Tag Archives: Flooding

Rising sea levels may make some airports unusable

High flyers could soon have a problem with high water. Rising sea levels could one day shut down airports.

LONDON, 3 February, 2021 − Passengers, prepare for splashdown. Take-off may have to wait for low tide. By 2100, thanks to rising sea levels, around 100 of the world’s airports could be below mean sea level and at least 364 will be vulnerable to flooding.

And that’s assuming the world’s nations keep a promise made in 2015 and confine global heating to no more than 2°C above the average maintained for most of human history. If humans go on burning fossil fuels and clearing forests at the present rate, then at least 572 of the world’s airports could be at risk of flooding from extreme tides, according to a new study in the journal Climate Risk Management.

These things have already happened: in 2018 a typhoon storm surge inundated Kansai International Airport in Osaka Bay, Japan. Superstorm Sandy in 2012 closed New York City’s La Guardia Airport for three days. One-tenth of the planet’s population lives on coastlines less than 10 metres above sea level.

Airports grow up around the great cities: they require flat land and a clear flight path. Coastal flood plains, wetlands and reclaimed land provide exactly that.

Serious risk

“These coastal airports are disproportionately important to the global airline network, and by 2100 between 10% and 20% of all routes will be at risk of disruption,” said Richard Dawson, an engineer at Newcastle University in the United Kingdom. “Sea level rise therefore poses a serious risk to global passenger and freight movements, with considerable cost of damage and disruption.”

He and a colleague looked at the world’s 14,000 airports and helicopter pads to identify 1,238 airports in what geographers call low elevation coastal zones: that is, down by the seaside. Of these, 199, serving 3,436 routes, were in the US; China had 30 airports serving 2,333 routes.

They found that just 20 airports at risk handled more than 800 million passengers in 2018 − approaching a fifth of the world’s passenger traffic that year − and nearly 16 million tonnes of cargo: one-fourth of all the world’s air freight that year. They then started looking at what climate change could do to all that business.

Even before the shutdown of traffic because of the global pandemic, the world’s airlines had been feeling the heat. Research teams have confirmed that ever higher global temperatures mean more atmospheric turbulence at altitude; that wind speed changes will slow flights and raise costs; that extremes of heat could even close airport runways and delay flights for extended periods.

“These coastal airports are disproportionately important to the global airline network, and by 2100 between 10% and 20% of all routes will be at risk of disruption”

Now Professor Dawson and his colleague have compiled a table of hazard rankings for flooded airstrips under a range of climate change scenarios.

Right now, 269 of the world’s airports are at some risk of coastal flooding. This number must rise: by how much, and at what cost, depends on what actions the world takes. But the researchers calculate that by 2100 the risk of disruption could increase 17-fold, or even 69-fold. And because so many important airports are already at or near sea level, up to a fifth of all the world’s routes will be at risk.

And that means higher costs for flood protection, or action to raise airport sites, or relocation. The choice is to adapt or, quite literally, to go under.

“The cost of adaptation will be modest in the context of global infrastructure expenditure,” Professor Dawson said. “However, in some locations the rate of sea level rise, limited economic resources or space for alternative locations will make some airports unviable.” − Climate News Network

High flyers could soon have a problem with high water. Rising sea levels could one day shut down airports.

LONDON, 3 February, 2021 − Passengers, prepare for splashdown. Take-off may have to wait for low tide. By 2100, thanks to rising sea levels, around 100 of the world’s airports could be below mean sea level and at least 364 will be vulnerable to flooding.

And that’s assuming the world’s nations keep a promise made in 2015 and confine global heating to no more than 2°C above the average maintained for most of human history. If humans go on burning fossil fuels and clearing forests at the present rate, then at least 572 of the world’s airports could be at risk of flooding from extreme tides, according to a new study in the journal Climate Risk Management.

These things have already happened: in 2018 a typhoon storm surge inundated Kansai International Airport in Osaka Bay, Japan. Superstorm Sandy in 2012 closed New York City’s La Guardia Airport for three days. One-tenth of the planet’s population lives on coastlines less than 10 metres above sea level.

Airports grow up around the great cities: they require flat land and a clear flight path. Coastal flood plains, wetlands and reclaimed land provide exactly that.

Serious risk

“These coastal airports are disproportionately important to the global airline network, and by 2100 between 10% and 20% of all routes will be at risk of disruption,” said Richard Dawson, an engineer at Newcastle University in the United Kingdom. “Sea level rise therefore poses a serious risk to global passenger and freight movements, with considerable cost of damage and disruption.”

He and a colleague looked at the world’s 14,000 airports and helicopter pads to identify 1,238 airports in what geographers call low elevation coastal zones: that is, down by the seaside. Of these, 199, serving 3,436 routes, were in the US; China had 30 airports serving 2,333 routes.

They found that just 20 airports at risk handled more than 800 million passengers in 2018 − approaching a fifth of the world’s passenger traffic that year − and nearly 16 million tonnes of cargo: one-fourth of all the world’s air freight that year. They then started looking at what climate change could do to all that business.

