Tag Archives: Temperature rise

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

Ocean sensitivity may lower carbon emissions cuts

Ocean sensitivity to atmospheric change is well established. But just how sensitive the oceans are remains a surprise to science.

LONDON, 30 June, 2020 – As greenhouse gas emissions soar, ocean sensitivity has quietly helped humanity to slow global heating: the seas have responded by absorbing more and more carbon dioxide from the atmosphere.

But should humans come to grips with the challenge of looming climate catastrophe and start to reduce emissions, the oceans could respond again – by absorbing less and slightly slowing the fall of the mercury in the global thermometer.

And there is even an immediate chance to test this proposal: if so, then oceans that have been each year absorbing more and more carbon from the atmosphere as greenhouse gas ratios rise will go into brief reverse, because of the global economic shutdown and fall in emissions triggered by the global pandemic of Covid-19.

For the first time in decades, the oceans could take up less carbon dioxide in 2020, according to a new study by US scientists in the American Geophysical Union journal AGU Advances.

“We didn’t realise until we did this work that these external forcings, like changes in the growth of atmospheric carbon dioxide, dominate the variability in the global ocean on year-to-year timescales. That’s a real surprise,” said Galen McKinley, of Columbia University’s Lamont-Doherty Earth Observatory.

Feedback in action

“As we reduce our emissions and the growth rate of atmospheric carbon dioxide slows down, it’s important to realise that the ocean carbon sink will respond by slowing down.”

The research should not be interpreted as an invitation to go on burning fossil fuels. It is another lesson in the intricacy of the traffic between atmosphere, rocks, oceans, and living things in an evolving world. And it is more immediately an exquisite example of what engineers call feedback.

In cases of negative feedback, the agency of change also triggers a way of slowing that change. Since 1750 – the birth of the Industrial Revolution – human economies have added 440 billion tonnes of carbon to the planetary atmosphere.

For most of human history carbon dioxide ratios in the atmosphere had hovered around 285 parts per million. They have now gone beyond 400 ppm, and global average temperatures have already risen by more than 1°C.

They’d be even higher but for the oceans, which have responded by absorbing around 39% of all that extra carbon from coal, oil and gas combustion. So the oceans are sensitive to atmospheric change, and respond.

“There will be a time when the ocean will limit the effectiveness of mitigation actions, and this should be accounted for in policymaking”

The latest study is a lesson in how sensitive: Professor McKinley and her colleagues used computer models to try to understand better why the ocean uptake of carbon varies.

In the early 1990s, the ocean absorption of carbon dioxide varied: dramatically at first, because a devastating volcanic eruption of Mt Pinatubo in the Philippines in 1991 that darkened the stratosphere also accelerated ocean uptake.

And then the ocean uptake started to slow, as the skies cleared but also as the collapse of the Soviet Union and its satellite nations changed the global pattern of fuel use. It went on declining until 2001, when fossil fuel use started to accelerate. And then the ocean sink started once again to become more absorbent.

Such research is a reminder of how much scientists still don’t know about the machinery of the planet. That greenhouse gas from fossil fuel combustion drives global heating is not now in doubt. But the precise speed, and the drivers and brakes of positive and negative feedback, remain less certain.

Many feedbacks are positive: as the Arctic warms, carbon plant remains frozen in the permafrost will start to decay, release more methane and carbon dioxide, and accelerate warming.

Forest concern

As the sea ice retreats, and the ice reflects less sunlight, the exposed blue seas will absorb ever more radiation, to turn up the planetary temperatures. A warner world will be a wetter one, which may also mean a rise in the rate of warming.

But the ocean is not the only example of negative feedback. More carbon dioxide seems to mean more vigorous plant growth, and there is clear evidence that the world’s great forests are an important carbon sink: an example of negative feedback. That is why almost all governments recognise the importance of forest conservation.

Action however is uneven, forests are still being degraded, and there is alarming evidence that at some point, as temperatures get too high, the tropical forests could start surrendering the carbon they have for millennia absorbed, and become agents of positive feedback.

Professor McKinley warns that – as global emissions are cut – there will be a phase during which ocean uptake slows. If so, then planetary temperature rise will not slow as fast as hoped: extra carbon dioxide will linger, to contribute to warming.

“We need to discuss this coming feedback. We want people to understand that there will be a time when the ocean will limit the effectiveness of mitigation actions, and this should also be accounted for in policymaking.” – Climate News Network

Ocean sensitivity to atmospheric change is well established. But just how sensitive the oceans are remains a surprise to science.

LONDON, 30 June, 2020 – As greenhouse gas emissions soar, ocean sensitivity has quietly helped humanity to slow global heating: the seas have responded by absorbing more and more carbon dioxide from the atmosphere.

But should humans come to grips with the challenge of looming climate catastrophe and start to reduce emissions, the oceans could respond again – by absorbing less and slightly slowing the fall of the mercury in the global thermometer.

And there is even an immediate chance to test this proposal: if so, then oceans that have been each year absorbing more and more carbon from the atmosphere as greenhouse gas ratios rise will go into brief reverse, because of the global economic shutdown and fall in emissions triggered by the global pandemic of Covid-19.

For the first time in decades, the oceans could take up less carbon dioxide in 2020, according to a new study by US scientists in the American Geophysical Union journal AGU Advances.

“We didn’t realise until we did this work that these external forcings, like changes in the growth of atmospheric carbon dioxide, dominate the variability in the global ocean on year-to-year timescales. That’s a real surprise,” said Galen McKinley, of Columbia University’s Lamont-Doherty Earth Observatory.

Feedback in action

“As we reduce our emissions and the growth rate of atmospheric carbon dioxide slows down, it’s important to realise that the ocean carbon sink will respond by slowing down.”

The research should not be interpreted as an invitation to go on burning fossil fuels. It is another lesson in the intricacy of the traffic between atmosphere, rocks, oceans, and living things in an evolving world. And it is more immediately an exquisite example of what engineers call feedback.

In cases of negative feedback, the agency of change also triggers a way of slowing that change. Since 1750 – the birth of the Industrial Revolution – human economies have added 440 billion tonnes of carbon to the planetary atmosphere.

For most of human history carbon dioxide ratios in the atmosphere had hovered around 285 parts per million. They have now gone beyond 400 ppm, and global average temperatures have already risen by more than 1°C.

They’d be even higher but for the oceans, which have responded by absorbing around 39% of all that extra carbon from coal, oil and gas combustion. So the oceans are sensitive to atmospheric change, and respond.

“There will be a time when the ocean will limit the effectiveness of mitigation actions, and this should be accounted for in policymaking”

The latest study is a lesson in how sensitive: Professor McKinley and her colleagues used computer models to try to understand better why the ocean uptake of carbon varies.

In the early 1990s, the ocean absorption of carbon dioxide varied: dramatically at first, because a devastating volcanic eruption of Mt Pinatubo in the Philippines in 1991 that darkened the stratosphere also accelerated ocean uptake.

And then the ocean uptake started to slow, as the skies cleared but also as the collapse of the Soviet Union and its satellite nations changed the global pattern of fuel use. It went on declining until 2001, when fossil fuel use started to accelerate. And then the ocean sink started once again to become more absorbent.

Such research is a reminder of how much scientists still don’t know about the machinery of the planet. That greenhouse gas from fossil fuel combustion drives global heating is not now in doubt. But the precise speed, and the drivers and brakes of positive and negative feedback, remain less certain.

Many feedbacks are positive: as the Arctic warms, carbon plant remains frozen in the permafrost will start to decay, release more methane and carbon dioxide, and accelerate warming.

Forest concern

As the sea ice retreats, and the ice reflects less sunlight, the exposed blue seas will absorb ever more radiation, to turn up the planetary temperatures. A warner world will be a wetter one, which may also mean a rise in the rate of warming.

