the study. 

“It will inform us about how niches have evolved in the past and even how they will evolve in the future, all of which has direct bearing on impacts of climate change.”

Climate change presents biologists with a problem: humans depend on the natural world in myriad ways; plant, fungus and animal species recycle the world’s air and water, conserve rainfall, pollinate crops, generate fruits and seeds for nourishment and chemicals for pharmaceuticals, fabrics for clothes and shelter.

They dispose of excrement and other biological waste, and each species in this intricate economy survives because it occupies an ecological niche.

Global risk

But the ecosystems that support such helpful networks are everywhere at risk because of climate change.  They are at hazard on a global scale and at the level of single nations or marine environments.

But without an intellectual framework that identifies the features that ecosystems, and ecological niches within those ecosystems, might have in common, conservation biologists won’t know where best to start.

What they do know is that conservation is vital, and that the creatures of the world are stronger because they are so many and so varied: yet another study from Switzerland involving 2,200 species in 450 different landscapes has just confirmed once again that the richer the variety of life in it, the more productive the landscape, and the better it is able to withstand change.

Now the scientists from Texas, Oklahoma and Argentina have confirmed, with what they call “the lizard niche hypervolume”, the possibility of a living equivalent of the periodic table that permits predictions that could be confirmed by observation or experiment, not just for lizards but for other families.

Separate niches

Lizards, like birds, inhabit trees, lay eggs and devour insects: unlike birds, they rely on the environment to maintain their temperature, so what would be one day’s food for a small bird might keep a lizard alive for a month.

It follows that birds and lizards occupy separate ecological niches. Ecologists have a potential structure or scaffolding into which to place their specimen animal and its ideal habitat and consider it in relation to other ecological niches.

But, as the researchers point out, so far only 2.2% of known lizards are included in their analysis, and environments are dynamic things: they change with time. There is a lot more to be done in researching clades, groupings of organisms which share a common ancestor and all of its descendants.

“As more periodic tables are created,” they write, “comparative analyses among more distantly-related clades (fish-frogs-salamanders-lizards-snakes-birds-mammals) will become possible, ultimately leading to a wider understanding of niche evolution among vertebrates.” – Climate News Network

Lizards can shed light on the development of ecological niches and how the changing climate may affect the natural world.

LONDON, 23 November, 2017 – US scientists think lizards could help them one step nearer to an old dream: a kind of “periodic table” for ecology.

Just as the great insight of the Russian chemist Dmitri Mendeleev now means that chemists can understand better the relationships between elements, and make predictions about their responses, a classification of ecological niches could help biologists better understand the impact of climate change on the millions of species that share the Earth.

Such a project may never be completed, but a new study in The American Naturalist demonstrates that it has begun.

An ecological niche is a tangle of environmental conditions and biological behaviours that mean an insect, an amphibian, a reptile, bird or mammal is specialised to make the best of its short life. For example, fig wasps need fig trees to survive, and if there are 900 species of fig tree on the planet, 900 species of fig wasp will evolve to fill those ecological niches.

The researchers worked out what constitutes a niche: they chose habitat, diet, life history, metabolism and defence, and then listed between seven and 15 variables for each of those properties. Then they compiled all the data they could find about 134 species of lizard on four continents from 24 of the planet’s 38 surviving lizard families. And then they started to impose order on their material.

“Summarising major ecological traits in such simple schemes will allow ecologists to predict how species might react to new environmental conditions”

They could do that because, even though Australian desert lizards are of entirely separate species from desert lizards in Africa, or America, they forage for food, stay lively or dormant at given times, reproduce and exploit their habitat in very similar ways. Evolutionary pressures mean that they have converged to fill similar ecological niches.

“Summarising major ecological traits in such simple schemes will allow ecologists to predict how species might react to new environmental conditions and the invasive potential of species,” said Eric Pianka, a zoologist at the University of Texas at Austin, who led the study. 

“It will inform us about how niches have evolved in the past and even how they will evolve in the future, all of which has direct bearing on impacts of climate change.”

Climate change presents biologists with a problem: humans depend on the natural world in myriad ways; plant, fungus and animal species recycle the world’s air and water, conserve rainfall, pollinate crops, generate fruits and seeds for nourishment and chemicals for pharmaceuticals, fabrics for clothes and shelter.

