Author: Tim Radford

About Tim Radford

Tim Radford, a founding editor of Climate News Network, worked for The Guardian for 32 years, for most of that time as science editor. He has been covering climate change since 1988.

Warming oceans deter more fish from spawning

When the moment to mate arrives, fish like to play it cool. So warming oceans create special problems for the generation game.

LONDON, 9 July, 2020 – German scientists now know why so many fish are so vulnerable to ever-warming oceans. Global heating imposes a harsh cost at the most critical time of all: the moment of spawning.

“Our findings show that, both as embryos in eggs and as adults ready to mate, fish are far more sensitive to heat than in their larval stage or as sexually mature adults outside the mating season,” said Flemming Dahlke, a marine biologist with the Alfred Wegener Institute at Bremerhaven.

“On the global average, for example, adults outside the mating season can survive in water that’s up to 10°C warmer than adults ready to mate, or fish eggs, can.”

The finding – if it is confirmed by other research – should clear up some of the puzzles associated with fish numbers. There is clear evidence, established repeatedly over the decades, that fish are responding to climate change.

But almost three fourths of the planet is blue ocean, and at depth is responding far more slowly than the land surface to global heating fuelled by fossil fuel exploitation that releases greenhouse gases.

Nearing the brink

Since fish in the temperate zones already experience a wide variation in seasonal water temperatures, it hasn’t been obvious why species such as cod have shifted nearer the Arctic, and sardines have migrated to the North Sea.

But marine creatures are on the move, and although there are other factors at work, including overfishing and the increasingly alarming changes in ocean chemistry, thanks to ever-higher levels of dissolved carbon dioxide, temperature change is part of the problem.

The latest answer, Dr Dahlke and his colleagues report in the journal Science, is that many fish may already be living near the limits of their thermal tolerance.

The temperature safety margins during the moments of spawning and embryo might be very precise, and over hundreds of thousands of years of evolution, marine and freshwater species have worked out just what is best for the next generation. Rapid global warming upsets this equilibrium.

“Adults outside the mating season can survive in water that’s up to 10°C warmer than adults ready to mate, or fish eggs, can”

The Bremerhaven scientists looked at experiments, observations and recorded data for the life cycles of 694 marine and freshwater species, to decide that oxygen supply is the key decider of reproductive success. Warmer waters carry less dissolved oxygen. Embryo fish have no gills: they cannot simply take in deeper breaths.

Fish about to mate are busy producing extra mass in the form of sperm and egg cells: this additional body mass also needs oxygen. Even at lower temperatures, piscine cardiovascular systems are under stress.

So the reasoning follows that, if global heating continues, climate change and rising water temperatures are likely to affect the reproduction of perhaps 60% of all fish species.

“Some species might successfully manage this change,” Dr Dahlke said.
“But if you consider the fact that fish have adapted their mating patterns to specific habitats over extremely long timeframes, and have tailored their mating cycles of specific ocean currents and food sources, it has to be assumed that being forced to abandon their normal spawning areas will mean major problems for them.” – Climate News Network

When the moment to mate arrives, fish like to play it cool. So warming oceans create special problems for the generation game.

LONDON, 9 July, 2020 – German scientists now know why so many fish are so vulnerable to ever-warming oceans. Global heating imposes a harsh cost at the most critical time of all: the moment of spawning.

“Our findings show that, both as embryos in eggs and as adults ready to mate, fish are far more sensitive to heat than in their larval stage or as sexually mature adults outside the mating season,” said Flemming Dahlke, a marine biologist with the Alfred Wegener Institute at Bremerhaven.

“On the global average, for example, adults outside the mating season can survive in water that’s up to 10°C warmer than adults ready to mate, or fish eggs, can.”

The finding – if it is confirmed by other research – should clear up some of the puzzles associated with fish numbers. There is clear evidence, established repeatedly over the decades, that fish are responding to climate change.

But almost three fourths of the planet is blue ocean, and at depth is responding far more slowly than the land surface to global heating fuelled by fossil fuel exploitation that releases greenhouse gases.

Nearing the brink

Since fish in the temperate zones already experience a wide variation in seasonal water temperatures, it hasn’t been obvious why species such as cod have shifted nearer the Arctic, and sardines have migrated to the North Sea.

But marine creatures are on the move, and although there are other factors at work, including overfishing and the increasingly alarming changes in ocean chemistry, thanks to ever-higher levels of dissolved carbon dioxide, temperature change is part of the problem.

The latest answer, Dr Dahlke and his colleagues report in the journal Science, is that many fish may already be living near the limits of their thermal tolerance.

The temperature safety margins during the moments of spawning and embryo might be very precise, and over hundreds of thousands of years of evolution, marine and freshwater species have worked out just what is best for the next generation. Rapid global warming upsets this equilibrium.

“Adults outside the mating season can survive in water that’s up to 10°C warmer than adults ready to mate, or fish eggs, can”

The Bremerhaven scientists looked at experiments, observations and recorded data for the life cycles of 694 marine and freshwater species, to decide that oxygen supply is the key decider of reproductive success. Warmer waters carry less dissolved oxygen. Embryo fish have no gills: they cannot simply take in deeper breaths.

Fish about to mate are busy producing extra mass in the form of sperm and egg cells: this additional body mass also needs oxygen. Even at lower temperatures, piscine cardiovascular systems are under stress.

So the reasoning follows that, if global heating continues, climate change and rising water temperatures are likely to affect the reproduction of perhaps 60% of all fish species.