But the ocean is not the only example of negative feedback. More carbon dioxide seems to mean more vigorous plant growth, and there is clear evidence that the world’s great forests are an important carbon sink: an example of negative feedback. That is why almost all governments recognise the importance of forest conservation.

Action however is uneven, forests are still being degraded, and there is alarming evidence that at some point, as temperatures get too high, the tropical forests could start surrendering the carbon they have for millennia absorbed, and become agents of positive feedback.

Professor McKinley warns that – as global emissions are cut – there will be a phase during which ocean uptake slows. If so, then planetary temperature rise will not slow as fast as hoped: extra carbon dioxide will linger, to contribute to warming.

“We need to discuss this coming feedback. We want people to understand that there will be a time when the ocean will limit the effectiveness of mitigation actions, and this should also be accounted for in policymaking.” – Climate News Network

Forest trees are growing shorter and dying younger

Temperatures could get too high for tropical forests, and forest trees everywhere are changing in response to human action.

LONDON, 9 June, 2020 – There are limits to what forest trees will tolerate; many tropical forests, for instance, can cope with climate change – but only up to a point. Again, they will go on storing carbon from human greenhouse gas emissions – but only to a degree.

But at around the 32°C threshold, tree growth halts and trees start to die more frequently, putting carbon back into the atmosphere, to accelerate more global heating, according to a detailed study of trees in more than 800 tropical forests.

And a second, unrelated study of forests worldwide finds separate evidence of the impact of climate change. Thanks to human action, forest trees are now younger – and shorter.

The point of the first study is that, in their natural and undisturbed state, the world’s tropical forests can take the heat, but there may be a limit to their capacity for change, and that limit is a daytime maximum of 32.2°C.

A collective of 225 researchers in South America, Africa and Asia report in the journal Science that they made 2 million measurements of 10,000 tropical tree species in sample plots in 24 countries to examine the capacity of forests to absorb atmospheric carbon in a rapidly heating world.

Safety zone

“Our analysis reveals that up to a certain point of heating, tropical forests are surprisingly resistant to small temperature differences. If we limit climate change they can continue to store a large amount of carbon in a warmer world,” said Martin Sullivan, a geographer at the University of Leeds, and at Manchester Metropolitan University, who led the study.

“The 32-degree threshold highlights the critical importance of cutting our emissions to avoid pushing too many forests beyond the safety zone.

“For example, if we limit global average temperatures to a 2°C increase above pre-industrial levels, this pushes nearly three-quarters of tropical forests above the heat threshold we identified. Any further increases in temperature will lead to rapid losses of forest carbon.”

The finding suggests that overall, and independently of species of tree, tropical forest carbon declines with higher temperatures. In all forests, trees flourish and absorb carbon, die back and release it again. But at their best, forests on balance absorb and store away for centuries more carbon than they release – until the thermometer starts to rise and goes on rising.

“Reductions in forest age and height are already happening, and they’re likely to continue to happen”

A co-author, Beatriz Marimon of the State University of Matto Grosso in Brazil, said: “Each degree increase above this 32-degree threshold releases four times as much carbon as would have been released below the threshold.”

The message is that tropical forests need to be protected from climate change, deforestation and wildlife exploitation: that way, they protect  biodiversity, protect themselves, and protect humankind, for future generations. They can adapt to warming temperatures, but this takes decades, perhaps centuries.

But according to another study, also in Science, forest trees the world over are now changing. They are responding to ever higher levels of atmospheric carbon – in effect, they are being fertilised – but also wildfire, drought, windstorm damage, insect attack and disease have become more frequent and more severe with climate change.

And then there has been the direct impact of human economic demand: clearance, disturbance and economic exploitation.

In consequence, US and European scientists conclude, from detailed satellite data and from reviews of more than 160 previous studies, that there has been a “pervasive shift” in forest dynamics, and a dramatic decrease in the age and stature of the forests. The world’s trees on average are younger, and shorter.

Drastic change

“This trend is likely to continue with global warming,” said Nate McDowell,  of the Pacific Northwest National Laboratory, who led the research.

“A future planet with fewer large, old forests will be very different than what we have grown accustomed to. Older forests often host much higher biodiversity than young forests, and they store more carbon than young forests.”

So direct and indirect human action have – in the big picture – affected the way forests shelter new seedlings, the growth of all trees, and the rate of death of those trees. Mortality is going up, while recruitment and growth are faltering.

“Unfortunately, mortality drivers like rising temperature and disturbances are on the rise and are expected to continue increasing in frequency over the next century,” Dr McDowell said.

“So reductions in forest age and height are already happening, and they’re likely to continue to happen.” – Climate News Network

Temperatures could get too high for tropical forests, and forest trees everywhere are changing in response to human action.

LONDON, 9 June, 2020 – There are limits to what forest trees will tolerate; many tropical forests, for instance, can cope with climate change – but only up to a point. Again, they will go on storing carbon from human greenhouse gas emissions – but only to a degree.

But at around the 32°C threshold, tree growth halts and trees start to die more frequently, putting carbon back into the atmosphere, to accelerate more global heating, according to a detailed study of trees in more than 800 tropical forests.

And a second, unrelated study of forests worldwide finds separate evidence of the impact of climate change. Thanks to human action, forest trees are now younger – and shorter.

The point of the first study is that, in their natural and undisturbed state, the world’s tropical forests can take the heat, but there may be a limit to their capacity for change, and that limit is a daytime maximum of 32.2°C.

A collective of 225 researchers in South America, Africa and Asia report in the journal Science that they made 2 million measurements of 10,000 tropical tree species in sample plots in 24 countries to examine the capacity of forests to absorb atmospheric carbon in a rapidly heating world.

Safety zone

“Our analysis reveals that up to a certain point of heating, tropical forests are surprisingly resistant to small temperature differences. If we limit climate change they can continue to store a large amount of carbon in a warmer world,” said Martin Sullivan, a geographer at the University of Leeds, and at Manchester Metropolitan University, who led the study.

“The 32-degree threshold highlights the critical importance of cutting our emissions to avoid pushing too many forests beyond the safety zone.

“For example, if we limit global average temperatures to a 2°C increase above pre-industrial levels, this pushes nearly three-quarters of tropical forests above the heat threshold we identified. Any further increases in temperature will lead to rapid losses of forest carbon.”

The finding suggests that overall, and independently of species of tree, tropical forest carbon declines with higher temperatures. In all forests, trees flourish and absorb carbon, die back and release it again. But at their best, forests on balance absorb and store away for centuries more carbon than they release – until the thermometer starts to rise and goes on rising.

“Reductions in forest age and height are already happening, and they’re likely to continue to happen”

A co-author, Beatriz Marimon of the State University of Matto Grosso in Brazil, said: “Each degree increase above this 32-degree threshold releases four times as much carbon as would have been released below the threshold.”

The message is that tropical forests need to be protected from climate change, deforestation and wildlife exploitation: that way, they protect  biodiversity, protect themselves, and protect humankind, for future generations. They can adapt to warming temperatures, but this takes decades, perhaps centuries.

But according to another study, also in Science, forest trees the world over are now changing. They are responding to ever higher levels of atmospheric carbon – in effect, they are being fertilised – but also wildfire, drought, windstorm damage, insect attack and disease have become more frequent and more severe with climate change.

And then there has been the direct impact of human economic demand: clearance, disturbance and economic exploitation.

In consequence, US and European scientists conclude, from detailed satellite data and from reviews of more than 160 previous studies, that there has been a “pervasive shift” in forest dynamics, and a dramatic decrease in the age and stature of the forests. The world’s trees on average are younger, and shorter.

Drastic change

“This trend is likely to continue with global warming,” said Nate McDowell,  of the Pacific Northwest National Laboratory, who led the research.

“A future planet with fewer large, old forests will be very different than what we have grown accustomed to. Older forests often host much higher biodiversity than young forests, and they store more carbon than young forests.”

