31/07/2018

'Unique And Alarming': Engineers To Be Tested As Rain Events Intensify

FairfaxPeter Hannam

Australia's rainfall events are already becoming more intense with climate change, raising the risks of flashflooding and potentially exceeding the nation's engineering codes, a new study finds.
While it's long been understood the atmosphere holds about 6.5 per cent more moisture per degree of warming, climate models have largely not captured the impact on individual storms, said Seth Westra, an associate professor at the University of Adelaide’s engineering school.
Intense rain events - an extreme example of which hit Toowoomba in Queensland in 2011 - are becoming more common, researchers say. Photo: Troy Campbell

"It's much more, two or three times the rate of that simple rule of thumb," said Professor Westra, who is one of the authors of the paper appearing in Nature Climate Change on Tuesday. "It's a really unique and alarming aspect of our conclusions."
The study examined rainfall records across Australia from 1966 to 2013 and identified an increase in the intensity of short-duration rain events "well outside the natural year-to-year variability you'd expect", he said. "In fact, they are more severe than climate models have been suggesting."
"The sorts of rates that engineers have been using [for these events] are lower than the historical changes that we're observing in this study," Professor Westra said, adding that engineering codes may need to be updated to recognise "more radical rainfall" events in the future.
Climate change models have been better at picking up heatwaves amid the rise in average temperatures but they struggled more with rainfall. One reason is that individual thunderstorms can account for the jump in rainfall and they can be harder to model than temperature spikes.
Todd Lane, deputy director of the ARC Centre of Excellence for Climate Extremes, said the report is the first one to identify the trend in Australia after it had been discerned in Britain and elsewhere.
These rainfall bursts "create your flashflooding events and really challenge the resilience of your infrastructure", said Dr Lane, who is also an associate professor at Melbourne University. "The most intense rainfall events are going to increase at a rate much faster than you expect."
While discussion about extreme rain may seem at odds with the current drought across much of eastern Australia, "the reality is that can happen one after the other" in this country, as history has shown, Professor Westra said.
Strains on drainage and other infrastructure are also being made worse by the paving of more of our cities, adding to the impervious surfaces that facilitate the rapid build-up of water, Professor Lane said.

Links

Current Heat Waves Are Linked To Climate Change, Scientists Confirm

Deutsche Welle - Katharina Wecker

Climate change has made the extremely high temperatures in Europe more than twice as likely to occur, a new analysis has revealed. How do scientists calculate the link between extreme weather events and climate change?

Record-breaking temperatures of up to 39 degrees Celcius (102.2 degrees Fahrenheit) in Germany; out-of-control wildfires in Sweden and other typically cool northerly regions; and a toxic algae outbreak in the warmer than usual Baltic Sea in Poland — Europe is sweltering in the current heat wave.
With the extreme high temperatures continuing in most parts of Europe, people are asking: Is climate change to blame?
Scientists say yes.
"Climate change has generally increased the odds of the current heat wave more than two-fold," said Geert Jan van Oldenborgh, a researcher at the Royal Netherlands Meteorological Institute.
He is part of World Weather Attribution (WWA), a network of scientists in six institutions established to provide near-real-time analysis of possible links between climate change and extreme weather events.
A WWA team has analyzed the current heat wave in northern Europe and presented preliminary results on Friday.
To stay cool in record-high temperatures, you can follow the example of this little boy: play at a fountain
How do scientists connect specific weather events to climate change?
Pinning down blame for complex weather events isn't straightforward, due to the numerous variables involved, from water temperature to air pressure.
But thanks to state-of-the-art climate models, scientists can now calculate the likelihood of individual extreme weather events having happened due to climate change.
Like how epidemiologists link smoking to cancer, climate scientists work with statistical probability.
"Smoking is never the only reason — but it increases the likelihood to develop cancer," Friederike Otto, researcher at the Oxford University's Environmental Change Institute and member of the WWA, told DW.
To determine the likelihood that an individual extreme weather event is caused by climate change, scientists estimate what the probability of a particular extreme event would be in the climate of today, versus in the climate of a world free of human-caused greenhouse gas emissions.
We've already warmed the globe by about 1 degree Celsius, compared to pre-industrial times.
By comparing the results of these two scenarios, scientists can attribute any differences in probability of the extreme event to human-caused climate change.
With this method, the WWA network has already shown that climate change made Hurricane Harvey in 2017 three times as likely to happen, the Lucifer heat wave that swept southern Europe in 2017 four times as likely to happen, and did not change the likelihood of the 2014 Sao Paolo drought taking place.
The banks of the river Rhine in Düsseldorf have cracked due to dryness
How did they calculate the probability of climate change causing the current heat wave?
The WWA researchers compared the currently high temperatures with historical records at seven weather stations in northern Europe — two in Finland and one each in Denmark, the Irish Republic, the Netherlands, Norway and Sweden.
The weather stations were selected for practical reasons. Current temperature data could be accessed in real time, and all of them had digitalized records extending back to the early 1900s.
For each year in the historical record, the scientists looked at the hottest consecutive three days. For 2018, they took the hottest three days of the year so far.
They then fed their the datainto  climate models, and compared the results of the world today with the world from the past when greenhouse gas emissions were much lower.
In the case of Copenhagen, the group found that a heat wave like the current one occurs every seven years in our current world. But in a world without manmade climate change, such a heat wave as this one occurs only every 35 years.
Even dogs seek refreshment during the current heat wave
"We can thus say climate change increased the likelihood of the event to occur by a factor of ten [in the case of Copenhagen]," Otto told DW.
Compiling all the results from the seven analyzed weather stations across Europe, the scientists found that the probability of such heat waves is overall twice as probable today than if human activities had not altered the climate.
The results are not yet peer-reviewed, because the WWA scientists are aiming to provide a quick analysis of current extreme weather events since public interest is high. They do plan to publish the results formally in a scientific journal, as they have done with previous analyses.

