Tag Archives: Rainfall

Melting Arctic needs new name to match reality

Change in the far north is happening so fast that soon the melting Arctic won’t be arctic any more.

LONDON, 16 September, 2020 − The word Arctic may be up for redefinition. The conditions within the melting Arctic Circle are changing so fast that what was once a frozen seascape could now be entering a new climate regime in which nothing is predictable.

Even in an unusually cold year, the sea ice may not return to the summer limits normal in the last century. For some months of autumn and even winter, rain will fall instead of snow, US scientists report in the journal Nature Climate Change.

“The rate of change is remarkable,” said Laura Landrum, of the US National Centre for Atmospheric Research, who led the study.

“It’s a period of such rapid change that observations of past weather patterns no longer show what you can expect next year. The Arctic is already entering a completely different climate than just a few decades ago.”

She and a colleague looked at four decades of satellite data and ground observations and hundreds of computer simulations to confirm that polar warming is happening at such a rate that any change year to year is no longer within the extremes of the past. Conditions that were once normally changeable are now abnormally so.

“The Arctic is already entering a completely different climate than just a few decades ago … We need to change our definition of what the Arctic is”

Climate in the northern hemisphere is moderated by temperature differences that vary with latitude: between them, a torrid equator and a frozen Arctic drive the prevailing winds and ocean currents and the mix of cloud, sunshine, rainfall, frost, windstorm, dry spells and seasonal flooding in which agriculture, industry and civilisation have evolved for the last 10,000 years.

But as carbon dioxide levels in the atmosphere soar in response to rapidly-increasing use of fossil fuels, the melting Arctic has been warming far more swiftly than the planet as a whole.

The extent of summer sea ice in each of the last 13 years has been lower than any minimum observed since 1979, when systematic observation began. Winters have been warmer, winter sea ice has been reduced, rain has been falling on snow ever earlier.

The climate scientists posed themselves the simple question: “While these changes appear extreme compared with the recent past, are they climate extremes in a statistical sense, or do they represent expected events in a new Arctic climate?”

New climate develops

The answer seems to be: yes. The researchers tested their statistical techniques on five different climate simulations. Each of these showed the sea ice retreating so dramatically that a new climate had emerged some time in the late 20th and early 21st centuries.

The finding fits a pattern of foreboding delivered by recent research. In the last two months, researchers have warned that ice loss in the Arctic regions has been so severe that the region’s most charismatic predator, the polar bear, may be gone by the century’s end.

Another group has warned that the Arctic ocean in late summer may be effectively ice-free within the next 15 years.

One group has concluded that ice loss from Greenland is now at such a rate as to be irreversible, and another has confirmed that the rate of ice melt from the northern hemisphere’s biggest reserve – enough to raise sea levels six or seven metres – last year reached new records.

And this month an international research team reported that the rate of change in the Arctic has exceeded the “worst-case” scenario proposed by climate researchers.

Unknown extremes ahead

Dr Landrum and her colleague report that − if greenhouse gas emissions continue at their present rate − some of their climate forecasts predict a mostly ice-free Arctic for between three and 10 months a year, every year, by the end of the century.

Air temperatures over the ocean in autumn and winter will become warmer before or by mid-century, and then start warming over land in the second half.

In a warmer world, more water will evaporate and fall again as rain. Over Alaska, northern Canada and northern Siberia there will be more rain rather than snow: by mid-century, perhaps an extra 20 to 60 days, and by 2100, perhaps from 60 to an extra 90 days. In some parts of the Arctic, by the century’s end, rain might fall in any month of the year.

“The Arctic is likely to experience extremes in sea ice, temperature and precipitation that are far outside anything we’ve experienced before,” Dr Landrum said. “We need to change our definition of what the Arctic is.” − Climate News Network

Change in the far north is happening so fast that soon the melting Arctic won’t be arctic any more.

LONDON, 16 September, 2020 − The word Arctic may be up for redefinition. The conditions within the melting Arctic Circle are changing so fast that what was once a frozen seascape could now be entering a new climate regime in which nothing is predictable.

Even in an unusually cold year, the sea ice may not return to the summer limits normal in the last century. For some months of autumn and even winter, rain will fall instead of snow, US scientists report in the journal Nature Climate Change.

“The rate of change is remarkable,” said Laura Landrum, of the US National Centre for Atmospheric Research, who led the study.

“It’s a period of such rapid change that observations of past weather patterns no longer show what you can expect next year. The Arctic is already entering a completely different climate than just a few decades ago.”

She and a colleague looked at four decades of satellite data and ground observations and hundreds of computer simulations to confirm that polar warming is happening at such a rate that any change year to year is no longer within the extremes of the past. Conditions that were once normally changeable are now abnormally so.

“The Arctic is already entering a completely different climate than just a few decades ago … We need to change our definition of what the Arctic is”

Climate in the northern hemisphere is moderated by temperature differences that vary with latitude: between them, a torrid equator and a frozen Arctic drive the prevailing winds and ocean currents and the mix of cloud, sunshine, rainfall, frost, windstorm, dry spells and seasonal flooding in which agriculture, industry and civilisation have evolved for the last 10,000 years.

But as carbon dioxide levels in the atmosphere soar in response to rapidly-increasing use of fossil fuels, the melting Arctic has been warming far more swiftly than the planet as a whole.

The extent of summer sea ice in each of the last 13 years has been lower than any minimum observed since 1979, when systematic observation began. Winters have been warmer, winter sea ice has been reduced, rain has been falling on snow ever earlier.

The climate scientists posed themselves the simple question: “While these changes appear extreme compared with the recent past, are they climate extremes in a statistical sense, or do they represent expected events in a new Arctic climate?”