So direct and indirect human action have – in the big picture – affected the way forests shelter new seedlings, the growth of all trees, and the rate of death of those trees. Mortality is going up, while recruitment and growth are faltering.

“Unfortunately, mortality drivers like rising temperature and disturbances are on the rise and are expected to continue increasing in frequency over the next century,” Dr McDowell said.

“So reductions in forest age and height are already happening, and they’re likely to continue to happen.” – Climate News Network

Pandemic and climate extremes hit India together

A fearsome cyclone, other climate extremes, Covid-19 and now locust swarms – Indians may think life could hardly get worse.

DELHI, 2 June, 2020 – India is no stranger to coping with climate extremes and natural emergencies, but this year is likely to lodge in the national memory as one of the most challenging in recent history.

The Covid-19 pandemic is a global scourge, but India also has many regional and national afflictions to make 2020 a year to forget – a massive heatwave, its strongest recorded cyclone, thunderstorms bringing huge hailstones, and floods. Now it is being assailed by all-devouring locust swarms, the worst in 25 years, leaving the land scarred.

Government figures showed more than 5,000 Covid-19 deaths by the end of May. The pandemic is causing a humanitarian crisis as well, with a huge reverse migration of penniless unskilled labourers who have lost their jobs in the cities and are now returning to their rural homes.

Five states – Rajasthan, Gujarat, Punjab, Madhya Pradesh and parts of Maharashtra – have been invaded by the locusts. The swarms normally arrive to breed in June or July but this year the first flew in in mid-April, helped to spread by a strong west wind. Climate scientists say warmer waters in the western Indian Ocean also worsened the problem.

The only saving grace is that there are not many standing crops in many of the affected districts, as the monsoon sowing is yet to begin. “It is only the vegetables, orchards and trees that are the victims of this attack,” an official said.

“This is an emergency situation. These desert locusts will not only leave a severe impact on India’s food production but also deal a double whammy to the farmers, who are already reeling from the economic lockdown”

As the locust threat developed, a range of devastating climate events hit the country in May, starting with heavy rain and hail which killed 29 people in Uttar Pradesh, India’s most populous state. Next came Cyclone Amphan, bringing sustained windspeeds of 270 kms per hour.

It was the strongest storm ever recorded in the Bay of Bengal. When it hit the coast on 20 May more than 80 people died. West Bengal, on the eastern coast bordering Bangladesh, suffered a trail of destruction. The winds even damaged the tiger stronghold of the Sundarbans, the islands  whose mangrove forests in the delta of three major rivers normally give Bengal some protection from the storms.

Amphan’s rampage caused the evacuation of 300,000 people to shelter. Many acres of agricultural land near the coast were flooded by salty water and are now unusable. The government estimated the initial losses caused by the cyclone at one trillion rupees (US$13.2 billion).

Amphan’s storm surge was among its most dangerous threats. Global sea levels have already increased by about 23 cm as a result of human carbon emissions – dramatically increasing the distance that the surges can reach. Sea levels in the North Indian Ocean have risen more quickly than in many oceans elsewhere in recent years.

Assam struck

Amphan’s tail also left its mark on the northeastern state of Assam, which experienced heavy rainfall and flooding in low-lying areas, and then several days later a massive thunderstorm. On 27 May, as the Brahmaputra and its tributaries rose above danger point at several places, over 300 villages experienced heavy flooding.

Nor was that all. The same week maximum temperatures reached 40-45C° in much of northern and central India. While Delhi sizzled at 45-46°, Churu in Rajasthan touched 50°C. Fortunately, there have been no deaths reported this year of farm workers and street vendors, as many people remain locked in their homes because of the virus.

As India braces for the annual monsoon, the government is claiming that it has contained much of the locust threat. But Devinder Sharma, an agriculture and trade policy expert, said: “The government’s preparedness has been too slow to keep pace with this rapid increase in locust swarms.

“This is an emergency situation and requires emergency measures. These desert locusts will not only leave a severe impact on India’s food production but also deal a double whammy to the farmers, who are already reeling from the economic lockdown caused by Covid-19.” – Climate News Network

* * * * * * *

Nivedita Khandekar is an independent journalist based in Delhi. She writes on environmental and developmental issues. She can be reached at nivedita_him@rediffmail.com or @nivedita_Him

A fearsome cyclone, other climate extremes, Covid-19 and now locust swarms – Indians may think life could hardly get worse.

DELHI, 2 June, 2020 – India is no stranger to coping with climate extremes and natural emergencies, but this year is likely to lodge in the national memory as one of the most challenging in recent history.

The Covid-19 pandemic is a global scourge, but India also has many regional and national afflictions to make 2020 a year to forget – a massive heatwave, its strongest recorded cyclone, thunderstorms bringing huge hailstones, and floods. Now it is being assailed by all-devouring locust swarms, the worst in 25 years, leaving the land scarred.

Government figures showed more than 5,000 Covid-19 deaths by the end of May. The pandemic is causing a humanitarian crisis as well, with a huge reverse migration of penniless unskilled labourers who have lost their jobs in the cities and are now returning to their rural homes.

Five states – Rajasthan, Gujarat, Punjab, Madhya Pradesh and parts of Maharashtra – have been invaded by the locusts. The swarms normally arrive to breed in June or July but this year the first flew in in mid-April, helped to spread by a strong west wind. Climate scientists say warmer waters in the western Indian Ocean also worsened the problem.

The only saving grace is that there are not many standing crops in many of the affected districts, as the monsoon sowing is yet to begin. “It is only the vegetables, orchards and trees that are the victims of this attack,” an official said.

“This is an emergency situation. These desert locusts will not only leave a severe impact on India’s food production but also deal a double whammy to the farmers, who are already reeling from the economic lockdown”

As the locust threat developed, a range of devastating climate events hit the country in May, starting with heavy rain and hail which killed 29 people in Uttar Pradesh, India’s most populous state. Next came Cyclone Amphan, bringing sustained windspeeds of 270 kms per hour.

It was the strongest storm ever recorded in the Bay of Bengal. When it hit the coast on 20 May more than 80 people died. West Bengal, on the eastern coast bordering Bangladesh, suffered a trail of destruction. The winds even damaged the tiger stronghold of the Sundarbans, the islands  whose mangrove forests in the delta of three major rivers normally give Bengal some protection from the storms.

Amphan’s rampage caused the evacuation of 300,000 people to shelter. Many acres of agricultural land near the coast were flooded by salty water and are now unusable. The government estimated the initial losses caused by the cyclone at one trillion rupees (US$13.2 billion).

Amphan’s storm surge was among its most dangerous threats. Global sea levels have already increased by about 23 cm as a result of human carbon emissions – dramatically increasing the distance that the surges can reach. Sea levels in the North Indian Ocean have risen more quickly than in many oceans elsewhere in recent years.

Assam struck

Amphan’s tail also left its mark on the northeastern state of Assam, which experienced heavy rainfall and flooding in low-lying areas, and then several days later a massive thunderstorm. On 27 May, as the Brahmaputra and its tributaries rose above danger point at several places, over 300 villages experienced heavy flooding.

Nor was that all. The same week maximum temperatures reached 40-45C° in much of northern and central India. While Delhi sizzled at 45-46°, Churu in Rajasthan touched 50°C. Fortunately, there have been no deaths reported this year of farm workers and street vendors, as many people remain locked in their homes because of the virus.

As India braces for the annual monsoon, the government is claiming that it has contained much of the locust threat. But Devinder Sharma, an agriculture and trade policy expert, said: “The government’s preparedness has been too slow to keep pace with this rapid increase in locust swarms.