Even before the shutdown of traffic because of the global pandemic, the world’s airlines had been feeling the heat. Research teams have confirmed that ever higher global temperatures mean more atmospheric turbulence at altitude; that wind speed changes will slow flights and raise costs; that extremes of heat could even close airport runways and delay flights for extended periods.

“These coastal airports are disproportionately important to the global airline network, and by 2100 between 10% and 20% of all routes will be at risk of disruption”

Now Professor Dawson and his colleague have compiled a table of hazard rankings for flooded airstrips under a range of climate change scenarios.

Right now, 269 of the world’s airports are at some risk of coastal flooding. This number must rise: by how much, and at what cost, depends on what actions the world takes. But the researchers calculate that by 2100 the risk of disruption could increase 17-fold, or even 69-fold. And because so many important airports are already at or near sea level, up to a fifth of all the world’s routes will be at risk.

And that means higher costs for flood protection, or action to raise airport sites, or relocation. The choice is to adapt or, quite literally, to go under.

“The cost of adaptation will be modest in the context of global infrastructure expenditure,” Professor Dawson said. “However, in some locations the rate of sea level rise, limited economic resources or space for alternative locations will make some airports unviable.” − Climate News Network

US pays rising costs for climate’s flood damage

America’s rainfall patterns are changing with the global climate − and making catastrophic flood damage even more costly.

LONDON, 21 January, 2021 − Climate change alone has cost the United States a total of $73 billion in flood damage in the last 30 years.

The figure is significant: floods are an expensive fact of life. But Californian scientists are now sure that more than one-third of the costs of US floods must be attributed to the global heating driven by human use of fossil fuels.

The news comes hard on the heels of a second finding: that over the last century, the count of what hydrologists call “extreme streamflow” events in Canada and the US has increased significantly. This confirms that droughts are on the increase − and so are floods.

Such findings matter to engineers and city planners, and to insurers, and each resolves some long-standing uncertainties.

Because floods and droughts are part of the challenge of living close to a constant flow of water, researchers have never been too sure whether costly floods are on the increase or are just more obvious because population growth and urban spread mean that more people with more expensive property are increasingly at risk.

“The shifts towards more extreme events are especially important given the age of our dams, bridges and roads”

A new study in the Proceedings of the National Academy of Sciences settles the matter of rising costs: researchers looked at 6,600 reports of flood damage and rainfall data between 1988 and 2017 and then applied sophisticated mathematical techniques to tease out the contribution from higher precipitation driven by higher average temperatures, driven in turn by ever-higher ratios of carbon dioxide in the atmosphere.

They decided that of the $199bn flood damage costs during those years, human-triggered climate change could account for 36%.

“The fact that extreme precipitation has been increasing and will likely increase is well-known, but what effect that has had on financial damages has been uncertain,” said Frances Davenport, of Stanford University.

“What we find is that, even in states where long-term mean precipitation hasn’t changed, in most cases the wettest events have intensified, increasing the financial damages relative to what would have occurred without the changes in precipitation.”

Higher temperatures mean more evaporation. Higher temperatures mean a bigger burden of water vapour in the atmosphere. So higher rainfall is inevitable.

Variable impacts

But repeated studies have found this will happen unevenly: those places already rainy will see more rain. Other regions can expect longer, more intense dry spells.

A second team of US researchers reports in the journal Science Advances that they looked at streamflow data from 541 North American stations since 1910.

They found that in the US west and south-east, the frequency of “extreme low-flow events” has been on the increase, particularly during summer and autumn. In zones where rivers were likely to be fed by melting snow, there was a discernible rise in flood events. Once again, this is a finding with practical consequences.

“The shifts towards more extreme events are especially important given the age of our dams, bridges and roads,” said Evan Dethier, of Dartmouth College in New Hampshire. “The changes to river flows that we found are important for those who manage or depend on this type of infrastructure.” − Climate News Network

America’s rainfall patterns are changing with the global climate − and making catastrophic flood damage even more costly.

LONDON, 21 January, 2021 − Climate change alone has cost the United States a total of $73 billion in flood damage in the last 30 years.

The figure is significant: floods are an expensive fact of life. But Californian scientists are now sure that more than one-third of the costs of US floods must be attributed to the global heating driven by human use of fossil fuels.

The news comes hard on the heels of a second finding: that over the last century, the count of what hydrologists call “extreme streamflow” events in Canada and the US has increased significantly. This confirms that droughts are on the increase − and so are floods.

Such findings matter to engineers and city planners, and to insurers, and each resolves some long-standing uncertainties.

Because floods and droughts are part of the challenge of living close to a constant flow of water, researchers have never been too sure whether costly floods are on the increase or are just more obvious because population growth and urban spread mean that more people with more expensive property are increasingly at risk.