They dispose of excrement and other biological waste, and each species in this intricate economy survives because it occupies an ecological niche.

Global risk

But the ecosystems that support such helpful networks are everywhere at risk because of climate change.  They are at hazard on a global scale and at the level of single nations or marine environments.

But without an intellectual framework that identifies the features that ecosystems, and ecological niches within those ecosystems, might have in common, conservation biologists won’t know where best to start.

What they do know is that conservation is vital, and that the creatures of the world are stronger because they are so many and so varied: yet another study from Switzerland involving 2,200 species in 450 different landscapes has just confirmed once again that the richer the variety of life in it, the more productive the landscape, and the better it is able to withstand change.

Now the scientists from Texas, Oklahoma and Argentina have confirmed, with what they call “the lizard niche hypervolume”, the possibility of a living equivalent of the periodic table that permits predictions that could be confirmed by observation or experiment, not just for lizards but for other families.

Separate niches

Lizards, like birds, inhabit trees, lay eggs and devour insects: unlike birds, they rely on the environment to maintain their temperature, so what would be one day’s food for a small bird might keep a lizard alive for a month.

It follows that birds and lizards occupy separate ecological niches. Ecologists have a potential structure or scaffolding into which to place their specimen animal and its ideal habitat and consider it in relation to other ecological niches.

But, as the researchers point out, so far only 2.2% of known lizards are included in their analysis, and environments are dynamic things: they change with time. There is a lot more to be done in researching clades, groupings of organisms which share a common ancestor and all of its descendants.

“As more periodic tables are created,” they write, “comparative analyses among more distantly-related clades (fish-frogs-salamanders-lizards-snakes-birds-mammals) will become possible, ultimately leading to a wider understanding of niche evolution among vertebrates.” – Climate News Network

Climate change may increase California’s rain

In a warmer world California’s rain may be more ample than today. But so far most climate scientists foresee more drought.

LONDON, 8 July, 2017 – If humans go on burning fossil fuels, then California might, after all, remain the Golden State. It will get warmer. But, against all predictions, it might also get wetter.

A new study suggests that by the century’s end, Californians could see 12% more rain than they experienced in the last 20 years of the 20th century.

This is not the standard forecast. Almost all other climate models have warned that California – still recovering from a calamitous and sustained drought – could, like the whole of the US Southwest, become both hotter and drier and far more at risk of wildfire.

But that is not how two researchers see it. They report in the journal Nature Communications that although, under the notorious “business-as-usual” scenario, in which people go on filling cars with petrol and generating electricity by burning coal, the most southern tip of the state would indeed continue to parch, rain in northern California could increase by 14.1% and central California by 15.2%.

“The overall thought was California would become drier with continued climate change. We found the opposite, which is quite surprising”

The latest predictions are based – like all other previous analyses – on computer simulations of future climate, and, like all simulations, they depend on the data available to the modellers.

But overall, forecasts for California have repeatedly suggested that the state could be in for a run of very dry seasons, especially as falling winter precipitation would mean that the state could hardly rely on melting snow to deliver the irrigation for the orange groves, vineyards and market gardens.

But the latest researchers found that rain and snow in December, January and February – which has usually  been when the heavens opened for California – would actually increase: more than 39% in central California, 31.6% in the north, and 10.6% in the south, in comparison with averages from the years 1979 to 1999.

“Most previous research emphasised uncertainty with regards to future precipitation levels in California, but the overall thought was California would become drier with continued climate change,” said Robert Allen, of the University of California Riverside, one of the authors. “We found the opposite, which is quite surprising.”

Surprises

This is not the first contrary finding recently produced by climate modellers. Although, overall, climate scientists expect the already arid zones to become more arid, and the well-watered regions to get even more rain, climate change could deliver surprises.

One research team has just predicted the arrival of seasonal monsoons for the Sahel region of northern Africa, historically prone to drought. 

The Sahel forecasters and the Californian modellers linked their higher rainfall to shifts in ocean temperature. As the tropical eastern Pacific Ocean warms, there could be a shift in the jet stream to the southeast, which could bring more rain-producing cyclones over California.

“Essentially, this mechanism is similar to what we in California expect during an El Niño year,” Dr Allen said. “Ultimately, what I am arguing is El Niño-like years are going to become more the norm in California.” – Climate News Network 

In a warmer world California’s rain may be more ample than today. But so far most climate scientists foresee more drought.