“Some species might successfully manage this change,” Dr Dahlke said.
“But if you consider the fact that fish have adapted their mating patterns to specific habitats over extremely long timeframes, and have tailored their mating cycles of specific ocean currents and food sources, it has to be assumed that being forced to abandon their normal spawning areas will mean major problems for them.” – Climate News Network

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

Less rain will fall during Mediterranean winters

Mediterranean winters could bring 40% less rain, hurting farmers in what’s called the cradle of agriculture – and not only farmers.

LONDON, 2 July, 2020 – A warmer world should also be a wetter one, but not for the cockpit of much of human history: Mediterranean winters will become increasingly parched. Winter rainfall – and winter is the rainy season – could see a 40% fall in precipitation.

Agriculture and human civilisation began in the Fertile Crescent that runs from eastern Turkey to Iraq: cattle, sheep and goats were domesticated there; the first figs, almonds, grapes and pulses were planted there; the progenitors of wheat were sown there.

Cities were built, irrigation schemes devised, empires rose and fell. Greece colonised the Mediterranean, Rome later controlled it and set the pattern of law and civic government for the next 2000 years in Northern Europe.

Islamic forces brought a different civilisation to the Balkans, North Africa and almost all of Spain. The grain fields of the Nile Valley underwrote the expansion of the Roman Empire.

“What’s really different about the Mediterranean is the geography. You have a big sea enclosed by continents, which doesn’t really occur anywhere else in the world”

But the pressure of history is likely to be affected by the high pressure of summers to come. In a world of rapid climate change, the already dry and sunny enclosed sea will become sunnier and drier, according to two scientists from the Massachusetts Institute of Technology.

They report in the American Meteorological Society’s Journal of Climate that the winter rains that are normally expected to fill the reservoirs and nourish the rich annual harvest from the orchards, vineyards and wheat fields can be expected to diminish significantly, as atmospheric pressures rise, to reduce rainfall by somewhere between 10% and 60%.

Ordinarily, a warmer world should be a wetter one. More water evaporates, and with each degree-rise in temperature the capacity of the air to hold water vapour increases by 7%, to fall inevitably as rain, somewhere.

But episodes of low pressure associated with rain clouds over the Mediterranean become less likely, according to climate simulations. The topography of the landscape and sea determines the probable pattern of the winds.

High pressure grows

“It just happened that the geography of where the Mediterranean is, and where the mountains are, impacts the pattern of air flow high in the atmosphere in a way that creates a high-pressure area over the Mediterranean,” said Alexandre Tuel, one of the authors.

“What’s really different about the Mediterranean compared to other regions is the geography. Basically, you have a big sea enclosed by continents, which doesn’t really occur anywhere else in the world.”

Another factor is the rate of warming: land warms faster than sea. The North African seaboard and the southern fringe of Europe will become 3 to 4°C hotter over the next hundred years. The sea will warm by only 2°C. The difference between land and sea will become smaller, to add to the pattern of high pressure circulation.

“Basically, the difference between the water and the land becomes smaller with time,” Tuel says.

Frequent warnings

Once again, the finding is no surprise: Europe has a long history of drought and flood, but drought tends to leave the more permanent mark. The eastern Mediterranean has already experienced its harshest drought for 900 years and this has been linked to the bitter conflict in Syria.

Researchers have repeatedly warned that the pattern of drought on the continent is likely to intensify, and at considerable economic and human cost.

What is different is that the latest research offers detailed predictions of the nature of change, and identifies the regions likeliest to be worst hit. These include Morocco in north-west Africa, and the eastern Mediterranean of Turkey and the Levant.

“These are areas where we already detect declines in precipitation,” said Elfatih Eltahir, the senior author. “We document from the observed record of precipitation that this eastern part has already experienced a significant decline of precipitation.” – Climate News Network

Mediterranean winters could bring 40% less rain, hurting farmers in what’s called the cradle of agriculture – and not only farmers.

LONDON, 2 July, 2020 – A warmer world should also be a wetter one, but not for the cockpit of much of human history: Mediterranean winters will become increasingly parched. Winter rainfall – and winter is the rainy season – could see a 40% fall in precipitation.

Agriculture and human civilisation began in the Fertile Crescent that runs from eastern Turkey to Iraq: cattle, sheep and goats were domesticated there; the first figs, almonds, grapes and pulses were planted there; the progenitors of wheat were sown there.

Cities were built, irrigation schemes devised, empires rose and fell. Greece colonised the Mediterranean, Rome later controlled it and set the pattern of law and civic government for the next 2000 years in Northern Europe.

Islamic forces brought a different civilisation to the Balkans, North Africa and almost all of Spain. The grain fields of the Nile Valley underwrote the expansion of the Roman Empire.

“What’s really different about the Mediterranean is the geography. You have a big sea enclosed by continents, which doesn’t really occur anywhere else in the world”

But the pressure of history is likely to be affected by the high pressure of summers to come. In a world of rapid climate change, the already dry and sunny enclosed sea will become sunnier and drier, according to two scientists from the Massachusetts Institute of Technology.

They report in the American Meteorological Society’s Journal of Climate that the winter rains that are normally expected to fill the reservoirs and nourish the rich annual harvest from the orchards, vineyards and wheat fields can be expected to diminish significantly, as atmospheric pressures rise, to reduce rainfall by somewhere between 10% and 60%.

Ordinarily, a warmer world should be a wetter one. More water evaporates, and with each degree-rise in temperature the capacity of the air to hold water vapour increases by 7%, to fall inevitably as rain, somewhere.