Why is it important to attribute specific extreme weather events to climate change?
Climate change is an abstract topic with abstract measures, for example the increase of the average global temperature on Earth.
But people don't experience average temperatures; they experience heavy rainfall (including flooding), heat waves, severe storms and droughts, researchers point out.
"It's very important to provide illustrations of the effects of climate change," Robert Vautard, a senior scientist with France's Laboratory for Climate and Environment Sciences, told DW.
Only when we undestand what climate change looks like can we can prepare for it, he thinks.
After the deadly heat wave in 2003, which resulted in the death of 15,000 people in France alone, the French government created an emergency plan to deal with future heat-related health problems.
But experts believes their plan might already be outdated.
"Our infrastructure and healthcare plans are based on heat waves and rainfall we have witnessed in the past. But we have to realize that the climate today is not the same it used to be, and it will be very different in the future," Vautard added.
Lawmakers in the United Kingdom, where unusual high temperatures of more than 30 degrees Celsius were recorded last week, face a similar fear.
They have warned that premature deaths from heat waves could triple by 2050, and call upon the government to develop a strategy to protect the health of the public.

Will we see more extreme weather events in the future?
Climate scientists almost universally agree: Yes.
"Extreme heat events like this one will become more frequent and more intense as the globe continues to warm," Andrew King, a researcher at the ARC Centre of Excellence for Climate Extremes at the University of Melbourne, told DW.
"We know that heat waves and hot summers, like the infamous hot summer of 2003 in Europe, will very likely occur in most years, even under only 2 degrees Celsius of global warming," he added.
The Paris Climate Agreement seeks to limit global warming between 1.5 and 2 degrees Celsius but on our current track,we are moving towards 3 degrees warming.
The climate is not just getting hotter — it's getting less predictable.
Variability of extreme weather events will increase, confirmed climate scientist Otto. While we may one year see heat waves, the next year we could experience extreme rainfall. And the picture can look very different from location to location.
"The dangerous thing about climate change is that what we are not adapted to the changes," said Otto.
Beyond the urgent current need to limit global warming to under 2 degrees Celsius, learning to adapt quickly to extreme weather events will be a great challenge for the future.
Spray fountains keep Parisians cool
Until storms broke the intense heat on Friday evening, Parisians made use of the city's recreational facilities to keep cool, including water fountains around the Eiffel Tower. Despite being 3,324 pages long, France's infamous labor code doesn't mention a specific temperature that would force companies to shut down. But staff can't be punished if they stop work over fears for their health.