LONDON, 8 July, 2017 – If humans go on burning fossil fuels, then California might, after all, remain the Golden State. It will get warmer. But, against all predictions, it might also get wetter.

A new study suggests that by the century’s end, Californians could see 12% more rain than they experienced in the last 20 years of the 20th century.

This is not the standard forecast. Almost all other climate models have warned that California – still recovering from a calamitous and sustained drought – could, like the whole of the US Southwest, become both hotter and drier and far more at risk of wildfire.

But that is not how two researchers see it. They report in the journal Nature Communications that although, under the notorious “business-as-usual” scenario, in which people go on filling cars with petrol and generating electricity by burning coal, the most southern tip of the state would indeed continue to parch, rain in northern California could increase by 14.1% and central California by 15.2%.

“The overall thought was California would become drier with continued climate change. We found the opposite, which is quite surprising”

The latest predictions are based – like all other previous analyses – on computer simulations of future climate, and, like all simulations, they depend on the data available to the modellers.

But overall, forecasts for California have repeatedly suggested that the state could be in for a run of very dry seasons, especially as falling winter precipitation would mean that the state could hardly rely on melting snow to deliver the irrigation for the orange groves, vineyards and market gardens.

But the latest researchers found that rain and snow in December, January and February – which has usually  been when the heavens opened for California – would actually increase: more than 39% in central California, 31.6% in the north, and 10.6% in the south, in comparison with averages from the years 1979 to 1999.

“Most previous research emphasised uncertainty with regards to future precipitation levels in California, but the overall thought was California would become drier with continued climate change,” said Robert Allen, of the University of California Riverside, one of the authors. “We found the opposite, which is quite surprising.”

Surprises

This is not the first contrary finding recently produced by climate modellers. Although, overall, climate scientists expect the already arid zones to become more arid, and the well-watered regions to get even more rain, climate change could deliver surprises.

One research team has just predicted the arrival of seasonal monsoons for the Sahel region of northern Africa, historically prone to drought. 

The Sahel forecasters and the Californian modellers linked their higher rainfall to shifts in ocean temperature. As the tropical eastern Pacific Ocean warms, there could be a shift in the jet stream to the southeast, which could bring more rain-producing cyclones over California.

“Essentially, this mechanism is similar to what we in California expect during an El Niño year,” Dr Allen said. “Ultimately, what I am arguing is El Niño-like years are going to become more the norm in California.” – Climate News Network 

Polar sea ice reaches record low

Arctic sea ice polar

NASA scientists say that in the last six months the world has lost an area of polar sea ice that is bigger than Mexico.

LONDON, 30 March, 2017 Arctic sea ice in March reached a new record low: the area of frozen ocean at the height of winter on 7 March reached a new maximum low for the third year running, according to NASA scientists. Only a few days earlier, on 3 March, Antarctic sea ice reached its own new record summer low since satellite observations began in 1979.

And on 13 February the total area of frozen ocean in the two hemispheres was at its lowest: 16.21 million square kilometres, which is about 2m sq km less than the average global minimum for 1981 to 2010.

In effect, the NASA scientists report, the world had lost a chunk of sea ice of an area bigger than Mexico.

Extraordinary conditions

It has been quite extraordinary for several months in the Arctic,” says Julienne Stroeve, professor of polar observation at University College London. “Pretty much all through October, November, December, January, February and now March, we have been tracking record low conditions. I don’t think there has ever been a time in the Arctic when we have seen so many months of just record consecutive low conditions.”

The most dramatic losses of sea ice have over the decades been observed in summer – where the decline has been measured at 14% per decade. Winter shrinkage has been at a much lower rate: about 3% per decade. But the ice has been thinning as well as dwindling in area, and temperatures earlier in the winter were unusually high: 20°C above the average for the time of the year.

Nobody can be sure what will happen once the spring thaw has begun, but polar scientists are expecting the worst. “We are pretty much poised to have really low summer ice conditions,” Professor Stroeve says.

We have been at record low levels. There is a lot
of year-to-year variability, and it was only
a couple of years ago we saw a maximum”

The frozen ocean around the Antarctic continent, too, has scientists worried. Sea ice fell to 2.11m sq km on 3 March. This is below the previous lowest minimum on record, exactly 20 years ago.