New climate develops

The answer seems to be: yes. The researchers tested their statistical techniques on five different climate simulations. Each of these showed the sea ice retreating so dramatically that a new climate had emerged some time in the late 20th and early 21st centuries.

The finding fits a pattern of foreboding delivered by recent research. In the last two months, researchers have warned that ice loss in the Arctic regions has been so severe that the region’s most charismatic predator, the polar bear, may be gone by the century’s end.

Another group has warned that the Arctic ocean in late summer may be effectively ice-free within the next 15 years.

One group has concluded that ice loss from Greenland is now at such a rate as to be irreversible, and another has confirmed that the rate of ice melt from the northern hemisphere’s biggest reserve – enough to raise sea levels six or seven metres – last year reached new records.

And this month an international research team reported that the rate of change in the Arctic has exceeded the “worst-case” scenario proposed by climate researchers.

Unknown extremes ahead

Dr Landrum and her colleague report that − if greenhouse gas emissions continue at their present rate − some of their climate forecasts predict a mostly ice-free Arctic for between three and 10 months a year, every year, by the end of the century.

Air temperatures over the ocean in autumn and winter will become warmer before or by mid-century, and then start warming over land in the second half.

In a warmer world, more water will evaporate and fall again as rain. Over Alaska, northern Canada and northern Siberia there will be more rain rather than snow: by mid-century, perhaps an extra 20 to 60 days, and by 2100, perhaps from 60 to an extra 90 days. In some parts of the Arctic, by the century’s end, rain might fall in any month of the year.

“The Arctic is likely to experience extremes in sea ice, temperature and precipitation that are far outside anything we’ve experienced before,” Dr Landrum said. “We need to change our definition of what the Arctic is.” − Climate News Network

Mass migration set to increase as world warms

Climate change is now driving mass migration, which will only worsen unless governments take global heating seriously.

LONDON, 15 September, 2020 −There is strong evidence that deteriorating environments caused by climate change are driving millions of people to resort to mass migration in their search for a better life, both within countries and across borders.

As temperatures rise these migrations will only increase, particularly in Latin America and India, which is predicted to overtake China as the country with the largest population by 2025.

An analysis of environment and migration, published in Nature Climate Change, of 30 studies of individual countries across the world shows that there is no one single factor that drives migration.

But most research has found that environmental hazards have a major influence. Rising temperature levels, changes in rainfall and single sudden events like hurricanes are all triggers.

Policies for improvement

The analysis, by the International Institute for Applied Systems Analysis (IIASA) in Austria and research partners across Europe, was undertaken to try to inform policy makers about how to avert mass human migration.

It points out that two of the most high-profile mass migration episodes in recent times – the Syrian refugee crisis in 2015 and the “migrant caravan” from Central America to the United States in 2018 – have been partly attributed to severe droughts in the countries concerned.

While some studies conclude that environmental factors were not the main driver of migration, most thought it was one of the primary causes. The analysis says governments should expect significantly higher migration flows in the future.

Perhaps surprisingly, given the publicity surrounding the issue, migrations were not centred on poor people trying to enter rich nations in Europe or North America. Instead, most movements were from the countryside to urban areas in the same country, particularly in agriculturally dependent countries, or from one middle-income country to another.

“The best way to protect those affected is to stabilise the global climate by rapidly reducing greenhouse gas emissions from burning fossil fuels”

People with particularly low incomes normally stayed where they were,  despite environmental pressures, because they had no way of financing a move, while richer people had the means to adapt to new circumstances and so they also stayed put.

“Environmental factors can drive migration, but the size of the effects depends on the particular economic and socio-political conditions in the countries,” explains the lead author Roman Hoffmann, from Germany’s Potsdam Institute for Climate Impact Research (PIK).

“In both low and high income countries, environmental impacts on migration are weaker – presumably because either people are too poor to leave and therefore essentially become trapped or, in wealthy countries, they have enough financial means to absorb the consequences. It is mainly in middle-income regions and those with a dependency on agriculture that we see strong effects.”

IIASA predicts future higher levels of environmental migration for countries in Central America, the Caribbean, Brazil and Argentina. In Africa it is the Sahel region south of the Sahara that is already drying out, and East Africa that has the highest potential for people migrating because of climate change.

Eyes on India

Perhaps the most disturbing prediction is that India, with 1.3 billion people and soon to be the most populous country in the world, is likely to see large migrations. The heat and floods in the country are already killing hundreds of people a year, and many millions who are still dependent on subsistence agriculture are struggling with changing climate conditions.

“Our research suggests that populations in Latin America and the Caribbean, several countries in sub-Saharan Africa – especially in the Sahel region and East Africa – as well as western, southern and south-east Asia, are particularly at risk,” says co-author Anna Dimitrova from the Vienna Institute of Demography of the Austrian Academy of Sciences.

While the report is aimed at preparing governments for migrations that will inevitably happen in the future, with difficult consequences for both the migrants and the host country, the research suggests the best way of averting the coming crisis is to tackle climate change and reduce further rises in temperatures.

“The best way to protect those affected is to stabilise the global climate by rapidly reducing greenhouse gas emissions from burning fossil fuels as well as simultaneously to enhance adaptive capacity, such as through improving human capital,” says Jesus Crespo Cuaresma, a researcher with the IIASA World Population Program and professor of economics at the Vienna University of Economics and Business. − Climate News Network

Climate change is now driving mass migration, which will only worsen unless governments take global heating seriously.

LONDON, 15 September, 2020 −There is strong evidence that deteriorating environments caused by climate change are driving millions of people to resort to mass migration in their search for a better life, both within countries and across borders.