“The shifts towards more extreme events are especially important given the age of our dams, bridges and roads”

A new study in the Proceedings of the National Academy of Sciences settles the matter of rising costs: researchers looked at 6,600 reports of flood damage and rainfall data between 1988 and 2017 and then applied sophisticated mathematical techniques to tease out the contribution from higher precipitation driven by higher average temperatures, driven in turn by ever-higher ratios of carbon dioxide in the atmosphere.

They decided that of the $199bn flood damage costs during those years, human-triggered climate change could account for 36%.

“The fact that extreme precipitation has been increasing and will likely increase is well-known, but what effect that has had on financial damages has been uncertain,” said Frances Davenport, of Stanford University.

“What we find is that, even in states where long-term mean precipitation hasn’t changed, in most cases the wettest events have intensified, increasing the financial damages relative to what would have occurred without the changes in precipitation.”

Higher temperatures mean more evaporation. Higher temperatures mean a bigger burden of water vapour in the atmosphere. So higher rainfall is inevitable.

Variable impacts

But repeated studies have found this will happen unevenly: those places already rainy will see more rain. Other regions can expect longer, more intense dry spells.

A second team of US researchers reports in the journal Science Advances that they looked at streamflow data from 541 North American stations since 1910.

They found that in the US west and south-east, the frequency of “extreme low-flow events” has been on the increase, particularly during summer and autumn. In zones where rivers were likely to be fed by melting snow, there was a discernible rise in flood events. Once again, this is a finding with practical consequences.

“The shifts towards more extreme events are especially important given the age of our dams, bridges and roads,” said Evan Dethier, of Dartmouth College in New Hampshire. “The changes to river flows that we found are important for those who manage or depend on this type of infrastructure.” − Climate News Network

Fire and flood menace parts of US and Bangladesh

Fire and flood are on the rise. Bangladesh and New York face more flooding: the American West may see more forests burn.

LONDON, 14 December, 2020 − More extreme weather is on the way for the hapless residents of Bangladesh, New York and the western US,  facing the prospect of worsening fire and flood.

There is a new future for New York. By the close of the century, thanks to sea level rise and global heating, parts of it could be swept by hurricane-driven catastrophic floods almost every year.

Things don’t look much brighter for much of Bangladesh. Scientists have recalculated the risk of flooding by the Brahmaputra river system to find that, even without the climate emergency, they had under-estimated the likelihood of devastating floods across the crowded, low-lying landscape.

And far away in the American west, US citizens face yet more and more devastating seasons of fire. The area incinerated by severe fires has increased eight-fold in the last 40 years, thanks to intensifying heat and drought. And thanks to climate change, drought will become more extended and more frequent. The temperatures, too, will go on rising.

All this emerged in just another week of routine climate science, as researchers try to gauge the difficulties to come, for national and civic authorities, for foresters and for farmers.

“The increase in these once-in-a-generation floods is so dramatic because the impact of sea-level rise will create greater flooding, even if the storms today stay the same”

In 2012, Hurricane Sandy hit the US to cause $70bn in damages, and even slammed unexpectedly into New York, to devastate parts of the city. It counted as a once-in-500 years event.

Researchers report in the journal Climatic Change that they looked at the probabilities of more flooding in Jamaica Bay, on Long Island, New York as sea levels rose, along with the sea surface temperatures that drive fiercer storm weather, through the century.

Floods that tend to happen every century could, by 2050, occur every nine years. By 2080 to 2100, they could become annual events. And 500-year events like the 2012 superstorm could by the end of the century happen perhaps once every four years.

“Future projections of the hurricane climatology suggest that climate change would lead to storms that move more slowly and are more intense than we have ever seen before hitting Jamaica Bay,” said Reza Marsooli, an environmental engineer at the Stevens Institute of Technology in Hoboken, New Jersey, a co-author.

“But the increase in these once-in-a-generation or even less frequent floods is so dramatic because the impact of sea-level rise will create greater flooding, even if the storms we are seeing today stayed the same.”

Prepare for worse

The hazard that faces Bangladesh − much of which is at sea level, on fertile floodplain created by the Ganges-Brahmaputra river system − is more insidious.

One of the great waterways of the world, it rises in the Himalayan snows and swells in the monsoon season to flood the rice paddies and replenish farmlands with nourishing sediments. Occasionally the floods become devastating: in 1998, some 70% of the nation was submerged. Floods have recurred, in 2007, 2010 and 2020.

Engineers have been monitoring the flow since the 1950s, and thought they knew the flood probabilities. But US, Australian and Chinese scientists report in the journal Nature Communications that they studied the growth rings in ancient trees to find that Bangladeshis have been living in unusual times: for much of the past 70 years, on the evidence told by old trees along the watershed, the river flow has been unusually dry − the driest in the last 700 years.

“The tree rings suggest that the long-term baseline conditions are much wetter than thought,” said Mukund Palat Rao, of the Lamont-Doherty Earth Observatory at Columbia University in New York, who led the research.

“Whether you consider climate models or natural variability, the message is the same. We should prepare for a higher frequency of flooding than we are currently predicting.”

