Tag Archives: Food

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

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

Threatened mangrove forests won’t protect coasts

Rising tides driven by global heating could swamp the mangrove forests – bad news for the natural world, and for humans.

LONDON, 17 June, 2020 – If sea levels go on rising at ever higher rates, then by 2050 the world’s mangrove forests could be obliterated, drowned by rising tides.

Mangrove forests cover between 140,000 and 200,000 square kilometres of the intertidal zones that fringe more than 100 tropical and subtropical countries, and have become among the richest ecosystems of the planet.

They are estimated to store at least 30 million tonnes of atmospheric carbon each year, and a couple of sq kms of this saltwater forest can harbour nursery space for what could become 100 tonnes of commercial fish catch every year.

They also provide shelter for a huge range of creatures, including an estimated 500 Bengal tigers in the vast Sundarbans mangrove forests along the Ganges-Brahmaputra delta.

And while most of the 80 or so species of mangrove tree can keep up with an annual sea level rise of around 5mm a year, they seem unlikely, on evidence from the past, to be able to survive a 10mm rise. Right now, the world is heading for the higher end of the scale.

Sheltering people

A second and separate study finds that, importantly for humans, along with coral reefs, the mangrove forests provide vital natural protection from tropical storms for 31 million very vulnerable people in North and Central America and the crowded archipelagos of Indonesia and the Philippines.

Researchers from Australia, China, Singapore and the US report in the journal Science that they looked at the evidence locked in the sediments in 78 locations from the last 10,000 years, to work out how mangrove forests have – through the millennia – responded to changes in sea level.

At the close of the last ice age, sea levels rose at 10mm a year and slowed to nearly stable conditions 4000 years ago.

In a high emissions scenario, by 2050 sea level rise would exceed 6mm: the scientists found a 90% probability that mangroves would not be able to grow fast enough to keep up. Nor – because of the development of coastal settlements worldwide – would the forests be able to shift inland.

“Simply put, it’s much cheaper to conserve a mangrove than build a sea wall”

“This research therefore highlights yet another compelling reason why countries must take urgent action to reduce carbon emissions,” said Benjamin Horton of Nanyang Technical University in Singapore., one of the researchers.

“Mangroves are among the most valuable of natural ecosystems, supporting coastal fisheries and biodiversity, while protecting shorelines from wave and storm attack across the tropics.”

As so often happens in research, confirmatory evidence of the importance of mangroves had been published only days earlier, in the Public Library of Science journal PLOS One.

US researchers found that – in the Gulf of Mexico and the Caribbean, off the coasts of east Africa and in the Indo-Pacific – a total of 30.9 million people lived in regions vulnerable to powerful tropical storms such as Typhoon Haiyan and Hurricane Harvey.

Of these, more than 8 million people were offered severe weather protection by shoreline mangrove forests and coral reefs, both of which absorb wave energy, reduce wave heights and keep coastal settlements safer.

Not enough protection

But only 38% of mangroves and 11% of coral reefs along the vulnerable coastlines are protected, they found.

A 100-metre screen of shoreline mangrove forest can reduce wave heights by as much as two-thirds. By 2100, coastal floods could be costing the world’s nations US$1 trillion a year in economic damage.

Geographers have argued for decades that natural protection is the most efficient way of saving lives and settlements from the storm surges and flooding associated with tropical cyclone extremes.

“Simply put”, said Holly Jones of Northern Illinois University, who led the research, “it’s much cheaper to conserve a mangrove than build a sea wall.” – Climate News Network

Rising tides driven by global heating could swamp the mangrove forests – bad news for the natural world, and for humans.

LONDON, 17 June, 2020 – If sea levels go on rising at ever higher rates, then by 2050 the world’s mangrove forests could be obliterated, drowned by rising tides.

Mangrove forests cover between 140,000 and 200,000 square kilometres of the intertidal zones that fringe more than 100 tropical and subtropical countries, and have become among the richest ecosystems of the planet.

They are estimated to store at least 30 million tonnes of atmospheric carbon each year, and a couple of sq kms of this saltwater forest can harbour nursery space for what could become 100 tonnes of commercial fish catch every year.

They also provide shelter for a huge range of creatures, including an estimated 500 Bengal tigers in the vast Sundarbans mangrove forests along the Ganges-Brahmaputra delta.

And while most of the 80 or so species of mangrove tree can keep up with an annual sea level rise of around 5mm a year, they seem unlikely, on evidence from the past, to be able to survive a 10mm rise. Right now, the world is heading for the higher end of the scale.