“This is an emergency situation and requires emergency measures. These desert locusts will not only leave a severe impact on India’s food production but also deal a double whammy to the farmers, who are already reeling from the economic lockdown caused by Covid-19.” – Climate News Network

* * * * * * *

Nivedita Khandekar is an independent journalist based in Delhi. She writes on environmental and developmental issues. She can be reached at nivedita_him@rediffmail.com or @nivedita_Him

South Asia’s twin threat: extreme heat and foul air

Climate change means many health risks. Any one of them raises the danger. What happens when extreme heat meets bad air?

LONDON, 29 May, 2020 – Extreme heat can kill. Air pollution can seriously shorten human lives. By 2050, extreme summer heat will threaten about 2 billion people on and around the Indian sub-continent for around 78 days every year. And the chances of unbearable heat waves and choking atmospheric chemistry at the same time will rise by 175%.

Climate scientists have been warning for decades that what were once rare events – for instance the 2003 heat wave that claimed tens of thousands of lives in Europe – will, as global average temperatures rise, become the new normal.

And they have repeatedly warned that in step with extreme summer temperatures, extreme humidity is also likely to increase in some regions, and to levels that could prove potentially fatal for outdoor workers and people in crowded cities.

The link between air pollution and ill health was established 60 or more years ago and has been confirmed again and again with mortality statistics.

Risk to megacities

Now a team from China and the US confirms once more in the journal  AGU Advances, published by the American Geophysical Union, that the danger is real, and that they can tell where it is becoming immediate: in seven nations that stretch from Afghanistan to Myanmar, and from Nepal to the tip of southern India.

Around 1.5bn people live there now, and they are already learning to live with around 45 days of extreme heat every year. By 2050, there will be 2bn people, most of them crammed into megacities in Afghanistan, Bangladesh, Bhutan, India, Myanmar, Nepal and Pakistan, and climate models confirm that the number of days of extreme heat could rise to 78 a year.

The number of days on which cities – already blighted by air pollution – reach health-threatening levels of high particulate matter will also rise. When heat and choking air chemistry become too much, lives will be at risk.

That extremes of summer heat are on the increase is now a given. That the intensity, duration and frequency of heat waves will go on rising has also been established. Extremes of heat are a threat to crops and a particular hazard in cities already much hotter than their surrounding landscapes.

“South Asia is a hotspot for future climate change impacts. Much research is needed over other parts of the world on  the risks they pose, and their potential human health effects”

One research group has identified 27 ways in which high temperatures can kill. Others have repeatedly warned of the dangerous mix of high temperatures and high humidity (climate scientists call it the “wet bulb” temperature), and one team of scientists has already argued that such conditions have already arrived, albeit so far for short periods and in limited locations.

The researchers chose the so-called wet-bulb temperature of 25°C as their threshold for an unhealthy extreme, and then worked out the number of days a year that such conditions happened in South Asia: between 1994 and 2006, these arrived at an average of between 40 and 50 days a year.

They then looked at the likely rise with forecast increases in average planetary temperature, depending on how vigorously or feebly the world’s nations tried to switch from fossil fuels to renewable energy sources. The probability increased by 75%.

They then chose widely-agreed dangerous thresholds for air pollution with soot, and sulphate aerosols, usually from fossil fuel combustion, to find that extremes of pollution would happen by 2050 on around 132 days a year.

Tenfold risk increase

Then they tried to estimate the probabilities that extreme pollution and extreme heat would coincide. They judged that the frequency of these more than usually hazardous days would rise by 175%, and they would last an estimated 79% longer. The area of land exposed to this double assault on human health would by then have increased tenfold.

Scientific publications usually avoid emotional language, but the researchers call their own finding “alarming.”

“South Asia is a hotspot for future climate change impacts,” said Yangyang Xu, of Texas A&M University, the first author.

“I think this study raises a lot of important concerns, and much research is needed over other parts of the world on these compounded extremes, the risks they pose, and their potential human health effects.” – Climate News Network

Climate change means many health risks. Any one of them raises the danger. What happens when extreme heat meets bad air?

LONDON, 29 May, 2020 – Extreme heat can kill. Air pollution can seriously shorten human lives. By 2050, extreme summer heat will threaten about 2 billion people on and around the Indian sub-continent for around 78 days every year. And the chances of unbearable heat waves and choking atmospheric chemistry at the same time will rise by 175%.

Climate scientists have been warning for decades that what were once rare events – for instance the 2003 heat wave that claimed tens of thousands of lives in Europe – will, as global average temperatures rise, become the new normal.

And they have repeatedly warned that in step with extreme summer temperatures, extreme humidity is also likely to increase in some regions, and to levels that could prove potentially fatal for outdoor workers and people in crowded cities.

The link between air pollution and ill health was established 60 or more years ago and has been confirmed again and again with mortality statistics.

Risk to megacities

Now a team from China and the US confirms once more in the journal  AGU Advances, published by the American Geophysical Union, that the danger is real, and that they can tell where it is becoming immediate: in seven nations that stretch from Afghanistan to Myanmar, and from Nepal to the tip of southern India.

Around 1.5bn people live there now, and they are already learning to live with around 45 days of extreme heat every year. By 2050, there will be 2bn people, most of them crammed into megacities in Afghanistan, Bangladesh, Bhutan, India, Myanmar, Nepal and Pakistan, and climate models confirm that the number of days of extreme heat could rise to 78 a year.

The number of days on which cities – already blighted by air pollution – reach health-threatening levels of high particulate matter will also rise. When heat and choking air chemistry become too much, lives will be at risk.

That extremes of summer heat are on the increase is now a given. That the intensity, duration and frequency of heat waves will go on rising has also been established. Extremes of heat are a threat to crops and a particular hazard in cities already much hotter than their surrounding landscapes.

“South Asia is a hotspot for future climate change impacts. Much research is needed over other parts of the world on  the risks they pose, and their potential human health effects”

One research group has identified 27 ways in which high temperatures can kill. Others have repeatedly warned of the dangerous mix of high temperatures and high humidity (climate scientists call it the “wet bulb” temperature), and one team of scientists has already argued that such conditions have already arrived, albeit so far for short periods and in limited locations.

The researchers chose the so-called wet-bulb temperature of 25°C as their threshold for an unhealthy extreme, and then worked out the number of days a year that such conditions happened in South Asia: between 1994 and 2006, these arrived at an average of between 40 and 50 days a year.

They then looked at the likely rise with forecast increases in average planetary temperature, depending on how vigorously or feebly the world’s nations tried to switch from fossil fuels to renewable energy sources. The probability increased by 75%.

They then chose widely-agreed dangerous thresholds for air pollution with soot, and sulphate aerosols, usually from fossil fuel combustion, to find that extremes of pollution would happen by 2050 on around 132 days a year.

Tenfold risk increase

Then they tried to estimate the probabilities that extreme pollution and extreme heat would coincide. They judged that the frequency of these more than usually hazardous days would rise by 175%, and they would last an estimated 79% longer. The area of land exposed to this double assault on human health would by then have increased tenfold.

Scientific publications usually avoid emotional language, but the researchers call their own finding “alarming.”

“South Asia is a hotspot for future climate change impacts,” said Yangyang Xu, of Texas A&M University, the first author.

“I think this study raises a lot of important concerns, and much research is needed over other parts of the world on these compounded extremes, the risks they pose, and their potential human health effects.” – Climate News Network

US farm workers face worsening lethal heat

By 2100, US farmers can expect more lethal heat, the equivalent of two months when it’s unsafe to pick crops.

LONDON, 6 May, 2020 – Life is already bad enough for underpaid and overworked crop pickers in the US, but as lethal heat levels rise they will render outdoor labour in the harvest season increasingly impossible.

The men and women who gather melons and strawberries, nuts and grapes, onions and lettuce already find conditions too hot to handle on at least 21 days a year.

By 2050, US agricultural workers will meet unsafe daytime summer temperatures on 39 days each harvest season. And by 2100, this number could triple to 62 unsafe days, according to new research.

