Tag Archives: Drought

Global heating drives daily weather change

Expect the climate, but prepare for the weather? Not any more. The statistics spell it out: global heating is causing daily weather change.

LONDON, 6 January, 2020 – Swiss scientists have done something many of their colleagues had claimed was impossible: they have linked the random events of the daily weather change we all experience directly to the climate crisis.

It has been an axiom of climate science for decades that – although global heating would inevitably increase the likelihood of more intense or more damaging windstorms, floods, droughts or heat waves – it would not be possible to say that this or that event could not have happened the way it did without the ominous rise in global average temperature, driven by profligate use of fossil fuels.

But that no longer holds, according to a new study in the journal Nature Climate Change.

“Weather when considered globally is now in uncharted territory,” researchers write. “On the basis of a single day of globally observed temperature and moisture, we detect the fingerprint of externally driven climate change, and conclude that the earth as a whole is warming.”

Climate scientists and statisticians from the Swiss Federal Institute of Technology, known simply as ETH Zurich, and from a partner institute in Lausanne known as EPFL, say that the seemingly normal variations in daily weather around the world are telling a clear story – just as long as the observers look at the global picture as well as the local measurements.

Clear pattern

For instance, on the same day as the Swiss study the UK Met Office announced a set of new temperature records for Britain in the last decade. The coldest March day ever recorded was in Gwent, Wales, in March 2018, when the thermometer fell to minus 4.7°C. But during the same decade the rest of Britain experienced four new and unprecedented monthly high temperatures, including an as yet unverified high of 18.7°C late in December.

In January 2020, a village in Norway registered a high of 19°C, a whole 25 degrees above the average for the winter month. But whereas local temperatures can fluctuate wildly, the variation in global average data is very small.

The Swiss scientists combed through the daily mean temperature and rainfall and snowfall data for the years 1951 to 1980, and for 2009 to 2018. They drew bell-shaped curves for each sequence of the years and then tried to match them. Without any overall rise in average global temperatures, the two curves would cover much the same space on the graph paper. They barely overlapped.

They then used a range of sophisticated statistical techniques to make detailed sense of the information in the two patterns of decadal weather. Beyond the jargon of the statistician’s trade – the paper talks of regression coefficients and regularised linear regression models, mean squared errors and Pearson correlations – a clear pattern emerged.

“Weather when considered globally is now in uncharted territory”

The often-wild swings of natural variation could be disentangled from the intensification powered by global heating. Climate change could be detected from global weather in any single year, month or even day. No longer can climate researchers use the old escape clause, “Climate is what you expect, weather is what you get,” to explain away seeming seasonal inconsistencies.

Global heating driven by greenhouse gases released by human economic growth is now shaping the world’s daily weather, from the catastrophic heat extremes and wildfires in Australia to the uncharacteristic winter weather in Moscow.

“The fingerprint of climate change is detected from any single day in the observed global record since early 2012”, the scientists write, “and since 1999 on the basis of a year of data. Detection is robust even when ignoring the long-term global warming trend.” – Climate News Network

Expect the climate, but prepare for the weather? Not any more. The statistics spell it out: global heating is causing daily weather change.

LONDON, 6 January, 2020 – Swiss scientists have done something many of their colleagues had claimed was impossible: they have linked the random events of the daily weather change we all experience directly to the climate crisis.

It has been an axiom of climate science for decades that – although global heating would inevitably increase the likelihood of more intense or more damaging windstorms, floods, droughts or heat waves – it would not be possible to say that this or that event could not have happened the way it did without the ominous rise in global average temperature, driven by profligate use of fossil fuels.

But that no longer holds, according to a new study in the journal Nature Climate Change.

“Weather when considered globally is now in uncharted territory,” researchers write. “On the basis of a single day of globally observed temperature and moisture, we detect the fingerprint of externally driven climate change, and conclude that the earth as a whole is warming.”

Climate scientists and statisticians from the Swiss Federal Institute of Technology, known simply as ETH Zurich, and from a partner institute in Lausanne known as EPFL, say that the seemingly normal variations in daily weather around the world are telling a clear story – just as long as the observers look at the global picture as well as the local measurements.

Clear pattern

For instance, on the same day as the Swiss study the UK Met Office announced a set of new temperature records for Britain in the last decade. The coldest March day ever recorded was in Gwent, Wales, in March 2018, when the thermometer fell to minus 4.7°C. But during the same decade the rest of Britain experienced four new and unprecedented monthly high temperatures, including an as yet unverified high of 18.7°C late in December.

In January 2020, a village in Norway registered a high of 19°C, a whole 25 degrees above the average for the winter month. But whereas local temperatures can fluctuate wildly, the variation in global average data is very small.

The Swiss scientists combed through the daily mean temperature and rainfall and snowfall data for the years 1951 to 1980, and for 2009 to 2018. They drew bell-shaped curves for each sequence of the years and then tried to match them. Without any overall rise in average global temperatures, the two curves would cover much the same space on the graph paper. They barely overlapped.

They then used a range of sophisticated statistical techniques to make detailed sense of the information in the two patterns of decadal weather. Beyond the jargon of the statistician’s trade – the paper talks of regression coefficients and regularised linear regression models, mean squared errors and Pearson correlations – a clear pattern emerged.

“Weather when considered globally is now in uncharted territory”

The often-wild swings of natural variation could be disentangled from the intensification powered by global heating. Climate change could be detected from global weather in any single year, month or even day. No longer can climate researchers use the old escape clause, “Climate is what you expect, weather is what you get,” to explain away seeming seasonal inconsistencies.

Global heating driven by greenhouse gases released by human economic growth is now shaping the world’s daily weather, from the catastrophic heat extremes and wildfires in Australia to the uncharacteristic winter weather in Moscow.

“The fingerprint of climate change is detected from any single day in the observed global record since early 2012”, the scientists write, “and since 1999 on the basis of a year of data. Detection is robust even when ignoring the long-term global warming trend.” – Climate News Network

Jet stream changes may hit global breadbaskets

Food shortages and civil disturbances may result from changes in the jet stream winds which circle the Earth, scientists say.

LONDON, 10 December, 2019 − Patterns in the winds of the jet stream that circles the Earth can bring simultaneous heatwaves to breadbasket regions which provide up to a quarter of global crops, scientists have found.

Extreme weather on this scale can significantly harm food production, making prices soar and fuelling social unrest. Western North America, western Europe, western Russia, Ukraine and the Caspian Sea region are especially susceptible.

In a study published in the journal Nature Climate Change the researchers, from Germany, Australia and the US, explain how specific wave patterns in the jet stream strongly increase the chance of heatwaves occurring at the same time in different parts of the globe.

The jet stream is a fast-moving river of air that continuously circles the northern hemisphere from west to east. It generally confines itself to a relatively narrow band, but can meander north or south, due to a feature scientists call Rossby waves.

Among other effects, these atmospheric wobbles may pull frigid air masses from the polar regions, or hot ones from the subtropics, into the populous mid-latitudes.

“We will see more and more heatwaves striking different areas at the same time, and they will become even more severe”

The wobbles strongly influence daily weather. When they grow particularly large they can bring prolonged heatwaves, droughts or floods in summer, or in colder seasons abnormal cold spells.

The waves have hit in 1983, 2003, 2006, 2012 and 2018, when many temperature records fell across the US, Canada, Scandinavia and Siberia. As well as killing crops, the waves have killed thousands of people, especially in Europe and Russia, where air conditioning is far less common than in North America.

The research shows that there has been a significant increase in the probability of multiple global breadbasket failures, particularly for wheat, maize, and soybeans. For soybeans the implications of crop failure in all major breadbaskets associated with climate risk would be at least 12.55 million tons of crop losses, far more than the 7.2 million tons lost in 1988–1989, one of the largest soybean production shocks.

Kai Kornhuber, a doctoral candidate from the Potsdam Institute for Climate Impact Research (PIK) in Germany and the Lamont-Doherty Earth Institute, US, and colleagues found that it is these simultaneous heatwaves that can significantly reduce crop production and create the risk of multiple harvest failures and other far-reaching consequences.

Twentyfold increase

“We found an under-explored vulnerability in the food system: when these global-scale wind patterns are in place, we see a twenty-fold increase in the risk of simultaneous heatwaves in major crop-producing regions ”, said Kornhuber. “During these events there actually is a global structure in the otherwise quite chaotic circulation.”

The atmospheric patterns the team researched mean that heat and drought become locked into one place simultaneously, where they then affect crops’ production yields.

“What makes this particularly relevant: the bell can ring in multiple regions at once, and the impacts of those specific interconnections were not quantified previously,” Kornhuber said.