Sheltering people

A second and separate study finds that, importantly for humans, along with coral reefs, the mangrove forests provide vital natural protection from tropical storms for 31 million very vulnerable people in North and Central America and the crowded archipelagos of Indonesia and the Philippines.

Researchers from Australia, China, Singapore and the US report in the journal Science that they looked at the evidence locked in the sediments in 78 locations from the last 10,000 years, to work out how mangrove forests have – through the millennia – responded to changes in sea level.

At the close of the last ice age, sea levels rose at 10mm a year and slowed to nearly stable conditions 4000 years ago.

In a high emissions scenario, by 2050 sea level rise would exceed 6mm: the scientists found a 90% probability that mangroves would not be able to grow fast enough to keep up. Nor – because of the development of coastal settlements worldwide – would the forests be able to shift inland.

“Simply put, it’s much cheaper to conserve a mangrove than build a sea wall”

“This research therefore highlights yet another compelling reason why countries must take urgent action to reduce carbon emissions,” said Benjamin Horton of Nanyang Technical University in Singapore., one of the researchers.

“Mangroves are among the most valuable of natural ecosystems, supporting coastal fisheries and biodiversity, while protecting shorelines from wave and storm attack across the tropics.”

As so often happens in research, confirmatory evidence of the importance of mangroves had been published only days earlier, in the Public Library of Science journal PLOS One.

US researchers found that – in the Gulf of Mexico and the Caribbean, off the coasts of east Africa and in the Indo-Pacific – a total of 30.9 million people lived in regions vulnerable to powerful tropical storms such as Typhoon Haiyan and Hurricane Harvey.

Of these, more than 8 million people were offered severe weather protection by shoreline mangrove forests and coral reefs, both of which absorb wave energy, reduce wave heights and keep coastal settlements safer.

Not enough protection

But only 38% of mangroves and 11% of coral reefs along the vulnerable coastlines are protected, they found.

A 100-metre screen of shoreline mangrove forest can reduce wave heights by as much as two-thirds. By 2100, coastal floods could be costing the world’s nations US$1 trillion a year in economic damage.

Geographers have argued for decades that natural protection is the most efficient way of saving lives and settlements from the storm surges and flooding associated with tropical cyclone extremes.

“Simply put”, said Holly Jones of Northern Illinois University, who led the research, “it’s much cheaper to conserve a mangrove than build a sea wall.” – 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

Halve the farmland, save nature, feed the world

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Nature under threat

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

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

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

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

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

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

Climate benefits

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Nature under threat

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

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

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

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

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

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

Climate benefits

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

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

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

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

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

A second US Dust Bowl would hit world food stocks

When the US Great Plains are hit again by sustained drought, the world’s food stocks will feel the heat.

LONDON, 27 March, 2020 – The next time the fertile soils of North America turn to dust, the consequences will hit food stocks worldwide.

Within four years of a climate crisis of the kind that fired John Steinbeck’s 1939 masterpiece The Grapes of Wrath, the US would have consumed almost all its grain reserves.

And the ripple effects would be felt in all those countries to which America normally exports grain. That is because America feeds much of the world: in a good year, the US exports wheat with an energy value of more than 90 trillion kilocalories. The collapse of farmland into wasteland on the scale that inspired John Steinbeck could reduce this over a four-year period to around 50 trillion kcal.

Worldwide, global wheat reserves would fall by 31% in the first year, and four years on somewhere between 36 and 52 countries would have consumed three-fourths of their own reserves. Food prices would rise around the planet.

“In today’s system of global food trade, disruptions are not bound by borders. Shocks to production are expected to affect trade partners who depend on imports for their domestic food supply,” said Alison Heslin, a climate scientist at Columbia University in the US.

“Accessing food reserves can, for a time, buffer populations from trade-induced supply shortages, but as reserves deplete, people are at risk of food shortages”

“Our results remind us that mitigating climate risks requires accounting not only for the direct effects of climate change, like local extreme weather events, but also the climate impacts which travel through our interconnected system of global trade.”

By some time in the mid-century, most of the US will be between 1.5°C to 2°C warmer. Researchers have already warned that the border between the arid western states and the more fertile mid-western plains has shifted to the east.

There have been repeated warnings that as global average temperatures rise, in response to ever greater use of fossil fuels, the US will become increasingly vulnerable to climate extremes, including megadroughts. Drought is already becoming the “new normal” for Californians, and the fertility of the Great Plains is in any case vulnerable to human changes to a natural landscape.