Unsafe means that the levels of high thermometer readings and high humidity outdoors could put field workers at risk of heat exhaustion, heat stroke, heat cramps, dehydration, potential kidney injury and even death.

There are roughly one million people in the US officially employed picking crops in states such as Oregon, California, Washington and Florida. The actual number however is estimated to be two million.

“You don’t have to go to the global south to find people who will get hurt with even modest amounts of global warming – you just have to look in your own backyard”

More than three-quarters of them are foreign-born, many from Mexico. Only about half of these have lawful authority to work in the US. Of these, 71% do not speak English well, and on average educational levels are low. Fewer than half have medical insurance, and one third of the families of agricultural workers live below the poverty line.

Their housing and sanitary conditions are often not good, they are often paid on the basis of crops picked, so that to survive they must neglect breaks and work for longer, and they are often deprived of shade, according to data compiled in the journal Environmental Research Letters.

High summer extremes are a hazard, and can cause death on a significant scale. Climate scientists have established that by the century’s end, more than a billion people worldwide will be placed in danger of summer extremes, and the risks are growing.

One enterprising group has even numbered 27 ways in which high temperatures and high humidity can kill. Economists have already counted the price paid in falling productivity in severe conditions in Australia, and – since fruit tends to ripen as the thermometer rises and must be picked at the right moment – the hazards faced by grape-pickers in the world’s vineyards.

When Michelle Tigchelaar began her study of the climate impacts, she was at the University of Washington. She is now at Stanford University in California.

Low estimate

She and colleagues simply followed the climate projections and the impact rising global average temperatures will have on the intensity, frequency and duration of heat waves, and found that with a 2°C rise, expected by 2050, the level of unsafe days leapt from 21 to 39. At 4°C – and there is a high risk on present trends – then unsafe conditions could by 2100 reach 62 days.

“I was surprised by the scale of the change – seeing a doubling of unsafe days by mid-century, then a tripling by 2100. And we think that’s a low estimate,” Dr Tigchelaar said.

“The people who are the most vulnerable are asked to take the highest risk so that we, as consumers, can eat a healthy nutritious diet.”

And her co-author David Battisti of the University of Washington said: “The climate science community has long been pointing to the global south, the developing countries, as places that will be disproportionately affected by climate change.

“This shows that you don’t have to go to the global south to find people who will get hurt with even modest amounts of global warming – you just have to look in your own backyard.” – Climate News Network

By 2100, US farmers can expect more lethal heat, the equivalent of two months when it’s unsafe to pick crops.

LONDON, 6 May, 2020 – Life is already bad enough for underpaid and overworked crop pickers in the US, but as lethal heat levels rise they will render outdoor labour in the harvest season increasingly impossible.

The men and women who gather melons and strawberries, nuts and grapes, onions and lettuce already find conditions too hot to handle on at least 21 days a year.

By 2050, US agricultural workers will meet unsafe daytime summer temperatures on 39 days each harvest season. And by 2100, this number could triple to 62 unsafe days, according to new research.

Unsafe means that the levels of high thermometer readings and high humidity outdoors could put field workers at risk of heat exhaustion, heat stroke, heat cramps, dehydration, potential kidney injury and even death.

There are roughly one million people in the US officially employed picking crops in states such as Oregon, California, Washington and Florida. The actual number however is estimated to be two million.

“You don’t have to go to the global south to find people who will get hurt with even modest amounts of global warming – you just have to look in your own backyard”

More than three-quarters of them are foreign-born, many from Mexico. Only about half of these have lawful authority to work in the US. Of these, 71% do not speak English well, and on average educational levels are low. Fewer than half have medical insurance, and one third of the families of agricultural workers live below the poverty line.

Their housing and sanitary conditions are often not good, they are often paid on the basis of crops picked, so that to survive they must neglect breaks and work for longer, and they are often deprived of shade, according to data compiled in the journal Environmental Research Letters.

High summer extremes are a hazard, and can cause death on a significant scale. Climate scientists have established that by the century’s end, more than a billion people worldwide will be placed in danger of summer extremes, and the risks are growing.

One enterprising group has even numbered 27 ways in which high temperatures and high humidity can kill. Economists have already counted the price paid in falling productivity in severe conditions in Australia, and – since fruit tends to ripen as the thermometer rises and must be picked at the right moment – the hazards faced by grape-pickers in the world’s vineyards.

When Michelle Tigchelaar began her study of the climate impacts, she was at the University of Washington. She is now at Stanford University in California.

Low estimate

She and colleagues simply followed the climate projections and the impact rising global average temperatures will have on the intensity, frequency and duration of heat waves, and found that with a 2°C rise, expected by 2050, the level of unsafe days leapt from 21 to 39. At 4°C – and there is a high risk on present trends – then unsafe conditions could by 2100 reach 62 days.

“I was surprised by the scale of the change – seeing a doubling of unsafe days by mid-century, then a tripling by 2100. And we think that’s a low estimate,” Dr Tigchelaar said.

“The people who are the most vulnerable are asked to take the highest risk so that we, as consumers, can eat a healthy nutritious diet.”

And her co-author David Battisti of the University of Washington said: “The climate science community has long been pointing to the global south, the developing countries, as places that will be disproportionately affected by climate change.

“This shows that you don’t have to go to the global south to find people who will get hurt with even modest amounts of global warming – you just have to look in your own backyard.” – Climate News Network

Extreme summer heat puts millions at risk

heat

Summer on much of the planet could get too hot for comfort by the end of the century, with more than a billion people seriously affected by extreme heat.

LONDON, 20 March, 2020 – As many as 1.2 billion people could be at risk of serious medical stress by the year 2100 simply on the basis of the extreme summer temperatures forecast if greenhouse gas emissions continue to rise, according to new research.

The finding is, in essence, a confirmation of earlier studies: researchers looked closely at the threat to health and, indeed, to life in a globally-heating world have already made a calculation that “more than a billion” could be at risk not just from soaring summer temperatures over longer periods, but also from heightened humidity.

Urgent question

One study found that heat extremes can kill in up to 27 different ways. And lethal heat waves in Europe in 2003, Russia in 2010 and Australia in 2012/2013 have confirmed this in the most unwelcome way possible.

But a study published in Environmental Research Letters journal takes a simple statistical approach to this increasingly urgent question and settles on a notional temperature that factors in not just how high the mercury rises but also how much water vapour might be in the air.

This is known to meteorologists as a “wet bulb” temperature. And the consensus is that, for fit, healthy, acclimatised people, a wet bulb temperature of 33°C is about the limit of tolerance – putting the very young, the very old, and the already ill at risk.

“Every bit of global warming makes hot, humid days more frequent and intense”

Humans can survive much higher thermometer readings in dry climates, but are designed to shed surplus body heat through perspiration – something that becomes increasingly difficult as atmospheric humidity begins to rise. Then the risks of heat rash, heat cramps, heat exhaustion and heat stroke begin to multiply.

So researchers in the US looked at how heat and humidity will increase in a warming planet, for the existing population, and played with 40 climate simulations to build up a picture of probabilities as humans burned more fossil fuels, stoked levels of greenhouse gases in the atmosphere, and turned up the planetary thermostat.

They calculated that, by 2100, the numbers at risk of sweltering, gasping and sickening heat extremes will have multiplied.

The planet is already around 1.2°C warmer than it was at the start of the Industrial Revolution. If the temperature notches up to 1.5°C above the long-term average for most of human history, then every year an estimated 500 million could be exposed to unsafe extremes.

If the temperature rises by 2°C – the upper limit the world set itself in an historic Paris climate meeting in 2015 – the numbers at risk would reach 800 million.

And if the planetary average annual temperature rise was by 3°C – and right now the planet is on course to exceed even that figure – then an estimated 1.2 billion would at least once a year be at risk of extended spells of dangerous heat and humidity.