“Normally low harvests in one region are expected to be balanced out by good harvests elsewhere. But these waves can cause reduced harvests in several important breadbaskets simultaneously, creating risks for global food production”, said co-author Dr Dim Coumou from the Institute for Environmental Studies at VU Amsterdam and PIK.

Remote effects

“We will see more and more heatwaves striking different areas at the same time, and they will become even more severe”, added Dr Jonathan Donges, another co-author at PIK. “This can impact food availability not only in the regions directly affected. Even remoter regions may see scarcities and price spikes as a result.”

“During years in which two or more summer weeks featured the amplified wave pattern, cereal crop production was reduced by more than 10% in individual regions, and by 4% when averaged across all crop regions affected by the pattern”, said Elisabeth Vogel, from Melbourne University.

Ted Shepherd, professor of climate science at the University of Reading, UK, who was not involved in the study, said: “We have strong observational evidence of this wave pattern. What is open for discussion is how it might respond to climate change.”

Professor Shepherd said many consensus scientific statements, including those from the Intergovernmental Panel on Climate Change, had proved to be under-estimates of how fast and far the effects of global warming might move. − Climate News Network

Food shortages and civil disturbances may result from changes in the jet stream winds which circle the Earth, scientists say.

LONDON, 10 December, 2019 − Patterns in the winds of the jet stream that circles the Earth can bring simultaneous heatwaves to breadbasket regions which provide up to a quarter of global crops, scientists have found.

Extreme weather on this scale can significantly harm food production, making prices soar and fuelling social unrest. Western North America, western Europe, western Russia, Ukraine and the Caspian Sea region are especially susceptible.

In a study published in the journal Nature Climate Change the researchers, from Germany, Australia and the US, explain how specific wave patterns in the jet stream strongly increase the chance of heatwaves occurring at the same time in different parts of the globe.

The jet stream is a fast-moving river of air that continuously circles the northern hemisphere from west to east. It generally confines itself to a relatively narrow band, but can meander north or south, due to a feature scientists call Rossby waves.

Among other effects, these atmospheric wobbles may pull frigid air masses from the polar regions, or hot ones from the subtropics, into the populous mid-latitudes.

“We will see more and more heatwaves striking different areas at the same time, and they will become even more severe”

The wobbles strongly influence daily weather. When they grow particularly large they can bring prolonged heatwaves, droughts or floods in summer, or in colder seasons abnormal cold spells.

The waves have hit in 1983, 2003, 2006, 2012 and 2018, when many temperature records fell across the US, Canada, Scandinavia and Siberia. As well as killing crops, the waves have killed thousands of people, especially in Europe and Russia, where air conditioning is far less common than in North America.

The research shows that there has been a significant increase in the probability of multiple global breadbasket failures, particularly for wheat, maize, and soybeans. For soybeans the implications of crop failure in all major breadbaskets associated with climate risk would be at least 12.55 million tons of crop losses, far more than the 7.2 million tons lost in 1988–1989, one of the largest soybean production shocks.

Kai Kornhuber, a doctoral candidate from the Potsdam Institute for Climate Impact Research (PIK) in Germany and the Lamont-Doherty Earth Institute, US, and colleagues found that it is these simultaneous heatwaves that can significantly reduce crop production and create the risk of multiple harvest failures and other far-reaching consequences.

Twentyfold increase

“We found an under-explored vulnerability in the food system: when these global-scale wind patterns are in place, we see a twenty-fold increase in the risk of simultaneous heatwaves in major crop-producing regions ”, said Kornhuber. “During these events there actually is a global structure in the otherwise quite chaotic circulation.”

The atmospheric patterns the team researched mean that heat and drought become locked into one place simultaneously, where they then affect crops’ production yields.

“What makes this particularly relevant: the bell can ring in multiple regions at once, and the impacts of those specific interconnections were not quantified previously,” Kornhuber said.

“Normally low harvests in one region are expected to be balanced out by good harvests elsewhere. But these waves can cause reduced harvests in several important breadbaskets simultaneously, creating risks for global food production”, said co-author Dr Dim Coumou from the Institute for Environmental Studies at VU Amsterdam and PIK.

Remote effects

“We will see more and more heatwaves striking different areas at the same time, and they will become even more severe”, added Dr Jonathan Donges, another co-author at PIK. “This can impact food availability not only in the regions directly affected. Even remoter regions may see scarcities and price spikes as a result.”

“During years in which two or more summer weeks featured the amplified wave pattern, cereal crop production was reduced by more than 10% in individual regions, and by 4% when averaged across all crop regions affected by the pattern”, said Elisabeth Vogel, from Melbourne University.

Ted Shepherd, professor of climate science at the University of Reading, UK, who was not involved in the study, said: “We have strong observational evidence of this wave pattern. What is open for discussion is how it might respond to climate change.”

Professor Shepherd said many consensus scientific statements, including those from the Intergovernmental Panel on Climate Change, had proved to be under-estimates of how fast and far the effects of global warming might move. − Climate News Network

New water for old as glaciers vanish

Voids left as glaciers vanish could be used to store spring snowmelt and rainfall to save the valleys below from summer droughts.

LONDON, 4 December, 2019 – Building dams in high mountains to store water as glaciers vanish could produce much-needed hydropower as well as saving people in the valleys below from summer droughts.

Following an earlier study of their own crisis of retreating glaciers in the Alps, Swiss glaciologists have carried out a worldwide study of 185,000 retreating rivers of ice to assess whether the empty valleys they leave behind could usefully be turned into holding dams.

The issue is urgent, because even with an average climate change scenario about three-quarters of the storage potential of these valleys could become ice-free by 2050 – and all of them by the end of the century.

The retreating ice – apart from spelling the end for some magnificent natural monuments – will dramatically affect the water cycle, leaving large river systems with seriously low flows, and some perhaps drying up altogether in the summer. This would have serious consequences for hydro-electricity production, agriculture and even drinking water for cities downstream.

Although water shortage is a potential problem in many high mountain regions, it is already affecting cities like Peru’s capital, Lima, which lies below the Andes. It also has the potential to cause serious problems in India, Pakistan and China, all of them reliant on summer run-off from the Himalayas.

“This theoretical total potential corresponds to about one third of current hydropower production worldwide. But, in reality, only part of it would be realisable”

The idea of the dams would be to capture the water from winter rainfall and spring snowmelt and retain it for gradual release during the summer – so, at least partly, replicating the current summer glacier melt.

ETH Zurich (the Swiss Federal Institute of Technology) and the Swiss Federal Institute for Forest, Snow and Landscape Research report, in a study published in the journal Nature, that the scheme could be viable in many countries.

The team calculated that theoretically the storage potential of these glacier valleys was 875 cubic kilometres of water, providing enormous hydropower potential.

Daniel Farinotti, professor of glaciology at ETH Zurich, who led the team, said: “This theoretical total potential corresponds to about one third of current hydropower production worldwide. But in reality, only part of it would be realisable.”

Since it was neither realistic nor desirable to build a dam in each of the thousands of the valleys vacated by glaciers, the researchers carried out a suitability assessment for all sites.

Significant addition

They identified around 40% of the theoretical total as “potentially” suitable, equalling a storage volume of 355 cubic km and a hydropower potential of 533 TWh per year. The latter corresponds to around 13% of current global hydropower production, or nine times Switzerland’s annual electricity demand.

“Even this potentially suitable storage volume would be sufficient to store about half of the annual runoff from the studied glacierised basins,” Professor Farinotti said.

The results show that basins which have lost their glaciers could contribute significantly to energy supply and water storage in a number of countries, particularly in the high mountain countries of Asia.

Among those with the largest potentials are Tajikistan, where the calculated hydropower potential could account for up to 80% of current electricity consumption, Chile (40%) and Pakistan (35%).

In Canada, Iceland, Bolivia and Norway, the potential equals 10–25% of their current electricity consumption. For Switzerland, the study shows a potential of 10%. – Climate News Network

Voids left as glaciers vanish could be used to store spring snowmelt and rainfall to save the valleys below from summer droughts.

LONDON, 4 December, 2019 – Building dams in high mountains to store water as glaciers vanish could produce much-needed hydropower as well as saving people in the valleys below from summer droughts.

Following an earlier study of their own crisis of retreating glaciers in the Alps, Swiss glaciologists have carried out a worldwide study of 185,000 retreating rivers of ice to assess whether the empty valleys they leave behind could usefully be turned into holding dams.

The issue is urgent, because even with an average climate change scenario about three-quarters of the storage potential of these valleys could become ice-free by 2050 – and all of them by the end of the century.