The two poles are very different. The Arctic is an ocean surrounded by land, while the Antarctic is a vast continent ringed by ocean, therefore the dynamics of ice formation and loss are not the same. And in recent years, the extent of sea ice in Antarctica had been growing. But this March, at the close of the Antarctic summer, there was a dramatic change.

It is tempting to say that the record low we are seeing is global warming finally catching up with Antarctica,” says Walt Meier of NASA’s Goddard Space Flight Centre in Maryland.

However, this might just be an extreme case of pushing the envelope of year-to-year variability. We’ll need to have several more years of data to be able to say there has been a significant change in the trend.”

Both polar regions are affected by natural variation. But the suspicion is that the long-term trend in global warming driven by human combustion of fossil fuels that dump vast quantities of greenhouse gases into the atmosphere must be playing a part. One research group recently proposed that human action might be responsible for at least half and perhaps 70% of Arctic warming.

Polar variability

Southern polar sea ice reached its peak at the end of August, and November, December, January and February all saw rapid declines.

We have been at record low levels,” says Emily Shuckburgh, deputy head of polar oceans at the British Antarctic Survey. “There is a lot of year-to-year variability, and it was only a couple of years ago we saw a maximum.

This is just one year where there is a lot of variability, and really understanding what the implications are is the research challenge.” Climate News Network

NASA scientists say that in the last six months the world has lost an area of polar sea ice that is bigger than Mexico.

LONDON, 30 March, 2017 Arctic sea ice in March reached a new record low: the area of frozen ocean at the height of winter on 7 March reached a new maximum low for the third year running, according to NASA scientists. Only a few days earlier, on 3 March, Antarctic sea ice reached its own new record summer low since satellite observations began in 1979.

And on 13 February the total area of frozen ocean in the two hemispheres was at its lowest: 16.21 million square kilometres, which is about 2m sq km less than the average global minimum for 1981 to 2010.

In effect, the NASA scientists report, the world had lost a chunk of sea ice of an area bigger than Mexico.

Extraordinary conditions

It has been quite extraordinary for several months in the Arctic,” says Julienne Stroeve, professor of polar observation at University College London. “Pretty much all through October, November, December, January, February and now March, we have been tracking record low conditions. I don’t think there has ever been a time in the Arctic when we have seen so many months of just record consecutive low conditions.”

The most dramatic losses of sea ice have over the decades been observed in summer – where the decline has been measured at 14% per decade. Winter shrinkage has been at a much lower rate: about 3% per decade. But the ice has been thinning as well as dwindling in area, and temperatures earlier in the winter were unusually high: 20°C above the average for the time of the year.

Nobody can be sure what will happen once the spring thaw has begun, but polar scientists are expecting the worst. “We are pretty much poised to have really low summer ice conditions,” Professor Stroeve says.

We have been at record low levels. There is a lot
of year-to-year variability, and it was only
a couple of years ago we saw a maximum”

The frozen ocean around the Antarctic continent, too, has scientists worried. Sea ice fell to 2.11m sq km on 3 March. This is below the previous lowest minimum on record, exactly 20 years ago.

The two poles are very different. The Arctic is an ocean surrounded by land, while the Antarctic is a vast continent ringed by ocean, therefore the dynamics of ice formation and loss are not the same. And in recent years, the extent of sea ice in Antarctica had been growing. But this March, at the close of the Antarctic summer, there was a dramatic change.

It is tempting to say that the record low we are seeing is global warming finally catching up with Antarctica,” says Walt Meier of NASA’s Goddard Space Flight Centre in Maryland.

However, this might just be an extreme case of pushing the envelope of year-to-year variability. We’ll need to have several more years of data to be able to say there has been a significant change in the trend.”

Both polar regions are affected by natural variation. But the suspicion is that the long-term trend in global warming driven by human combustion of fossil fuels that dump vast quantities of greenhouse gases into the atmosphere must be playing a part. One research group recently proposed that human action might be responsible for at least half and perhaps 70% of Arctic warming.

Polar variability

Southern polar sea ice reached its peak at the end of August, and November, December, January and February all saw rapid declines.

We have been at record low levels,” says Emily Shuckburgh, deputy head of polar oceans at the British Antarctic Survey. “There is a lot of year-to-year variability, and it was only a couple of years ago we saw a maximum.

