Tag Archives: Rainfall

Africa’s resistance grows as climate crisis worsens

Battered by storms and droughts during a tough 2019, Africa’s resistance to the climate crisis left no room for passivity.

LONDON, 29 October, 2020 – Attempting to come to any general conclusions on the state of a vast, varied and complex continent may be a tricky business, but Africa’s resistance to the climate crisis shows it rejects any idea of settling for victimhood.

A new report, State of the Climate in Africa 2019, published by the World Meteorological Organization (WMO), makes that clear.

It reaches some grim conclusions. Increased temperatures, changing rainfall patterns, rising sea levels and more extreme weather are threatening human health and safety across the continent, says the report.

“Climate change is having a growing impact on the African continent, hitting the most vulnerable hardest and contributing to food insecurity, population displacement and stress on water resources”, says Petteri Taalas, the WMO secretary-general.

“In recent months we have seen devastating floods, an invasion of desert locusts and now face the looming spectre of drought because of a La Niña event”, he says. “The human and economic toll has been aggravated by the Covid-19 pandemic.”

Killer cyclone

Drought caused considerable damage in 2019, particularly across southern Africa. Much of East Africa also suffered drought but then, late in the year, there was torrential rain and serious flooding and landslides in the region.

The trend, says the report, is for continuing increases in temperature: 2019 was among the three warmest years ever recorded in Africa. The WMO predicts that rainfall is likely to decrease over northern and southern regions but increase over the Sahel.

There are also likely to be more weather-related extreme events. In March 2019 Cyclone Idai hit the coast of Mozambique and went on to devastate large areas of Malawi, Zimbabwe and surrounding countries.

Described as the most destructive cyclone ever recorded in the southern hemisphere, Idai killed hundreds of people and displaced several hundred thousand.

“Climate change is having a growing impact on the African continent, hitting the most vulnerable hardest”

Sea levels are rising well above the global average in many parts of Africa, the report says. Coastal degradation and erosion is a major challenge, particularly in West Africa. More than 50% of the coastlines in Benin, Côte d’Ivoire, Senegal and Togo are eroding – a trend likely to continue in future years.

The knock-on effects of these changes in climate are considerable. Approximately 60% of the total population of Africa is dependent on agriculture for a living.

Heat and drought, plus flood damage in some areas, are likely to reduce crop productivity. Changes in climate are also leading to pest outbreaks.

In what it describes as the worst case climate change scenario, the report says crop yields could drop by 13% by mid-century across West and Central Africa, 11% in North Africa and 8% in the eastern and southern regions of the continent. Rice and wheat crops would be particularly badly affected.

Combatting the crisis

Increased heat and continually changing rainfall patterns are also likely to lead to the spread of disease – and a fall-off in economic production in many countries.

But the report does point to some positive changes, showing Africa’s resistance to the crisis. Though the continent is responsible for only a small percentage of the world’s greenhouse gas emissions, many countries in Africa are taking measures aimed at tackling climate change.

Solar power is becoming more widespread, with several large-scale projects planned. Early warning systems monitoring the approach of such cataclysmic events as Cyclone Idai are being installed across the continent.
Farm incomes in many areas are increasing, due to the application of more efficient cultivation methods, such as micro-irrigation. But good planning, based on reliable data, is essential, the report says.

“The limited uptake and use of climate information services in development planning and practice in Africa is due in part to the paucity of reliable and timely climate information”, says Vera Songwe, the executive secretary of the United Nations Economic Commission for Africa. – Climate News Network

Battered by storms and droughts during a tough 2019, Africa’s resistance to the climate crisis left no room for passivity.

LONDON, 29 October, 2020 – Attempting to come to any general conclusions on the state of a vast, varied and complex continent may be a tricky business, but Africa’s resistance to the climate crisis shows it rejects any idea of settling for victimhood.

A new report, State of the Climate in Africa 2019, published by the World Meteorological Organization (WMO), makes that clear.

It reaches some grim conclusions. Increased temperatures, changing rainfall patterns, rising sea levels and more extreme weather are threatening human health and safety across the continent, says the report.

“Climate change is having a growing impact on the African continent, hitting the most vulnerable hardest and contributing to food insecurity, population displacement and stress on water resources”, says Petteri Taalas, the WMO secretary-general.

“In recent months we have seen devastating floods, an invasion of desert locusts and now face the looming spectre of drought because of a La Niña event”, he says. “The human and economic toll has been aggravated by the Covid-19 pandemic.”

Killer cyclone

Drought caused considerable damage in 2019, particularly across southern Africa. Much of East Africa also suffered drought but then, late in the year, there was torrential rain and serious flooding and landslides in the region.

The trend, says the report, is for continuing increases in temperature: 2019 was among the three warmest years ever recorded in Africa. The WMO predicts that rainfall is likely to decrease over northern and southern regions but increase over the Sahel.