But episodes of low pressure associated with rain clouds over the Mediterranean become less likely, according to climate simulations. The topography of the landscape and sea determines the probable pattern of the winds.

High pressure grows

“It just happened that the geography of where the Mediterranean is, and where the mountains are, impacts the pattern of air flow high in the atmosphere in a way that creates a high-pressure area over the Mediterranean,” said Alexandre Tuel, one of the authors.

“What’s really different about the Mediterranean compared to other regions is the geography. Basically, you have a big sea enclosed by continents, which doesn’t really occur anywhere else in the world.”

Another factor is the rate of warming: land warms faster than sea. The North African seaboard and the southern fringe of Europe will become 3 to 4°C hotter over the next hundred years. The sea will warm by only 2°C. The difference between land and sea will become smaller, to add to the pattern of high pressure circulation.

“Basically, the difference between the water and the land becomes smaller with time,” Tuel says.

Frequent warnings

Once again, the finding is no surprise: Europe has a long history of drought and flood, but drought tends to leave the more permanent mark. The eastern Mediterranean has already experienced its harshest drought for 900 years and this has been linked to the bitter conflict in Syria.

Researchers have repeatedly warned that the pattern of drought on the continent is likely to intensify, and at considerable economic and human cost.

What is different is that the latest research offers detailed predictions of the nature of change, and identifies the regions likeliest to be worst hit. These include Morocco in north-west Africa, and the eastern Mediterranean of Turkey and the Levant.

“These are areas where we already detect declines in precipitation,” said Elfatih Eltahir, the senior author. “We document from the observed record of precipitation that this eastern part has already experienced a significant decline of precipitation.” – Climate News Network

Climate change caused havoc 2000 years ago

An Alaskan volcano once spurred climate change, darkening Mediterranean skies, launching a famine and possibly changing history.

LONDON, 1 July, 2020 – Once again, geologists have shown that climate change can be linked to some of the most dramatic moments in human history: civil strife in the Roman Republic that ended with the fall of a Greek dynasty in Egypt and the rise of the Roman Empire.

The summers just after the assassination of Julius Caesar in 44 BCE (Before the Christian Era) were among the coldest in the northern hemisphere for thousands of years, and this sudden prolonged chill can be linked to lost harvests, famine, the failure of the all-important Nile flood and the death of the Roman Mark Antony and the last of Egypt’s Ptolemaic rulers, Cleopatra.

The trigger for that cold shadow over the Mediterranean theatre of history? Summer and autumn temperatures fell to as much as 7°C below normal because on the far side of the hemisphere an Alaskan volcano erupted in 43 BCE to hurl colossal quantities of soot and sulphates into the stratosphere and dim the sun’s radiation for much of the next decade.

And the evidence? Deposits of volcanic ash in the Arctic ice cores that can be linked directly to one once-smoking crater in the Aleutian islands now known as Okmok, according to new research in the Proceedings of the National Academy of Sciences.

Average temperatures fell dramatically. Summer rainfall in southern Europe rose by 50% to 120% above normal. Autumn rainfall rose fourfold.

“To find a volcano on the other side of the Earth contributed to the demise of the Egyptians and the rise of the Roman Empire is fascinating”

The rest is history: literally. Roman and Chinese chronicles surviving from that time record what scientists call “unusual atmospheric phenomena” as well as “widespread famine.”

Less directly, records of lead pollution preserved in the annual layers of ice in Greenland tell a story of economic decline, reflected in what might be the reduction of mining and smelting of lead and silver during the last years of the Roman Republic.

And the effect on the hemisphere’s climate was also recorded in the annual flow and flood of the River Nile, a regular inundation that enriched the grain harvest of the Nile Valley, and supplied bread for Rome and its sister cities.

The research was led by Joe McConnell of the US Desert Research Institute in Nevada. “To find a volcano on the other side of the Earth erupted and effectively contributed to the demise of the Romans and the Egyptians and the rise of the Roman Empire is fascinating,” he said. “It certainly shows how interconnected the world was even 2000 years ago.”

And one of his co-authors, Joseph Manning of Yale University, said: “We know that the Nile River did not flood in 43 BCE and 42 BCE – and now we know why. The volcanic eruption greatly affected the Nile watershed.”

Climate’s role

That mass migration, conflict and the collapse of once-stable regimes can be linked to climate change is not news: researchers have repeatedly found that drought, cold and harvest failure can be matched with the collapse of ancient empires in the Middle East and in the Bronze Age Mediterranean.

Just 1500 years ago volcanic eruptions have been timed to the famine, the Plague of Justinian, and other turmoil in the Byzantine empire. Professor Manning had already linked a failure of the Nile flood to the collapse of the Ptolemaic dynasty in Egypt.

Neither the volcanic eruption nor the consequent climate disruption can be said to have “caused” ancient power struggles. But a backdrop of instability,  hunger and famine can be linked to conflict, and climate is now seen as an inseparable factor. Cold, heavy rain at the wrong season can ruin any harvest.

“In the Mediterranean region, these wet and extremely cold conditions during the agriculturally important spring through autumn seasons probably reduced crop yields and compounded supply problems during the ongoing political upheavals of the period,” said Andrew Wilson of the University of Oxford, another author.

“These findings lend credibility to reports of cold, famine, food shortage and disease described by ancient sources.” – Climate News Network

An Alaskan volcano once spurred climate change, darkening Mediterranean skies, launching a famine and possibly changing history.