Forests’ future threatened

In the past 40 years, thanks to global heating driven by ever-higher emissions of greenhouse gases from the combustion of fossil fuels, the state of California has experienced a series of droughts that lasted for years. The fire season too has begun earlier and lasted much longer.

Ecologists report in the journal Geophysical Research Letters that they defined high-severity fires as those that killed 95% of all trees. They then counted the most severe episodes of burning in four great regions of the western US from 1985 to 2017.

They found that by 2017, the area wiped out by severe fires had risen eight times, to more than 2,000 sq kms or 800 sq miles. Much of the tree cover of the US west is adapted to episodes of fire. But the frequency and intensity of recent blazes threatens the future of the forests altogether.

“As more area burns at high severity, the likelihood of conversion to different forest types or even to non-forest increases,” said Sean Parks of the US Forest Service Rocky Mountain Research Station, and the lead author.

“At the same time, the post-fire climate is making it increasingly difficult for seedlings to establish and survive, further reducing the potential for forests to return to their pre-fire condition.” − Climate News Network

Fire and flood are on the rise. Bangladesh and New York face more flooding: the American West may see more forests burn.

LONDON, 14 December, 2020 − More extreme weather is on the way for the hapless residents of Bangladesh, New York and the western US,  facing the prospect of worsening fire and flood.

There is a new future for New York. By the close of the century, thanks to sea level rise and global heating, parts of it could be swept by hurricane-driven catastrophic floods almost every year.

Things don’t look much brighter for much of Bangladesh. Scientists have recalculated the risk of flooding by the Brahmaputra river system to find that, even without the climate emergency, they had under-estimated the likelihood of devastating floods across the crowded, low-lying landscape.

And far away in the American west, US citizens face yet more and more devastating seasons of fire. The area incinerated by severe fires has increased eight-fold in the last 40 years, thanks to intensifying heat and drought. And thanks to climate change, drought will become more extended and more frequent. The temperatures, too, will go on rising.

All this emerged in just another week of routine climate science, as researchers try to gauge the difficulties to come, for national and civic authorities, for foresters and for farmers.

“The increase in these once-in-a-generation floods is so dramatic because the impact of sea-level rise will create greater flooding, even if the storms today stay the same”

In 2012, Hurricane Sandy hit the US to cause $70bn in damages, and even slammed unexpectedly into New York, to devastate parts of the city. It counted as a once-in-500 years event.

Researchers report in the journal Climatic Change that they looked at the probabilities of more flooding in Jamaica Bay, on Long Island, New York as sea levels rose, along with the sea surface temperatures that drive fiercer storm weather, through the century.

Floods that tend to happen every century could, by 2050, occur every nine years. By 2080 to 2100, they could become annual events. And 500-year events like the 2012 superstorm could by the end of the century happen perhaps once every four years.

“Future projections of the hurricane climatology suggest that climate change would lead to storms that move more slowly and are more intense than we have ever seen before hitting Jamaica Bay,” said Reza Marsooli, an environmental engineer at the Stevens Institute of Technology in Hoboken, New Jersey, a co-author.

“But the increase in these once-in-a-generation or even less frequent floods is so dramatic because the impact of sea-level rise will create greater flooding, even if the storms we are seeing today stayed the same.”

Prepare for worse

The hazard that faces Bangladesh − much of which is at sea level, on fertile floodplain created by the Ganges-Brahmaputra river system − is more insidious.

One of the great waterways of the world, it rises in the Himalayan snows and swells in the monsoon season to flood the rice paddies and replenish farmlands with nourishing sediments. Occasionally the floods become devastating: in 1998, some 70% of the nation was submerged. Floods have recurred, in 2007, 2010 and 2020.

Engineers have been monitoring the flow since the 1950s, and thought they knew the flood probabilities. But US, Australian and Chinese scientists report in the journal Nature Communications that they studied the growth rings in ancient trees to find that Bangladeshis have been living in unusual times: for much of the past 70 years, on the evidence told by old trees along the watershed, the river flow has been unusually dry − the driest in the last 700 years.

“The tree rings suggest that the long-term baseline conditions are much wetter than thought,” said Mukund Palat Rao, of the Lamont-Doherty Earth Observatory at Columbia University in New York, who led the research.

“Whether you consider climate models or natural variability, the message is the same. We should prepare for a higher frequency of flooding than we are currently predicting.”

Forests’ future threatened

In the past 40 years, thanks to global heating driven by ever-higher emissions of greenhouse gases from the combustion of fossil fuels, the state of California has experienced a series of droughts that lasted for years. The fire season too has begun earlier and lasted much longer.

Ecologists report in the journal Geophysical Research Letters that they defined high-severity fires as those that killed 95% of all trees. They then counted the most severe episodes of burning in four great regions of the western US from 1985 to 2017.

They found that by 2017, the area wiped out by severe fires had risen eight times, to more than 2,000 sq kms or 800 sq miles. Much of the tree cover of the US west is adapted to episodes of fire. But the frequency and intensity of recent blazes threatens the future of the forests altogether.