The retreating ice – apart from spelling the end for some magnificent natural monuments – will dramatically affect the water cycle, leaving large river systems with seriously low flows, and some perhaps drying up altogether in the summer. This would have serious consequences for hydro-electricity production, agriculture and even drinking water for cities downstream.

Although water shortage is a potential problem in many high mountain regions, it is already affecting cities like Peru’s capital, Lima, which lies below the Andes. It also has the potential to cause serious problems in India, Pakistan and China, all of them reliant on summer run-off from the Himalayas.

“This theoretical total potential corresponds to about one third of current hydropower production worldwide. But, in reality, only part of it would be realisable”

The idea of the dams would be to capture the water from winter rainfall and spring snowmelt and retain it for gradual release during the summer – so, at least partly, replicating the current summer glacier melt.

ETH Zurich (the Swiss Federal Institute of Technology) and the Swiss Federal Institute for Forest, Snow and Landscape Research report, in a study published in the journal Nature, that the scheme could be viable in many countries.

The team calculated that theoretically the storage potential of these glacier valleys was 875 cubic kilometres of water, providing enormous hydropower potential.

Daniel Farinotti, professor of glaciology at ETH Zurich, who led the team, said: “This theoretical total potential corresponds to about one third of current hydropower production worldwide. But in reality, only part of it would be realisable.”

Since it was neither realistic nor desirable to build a dam in each of the thousands of the valleys vacated by glaciers, the researchers carried out a suitability assessment for all sites.

Significant addition

They identified around 40% of the theoretical total as “potentially” suitable, equalling a storage volume of 355 cubic km and a hydropower potential of 533 TWh per year. The latter corresponds to around 13% of current global hydropower production, or nine times Switzerland’s annual electricity demand.

“Even this potentially suitable storage volume would be sufficient to store about half of the annual runoff from the studied glacierised basins,” Professor Farinotti said.

The results show that basins which have lost their glaciers could contribute significantly to energy supply and water storage in a number of countries, particularly in the high mountain countries of Asia.

Among those with the largest potentials are Tajikistan, where the calculated hydropower potential could account for up to 80% of current electricity consumption, Chile (40%) and Pakistan (35%).

In Canada, Iceland, Bolivia and Norway, the potential equals 10–25% of their current electricity consumption. For Switzerland, the study shows a potential of 10%. – Climate News Network

60-year drought ended ancient Assyrian empire

It took only a 60-year drought to lay low one of the first superpowers. It crumbled when harvests withered over two millennia ago.

LONDON, 25 November, 2019 − One of the great ancient empires, the neo-Assyrian world of what is now northern Iraq, flourished in years of plentiful rain, but buckled and collapsed when beset by a 60-year drought.

The biblical city of Nineveh fell in 612 BC, weakened by climate change, never to be occupied again. Chroniclers blamed political instability, the might of Babylon, and the invasions of Medes and Persians.

But climate scientists who have reconstructed the evidence of annual weather records have set the record straight: like the rings of a tree or the sediments in a lake, the isotope records in stalagmites in the floor of the Kuna Ba cave tell a story of a mega-drought that underlay the collapse of one of ancient history’s earliest superpowers.

Stalagmites or speleothems are built up by the steady drip of water through rock and onto the floor of a cave. The scientists report in the journal Science Advances that they used carbon and oxygen isotopes in the layers of stone to reconstruct the climate throughout a 3800-year sequence of rainfall patterns.

The measures of uranium and thorium trapped in the same speleothems provided precise dates for the entire sequence, and these could then be checked against surviving records from an empire that at its height, under King Sennacherib, extended into parts of what are now Turkey, Iran, Syria, Jordan, Lebanon, Israel and Egypt.

“These societies experienced climatic changes that were of such magnitude they could not simply adapt to them”

“We now know that the Assyrian droughts started decades earlier than we had previously thought, and also that the period prior to the onset of drought was one of the wettest in the entire roughly 3800-year sequence.

“It changes some of the other hypotheses we have made”, said Adam Schneider, of the University of Colorado at Boulder, who first proposed a climate link to imperial collapse in 2014.

“For example: King Sennacherib, who ruled from 705 to 681 BC, was well-known for building massive canals and other structures. In our earlier work on the question of drought in ancient Assyria, I and my colleague Dr. Selim Adali had initially viewed him as a short-sighted ruler who had pursued short-term political goals at the expense of long-term drought resilience, and set in motion a catastrophic chain of events as a result.

“But with this new data, we now think that Sennacherib probably was already experiencing drought when he was king, and in fact he may well have been trying to do something about the environmental calamity during that time.”

And a co-author, Harvey Weiss of Yale University, said : “Now we have a historical and environmental dynamic between north and south and between rain-fed agriculture and irrigation-fed agriculture through which we can understand the historical process of how the Babylonians were able to defeat the Assyrians.”

New theory

“This fits into a historical pattern that is not only structured through time and place, but a space and time that is filled with environmental change,” said Professor Weiss. “These societies experienced climatic changes that were of such magnitude they could not simply adapt to them.”

The climate change theory of history is relatively new, but has already been used to provide new explanations for the collapse of the Bronze Age empire in the Mediterranean 3,000 years ago, the downfall of the Ptolemaic dynasty in Egypt, the rise of Genghis Khan’s nomadic hordes  and the fall of the Mayan civilisation in the Americas.

There have been arguments that contemporary conflict can be matched to climate stress in many parts of the modern world.

“The French Revolution is one example. In the two years prior to the French Revolution poor weather led to a series of bad harvests, which alongside other factors helped cause the price of bread to skyrocket, especially in Paris,” said Professor Schneider.

“The question is not ‘Did climate have an impact?’ It’s ‘How, why and how important was climate alongside the other factors?’” − Climate News Network

It took only a 60-year drought to lay low one of the first superpowers. It crumbled when harvests withered over two millennia ago.

LONDON, 25 November, 2019 − One of the great ancient empires, the neo-Assyrian world of what is now northern Iraq, flourished in years of plentiful rain, but buckled and collapsed when beset by a 60-year drought.

The biblical city of Nineveh fell in 612 BC, weakened by climate change, never to be occupied again. Chroniclers blamed political instability, the might of Babylon, and the invasions of Medes and Persians.

But climate scientists who have reconstructed the evidence of annual weather records have set the record straight: like the rings of a tree or the sediments in a lake, the isotope records in stalagmites in the floor of the Kuna Ba cave tell a story of a mega-drought that underlay the collapse of one of ancient history’s earliest superpowers.

Stalagmites or speleothems are built up by the steady drip of water through rock and onto the floor of a cave. The scientists report in the journal Science Advances that they used carbon and oxygen isotopes in the layers of stone to reconstruct the climate throughout a 3800-year sequence of rainfall patterns.

The measures of uranium and thorium trapped in the same speleothems provided precise dates for the entire sequence, and these could then be checked against surviving records from an empire that at its height, under King Sennacherib, extended into parts of what are now Turkey, Iran, Syria, Jordan, Lebanon, Israel and Egypt.

“These societies experienced climatic changes that were of such magnitude they could not simply adapt to them”

“We now know that the Assyrian droughts started decades earlier than we had previously thought, and also that the period prior to the onset of drought was one of the wettest in the entire roughly 3800-year sequence.

“It changes some of the other hypotheses we have made”, said Adam Schneider, of the University of Colorado at Boulder, who first proposed a climate link to imperial collapse in 2014.

“For example: King Sennacherib, who ruled from 705 to 681 BC, was well-known for building massive canals and other structures. In our earlier work on the question of drought in ancient Assyria, I and my colleague Dr. Selim Adali had initially viewed him as a short-sighted ruler who had pursued short-term political goals at the expense of long-term drought resilience, and set in motion a catastrophic chain of events as a result.

“But with this new data, we now think that Sennacherib probably was already experiencing drought when he was king, and in fact he may well have been trying to do something about the environmental calamity during that time.”

And a co-author, Harvey Weiss of Yale University, said : “Now we have a historical and environmental dynamic between north and south and between rain-fed agriculture and irrigation-fed agriculture through which we can understand the historical process of how the Babylonians were able to defeat the Assyrians.”

New theory

“This fits into a historical pattern that is not only structured through time and place, but a space and time that is filled with environmental change,” said Professor Weiss. “These societies experienced climatic changes that were of such magnitude they could not simply adapt to them.”

The climate change theory of history is relatively new, but has already been used to provide new explanations for the collapse of the Bronze Age empire in the Mediterranean 3,000 years ago, the downfall of the Ptolemaic dynasty in Egypt, the rise of Genghis Khan’s nomadic hordes  and the fall of the Mayan civilisation in the Americas.