LONDON, 1 July, 2020 – Once again, geologists have shown that climate change can be linked to some of the most dramatic moments in human history: civil strife in the Roman Republic that ended with the fall of a Greek dynasty in Egypt and the rise of the Roman Empire.

The summers just after the assassination of Julius Caesar in 44 BCE (Before the Christian Era) were among the coldest in the northern hemisphere for thousands of years, and this sudden prolonged chill can be linked to lost harvests, famine, the failure of the all-important Nile flood and the death of the Roman Mark Antony and the last of Egypt’s Ptolemaic rulers, Cleopatra.

The trigger for that cold shadow over the Mediterranean theatre of history? Summer and autumn temperatures fell to as much as 7°C below normal because on the far side of the hemisphere an Alaskan volcano erupted in 43 BCE to hurl colossal quantities of soot and sulphates into the stratosphere and dim the sun’s radiation for much of the next decade.

And the evidence? Deposits of volcanic ash in the Arctic ice cores that can be linked directly to one once-smoking crater in the Aleutian islands now known as Okmok, according to new research in the Proceedings of the National Academy of Sciences.

Average temperatures fell dramatically. Summer rainfall in southern Europe rose by 50% to 120% above normal. Autumn rainfall rose fourfold.

“To find a volcano on the other side of the Earth contributed to the demise of the Egyptians and the rise of the Roman Empire is fascinating”

The rest is history: literally. Roman and Chinese chronicles surviving from that time record what scientists call “unusual atmospheric phenomena” as well as “widespread famine.”

Less directly, records of lead pollution preserved in the annual layers of ice in Greenland tell a story of economic decline, reflected in what might be the reduction of mining and smelting of lead and silver during the last years of the Roman Republic.

And the effect on the hemisphere’s climate was also recorded in the annual flow and flood of the River Nile, a regular inundation that enriched the grain harvest of the Nile Valley, and supplied bread for Rome and its sister cities.

The research was led by Joe McConnell of the US Desert Research Institute in Nevada. “To find a volcano on the other side of the Earth erupted and effectively contributed to the demise of the Romans and the Egyptians and the rise of the Roman Empire is fascinating,” he said. “It certainly shows how interconnected the world was even 2000 years ago.”

And one of his co-authors, Joseph Manning of Yale University, said: “We know that the Nile River did not flood in 43 BCE and 42 BCE – and now we know why. The volcanic eruption greatly affected the Nile watershed.”

Climate’s role

That mass migration, conflict and the collapse of once-stable regimes can be linked to climate change is not news: researchers have repeatedly found that drought, cold and harvest failure can be matched with the collapse of ancient empires in the Middle East and in the Bronze Age Mediterranean.

Just 1500 years ago volcanic eruptions have been timed to the famine, the Plague of Justinian, and other turmoil in the Byzantine empire. Professor Manning had already linked a failure of the Nile flood to the collapse of the Ptolemaic dynasty in Egypt.

Neither the volcanic eruption nor the consequent climate disruption can be said to have “caused” ancient power struggles. But a backdrop of instability,  hunger and famine can be linked to conflict, and climate is now seen as an inseparable factor. Cold, heavy rain at the wrong season can ruin any harvest.

“In the Mediterranean region, these wet and extremely cold conditions during the agriculturally important spring through autumn seasons probably reduced crop yields and compounded supply problems during the ongoing political upheavals of the period,” said Andrew Wilson of the University of Oxford, another author.

“These findings lend credibility to reports of cold, famine, food shortage and disease described by ancient sources.” – 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

Ancient coal fires led to prehistoric extinctions

Did eruptions set ancient coal fires burning? Global heating happened 250 million years ago, just as it is happening now.

LONDON, 29 June, 2020 – Geologists have linked one of the planet’s most devastating events to the burning of fossil fuels, as ancient coal fires set in train a global extinction wave.

Emissions from the fires on a massive scale can be connected to catastrophic events that extinguished most of life on Earth – and this time, humans were not to blame.

It all happened more than 250 million years ago, at the close of the  Permian period. And this time the match that lit the flame was massive but slow volcanic eruption in what is now Siberia, a burning that continued for two million years.

In a new study in the US journal Geology, US, Canadian and Russian scientists report that in the course of six expeditions to collect rock samples from a formation known as the Siberian Traps they repeatedly found samples of charred wood and fragments of burnt coal.

“Our study shows that the Siberian Traps magmas combusted large quantities of coal and organic matter during eruption”

Geologists have identified five major extinctions of life in the past, and biologists now argue that – because of human action – a sixth has begun. But the worst of these was the Permian: the oceans acidified to lethal levels as carbon dioxide ratios in the atmosphere soared, and tropical ocean temperature reached fever pitch at 40°C.

Altogether, 96% of marine species disappeared, and 70% of land creatures. The event closed the Permian era, and ushered in the Triassic, and the beginning of the dinosaurs.

For geologists, the past is the key to the present: what happened once can happen again. And it now seems that the fuel that generated the high temperatures and acidic oceans was coal, laid down in the 50 million years of the Carboniferous that ended with the arrival of the Permian.

The Permian catastrophe has puzzled palaeontologists for decades, and the latest finding is not likely to be the end of the argument. Catastrophic climate change has been linked to most of the ancient extinctions. High carbon levels in the late Permian atmosphere have been implicated from the start.