As temperatures rise these migrations will only increase, particularly in Latin America and India, which is predicted to overtake China as the country with the largest population by 2025.

An analysis of environment and migration, published in Nature Climate Change, of 30 studies of individual countries across the world shows that there is no one single factor that drives migration.

But most research has found that environmental hazards have a major influence. Rising temperature levels, changes in rainfall and single sudden events like hurricanes are all triggers.

Policies for improvement

The analysis, by the International Institute for Applied Systems Analysis (IIASA) in Austria and research partners across Europe, was undertaken to try to inform policy makers about how to avert mass human migration.

It points out that two of the most high-profile mass migration episodes in recent times – the Syrian refugee crisis in 2015 and the “migrant caravan” from Central America to the United States in 2018 – have been partly attributed to severe droughts in the countries concerned.

While some studies conclude that environmental factors were not the main driver of migration, most thought it was one of the primary causes. The analysis says governments should expect significantly higher migration flows in the future.

Perhaps surprisingly, given the publicity surrounding the issue, migrations were not centred on poor people trying to enter rich nations in Europe or North America. Instead, most movements were from the countryside to urban areas in the same country, particularly in agriculturally dependent countries, or from one middle-income country to another.

“The best way to protect those affected is to stabilise the global climate by rapidly reducing greenhouse gas emissions from burning fossil fuels”

People with particularly low incomes normally stayed where they were,  despite environmental pressures, because they had no way of financing a move, while richer people had the means to adapt to new circumstances and so they also stayed put.

“Environmental factors can drive migration, but the size of the effects depends on the particular economic and socio-political conditions in the countries,” explains the lead author Roman Hoffmann, from Germany’s Potsdam Institute for Climate Impact Research (PIK).

“In both low and high income countries, environmental impacts on migration are weaker – presumably because either people are too poor to leave and therefore essentially become trapped or, in wealthy countries, they have enough financial means to absorb the consequences. It is mainly in middle-income regions and those with a dependency on agriculture that we see strong effects.”

IIASA predicts future higher levels of environmental migration for countries in Central America, the Caribbean, Brazil and Argentina. In Africa it is the Sahel region south of the Sahara that is already drying out, and East Africa that has the highest potential for people migrating because of climate change.

Eyes on India

Perhaps the most disturbing prediction is that India, with 1.3 billion people and soon to be the most populous country in the world, is likely to see large migrations. The heat and floods in the country are already killing hundreds of people a year, and many millions who are still dependent on subsistence agriculture are struggling with changing climate conditions.

“Our research suggests that populations in Latin America and the Caribbean, several countries in sub-Saharan Africa – especially in the Sahel region and East Africa – as well as western, southern and south-east Asia, are particularly at risk,” says co-author Anna Dimitrova from the Vienna Institute of Demography of the Austrian Academy of Sciences.

While the report is aimed at preparing governments for migrations that will inevitably happen in the future, with difficult consequences for both the migrants and the host country, the research suggests the best way of averting the coming crisis is to tackle climate change and reduce further rises in temperatures.

“The best way to protect those affected is to stabilise the global climate by rapidly reducing greenhouse gas emissions from burning fossil fuels as well as simultaneously to enhance adaptive capacity, such as through improving human capital,” says Jesus Crespo Cuaresma, a researcher with the IIASA World Population Program and professor of economics at the Vienna University of Economics and Business. − Climate News Network

Slightest heat increase magnifies hurricane risk

The poorer and more vulnerable you are, the greater your hurricane risk. Even a tiny heat rise can spell disaster.

LONDON, 11 September, 2020 – Any climate change at all will mean a hurricane risk for the storm-prone Caribbean, even if global average temperatures are contained to a rise of no more than 1.5°C by 2100. But a rise of 2°C could be disastrous: the hurricane hazard could grow fivefold.

The figures – each representing a rise above the long-term average for most of human history – are significant. In 2015 195 nations, including the US, signed up to the Paris Agreement – a promise to contain the rise in global heating to “well below 2°C” by the century’s end. The undeclared but widely-understood intention was a limit of 1.5°C.

In the last century, in response to a rise in carbon dioxide emissions from fossil fuel use, planetary average temperatures have already risen by 1°C, and the Atlantic states of the US and the islands of the Caribbean have been hit by a series of ever more devastating windstorms, as ocean temperatures warm and make hurricanes more probable.

And researchers warn that as global heating continues – with forecasts of a rise of more than 3°C by 2100 – more are on the way.

But the US is wealthy and resilient. British scientists report in the journal Environmental Research Letters that they decided to take a look at the probability of windstorm and heavy rainfall assault on the Caribbean, where half of the 44 million people of the archipelago live within 1.5kms of the coast, and where devastation can be so intense it could take six years to recover.

“The findings are alarming and illustrate the urgent need to tackle global warming to reduce the likelihood of extreme rainfall events”

So they used computer simulations to generate thousands of synthetic hurricanes, under three climate scenarios: present day conditions; a world that kept global heating to no more than 1.5C; and one in which nations let rip and hit the 2°C limit.

They found that extreme rainfall events of the kind which typically happen once every hundred years at present do indeed become more numerous in a world that sticks to its implicit Paris promise. But in a 2°C warmer world, calamitous hurricanes became five times more frequent.

When Hurricane Maria hit Puerto Rico in 2017, it delivered a quarter of a year’s average rainfall all at once, with appalling consequences. In a two-degree warmer world, such a storm could happen every 43 years. The storm that hit the Bahamas in 2019 could become 4.5 times more likely.

“The findings are alarming and illustrate the urgent need to tackle global warming to reduce the likelihood of extreme rainfall events and their catastrophic consequences, particularly for poorer countries which take many years to recover,” said Emily Vosper of the University of Bristol, who led the study.

