Reuters
Tue 24 September 2024
Flooding Danube in Hungary
WARSAW (Reuters) - Climate change has made downpours like the one that caused devastating floods in central Europe this month twice as likely to occur, a report said on Wednesday, as its scientific authors urged policymakers to act to stop global warming.
The worst flooding to hit central Europe in at least two decades has left 24 people dead, with towns strewn with mud and debris, buildings damaged, bridges collapsed and authorities left with a bill for repairs that runs into billions of dollars.
The report from World Weather Attribution, an international group of scientists that studies the effects of climate change on extreme weather events, found that the four days of rainfall brought by Storm Boris were the heaviest ever recorded in central Europe.
It said that climate change had made such downpours at least twice as likely and 7% heavier.
"Yet again, these floods highlight the devastating results of fossil fuel-driven warming," Joyce Kimutai, a researcher at Imperial College London's Grantham Institute and co-author of the study, said in a statement.
"Until oil, gas and coal are replaced with renewable energy, storms like Boris will unleash even heavier rainfall, driving economy-crippling floods."
The report said that while the combination of weather patterns that caused the storm - including cold air moving over the Alps and very warm air over the Mediterranean and the Black Seas - was unusual, climate change made such storms more intense and more likely.
According to the report, such a storm is expected to occur on average about once every 100 to 300 years in today's climate with 1.3 degrees Celsius of warming from pre-industrial levels.
However, it said that such storms will result in at least 5% more rain and occur about 50% more frequently than now if warming from pre-industrial levels reaches 2 C, which is expected to happen in the 2050s.
(Reporting by Alan Charlish; Editing by Ros Russell)
Deadly flooding in Central Europe made twice as likely by climate change
SUMAN NAISHADHAM
Updated Tue 24 September 2024
WASHINGTON (AP) — Human-caused climate change doubled the likelihood and intensified the heavy rains that led to devastating flooding in Central Europe earlier this month, a new flash study found.
Torrential rain in mid-September from Storm Boris pummeled a large part of central Europe, including Romania, Poland, Czechia, Austria, Hungary, Slovakia and Germany, and caused widespread damage. The floods killed 24 people, damaged bridges, submerged cars, left towns without power and in need of significant infrastructure repairs.
The severe four-day rainfall was “by far” the heaviest ever recorded in Central Europe and twice as likely because of warming from the burning of coal, oil and natural gas, World Weather Attribution, a collection of scientists that run rapid climate attribution studies, said Wednesday from Europe. Climate change also made the rains between 7% and 20% more intense, the study found.
“Yet again, these floods highlight the devastating results of fossil fuel-driven warming," said Joyce Kimutai, the study's lead author and a climate researcher at Imperial College, London.
To test the influence of human-caused climate change, the team of scientists analyzed weather data and used climate models to compare how such events have changed since cooler preindustrial times to today. Such models simulate a world without the current 1.3 degrees Celsius (2.3 degrees Fahrenheit) of global warming since preindustrial times, and see how likely a rainfall event that severe would be in such a world.
The study analyzed four-day rainfall events, focusing on the countries that felt severe impacts.
Though the rapid study hasn't been peer-reviewed, it follows scientifically accepted techniques.
“In any climate, you would expect to occasionally see records broken," said Friederike Otto, an Imperial College, London, climate scientist who coordinates the attribution study team. But, “to see records being broken by such large margins, that is really the fingerprint of climate change. And that is only something that we see in a warming world.”
Some of the most severe impacts were felt in the Polish-Czech border region and Austria, mainly in urban areas along major rivers. The study noted that the death toll from this month's flooding was considerably lower than during catastrophic floods in the region in 1997 and 2002. Still, infrastructure and emergency management systems were overwhelmed in many cases and will require billions of euros to fix.
Last week, European Union chief Ursula von der Leyen pledged billions of euros in aid for countries that suffered damage to infrastructure and housing from the floods.
The World Weather Attribution study also warned that in a world with even more warming — specifically 2 degrees Celsius (3.6 degrees Fahrenheit) of warming since preindustrial times, the likelihood of ferocious four-day storms would grow by 50% compared to current levels. Such storms would grow in intensity, too, the authors found.
The heavy rainfall across Central Europe was caused by what's known as a “Vb depression” that forms when cold polar air flows from the north over the Alps and meets warm air from Southern Europe. The study's authors found no observable change in the number of similar Vb depressions since the 1950s.