Spur to action

Highly acidic seas – the oceans are the oldest, largest and richest of life’s habitats – have been named as prime suspect. Damage to the ancient ozone layer has also been cited. But in all cases, the cause of the sudden surge in atmospheric carbon has been up for debate: humans are implicated in climate change now. But what caused it then?

The answer: slowly slurping fiery magma (molten rock) from ancient volcanic sources, enough to cover 7 million square kilometres; enough to amount to 4 million cubic kilometres of once-smoking basalt that spilled over vast areas of old forest, buried peat and deeper fields of coal.

“Our study shows that the Siberian Traps magmas intruded into and incorporated coal and organic material. That gives us direct evidence that the magmas also combusted large quantities of coal and organic matter during eruption,” said Linda Elkins-Tanton, of Arizona State University, who led the research.

“Seeing these similarities gives us extra impetus to take action now, and also to further understand how the Earth responds to changes like these in the longer term.” – Climate News Network

Did eruptions set ancient coal fires burning? Global heating happened 250 million years ago, just as it is happening now.

LONDON, 29 June, 2020 – Geologists have linked one of the planet’s most devastating events to the burning of fossil fuels, as ancient coal fires set in train a global extinction wave.

Emissions from the fires on a massive scale can be connected to catastrophic events that extinguished most of life on Earth – and this time, humans were not to blame.

It all happened more than 250 million years ago, at the close of the  Permian period. And this time the match that lit the flame was massive but slow volcanic eruption in what is now Siberia, a burning that continued for two million years.

In a new study in the US journal Geology, US, Canadian and Russian scientists report that in the course of six expeditions to collect rock samples from a formation known as the Siberian Traps they repeatedly found samples of charred wood and fragments of burnt coal.

“Our study shows that the Siberian Traps magmas combusted large quantities of coal and organic matter during eruption”

Geologists have identified five major extinctions of life in the past, and biologists now argue that – because of human action – a sixth has begun. But the worst of these was the Permian: the oceans acidified to lethal levels as carbon dioxide ratios in the atmosphere soared, and tropical ocean temperature reached fever pitch at 40°C.

Altogether, 96% of marine species disappeared, and 70% of land creatures. The event closed the Permian era, and ushered in the Triassic, and the beginning of the dinosaurs.

For geologists, the past is the key to the present: what happened once can happen again. And it now seems that the fuel that generated the high temperatures and acidic oceans was coal, laid down in the 50 million years of the Carboniferous that ended with the arrival of the Permian.

The Permian catastrophe has puzzled palaeontologists for decades, and the latest finding is not likely to be the end of the argument. Catastrophic climate change has been linked to most of the ancient extinctions. High carbon levels in the late Permian atmosphere have been implicated from the start.

Spur to action

Highly acidic seas – the oceans are the oldest, largest and richest of life’s habitats – have been named as prime suspect. Damage to the ancient ozone layer has also been cited. But in all cases, the cause of the sudden surge in atmospheric carbon has been up for debate: humans are implicated in climate change now. But what caused it then?

The answer: slowly slurping fiery magma (molten rock) from ancient volcanic sources, enough to cover 7 million square kilometres; enough to amount to 4 million cubic kilometres of once-smoking basalt that spilled over vast areas of old forest, buried peat and deeper fields of coal.

“Our study shows that the Siberian Traps magmas intruded into and incorporated coal and organic material. That gives us direct evidence that the magmas also combusted large quantities of coal and organic matter during eruption,” said Linda Elkins-Tanton, of Arizona State University, who led the research.

“Seeing these similarities gives us extra impetus to take action now, and also to further understand how the Earth responds to changes like these in the longer term.” – Climate News Network

The wetter world ahead will suffer worse droughts

Things are bad now, but worse droughts are coming. More rain will fall in a warmer world, but not where and when we need it.

LONDON, 26 June, 2020 – Australian scientists have bad news for drought-stricken and fire-ravaged fellow-citizens: still worse droughts are in store.

Even though the world will grow wetter as greenhouse gas emissions rise and planetary average temperatures soar, the droughts will endure for longer and become more intense.

And this will be true not just for a country with a government that seems anxious not to acknowledge the role of climate change in a procession of disasters. It will be true for California and much of the US West. It will be true for the Mediterranean and parts of Africa, and for any areas that lie within the drylands zone.

It could be true even for the tropical rainforests. Wherever average rainfall seems to be in decline, droughts will become more devastating. And that includes Central America and the Amazon.

“The earlier we act on reducing our emissions, the less economic and social pain we will feel in the future”

And even in the rainy zones where precipitation seems to be on the rise, and floods more frequent, when droughts happen they will be more intense, according to new research in the journal Geophysical Research Letters.

The conclusion, although alarming, is not new. It reinforces decades of earlier research predicting that as the world warms floods, superstorms and megadroughts could all increase.

Every rise of 1°C in planetary average temperatures means that the atmosphere’s capacity to absorb water vapour also increases: for every 1°C rise, rainfall will increase by 2%, and with every average increase the extremes will become ever more extreme.

The latest finding is a test of new climate models to be used by the Intergovernmental Panel on Climate Change (IPCC). Between 1998 and 2017, according to UN data, droughts have afflicted 1.5bn people and accounted for a third of all natural disaster impacts.

Search for precision

What will happen as humans go on burning ever more fossil fuels to raise planetary average temperatures ever higher will mean ever more severe tests for farmers, pastoralists, industry, natural ecosystems and national economies.

The latest study is an attempt to be a little more precise about the shape of the future in a warming world.