“We expected extreme hurricanes to be more prevalent in the 2°C global warming scenario, but the scale of the projected increases was surprising, and should serve as a stark warning across the globe, underscoring the importance of keeping climate change under control.” – Climate News Network

The poorer and more vulnerable you are, the greater your hurricane risk. Even a tiny heat rise can spell disaster.

LONDON, 11 September, 2020 – Any climate change at all will mean a hurricane risk for the storm-prone Caribbean, even if global average temperatures are contained to a rise of no more than 1.5°C by 2100. But a rise of 2°C could be disastrous: the hurricane hazard could grow fivefold.

The figures – each representing a rise above the long-term average for most of human history – are significant. In 2015 195 nations, including the US, signed up to the Paris Agreement – a promise to contain the rise in global heating to “well below 2°C” by the century’s end. The undeclared but widely-understood intention was a limit of 1.5°C.

In the last century, in response to a rise in carbon dioxide emissions from fossil fuel use, planetary average temperatures have already risen by 1°C, and the Atlantic states of the US and the islands of the Caribbean have been hit by a series of ever more devastating windstorms, as ocean temperatures warm and make hurricanes more probable.

And researchers warn that as global heating continues – with forecasts of a rise of more than 3°C by 2100 – more are on the way.

But the US is wealthy and resilient. British scientists report in the journal Environmental Research Letters that they decided to take a look at the probability of windstorm and heavy rainfall assault on the Caribbean, where half of the 44 million people of the archipelago live within 1.5kms of the coast, and where devastation can be so intense it could take six years to recover.

“The findings are alarming and illustrate the urgent need to tackle global warming to reduce the likelihood of extreme rainfall events”

So they used computer simulations to generate thousands of synthetic hurricanes, under three climate scenarios: present day conditions; a world that kept global heating to no more than 1.5C; and one in which nations let rip and hit the 2°C limit.

They found that extreme rainfall events of the kind which typically happen once every hundred years at present do indeed become more numerous in a world that sticks to its implicit Paris promise. But in a 2°C warmer world, calamitous hurricanes became five times more frequent.

When Hurricane Maria hit Puerto Rico in 2017, it delivered a quarter of a year’s average rainfall all at once, with appalling consequences. In a two-degree warmer world, such a storm could happen every 43 years. The storm that hit the Bahamas in 2019 could become 4.5 times more likely.

“The findings are alarming and illustrate the urgent need to tackle global warming to reduce the likelihood of extreme rainfall events and their catastrophic consequences, particularly for poorer countries which take many years to recover,” said Emily Vosper of the University of Bristol, who led the study.

“We expected extreme hurricanes to be more prevalent in the 2°C global warming scenario, but the scale of the projected increases was surprising, and should serve as a stark warning across the globe, underscoring the importance of keeping climate change under control.” – Climate News Network

Rivers flood, seas rise – and land faces erosion

Polar melting cannot be separated from farmland soil erosion and estuarine flooding. All are part of climate change.

LONDON, 7 September, 2020 – Climate heating often ensures that calamities don’t come singly: so don’t forget what erosion can do.

In a warmer world the glaciers will melt ever faster to raise global sea levels ever higher. In a wetter world, more and more topsoil will be swept off the farmlands and downriver into the ever-rising seas.

And the pay-off of silt-laden rivers and rising sea levels could be catastrophic floods, as swollen rivers suddenly change course. Since many of the world’s greatest cities are built on river estuaries, lives and economies will be at risk.

Three new studies in two journals deliver a sharp reminder that the consequences of global heating are not straightforward: the world responds to change in unpredictable ways.

First: the melting of the ice sheets and the mountain glaciers. Researchers warn in the journal Nature Climate Change that if the loss of ice from Antarctica, Greenland and the frozen rivers continues, then climate forecasters and government agencies will have to think again: sea levels could rise to at least 17cms higher than the worst predictions so far.

“Avulsions are the earthquakes of rivers. They are sudden and sometimes catastrophic. We are trying to understand where and when the next avulsions will occur”

That means an additional 16 million people at hazard from estuarine floods and storm surges.

In the last 30 years, the flow from the Antarctic ice cap has raised sea levels by 7.2mm, and from Greenland by 10.6mm. Every year, the world’s oceans are 4mm higher than they were the year before.

“Although we anticipated the ice sheets would lose increasing amounts of ice in response to the warming of the oceans and the atmosphere, the rate at which they are melting has accelerated faster than we could have imagined,” said Tom Slater of the University of Leeds, in the UK, who led the research.

“The melting is overtaking the climate models we use to guide us, and we are in danger of being unprepared for the risks posed by sea level rise.”

Dr Slater and his colleagues are the third team to warn in the last month that observations of climate already match the worst-case scenarios dreamed up by forecasters preparing for a range of possible climate outcomes.

Erosion risk rises

The latest reading of glacial melt rates suggests that the risk of storm surges for many of the world’s greatest cities will double by the close of the century. But coastal cities – and the farmers who already work 38% of the terrestrial surface to feed almost 8bn people – have another more immediate problem.

In a warmer world, more water evaporates. In a warmer atmosphere, the capacity of the air to hold moisture also increases, so along with more intense droughts, heavier rainfall is on the way for much of the world. And the heavier the rain, or the more prolonged the drought, the higher the risk of soil erosion.

In 2015 the world’s farmers and foresters watched 43 billion tonnes of topsoil wash away from hillsides or blow away from tilled land and into the sea. By 2070, this burden of silt swept away by water or blown by wind will have risen by between 30% and 66%: probably more than 28 bn tons of additional loss.

