Tag Archives: Drought

New forests mean permanently lower river flows

Planting trees helps to combat the climate crisis by cutting greenhouse gases. But the price can be permanently lower river flows.

LONDON, 20 January, 2020 − New forests are an apparently promising way to tackle global heating: the trees absorb carbon dioxide, the main greenhouse gas from human activities. But there’s a snag, because permanently lower river flows can be an unintended consequence.

A study by scientists at the University of Cambridge, UK, has found that river flow is reduced in areas where forests have been planted − and, significantly, it does not recover over time. Rivers in some regions can disappear completely within 10 years.

This, the researchers say, highlights the need to consider the impact on regional water availability, as well as the wider climate benefit of tree-planting plans.

“Reforestation is an important part of tackling climate change, but we need to carefully consider the best places for it. In some places, changes to water availability will completely change the local cost-benefits of tree-planting programmes”, said Laura Bentley, a plant scientist in the University of Cambridge Conservation Research Institute, and first author of the report.

Age effect missed

Planting large areas of trees has been suggested as one of the best ways of reducing atmospheric carbon dioxide levels, because trees absorb and store the gas as they grow, although uncertainties about the strategy persist. Science has known for a long time that planting trees reduces the amount of water flowing into nearby rivers, but no-one had realised how this effect changes as forests age.

The Cambridge study looked at 43 sites across the world where forests have been established, and used river flow as a measure of water availability in the region. It found that within five years of planting trees, river flow had reduced by an average of 25%.

But 25 years after the trees were planted, rivers had gone down by an average of 40%, or in a few cases had dried up altogether. The biggest percentage reductions in water availability were in parts of Australia and South Africa.

“River flow does not recover after planting trees, even after many years, once disturbances in the catchment and the effects of climate are accounted for,” said Professor David Coomes, director of the Conservation Research Institute, who led the study.

“In some places, changes to water availability will completely change the local cost-benefits of tree-planting programmes”

Published in the journal Global Change Biology, the research showed that the type of land where trees are planted determines the impact they have on local water availability.

Trees planted on natural grassland where the soil is healthy decrease river flow significantly. But on land previously degraded by agriculture, establishing a forest helps to repair the soil so that it can hold more water, and therefore decreases nearby river flow by a smaller amount.

Strangely, the effect of trees on river flow is smaller in drier years than in wetter ones. When trees are drought-stressed they close the pores on their leaves to conserve water, and as a result take up less water from the soil. In wet weather, though, they use more water from the soil, and also catch the rainwater in their leaves.

“Climate change will affect water availability around the world,” said Bentley. “By studying how forestation affects water availability, we can work to minimise any local consequences for people and the environment.” − Climate News Network

Planting trees helps to combat the climate crisis by cutting greenhouse gases. But the price can be permanently lower river flows.

LONDON, 20 January, 2020 − New forests are an apparently promising way to tackle global heating: the trees absorb carbon dioxide, the main greenhouse gas from human activities. But there’s a snag, because permanently lower river flows can be an unintended consequence.

A study by scientists at the University of Cambridge, UK, has found that river flow is reduced in areas where forests have been planted − and, significantly, it does not recover over time. Rivers in some regions can disappear completely within 10 years.

This, the researchers say, highlights the need to consider the impact on regional water availability, as well as the wider climate benefit of tree-planting plans.

“Reforestation is an important part of tackling climate change, but we need to carefully consider the best places for it. In some places, changes to water availability will completely change the local cost-benefits of tree-planting programmes”, said Laura Bentley, a plant scientist in the University of Cambridge Conservation Research Institute, and first author of the report.

Age effect missed

Planting large areas of trees has been suggested as one of the best ways of reducing atmospheric carbon dioxide levels, because trees absorb and store the gas as they grow, although uncertainties about the strategy persist. Science has known for a long time that planting trees reduces the amount of water flowing into nearby rivers, but no-one had realised how this effect changes as forests age.

The Cambridge study looked at 43 sites across the world where forests have been established, and used river flow as a measure of water availability in the region. It found that within five years of planting trees, river flow had reduced by an average of 25%.

But 25 years after the trees were planted, rivers had gone down by an average of 40%, or in a few cases had dried up altogether. The biggest percentage reductions in water availability were in parts of Australia and South Africa.

