This picture taken on July 9, 2019 in Paris shows Notre-Dame de Paris cathedral as reconstruction works are ongoing after it was badly damaged by a huge fire last April 15. (Photo by BERTRAND GUAY / AFP)        (Photo credit should read BERTRAND GUAY/AFP/Getty Images)
Bertrand Guay/AFP/Getty Images
This picture taken on July 9, 2019 in Paris shows Notre-Dame de Paris cathedral as reconstruction works are ongoing after it was badly damaged by a huge fire last April 15. (Photo by BERTRAND GUAY / AFP) (Photo credit should read BERTRAND GUAY/AFP/Getty Images)
Now playing
01:43
Heat wave puts iconic landmark in jeopardy
CNN
Now playing
03:29
Meet teen climate activist Greta Thunberg
Shutterstock
Now playing
01:13
What you can actually do to slow the climate crisis
Now playing
02:30
The Road to Change: America's Climate Crisis
Now playing
03:18
Climate crisis in Alaska is impacting the entire world
faces of climate change orig nws_00005521.jpg
faces of climate change orig nws_00005521.jpg
Now playing
01:46
How climate change is changing lives
climate change 97 percent consensus orig_00005513.jpg
climate change 97 percent consensus orig_00005513.jpg
Now playing
02:29
Scientists agree: Climate change is man-made
Democratic presidential candidate Elizabeth Warren participates in CNN's climate crisis town hall in New York on September 4, 2019.
Edward M. Pio Roda/CNN
Democratic presidential candidate Elizabeth Warren participates in CNN's climate crisis town hall in New York on September 4, 2019.
Now playing
03:28
See how candidates stood out in 7 hours of climate talk
Democratic presidential candidate Elizabeth Warren participates in a climate crisis town hall hosted by CNN in New York on September 4, 2019.
Edward M. Pio Roda/CNN
Democratic presidential candidate Elizabeth Warren participates in a climate crisis town hall hosted by CNN in New York on September 4, 2019.
Now playing
01:51
Warren: Where Trump is right now is a nightmare
CNN
Now playing
02:41
Biden: Military warned us of climate crisis danger
Democratic presidential candidate Bernie Sanders participates in CNN's climate crisis town hall in New York on September 4, 2019.
Edward M. Pio Roda/CNN
Democratic presidential candidate Bernie Sanders participates in CNN's climate crisis town hall in New York on September 4, 2019.
Now playing
01:46
Sanders: Trump's stance on climate change is idiotic
CNN
Now playing
02:03
Harris on Trump: Lead or get out of the way
CNN
Now playing
00:56
Yang: You know what's expensive? Poisoning our kids
Democratic presidential candidate Beto O'Rourke participates in CNN's climate crisis town hall in New York on September 4, 2019.
Edward M. Pio Roda/CNN
Democratic presidential candidate Beto O'Rourke participates in CNN's climate crisis town hall in New York on September 4, 2019.
Now playing
01:54
O'Rourke: We need to support the people of Puerto Rico
Democratic presidential candidate Pete Buttigieg participates in CNN's climate crisis town hall in New York on September 4, 2019.
Edward M. Pio Roda/CNN
Democratic presidential candidate Pete Buttigieg participates in CNN's climate crisis town hall in New York on September 4, 2019.
Now playing
01:25
Pete Buttigieg: I would ask Trump to step aside
Democratic presidential candidate Elizabeth Warren participates in a climate crisis town hall hosted by CNN in New York on September 4, 2019.
Edward M. Pio Roda/CNN
Democratic presidential candidate Elizabeth Warren participates in a climate crisis town hall hosted by CNN in New York on September 4, 2019.
Now playing
02:25
Warren: This is what fossil fuel wants us talking about
julian castro 9.4
CNN
julian castro 9.4
Now playing
03:23
Student calls out Julian Castro's record on fracking
(CNN) —  

Europe is sweltering in intense heat, suffering through the latest heat wave in a summer that has seen at least 12 countries experience record-breaking temperatures.

Meteorologists say that Europe is on track for the hottest July on record, following the warmest June since records began in 1880.

Scientists warn that the world should expect more scorching heat waves due to climate change and that current temperature highs are in line with predictions made over a decade ago.

People cool off in the fountains in Aalborg, Denmark, on July 24, 2019.
HENNING BAGGER/AFP/Getty Images
People cool off in the fountains in Aalborg, Denmark, on July 24, 2019.