Research leader Dawei Li, once of Rutgers University and now postdoctoral associate in the Department of Geosciences at the University of Massachusetts, says: “Every bit of global warming makes hot, humid days more frequent and intense.

“In New York City, for example, the hottest, most humid day in a typical year already occurs about 11 times more frequently than it would have done in the 19th century.” Climate News Network

Summer on much of the planet could get too hot for comfort by the end of the century, with more than a billion people seriously affected by extreme heat.

LONDON, 20 March, 2020 – As many as 1.2 billion people could be at risk of serious medical stress by the year 2100 simply on the basis of the extreme summer temperatures forecast if greenhouse gas emissions continue to rise, according to new research.

The finding is, in essence, a confirmation of earlier studies: researchers looked closely at the threat to health and, indeed, to life in a globally-heating world have already made a calculation that “more than a billion” could be at risk not just from soaring summer temperatures over longer periods, but also from heightened humidity.

Urgent question

One study found that heat extremes can kill in up to 27 different ways. And lethal heat waves in Europe in 2003, Russia in 2010 and Australia in 2012/2013 have confirmed this in the most unwelcome way possible.

But a study published in Environmental Research Letters journal takes a simple statistical approach to this increasingly urgent question and settles on a notional temperature that factors in not just how high the mercury rises but also how much water vapour might be in the air.

This is known to meteorologists as a “wet bulb” temperature. And the consensus is that, for fit, healthy, acclimatised people, a wet bulb temperature of 33°C is about the limit of tolerance – putting the very young, the very old, and the already ill at risk.

“Every bit of global warming makes hot, humid days more frequent and intense”

Humans can survive much higher thermometer readings in dry climates, but are designed to shed surplus body heat through perspiration – something that becomes increasingly difficult as atmospheric humidity begins to rise. Then the risks of heat rash, heat cramps, heat exhaustion and heat stroke begin to multiply.

So researchers in the US looked at how heat and humidity will increase in a warming planet, for the existing population, and played with 40 climate simulations to build up a picture of probabilities as humans burned more fossil fuels, stoked levels of greenhouse gases in the atmosphere, and turned up the planetary thermostat.

They calculated that, by 2100, the numbers at risk of sweltering, gasping and sickening heat extremes will have multiplied.

The planet is already around 1.2°C warmer than it was at the start of the Industrial Revolution. If the temperature notches up to 1.5°C above the long-term average for most of human history, then every year an estimated 500 million could be exposed to unsafe extremes.

If the temperature rises by 2°C – the upper limit the world set itself in an historic Paris climate meeting in 2015 – the numbers at risk would reach 800 million.

And if the planetary average annual temperature rise was by 3°C – and right now the planet is on course to exceed even that figure – then an estimated 1.2 billion would at least once a year be at risk of extended spells of dangerous heat and humidity.

Research leader Dawei Li, once of Rutgers University and now postdoctoral associate in the Department of Geosciences at the University of Massachusetts, says: “Every bit of global warming makes hot, humid days more frequent and intense.

“In New York City, for example, the hottest, most humid day in a typical year already occurs about 11 times more frequently than it would have done in the 19th century.” Climate News Network

Shrinking Arctic ice slows fish breeding rates

A food source for many species spawns under the Arctic ice. Now fish breeding problems, caused by ice melt, threaten its future.

LONDON, 3 March, 2020 − It’s relatively small, not particularly well-known, but it’s a key indicator of global warming, which is putting some fish breeding rates at risk: enter the polar cod (Boreogadus saida), the smaller cousin of the more familiar north-east Arctic cod.

A recent study by researchers at the Institute of Marine Research (IMR) in Norway has found that declines in winter sea ice cover in the Barents Sea region of the Arctic, plus warmer sea temperatures, are causing declines in polar cod reproduction rates.

This has grave implications − not just for future stocks of polar cod, but for the survival of many other Arctic species as well. The polar cod is a vital part of the Arctic food chain. After spawning under the ice in the early months of the year, the fish – feeding on a diet of zooplankton − grows quickly. It then becomes a food for other larger fish and for sea birds, seals and whales.

“Unfortunately, climate projections suggest that the Barents Sea will become warmer and virtually ice-free as early as in 2030”, says Mats Huserbråten, one of the study’s authors. “The outlook for this cornerstone of the Arctic food chain is therefore bad.”

End of breeding

If trends in ice reduction and the heating of Arctic waters continue, the reproductive cycle of the polar cod could collapse, say the researchers.

The fish is endemic to the polar regions (found nowhere else) and has developed in ways which make it dependent on the presence of ice. Its eggs are spawned under the ice, where they grow, even in sub-freezing temperatures. The larvae then feed on the zooplankton − plentiful in mid-year, when the annual ice melt occurs.

Winter ice cover in the Arctic has been in decline since the 1970s, with a sizeable part of the reduction happening in the Barents Sea.

The polar cod stock there has been monitored annually by a joint Norwegian-Russian survey since 1986. In the IMR study, researchers found that not only were stocks diminishing, but that what are described as spawning assemblages of the polar cod were moving further north.

“Climate projections suggest that the Barents Sea will become warmer and virtually ice-free as early as in 2030. The outlook for this cornerstone of the Arctic food chain is therefore bad”

As climate change warms the planet’s oceans, many fish species have been observed moving away from the equator in search of cooler waters. While such fish movements have resulted in bigger catches in some areas, fish stocks in many more southern regions are in sharp decline.

The reduction in winter ice cover in the Arctic caused by climate change is affecting a wide variety of species – from polar bears to the smallest marine life. It has also made the polar region more accessible – to cruise operators, shipping companies and to the fossil fuel industry.

The Norwegian study says growing human activity in the Arctic is putting further pressure on the polar cod and other vulnerable species.

“Together, these factors mean we need a better understanding of the possible impacts on Arctic ecosystems, to provide a basis for sustainable management of the high north”, say the researchers. “We have excellent tools at our disposal in the shape of models that can help us to understand trends and long-time series of survey data.” − Climate News Network

A food source for many species spawns under the Arctic ice. Now fish breeding problems, caused by ice melt, threaten its future.

LONDON, 3 March, 2020 − It’s relatively small, not particularly well-known, but it’s a key indicator of global warming, which is putting some fish breeding rates at risk: enter the polar cod (Boreogadus saida), the smaller cousin of the more familiar north-east Arctic cod.

A recent study by researchers at the Institute of Marine Research (IMR) in Norway has found that declines in winter sea ice cover in the Barents Sea region of the Arctic, plus warmer sea temperatures, are causing declines in polar cod reproduction rates.

This has grave implications − not just for future stocks of polar cod, but for the survival of many other Arctic species as well. The polar cod is a vital part of the Arctic food chain. After spawning under the ice in the early months of the year, the fish – feeding on a diet of zooplankton − grows quickly. It then becomes a food for other larger fish and for sea birds, seals and whales.

“Unfortunately, climate projections suggest that the Barents Sea will become warmer and virtually ice-free as early as in 2030”, says Mats Huserbråten, one of the study’s authors. “The outlook for this cornerstone of the Arctic food chain is therefore bad.”

End of breeding

If trends in ice reduction and the heating of Arctic waters continue, the reproductive cycle of the polar cod could collapse, say the researchers.

The fish is endemic to the polar regions (found nowhere else) and has developed in ways which make it dependent on the presence of ice. Its eggs are spawned under the ice, where they grow, even in sub-freezing temperatures. The larvae then feed on the zooplankton − plentiful in mid-year, when the annual ice melt occurs.

Winter ice cover in the Arctic has been in decline since the 1970s, with a sizeable part of the reduction happening in the Barents Sea.

The polar cod stock there has been monitored annually by a joint Norwegian-Russian survey since 1986. In the IMR study, researchers found that not only were stocks diminishing, but that what are described as spawning assemblages of the polar cod were moving further north.