The World Weather Attribution group launched in 2015 largely due to frustration that it took so long to determine whether climate change was behind an extreme weather event. Studies like theirs, within attribution science, use real-world weather observations and computer modeling to determine the likelihood of a particular happening before and after climate change, and whether global warming affected its intensity.
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Global heating ‘doubled’ chance of extreme rain in Europe in September
Ajit Niranjan Europe environment correspondent
THE GUARDIAN
Tue 24 September 2024
Residents wade through flood water after the Nysa Klodzka River flooded the town of Lewin Brzeski in south-west Poland on 19 September.Photograph: Beata Zawrzel/NurPhoto/Rex/Shutterstock
Planet-heating pollution doubled the chance of the extreme levels of rain that hammered central Europe in September, a study has found.
Researchers found global heating aggravated the four days of heavy rainfall that led to deadly floods in countries from Austria to Romania.
The rains were made at least 7% stronger by climate change, World Weather Attribution (WWA) found, which led to towns being hit with volumes of water that would have been half as likely to occur if humans had not heated the planet.
“The trend is clear,” said Bogdan Chojnicki, a climate scientist at Poznań University of Life Sciences, and co-author of the study. “If humans keep filling the atmosphere with fossil fuel emissions, the situation will be more severe.”
Storm Boris stalled over central Europe in mid-September and unleashed record-breaking amounts of rain upon Austria, the Czech Republic, Hungary, Poland, Romania and Slovakia. The heavy rains turned calm streams into wild rivers, triggering floods that wrecked homes and killed two dozen people.
The researchers said measures to adapt had lowered the death toll compared with similar floods that hit the region in 1997 and 2002. They called for better flood defences, warning systems and disaster-response plans, and warned against continuing to rebuild in flood-prone regions.
“These floods indicate just how costly climate change is becoming,” said Maja Vahlberg, technical adviser at the Red Cross Red Crescent Climate Centre, and co-author of the study. “Even with days of preparation, flood waters still devastated towns, destroyed thousands of homes and saw the European Union pledge €10bn in aid.”
Rapid attribution studies, which use established methods but are published before going through lengthy peer-review processes, examine how human influence affects extreme weather in the immediate aftermath of a disaster.
The scientists compared the rainfall recorded in central Europe over four days in September with amounts simulated for a world that is 1.3C cooler – the level of warming caused to date by burning fossil fuels and destroying nature. They attributed a “doubling in likelihood and a 7% increase in intensity” to human influence.
But the results are “conservative”, the scientists wrote, because the models do not explicitly model convection and so may underestimate rainfall. “We emphasise that the direction of change is very clear, but the rate is not.”
Related: Storm Boris batters central Europe – in pictures
Physicists have shown that every degree celsius of warming allows the air to hold 7% more moisture, but whether it does so depends on the availability of water. The rains in central Europe were unleashed when cold air from the Arctic met warm, wet air from the Mediterranean and the Black Sea.
Warmer seas enhance the rainy part of the hydrological cycle, though the trend on parts of the land is towards drier conditions, said Miroslav Trnka, a climate scientist at the Global Change Research Institute, who was not involved in the study. When the conditions were right, he said, “you can have floods on steroids”.
Trnka compared the factors that result in extreme rainfall to playing the lottery. The increase in risk from global heating, he said, was like buying more lottery tickets, doing so over a longer period of time, and changing the rules so more combinations of numbers result in a win.
“If you bet long enough, you have a higher chance of a jackpot,” said Trnka.
The study found heavier four-day rainfall events would hit if the world heats 2C above preindustrial levels, with a further increase from today of about 5% in rainfall intensity and 50% in likelihood.
Other factors could increase this even more, such as the waviness of the jet stream, which some scientists suspect is increasingly trapping weather systems in one place as a result of global heating. A study published in Nature Scientific Reports on Monday projected that such blocking systems would increase under medium- and worst-case emissions scenarios.
Hayley Fowler, a climate scientist at Newcastle University, who was not involved in the study, said: “These large storms, cut off from the jet stream, are able to stagnate in one place and produce huge amounts of rainfall, fuelled by increased moisture and energy from oceans that are record-shatteringly hot.”
“These ‘blocked’ slow-moving storms are becoming more frequent and are projected to increase further with additional warming,” she added. “The question is not whether we need to adapt for more of these types of storm but can we.”
WWA described the week following Storm Boris as “hyperactive” because 12 disasters around the world triggered its criteria for analysis, more than in any week in the organisation’s history.
The study did not try to work out how much global heating had increased the destruction wreaked by the rains but the researchers said even minor increases in rainfall disproportionately increased damages.
