Human-driven climate change intensified the most recent European heatwave by as much as 4C in several cities, raising temperatures to levels that posed serious health risks to thousands of people, scientists reported on Wednesday.
This is likely to have led to far more heat-related deaths than would have occurred without the influence of global warming, a study conducted by more than a dozen researchers from five European institutions concluded.
Temperatures between late June and early July soared well above 40 degrees Celsius in many European countries, as the first heatwave of the summer broke records and triggered health warnings.
Hottest June on record
The European Union's climate monitoring service Copernicus on Wednesday said that Western Europe had seen its hottest June on record, with some schools and tourist sites shuttered as the mercury soared.
To assess what role climate change had played, scientists compared the intensity of the heatwave with one that would have occurred in a world that had not warmed due to burning of fossil fuels.
France and much of southern Europe roast as temperatures soar
Using historical weather data, they concluded that a heatwave "would have been 2-4C cooler" without human-induced climate change in all but one of the 12 cities studied.
The 4C elevation greatly increased the risk to health in the 12 cities, which included Paris, London and Madrid, and have a combined population of more than 30 million.
"What that does is it brings certain groups of people into more dangerous territory," said researcher Ben Clarke from Imperial College London, which co-led the study with the London School of Hygiene and Tropical Medicine.
"For some people it's still warm, fine weather. But for now a huge sector of the population, it's more dangerous."
Death toll
The study also sought to estimate the death toll from the heatwave in the 12 cities studied, and how many of these deaths could be attributed to climate change.
Based on peer-reviewed scientific methods and established research on heat and mortality, the study concluded that the heatwave likely caused around 2,300 deaths between 23 June and 2 July across the 12 cities studied.
Around 1,500 of these deaths would not have occurred had climate change not pushed temperatures to such dangerous highs, researchers said, whole stressing that this was an estimate as no official death toll was not yet available.
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Heatwaves are particularly dangerous for the elderly, those with health conditions, young children, outdoor workers and anyone exposed to high temperatures for prolonged periods without relief. The impact on health is also compounded in cities, where heat is absorbed by paved surfaces and buildings.
Copernicus said large parts of southern Europe experienced so-called "tropical nights" during the heatwave, when overnight temperatures don't fall low enough to let the body recover.
"An increase in heatwave temperature of just two or four degrees can mean the difference between life and death for thousands of people," said Garyfallos Konstantinoudis, a lecturer at Imperial College London. "This is why heatwaves are known as silent killers. Most heat-related deaths occur in homes and hospitals out of public view, and are rarely reported."
Authorities say it could take weeks to calculate a definitive death toll from the recent heatwave, but similar episodes have claimed tens of thousands of lives in Europe during previous summers.
(with AFP)