A succession of droughts of the kind that turned the farmland of Kansas and Oklahoma into a devastated landscape, and turned thousands of Americans into climate refugees, would not necessarily now mean the onset of regional famine.

Dr Heslin and her colleagues report in the journal Frontiers in Sustainable Food Systems that they contemplated the likelihood of a four-year drought of the kind that created the notorious 1930s Dust Bowl, and then examined the possible impact on world trade systems.

Yields and nutrition affected

Just one such climate event could hit hard those nations that rely on food imports, but even the other great grain-producing countries – among them China, India, Iran, Canada, Russia, Morocco, Australia and Egypt – would see their reserves fall.

The climate crisis is in any case a threat to the world’s supper tables. There has been repeated evidence that food output will inevitably be at risk in a warming world. With higher temperatures, yields will be reduced and with higher atmospheric levels of carbon dioxide that warm the planet, nutrition levels of many staples are expected to fall.

The researchers factored in none of these things. They supposed that a climate catastrophe that paralleled the Dust Bowl era would occur only in the US, and found that, despite strain, the world’s markets could probably cope.

But other studies have repeatedly found that the potential for climate catastrophe and massive crop failure to strike in more than one region at any one time are increasing, with ominous consequences for world food security.

“In the context of food security, we show that accessing food reserves can, for a time, buffer populations from trade-induced supply shortages,” said Dr Heslin, “but as reserves deplete, people are at risk of food shortages.” – Climate News Network

When the US Great Plains are hit again by sustained drought, the world’s food stocks will feel the heat.

LONDON, 27 March, 2020 – The next time the fertile soils of North America turn to dust, the consequences will hit food stocks worldwide.

Within four years of a climate crisis of the kind that fired John Steinbeck’s 1939 masterpiece The Grapes of Wrath, the US would have consumed almost all its grain reserves.

And the ripple effects would be felt in all those countries to which America normally exports grain. That is because America feeds much of the world: in a good year, the US exports wheat with an energy value of more than 90 trillion kilocalories. The collapse of farmland into wasteland on the scale that inspired John Steinbeck could reduce this over a four-year period to around 50 trillion kcal.

Worldwide, global wheat reserves would fall by 31% in the first year, and four years on somewhere between 36 and 52 countries would have consumed three-fourths of their own reserves. Food prices would rise around the planet.

“In today’s system of global food trade, disruptions are not bound by borders. Shocks to production are expected to affect trade partners who depend on imports for their domestic food supply,” said Alison Heslin, a climate scientist at Columbia University in the US.

“Accessing food reserves can, for a time, buffer populations from trade-induced supply shortages, but as reserves deplete, people are at risk of food shortages”

“Our results remind us that mitigating climate risks requires accounting not only for the direct effects of climate change, like local extreme weather events, but also the climate impacts which travel through our interconnected system of global trade.”

By some time in the mid-century, most of the US will be between 1.5°C to 2°C warmer. Researchers have already warned that the border between the arid western states and the more fertile mid-western plains has shifted to the east.

There have been repeated warnings that as global average temperatures rise, in response to ever greater use of fossil fuels, the US will become increasingly vulnerable to climate extremes, including megadroughts. Drought is already becoming the “new normal” for Californians, and the fertility of the Great Plains is in any case vulnerable to human changes to a natural landscape.

A succession of droughts of the kind that turned the farmland of Kansas and Oklahoma into a devastated landscape, and turned thousands of Americans into climate refugees, would not necessarily now mean the onset of regional famine.

Dr Heslin and her colleagues report in the journal Frontiers in Sustainable Food Systems that they contemplated the likelihood of a four-year drought of the kind that created the notorious 1930s Dust Bowl, and then examined the possible impact on world trade systems.

Yields and nutrition affected

Just one such climate event could hit hard those nations that rely on food imports, but even the other great grain-producing countries – among them China, India, Iran, Canada, Russia, Morocco, Australia and Egypt – would see their reserves fall.

The climate crisis is in any case a threat to the world’s supper tables. There has been repeated evidence that food output will inevitably be at risk in a warming world. With higher temperatures, yields will be reduced and with higher atmospheric levels of carbon dioxide that warm the planet, nutrition levels of many staples are expected to fall.

