Steamy Nights in European Heatwave Worsen Health and Fire Risks: Experts

By Gloria Dickie

July 20, 2022

LONDON (Reuters) - Hot night time temperatures are hindering firefighting responses across Europe and worsening health conditions as bedtime fails to provide a cooling reprieve, experts said on Tuesday.

On Monday, Britain experienced its warmest night on record with temperatures failing to dip below 25 Celsius (77F) in some places. Meanwhile, La Hague in Normandy, France, registered 32.8C at 3 a.m. on Tuesday.

Across much of the planet, night time temperatures are actually rising at a faster rate than day time temperatures under climate change.

"Hotter nights means people and our environment don't get a break from climate change," said Jennifer Balch, a fire ecologist at the University of Colorado Boulder in the United States.

In a February 2022 study in the journal Nature, Balch and her team found that the cool, damp nights which once helped tame roaring wildfires are disappearing.

"Nights have gotten 25% hotter and drier globally over the past 40 years," said Balch, noting a 36% increase in the number of after-dark hours that are warm and dry enough to sustain fire.

This means that exhausted firefighters aren't getting a respite. Currently, some 1,700 firefighters are battling blazes around France's coastal Gironde region. Many more have been dispatched to fires in Spain and Portugal.


Hot nights can also take a toll on people's physical and mental health.

"Sleep is interrupted for many people during heatwaves," said Laurance Wainwright, an environmental lecturer at the University of Oxford.

Poorer sleep quality or shorter sleep duration can worsen outcomes in those with major depressive disorder. "Tossing and turning and sweating—a few days of that for some people can be problematic," he said.

Sweltering nights following steamy days can also make it difficult for people to recover.

"The body is trying to get to a lower temperature and that is stressful for the cardiovascular system and respiratory system and keeps the heart rate high," said Dominic Roye, a climatologist at the University of Santiago de Compostela in Spain.

Roye was previously involved with a pilot study examining the effect of hot nights on mortality in southern Europe. The results, he said, showed a clear link, particularly for people suffering from cardiovascular conditions.

"If you have this kind of high temperature environment you cannot achieve deep sleep," he said.

While healthy people might just feel tired the next day, this can prove fatal for those with underlying medical conditions, he added.

(Reporting by Gloria Dickie in London; Additional reporting by Aislinn Laing and Emma Pinedo in Madrid, Editing by Alexandra Hudson)