There have been arguments that contemporary conflict can be matched to climate stress in many parts of the modern world.

“The French Revolution is one example. In the two years prior to the French Revolution poor weather led to a series of bad harvests, which alongside other factors helped cause the price of bread to skyrocket, especially in Paris,” said Professor Schneider.

“The question is not ‘Did climate have an impact?’ It’s ‘How, why and how important was climate alongside the other factors?’” − Climate News Network

Greenhouse gases drive Australia’s bushfires

Australia’s bushfires are feeding on heat from the climate change happening in the tropics, but its government doesn’t want to know.

NEW SOUTH WALES, 14 November, 2019 − Australia has earned a formidable reputation for being the driest and most agriculturally disappointing continent on Earth. Droughts and floods have followed each other like day and night, spawning a laconic and resilient breed of agriculturalists known for taking climatic adversity and variability in their stride.

Everyone in the industry believes both good and bad times are cyclical, each replacing the other. The continent is surrounded by three oceans which, depending on their temperature fluxes, deliver or deny precious rainfall, as moisture-bearing ocean winds blow either toward the continent or away.

A knowledge of the state of each ocean can help farmers to understand how long it will be before the situation changes. Preparation for the next drought in good times is a no-brainer and is supported with Government policy. Water supply augmentation systems, fodder storage and stockpiling money are modern tricks used by graziers to abate the ravages of drought.

That’s been the traditional pattern. This year, though, after three consecutive failed springs in eastern Australia, there’s a level of despair which is taking an enormous toll on families, businesses and ecosystems. Farming communities are suffering mental anguish as they run out of options.

We haven’t seen the usual cyclical return to wetter seasons. No-one has ever seen the likes of this drought and no-one knows when it will end. We are out of tricks, out of water and out of feed.

Livestock breeding herds  and flocks that have taken generations to build are now depleted because the only option is to send them to slaughter. It’s unclear anyway whether there’ll be sufficient fodder-grade grain to keep them alive.

Breadbasket on fire

Modern cropping systems are designed to store soil moisture until the next crop can be planted. But in the bread basket of the nation, soil moisture is now at record lows, and severe bush fires ravage the landscape.

As I write this in the second week of November, we’re in the third day of gale-force winds, high temperatures and low humidity. The sky is full of dust, smoke and fire-fighting aircraft, when we should be planning what to do with excess stock feed.

Yesterday the government announced further assistance to farmers, in the billions. But the problem is that the federal government will not acknowledge there is a climate problem at all, let alone a catastrophe.

Deputy prime minister Michael McCormack aroused anger when he dismissed the possibility of climate change causing the crisis as the ravings of “pure, enlightened and woke capital city greenies” who were ignoring the needs of rural Australians. “We’ve had fires in Australia since time began”, he said.

Our understanding of the climatic drivers of this drought has been severely challenged. The Pacific Ocean is in a neutral phase, so ENSO is not a major issue. The Southern Ocean is in a negative mode, which should bring rain-bearing westerlies at least to southern Australia. But the Indian Ocean is in a phase which prevents tropical moisture inflow.

“The only way the climate models can simulate the depleted rainfall observations is to include the effects of greenhouse gases”

None of these by itself is enough to produce a drought as long and intense as this. In some places it is in its eighth year, and mostly at least the third. On our farm less than half of the annual rainfall of the previous worst year so far has been recorded. Apart from an intense La Niña in 2010-2011 there have been no significantly wet or average years this century.

In 2010 a report was released by a government agency, the Centre for Australian Weather and Climate Research, which showed conclusively that there has been a serious and persistent decline in rainfall in southwestern and more recently southeastern Australia. It is clearly visible, it is anthropogenic in nature, and its mechanism can be easily understood by non-scientists. The Australian Bureau of Meteorology published an update on this year’s drought in September.

Superimposed on the oceans’ tableau is a natural phenomenon known as the Sub-Tropical Ridge (STR). This is a belt of high atmospheric pressure which encircles the planet at about 35 degrees of latitude in both hemispheres, where many of the world’s deserts occur. This high pressure is caused by the descent of cool dry air at these latitudes.

This air originated in the tropics, rose, rained out and then descended, depleted of moisture. Meteorologists call this cycle the Hadley Circulation.

The trouble is that the dry high pressure cells are becoming more frequent and more intense because of growing heating in the sub-tropics, which are increasing in aridity.

Heat blocks rains

Until now, though, it was happening slowly enough for no-one to notice. However, recent analysis can now detect the signature as far back as the World War Two drought.

The STR is like a string of pearls under high pressure, with the gaps allowing rain-bearing systems to penetrate from either the tropics or the poles. But now the extra heat caused by climate change in the tropics is making the highs more frequent and more intense.

It is now a regular feature of Australian weather that rain-bearing fronts are pushed to the south and rarely penetrate the persistent highs. Similar changes have been seen in the northern hemisphere in southern Europe and California.

There is a direct linear relationship between these changes and the level of carbon dioxide in the atmosphere. The only way the climate models can simulate the depleted rainfall observations is to include the effects of greenhouse gases.

This should have been front-page news at least in the agricultural press, but instead the news is about government handouts to needy farmers.

Worse in store

So it looks as if the plight of Australian agriculture is set to worsen because of the tropical oceanic heating. The strengthening STR is not an oceanic phenomenon, but an atmospheric one, so its effects are not as apparent to the casual observer. Nevertheless, it seems to be putting the already nasty changes of the oceans on steroids.

Somehow we need to persuade the government that as well as providing welfare, and mitigation strategies, we have to stop venting novel carbon dioxide and avoid exposing Australian agriculture to the ravages of an angry atmosphere.

Yet there are now two strong reasons why governments in Australia will not acknowledge that the drought is attributable to climate change. Firstly, at the last election, there was an enormous voter backlash against proponents of the closure of coal mining.

Secondly, there is political mileage to be grafted out of massive welfare payments to the agricultural community. There is no doubt that there is enormous hardship in the sector, but you need to wonder whether they can see a connection between budgetary pain and carbon policy, or whether any government has sought briefing on the matter.

Clearly courage and leadership matching that required in warfare is needed to address this dreadful situation. Instead we have cowardice and schizophrenia. − Climate News Network

* * * * *

Andrew Burgess is a sheep farmer in New South Wales whose family has raised animals in the same area for more than a century. He has now sold his farm because he finds the drought has made his work and survival there impossible.

Australia’s bushfires are feeding on heat from the climate change happening in the tropics, but its government doesn’t want to know.

NEW SOUTH WALES, 14 November, 2019 − Australia has earned a formidable reputation for being the driest and most agriculturally disappointing continent on Earth. Droughts and floods have followed each other like day and night, spawning a laconic and resilient breed of agriculturalists known for taking climatic adversity and variability in their stride.

Everyone in the industry believes both good and bad times are cyclical, each replacing the other. The continent is surrounded by three oceans which, depending on their temperature fluxes, deliver or deny precious rainfall, as moisture-bearing ocean winds blow either toward the continent or away.

A knowledge of the state of each ocean can help farmers to understand how long it will be before the situation changes. Preparation for the next drought in good times is a no-brainer and is supported with Government policy. Water supply augmentation systems, fodder storage and stockpiling money are modern tricks used by graziers to abate the ravages of drought.

That’s been the traditional pattern. This year, though, after three consecutive failed springs in eastern Australia, there’s a level of despair which is taking an enormous toll on families, businesses and ecosystems. Farming communities are suffering mental anguish as they run out of options.

We haven’t seen the usual cyclical return to wetter seasons. No-one has ever seen the likes of this drought and no-one knows when it will end. We are out of tricks, out of water and out of feed.

Livestock breeding herds  and flocks that have taken generations to build are now depleted because the only option is to send them to slaughter. It’s unclear anyway whether there’ll be sufficient fodder-grade grain to keep them alive.

Breadbasket on fire

Modern cropping systems are designed to store soil moisture until the next crop can be planted. But in the bread basket of the nation, soil moisture is now at record lows, and severe bush fires ravage the landscape.

As I write this in the second week of November, we’re in the third day of gale-force winds, high temperatures and low humidity. The sky is full of dust, smoke and fire-fighting aircraft, when we should be planning what to do with excess stock feed.

Yesterday the government announced further assistance to farmers, in the billions. But the problem is that the federal government will not acknowledge there is a climate problem at all, let alone a catastrophe.

Deputy prime minister Michael McCormack aroused anger when he dismissed the possibility of climate change causing the crisis as the ravings of “pure, enlightened and woke capital city greenies” who were ignoring the needs of rural Australians. “We’ve had fires in Australia since time began”, he said.