“As more area burns at high severity, the likelihood of conversion to different forest types or even to non-forest increases,” said Sean Parks of the US Forest Service Rocky Mountain Research Station, and the lead author.

“At the same time, the post-fire climate is making it increasingly difficult for seedlings to establish and survive, further reducing the potential for forests to return to their pre-fire condition.” − Climate News Network

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

Abnormal heat spreads floods and wildfires globally

From the Arctic Circle to tropical Africa, abnormal heat is bringing mayhem and destruction and costing lives.

LONDON, 17 September, 2020 – Across the planet, abnormal heat is exacting a lethal toll. The west coast of the US is up in flames. Over recent months unprecedented high temperatures have been melting permafrost in Siberia, within the Arctic Circle. Fires have spread; many thousands of acres of taiga have been laid waste.

Across many parts of Africa unseasonable torrential rains are causing loss of life and crops.

Climate scientists are careful about attributing any one severe weather event to climate change until all data is gathered and a proper analysis is made.

But looking at various weather patterns around the world, fundamental changes in climate are happening – most related to big increases in temperature.

Along the western seaboard of the US people are having to cope not only with a prolonged drought but with temperatures which are way above normal.

As the ground and brush at the base of trees dries out, the ideal conditions for wildfires are set.

Over recent days more than 40,000 people in the state of Oregon have been told to evacuate their homes: dozens of people are believed to be missing in the mayhem caused by the fires.

“The debate is over.This is a climate damn emergency. This is real and it’s happening”

Kate Brown, Oregon’s governor, says that over three days recently more than 1,400 square miles of land was destroyed by fire – nearly double the amount burned over a typical year in the state.

“We have never seen this amount of uncontained fire”, said Brown.

“While our state reels from this horrific fire storm of hot weather, high winds and drought conditions, this will not be a one-time event.

“Unfortunately it is the bellwether of the future. We are feeling the acute impacts of climate change.”

Last month a group of Oregon’s leading industrialists launched a court action against Governor Brown, saying she overstepped her authority by introducing measures aimed at cutting carbon emissions in the state.

Further south in California, wildfires continue to burn. The skies of San Francisco and other cities have turned red in recent days. Smoke from the fires is causing severe air quality problems.

Gavin Newsom, California’s governor, launched an angry attack on President Trump and others who are sceptical about climate change, while visiting an area of the state destroyed by fire.

Africa inundated

“The debate is over” said Newsom. “This is a climate damn emergency. This is real and it’s happening.”

Studies say that since the early 1970s California has registered a more than fivefold increase in the annual incidence of forest fires.

A similar growing trend in abnormal heat and wildfires is being recorded in many parts of Siberia: soaring temperatures have been a big factor. In one Siberian town temperatures reached 38°C in mid-June – 18°C above the usual daytime temperature for the time of year.

Less reported on but a cause of death and hardship to some of the world’s poorest countries are floods that have been destroying homes and crops across large areas of the African continent.

In Somalia, still trying to establish itself as a functioning fully independent state in the face of terrorist attacks, nearly a million people have been affected by severe flooding in recent months.

Sudan and Ethiopia have also been subject to widespread flooding.

According to data from the US National Oceanic and Atmospheric Administration (NOAA), torrential rains and floods are affecting both east and west Africa. In Nigeria, Africa’s most populous state, thousands of homes have been destroyed and crops ruined. – Climate News Network

From the Arctic Circle to tropical Africa, abnormal heat is bringing mayhem and destruction and costing lives.

LONDON, 17 September, 2020 – Across the planet, abnormal heat is exacting a lethal toll. The west coast of the US is up in flames. Over recent months unprecedented high temperatures have been melting permafrost in Siberia, within the Arctic Circle. Fires have spread; many thousands of acres of taiga have been laid waste.

Across many parts of Africa unseasonable torrential rains are causing loss of life and crops.

Climate scientists are careful about attributing any one severe weather event to climate change until all data is gathered and a proper analysis is made.

But looking at various weather patterns around the world, fundamental changes in climate are happening – most related to big increases in temperature.

Along the western seaboard of the US people are having to cope not only with a prolonged drought but with temperatures which are way above normal.

As the ground and brush at the base of trees dries out, the ideal conditions for wildfires are set.

Over recent days more than 40,000 people in the state of Oregon have been told to evacuate their homes: dozens of people are believed to be missing in the mayhem caused by the fires.

“The debate is over.This is a climate damn emergency. This is real and it’s happening”

Kate Brown, Oregon’s governor, says that over three days recently more than 1,400 square miles of land was destroyed by fire – nearly double the amount burned over a typical year in the state.

“We have never seen this amount of uncontained fire”, said Brown.

“While our state reels from this horrific fire storm of hot weather, high winds and drought conditions, this will not be a one-time event.

“Unfortunately it is the bellwether of the future. We are feeling the acute impacts of climate change.”

