Heatwaves pose increasing global health risk, say scientists

Heatwaves linked to climate change pose an increasing danger that threatens to overwhelm health services around the world, a hard-hitting report has said.

Vulnerability to extreme hot weather has risen steadily on every part of the planet since 1990, say the authors.

In 2017, 157 million more people were exposed to heatwaves than in 2000, the report said.

During same year 712 extreme weather events resulted in global economic losses of 326 billion US dollars (£255 billion) – almost triple the previous year.

Europe and the eastern Mediterranean were more at risk from heatwaves than other regions such as Africa and south-east Asia, according to the authors.

This was probably due to the larger number of older people living in cities in those parts of the world.

On average, everyone on Earth was exposed to an additional 1.4 days of heatwave between 2000 and 2017 compared with the period 1986-2005.

People vulnerable to heatwaves were defined in the report as adults over the age of 65, city dwellers, and those living with heart disease, diabetes and chronic lung conditions.

The scientists analysed a range of indicators providing a picture of climate change impacts and vulnerability, health resilience, economics and adaptation to global warming.

Findings from the Countdown on Health and Climate Change report are published in The Lancet medical journal.

Lead researcher Professor Hilary Graham, from the University of York, said: “Present-day changes in heatwaves and labour capacity provide early warning of the compounded and overwhelming impact on public health that is expected if temperatures continue to rise.

“Trends in the impacts of climate change, exposures and vulnerabilities show unacceptably high risk for health now and in the future.

“The lack of progress in reducing emissions and building adaptive capacity threatens lives and health systems and must be addressed to avoid disruption to core public health infrastructure and overwhelming health services.”

The report found that while average global temperatures rose by 0.3% between 1986 and 2017 the impact on human populations was much greater.

The average temperature increase people were exposed to over the same period was 0.8C.

Heat rising above physiological limits made sustained work more difficult or impossible, the authors said.

In 2017, 153 billion hours of labour were lost due to heat exposure, an increase of 62 billion hours since 2000.

Co-author Professor Joacim Rocklov, from Ulmea University in Sweden, said: “Vulerability to expreme heat has steadily increased around the world since 1990. This has led to vast losses for national economies and household budgets.”

The researchers also stressed the growing threat of infectious diseases spread in drinking water and by mosquitoes.

In 2016 the global capacity for the transmission of dengue fever by mosquitoes was the highest on record.

Between the 1950s and 2016, the malaria threat in the highlands of sub-Saharan Africa increased by 27.6%.

The scientists concluded: “Taken as a whole, the indicators and data presented in The Lancet Countdown’s 2018 report provide great cause for concern, with the pace of climate change outweighing the urgency of the response.”

However they added that there were “exciting trends” in key areas such as phasing out coal, cleaner forms of transport, and health system adaptation that justified “cautious optimism”.