Heatwave. Picture: 123RF
Heatwave. Picture: 123RF

Sydney — Extreme weather that is gripping northern Europe and parts of Asia may persist into early August, prolonging a deadly heatwave that has parched crops and sparked devastating forest fires.

Temperatures have risen to a record from Japan to Norway because of a stationary blocking high-pressure system, the World Meteorological Organization (WMO) said on Tuesday. Relief from soaring temperatures — which topped 30°C in the Arctic Circle — may not arrive for at least two weeks, potentially extending a spate of weather-related disasters from wildfires near Athens to floods in Laos.

"It’s quite remarkable how long it’s lasting," Andrew King, a climate scientist at the University of Melbourne, said in a phone interview. "At the moment, the forecast is for not much change."

The World Economic Forum ranks extreme weather as the top global risk in terms of likelihood and second-biggest in terms of impact, while the WMO says episodes of extreme heat and precipitation are increasing due to climate change.

This week, hundreds of people went missing in deadly floods caused by a collapsed dam in Laos following heavy rainfall, while at least 74 people were killed in the worst fires to hit Greece in at least a decade. They add to six deadly weather and climate events in the US in 2018 that have each caused losses exceeding $1bn.

Thunderstorms and wildfires

In northern Europe, continued drought over the next two weeks may be accompanied by local thunderstorms, risks of wildfires and harvest losses, the Geneva-based WMO said.

Globally, June was the second-warmest on record, according to the European Centre for Medium Range Weather Forecasts’ Copernicus Climate Change Service. So far, 2018 is the hottest La Niña year on record. The previous three years were confirmed as the warmest years on record, indicating continuing long-term climate change caused by increasing atmospheric concentrations of greenhouse gases.

A blocking weather pattern that weakens the jet streams churning through the upper atmosphere are widely understood to be driving the heatwaves, said Andy Pitman, director of the ARC Centre of Excellence for Climate Extremes at the University of New South Wales in Sydney.

"The question is, how have the mechanisms that have caused the heatwaves been perturbed by human activity?" Pitman said in an interview. "We are basically uplifting the entirety of the climate system by the energy we are pumping into it through greenhouse gases."

Global warming

"The frequency, magnitude and duration of heatwaves are all getting worse," Pitman said. "You can’t get events like we are now seeing in terms of spatial distribution, intensity and increasing frequency without there being quite a significant contribution from global warming."

The changes are leading to increases in financing for climate mitigation and resilience. The Manila-based Asian Development Bank said earlier in July that financing for this purpose increased 21% to a record $4.5bn in 2017. Climate financing by the world’s six largest multilateral development banks reached a seven-year high of $35.2bn in 2017, up 28% from the previous year.

"Every dollar spent on reducing risks and their impacts before a disaster saves five dollars in future losses," Alison Martin, Zurich Insurance Group’s chief risk officer, said in a statement in June. "That means it’s five times more expensive to be unprepared."