There are also likely to be more weather-related extreme events. In March 2019 Cyclone Idai hit the coast of Mozambique and went on to devastate large areas of Malawi, Zimbabwe and surrounding countries.

Described as the most destructive cyclone ever recorded in the southern hemisphere, Idai killed hundreds of people and displaced several hundred thousand.

“Climate change is having a growing impact on the African continent, hitting the most vulnerable hardest”

Sea levels are rising well above the global average in many parts of Africa, the report says. Coastal degradation and erosion is a major challenge, particularly in West Africa. More than 50% of the coastlines in Benin, Côte d’Ivoire, Senegal and Togo are eroding – a trend likely to continue in future years.

The knock-on effects of these changes in climate are considerable. Approximately 60% of the total population of Africa is dependent on agriculture for a living.

Heat and drought, plus flood damage in some areas, are likely to reduce crop productivity. Changes in climate are also leading to pest outbreaks.

In what it describes as the worst case climate change scenario, the report says crop yields could drop by 13% by mid-century across West and Central Africa, 11% in North Africa and 8% in the eastern and southern regions of the continent. Rice and wheat crops would be particularly badly affected.

Combatting the crisis

Increased heat and continually changing rainfall patterns are also likely to lead to the spread of disease – and a fall-off in economic production in many countries.

But the report does point to some positive changes, showing Africa’s resistance to the crisis. Though the continent is responsible for only a small percentage of the world’s greenhouse gas emissions, many countries in Africa are taking measures aimed at tackling climate change.

Solar power is becoming more widespread, with several large-scale projects planned. Early warning systems monitoring the approach of such cataclysmic events as Cyclone Idai are being installed across the continent.
Farm incomes in many areas are increasing, due to the application of more efficient cultivation methods, such as micro-irrigation. But good planning, based on reliable data, is essential, the report says.

“The limited uptake and use of climate information services in development planning and practice in Africa is due in part to the paucity of reliable and timely climate information”, says Vera Songwe, the executive secretary of the United Nations Economic Commission for Africa. – Climate News Network

River deltas become even riskier as climate warms

River deltas are among the world’s richest habitats. They are also, increasingly, home to the most vulnerable people.

LONDON, 8 October, 2020 − Already, more than 30 million people worldwide are in danger of catastrophic floods − and now they face further danger from the river deltas which are their homes.

Ocean storm surges which are one threat could wash away their homes, their livelihoods, and even their lives. Another, rising tide levels, could turn their gardens to salt and sap the foundations of their lives. With many more, tropical cyclones could sweep in and literally rain their houses into the sea

What all these vulnerable people − in New Orleans, in Bangkok, in Shanghai, in the mouths of the Ganges-Brahmaputra, in any of more than 2,000 settlements − have in common is that they live on a river delta: that vital, ever-shifting zone where a great river spills its silt into the ocean.

And climate change driven by ever-rising ratios of greenhouse gases in the atmosphere − a consequence of ever-greater reliance on fossil fuels − can only make such hazards ever more dangerous. But the first challenge is: who, exactly, is most at risk? And where?

“To date, no-one has successfully quantified the global population in river deltas and assessed the cumulative impacts from climate change,” said Douglas Edmonds, of the University of Indiana in the US.

Costly endowment

“Since river deltas have long been recognised as hotspots of population growth, and with increasing impacts from climate change, we realised we needed to properly quantify what the cumulative risks are in river deltas.”

Dr Edmonds and his colleagues report in Nature Communications that they assembled a global database of 2,174 delta locations, to identity the populations settled on and around them in 2017, and the topography most at risk.

River deltas add up to perhaps 0.5% of the planet’s land surface, but they are home to 4.5% of the world’s population. Humans have settled on river deltas for at least 7,000 years: the rivers deliver nutrient-rich silts for new farmland, and the river estuaries have provided a focus for regional and international transport, to become some of the world’s greatest cities.

But such riches come at a cost: as the rivers have been contained and engineered, the land cover has changed and the land surface subsided. So as sea levels rise with climate change, deltaic areas could become 50% more vulnerable to coastal flood.

“No-one has successfully quantified the global population in river deltas and assessed the cumulative impacts from climate change”

Precisely because river deltas form at or even below sea level, they are highly prone to storm surges driven by tropical cyclones. And by 2100, these could become from 2% to 11% more intense.

The researchers found that in 2017, around 339m people had made their homes on 710,000 square kilometres of habitable land around river deltas: in this century alone, the population on deltas had grown by 34%.

Of these, 31m lived on floodplains vulnerable to the kind of storm surges that happen once a century. And of this 31m, 92% lived in developing or least-developed economies, often breathing polluted air, with poor housing and limited access to public services such as drainage. So, as usual, the poorest were also the most at risk from climate change.

In fact, as scientists have been warning for a decade or more, coastal flooding is a hazard inevitably on the increase, and an increasingly costly one, worldwide.

