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Was Climate Change Partly to Blame for Europe’s Deadly Heat Wave?

In 2003, climate change increased the risk of heat-related deaths by 70 percent in Paris and by 20 percent in London.

By Madeleine Thomas


A woman walks past a board displaying the temperature in Paris. (Photo: Thomas Coex/AFP/Getty Images)

Climate change is directly responsible for more than 500 deaths in London and Paris during the heat wave that swept Europe in 2003, according to a new study by the University of Oxford.

In the three months from June–August 2003, searing temperatures — the hottest recorded in Europe since 1540 — caused upwards of 70,000 deaths across the continent. At its height in Paris, a city largely equipped without air conditioning (and where most of the elderly population lives alone), temperatures exceeded 110 degrees Fahrenheit. As a result of funeral homes becoming so overwhelmed with the bodies of casualties, public squares were turned into makeshift mortuaries, according to reports. The heat wave was ultimately one of the 10 deadliest natural disasters to strike Europe within the last century. Almost 15,000 people died in France alone.

Researchers at the University of Oxford’s Environmental Change Institute found that anthropogenic climate change increased the risk of heat-related deaths by 70 percent in Paris and by 20 percent in London during the heat wave. Of the 315 deaths that occurred in Greater London, 64 were caused by climate change, they found. In Central Paris, 506 out of 735 deaths were related to global warming. Their study, published in Environmental Research Letters, is the first to estimate the number of premature deaths directly resulting from climate change during a severe heat wave.

“We are now at the stage where we can identify the cost to our health of man-made global warming.”

Researchers calculated the number of mortalities by combining climate model simulations of the 2003 heat wave with a national health impact assessment of death rates. But because the study only examined two cities, climate change-related mortalities are “likely to be orders of magnitude larger than this,” the study notes.

The impacts of the heat wave on infrastructure and the environment were vast:In Serbia, the waters of the River Danube evaporated to reveal once-submerged bombs and tanks from World War II; more than 500,000 acres of forest in Portugal succumbed to fire; and railway lines across the continent started to buckle, according to Met Office, the United Kingdom’s national weather service. A subsequent 2014 study by Met Office found that similar extreme heat waves are bound to become increasingly common throughout Europe — about every 127 years, rather than every 1,000 years, as scientists had once predicted.

Less than one year after the heat wave struck, the Paris Mayor’s Office developed a telephone alert system in order to check in on some of the city’s most vulnerable dwellers in the event of another catastrophe. But the causalities the previous summer had already highlighted how woefully unprepared the city was to handle severe heat. And researchers from the University of Oxford point out that policymakers should take note.

“It is often difficult to understand the implications of a planet that is one degree warmer than preindustrial levels in the global average, but we are now at the stage where we can identify the cost to our health of man-made global warming,” the Environmental Change Institute’s Dr. Daniel Mitchell said in a statement. “This research reveals that in two cities alone hundreds of deaths can be attributed to much higher temperatures resulting from human-induced climate change.”