France raises heat alerts as Europe swelters in early summer wave

France put about half its mainland departments under the highest heat warning Tuesday as an early summer heat wave pushed temperatures above 40 degrees Celsius, or 104 degrees Fahrenheit, in many towns. The conditions have disrupted schools, transport and public events across Europe, while French officials reported 40 drowning deaths in the past week as people sought relief in water.

Meteo France, the national weather service, placed 54 of the country’s 96 mainland departments on red alert. The agency said temperatures would stay high day and night, with the severe spell expected to last at least through the end of the week.

French Prime Minister Sébastien Lecornu said the 40 people who drowned since last Thursday were mainly young people. The Associated Press reported that France’s limited use of air conditioning has left schools, public transportation and sporting events more exposed to the heat.

Meteo France said more records could fall, including marks for any time of year. The agency described the heat wave as unusually intense for so early in the summer, while saying its duration remained uncertain.

Forecasters and officials have drawn comparisons with France’s August 2003 heat wave, when the highest temperatures in more than 50 years were linked to an estimated 15,000 deaths, many among older people in apartments and retirement homes without air conditioning, according to the Associated Press.

Britain and Spain also issue warnings

The heat extended beyond France. In Britain, the Met Office issued a red extreme heat warning for Wednesday and Thursday, and many schools said they would close for the day, according to the Associated Press.

The Met Office forecast temperatures around 37 degrees Celsius, or 98.6 Fahrenheit, in southern England and up to 35 Celsius in southeast Wales. The agency said the peak was expected Wednesday and Thursday, when highs could reach at least 39 Celsius, before conditions ease by Friday.

Rail service also faced restrictions. Several U.K. train operators said they were canceling services to maintain safe operations, while National Rail urged people to travel only if necessary on Wednesday and Thursday, according to the Associated Press.

Spain’s national weather service, Aemet, issued red alerts Tuesday for parts of Andalusia, where temperatures were forecast to reach 44 Celsius, or 111 Fahrenheit. Aemet also warned that temperatures could hit 40 Celsius in Cantabria and the Basque Country, regions on Spain’s normally milder northern Atlantic coast.

Aemet meteorologist Rubén del Campo said Spain is expected to grow hotter as climate change makes heat waves more frequent, longer and less confined to July and August. He said Aemet has recorded a dozen June heat waves since it began tracking them in 1975, with half occurring since 2015.

Climate agencies warn of rising heat risks

Human-caused climate change is linked to more extreme weather, according to climate scientists cited by the Associated Press. Projections from the United Nations climate agency say more heat records are likely to be broken over the next five years.

Europe is warming faster than any other continent, with temperatures rising twice as quickly as the global average since the 1980s, according to the European Union’s Copernicus Climate Change Service. The World Health Organization’s Europe office said this month that more than 200,000 people in Europe died from heat-related causes over the past four years, and that most of those deaths were preventable.

This story draws on original reporting from Fortune.