Our understanding of the climatic drivers of this drought has been severely challenged. The Pacific Ocean is in a neutral phase, so ENSO is not a major issue. The Southern Ocean is in a negative mode, which should bring rain-bearing westerlies at least to southern Australia. But the Indian Ocean is in a phase which prevents tropical moisture inflow.

“The only way the climate models can simulate the depleted rainfall observations is to include the effects of greenhouse gases”

None of these by itself is enough to produce a drought as long and intense as this. In some places it is in its eighth year, and mostly at least the third. On our farm less than half of the annual rainfall of the previous worst year so far has been recorded. Apart from an intense La Niña in 2010-2011 there have been no significantly wet or average years this century.

In 2010 a report was released by a government agency, the Centre for Australian Weather and Climate Research, which showed conclusively that there has been a serious and persistent decline in rainfall in southwestern and more recently southeastern Australia. It is clearly visible, it is anthropogenic in nature, and its mechanism can be easily understood by non-scientists. The Australian Bureau of Meteorology published an update on this year’s drought in September.

Superimposed on the oceans’ tableau is a natural phenomenon known as the Sub-Tropical Ridge (STR). This is a belt of high atmospheric pressure which encircles the planet at about 35 degrees of latitude in both hemispheres, where many of the world’s deserts occur. This high pressure is caused by the descent of cool dry air at these latitudes.

This air originated in the tropics, rose, rained out and then descended, depleted of moisture. Meteorologists call this cycle the Hadley Circulation.

The trouble is that the dry high pressure cells are becoming more frequent and more intense because of growing heating in the sub-tropics, which are increasing in aridity.

Heat blocks rains

Until now, though, it was happening slowly enough for no-one to notice. However, recent analysis can now detect the signature as far back as the World War Two drought.

The STR is like a string of pearls under high pressure, with the gaps allowing rain-bearing systems to penetrate from either the tropics or the poles. But now the extra heat caused by climate change in the tropics is making the highs more frequent and more intense.

It is now a regular feature of Australian weather that rain-bearing fronts are pushed to the south and rarely penetrate the persistent highs. Similar changes have been seen in the northern hemisphere in southern Europe and California.

There is a direct linear relationship between these changes and the level of carbon dioxide in the atmosphere. The only way the climate models can simulate the depleted rainfall observations is to include the effects of greenhouse gases.

This should have been front-page news at least in the agricultural press, but instead the news is about government handouts to needy farmers.

Worse in store

So it looks as if the plight of Australian agriculture is set to worsen because of the tropical oceanic heating. The strengthening STR is not an oceanic phenomenon, but an atmospheric one, so its effects are not as apparent to the casual observer. Nevertheless, it seems to be putting the already nasty changes of the oceans on steroids.

Somehow we need to persuade the government that as well as providing welfare, and mitigation strategies, we have to stop venting novel carbon dioxide and avoid exposing Australian agriculture to the ravages of an angry atmosphere.

Yet there are now two strong reasons why governments in Australia will not acknowledge that the drought is attributable to climate change. Firstly, at the last election, there was an enormous voter backlash against proponents of the closure of coal mining.

Secondly, there is political mileage to be grafted out of massive welfare payments to the agricultural community. There is no doubt that there is enormous hardship in the sector, but you need to wonder whether they can see a connection between budgetary pain and carbon policy, or whether any government has sought briefing on the matter.

Clearly courage and leadership matching that required in warfare is needed to address this dreadful situation. Instead we have cowardice and schizophrenia. − Climate News Network

* * * * *

Andrew Burgess is a sheep farmer in New South Wales whose family has raised animals in the same area for more than a century. He has now sold his farm because he finds the drought has made his work and survival there impossible.

Water stress rises as more wells run dry

Soon, communities and even nations could be drawing water faster than the skies can replenish it. As the wells run dry, so will the rivers.

LONDON, 9 October, 2019 − Within three decades, almost 80% of the lands that depend on groundwater will start to reach their natural irrigation limits as the wells run dry.

In a world of increasing extremes of drought and rainfall, driven by rising global temperatures and potentially catastrophic climate change, the water will start to run out.

It is happening already: in 20% of those water catchments in which farmers and cities rely on pumped groundwater, the flow of streams and rivers has fallen and the surface flow has dwindled, changed direction or stopped altogether.

“The effects can be seen already in the Midwest of the United States and in the Indus Valley project between Afghanistan and Pakistan,” said Inge de Graaf, a hydrologist at the University of Freiburg.

Groundwater – the billions of tonnes locked in the soils and bedrock, held in vast chalk and limestone aquifers and silently flowing through cracks in other sediments – is the terrestrial planet’s biggest single store of the liquid that sustains all life.

“If we continue to pump as much groundwater in the coming decades as we have done so far, a critical point will be reached for regions in southern and central Europe as well as in North African countries”

Groundwater supplies the inland streams and rivers, and the flow from tributaries is an indicator of the levels of water already in the ground.

For thousands of years, communities have drawn water from wells in the dry season and relied on wet season rainfall to replenish it. But as human numbers have grown, as agriculture has commandeered more and more of the land, and as cities have burgeoned, demand has in some places begun to outstrip supply. The fear is that rising average temperatures will intensify the problem.

Dr de Graaf and colleagues from the Netherlands and Canada report in the journal Nature that they used computer simulations to establish the likely pattern of withdrawal and flow. The news is not good.

“We estimate that, by 2050, environmental flow limits will be reached for approximately 42% to 79% of the watershed in which there is groundwater pumping worldwide, and this will generally occur before substantial losses in groundwater storage are experienced,” they write.

That drylands – home to billions of people – will experience water stress with rising temperatures is not news. Climate scientists have been issuing warnings for years.

Ground level drops

And demand for groundwater has increased with the growth of the population and the worldwide growth of the cities: some US cities are at risk of coastal flooding just because so much groundwater has been extracted that the ground itself has been lowered.

The important thing about the latest research is that it sets – albeit broadly – a timetable and a map of where the water stress is likely to be experienced first.

In a hotter world, plants and animals will demand more water. But in a hotter world, the probability of extremes of drought increases.

“If we continue to pump as much groundwater in the coming decades as we have done so far, a critical point will be reached also for regions in southern and central Europe – such as Portugal, Spain and Italy – as well as in North African countries,” Dr de Graaf warned.

“Climate change may even accelerate this process, as we expect less precipitation, which will further increase the extraction of groundwater and cause dry areas to dry out completely.” − Climate News Network

Soon, communities and even nations could be drawing water faster than the skies can replenish it. As the wells run dry, so will the rivers.

LONDON, 9 October, 2019 − Within three decades, almost 80% of the lands that depend on groundwater will start to reach their natural irrigation limits as the wells run dry.

In a world of increasing extremes of drought and rainfall, driven by rising global temperatures and potentially catastrophic climate change, the water will start to run out.

It is happening already: in 20% of those water catchments in which farmers and cities rely on pumped groundwater, the flow of streams and rivers has fallen and the surface flow has dwindled, changed direction or stopped altogether.

“The effects can be seen already in the Midwest of the United States and in the Indus Valley project between Afghanistan and Pakistan,” said Inge de Graaf, a hydrologist at the University of Freiburg.

Groundwater – the billions of tonnes locked in the soils and bedrock, held in vast chalk and limestone aquifers and silently flowing through cracks in other sediments – is the terrestrial planet’s biggest single store of the liquid that sustains all life.

“If we continue to pump as much groundwater in the coming decades as we have done so far, a critical point will be reached for regions in southern and central Europe as well as in North African countries”

Groundwater supplies the inland streams and rivers, and the flow from tributaries is an indicator of the levels of water already in the ground.

For thousands of years, communities have drawn water from wells in the dry season and relied on wet season rainfall to replenish it. But as human numbers have grown, as agriculture has commandeered more and more of the land, and as cities have burgeoned, demand has in some places begun to outstrip supply. The fear is that rising average temperatures will intensify the problem.

Dr de Graaf and colleagues from the Netherlands and Canada report in the journal Nature that they used computer simulations to establish the likely pattern of withdrawal and flow. The news is not good.

“We estimate that, by 2050, environmental flow limits will be reached for approximately 42% to 79% of the watershed in which there is groundwater pumping worldwide, and this will generally occur before substantial losses in groundwater storage are experienced,” they write.

That drylands – home to billions of people – will experience water stress with rising temperatures is not news. Climate scientists have been issuing warnings for years.

Ground level drops

And demand for groundwater has increased with the growth of the population and the worldwide growth of the cities: some US cities are at risk of coastal flooding just because so much groundwater has been extracted that the ground itself has been lowered.