Last month a group of Oregon’s leading industrialists launched a court action against Governor Brown, saying she overstepped her authority by introducing measures aimed at cutting carbon emissions in the state.

Further south in California, wildfires continue to burn. The skies of San Francisco and other cities have turned red in recent days. Smoke from the fires is causing severe air quality problems.

Gavin Newsom, California’s governor, launched an angry attack on President Trump and others who are sceptical about climate change, while visiting an area of the state destroyed by fire.

Africa inundated

“The debate is over” said Newsom. “This is a climate damn emergency. This is real and it’s happening.”

Studies say that since the early 1970s California has registered a more than fivefold increase in the annual incidence of forest fires.

A similar growing trend in abnormal heat and wildfires is being recorded in many parts of Siberia: soaring temperatures have been a big factor. In one Siberian town temperatures reached 38°C in mid-June – 18°C above the usual daytime temperature for the time of year.

Less reported on but a cause of death and hardship to some of the world’s poorest countries are floods that have been destroying homes and crops across large areas of the African continent.

In Somalia, still trying to establish itself as a functioning fully independent state in the face of terrorist attacks, nearly a million people have been affected by severe flooding in recent months.

Sudan and Ethiopia have also been subject to widespread flooding.

According to data from the US National Oceanic and Atmospheric Administration (NOAA), torrential rains and floods are affecting both east and west Africa. In Nigeria, Africa’s most populous state, thousands of homes have been destroyed and crops ruined. – 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

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

Indian law restores once dried-up rivers to villagers

Indian villagers who brought dried-up rivers back to life then had to fight a legal battle to use their water.

LONDON, 7 August, 2020 – Drought and dried-up rivers can spell catastrophe for rural communities that rely on their crops for survival. But villagers in India have shown that both threats can be reversed and livelihoods restored – with the backing of the law.

Having succeeded in restoring their rivers’ flow, the villagers faced another battle with their local government and vested interests which wanted to take over the new water supply for their own use. So they went to court, formed their own “water parliament”, and wrested back control.

The story began back in 1985 in the parched lands of Rajasthan in north-west India, when villagers were suffering acutely because the rivers they relied on to water their crops were running dry. They resorted to building johads, traditional hand-dug earth dams, which capture water in the rainy season so that it can soak into the earth and be retained instead of flooding away uselessly.

Often called natural flood management, this approach mimics the natural process of rivers which become blocked by debris and trees – with the beneficial results seen in the complex ecosystems created by beavers, which build their own dams and thereby prevent flooding downstream while also storing water for the dry season.

The first dam was built at the original source of the Arvari river, which for the first 45 kilometres of its length had stopped flowing at all. It took 375 earth dams before the Arvari started to flow again, and 10 years before it became a perennial river once more.

“The unsustainable use of water in modern agriculture and the demands made on aquifers by conurbations is already at breaking point in many places around the globe”

Success was infectious. Altogether, over those 10 years, the residents of 1,000 villages built more than 8,600 johads and other structures to collect water for use in the dry seasons. Remarkably, five rivers – the Arvari, Ruparel, Sarsa, Bhagani and Jahajwali – began to flow again, their valleys turning green with crops.

The rivers gained in value again. So the government of Rajasthan, seeing an opportunity to make money, claimed ownership, even awarding fishing licences to contractors, who were stopped by furious local people.

Fortunately the courts sided with the protestors and handed control of the river to them after 72 villages formed what they called the Arvari River Parliament to administer the river and allot rights to water resources in a fair manner.

They were lucky: the Indian constitution allows local people to get financial and legal support in cases against perceived injustices. This meant they had access to justice which they could not otherwise have afforded. The system favours local democracy where it can be shown to work.

Over-exploitation

The Rapid Transition Alliance (RTA) is a UK-based organisation which argues that humankind must undertake “widespread behaviour change to sustainable lifestyles … to live within planetary ecological boundaries and to limit global warming to below 1.5°C” (the more stringent limit set by the 2015 Paris Agreement on climate change).

The story of the success of the earth dams is told by the RTA as part of its series publicising global examples of how projects and communities can combat the environmental destruction caused by the effects of climate heating.

The drying-up of water resources, combined with climate change, is one of the key problems of poor river management in many parts of the world. Climates vary markedly, but on rivers in Africa, Europe and the US vital water resources are also drying up, often through over-exploitation as well as drought.

The Alliance says: “The unsustainable use of water in modern agriculture and the demands made on aquifers by conurbations is already at breaking point in many places around the globe. Climate change is exacerbating this with higher temperatures in already dry places.”

Resisting usurpers

It cites a range of schemes used to tackle the problem, similar in essence to Rajasthan’s diversion of the wet season rains by the johads into underground aquifers rather than letting the water run to waste.

Its message is that solutions need to be low-tech, cheap and achievable by local people acting together democratically to decide what is best for the community. Often this involves resisting local government and big business in their attempts to exploit and profit from the scarce water   frequently the cause of the original damage to the river.