Links

How Record Heat Wreaked Havoc On Four Continents

New York TimesSomini Sengupta* | Tiffany May* | Zia ur-Rehman*

We talked to people who found themselves on the front lines of climate change this year. Here are their stories.
Stephanie Davidson for The New York Times
Expect more. That’s the verdict of climate scientists to the record-high temperatures this spring and summer in vastly different climate zones.
The continental United States had its hottest month of May and the third-hottest month of June. Japan was walloped by record triple-digit temperatures, killing at least 86 people in what its meteorological agency bluntly called a “disaster.” And weather stations logged record-high temperatures on the edge of the Sahara and above the Arctic Circle.
Is it because of climate change? Scientists with the World Weather Attribution project concluded in a study released Friday that the likelihood of the heat wave currently baking Northern Europe is “more than two times higher today than if human activities had not altered climate.”
While attribution studies are not yet available for other record-heat episodes this year, scientists say there’s little doubt that the ratcheting up of global greenhouse gases makes heat waves more frequent and more intense.
Elena Manaenkova, deputy head of the World Meteorological Organization, said this year was “shaping up to be one of the hottest years on record” and that the extreme heat recorded so far was not surprising in light of climate change.
“This is not a future scenario,” she said. “It is happening now.”
What was it like to be in these really different places on these really hot days? We asked people. Here’s what we learned.

Stephanie Davidson for The New York Times




Ouargla, Algeria: 124°F on July 5
At 3 p.m. on the first Thursday of July, on the edge of the vast Sahara, the Algerian oil town of Ouargla recorded a high of 124 degrees Fahrenheit. Even for this hot country, it was a record, according to Algeria’s national meteorological service.
Abdelmalek Ibek Ag Sahli was at work in a petroleum plant on the outskirts of Ouargla that day. He and the rest of his crew had heard it would be hot. They had to be at work by 7 a.m., part of a regular 12-hour daily shift.
“We couldn’t keep up,” he recalled. “It was impossible to do the work. It was hell.”
By 11 a.m., he and his colleagues walked off the job.
But when they got back to the workers’ dorms, things weren’t much better. The power had gone out. There was no air conditioning, no fans. He dunked his blue cotton scarf in water, wrung it out, and wrapped it around his head. He drank water. He bathed 5 times. “At the end of the day I had a headache,” he said by phone. “I was tired.”
Ouargla’s older residents told him they’d never seen a day so hot.

Stephanie Davidson for The New York Times




Hong Kong: Over 91°F for 16 straight days
In this city of skyscrapers on the edge of the South China Sea, temperatures soared past 91 degrees Fahrenheit for 16 consecutive days in the second half of May.
Not since Hong Kong started keeping track in 1884 had a heat wave of that intensity lasted so long in May.
Swimming pools overflowed with people. Office air-conditioners purred. But from morning to night, some of the city’s most essential laborers went about their outdoor work, hauling goods, guarding construction sites, picking up trash.
One blistering morning, a 55-year-old woman named Lin gripped the hot metal handles of her handcart. She pushed it up a busy road, glancing over her shoulder for oncoming cars. She had fresh leafy greens to deliver to neighborhood restaurants in the morning, trash to haul in the evening. Some days, she had a headache. Other days, she vomited.
“It’s very hot and I sweat a lot,” said Lin, who would only give her first name before rushing off on her rounds. “But there’s no choice, I have to make a living.”
Poon Siu-sing, a 58 year-old trash collector, tossed garbage bags into a mounting pile. Sweat plastered the shirt onto his back. “I don’t feel anything,” he maintained. “I’m a robot used to the heat of the sun and rain.”

