Exclusive-Europe plans service to gauge climate change role in extreme weather

By Alison Withers and Kate Abnett

COPENHAGEN (Reuters) -The EU is launching a service to measure the role climate change is playing in extreme weather events like heatwaves and extreme rain, and experts say this could help governments set climate policy, improve financial risk assessments and provide evidence for use in lawsuits.

Scientists with the EU's Copernicus Climate Change Service told Reuters the service can help governments in weighing the physical risks posed by worsening weather and setting policy in response. 

"It's the demand of understanding when an extreme event happens, how is this related to climate change?" said the new service's technical lead, Freja Vamborg.

The European Commission did not immediately respond to a Reuters request for comment.

The service will perform attribution science, which involves running computer simulations of how weather systems might have behaved if people had never started pumping greenhouse gases into the air and then comparing those results with what is happening today.

Funded for about 2.5 million euros over three years, Copernicus will publish results by the end of next year and offer two assessments a month - each within a week of an extreme weather event.

For the first time, "there will be an attribution office operating constantly," said Carlo Buontempo, director of Copernicus Climate Change Service. 

"Climate policy is unfortunately again a very polarized topic," said Friederike Otto, a climate scientist at Imperial College London who helped to pioneer the scientific approach but is not involved in the new EU service. 

She welcomed the service's plans to partner with national weather services of EU members along with the UK Met and the Red Cross Red Crescent Climate Centre.

"From that point of view, it also helps if the governments do it themselves and just see themselves really the evidence from their own weather services," Otto said. 

RISK AND LIABILITY

Some independent climate scientists and lawyers cheered the EU move. 

"We want to have the most information available," said senior attorney Erika Lennon at the non-profit Center for International Environmental Law.

"The more information we have about attribution science, the easier it will be for the most impacted to be able to successfully bring claims to courts."

By calculating probabilities of climate change impacting weather patterns, the approach also helps insurance companies and others in the financial sector.

In a way, "they're already using it" with in-house teams calculating probabilities for floods or storms, said environmental scientist Johan Rockstroem with the Potsdam Institute for Climate Impact Research.

"Financial institutions understand risk and risk has to be quantified, and this is one way of quantifying," Rockstroem said.

In litigation, attribution science is also being used already in calculating how much a country's or company's emissions may have contributed to climate-fuelled disasters.

The International Court of Justice said in July that attribution science is legally viable for linking emissions with climate extremes - but it has yet to fully be tested in court. 

A German court in May dismissed a Peruvian farmer's lawsuit against German utility RWE for emissions-driven warming causing Andean glaciers to thaw. The case had used attribution science in calculating the damage claim, but the court said the claim amount was too low to take the case forward.

So "the court never got to discussing attribution science in detail and going into whether the climate models are good enough, and all of these complex and thorny questions," said Noah Walker-Crawford, a climate litigation researcher at the London School of Economics. 

(Reporting by Ali Withers in Copenhagen and Kate Abnett in Belem, Brazil; Writing by Katy Daigle; Editing by David Gregorio)