“Climate projections suggest that the Barents Sea will become warmer and virtually ice-free as early as in 2030. The outlook for this cornerstone of the Arctic food chain is therefore bad”

As climate change warms the planet’s oceans, many fish species have been observed moving away from the equator in search of cooler waters. While such fish movements have resulted in bigger catches in some areas, fish stocks in many more southern regions are in sharp decline.

The reduction in winter ice cover in the Arctic caused by climate change is affecting a wide variety of species – from polar bears to the smallest marine life. It has also made the polar region more accessible – to cruise operators, shipping companies and to the fossil fuel industry.

The Norwegian study says growing human activity in the Arctic is putting further pressure on the polar cod and other vulnerable species.

“Together, these factors mean we need a better understanding of the possible impacts on Arctic ecosystems, to provide a basis for sustainable management of the high north”, say the researchers. “We have excellent tools at our disposal in the shape of models that can help us to understand trends and long-time series of survey data.” − Climate News Network

Timber buildings can help to slow global heating

Tomorrow’s town planners could take a leaf from nature’s book with timber buildings. More than a leaf: the whole tree and all the cuttings as well.

LONDON, 4 February, 2020 − European and US scientists have a root-and-branch answer to the challenge of tomorrow’s cities: switch to wood, construct timber buildings and reduce the risk of even more devastating global temperature rise.

Their reasoning is bold and simple: it takes energy to make steel and cement, which must be mined or quarried, a process that puts the remaining wilderness at risk.

Forests represent stored atmospheric carbon. If timber from the planet’s forests could be used to construct the houses and offices needed for the additional 2.3 billion urban dwellers expected by the year 2050, then that would mean that the great cities could become sinks or repositories of stored carbon.

And new trees could grow in the space left by the harvested timber to add to the world inventory of stored carbon. The new towns and cities could become a kind of bank vault in which to save up to 700 million tonnes of carbon a year that might otherwise have spilled into the atmosphere as the greenhouse gas carbon dioxide.

“Since the beginning of the industrial revolution we have been releasing into the atmosphere all of this carbon that had been stored in forests and in the ground,” said Galina Churkina, of the Potsdam Institute for Climate Impact Research, Germany.

“We wanted to show that there can be a vision for returning much of this carbon back into the land.”

Strong fire-resistance

Wood is a fuel. It burns well. Paradoxically tree trunks, and treated timber assembled from laminates, do not. Structural timbers may char in a fire, but this has been shown to make them more resistant to burning. Experiment and research has shown that buildings of engineered timber up to 18 stories in height can be resistant to fire.

In effect, atmospheric carbon, turned into high-strength wood fibre by photosynthesis, could be made as safe as reinforced concrete. But, according to a new study in the journal Nature Sustainability, in 2014 the making of cement spilled 1,320 million tonnes of carbon dioxide into the atmosphere and steel manufacture added another 1,740 million tonnes.

And between 2005 and 2015, mining in Brazil alone was responsible for 9% of the loss of all Amazon forest land during that decade: the act of prospecting for or extracting mineral commodities destroyed 12 times more than the areas stipulated in the mining leases.

The Potsdam scientists are not the first to suggest wood as an alternative to bricks and mortar, or bamboo as a replacement for cement, steel and glass. But their analysis may be the most detailed so far of a new way to confront the challenge of tomorrow’s climate-tested cities.

The researchers built a series of scenarios to test their hypothesis. New city structures must be built to accommodate an additional million or more humans every week for the next three decades. The proportion now expected to be fashioned from timber is half of 1%.

“Trees offer us a technology of unparalleled perfection. If we engineer the wood into modern building materials we humans can build ourselves a safe home on Earth”

A five-storey house made from laminated timber could store 180 kilos of carbon a square meter: that is three times the biomass above ground in natural forests. If construction from wood was stepped up to 10%, new construction could store 10 million tonnes of carbon a year; if the world switched to 90% this figure could rise to almost 700 million tonnes.

“Trees offer us a technology of unparalleled perfection,” said Hans Joachim Schellnhuber, a co-author of the study and a founder director of the Potsdam Institute.

“They take CO2 out of our atmosphere and smoothly transform it into oxygen for us to breathe and carbon in their trunks for us to use. There’s no safer way of storing carbon I can think of.

“Societies have made good use of wood for buildings for many centuries, yet now the challenge of climate stabilisation calls for a very serious upscaling. If we engineer the wood into modern building materials and smartly manage harvest and construction, we humans can build ourselves a safe home on Earth.” − Climate News Network

Tomorrow’s town planners could take a leaf from nature’s book with timber buildings. More than a leaf: the whole tree and all the cuttings as well.

LONDON, 4 February, 2020 − European and US scientists have a root-and-branch answer to the challenge of tomorrow’s cities: switch to wood, construct timber buildings and reduce the risk of even more devastating global temperature rise.

Their reasoning is bold and simple: it takes energy to make steel and cement, which must be mined or quarried, a process that puts the remaining wilderness at risk.

Forests represent stored atmospheric carbon. If timber from the planet’s forests could be used to construct the houses and offices needed for the additional 2.3 billion urban dwellers expected by the year 2050, then that would mean that the great cities could become sinks or repositories of stored carbon.

And new trees could grow in the space left by the harvested timber to add to the world inventory of stored carbon. The new towns and cities could become a kind of bank vault in which to save up to 700 million tonnes of carbon a year that might otherwise have spilled into the atmosphere as the greenhouse gas carbon dioxide.

“Since the beginning of the industrial revolution we have been releasing into the atmosphere all of this carbon that had been stored in forests and in the ground,” said Galina Churkina, of the Potsdam Institute for Climate Impact Research, Germany.

“We wanted to show that there can be a vision for returning much of this carbon back into the land.”

Strong fire-resistance

Wood is a fuel. It burns well. Paradoxically tree trunks, and treated timber assembled from laminates, do not. Structural timbers may char in a fire, but this has been shown to make them more resistant to burning. Experiment and research has shown that buildings of engineered timber up to 18 stories in height can be resistant to fire.

In effect, atmospheric carbon, turned into high-strength wood fibre by photosynthesis, could be made as safe as reinforced concrete. But, according to a new study in the journal Nature Sustainability, in 2014 the making of cement spilled 1,320 million tonnes of carbon dioxide into the atmosphere and steel manufacture added another 1,740 million tonnes.

And between 2005 and 2015, mining in Brazil alone was responsible for 9% of the loss of all Amazon forest land during that decade: the act of prospecting for or extracting mineral commodities destroyed 12 times more than the areas stipulated in the mining leases.

The Potsdam scientists are not the first to suggest wood as an alternative to bricks and mortar, or bamboo as a replacement for cement, steel and glass. But their analysis may be the most detailed so far of a new way to confront the challenge of tomorrow’s climate-tested cities.

The researchers built a series of scenarios to test their hypothesis. New city structures must be built to accommodate an additional million or more humans every week for the next three decades. The proportion now expected to be fashioned from timber is half of 1%.

“Trees offer us a technology of unparalleled perfection. If we engineer the wood into modern building materials we humans can build ourselves a safe home on Earth”

A five-storey house made from laminated timber could store 180 kilos of carbon a square meter: that is three times the biomass above ground in natural forests. If construction from wood was stepped up to 10%, new construction could store 10 million tonnes of carbon a year; if the world switched to 90% this figure could rise to almost 700 million tonnes.

“Trees offer us a technology of unparalleled perfection,” said Hans Joachim Schellnhuber, a co-author of the study and a founder director of the Potsdam Institute.

“They take CO2 out of our atmosphere and smoothly transform it into oxygen for us to breathe and carbon in their trunks for us to use. There’s no safer way of storing carbon I can think of.