The Alliance says two lessons from Rajasthan translate to other locations and across cultures: first, the physical return of water in a controlled way to an arid environment is possible using low-tech, cheap, accessible solutions.

Second, it says, the guardianship of a natural resource can be achieved effectively by using a communal parliament where all interests are represented equally and fair decisions are taken. – Climate News Network

* * * * * * *

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

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

Indian villagers who brought dried-up rivers back to life then had to fight a legal battle to use their water.

LONDON, 7 August, 2020 – Drought and dried-up rivers can spell catastrophe for rural communities that rely on their crops for survival. But villagers in India have shown that both threats can be reversed and livelihoods restored – with the backing of the law.

Having succeeded in restoring their rivers’ flow, the villagers faced another battle with their local government and vested interests which wanted to take over the new water supply for their own use. So they went to court, formed their own “water parliament”, and wrested back control.

The story began back in 1985 in the parched lands of Rajasthan in north-west India, when villagers were suffering acutely because the rivers they relied on to water their crops were running dry. They resorted to building johads, traditional hand-dug earth dams, which capture water in the rainy season so that it can soak into the earth and be retained instead of flooding away uselessly.

Often called natural flood management, this approach mimics the natural process of rivers which become blocked by debris and trees – with the beneficial results seen in the complex ecosystems created by beavers, which build their own dams and thereby prevent flooding downstream while also storing water for the dry season.

The first dam was built at the original source of the Arvari river, which for the first 45 kilometres of its length had stopped flowing at all. It took 375 earth dams before the Arvari started to flow again, and 10 years before it became a perennial river once more.

“The unsustainable use of water in modern agriculture and the demands made on aquifers by conurbations is already at breaking point in many places around the globe”

Success was infectious. Altogether, over those 10 years, the residents of 1,000 villages built more than 8,600 johads and other structures to collect water for use in the dry seasons. Remarkably, five rivers – the Arvari, Ruparel, Sarsa, Bhagani and Jahajwali – began to flow again, their valleys turning green with crops.

The rivers gained in value again. So the government of Rajasthan, seeing an opportunity to make money, claimed ownership, even awarding fishing licences to contractors, who were stopped by furious local people.

Fortunately the courts sided with the protestors and handed control of the river to them after 72 villages formed what they called the Arvari River Parliament to administer the river and allot rights to water resources in a fair manner.

They were lucky: the Indian constitution allows local people to get financial and legal support in cases against perceived injustices. This meant they had access to justice which they could not otherwise have afforded. The system favours local democracy where it can be shown to work.

Over-exploitation

The Rapid Transition Alliance (RTA) is a UK-based organisation which argues that humankind must undertake “widespread behaviour change to sustainable lifestyles … to live within planetary ecological boundaries and to limit global warming to below 1.5°C” (the more stringent limit set by the 2015 Paris Agreement on climate change).

The story of the success of the earth dams is told by the RTA as part of its series publicising global examples of how projects and communities can combat the environmental destruction caused by the effects of climate heating.

The drying-up of water resources, combined with climate change, is one of the key problems of poor river management in many parts of the world. Climates vary markedly, but on rivers in Africa, Europe and the US vital water resources are also drying up, often through over-exploitation as well as drought.

The Alliance says: “The unsustainable use of water in modern agriculture and the demands made on aquifers by conurbations is already at breaking point in many places around the globe. Climate change is exacerbating this with higher temperatures in already dry places.”

Resisting usurpers

It cites a range of schemes used to tackle the problem, similar in essence to Rajasthan’s diversion of the wet season rains by the johads into underground aquifers rather than letting the water run to waste.

Its message is that solutions need to be low-tech, cheap and achievable by local people acting together democratically to decide what is best for the community. Often this involves resisting local government and big business in their attempts to exploit and profit from the scarce water   frequently the cause of the original damage to the river.

The Alliance says two lessons from Rajasthan translate to other locations and across cultures: first, the physical return of water in a controlled way to an arid environment is possible using low-tech, cheap, accessible solutions.

Second, it says, the guardianship of a natural resource can be achieved effectively by using a communal parliament where all interests are represented equally and fair decisions are taken. – Climate News Network

* * * * * * *

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

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

250 million coastal dwellers will face rising floods

Once again, researchers confirm that coastal dwellers can expect worse floods, more often and more expensively.

LONDON, 6 August, 2020 – In the next 80 years flooding around the planet’s land masses is likely to rise by almost 50%, endangering many millions of coastal dwellers.

If humans go on burning ever greater volumes of fossil fuels, while destroying ever more natural forest, then another 77 million people could be at risk of flooding, a rise of 52%.

And these floods – increasingly frequent and extending over greater areas – will put at risk cities, homes, resorts and industries valued at more than $14 trillion (£10.7tn).

This sum alone is worth 20% of global gross domestic product, the economist’s preferred indicator of economic health and wealth, according to a new study in the journal Scientific Reports.

The researchers built their argument on historic data from 681 tide-gauge stations around the world to model the growing hazard at 10,000 coastal locations.