This is just one year where there is a lot of variability, and really understanding what the implications are is the research challenge.” Climate News Network

Warming’s mixed effects on migratory animals

Global warming brent geese

New studies on beluga whales and Brent geese reveal that they respond to global warming in conflicting ways, making species survival hard to predict.

LONDON, 13 January, 2017 Beluga whales are responding to climate change in a rapidly warming Arctic – but only some of them. And migratory geese ought to be flourishing with milder conditions at nesting grounds in the far north – but the mother geese are at greater risk.

Both studies leave biologists guessing a bit at the response of their animal subjects to climate change. But the evidence shows that even the animals themselves may have to take a guess.

Warming Arctic

US scientists report in Global Change Biology that one population of beluga whales is taking advantage of the longer summers in the far north, while another is keeping to a calendar that pre-dates climate change.

Beluga whales, those ghostly white hunters of the northern seas, tend to winter in the Bering Sea between two continents, and then swim north as the ice melts and the Arctic seas open up.

The two populations of whales are genetically distinct – they have different ancestries – and travel as family groups, the young learning from their mothers.

Those that feed on fish and molluscs in the Beaufort Sea north of Alaska and Canada tend to leave the summer feeding grounds in autumn with the first risk of freezing. Those that hunt in the Chukchi Sea to the north and east of Alaska are delaying their response to take advantage of the longer spells of open water.

Summer sea ice has been in retreat for the last 30 years, and last autumn was an astonishing 20°C above average.

So biologists are confronted with a big question: is one population guarding against being caught by a sudden build-up of Arctic ice, while the other is consciously taking a risk but benefiting from a longer spell in richer feeding grounds?

The biggest take-home message is that belugas can respond relatively quickly to their changing environment, yet we can’t expect a uniform response across all beluga populations,” says Donna Hauser, of the University of Washington’s polar science centre in the US, who led the research.

If were trying to understand how these species are going to respond to climate change, we should expect to see variability in the response across populations and across time. That may complicate our predictions for the future.”

The polar puzzle is nothing new for biologists: creatures that migrate to the Arctic have always experienced a mix of good and bad summers.

Research like this is important because
we have to understand how animal populations
will respond to the changing climate if we want
to make decisions about protecting biodiversity”

Some Arctic predators, such as the polar bear, which depends on sea ice for a living, are imperilled by the early thaw and the late freeze. Other predators and herbivores can shift to new territories, or gain from changing climate one year and lose the next.

But as ecosystems shift dramatically in response to global warming, the tally of winners and losers becomes harder to predict.

The light-bellied Brent geese that breed each summer in northeast Canada could become a textbook example, according to a new study in the Journal of Animal Ecology.

Climate change means that nesting mothers breed more successfully in longer, warmer summers. But the latest study suggests that the same high productivity is accompanied by a higher death rate among mothers. That could be because the birds nest on the ground, stay longer in better conditions and become more vulnerable to predators.

In a bad breeding season, mothers abandon nests or do not breed – but they do survive to try again another year.

Climate change

We tend to think of climate change as being all one way, but here we’ve got a population being affected in conflicting ways,” says Ian Cleasby, of the Centre for Ecology and Conservation at the University of Exeter in the UK.

This population is sensitive to changes in adult survival, so the increased breeding may not be enough to offset the loss of more adult females.

Research like this is important because we have to understand how animal populations will respond to the changing climate if we want to make decisions about protecting biodiversity.” Climate News Network

New studies on beluga whales and Brent geese reveal that they respond to global warming in conflicting ways, making species survival hard to predict.

LONDON, 13 January, 2017 Beluga whales are responding to climate change in a rapidly warming Arctic – but only some of them. And migratory geese ought to be flourishing with milder conditions at nesting grounds in the far north – but the mother geese are at greater risk.

Both studies leave biologists guessing a bit at the response of their animal subjects to climate change. But the evidence shows that even the animals themselves may have to take a guess.

Warming Arctic

US scientists report in Global Change Biology that one population of beluga whales is taking advantage of the longer summers in the far north, while another is keeping to a calendar that pre-dates climate change.

Beluga whales, those ghostly white hunters of the northern seas, tend to winter in the Bering Sea between two continents, and then swim north as the ice melts and the Arctic seas open up.