Even in the US, floods will become a serial nuisance in many cities and an estimated 13m Americans could eventually become climate refugees.

Very cautious estimates

Climate change is likely to deliver a hotter, wetter world with more soil erosion that could trigger catastrophic delta flooding. Hurricanes and typhoons driven by rising sea temperatures are likely to exact an ever-greater toll on human life and wealth.

The Indiana scientists warn that their estimates of those most at risk and the costs they face are likely to be highly conservative. They did not, for instance, consider the special case of what they call “compound interaction.”

This is sociological shorthand for what could happen when climate-related disaster overtakes those who are poorest, crowded into the least protected and unhealthiest zones of the cities. Altogether, 105m people have settled on the Ganges-Brahmaputra delta, half of them on low-lying farmland. The second most crowded is the Nile delta, with 45m people.

“To effectively prepare for more intense future coastal flooding,” Dr Edmonds said, “we need to reframe it as a problem that disproportionately impacts people on river deltas in developing and least developed economies.” − Climate News Network

River deltas are among the world’s richest habitats. They are also, increasingly, home to the most vulnerable people.

LONDON, 8 October, 2020 − Already, more than 30 million people worldwide are in danger of catastrophic floods − and now they face further danger from the river deltas which are their homes.

Ocean storm surges which are one threat could wash away their homes, their livelihoods, and even their lives. Another, rising tide levels, could turn their gardens to salt and sap the foundations of their lives. With many more, tropical cyclones could sweep in and literally rain their houses into the sea

What all these vulnerable people − in New Orleans, in Bangkok, in Shanghai, in the mouths of the Ganges-Brahmaputra, in any of more than 2,000 settlements − have in common is that they live on a river delta: that vital, ever-shifting zone where a great river spills its silt into the ocean.

And climate change driven by ever-rising ratios of greenhouse gases in the atmosphere − a consequence of ever-greater reliance on fossil fuels − can only make such hazards ever more dangerous. But the first challenge is: who, exactly, is most at risk? And where?

“To date, no-one has successfully quantified the global population in river deltas and assessed the cumulative impacts from climate change,” said Douglas Edmonds, of the University of Indiana in the US.

Costly endowment

“Since river deltas have long been recognised as hotspots of population growth, and with increasing impacts from climate change, we realised we needed to properly quantify what the cumulative risks are in river deltas.”

Dr Edmonds and his colleagues report in Nature Communications that they assembled a global database of 2,174 delta locations, to identity the populations settled on and around them in 2017, and the topography most at risk.

River deltas add up to perhaps 0.5% of the planet’s land surface, but they are home to 4.5% of the world’s population. Humans have settled on river deltas for at least 7,000 years: the rivers deliver nutrient-rich silts for new farmland, and the river estuaries have provided a focus for regional and international transport, to become some of the world’s greatest cities.

But such riches come at a cost: as the rivers have been contained and engineered, the land cover has changed and the land surface subsided. So as sea levels rise with climate change, deltaic areas could become 50% more vulnerable to coastal flood.

“No-one has successfully quantified the global population in river deltas and assessed the cumulative impacts from climate change”

Precisely because river deltas form at or even below sea level, they are highly prone to storm surges driven by tropical cyclones. And by 2100, these could become from 2% to 11% more intense.

The researchers found that in 2017, around 339m people had made their homes on 710,000 square kilometres of habitable land around river deltas: in this century alone, the population on deltas had grown by 34%.

Of these, 31m lived on floodplains vulnerable to the kind of storm surges that happen once a century. And of this 31m, 92% lived in developing or least-developed economies, often breathing polluted air, with poor housing and limited access to public services such as drainage. So, as usual, the poorest were also the most at risk from climate change.

In fact, as scientists have been warning for a decade or more, coastal flooding is a hazard inevitably on the increase, and an increasingly costly one, worldwide.

Even in the US, floods will become a serial nuisance in many cities and an estimated 13m Americans could eventually become climate refugees.

Very cautious estimates

Climate change is likely to deliver a hotter, wetter world with more soil erosion that could trigger catastrophic delta flooding. Hurricanes and typhoons driven by rising sea temperatures are likely to exact an ever-greater toll on human life and wealth.

The Indiana scientists warn that their estimates of those most at risk and the costs they face are likely to be highly conservative. They did not, for instance, consider the special case of what they call “compound interaction.”

This is sociological shorthand for what could happen when climate-related disaster overtakes those who are poorest, crowded into the least protected and unhealthiest zones of the cities. Altogether, 105m people have settled on the Ganges-Brahmaputra delta, half of them on low-lying farmland. The second most crowded is the Nile delta, with 45m people.

“To effectively prepare for more intense future coastal flooding,” Dr Edmonds said, “we need to reframe it as a problem that disproportionately impacts people on river deltas in developing and least developed economies.” − Climate News Network

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.