“Almost everywhere in the world it is the case that a small increase in the rainfall leads to a similar order-of-magnitude increase in flooding,” said Friederike Otto, a climate scientist at Imperial College London’s Grantham Institute and co-author of the study. “But that leads to a much larger increase in the damages.”
Tue 24 September 2024
Residents wade through flood water after the Nysa Klodzka River flooded the town of Lewin Brzeski in south-west Poland on 19 September.Photograph: Beata Zawrzel/NurPhoto/Rex/Shutterstock
Planet-heating pollution doubled the chance of the extreme levels of rain that hammered central Europe in September, a study has found.
Researchers found global heating aggravated the four days of heavy rainfall that led to deadly floods in countries from Austria to Romania.
The rains were made at least 7% stronger by climate change, World Weather Attribution (WWA) found, which led to towns being hit with volumes of water that would have been half as likely to occur if humans had not heated the planet.
“The trend is clear,” said Bogdan Chojnicki, a climate scientist at Poznań University of Life Sciences, and co-author of the study. “If humans keep filling the atmosphere with fossil fuel emissions, the situation will be more severe.”
Storm Boris stalled over central Europe in mid-September and unleashed record-breaking amounts of rain upon Austria, the Czech Republic, Hungary, Poland, Romania and Slovakia. The heavy rains turned calm streams into wild rivers, triggering floods that wrecked homes and killed two dozen people.
The researchers said measures to adapt had lowered the death toll compared with similar floods that hit the region in 1997 and 2002. They called for better flood defences, warning systems and disaster-response plans, and warned against continuing to rebuild in flood-prone regions.
“These floods indicate just how costly climate change is becoming,” said Maja Vahlberg, technical adviser at the Red Cross Red Crescent Climate Centre, and co-author of the study. “Even with days of preparation, flood waters still devastated towns, destroyed thousands of homes and saw the European Union pledge €10bn in aid.”
Rapid attribution studies, which use established methods but are published before going through lengthy peer-review processes, examine how human influence affects extreme weather in the immediate aftermath of a disaster.
The scientists compared the rainfall recorded in central Europe over four days in September with amounts simulated for a world that is 1.3C cooler – the level of warming caused to date by burning fossil fuels and destroying nature. They attributed a “doubling in likelihood and a 7% increase in intensity” to human influence.
But the results are “conservative”, the scientists wrote, because the models do not explicitly model convection and so may underestimate rainfall. “We emphasise that the direction of change is very clear, but the rate is not.”
Related: Storm Boris batters central Europe – in pictures
Physicists have shown that every degree celsius of warming allows the air to hold 7% more moisture, but whether it does so depends on the availability of water. The rains in central Europe were unleashed when cold air from the Arctic met warm, wet air from the Mediterranean and the Black Sea.
Warmer seas enhance the rainy part of the hydrological cycle, though the trend on parts of the land is towards drier conditions, said Miroslav Trnka, a climate scientist at the Global Change Research Institute, who was not involved in the study. When the conditions were right, he said, “you can have floods on steroids”.
Trnka compared the factors that result in extreme rainfall to playing the lottery. The increase in risk from global heating, he said, was like buying more lottery tickets, doing so over a longer period of time, and changing the rules so more combinations of numbers result in a win.
“If you bet long enough, you have a higher chance of a jackpot,” said Trnka.
The study found heavier four-day rainfall events would hit if the world heats 2C above preindustrial levels, with a further increase from today of about 5% in rainfall intensity and 50% in likelihood.
Other factors could increase this even more, such as the waviness of the jet stream, which some scientists suspect is increasingly trapping weather systems in one place as a result of global heating. A study published in Nature Scientific Reports on Monday projected that such blocking systems would increase under medium- and worst-case emissions scenarios.
Hayley Fowler, a climate scientist at Newcastle University, who was not involved in the study, said: “These large storms, cut off from the jet stream, are able to stagnate in one place and produce huge amounts of rainfall, fuelled by increased moisture and energy from oceans that are record-shatteringly hot.”
“These ‘blocked’ slow-moving storms are becoming more frequent and are projected to increase further with additional warming,” she added. “The question is not whether we need to adapt for more of these types of storm but can we.”
WWA described the week following Storm Boris as “hyperactive” because 12 disasters around the world triggered its criteria for analysis, more than in any week in the organisation’s history.
The study did not try to work out how much global heating had increased the destruction wreaked by the rains but the researchers said even minor increases in rainfall disproportionately increased damages.