The two populations of whales are genetically distinct – they have different ancestries – and travel as family groups, the young learning from their mothers.

Those that feed on fish and molluscs in the Beaufort Sea north of Alaska and Canada tend to leave the summer feeding grounds in autumn with the first risk of freezing. Those that hunt in the Chukchi Sea to the north and east of Alaska are delaying their response to take advantage of the longer spells of open water.

Summer sea ice has been in retreat for the last 30 years, and last autumn was an astonishing 20°C above average.

So biologists are confronted with a big question: is one population guarding against being caught by a sudden build-up of Arctic ice, while the other is consciously taking a risk but benefiting from a longer spell in richer feeding grounds?

The biggest take-home message is that belugas can respond relatively quickly to their changing environment, yet we can’t expect a uniform response across all beluga populations,” says Donna Hauser, of the University of Washington’s polar science centre in the US, who led the research.

If were trying to understand how these species are going to respond to climate change, we should expect to see variability in the response across populations and across time. That may complicate our predictions for the future.”

The polar puzzle is nothing new for biologists: creatures that migrate to the Arctic have always experienced a mix of good and bad summers.

Research like this is important because
we have to understand how animal populations
will respond to the changing climate if we want
to make decisions about protecting biodiversity”

Some Arctic predators, such as the polar bear, which depends on sea ice for a living, are imperilled by the early thaw and the late freeze. Other predators and herbivores can shift to new territories, or gain from changing climate one year and lose the next.

But as ecosystems shift dramatically in response to global warming, the tally of winners and losers becomes harder to predict.

The light-bellied Brent geese that breed each summer in northeast Canada could become a textbook example, according to a new study in the Journal of Animal Ecology.

Climate change means that nesting mothers breed more successfully in longer, warmer summers. But the latest study suggests that the same high productivity is accompanied by a higher death rate among mothers. That could be because the birds nest on the ground, stay longer in better conditions and become more vulnerable to predators.

In a bad breeding season, mothers abandon nests or do not breed – but they do survive to try again another year.

Climate change

We tend to think of climate change as being all one way, but here we’ve got a population being affected in conflicting ways,” says Ian Cleasby, of the Centre for Ecology and Conservation at the University of Exeter in the UK.

This population is sensitive to changes in adult survival, so the increased breeding may not be enough to offset the loss of more adult females.

Research like this is important because we have to understand how animal populations will respond to the changing climate if we want to make decisions about protecting biodiversity.” Climate News Network

Africa’s dust is a priceless export

dust storm

Scientists show how different the world would be without a sprinkling of the wind-borne African dust that fertilises oceans and forests.

LONDON, 3 December, 2016 − Climate scientists have identified Africa’s single biggest export – the wind-borne dust that fertilises the Amazon forests, nourishes life in the Atlantic ocean and softens the noonday blaze of the sun. And they have calculated its vital role in climate change over the last 23,000 years.

In the words of US oceanographers and Earth scientists, “North Africa exports teragrams of wind-blown mineral aerosol over the tropical North Atlantic each year, with significant climate and biogeochemical impacts.”

A teragram is a million tonnes, and the quantities airlifted into the sky from the Sahara and the Sahel each year by the trade winds and blown abroad would be enough to fill 10 million heavy trucks.

About 11,000 years ago, the continent’s total exports of fine dust began to fall dramatically, the researchers report in Science Advances journal.

Fine particles

The lower levels of fine particles in the sky may have allowed more sunlight to hit the ocean waters, may have warmed surface temperatures by 0.15°C, and may have helped whip up monsoons over North Africa to make the conditions far more temperate than they are today.

“In the tropical ocean, fractions of a degree can cause big differences in precipitation patterns and winds,” says one of the report’s authors, David McGee, assistant professor of paleoclimate and geochronology at the Massachusetts Institute of Technology.

“It does seem like dust variations may have large enough effects that it’s important to know how big those impacts are on past and future climates.”

Researchers have already established the importance of windblown dust, both as a source of mineral nutrient for marine life and for the rainforests of Brazil. Scientists have even identified dust kicked into the air by heavy rain.

“We need to figure out how big those dust impacts are, to understand both past and future climates”

But the latest study focused on the changing pattern of dust delivery from the peak of the last Ice Age to the present, the role it may have played in bygone climate change, and its importance in the human story.

