2003 European Heatwave: The Summer That Killed Tens of Thousands

The 2003 European heatwave was a prolonged spell of extreme heat that gripped western and central Europe in the summer of 2003, reaching its peak in the first half of August. It caused an estimated 70,000 excess deaths, mostly among elderly people, making it one of the deadliest natural disasters in modern European history. France was hit hardest relative to its preparedness, and the crisis transformed how European countries plan for heat.

Causes

The summer began with an unusually hot June. In late July a strong, slow-moving area of high pressure, an anticyclone, settled over western and central Europe and remained there for weeks. It blocked rain-bearing weather systems from the Atlantic, bringing clear skies and intense sunshine day after day.

Dry soils made things worse. With little moisture to evaporate, more of the sun’s energy went into heating the ground and the air. Warm nights, especially in large cities where buildings and pavements retain heat, gave people little chance to recover.

At the time, climate scientists judged that summer 2003 was probably the hottest in Europe for at least 500 years. In 2004 a study in the journal Nature by Peter Stott and colleagues concluded that human influence on the climate had at least doubled the risk of a heatwave of that severity, one of the first studies to attribute a specific extreme weather event partly to climate change.

What happened

Temperatures above 35 C became routine across much of France, northern Italy, Switzerland, southern Germany and the Iberian Peninsula. Portugal recorded 47.3 C at Amareleja on 1 August. Switzerland set a national record of 41.5 C at Grono, and on 10 August the United Kingdom recorded 38.5 C at Faversham in Kent, its first reading above 100 F.

Wildfires burned large areas of Portugal, where more than 400,000 hectares of forest and scrub were lost in 2003, and fires also struck Spain, France and Italy. Rivers fell to very low levels, harvests of wheat and other crops dropped sharply, and Alpine glaciers lost an exceptional amount of ice. In France, the electricity company EDF had to reduce output at some nuclear power stations because river water was too warm to cool them safely.

The death toll

The heat was most dangerous for the elderly, people with chronic illnesses and those living alone. A study led by Jean-Marie Robine, published in 2008, estimated more than 70,000 excess deaths in 16 European countries over the summer. Excess deaths are the number of deaths above what would normally be expected for that time of year.

France recorded nearly 15,000 excess deaths between 1 and 20 August, according to the national health research institute Inserm. Italy and Spain each suffered many thousands of deaths, and Germany, Portugal, the United Kingdom and the Netherlands thousands more. Estimates differ between studies depending on the period and method used.

The crisis in France

In France the disaster struck during the August holidays, when many families, doctors and officials were away. Many victims died alone in top-floor flats under hot roofs; some were not found for days. Hospitals and funeral services in Paris were overwhelmed, and a refrigerated warehouse at the Rungis wholesale market outside Paris was used as a temporary morgue. Weeks later, the bodies of dozens of people whose families had not come forward were buried by the city.

The government was criticised for reacting slowly. The health minister, Jean-François Mattei, faced heavy criticism, and the director-general of health, Lucien Abenhaïm, resigned in August 2003. A parliamentary inquiry examined failures in monitoring and care for older people.

Legacy

France introduced a national heatwave plan (Plan Canicule) in 2004, with an alert system run with the weather service Météo-France, registers of vulnerable people kept by town halls, and air-conditioned rooms in care homes. To help fund care for the elderly and disabled, it also created an annual “solidarity day”, originally set on Whit Monday, when employees work without extra pay.

England launched its first Heatwave Plan in 2004, and the World Health Organization encouraged heat-health action plans across Europe. Later heatwaves, including those of 2019 and 2022, broke many of the 2003 records, and they have kept the summer of 2003 at the centre of debates about climate change and international efforts to curb it, from the Kyoto Protocol to the Paris Agreement.

By the numbers

Timeline

• 2003, June: An exceptionally hot month across much of western Europe.
• 2003, late July: A blocking anticyclone settles over western and central Europe.
• 2003, 1 August: Portugal records 47.3 C at Amareleja.
• 2003, 10 August: The United Kingdom records 38.5 C at Faversham, Kent.
• 2003, 1-15 August: The heat peaks; deaths in France surge.
• 2003, 18 August: France’s director-general of health, Lucien Abenhaïm, resigns.
• 2004: France launches its national heatwave plan, and England publishes its first Heatwave Plan.

Why it matters

The 2003 heatwave showed that heat can kill on the scale of a major earthquake, yet quietly and largely out of sight. It turned heat into a recognised public health emergency in Europe and became a reference point for understanding how a warming climate makes such summers more likely.