“Almost everywhere in the world it is the case that a small increase in the rainfall leads to a similar order-of-magnitude increase in flooding,” said Friederike Otto, a climate scientist at Imperial College London’s Grantham Institute and co-author of the study. “But that leads to a much larger increase in the damages.”
8 / 8
Climate Central Europe Floods
FILE - Firefighters walk through a flooded road of Jesenik, Czech Republic, Sept. 15, 2024. (AP Photo/Petr David Josek, File)
ASSOCIATED PRESS
‘We’re getting rid of everything’: floods destroy homes and lives in Czech Republic
Ajit Niranjan
Tue 24 September 2024
A resident and his dog are evacuated from his flooded house in Jesenik. Photograph: Anadolu/Getty Images
Jarmila Šišmová did not know what to expect when rain began to pound the small town of Litovel in the Czech Republic, and she was not prepared for the nightmare that would await her once it stopped.
The authorities told Šišmová to leave her home, so she took her children to their grandmother to wait out the storm. As the water level rose, a neighbour – one of the few on her street who stayed behind – checked the front of the house and saw the sandbags holding firm. But from the back, Šišmová would soon find out, the flood had burst into the building, drenching her belongings in dirty brown water.
“It was devastating for me,” said Šišmová, a sales manager and single mother of three, gesturing to a skip full of furniture, clothes and toys. “We’re getting rid of everything.”
Stories like Šišmová’s are being echoed around the world. The Czech Republic sat at the centre of a storm that has killed two dozen people across central Europe and prompted the EU to promise €10bn in aid to flood-stricken countries. It came as torrential rains swept through parts of Africa and Asia, triggering inundations that have killed more than 1,000 people. The UK was also hit by downpours on Monday, with more than a month’s worth of rain in 24 hours in some parts of the country.
The extreme levels of rain in Europe were made twice as likely by planet-heating pollution, a rapid attribution study found on Wednesday, and 7% stronger.
Miroslav Trnka, a climate scientist from the Global Change Research Institute, said a 7% average increase may not sound like a lot but can be enough to render a dam useless.
“It’s a binary problem” he said. “It’s not like flood defences partly work, they either don’t work or fully work, and there is a relatively small space in between.”
In towns along the Czech Republic’s border with Poland, where the floods hit hardest, residents described how the supercharged torrents of water tore their lives apart.Interactive
In Krnov, where three people died, the city library said it lost more than 20,000 books to the flood waters and only had enough time to save the most important volumes from its collection. Jakub Mruz, the director of the library, said the loss was “negligible” compared with what other people had experienced, but “it is sad and painful for anyone who loves books to see something like this.”
In Jesenik, where one person died, nearly 500mm of rain fell in five days, aggravated by wind patterns in the mountains and the bare slopes on which bark beetles had ravaged spongy spruce forests. The sewage system in the city failed and the flood smeared a layer of toxic mud across its streets.
“Now it’s dried up, people are breathing the dust and getting diarrhoea,” said Adriana Černá, an executive board member of People in Need, a humanitarian group working with the rescue services. “From day to day the situation is getting better. But there’s a big mess.”
Scientists have shown that warm air can hold more moisture – about 7% for each 1C increase in temperature – which allows for more violent rainfall if enough water is available.
Mountain towns such as Jesenik are particularly vulnerable. A study last year found a 15% increase in extreme rainfall per degree of warming at high altitude – double that expected by the physical relationship between temperature and moisture content.
In Litovel, further south, Petr Švancr, whose guesthouse was inundated, estimated the damage would come to 2m Czech crowns (£66,000). “The hotel’s closed, the restaurant is closed, everything is closed. My life has closed – it’s finished.”
Šišmová, who moved to Litovel 10 years ago, said she had cried in recent days because she no longer knew if she wanted to live there.
“If you have to start from zero, you can start anywhere,” she said. “I don’t know if I want to be part of another flood in a few years.”
In 1997, central Europe was devastated by what was dubbed the “flood of the century” – a disaster that killed 56 people in Poland and 50 in the Czech Republic. Since then, investments in systems to predict rain, warn communities and manage water have lowered the death toll from floods even when rains have hit hard.
But Michal Žák, a meteorologist at Czech Television, said although more rain fell over the total period in 1997 than in 2024, the one-day maximum amounts were greater in the latest disaster. “The extremity of the precipitation in the models was quite impressive,” said Žák, who had been alarmed by the projections. “I was not so sure it would really happen, but finally it did.”