“River flow does not recover after planting trees, even after many years, once disturbances in the catchment and the effects of climate are accounted for,” said Professor David Coomes, director of the Conservation Research Institute, who led the study.

“In some places, changes to water availability will completely change the local cost-benefits of tree-planting programmes”

Published in the journal Global Change Biology, the research showed that the type of land where trees are planted determines the impact they have on local water availability.

Trees planted on natural grassland where the soil is healthy decrease river flow significantly. But on land previously degraded by agriculture, establishing a forest helps to repair the soil so that it can hold more water, and therefore decreases nearby river flow by a smaller amount.

Strangely, the effect of trees on river flow is smaller in drier years than in wetter ones. When trees are drought-stressed they close the pores on their leaves to conserve water, and as a result take up less water from the soil. In wet weather, though, they use more water from the soil, and also catch the rainwater in their leaves.

“Climate change will affect water availability around the world,” said Bentley. “By studying how forestation affects water availability, we can work to minimise any local consequences for people and the environment.” − Climate News Network

Australia’s sunshine could spare its blazing forests

The hellish sight of Australia’s blazing forests threatens to become all too familiar. But the future doesn’t have to be like this.



LONDON, 16 January, 2020 − Australia burns, and recent studies show that the severity of the heat waves there has been exacerbated by climate change, fuelling this year’s extensive bush fires and torching the blazing forests. And yet Scott Morrison, Australia’s Prime Minister, has not faltered in his support for the fossil fuel industry.

To be fair, he is in a difficult situation. A significant part of the Australian economy is dependent on coal, and the economy would take a real hit if coal mining was shut down. On the other hand, it is clear that the coal industry is a major driver of climate change, the consequences of which his voters are suffering from. There is no easy way out. Morrison’s approval ratings have fallen from +2 to -12 during the past month.

So what can Mr Morrison do if he wants to reduce the impact that climate change will have on Australia’s forests? In my opinion, the answer is obvious. He should make good use of the other natural resource that his country has in abundance: sunshine. Sunshine means energy. For a big country like Australia, it means lots of energy.

Exporting solar-powered electricity directly to neighbouring countries is impractical and not very cost-effective − not least because, for Australia, there are very few such neighbouring countries. However, solar energy could be used to produce synthetic hydrocarbons and be stored and transported that way.

“Mr Morrison, are you prepared to take the initiative in making use of your vast reserves of solar energy to help make the aviation industry significantly greener?”

To take a practical example, there is no prospect in the foreseeable future of airliners being able to run directly on electric batteries charged by renewable sources – to cross the Atlantic, say, the batteries would simply be too heavy. In this respect, kerosene is a remarkable chemical, storing so much energy per gram of fuel. We cannot simply stop aircraft flying – the world’s economy depends on aviation.

Kerosene, as burnt by today’s aircraft, derives from fossil carbon, and it is our emissions of fossil carbon that are causing the climate to change and the Australian bush to burn. But it doesn’t have to be made from fossil carbon.

It can be made by sucking carbon dioxide out of the air and combining it with hydrogen, which has been made by separating it out from oxygen in common-or-garden water (a process known as hydrolysis).

Of course, this process requires energy, and it makes no sense to create synthetic kerosene using energy from fossil carbon. But it makes sense if the kerosene is made using solar energy.

Cost problem

Research has shown that producing synthetic kerosene in this way is possible. The problem of producing it at scale is one of cost. According to recent estimates, the cost of oil would have to exceed US$100 a barrel for synthetic kerosene to become viable.

This is the time for the countries of the world, especially those who have signed up to the 2015 Paris Agreement, to make commitments. A concrete proposal would be that past 2030, aircraft that land and take off at airports in these countries will, if the planes run on fossil kerosene, be taxed by an amount that would make it economically much more attractive for them to run on synthetic kerosene.

Of course, this won’t make sense unless synthetic kerosene is available in sufficient amounts. Herein lies Australia’s unique economic opportunity. As a politically stable country, we would not have to worry about supplies getting shut off by political instability, a concern for some other sunny parts of the world. Australia could easily become the go-to country for synthetic kerosene.