“We found the new models produced the most robust results for future droughts to date and that the degree of increase in drought duration and intensity was directly linked to the amounts of greenhouse gases emitted into the atmosphere,” said Anna Ukkola of the Australian National University in Canberra, who led the study.

“However, while these insights grow clearer with each advance, the message they deliver remains the same – the earlier we act on reducing our emissions, the less economic and social pain we will feel in the future.” – Climate News Network

Things are bad now, but worse droughts are coming. More rain will fall in a warmer world, but not where and when we need it.

LONDON, 26 June, 2020 – Australian scientists have bad news for drought-stricken and fire-ravaged fellow-citizens: still worse droughts are in store.

Even though the world will grow wetter as greenhouse gas emissions rise and planetary average temperatures soar, the droughts will endure for longer and become more intense.

And this will be true not just for a country with a government that seems anxious not to acknowledge the role of climate change in a procession of disasters. It will be true for California and much of the US West. It will be true for the Mediterranean and parts of Africa, and for any areas that lie within the drylands zone.

It could be true even for the tropical rainforests. Wherever average rainfall seems to be in decline, droughts will become more devastating. And that includes Central America and the Amazon.

“The earlier we act on reducing our emissions, the less economic and social pain we will feel in the future”

And even in the rainy zones where precipitation seems to be on the rise, and floods more frequent, when droughts happen they will be more intense, according to new research in the journal Geophysical Research Letters.

The conclusion, although alarming, is not new. It reinforces decades of earlier research predicting that as the world warms floods, superstorms and megadroughts could all increase.

Every rise of 1°C in planetary average temperatures means that the atmosphere’s capacity to absorb water vapour also increases: for every 1°C rise, rainfall will increase by 2%, and with every average increase the extremes will become ever more extreme.

The latest finding is a test of new climate models to be used by the Intergovernmental Panel on Climate Change (IPCC). Between 1998 and 2017, according to UN data, droughts have afflicted 1.5bn people and accounted for a third of all natural disaster impacts.

Search for precision

What will happen as humans go on burning ever more fossil fuels to raise planetary average temperatures ever higher will mean ever more severe tests for farmers, pastoralists, industry, natural ecosystems and national economies.

The latest study is an attempt to be a little more precise about the shape of the future in a warming world.

“We found the new models produced the most robust results for future droughts to date and that the degree of increase in drought duration and intensity was directly linked to the amounts of greenhouse gases emitted into the atmosphere,” said Anna Ukkola of the Australian National University in Canberra, who led the study.

“However, while these insights grow clearer with each advance, the message they deliver remains the same – the earlier we act on reducing our emissions, the less economic and social pain we will feel in the future.” – Climate News Network

Nature’s accounts show what the world does for us

People go on getting richer, and the planet pays a mounting price. There’s a better way to balance nature’s accounts.

LONDON, 24 June, 2020 – It may take a while to catch on, but one day the financial pages of the daily newspaper could be quoting a new register of national wealth: called gross ecosystem product, this way of balancing nature’s accounts makes clear how much we really depend on the Earth.

And it would be a real-world indicator of prosperity you could have confidence in: a measure in cash terms of the health of the forests, rivers, lakes and wildlife of both nations and regions and – more precisely – of the benefits heedless humans take for granted.

These include the insect pollination of crops; the control of insect pests by birds and bats; the supply of fresh, safe water from mountain streams, rivers, springs and lakes; the management of waste by scavengers and microbes; the recycling of nutrients; and all the myriad services provided by plants, animals and topography. This is sometimes called “natural capital.”

The measure has already formally been tested in one province in China and matched with the more familiar indicator: Gross Domestic Product, or GDP.

Flying blind

Chinese scientists report in the Proceedings of the National Academy of Sciences that in the year 2000, the gross ecosystem product or GEP of Qinghai province was greater than its GDP.

By 2015, after phenomenal economic growth, it was still three-fourths the size of its GDP. And the form this natural wealth took? Mostly water supplies to other crowded regions: Qinghai is where the Mekong, the Yangtze and the Yellow Rivers rise.

“We’re basically flying blind when it comes to knowing where and how much nature to protect,” said Gretchen Daily, an environmental scientist at Stanford’s School of Humanities and Sciences in California, and one of the report’s authors.

“GEP tracks the vital contributions of nature to society, informs investments in securing them and helps evaluate the performance of leaders and policies.”

And her British co-author, Ian Bateman, an economist at the University of Exeter, said: “The global economy as conventionally measured by GDP more than doubled between 1990 and 2015. However, at the same time our stocks of ‘ecosystem assets’ – such as forests, grasslands, wetlands, fertile soils and biodiversity – have come under increasing pressure.”

“We were able to place a value on important ecosystem services, especially water supply, that Qinghai currently exports to other provinces but receives no credit for in the GDP calculation”

He continued: “These things are obviously valuable in many ways – including to human wellbeing. However, in this study we examine the benefits they bring us measured in a way that governments and business can understand.”

Naturalists, conservationists and economists have repeatedly argued that it makes better economic sense to conserve nature rather than to exploit it: untouched natural forest or grassland contributes more to everybody’s wealth than any clear-felling project or conversion to cattle-grazing.

Scientists and economists have again and again tried to calculate the cash value to humankind of nature’s goods and services, and to steer development in a sustainable fashion.

They have repeatedly warned that global heating driven by profligate use of fossil fuels is almost certain to hit the pockets of the poorest most cruelly.