The important thing about the latest research is that it sets – albeit broadly – a timetable and a map of where the water stress is likely to be experienced first.

In a hotter world, plants and animals will demand more water. But in a hotter world, the probability of extremes of drought increases.

“If we continue to pump as much groundwater in the coming decades as we have done so far, a critical point will be reached also for regions in southern and central Europe – such as Portugal, Spain and Italy – as well as in North African countries,” Dr de Graaf warned.

“Climate change may even accelerate this process, as we expect less precipitation, which will further increase the extraction of groundwater and cause dry areas to dry out completely.” − Climate News Network

Drought may hit half world’s wheat at once

Wheat yields could be hit by severe drought across half the world at once, driving up prices and making problems for global markets.

LONDON, 2 October, 2019 − The planet’s daily bread could be at risk as the global thermometer creeps up and climates begin to change. New research has warned that almost two thirds of the world’s wheat-growing areas could face “severe, prolonged, and near-simultaneous droughts” by the century’s end.

Right now, 15% of the world’s wheat producing regions are at risk of severe water scarcity at the same time. Even if the 195 nations that agreed in Paris to stop global average temperatures from rising beyond 1.5°C by 2100 keep that promise, the chance of simultaneous water stress across continents would still double between 2030 and 2070.

But if nations fail to mitigate the climate change and extremes of heat and rainfall that would inevitably follow runaway global heating, then the chances of devastating failure of wheat harvests in both Europe and North America, or both Europe and Australia, or Russia, Ukraine and Kazakhstan, begin to soar.

Wheat provides one-fifth of all the calories for humankind. It is the world’s largest rain-fed crop and the global wheat trade matches the traffic in rice and in maize combined. Ten regions account for 54% of the planet’s wheat fields, and 57% of the world’s wheat.

“The results indicate a severely heightened risk of high-impact extreme events under the future climate”

Scientists from Europe, the US and China report in the journal Science Advances that they worked with computer simulations to model the future global weather for water scarcity with changes in temperature for the next eight decades.

Wheat is a successful crop partly because its water needs are relatively low, but it can’t flourish without reliable rainfall before and during growth. And the new simulations confirm earlier fears: that extremes of heat and devastating drought could happen in more than one continent at the same time.

When this happened in the 19th century, global famine followed. Forecasts already warn that with each 1°C rise in temperature, global wheat yield will fall by between 4% and 6.5%. Researchers have repeatedly warned that extremes of heat can slash yields and limit the vital nutrients in cereal harvests. Other teams have found that climate change may already be making this happen.

Worse could follow as one heat wave is pursued promptly by another. And all this could happen in a world in which, as population grows, demand for wheat could increase by at least 43%.

Continued checking

Scientists tend not to take the research of others for granted: they keep on checking. The latest simulation analysed 27 different climate models, each with three different scenarios.

The scientists looked at evidence from the near-past to find that between 1985 and 2007, the impact of drought on world wheat production was twice that between 1964 and 1984.

They included developing countries and low-income nations in eastern and southern Asia in their survey, because these are where half of the already hungry and under-nourished live, and where bread is an important part of people’s diet.

“The results indicate a severely heightened risk of high-impact extreme events under the future climate, which would likely affect all market players, ranging from direct influences on subsistence farmers to price-mediated changes in international markets”, they write. − Climate News Network

Wheat yields could be hit by severe drought across half the world at once, driving up prices and making problems for global markets.

LONDON, 2 October, 2019 − The planet’s daily bread could be at risk as the global thermometer creeps up and climates begin to change. New research has warned that almost two thirds of the world’s wheat-growing areas could face “severe, prolonged, and near-simultaneous droughts” by the century’s end.

Right now, 15% of the world’s wheat producing regions are at risk of severe water scarcity at the same time. Even if the 195 nations that agreed in Paris to stop global average temperatures from rising beyond 1.5°C by 2100 keep that promise, the chance of simultaneous water stress across continents would still double between 2030 and 2070.

But if nations fail to mitigate the climate change and extremes of heat and rainfall that would inevitably follow runaway global heating, then the chances of devastating failure of wheat harvests in both Europe and North America, or both Europe and Australia, or Russia, Ukraine and Kazakhstan, begin to soar.

Wheat provides one-fifth of all the calories for humankind. It is the world’s largest rain-fed crop and the global wheat trade matches the traffic in rice and in maize combined. Ten regions account for 54% of the planet’s wheat fields, and 57% of the world’s wheat.

“The results indicate a severely heightened risk of high-impact extreme events under the future climate”

Scientists from Europe, the US and China report in the journal Science Advances that they worked with computer simulations to model the future global weather for water scarcity with changes in temperature for the next eight decades.

Wheat is a successful crop partly because its water needs are relatively low, but it can’t flourish without reliable rainfall before and during growth. And the new simulations confirm earlier fears: that extremes of heat and devastating drought could happen in more than one continent at the same time.

When this happened in the 19th century, global famine followed. Forecasts already warn that with each 1°C rise in temperature, global wheat yield will fall by between 4% and 6.5%. Researchers have repeatedly warned that extremes of heat can slash yields and limit the vital nutrients in cereal harvests. Other teams have found that climate change may already be making this happen.

Worse could follow as one heat wave is pursued promptly by another. And all this could happen in a world in which, as population grows, demand for wheat could increase by at least 43%.

Continued checking

Scientists tend not to take the research of others for granted: they keep on checking. The latest simulation analysed 27 different climate models, each with three different scenarios.

The scientists looked at evidence from the near-past to find that between 1985 and 2007, the impact of drought on world wheat production was twice that between 1964 and 1984.

They included developing countries and low-income nations in eastern and southern Asia in their survey, because these are where half of the already hungry and under-nourished live, and where bread is an important part of people’s diet.

“The results indicate a severely heightened risk of high-impact extreme events under the future climate, which would likely affect all market players, ranging from direct influences on subsistence farmers to price-mediated changes in international markets”, they write. − Climate News Network

Starvation may force nations to war

Unless nations act now to halt the spread of deserts, they may face wars over food shortages and starvation by mid-century, the UN says.

DELHI, 26 September, 2019 − A stark warning that the exposure of more and more people to water scarcity, hunger and outright starvation may lead to the “failure of fragile states and regional conflicts” has been given by the United Nations as it attempts to galvanise governments into halting the spread of deserts before more cropland is lost.

The climate summit in New York was presented with a plan to try to halt the annual loss of 12 million hectares (30mn acres) of productive land caused by the nations which are parties to the UN’s Convention to Combat Desertification (UNCCD), which recently ended a high-level meeting here.

The plan was the list of actions nations agreed at the meeting of more than 190 countries to attempt to reverse the spread of land degradation that the UN estimates will displace 135 million people by 2045. The battle to halt the spread of deserts is seen by the UN as an integral part of the international effort to halt climate change.

How successful the new plans will be remains to be seen, as although  the Convention, like the Climate Change Convention, has been in existence since the last century, the problems continue to get worse. However, all the countries involved now have national plans to halt land degradation and restore croplands and forests.

One of the key new promises made at the Delhi meeting, which ended on 13 September, was to grant land tenure to groups to give them an incentive to protect soils and the ability of the land to grow crops.

“Land restoration is the cheapest solution to climate change and biodiversity loss”

Delegates also agreed to improve the rights of women, promote land restoration and reduce land-related carbon emissions, both from poor soil management and the destruction of trees. New ways of financing these schemes from government and private sources were proposed.

The scale of the problem is enormous. Close to a quarter of global land is almost unusable, and by the middle of the century humans will need to produce twice as much grain as they do today to keep up with global population growth, the UNCCD says.

At the closing session Ibrahim Thiaw, executive secretary of the UNCCD, said: “Land restoration is the cheapest solution to climate change and biodiversity loss; land restoration makes business sense if we have regulations and incentives to reward investment.”

In addition, he said, preparing for the increasing number of droughts and coping with them are critical in the face of climate change. He emphasised the need to involve young people and women and to secure land rights.

However, despite the adoption of the New Delhi Declaration, in which ministers and delegates expressed support for new initiatives or coalitions aiming to improve human health and well-being and the health of ecosystems, and to advance peace and security, there were dissenting voices at the conference.

Dilution and omissions

The Centre for Science and Environment (CSE) said in a statement: “The New Delhi Declaration has diluted the role of international funding bodies in combating desertification. It has also sidestepped the contentious issue of tenure rights to land.”

The CSE said the statement had removed any mention of the Green Climate Fund, the Global Environment Facility and the Adaptation Fund  from the Declaration and there were no mentions of specific measures that could be used for adaptation nor, in fact, the word “adaptation” itself. Countries were left to develop their own plans.