The developed countries of the world should take the lead in announcing a date when planes landing or taking off at their airports will be taxed extra if they burn fossil kerosene. Mr Morrison, if they do so, are you prepared to take the initiative in making use of your vast reserves of solar energy to help make the aviation industry significantly greener? Even if it is only to safeguard your own forests. − Climate News Network

* * * * * * *

Tim Palmer is a Royal Society Research Professor in Climate Physics at the University of Oxford, UK.

The hellish sight of Australia’s blazing forests threatens to become all too familiar. But the future doesn’t have to be like this.



LONDON, 16 January, 2020 − Australia burns, and recent studies show that the severity of the heat waves there has been exacerbated by climate change, fuelling this year’s extensive bush fires and torching the blazing forests. And yet Scott Morrison, Australia’s Prime Minister, has not faltered in his support for the fossil fuel industry.

To be fair, he is in a difficult situation. A significant part of the Australian economy is dependent on coal, and the economy would take a real hit if coal mining was shut down. On the other hand, it is clear that the coal industry is a major driver of climate change, the consequences of which his voters are suffering from. There is no easy way out. Morrison’s approval ratings have fallen from +2 to -12 during the past month.

So what can Mr Morrison do if he wants to reduce the impact that climate change will have on Australia’s forests? In my opinion, the answer is obvious. He should make good use of the other natural resource that his country has in abundance: sunshine. Sunshine means energy. For a big country like Australia, it means lots of energy.

Exporting solar-powered electricity directly to neighbouring countries is impractical and not very cost-effective − not least because, for Australia, there are very few such neighbouring countries. However, solar energy could be used to produce synthetic hydrocarbons and be stored and transported that way.

“Mr Morrison, are you prepared to take the initiative in making use of your vast reserves of solar energy to help make the aviation industry significantly greener?”

To take a practical example, there is no prospect in the foreseeable future of airliners being able to run directly on electric batteries charged by renewable sources – to cross the Atlantic, say, the batteries would simply be too heavy. In this respect, kerosene is a remarkable chemical, storing so much energy per gram of fuel. We cannot simply stop aircraft flying – the world’s economy depends on aviation.

Kerosene, as burnt by today’s aircraft, derives from fossil carbon, and it is our emissions of fossil carbon that are causing the climate to change and the Australian bush to burn. But it doesn’t have to be made from fossil carbon.

It can be made by sucking carbon dioxide out of the air and combining it with hydrogen, which has been made by separating it out from oxygen in common-or-garden water (a process known as hydrolysis).

Of course, this process requires energy, and it makes no sense to create synthetic kerosene using energy from fossil carbon. But it makes sense if the kerosene is made using solar energy.

Cost problem

Research has shown that producing synthetic kerosene in this way is possible. The problem of producing it at scale is one of cost. According to recent estimates, the cost of oil would have to exceed US$100 a barrel for synthetic kerosene to become viable.

This is the time for the countries of the world, especially those who have signed up to the 2015 Paris Agreement, to make commitments. A concrete proposal would be that past 2030, aircraft that land and take off at airports in these countries will, if the planes run on fossil kerosene, be taxed by an amount that would make it economically much more attractive for them to run on synthetic kerosene.

Of course, this won’t make sense unless synthetic kerosene is available in sufficient amounts. Herein lies Australia’s unique economic opportunity. As a politically stable country, we would not have to worry about supplies getting shut off by political instability, a concern for some other sunny parts of the world. Australia could easily become the go-to country for synthetic kerosene.

The developed countries of the world should take the lead in announcing a date when planes landing or taking off at their airports will be taxed extra if they burn fossil kerosene. Mr Morrison, if they do so, are you prepared to take the initiative in making use of your vast reserves of solar energy to help make the aviation industry significantly greener? Even if it is only to safeguard your own forests. − Climate News Network

* * * * * * *

Tim Palmer is a Royal Society Research Professor in Climate Physics at the University of Oxford, UK.

Can batteries help to limit bushfire horrors?

The Australian inferno has yet to reach its worst, but already minds are seeking ways to reduce the bushfire horrors. Could batteries help next time?

LONDON, 9 January, 2020 − With at least 27 human fatalities and a scarcely credible estimate by scientists that more than one billion animals have been killed nationwide by the unprecedented blazes  since September 2019, Australia’s bushfire horrors have stunned the world.

The climate crisis is contributing to the catastrophe, at least to its scale and intensity, whether or not it is its primary cause. And scientists revealed only this month that global heating is causing daily weather change.