“Compared with now, what we see as a one-in-100-year extreme flood event will be ten times more frequent because of climate change”

They conclude that the land area exposed to extreme flood will increase by more than 250,000 sq kms – an increase of 48% – to 800,000 sq kms, a threat to 252 million people.

“A warming climate is driving sea level rise because water expands as it warms, and glaciers are melting. Climate change is also increasing the frequency of extreme seas, which will further increase the risk of flooding,” said Ebru Kirezci of the University of Melbourne, Australia, who led the study.

“What the data and our model are saying is that compared with now, what we see as a one-in-100-year extreme flood event will be ten times more frequent because of climate change.”

None of this should come as a surprise to civic authorities, governments, hydraulic engineers and oceanographers: researchers have been warning for years that coastal floods driven by global heating will end up costing colossal and seemingly ever increasing sums.

On a global scale, and on regional examination, the story remains the same, and wealthy and developed societies in Europe and the US face the same rising tide of hazard as the world’s poorest in the crowded coastal cities of Africa and Asia.

Estimate too low?

A mix of more extreme storms and storm surges, combined with ever higher sea levels, will sweep away the world’s beaches and turn millions of comfortable US citizens into climate refugees.

It is even possible that researchers have under-estimated the hazard, simply because satellite-based measurements may have misread precise land elevation: in some cases, too, coasts are sinking independently of sea level rise.

The latest study identifies a series of flood “hotspots” around the world. These include south-eastern China, Australia’s Northern Territory, Bangladesh, West Bengal and Gujarat in India, the US states of North Carolina, Virginia and Maryland, and north-west Europe including the UK, northern France and northern Germany. The new map of risks takes no account of existing flood defences, but highlights the levels of threat to come.

“This is critical research from a policy point of view, because it provides politicians with a credible estimate of the risks and costs we are facing, and a basis for taking action,” said Ian Young, an engineer at the University of Melbourne, and a co-author.

“This data should act as a wake-up call to inform policy at global and local government levels so that more flood defences can be built to safeguard coastal life and infrastructure.” – Climate News Network

Once again, researchers confirm that coastal dwellers can expect worse floods, more often and more expensively.

LONDON, 6 August, 2020 – In the next 80 years flooding around the planet’s land masses is likely to rise by almost 50%, endangering many millions of coastal dwellers.

If humans go on burning ever greater volumes of fossil fuels, while destroying ever more natural forest, then another 77 million people could be at risk of flooding, a rise of 52%.

And these floods – increasingly frequent and extending over greater areas – will put at risk cities, homes, resorts and industries valued at more than $14 trillion (£10.7tn).

This sum alone is worth 20% of global gross domestic product, the economist’s preferred indicator of economic health and wealth, according to a new study in the journal Scientific Reports.

The researchers built their argument on historic data from 681 tide-gauge stations around the world to model the growing hazard at 10,000 coastal locations.

“Compared with now, what we see as a one-in-100-year extreme flood event will be ten times more frequent because of climate change”

They conclude that the land area exposed to extreme flood will increase by more than 250,000 sq kms – an increase of 48% – to 800,000 sq kms, a threat to 252 million people.

“A warming climate is driving sea level rise because water expands as it warms, and glaciers are melting. Climate change is also increasing the frequency of extreme seas, which will further increase the risk of flooding,” said Ebru Kirezci of the University of Melbourne, Australia, who led the study.

“What the data and our model are saying is that compared with now, what we see as a one-in-100-year extreme flood event will be ten times more frequent because of climate change.”

None of this should come as a surprise to civic authorities, governments, hydraulic engineers and oceanographers: researchers have been warning for years that coastal floods driven by global heating will end up costing colossal and seemingly ever increasing sums.

On a global scale, and on regional examination, the story remains the same, and wealthy and developed societies in Europe and the US face the same rising tide of hazard as the world’s poorest in the crowded coastal cities of Africa and Asia.

Estimate too low?

A mix of more extreme storms and storm surges, combined with ever higher sea levels, will sweep away the world’s beaches and turn millions of comfortable US citizens into climate refugees.

It is even possible that researchers have under-estimated the hazard, simply because satellite-based measurements may have misread precise land elevation: in some cases, too, coasts are sinking independently of sea level rise.

The latest study identifies a series of flood “hotspots” around the world. These include south-eastern China, Australia’s Northern Territory, Bangladesh, West Bengal and Gujarat in India, the US states of North Carolina, Virginia and Maryland, and north-west Europe including the UK, northern France and northern Germany. The new map of risks takes no account of existing flood defences, but highlights the levels of threat to come.

“This is critical research from a policy point of view, because it provides politicians with a credible estimate of the risks and costs we are facing, and a basis for taking action,” said Ian Young, an engineer at the University of Melbourne, and a co-author.

“This data should act as a wake-up call to inform policy at global and local government levels so that more flood defences can be built to safeguard coastal life and infrastructure.” – Climate News Network