The researchers factored in none of these things. They supposed that a climate catastrophe that paralleled the Dust Bowl era would occur only in the US, and found that, despite strain, the world’s markets could probably cope.

But other studies have repeatedly found that the potential for climate catastrophe and massive crop failure to strike in more than one region at any one time are increasing, with ominous consequences for world food security.

“In the context of food security, we show that accessing food reserves can, for a time, buffer populations from trade-induced supply shortages,” said Dr Heslin, “but as reserves deplete, people are at risk of food shortages.” – Climate News Network

Regional nuclear war could bring global hunger

Limited nuclear war could certainly slow planetary heating. But it could also cast a lethal wider chill, unleashing global hunger.

LONDON, 25 March, 2020 – If a limited nuclear war is not already a contradiction in terms, it could still prove far wider in scope, inflicting global hunger without limit.

US and European scientists have worked out how to dramatically lower planetary temperatures and reduce rainfall. They do not recommend their latest study of explosive geo-engineering as a way of addressing the climate crisis, warning instead that even a very limited nuclear war between two nations could devastate global harvests.

Just possibly, they say, it could claim more lives in the non-combatant nations than in the incinerated cities of the warring states.

“Our results add to the reasons that nuclear weapons must be eliminated because, if they exist, they can be used with tragic consequences for the world,” said Alan Robock of Rutgers University in the US.

“As horrible as the direct effects of nuclear weapons would be, more people could die outside the target areas due to famine.”

Hypothetical studies like this can help illustrate the vulnerability of world food stocks to climate change, the scale on which climate change can and may yet happen, and the difficulties inherent in any attempts at global technofix.

No winners

They also demonstrate that – for everybody on the planet – nuclear war of any kind could be a confrontation with no winners.

It is a given among climate scientists that violent volcanic eruptions which hurl sulphate aerosols and soot particles into the stratosphere can suppress global average temperatures over a period of years.

That is why, as greenhouse gas emissions from fossil fuel use build up in the atmosphere, and annual average global temperatures continue to climb, researchers repeatedly revisit the argument for deliberately and systematically darkening the skies to blot out some of the incoming sunlight and reduce global heating.

But again and again, scientists have used their war game models of potential nuclear battle to highlight the hazards of darkening the skies precipitately in a nuclear exchange.

The latest is published in the Proceedings of the National Academy of Sciences and calculates that any encounter that uses less than even 1% of the world’s nuclear arsenal could trigger the worst global food losses in modern history, and disrupt harvests and food trade worldwide for about a decade.

“Major breadbasket regions would cut exports, leaving countries worldwide short of supplies. A regional crisis would become global”

The impact of this would turn out to be even worse than the impact of human-made climate change by the end of the century.

“We now know that nuclear conflict would not be just a terrible tragedy in the region where it happens – it is also an underestimated risk for food security,” said Jonas Jägermeyr of Germany’s Potsdam Institute for Climate Impact Research.

“We find severe losses in agricultural production, but more importantly we evaluate trade repercussions affecting local food availability. It turns out that major breadbasket regions would cut exports, leaving countries worldwide short of supplies. A regional crisis would become global, because we all depend on the same climate system.”

The regional crisis, in this case, would be a nuclear exchange involving perhaps 100 Hiroshima-scale warheads over the most densely populated cities of India and Pakistan, neighbouring states with both nuclear weapons and a history of hostility.

The exchange could put five million tonnes of smoke and soot into the upper atmosphere, where the jet stream winds would start to sweep it around the hemisphere. Global average temperatures would drop by 1.8°C, and rainfall would be reduced by 8% for at least five years.

Fossil fuel combustion over the last two centuries has already warmed the planet by around 1°C, to threaten world harvests. But until now, nobody has calculated the cost of a sudden plunge in temperatures.

Four years to zero

The researchers did not factor in the losses in the combatant countries, nor the worldwide damage from radioactive fallout. They just considered the impact on all the other nations that stayed neutral.

In the first year, stocks of maize, wheat, rice and soy in the world’s granaries would buffer the immediate losses. But within four years, global grain stocks would be at almost zero and international trade systems would come to a stop.

Maize and wheat supplies would shrink by at least 20% in more than 70 countries, with about 1.3bn people. By the fourth year, 132 out of 153 countries, home to 5bn people, would experience shortages higher than 10%. Corn production in the US and Canada – source of 40% of all maize – would drop by 17.5% by the fifth year of darkened skies.