But something else happened in Australia in 2019 which could point the way towards a fast route, not for Australia alone but globally, to renewable energy and a safer future.

In the state of South Australia the world’s biggest lithium-ion battery – 129MWh, able to power 30,000 homes for an hour during a blackout – was switched on just 60 days after the contract to build it was signed.

So ways of cutting the use of fossil fuels and reducing their contribution to climate heating, now clearly implicated in Australia’s catastrophe, are within reach.

The battery was commissioned in order to bring greater reliability and stability to the state’s electricity grid, preventing blackouts, improving reliability across the network and helping to even out price spikes.

The state’s efforts to increase its proportion of renewable energy had previously been hampered by freak weather which caused outages, which in turn sparked a political brawl over energy policy. The federal government blamed the supply failures on the use of renewable technologies.

40 days to spare

The state premier challenged the technology entrepreneur Elon Musk,  who replied by saying he would build a massive battery within 100 days of signing the deal. He managed it with 40 days to spare.

His approach − a familiar one in the renewable energy world − was to charge the battery packs when excess power was available and the cost of production very low, and then discharge them when the cost of power production rose.

The world is becoming increasingly reliant on battery power, largely because of the need to reduce carbon in the transport sector; almost 60% of new cars sold in Norway during March 2019 were entirely electric-powered. A recent World Economic Forum (WEF) report expects global battery demand to increase by more than 19 times its current levels in the next decade.

Batteries have historically been a dirty but convenient product, requiring the mining of metals such as nickel and zinc, yet considered disposable; landfills are strewn with these hazardous toxins, with more arriving every day. According to the US Environmental Protection Agency (EPA), each year Americans throw away more than three billion batteries – 180,000 tons of waste.

Yet the WEF report projects that new generation batteries could not only enable 30% of the required reductions in carbon emissions in the transport and power sectors, providing access to electricity to 600 million people who currently have no access; they will also create 10 million safe and sustainable jobs around the world.

Batteries will probably play a large part in future energy supply systems; in 2018, South Australia invested $100 million in a scheme to encourage householders to fit batteries to their solar systems, enabling them to use their own power on site rather than exporting it to the grid. This helps to reduce demand at peak times.

“The federal government blamed the supply failures on the use of renewable technologies”

Electric cars are not the only part of the transportation sector that will be in need of batteries. A number of companies are currently working on electric-powered commercial aircraft designs, and Norway is working on battery technology for shipping, with an all-electric passenger vessel already operating.

The Rapid Transition Alliance (RTA) is a UK-based organisation which argues that humankind must undertake “widespread behaviour change to sustainable lifestyles . . . to live within planetary ecological boundaries and to limit global warming to below 1.5°C”, with the slogan “Evidence-based hope for a warming world”.

It believes there is evidence that batteries can offer hope for Australia  and other countries facing similar lethal threats − provided they absorb several crucial lessons.

First, it says, technological leaps need both the flair of individual effort and the clout of institutional backing if they are to work at scale.

Then behavioural change must be practical and economically viable, because only a small minority of people will ever change for green reasons alone. Simply switching to electricity as a fuel source is not enough: to hit climate targets and maintain a habitable world, there needs to be an absolute reduction in energy consumption.

And finally, as batteries increasingly form part of the energy infrastructure, safeguards must be put in place around the mining involved in obtaining the minerals needed to make them, to ensure that poorer communities in the global South do not pay the price for cutting carbon emissions in richer countries. − Climate News Network

* * * * *

The Rapid Transition Alliance is coordinated by the New Weather Institute, the STEPS Centre at the Institute of  Development Studies, and the School of Global Studies at the University of Sussex, UK. The Climate News Network is partnering with and supported by the Rapid Transition Alliance, and will be reporting regularly on its work. If you would like to see more stories of evidence-based hope for rapid transition, please sign up here.

Do you know a story of rapid transition? If so, we’d like to hear from you. Please send us a brief outline on info@climatenewsnetwork.net. Thank you.

The Australian inferno has yet to reach its worst, but already minds are seeking ways to reduce the bushfire horrors. Could batteries help next time?