This could only impoverish the farmland, according to a study by Swiss scientists in the Proceedings of the National Academy of Sciences. It could also impoverish people, communities and countries. The worst hit could be in the less developed nations of the tropics and subtropics.

But the flow of ever-higher silt levels into ever-rising seas also raises a new hazard: hydrologists call it river avulsion. It’s a simple and natural process. As conditions change, so rivers will naturally change their flow to spill over new floodplains and extend coastal lands.

Survival in question

But river avulsions can also be helped along by rising sea levels. Since 10% of humanity is crowded into rich, fertile delta lands, and since some of the deadliest floods in human history – two in China in 1887 and 1931 claimed six million lives – have been caused by river avulsions, the question becomes a matter of life and death.

US scientists report, also in the Proceedings of the National Academy of Sciences, that rising sea levels alone could make abrupt river avulsion more probable, especially as delta lands could be subsiding, because of groundwater and other extraction.

The dangers of avulsion are affected by the rate of sediment deposit in the river channels, and this is likely to rise with sea levels. This in turn raises the level of the river and eventually a breach of a levee or other flood defence will force the river to find a swifter, steeper path to the sea.

Cities such as New Orleans and the coastal communities of the Mississippi delta are already vulnerable. “Avulsions are the earthquakes of rivers,” said Michael Lamb, of California Institute of Technology, one of the authors.

“They are sudden and sometimes catastrophic natural events that occur with statistical regularity, shifting the direction of major rivers. We are trying to understand where and when the next avulsions will occur.” – Climate News Network

Polar melting cannot be separated from farmland soil erosion and estuarine flooding. All are part of climate change.

LONDON, 7 September, 2020 – Climate heating often ensures that calamities don’t come singly: so don’t forget what erosion can do.

In a warmer world the glaciers will melt ever faster to raise global sea levels ever higher. In a wetter world, more and more topsoil will be swept off the farmlands and downriver into the ever-rising seas.

And the pay-off of silt-laden rivers and rising sea levels could be catastrophic floods, as swollen rivers suddenly change course. Since many of the world’s greatest cities are built on river estuaries, lives and economies will be at risk.

Three new studies in two journals deliver a sharp reminder that the consequences of global heating are not straightforward: the world responds to change in unpredictable ways.

First: the melting of the ice sheets and the mountain glaciers. Researchers warn in the journal Nature Climate Change that if the loss of ice from Antarctica, Greenland and the frozen rivers continues, then climate forecasters and government agencies will have to think again: sea levels could rise to at least 17cms higher than the worst predictions so far.

“Avulsions are the earthquakes of rivers. They are sudden and sometimes catastrophic. We are trying to understand where and when the next avulsions will occur”

That means an additional 16 million people at hazard from estuarine floods and storm surges.

In the last 30 years, the flow from the Antarctic ice cap has raised sea levels by 7.2mm, and from Greenland by 10.6mm. Every year, the world’s oceans are 4mm higher than they were the year before.

“Although we anticipated the ice sheets would lose increasing amounts of ice in response to the warming of the oceans and the atmosphere, the rate at which they are melting has accelerated faster than we could have imagined,” said Tom Slater of the University of Leeds, in the UK, who led the research.

“The melting is overtaking the climate models we use to guide us, and we are in danger of being unprepared for the risks posed by sea level rise.”

Dr Slater and his colleagues are the third team to warn in the last month that observations of climate already match the worst-case scenarios dreamed up by forecasters preparing for a range of possible climate outcomes.

Erosion risk rises

The latest reading of glacial melt rates suggests that the risk of storm surges for many of the world’s greatest cities will double by the close of the century. But coastal cities – and the farmers who already work 38% of the terrestrial surface to feed almost 8bn people – have another more immediate problem.

In a warmer world, more water evaporates. In a warmer atmosphere, the capacity of the air to hold moisture also increases, so along with more intense droughts, heavier rainfall is on the way for much of the world. And the heavier the rain, or the more prolonged the drought, the higher the risk of soil erosion.

In 2015 the world’s farmers and foresters watched 43 billion tonnes of topsoil wash away from hillsides or blow away from tilled land and into the sea. By 2070, this burden of silt swept away by water or blown by wind will have risen by between 30% and 66%: probably more than 28 bn tons of additional loss.

This could only impoverish the farmland, according to a study by Swiss scientists in the Proceedings of the National Academy of Sciences. It could also impoverish people, communities and countries. The worst hit could be in the less developed nations of the tropics and subtropics.

But the flow of ever-higher silt levels into ever-rising seas also raises a new hazard: hydrologists call it river avulsion. It’s a simple and natural process. As conditions change, so rivers will naturally change their flow to spill over new floodplains and extend coastal lands.

Survival in question

But river avulsions can also be helped along by rising sea levels. Since 10% of humanity is crowded into rich, fertile delta lands, and since some of the deadliest floods in human history – two in China in 1887 and 1931 claimed six million lives – have been caused by river avulsions, the question becomes a matter of life and death.

US scientists report, also in the Proceedings of the National Academy of Sciences, that rising sea levels alone could make abrupt river avulsion more probable, especially as delta lands could be subsiding, because of groundwater and other extraction.

The dangers of avulsion are affected by the rate of sediment deposit in the river channels, and this is likely to rise with sea levels. This in turn raises the level of the river and eventually a breach of a levee or other flood defence will force the river to find a swifter, steeper path to the sea.

Cities such as New Orleans and the coastal communities of the Mississippi delta are already vulnerable. “Avulsions are the earthquakes of rivers,” said Michael Lamb, of California Institute of Technology, one of the authors.