North Africa was once a more temperate and hospitable place. Dr McGee says: “There was also extensive human settlement throughout the Sahara, with lifestyles that would never be possible today.

“Researchers at archaeological sites have found fish hooks and spears in the middle of the Sahara, in places that would be completely uninhabitable today. So there was clearly much more water and precipitation over the Sahara.”

Some of this may be explained by subtle cyclic shifts in the planetary axis, exposing the northern hemisphere to more sunlight, more evaporation and more rainfall over land.

Dust sediments

But climate models suggest that this might not be enough, so the researchers examined dust sediments deposited in the Bahamas over the last 23,000 years to identify the role of dust.

Towards the end of the last Ice Age, 16,000 years ago, African dust exports were twice what they are today. But between 11,000 and 5,000 years ago, Africa exported only about half the dust it airlifts now.

The implication is that wind-blown dust is an important factor in climate science, and even small changes in sea surface temperatures – of the sort that could be attributed to dusty skies – can have big effects on Atlantic winds and African rainfall.

“We’re not saying, the expansion of monsoon rains into the Sahara was caused solely by dust impacts,” Dr McGee says. “We’re saying we need to figure out how big those dust impacts are, to understand both past and future climates.” – Climate News Network

Scientists show how different the world would be without a sprinkling of the wind-borne African dust that fertilises oceans and forests.

LONDON, 3 December, 2016 − Climate scientists have identified Africa’s single biggest export – the wind-borne dust that fertilises the Amazon forests, nourishes life in the Atlantic ocean and softens the noonday blaze of the sun. And they have calculated its vital role in climate change over the last 23,000 years.

In the words of US oceanographers and Earth scientists, “North Africa exports teragrams of wind-blown mineral aerosol over the tropical North Atlantic each year, with significant climate and biogeochemical impacts.”

A teragram is a million tonnes, and the quantities airlifted into the sky from the Sahara and the Sahel each year by the trade winds and blown abroad would be enough to fill 10 million heavy trucks.

About 11,000 years ago, the continent’s total exports of fine dust began to fall dramatically, the researchers report in Science Advances journal.

Fine particles

The lower levels of fine particles in the sky may have allowed more sunlight to hit the ocean waters, may have warmed surface temperatures by 0.15°C, and may have helped whip up monsoons over North Africa to make the conditions far more temperate than they are today.

“In the tropical ocean, fractions of a degree can cause big differences in precipitation patterns and winds,” says one of the report’s authors, David McGee, assistant professor of paleoclimate and geochronology at the Massachusetts Institute of Technology.

“It does seem like dust variations may have large enough effects that it’s important to know how big those impacts are on past and future climates.”

Researchers have already established the importance of windblown dust, both as a source of mineral nutrient for marine life and for the rainforests of Brazil. Scientists have even identified dust kicked into the air by heavy rain.

“We need to figure out how big those dust impacts are, to understand both past and future climates”

But the latest study focused on the changing pattern of dust delivery from the peak of the last Ice Age to the present, the role it may have played in bygone climate change, and its importance in the human story.

North Africa was once a more temperate and hospitable place. Dr McGee says: “There was also extensive human settlement throughout the Sahara, with lifestyles that would never be possible today.

“Researchers at archaeological sites have found fish hooks and spears in the middle of the Sahara, in places that would be completely uninhabitable today. So there was clearly much more water and precipitation over the Sahara.”

Some of this may be explained by subtle cyclic shifts in the planetary axis, exposing the northern hemisphere to more sunlight, more evaporation and more rainfall over land.

Dust sediments

But climate models suggest that this might not be enough, so the researchers examined dust sediments deposited in the Bahamas over the last 23,000 years to identify the role of dust.

Towards the end of the last Ice Age, 16,000 years ago, African dust exports were twice what they are today. But between 11,000 and 5,000 years ago, Africa exported only about half the dust it airlifts now.

The implication is that wind-blown dust is an important factor in climate science, and even small changes in sea surface temperatures – of the sort that could be attributed to dusty skies – can have big effects on Atlantic winds and African rainfall.

“We’re not saying, the expansion of monsoon rains into the Sahara was caused solely by dust impacts,” Dr McGee says. “We’re saying we need to figure out how big those dust impacts are, to understand both past and future climates.” – Climate News Network