Local politics also plays an important part in creating the problem. For example, across South Asia severe drought areas are used for water-guzzling crops such as sugarcane, or for very large monoculture plantations for palm oil or rubber.

Some speakers felt it was going to be an uphill struggle for poorer countries to get funding for restoring degraded land.

Early warning systems, climate-resilient infrastructure, improved dry land agriculture, mangrove protection and investments in making water resources more resilient were all vital. Adapting to land degradation and climate change was in everyone’s strong economic self-interest, Thiaw said. − Climate News Network

Unless nations act now to halt the spread of deserts, they may face wars over food shortages and starvation by mid-century, the UN says.

DELHI, 26 September, 2019 − A stark warning that the exposure of more and more people to water scarcity, hunger and outright starvation may lead to the “failure of fragile states and regional conflicts” has been given by the United Nations as it attempts to galvanise governments into halting the spread of deserts before more cropland is lost.

The climate summit in New York was presented with a plan to try to halt the annual loss of 12 million hectares (30mn acres) of productive land caused by the nations which are parties to the UN’s Convention to Combat Desertification (UNCCD), which recently ended a high-level meeting here.

The plan was the list of actions nations agreed at the meeting of more than 190 countries to attempt to reverse the spread of land degradation that the UN estimates will displace 135 million people by 2045. The battle to halt the spread of deserts is seen by the UN as an integral part of the international effort to halt climate change.

How successful the new plans will be remains to be seen, as although  the Convention, like the Climate Change Convention, has been in existence since the last century, the problems continue to get worse. However, all the countries involved now have national plans to halt land degradation and restore croplands and forests.

One of the key new promises made at the Delhi meeting, which ended on 13 September, was to grant land tenure to groups to give them an incentive to protect soils and the ability of the land to grow crops.

“Land restoration is the cheapest solution to climate change and biodiversity loss”

Delegates also agreed to improve the rights of women, promote land restoration and reduce land-related carbon emissions, both from poor soil management and the destruction of trees. New ways of financing these schemes from government and private sources were proposed.

The scale of the problem is enormous. Close to a quarter of global land is almost unusable, and by the middle of the century humans will need to produce twice as much grain as they do today to keep up with global population growth, the UNCCD says.

At the closing session Ibrahim Thiaw, executive secretary of the UNCCD, said: “Land restoration is the cheapest solution to climate change and biodiversity loss; land restoration makes business sense if we have regulations and incentives to reward investment.”

In addition, he said, preparing for the increasing number of droughts and coping with them are critical in the face of climate change. He emphasised the need to involve young people and women and to secure land rights.

However, despite the adoption of the New Delhi Declaration, in which ministers and delegates expressed support for new initiatives or coalitions aiming to improve human health and well-being and the health of ecosystems, and to advance peace and security, there were dissenting voices at the conference.

Dilution and omissions

The Centre for Science and Environment (CSE) said in a statement: “The New Delhi Declaration has diluted the role of international funding bodies in combating desertification. It has also sidestepped the contentious issue of tenure rights to land.”

The CSE said the statement had removed any mention of the Green Climate Fund, the Global Environment Facility and the Adaptation Fund  from the Declaration and there were no mentions of specific measures that could be used for adaptation nor, in fact, the word “adaptation” itself. Countries were left to develop their own plans.

Local politics also plays an important part in creating the problem. For example, across South Asia severe drought areas are used for water-guzzling crops such as sugarcane, or for very large monoculture plantations for palm oil or rubber.

Some speakers felt it was going to be an uphill struggle for poorer countries to get funding for restoring degraded land.

Early warning systems, climate-resilient infrastructure, improved dry land agriculture, mangrove protection and investments in making water resources more resilient were all vital. Adapting to land degradation and climate change was in everyone’s strong economic self-interest, Thiaw said. − Climate News Network

Moderate forest damage raises local temperature

Trees cool the world. They also cool themselves. Even moderate forest damage makes local temperatures soar.

LONDON, 13 September, 2019 − Destruction of the Amazon rainforest is bad news for the planet. It isn’t good news for the people, plants and animals of the region either. And even moderate forest damage raises local temperatures faster than it can affect the average global temperature.

British researchers used comprehensive and systematic sets of satellite data to test the local temperatures of both surviving tropical rainforest in the Amazon basin, and of the surfaces cleared of canopy by fire, axe, drought and grazing.

They report that even if two-thirds of the tree cover survived, the local ground temperature increased. The more canopy that was lost, the more pronounced the effect.

Local thermometer readings went up by almost half a degree in the first 13 years of this century, compared with the original undisturbed forest. And in the dry season, over the areas most affected by severe deforestation, the average temperatures soared by 1.5°C compared with intact forest.

This figure of 1.5°C has almost iconic status. It represents what 195 nations in Paris in 2015 agreed should be the limit of global average warming by the end of the century.

“The Amazon wildfires have reminded us all of the important role that forests play in our global systems. But intact Amazon forests are also crucially important for Brazil’s local climate”

Forests – and in particular the tropical rainforests – are part of the global strategy to constrain global heating driven by ever-increasing levels of greenhouse gases in the atmosphere, themselves the product of fossil fuel use and the destruction of grasslands and forests.

In a process called evapotranspiration, great tracts of canopy draw cascades of water from the soil and release it into the atmosphere, to lower local temperatures and at the same time absorb atmospheric carbon dioxide.

But rainforests such as the Amazon are also at risk, directly from human assault and less directly from global heating as higher temperatures increase the hazard of longer droughts, which in turn intensifies the loss of canopy.

And political change in Brazil now means that the planet’s “green lungs” are more at risk than ever, as fires blaze over the region.

Jessica Baker from the University of Leeds and her co-author report in the journal Frontiers in Forests and Global Change that almost one million square kilometres – an area the size of Egypt – of the Amazon has already been cleared: this is nearly a fifth of the original forest.

Damage increases heat

The researchers combed through local studies, satellite observations made by day and night, and other research to grade the forest as intact or no longer intact, and then as moderately or severely affected, and then started comparing averaged data from the three years 2001-2003 with that of 2011-2013.

They found that even if 70% of the canopy survived, the damaged forest was significantly warmer than the nearest intact forest. Towards the end of the dry season of August and September, heavily disturbed forest regions warmed by as much as 1.5°C compared to intact canopy.

“The Amazon wildfires have reminded us all of the important role that forests play in our global systems,” Dr Baker said. “But it cannot be overlooked that intact Amazon forests are also crucially important for Brazil’s local climate.”

And her co-author Dominick Spracklen said: “Evapotranspiration can be thought of as the forest ‘sweating’; when the moisture emitted by the forests evaporates it cools the local climate. Deforestation reduces evapotranspiration, taking away this cooling function and causing local temperatures to rise.

“As temperatures rise this increases drought stress and makes forests more susceptible to burning.” − Climate News Network

Trees cool the world. They also cool themselves. Even moderate forest damage makes local temperatures soar.

LONDON, 13 September, 2019 − Destruction of the Amazon rainforest is bad news for the planet. It isn’t good news for the people, plants and animals of the region either. And even moderate forest damage raises local temperatures faster than it can affect the average global temperature.

British researchers used comprehensive and systematic sets of satellite data to test the local temperatures of both surviving tropical rainforest in the Amazon basin, and of the surfaces cleared of canopy by fire, axe, drought and grazing.

They report that even if two-thirds of the tree cover survived, the local ground temperature increased. The more canopy that was lost, the more pronounced the effect.

Local thermometer readings went up by almost half a degree in the first 13 years of this century, compared with the original undisturbed forest. And in the dry season, over the areas most affected by severe deforestation, the average temperatures soared by 1.5°C compared with intact forest.

This figure of 1.5°C has almost iconic status. It represents what 195 nations in Paris in 2015 agreed should be the limit of global average warming by the end of the century.

“The Amazon wildfires have reminded us all of the important role that forests play in our global systems. But intact Amazon forests are also crucially important for Brazil’s local climate”

Forests – and in particular the tropical rainforests – are part of the global strategy to constrain global heating driven by ever-increasing levels of greenhouse gases in the atmosphere, themselves the product of fossil fuel use and the destruction of grasslands and forests.

In a process called evapotranspiration, great tracts of canopy draw cascades of water from the soil and release it into the atmosphere, to lower local temperatures and at the same time absorb atmospheric carbon dioxide.

But rainforests such as the Amazon are also at risk, directly from human assault and less directly from global heating as higher temperatures increase the hazard of longer droughts, which in turn intensifies the loss of canopy.