And they have warned that uncontrolled exploitation of once untouched natural forests, mangrove estuaries, grasslands, wetlands and coral reefs that precipitates mass extinction of species is certain to impoverish billions in the long run.

Direct test

But to persuade governments that natural capital represents an investment with measurable returns, economists need a standard global measure. GEP could be it.

The measure was tested directly in what is sometimes called the “water tower” of Asia. The logic is that if the people of that region care for their natural habitat, and people downstream benefit directly from that care, then those downstream should also contribute to the costs of care.

“Qinghai is rich in natural capital but its GDP alone does not reflect that value”, said the study’s lead author, Zhiyun Ouyang, of the Chinese Academy of Sciences.

“Using this new metric we were able to place a value on important ecosystem services, especially water supply, that Qinghai currently exports to other provinces but receives no credit for in the GDP calculation.” – Climate News Network

People go on getting richer, and the planet pays a mounting price. There’s a better way to balance nature’s accounts.

LONDON, 24 June, 2020 – It may take a while to catch on, but one day the financial pages of the daily newspaper could be quoting a new register of national wealth: called gross ecosystem product, this way of balancing nature’s accounts makes clear how much we really depend on the Earth.

And it would be a real-world indicator of prosperity you could have confidence in: a measure in cash terms of the health of the forests, rivers, lakes and wildlife of both nations and regions and – more precisely – of the benefits heedless humans take for granted.

These include the insect pollination of crops; the control of insect pests by birds and bats; the supply of fresh, safe water from mountain streams, rivers, springs and lakes; the management of waste by scavengers and microbes; the recycling of nutrients; and all the myriad services provided by plants, animals and topography. This is sometimes called “natural capital.”

The measure has already formally been tested in one province in China and matched with the more familiar indicator: Gross Domestic Product, or GDP.

Flying blind

Chinese scientists report in the Proceedings of the National Academy of Sciences that in the year 2000, the gross ecosystem product or GEP of Qinghai province was greater than its GDP.

By 2015, after phenomenal economic growth, it was still three-fourths the size of its GDP. And the form this natural wealth took? Mostly water supplies to other crowded regions: Qinghai is where the Mekong, the Yangtze and the Yellow Rivers rise.

“We’re basically flying blind when it comes to knowing where and how much nature to protect,” said Gretchen Daily, an environmental scientist at Stanford’s School of Humanities and Sciences in California, and one of the report’s authors.

“GEP tracks the vital contributions of nature to society, informs investments in securing them and helps evaluate the performance of leaders and policies.”

And her British co-author, Ian Bateman, an economist at the University of Exeter, said: “The global economy as conventionally measured by GDP more than doubled between 1990 and 2015. However, at the same time our stocks of ‘ecosystem assets’ – such as forests, grasslands, wetlands, fertile soils and biodiversity – have come under increasing pressure.”

“We were able to place a value on important ecosystem services, especially water supply, that Qinghai currently exports to other provinces but receives no credit for in the GDP calculation”

He continued: “These things are obviously valuable in many ways – including to human wellbeing. However, in this study we examine the benefits they bring us measured in a way that governments and business can understand.”

Naturalists, conservationists and economists have repeatedly argued that it makes better economic sense to conserve nature rather than to exploit it: untouched natural forest or grassland contributes more to everybody’s wealth than any clear-felling project or conversion to cattle-grazing.

Scientists and economists have again and again tried to calculate the cash value to humankind of nature’s goods and services, and to steer development in a sustainable fashion.

They have repeatedly warned that global heating driven by profligate use of fossil fuels is almost certain to hit the pockets of the poorest most cruelly.

And they have warned that uncontrolled exploitation of once untouched natural forests, mangrove estuaries, grasslands, wetlands and coral reefs that precipitates mass extinction of species is certain to impoverish billions in the long run.

Direct test

But to persuade governments that natural capital represents an investment with measurable returns, economists need a standard global measure. GEP could be it.

The measure was tested directly in what is sometimes called the “water tower” of Asia. The logic is that if the people of that region care for their natural habitat, and people downstream benefit directly from that care, then those downstream should also contribute to the costs of care.

“Qinghai is rich in natural capital but its GDP alone does not reflect that value”, said the study’s lead author, Zhiyun Ouyang, of the Chinese Academy of Sciences.

“Using this new metric we were able to place a value on important ecosystem services, especially water supply, that Qinghai currently exports to other provinces but receives no credit for in the GDP calculation.” – Climate News Network

Antarctic melting could bring a much hotter future

Antarctic melting can force sea ice retreat of 50 metres daily. CO2 levels are at their highest for 23 million years. Learn from the past.

LONDON, 23 June, 2020 – Antarctic melting starts with dramatic speed. Ice shelves during the sudden warm spell at the close of the last Ice Age retreated at up to 50 metres a day.

This finding is not based on climate simulations generated by computer algorithms. It is based on direct evidence left 12,000 years ago on the Antarctic sea floor by retreating ice.

The finding is an indirect indicator of how warm things could get – and how high sea levels could rise – as humans burn ever more fossil fuels and raise atmospheric greenhouse gas levels to ever higher ratios.

And as if to highlight the approaching climate catastrophe, a second and separate study finds that the measure of carbon dioxide in the atmosphere now is not just higher than at any time in human history or at any interval in the Ice Ages. It is the highest for at least 23 million years.

“Should climate change continue to weaken the ice shelves in the coming decades, we could see similar rates of retreat, with profound implications for global sea level rise”

British scientists report in the journal Science that they used an autonomous underwater vehicle (AUV), cruising at depth in the Weddell Sea, to read the pattern of the past preserved in ridges of the Antarctic seabed.