The scientists based their calculations on only 5 million tonnes of soot and ash in the stratosphere. In fact, a war between the two nations could yield 16 million tonnes of soot, and be three times as devastating.

And anyone who thinks that at least global warming would have been brought to a halt can think again. After about a decade, the researchers say, global temperatures would again start to surge. – Climate News Network

Limited nuclear war could certainly slow planetary heating. But it could also cast a lethal wider chill, unleashing global hunger.

LONDON, 25 March, 2020 – If a limited nuclear war is not already a contradiction in terms, it could still prove far wider in scope, inflicting global hunger without limit.

US and European scientists have worked out how to dramatically lower planetary temperatures and reduce rainfall. They do not recommend their latest study of explosive geo-engineering as a way of addressing the climate crisis, warning instead that even a very limited nuclear war between two nations could devastate global harvests.

Just possibly, they say, it could claim more lives in the non-combatant nations than in the incinerated cities of the warring states.

“Our results add to the reasons that nuclear weapons must be eliminated because, if they exist, they can be used with tragic consequences for the world,” said Alan Robock of Rutgers University in the US.

“As horrible as the direct effects of nuclear weapons would be, more people could die outside the target areas due to famine.”

Hypothetical studies like this can help illustrate the vulnerability of world food stocks to climate change, the scale on which climate change can and may yet happen, and the difficulties inherent in any attempts at global technofix.

No winners

They also demonstrate that – for everybody on the planet – nuclear war of any kind could be a confrontation with no winners.

It is a given among climate scientists that violent volcanic eruptions which hurl sulphate aerosols and soot particles into the stratosphere can suppress global average temperatures over a period of years.

That is why, as greenhouse gas emissions from fossil fuel use build up in the atmosphere, and annual average global temperatures continue to climb, researchers repeatedly revisit the argument for deliberately and systematically darkening the skies to blot out some of the incoming sunlight and reduce global heating.

But again and again, scientists have used their war game models of potential nuclear battle to highlight the hazards of darkening the skies precipitately in a nuclear exchange.

The latest is published in the Proceedings of the National Academy of Sciences and calculates that any encounter that uses less than even 1% of the world’s nuclear arsenal could trigger the worst global food losses in modern history, and disrupt harvests and food trade worldwide for about a decade.

“Major breadbasket regions would cut exports, leaving countries worldwide short of supplies. A regional crisis would become global”

The impact of this would turn out to be even worse than the impact of human-made climate change by the end of the century.

“We now know that nuclear conflict would not be just a terrible tragedy in the region where it happens – it is also an underestimated risk for food security,” said Jonas Jägermeyr of Germany’s Potsdam Institute for Climate Impact Research.

“We find severe losses in agricultural production, but more importantly we evaluate trade repercussions affecting local food availability. It turns out that major breadbasket regions would cut exports, leaving countries worldwide short of supplies. A regional crisis would become global, because we all depend on the same climate system.”

The regional crisis, in this case, would be a nuclear exchange involving perhaps 100 Hiroshima-scale warheads over the most densely populated cities of India and Pakistan, neighbouring states with both nuclear weapons and a history of hostility.

The exchange could put five million tonnes of smoke and soot into the upper atmosphere, where the jet stream winds would start to sweep it around the hemisphere. Global average temperatures would drop by 1.8°C, and rainfall would be reduced by 8% for at least five years.

Fossil fuel combustion over the last two centuries has already warmed the planet by around 1°C, to threaten world harvests. But until now, nobody has calculated the cost of a sudden plunge in temperatures.

Four years to zero

The researchers did not factor in the losses in the combatant countries, nor the worldwide damage from radioactive fallout. They just considered the impact on all the other nations that stayed neutral.

In the first year, stocks of maize, wheat, rice and soy in the world’s granaries would buffer the immediate losses. But within four years, global grain stocks would be at almost zero and international trade systems would come to a stop.

Maize and wheat supplies would shrink by at least 20% in more than 70 countries, with about 1.3bn people. By the fourth year, 132 out of 153 countries, home to 5bn people, would experience shortages higher than 10%. Corn production in the US and Canada – source of 40% of all maize – would drop by 17.5% by the fifth year of darkened skies.

The scientists based their calculations on only 5 million tonnes of soot and ash in the stratosphere. In fact, a war between the two nations could yield 16 million tonnes of soot, and be three times as devastating.

And anyone who thinks that at least global warming would have been brought to a halt can think again. After about a decade, the researchers say, global temperatures would again start to surge. – Climate News Network