Record-breaking temperatures

Belgium, Germany, the Netherlands and the UK all reached record-breaking temperatures this week.

On Wednesday, Belgium endured its hottest day ever recorded, with temperatures rising to 39.9 degrees Celsius (102 Fahrenheit). The Netherlands broke a 75-year record on Wednesday, and then hit another all-time high of 40 Celsius (104 Fahrenheit) on Thursday, the national weather forecasting institute said. Temperatures there are still climbing.

In the German town of Geilenkirchen, a temperature high of 40.5 degrees Celsius (104.9 Fahrenheit) was recorded on Wednesday. The UK experienced its hottest ever July day on Thursday, with temperatures predicted to beat the hottest ever recorded temperature of 38.5 Celsius, set in 2003.

All four countries remain on extreme heat alert.

In June, a heat wave broke temperature records in eight countries, including France, the Czech Republic and Switzerland.

France reached a scorching 45.9 degrees Celsius (114.6 Fahrenheit). The country is on high alert again, with temperatures of 42 Celsius (107.6 Fahrenheit) expected in Paris.

The current heat wave presents a serious threat to Notre Dame Cathedral. The roof of Paris’ beloved cathedral, which survived a massive fire months ago, is at risk of collapse, according to chief architect Philippe Villeneuve.

“What I fear is that the joints or the masonry, as they dry, lose their coherence, their cohesion and their structural qualities and that all of sudden, the vault gives way,” he said.

More intense heat waves

Heat waves such as this one could become the new normal for Europe, driven by rising temperatures caused by greenhouse gas emissions, scientists say.

“Climate change is without doubt ‘loading the dice’ and making heat waves much more likely and much more severe,” according to Michael Byrne, professor of earth and environmental sciences at the University of St Andrews, in Scotland.

A group of European scientists concluded that the June heat wave was made at least five times more likely because of climate change – and perhaps 100 times more likely.

France’s weather service also made the link, issuing a warning that without serious carbon dioxide reductions, heat waves could become more intense and frequent than in the past.

Mass disruption

While temperatures around 100 degrees Fahrenheit might not seem high in comparison to some other parts of the world, they are way above seasonal averages for much of Europe.

Many European cities are not designed to deal with such temperatures. Less than 5% of all European households have been air-conditioned, according to a 2017 report, and public transport can grind to a halt in intense heat.

Blue skies behind the Eiffel Tower in Paris on July 23, 2019.
PHILIPPE LOPEZ/AFP/Getty Images
Blue skies behind the Eiffel Tower in Paris on July 23, 2019.

Amid the sweltering heat, trains were canceled in a number of European countries due to risk of derailment.

A Eurostar train traveling from Belgium to London broke down on Wednesday, trapping passengers in 40 degrees Celsius heat, without air conditioning.

Network Rail, which operates the UK’s rail infrastructure, said that track temperatures in and around London were set to exceed 50 Celsius (122 degrees Fahrenheit), almost double the average summer rail temperature in the UK.

Railway tracks expand in heat and are prone to buckling when temperatures rise.

One solution is to paint rail tracks white to reflect the sun’s heat, according to John Easton, a rail expert at the Institution of Engineering and Technology.

“This can reduce the track temperature by 5°C and reduces signaling failures which lead to significant disruption,” he said, adding that Italy uses the technique to lower the risk of buckling.

It is not just public transport that is grinding to a halt because of the heat. In southern France, EDF energy group closed its nuclear power plant as temperatures rose above 40 Celsius (104 Fahrenheit).

“The reason for the cut in output is not because of a technical problem, but an environmental one regarding heating up the river water beyond what is safe for marine life,” according to a spokesperson for the Nuclear Industry Association.

Health risks

Heat waves pose serious health risks and can cause cardiovascular and respiratory systems to fail, resulting in premature death, Clare Heaviside, of the University of Oxford’s Environmental Change Institute (ECI), told CNN.

Elderly people are most at risk as they are more prone to heatstroke. Experts advise they should keep windows closed and pull blinds down during the hottest part of the day.

Planning for extreme weather

European countries must accept the reality of climate change and learn to adapt to extreme weather events, according to Dr Friederike Otto, director of the ECI.

Otto said that France took important mitigation measures after a heat wave in 2003 contributed to tens of thousands of premature deaths.