Stephanie Davidson for The New York Times




Nawabshah, Pakistan: 122°F on April 30
Nawabshah is in the heart of Pakistan’s cotton country. But no amount of cotton could provide comfort on the last day of April, when temperatures soared past 122 degrees Fahrenheit, or 50 degrees Celsius. Even by the standards of this blisteringly hot place, it was a record.
The streets were deserted that day, a local journalist named Zulfiqar Kaskheli said. Shops didn’t bother to open. Taxi drivers kept off the streets to avoid the blazing sun.
And so, Riaz Soomro had to scour his neighborhood for a cab that could take his ailing 62-year-old father to a hospital. It was Ramadan. The family was fasting. The father became dehydrated and passed out.
The government hospital was packed. In the hallways sat worn-out heatstroke victims like his father. Many of them had been working outdoors as day laborers, Mr. Soomro said.
Throughout the area, hospitals and clinics were swamped. There weren’t enough beds. There weren’t enough medical staff. The power failed repeatedly throughout the day, adding to the chaos.
“We tried our best to provide medical treatment,” said Raees Jamali, a paramedic in Daur, a village on the outskirts of Nawabshah. “But because of severity of the heat, there was unexpected rush and it was really difficult for us to deal with all patients.”
Every day that week, the high temperature in Nawabshah was no less than 113 degrees, according to AccuWeather.

Stephanie Davidson for The New York Times




Oslo: Over 86°F for 16 consecutive days
“Warning! We remind you about the total ban on fires and barbecuing near the forest and on the islands.”
This was the text message that Oslo residents got from city officials on a Friday afternoon in June.
May had been the warmest in 100 years. June was hot, too. By mid-July, a village south of Oslo recorded 19 days when the temperature shot up past 86 degrees Fahrenheit, or 30 Celsius, according to MET Norway.
Spring rains were paltry, which meant that grass had turned brown dry and farmers were having trouble feeding their livestock. Forests had turned to tinder. And city officials put a stop to one of the most popular Norwegian summer pastimes: heading out to the woods with a disposable barbecue.
“People not being used to this heat, they’re used to leaving a barbecue and nothing happens, Marianne Kjosnes, a spokeswoman for the Oslo Fire Department, said. “Now if a little spark catches the grass, you have a grass fire going.”
Public parks are off limits to barbecuing. So are the islands in the nearby fjord. The Oslo Fire Department’s Facebook page is trying to get the word out.
Per Evenson, a fire watchman posted in the tower on Linnekleppen, a rocky hill southeast of Oslo, counted 11 separate forest fires in one day in early July. Here and there, white smoke rose in the distance. By July 19, the civil protection department had tallied 1,551 forest fires, more than the numbers of fires in all of 2016 and 2017. The department said 22 helicopters were simultaneously fighting fires.
Wildfires were also erupting in Sweden. And one Swedish village just above the Arctic Circle, hit an all time record high, peaking above 90 degrees Fahrenheit.
“This is really frightening if this is the new normal,” Thina Margrethe Saltvedt, an energy industry analyst who lives in Oslo, wrote in an email.

Stephanie Davidson for The New York Times




Los Angeles: 108°F on July 6
At least Marina Zurkow had air conditioning.
Ms. Zurkow, an artist, has long been grappling with climate change in her work. But she was still surprised when a day of extreme weather impacted one of her projects in a big way.
The name of that project, which was designed to make people think about the impact of climate change on how we eat, is “Making the Best of It.” It is only half in jest.
“It’s both trying to make the best of a bad situation,” she said, “and in another way it’s a commitment to making things as delicious as possible.”
The latest iteration of that project was to host a dinner for a new era of dry, hot weather in California. Less Mediterranean, more Mojave Desert.
Ms. Zurkow’s partners, a team of two private chefs called Hank and Bean, prepared an elaborate meal designed to make their guests chew on the impact of climate change. The menu included sage fritters, stuffed rabbit, flatbreads made of cricket and mealworm, and jellyfish. Lots of jellyfish.
There was jellyfish crudo with a Greek salad at the top of the meal. There was a jellyfish jelly, with redwood tip infusion and pine syrup at the end of the meal.
Why jellyfish? Because it’s considered invasive and therefore plentiful, Ms. Zurkow reasoned. It’s also zero fat and good protein. “American dream food,” she added, also only half in jest.
They had planned to serve dinner al fresco in the courtyard of a downtown Los Angeles test kitchen.
But nature had other ideas.
That day, the first Friday of July, air from the Mojave blew westward and stalled, compressed and extra hot, over Los Angeles. Downtown hit a high of 108 degrees. It was too hot to eat outside.
“Even if you’re talking about climate change, you can’t torture invited guests,” Ms. Zurkow said. “We had to move the dinner into the kitchen.”

*Somini Sengupta reported from New York and Los Angeles, Tiffany May from Hong Kong, and Zia ur-Rehman from Karachi, Pakistan.

Links