“They are sudden and sometimes catastrophic natural events that occur with statistical regularity, shifting the direction of major rivers. We are trying to understand where and when the next avulsions will occur.” – Climate News Network

Less rain will fall during Mediterranean winters

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

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

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

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

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

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

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

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

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

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

High pressure grows

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

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

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

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

Frequent warnings

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

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

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

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

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

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

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

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

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

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

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

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

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

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

High pressure grows

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

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

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

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

Frequent warnings

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

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

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

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

Climate change caused havoc 2000 years ago

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

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

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

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

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

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

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

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

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

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

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

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

Climate’s role

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Climate’s role

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

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

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

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

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

The wetter world ahead will suffer worse droughts

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

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

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

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

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

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

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

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

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

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

Search for precision

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Search for precision

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

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

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

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

Oxford basks in 140-year-old sunshine record

The ancient UK city of Oxford has registered a month-long sunshine record, the sunniest in nearly 150 years.

OXFORD, 4 June, 2020 – So far this year many parts of the world have seen weather records broken, and not always happily, as floods, storms, heat, cold, drought and more reach new extremes – but, in the temperate United Kingdom, swept frequently by Atlantic storms and Arctic gales, a sunshine record is something to marvel at.

That’s what has just been the experience of the city of Oxford, home not only to an ancient university but to a collection of the longest single-site weather records in the UK, with worldwide relevance.

The university’s Radcliffe Meteorological Station has measured a new record for sunshine. The total for the month just gone was 331.7 hours, making May 2020 the sunniest calendar month in the city since sunshine records began in February 1880, and far beyond the previous holder of the title, July 1911, with its total of 310.4 hours.

Oxford’s record May sunshine was 173% higher than the city’s long-term average total sunshine for the month, 192 hours. It was also higher than the long-term average May sunshine hours for Seville and Malaga (approximately 300hrs each ) in southern Spain.

“You can smell the burning card and sometimes see a small smoke trail. It’s a beautiful and wonderfully simple yet very clever device”

Oxford’s statistics for the months from March to May show as well that spring 2020 has been far sunnier than anything measured in previous years, with 59.3 more hours of sunshine than the previous record, set in 1990.

This sequence of long sunny days has meant something else as well: an almost total absence of rain in Oxford, where rainfall records go back as far as 1767 (though in a different part of the city for the first five years). This month was the driest May since 1795 – only 3.5mm accumulated in the rain gauge.

The Radcliffe station measures sunshine with a robust device invented in 1853, called a Campbell–Stokes recorder, or a Stokes sphere. The original design consisted of a glass sphere set into a wooden bowl, on which the sun burnt a trace.

A modification replaced the bowl with a metal housing and a card holder set behind the sphere. The device, still in use almost unchanged after nearly 170 years, records the hours of sunshine bright enough to burn a hole through the card.

International worth

Thomas Caton Harrison, a doctoral student at the University of Oxford, collected the final figures on 1 June to establish the previous day’s sunshine reading. He said: “You can smell the burning card and sometimes see a small smoke trail. It’s a beautiful and wonderfully simple yet very clever device.”

The Radcliffe station has a unique place in both UK and international weather observation. Record-keeping began here in 1772, and an unbroken daily air temperature record has existed since November 1813. The daily rainfall record runs from January 1827, and sunshine from February 1880. These are the longest single-site weather records in the UK, and amongst the longest in the world.

They are especially valuable because the instruments in use and their exposure have been fully documented throughout the record. The station, based at Green Templeton College, has been managed by the university’s School of Geography and the Environment since 1935.

For more details see Oxford Weather and Climate since 1767, published by Oxford University Press in 2019. The book provides an analysis of the weather records from the Radcliffe Meteorological Station, one of the most detailed accounts for any city in the world. – Climate News Network

* * * * * * *

Ian Curtis is Development Officer of the School of Geography and the Environment, University of Oxford.

The ancient UK city of Oxford has registered a month-long sunshine record, the sunniest in nearly 150 years.

OXFORD, 4 June, 2020 – So far this year many parts of the world have seen weather records broken, and not always happily, as floods, storms, heat, cold, drought and more reach new extremes – but, in the temperate United Kingdom, swept frequently by Atlantic storms and Arctic gales, a sunshine record is something to marvel at.

That’s what has just been the experience of the city of Oxford, home not only to an ancient university but to a collection of the longest single-site weather records in the UK, with worldwide relevance.

The university’s Radcliffe Meteorological Station has measured a new record for sunshine. The total for the month just gone was 331.7 hours, making May 2020 the sunniest calendar month in the city since sunshine records began in February 1880, and far beyond the previous holder of the title, July 1911, with its total of 310.4 hours.

Oxford’s record May sunshine was 173% higher than the city’s long-term average total sunshine for the month, 192 hours. It was also higher than the long-term average May sunshine hours for Seville and Malaga (approximately 300hrs each ) in southern Spain.

“You can smell the burning card and sometimes see a small smoke trail. It’s a beautiful and wonderfully simple yet very clever device”

Oxford’s statistics for the months from March to May show as well that spring 2020 has been far sunnier than anything measured in previous years, with 59.3 more hours of sunshine than the previous record, set in 1990.

This sequence of long sunny days has meant something else as well: an almost total absence of rain in Oxford, where rainfall records go back as far as 1767 (though in a different part of the city for the first five years). This month was the driest May since 1795 – only 3.5mm accumulated in the rain gauge.

The Radcliffe station measures sunshine with a robust device invented in 1853, called a Campbell–Stokes recorder, or a Stokes sphere. The original design consisted of a glass sphere set into a wooden bowl, on which the sun burnt a trace.