And political change in Brazil now means that the planet’s “green lungs” are more at risk than ever, as fires blaze over the region.

Jessica Baker from the University of Leeds and her co-author report in the journal Frontiers in Forests and Global Change that almost one million square kilometres – an area the size of Egypt – of the Amazon has already been cleared: this is nearly a fifth of the original forest.

Damage increases heat

The researchers combed through local studies, satellite observations made by day and night, and other research to grade the forest as intact or no longer intact, and then as moderately or severely affected, and then started comparing averaged data from the three years 2001-2003 with that of 2011-2013.

They found that even if 70% of the canopy survived, the damaged forest was significantly warmer than the nearest intact forest. Towards the end of the dry season of August and September, heavily disturbed forest regions warmed by as much as 1.5°C compared to intact canopy.

“The Amazon wildfires have reminded us all of the important role that forests play in our global systems,” Dr Baker said. “But it cannot be overlooked that intact Amazon forests are also crucially important for Brazil’s local climate.”

And her co-author Dominick Spracklen said: “Evapotranspiration can be thought of as the forest ‘sweating’; when the moisture emitted by the forests evaporates it cools the local climate. Deforestation reduces evapotranspiration, taking away this cooling function and causing local temperatures to rise.

“As temperatures rise this increases drought stress and makes forests more susceptible to burning.” − Climate News Network

Sand and dust storms pose global threat

The United Nations plans to tame lethal sand and dust storms with a mixture of modern technology and traditional knowledge.

DELHI, 12 September, 2019 − The standard bearer of the United Nations’ effort to combat desert spread and the threat from sand and dust storms, meeting here, is determined to be remembered as not just a global talking shop, but a launchpad for action.

The UN Convention to Combat Desertification (UNCCD) has launched a coalition to energise the UN’s response to the problem.  One focus for the new body will be to develop the sand and dust storms (SDS) source base map to improve the monitoring of the storms.

Iran told the meeting that both traditional and modern knowledge on SDS hot spots could help to create a stronger knowledge base for regional initiatives. The coalition’s members include  the International Civil Aviation Organization and the World Meteorological Organization (WMO).

The WMO already has an established SDS warning advisory system (SDS-WAS) to research the problem and try to provide forecasts of dangerous storms. Countries are now being asked to explore ways of reducing man-made contributions to dust storms, for example by not denuding land of vegetation.

Climate change and extreme weather have made SDS a threat to more than 150 countries, causing economic damage and threatening health. The storms, once thought of as a local problem in desert or arid regions, are now recognised as a global hazard.

“There is a need for more accurate real-time observations of dust properties and for understanding dust triggering mechanisms, seasonal variabilities, and transport dynamics”

Huge quantities of sand and dust can be lifted into the air by high winds and distributed over hundreds of miles. The problem is worsening as droughts increase and land is degraded by deforestation and poor agricultural practices.

Dust is also intensifying climate change, for example by discolouring ice so that it melts faster, and human health is affected by increased asthma and the spread of diseases such as valley fever and meningitis.

Aviation suffers when storms close airports or cause damage when dust is sucked into engines. Roads are lost under sand and electricity supplies disrupted. Even fisheries are damaged by sand settling in the oceans and affecting plankton growth.

The storms can be severe. In 2018 more than 125 people died and 200 were injured by a high-velocity dust storm in northern India. Even in Europe large areas can be covered in orange sand and dust from the Sahara.

Hesham El-Askary, professor of earth systems science and remote sensing at Chapman University in California, said: “There is a need for more accurate real-time observations of dust properties and for understanding dust triggering mechanisms, seasonal variabilities, and transport dynamics to assist mitigation of windblown dust consequences in many applications. These include human health, weather, solar and wind energy systems, aviation, highway safety and urban development.”

Higher cyclone intensity

The Asia Pacific Disaster Report 2019, released in August, suggests that the impacts of climate change differ by sub-region: “Temperature increase is likely to cause a rise in the number and duration of heat waves and droughts . . . Climate change is also expected to increase cyclone intensity, with serious threats along the coastal areas of countries in south-east Asia.”

A complex sequence of climate and weather disasters such as drought, SDS, desertification and floods is on the rise in arid and semi-arid sub-regions of south-west and central Asia, the report said. And, as indicated clearly in the recent IPCC report on global warming of 1.5°C, the decrease in soil moisture will increase the frequency and intensity of sand and dust storms in south, south-west and central Asia.

A recent example was the powerful dust storm that swept over parts of Iran, Afghanistan and Pakistan in May 2018. There was also a toxic salt storm from the Aral Sea that hit northern Turkmenistan and western Uzbekistan.

The storms then moved through Iran, Afghanistan, Pakistan and north-west India and collided with the pre-monsoon weather, including thunderstorms and rain, affecting a wide area and causing the loss of hundreds of lives. − Climate News Network

* * * * *

Nivedita Khandekar is an independent journalist based in Delhi. She writes on environmental and developmental issues. Email: nivedita_him@rediffmail.com; Twitter: @nivedita_Him

The United Nations plans to tame lethal sand and dust storms with a mixture of modern technology and traditional knowledge.

DELHI, 12 September, 2019 − The standard bearer of the United Nations’ effort to combat desert spread and the threat from sand and dust storms, meeting here, is determined to be remembered as not just a global talking shop, but a launchpad for action.

The UN Convention to Combat Desertification (UNCCD) has launched a coalition to energise the UN’s response to the problem.  One focus for the new body will be to develop the sand and dust storms (SDS) source base map to improve the monitoring of the storms.

Iran told the meeting that both traditional and modern knowledge on SDS hot spots could help to create a stronger knowledge base for regional initiatives. The coalition’s members include  the International Civil Aviation Organization and the World Meteorological Organization (WMO).

The WMO already has an established SDS warning advisory system (SDS-WAS) to research the problem and try to provide forecasts of dangerous storms. Countries are now being asked to explore ways of reducing man-made contributions to dust storms, for example by not denuding land of vegetation.

Climate change and extreme weather have made SDS a threat to more than 150 countries, causing economic damage and threatening health. The storms, once thought of as a local problem in desert or arid regions, are now recognised as a global hazard.

“There is a need for more accurate real-time observations of dust properties and for understanding dust triggering mechanisms, seasonal variabilities, and transport dynamics”

Huge quantities of sand and dust can be lifted into the air by high winds and distributed over hundreds of miles. The problem is worsening as droughts increase and land is degraded by deforestation and poor agricultural practices.

Dust is also intensifying climate change, for example by discolouring ice so that it melts faster, and human health is affected by increased asthma and the spread of diseases such as valley fever and meningitis.

Aviation suffers when storms close airports or cause damage when dust is sucked into engines. Roads are lost under sand and electricity supplies disrupted. Even fisheries are damaged by sand settling in the oceans and affecting plankton growth.

The storms can be severe. In 2018 more than 125 people died and 200 were injured by a high-velocity dust storm in northern India. Even in Europe large areas can be covered in orange sand and dust from the Sahara.

Hesham El-Askary, professor of earth systems science and remote sensing at Chapman University in California, said: “There is a need for more accurate real-time observations of dust properties and for understanding dust triggering mechanisms, seasonal variabilities, and transport dynamics to assist mitigation of windblown dust consequences in many applications. These include human health, weather, solar and wind energy systems, aviation, highway safety and urban development.”

Higher cyclone intensity

The Asia Pacific Disaster Report 2019, released in August, suggests that the impacts of climate change differ by sub-region: “Temperature increase is likely to cause a rise in the number and duration of heat waves and droughts . . . Climate change is also expected to increase cyclone intensity, with serious threats along the coastal areas of countries in south-east Asia.”

A complex sequence of climate and weather disasters such as drought, SDS, desertification and floods is on the rise in arid and semi-arid sub-regions of south-west and central Asia, the report said. And, as indicated clearly in the recent IPCC report on global warming of 1.5°C, the decrease in soil moisture will increase the frequency and intensity of sand and dust storms in south, south-west and central Asia.

A recent example was the powerful dust storm that swept over parts of Iran, Afghanistan and Pakistan in May 2018. There was also a toxic salt storm from the Aral Sea that hit northern Turkmenistan and western Uzbekistan.

The storms then moved through Iran, Afghanistan, Pakistan and north-west India and collided with the pre-monsoon weather, including thunderstorms and rain, affecting a wide area and causing the loss of hundreds of lives. − Climate News Network

* * * * *

Nivedita Khandekar is an independent journalist based in Delhi. She writes on environmental and developmental issues. Email: nivedita_him@rediffmail.com; Twitter: @nivedita_Him