The original push for the expedition had been to search for the ship Endurance, commanded by the polar explorer Ernest Shackleton on his doomed voyage in 1914. The loss of the ship, crushed in the polar ice, and the rescue of his crew became one of the epic stories of maritime history.

The researchers did not find Endurance. But they did find an enduring record of past ice retreat.

Sea ice skirts about 75% of the continent’s coastline: when it melts it makes no difference to sea levels, but while it remains frozen it does serve the purpose of buttressing glacial flow from the high Antarctic interior. Brushed by increasingly warm air each summer, and swept by slowly warming ocean currents all year round, the ice shelves are thinning and retreating.

Tell-tale line

Underneath the ice, the research team’s robot submarine spotted wave-like ridges, each about a metre high and 20 to 25 metres apart: ridges formed at what had once been the grounding line – the point at which a grounded ice sheet starts to float, and evidence of ice rising and falling with the tides.

There are twelve hours between high tide and low, so by measuring the distance between the ridges, scientists could measure the pace of retreat at the end of the last Ice Age. It is estimated at 40 to 50 metres a day.

Right now, the fastest retreat measured from grounding lines in Antarctica is only about 1.6 kms a year. The implication is that it could get a lot faster.

“Should climate change continue to weaken the ice shelves in the coming decades, we could see similar rates of retreat, with profound implications for global sea level rise,” said Julian Dowdeswell, director of the Scott Polar Research Institute in Cambridge, who led the research.

Faster change ahead

Past warm periods are associated only with relatively modest rises in atmospheric carbon dioxide. Right now, researchers have repeatedly confirmed that the present increasingly rapid rise is the highest in the last 800,000 years.

Now a team from the US and Norway report in the journal Geology that they have measured past atmospheric carbon levels in fossil plants to establish that present day carbon levels are higher currently than at any time in the last 23 million years.

This means that – unless there are drastic steps to contain global warming – the retreat will become increasingly more rapid, and the rate of glacial flow towards the sea ever faster.

Were all the ice in Antarctica to melt, sea levels would rise by about 60 metres, completely submerging many of the world’s great cities. – Climate News Network

Antarctic melting can force sea ice retreat of 50 metres daily. CO2 levels are at their highest for 23 million years. Learn from the past.

LONDON, 23 June, 2020 – Antarctic melting starts with dramatic speed. Ice shelves during the sudden warm spell at the close of the last Ice Age retreated at up to 50 metres a day.

This finding is not based on climate simulations generated by computer algorithms. It is based on direct evidence left 12,000 years ago on the Antarctic sea floor by retreating ice.

The finding is an indirect indicator of how warm things could get – and how high sea levels could rise – as humans burn ever more fossil fuels and raise atmospheric greenhouse gas levels to ever higher ratios.

And as if to highlight the approaching climate catastrophe, a second and separate study finds that the measure of carbon dioxide in the atmosphere now is not just higher than at any time in human history or at any interval in the Ice Ages. It is the highest for at least 23 million years.

“Should climate change continue to weaken the ice shelves in the coming decades, we could see similar rates of retreat, with profound implications for global sea level rise”

British scientists report in the journal Science that they used an autonomous underwater vehicle (AUV), cruising at depth in the Weddell Sea, to read the pattern of the past preserved in ridges of the Antarctic seabed.

The original push for the expedition had been to search for the ship Endurance, commanded by the polar explorer Ernest Shackleton on his doomed voyage in 1914. The loss of the ship, crushed in the polar ice, and the rescue of his crew became one of the epic stories of maritime history.

The researchers did not find Endurance. But they did find an enduring record of past ice retreat.

Sea ice skirts about 75% of the continent’s coastline: when it melts it makes no difference to sea levels, but while it remains frozen it does serve the purpose of buttressing glacial flow from the high Antarctic interior. Brushed by increasingly warm air each summer, and swept by slowly warming ocean currents all year round, the ice shelves are thinning and retreating.

Tell-tale line

Underneath the ice, the research team’s robot submarine spotted wave-like ridges, each about a metre high and 20 to 25 metres apart: ridges formed at what had once been the grounding line – the point at which a grounded ice sheet starts to float, and evidence of ice rising and falling with the tides.

There are twelve hours between high tide and low, so by measuring the distance between the ridges, scientists could measure the pace of retreat at the end of the last Ice Age. It is estimated at 40 to 50 metres a day.

Right now, the fastest retreat measured from grounding lines in Antarctica is only about 1.6 kms a year. The implication is that it could get a lot faster.

“Should climate change continue to weaken the ice shelves in the coming decades, we could see similar rates of retreat, with profound implications for global sea level rise,” said Julian Dowdeswell, director of the Scott Polar Research Institute in Cambridge, who led the research.

Faster change ahead

Past warm periods are associated only with relatively modest rises in atmospheric carbon dioxide. Right now, researchers have repeatedly confirmed that the present increasingly rapid rise is the highest in the last 800,000 years.

Now a team from the US and Norway report in the journal Geology that they have measured past atmospheric carbon levels in fossil plants to establish that present day carbon levels are higher currently than at any time in the last 23 million years.

This means that – unless there are drastic steps to contain global warming – the retreat will become increasingly more rapid, and the rate of glacial flow towards the sea ever faster.

Were all the ice in Antarctica to melt, sea levels would rise by about 60 metres, completely submerging many of the world’s great cities. – Climate News Network