A modification replaced the bowl with a metal housing and a card holder set behind the sphere. The device, still in use almost unchanged after nearly 170 years, records the hours of sunshine bright enough to burn a hole through the card.

International worth

Thomas Caton Harrison, a doctoral student at the University of Oxford, collected the final figures on 1 June to establish the previous day’s sunshine reading. He said: “You can smell the burning card and sometimes see a small smoke trail. It’s a beautiful and wonderfully simple yet very clever device.”

The Radcliffe station has a unique place in both UK and international weather observation. Record-keeping began here in 1772, and an unbroken daily air temperature record has existed since November 1813. The daily rainfall record runs from January 1827, and sunshine from February 1880. These are the longest single-site weather records in the UK, and amongst the longest in the world.

They are especially valuable because the instruments in use and their exposure have been fully documented throughout the record. The station, based at Green Templeton College, has been managed by the university’s School of Geography and the Environment since 1935.

For more details see Oxford Weather and Climate since 1767, published by Oxford University Press in 2019. The book provides an analysis of the weather records from the Radcliffe Meteorological Station, one of the most detailed accounts for any city in the world. – Climate News Network

* * * * * * *

Ian Curtis is Development Officer of the School of Geography and the Environment, University of Oxford.

Pandemic and climate extremes hit India together

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

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

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

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

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

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

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

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

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

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

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

Assam struck

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

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

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

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

* * * * * * *

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

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

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

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

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

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

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

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

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

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

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

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

Assam struck

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

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

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

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

* * * * * * *

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

Nuclear tests affected the weather 60 years ago

Cold War nuclear tests did change the weather in the 1960s. The Earth did not catch fire, but a hard rain did begin to fall.

LONDON, 19 May, 2020 – Sixty years on, British scientists have confirmed a once-popular belief: that atmospheric nuclear tests of early weapons under development affected the daily weather. A new study of  weather records from 1962 to 1964 reveals the signature of experimental atomic and thermonuclear explosions during the early days of the Cold War.

The scientists measured atmospheric electric charge and cloud data to find that on those days when radioactively-generated electric charge was higher, clouds were thicker and there was up to a quarter more rain than on those days when charge was low.

The climate impact of nuclear detonations may not have been as devastating as many older lay people appeared to think at the time, and some good came of the tests: researchers who studied radiation distribution as it spread around the planet from weapons test sites built up a body of data that delivered a new way to follow atmospheric circulation patterns.

“We have now re-used this data to examine the effect on rainfall,” said Giles Harrison of the University of Reading in the UK. “The politically charged atmosphere of the Cold War led to a nuclear arms race and worldwide anxiety. Decades later, that global cloud has yielded a silver lining, in giving us a unique way to study how electric charge affects rain.”

Between 1945 and 1980 US, Soviet, British and French governments exploded 510 megatons of nuclear weaponry underground, under water and in the lower and upper atmosphere. Of this, 428 megatons – the equivalent of 29,000 bombs of the size dropped onto Hiroshima in Japan at the end of the Second World War – was in the open air, and the greatest concentration of tests was in the late 1950s and early 1960s.

Weather grumbles

Scientists began to collect strontium-90 isotopes and other radioactive fission products in the rain that fell after such tests. By 1960, people in Europe and the US could be heard grumbling about the supposed impact on the weather of tests carried out 10,000 kilometres away.

British cinemagoers were treated to an improbable vision of climate catastrophe triggered by nuclear tests in the 1961 film The Day the Earth Caught Fire. The US government commissioned the Rand Corporation to deliver an inconclusive report in 1966 on the effect upon weather, but by then an international treaty had banned tests in the atmosphere, in the water and in space.

Very slowly, public concern about radioactive fallout and its consequences for the weather began to fade.

Scientists continued to contemplate the climate effects of nuclear confrontation in other ways: in 1983 US researchers proposed a possible nuclear winter, triggered by radioactive mushroom clouds from burning cities that would reach the stratosphere and dim the sun’s light for a decade.

But long before then, peace and prosperity had created another climatic danger: the accelerating combustion of fossil fuels had begun to raise atmospheric greenhouse gas levels to trigger global warming, and climate scientists began to adopt nuclear yardsticks to measure the effect.

“The atmospheric conditions of 1962-64 were exceptional and it is unlikely they will be repeated, for many reasons”

One calculation is that by flying in jet planes or driving cars or generating electric power, humankind is now adding the equivalent in heat energy of five Hiroshima explosions every second to the world’s atmosphere, thus inexorably altering the global climate.

That has not stopped other scientists from worrying about the chilling effects upon climate and human civilisation of even a limited nuclear  exchange. But the supposed impact of bursts of nuclear radiation upon the weather has been more or less forgotten.

Now Professor Harrison and colleagues have returned to the puzzle in the journal Physical Review Letters, to find that the answer could be disentangled from weather records collected in Kew, near London, and 1000 kms away in Lerwick in the Shetland Islands north-east of Scotland, a site selected because it would be least affected by soot, sulphur particles and other kinds of industrial pollution.

Nuclear radiation ionises the matter in its path to create electrically-charged atoms and molecules. Electric charge changes the way water droplets in clouds collide and combine – think of dramatic thunderstorms, lightning and torrential rain – and this affects the size of the droplets and the volume of rain: that is, the rain doesn’t fall at all until the droplets get big enough.

Usually, the sun does most of the work, but in comparing the weather records from two stations, the researchers were for the first time able to factor in the contribution from Cold War test explosions in the Nevada desert, or the Siberian Arctic, or the faraway south Pacific, on Scottish rainfall between 1962 and 1964.

Difference disappeared

They found 150 days in which atmospheric electricity was high or low, while cloudy in Lerwick: they also found a difference in precipitation which, they say, disappeared once the build-up of nuclear radioactive fallout had vanished.