Volunteers have been arriving to help clean up, with authorities asking that they register with aid groups before arrival. Václav Kvapil, a carpenter who runs a guesthouse in a village near Jesenik with his wife, said they hosted 80 volunteers for free after prospective visitors cancelled their reservations.
“We were surprised how many people wanted to come,” he said. “In the end, we were forced to refuse some people because the house was so full.”
Ajit Niranjan
Tue 24 September 2024
A resident and his dog are evacuated from his flooded house in Jesenik. Photograph: Anadolu/Getty Images
Jarmila Šišmová did not know what to expect when rain began to pound the small town of Litovel in the Czech Republic, and she was not prepared for the nightmare that would await her once it stopped.
The authorities told Šišmová to leave her home, so she took her children to their grandmother to wait out the storm. As the water level rose, a neighbour – one of the few on her street who stayed behind – checked the front of the house and saw the sandbags holding firm. But from the back, Šišmová would soon find out, the flood had burst into the building, drenching her belongings in dirty brown water.
“It was devastating for me,” said Šišmová, a sales manager and single mother of three, gesturing to a skip full of furniture, clothes and toys. “We’re getting rid of everything.”
Stories like Šišmová’s are being echoed around the world. The Czech Republic sat at the centre of a storm that has killed two dozen people across central Europe and prompted the EU to promise €10bn in aid to flood-stricken countries. It came as torrential rains swept through parts of Africa and Asia, triggering inundations that have killed more than 1,000 people. The UK was also hit by downpours on Monday, with more than a month’s worth of rain in 24 hours in some parts of the country.
The extreme levels of rain in Europe were made twice as likely by planet-heating pollution, a rapid attribution study found on Wednesday, and 7% stronger.
Miroslav Trnka, a climate scientist from the Global Change Research Institute, said a 7% average increase may not sound like a lot but can be enough to render a dam useless.
“It’s a binary problem” he said. “It’s not like flood defences partly work, they either don’t work or fully work, and there is a relatively small space in between.”
In towns along the Czech Republic’s border with Poland, where the floods hit hardest, residents described how the supercharged torrents of water tore their lives apart.Interactive
In Krnov, where three people died, the city library said it lost more than 20,000 books to the flood waters and only had enough time to save the most important volumes from its collection. Jakub Mruz, the director of the library, said the loss was “negligible” compared with what other people had experienced, but “it is sad and painful for anyone who loves books to see something like this.”
In Jesenik, where one person died, nearly 500mm of rain fell in five days, aggravated by wind patterns in the mountains and the bare slopes on which bark beetles had ravaged spongy spruce forests. The sewage system in the city failed and the flood smeared a layer of toxic mud across its streets.
“Now it’s dried up, people are breathing the dust and getting diarrhoea,” said Adriana Černá, an executive board member of People in Need, a humanitarian group working with the rescue services. “From day to day the situation is getting better. But there’s a big mess.”
Scientists have shown that warm air can hold more moisture – about 7% for each 1C increase in temperature – which allows for more violent rainfall if enough water is available.
Mountain towns such as Jesenik are particularly vulnerable. A study last year found a 15% increase in extreme rainfall per degree of warming at high altitude – double that expected by the physical relationship between temperature and moisture content.
In Litovel, further south, Petr Švancr, whose guesthouse was inundated, estimated the damage would come to 2m Czech crowns (£66,000). “The hotel’s closed, the restaurant is closed, everything is closed. My life has closed – it’s finished.”
Šišmová, who moved to Litovel 10 years ago, said she had cried in recent days because she no longer knew if she wanted to live there.
“If you have to start from zero, you can start anywhere,” she said. “I don’t know if I want to be part of another flood in a few years.”
In 1997, central Europe was devastated by what was dubbed the “flood of the century” – a disaster that killed 56 people in Poland and 50 in the Czech Republic. Since then, investments in systems to predict rain, warn communities and manage water have lowered the death toll from floods even when rains have hit hard.
But Michal Žák, a meteorologist at Czech Television, said although more rain fell over the total period in 1997 than in 2024, the one-day maximum amounts were greater in the latest disaster. “The extremity of the precipitation in the models was quite impressive,” said Žák, who had been alarmed by the projections. “I was not so sure it would really happen, but finally it did.”
Volunteers have been arriving to help clean up, with authorities asking that they register with aid groups before arrival. Václav Kvapil, a carpenter who runs a guesthouse in a village near Jesenik with his wife, said they hosted 80 volunteers for free after prospective visitors cancelled their reservations.
“We were surprised how many people wanted to come,” he said. “In the end, we were forced to refuse some people because the house was so full.”
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