LONDON, 9 January, 2020 − With at least 27 human fatalities and a scarcely credible estimate by scientists that more than one billion animals have been killed nationwide by the unprecedented blazes  since September 2019, Australia’s bushfire horrors have stunned the world.

The climate crisis is contributing to the catastrophe, at least to its scale and intensity, whether or not it is its primary cause. And scientists revealed only this month that global heating is causing daily weather change.

But something else happened in Australia in 2019 which could point the way towards a fast route, not for Australia alone but globally, to renewable energy and a safer future.

In the state of South Australia the world’s biggest lithium-ion battery – 129MWh, able to power 30,000 homes for an hour during a blackout – was switched on just 60 days after the contract to build it was signed.

So ways of cutting the use of fossil fuels and reducing their contribution to climate heating, now clearly implicated in Australia’s catastrophe, are within reach.

The battery was commissioned in order to bring greater reliability and stability to the state’s electricity grid, preventing blackouts, improving reliability across the network and helping to even out price spikes.

The state’s efforts to increase its proportion of renewable energy had previously been hampered by freak weather which caused outages, which in turn sparked a political brawl over energy policy. The federal government blamed the supply failures on the use of renewable technologies.

40 days to spare

The state premier challenged the technology entrepreneur Elon Musk,  who replied by saying he would build a massive battery within 100 days of signing the deal. He managed it with 40 days to spare.

His approach − a familiar one in the renewable energy world − was to charge the battery packs when excess power was available and the cost of production very low, and then discharge them when the cost of power production rose.

The world is becoming increasingly reliant on battery power, largely because of the need to reduce carbon in the transport sector; almost 60% of new cars sold in Norway during March 2019 were entirely electric-powered. A recent World Economic Forum (WEF) report expects global battery demand to increase by more than 19 times its current levels in the next decade.

Batteries have historically been a dirty but convenient product, requiring the mining of metals such as nickel and zinc, yet considered disposable; landfills are strewn with these hazardous toxins, with more arriving every day. According to the US Environmental Protection Agency (EPA), each year Americans throw away more than three billion batteries – 180,000 tons of waste.

Yet the WEF report projects that new generation batteries could not only enable 30% of the required reductions in carbon emissions in the transport and power sectors, providing access to electricity to 600 million people who currently have no access; they will also create 10 million safe and sustainable jobs around the world.

Batteries will probably play a large part in future energy supply systems; in 2018, South Australia invested $100 million in a scheme to encourage householders to fit batteries to their solar systems, enabling them to use their own power on site rather than exporting it to the grid. This helps to reduce demand at peak times.

“The federal government blamed the supply failures on the use of renewable technologies”

Electric cars are not the only part of the transportation sector that will be in need of batteries. A number of companies are currently working on electric-powered commercial aircraft designs, and Norway is working on battery technology for shipping, with an all-electric passenger vessel already operating.

The Rapid Transition Alliance (RTA) is a UK-based organisation which argues that humankind must undertake “widespread behaviour change to sustainable lifestyles . . . to live within planetary ecological boundaries and to limit global warming to below 1.5°C”, with the slogan “Evidence-based hope for a warming world”.

It believes there is evidence that batteries can offer hope for Australia  and other countries facing similar lethal threats − provided they absorb several crucial lessons.

First, it says, technological leaps need both the flair of individual effort and the clout of institutional backing if they are to work at scale.

Then behavioural change must be practical and economically viable, because only a small minority of people will ever change for green reasons alone. Simply switching to electricity as a fuel source is not enough: to hit climate targets and maintain a habitable world, there needs to be an absolute reduction in energy consumption.

And finally, as batteries increasingly form part of the energy infrastructure, safeguards must be put in place around the mining involved in obtaining the minerals needed to make them, to ensure that poorer communities in the global South do not pay the price for cutting carbon emissions in richer countries. − Climate News Network

* * * * *

The Rapid Transition Alliance is coordinated by the New Weather Institute, the STEPS Centre at the Institute of  Development Studies, and the School of Global Studies at the University of Sussex, UK. The Climate News Network is partnering with and supported by the Rapid Transition Alliance, and will be reporting regularly on its work. If you would like to see more stories of evidence-based hope for rapid transition, please sign up here.

Do you know a story of rapid transition? If so, we’d like to hear from you. Please send us a brief outline on info@climatenewsnetwork.net. Thank you.

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