Their statistical analyses suggest no serious or lasting change, but the connection was there: where radioactivity was high, rainfall increased from 2.1mm per day to 2.6mm – a 24% increase in daily rain. Clouds, too, were thicker.

The study remains as one more piece of the climate jigsaw, as a test of measuring technique, and one more reminder of the lessons still to be learned from the Cold War.

It confirms a deepening understanding of the intricate machinery that delivers the first drops of rain, and ideally scientists won’t get many chances to test their understanding in the same way again.

The authors conclude, in the clipped tones favoured by research publications: “The atmospheric conditions of 1962-64 were exceptional and it is unlikely they will be repeated, for many reasons.” – Climate News Network

Cold War nuclear tests did change the weather in the 1960s. The Earth did not catch fire, but a hard rain did begin to fall.

LONDON, 19 May, 2020 – Sixty years on, British scientists have confirmed a once-popular belief: that atmospheric nuclear tests of early weapons under development affected the daily weather. A new study of  weather records from 1962 to 1964 reveals the signature of experimental atomic and thermonuclear explosions during the early days of the Cold War.

The scientists measured atmospheric electric charge and cloud data to find that on those days when radioactively-generated electric charge was higher, clouds were thicker and there was up to a quarter more rain than on those days when charge was low.

The climate impact of nuclear detonations may not have been as devastating as many older lay people appeared to think at the time, and some good came of the tests: researchers who studied radiation distribution as it spread around the planet from weapons test sites built up a body of data that delivered a new way to follow atmospheric circulation patterns.

“We have now re-used this data to examine the effect on rainfall,” said Giles Harrison of the University of Reading in the UK. “The politically charged atmosphere of the Cold War led to a nuclear arms race and worldwide anxiety. Decades later, that global cloud has yielded a silver lining, in giving us a unique way to study how electric charge affects rain.”

Between 1945 and 1980 US, Soviet, British and French governments exploded 510 megatons of nuclear weaponry underground, under water and in the lower and upper atmosphere. Of this, 428 megatons – the equivalent of 29,000 bombs of the size dropped onto Hiroshima in Japan at the end of the Second World War – was in the open air, and the greatest concentration of tests was in the late 1950s and early 1960s.

Weather grumbles

Scientists began to collect strontium-90 isotopes and other radioactive fission products in the rain that fell after such tests. By 1960, people in Europe and the US could be heard grumbling about the supposed impact on the weather of tests carried out 10,000 kilometres away.

British cinemagoers were treated to an improbable vision of climate catastrophe triggered by nuclear tests in the 1961 film The Day the Earth Caught Fire. The US government commissioned the Rand Corporation to deliver an inconclusive report in 1966 on the effect upon weather, but by then an international treaty had banned tests in the atmosphere, in the water and in space.

Very slowly, public concern about radioactive fallout and its consequences for the weather began to fade.

Scientists continued to contemplate the climate effects of nuclear confrontation in other ways: in 1983 US researchers proposed a possible nuclear winter, triggered by radioactive mushroom clouds from burning cities that would reach the stratosphere and dim the sun’s light for a decade.

But long before then, peace and prosperity had created another climatic danger: the accelerating combustion of fossil fuels had begun to raise atmospheric greenhouse gas levels to trigger global warming, and climate scientists began to adopt nuclear yardsticks to measure the effect.

“The atmospheric conditions of 1962-64 were exceptional and it is unlikely they will be repeated, for many reasons”

One calculation is that by flying in jet planes or driving cars or generating electric power, humankind is now adding the equivalent in heat energy of five Hiroshima explosions every second to the world’s atmosphere, thus inexorably altering the global climate.

That has not stopped other scientists from worrying about the chilling effects upon climate and human civilisation of even a limited nuclear  exchange. But the supposed impact of bursts of nuclear radiation upon the weather has been more or less forgotten.

Now Professor Harrison and colleagues have returned to the puzzle in the journal Physical Review Letters, to find that the answer could be disentangled from weather records collected in Kew, near London, and 1000 kms away in Lerwick in the Shetland Islands north-east of Scotland, a site selected because it would be least affected by soot, sulphur particles and other kinds of industrial pollution.

Nuclear radiation ionises the matter in its path to create electrically-charged atoms and molecules. Electric charge changes the way water droplets in clouds collide and combine – think of dramatic thunderstorms, lightning and torrential rain – and this affects the size of the droplets and the volume of rain: that is, the rain doesn’t fall at all until the droplets get big enough.

Usually, the sun does most of the work, but in comparing the weather records from two stations, the researchers were for the first time able to factor in the contribution from Cold War test explosions in the Nevada desert, or the Siberian Arctic, or the faraway south Pacific, on Scottish rainfall between 1962 and 1964.

Difference disappeared

They found 150 days in which atmospheric electricity was high or low, while cloudy in Lerwick: they also found a difference in precipitation which, they say, disappeared once the build-up of nuclear radioactive fallout had vanished.

Their statistical analyses suggest no serious or lasting change, but the connection was there: where radioactivity was high, rainfall increased from 2.1mm per day to 2.6mm – a 24% increase in daily rain. Clouds, too, were thicker.

The study remains as one more piece of the climate jigsaw, as a test of measuring technique, and one more reminder of the lessons still to be learned from the Cold War.

It confirms a deepening understanding of the intricate machinery that delivers the first drops of rain, and ideally scientists won’t get many chances to test their understanding in the same way again.

The authors conclude, in the clipped tones favoured by research publications: “The atmospheric conditions of 1962-64 were exceptional and it is unlikely they will be repeated, for many reasons.” – Climate News Network