“Societies have made good use of wood for buildings for many centuries, yet now the challenge of climate stabilisation calls for a very serious upscaling. If we engineer the wood into modern building materials and smartly manage harvest and construction, we humans can build ourselves a safe home on Earth.” − Climate News Network

Climate heat means new wine from familiar places

Each great wine is a unique product of place and climate. Rising heat could force new wine into old, prized bottles from famous cellars.

LONDON, 30 January, 2020 – As global average temperatures rise, so does uncertainty for the world’s wine-growers – with new wine the likely result. The great Bordeaux region of France will survive – but only if it stops serving claret.

Burgundy will still value its vines, but these won’t produce the high-priced tipple that the law defines as burgundy. Instead, what comes out of the cellars of Beaune or the Cote d’Or will be more like the output now from the southern Rhone.

That is always supposing that the growers keep up with rising temperatures by choosing grape varieties more likely to flourish with climate heating. A new study by European, Canadian and US scientists suggests that, even if the world’s most prized vineyards do abandon the grape varieties that made them prized in the first place, they will still lose up to a quarter of the space now in cultivation.

And if they don’t, the great wine regions of Europe could say goodbye to half their vineyards altogether. Producers in cool climates – Germany, New Zealand and the Pacific Northwest – could avoid major losses, but they will be tempted to switch to later-ripening varieties.

“Wine is like the canary in the coal mine for climate change impacts on agriculture, because these grapes are so climate-sensitive”

In the United Kingdom, where until very lately any wine harvest has been a gamble, the terrain might become suitable for at least five new varieties. New Zealand’s range of grape choices could double.

But Burgundian growers might have to forego the famously temperamental pinot noir grape and switch to grenache, or mourvedre, known in Spain as monastrell. The vintners of St Emilion, Pomerol and Medoc could see their cabernet sauvignon and merlot varieties replaced by mourvedre, according to research in the Proceedings of the National Academy of Sciences.

In fact, Europe’s growers have already had several warnings: hot and dry summers are now, for France, the norm. Extreme summer temperatures take their toll not just of the yield on the vine, but also of the people who have to pick the grapes, and even of the oak trees that provide the bark for the corks in the finished product.

Temperatures have already risen by more than 1°C worldwide, and the cool region of Champagne could be about to lose its sparkle.

Medieval records

But the new study is about far more than just the high-priced product of high-status wine regions. There are more than 1000 varieties of the grape Vitis vinifera, many of them sensitive to specific temperature and rainfall conditions. Even more helpfully, scientists can call upon harvest records that date back to medieval times.

So the grape seemed a good proxy for all of agriculture: from apples to wheat, from bananas to brassicas, the world’s growers can call on a huge range of crop varieties to buffer them from the shock of climate change driven by ever-increasing use of fossil fuels and ever-greater emissions of greenhouse gases into the atmosphere.

“In some ways, wine is like the canary in the coal mine for climate change impacts on agriculture, because these grapes are so climate-sensitive,” said co-author Benjamin Cook, of the Lamont Doherty Earth Observatory at Columbia University in the US.

The scientists considered 11 kinds of cultivar and dates of budding, flowering and harvest matched to seasonal temperature records, and found that if global temperatures rise by 2°C – and there is every indication that they could rise by more than 3°C – at least 51% of current wine-growing regions could be wiped out.

Higher warmth difficulties

“These estimates however ignore important changes that growers can make,” said Elizabeth Wolkovich, of the University of British Columbia, another author.

“We found that by switching to different varieties, vintners can lessen the damage to just 24% of areas lost. For example, in Burgundy, France, vintners can consider planting more heat-tolerant varieties such as syrah and grenache to replace the dominant pinot noir. And growers in regions such as Bordeaux may swap out cabernet sauvignon and merlot for mourvedre.”

But that’s if warming is limited to just 2°C. “At four degrees, around 77% of all areas may be lost, and planting new varieties will limit this to 58% losses,” said Ignacio Morales-Castilla, of the University of Acalá in Spain, who led the study.

“Wine-growing regions can adapt to a lower level of warming but at higher warming, it’s much harder.” – Climate News Network

Each great wine is a unique product of place and climate. Rising heat could force new wine into old, prized bottles from famous cellars.

LONDON, 30 January, 2020 – As global average temperatures rise, so does uncertainty for the world’s wine-growers – with new wine the likely result. The great Bordeaux region of France will survive – but only if it stops serving claret.

Burgundy will still value its vines, but these won’t produce the high-priced tipple that the law defines as burgundy. Instead, what comes out of the cellars of Beaune or the Cote d’Or will be more like the output now from the southern Rhone.

That is always supposing that the growers keep up with rising temperatures by choosing grape varieties more likely to flourish with climate heating. A new study by European, Canadian and US scientists suggests that, even if the world’s most prized vineyards do abandon the grape varieties that made them prized in the first place, they will still lose up to a quarter of the space now in cultivation.

And if they don’t, the great wine regions of Europe could say goodbye to half their vineyards altogether. Producers in cool climates – Germany, New Zealand and the Pacific Northwest – could avoid major losses, but they will be tempted to switch to later-ripening varieties.

“Wine is like the canary in the coal mine for climate change impacts on agriculture, because these grapes are so climate-sensitive”

In the United Kingdom, where until very lately any wine harvest has been a gamble, the terrain might become suitable for at least five new varieties. New Zealand’s range of grape choices could double.

But Burgundian growers might have to forego the famously temperamental pinot noir grape and switch to grenache, or mourvedre, known in Spain as monastrell. The vintners of St Emilion, Pomerol and Medoc could see their cabernet sauvignon and merlot varieties replaced by mourvedre, according to research in the Proceedings of the National Academy of Sciences.

In fact, Europe’s growers have already had several warnings: hot and dry summers are now, for France, the norm. Extreme summer temperatures take their toll not just of the yield on the vine, but also of the people who have to pick the grapes, and even of the oak trees that provide the bark for the corks in the finished product.

Temperatures have already risen by more than 1°C worldwide, and the cool region of Champagne could be about to lose its sparkle.

Medieval records

But the new study is about far more than just the high-priced product of high-status wine regions. There are more than 1000 varieties of the grape Vitis vinifera, many of them sensitive to specific temperature and rainfall conditions. Even more helpfully, scientists can call upon harvest records that date back to medieval times.

So the grape seemed a good proxy for all of agriculture: from apples to wheat, from bananas to brassicas, the world’s growers can call on a huge range of crop varieties to buffer them from the shock of climate change driven by ever-increasing use of fossil fuels and ever-greater emissions of greenhouse gases into the atmosphere.

“In some ways, wine is like the canary in the coal mine for climate change impacts on agriculture, because these grapes are so climate-sensitive,” said co-author Benjamin Cook, of the Lamont Doherty Earth Observatory at Columbia University in the US.

The scientists considered 11 kinds of cultivar and dates of budding, flowering and harvest matched to seasonal temperature records, and found that if global temperatures rise by 2°C – and there is every indication that they could rise by more than 3°C – at least 51% of current wine-growing regions could be wiped out.

Higher warmth difficulties

“These estimates however ignore important changes that growers can make,” said Elizabeth Wolkovich, of the University of British Columbia, another author.

“We found that by switching to different varieties, vintners can lessen the damage to just 24% of areas lost. For example, in Burgundy, France, vintners can consider planting more heat-tolerant varieties such as syrah and grenache to replace the dominant pinot noir. And growers in regions such as Bordeaux may swap out cabernet sauvignon and merlot for mourvedre.”

But that’s if warming is limited to just 2°C. “At four degrees, around 77% of all areas may be lost, and planting new varieties will limit this to 58% losses,” said Ignacio Morales-Castilla, of the University of Acalá in Spain, who led the study.

“Wine-growing regions can adapt to a lower level of warming but at higher warming, it’s much harder.” – Climate News Network