Why this latest European heatwave is so different – and more worrying

Independent

9 hours ago

Europe is burning. This week, we have seen heatwaves across southern Europe, sparking blazes from Portugal to the Balkans. Spain broke its hottest temperature record on 28 June, and on Wednesday, the country was battling its 10th consecutive day of extreme heat. With the heatwave expected to last until Monday, it is set to become one of the longest the country has ever experienced.
We have seen the biggest wildfires in France since 1949, with an area around the size of Paris burning in a very short period. Fires have raged on the outskirts of Naples and are currently out of control in Greece, which has requested EU water bombers to aid nearly 5,000 firefighters tackling more than 20 blazes.
The combination of drought, heatwaves, and wildfires has become common in 2025. We are now in a period of 'compound hazards', when two or more climate events affect each other. For example, landslides caused by fires followed by intense rainfall or flooding – these are multiple extreme environmental occurrences happening either at the same time or one after the other.
I have researched heatwaves for six years and helped develop parts of early warning systems for heat. We can often tell three months in advance if a specific summer season is particularly at risk of heatwaves, as was the case this year.
We could see it in above-average temperature charts and sea surface pressure patterns, which allowed us to predict this summer's heat with high confidence very early on. It is more difficult to forecast droughts and rainfall; in these cases, we make use of teleconnections – links with weather patterns found in other parts of the world, such as El Nino – to look at how this might influence the weather in Europe.
The broad definition of a heatwave is three or more days of above-average temperatures during a region's warm season; local countries have different variations on this. Heatwaves in Europe are caused by blocking high-pressure systems (settled areas of air that act similarly to an oven). We know that with the climate crisis, the frequency, intensity, and duration of heatwaves are increasing, and the area exposed is greater.
We saw five heatwaves in the summer of 2022, when temperatures in the UK hit a record 40.3C.
The heatwave currently affecting central Europe and parts of the UK is interesting because it is the result of an ex-tropical storm, Dexter, interacting with high pressure over Europe, which is causing it to move up over parts of the UK. This has meant that we experienced rainfall in the middle of this heatwave, something we also saw during the August 2003 heatwave.
It's a trend we need to be alert for in the future, because the indication is that summer storms, as well as heatwaves, could be a problem. We have yet to focus research on this and need to more work on these interactions.
Until recently, as a country, Britain would get excited about a coming heatwave; paddling pools would be hastily pulled out of sheds, and barbecues and beach trips arranged. But as heatwaves have become more common, they have become more of a concern. People struggle to sleep and heat extremes slow down workers, reduce working hours, and cut output, especially in outdoor sectors such as construction, transport, and tourism. They can also wear down transport systems, strain power grids, and worsen air quality.
We are also realising how heatwaves are silent killers. They cause deaths every time they occur, and it is estimated that up to 2,000 people may have died in the July 2025 heatwave across Europe. They also cause a rise in hospitalisations and ambulance service callouts. In London, during the July heatwave, the ambulance service received more than 7,000 calls, increasing pressure on an already struggling health system.
Heatwaves pose significant risks for all ages, from the elderly to the very young. I have led research on the impact of heat on maternal, newborn, and children's health, which shows evidence of an increased risk of preterm birth with heat exposure. There is also a rise in accidental deaths and drowning during heatwaves, as young people rush to rivers and the seaside.
It is really important for everyone to keep cool – not just vulnerable people.
Heatwaves affect our environment in interesting ways too – both on land and at sea. We've seen an influx of non-typical species in British waters, such as European sardines, anchovies, pilchards, and even some octopuses, with traditional species such as Atlantic herring and European sprat migrating further north.
On land, freshwater ecology is affected, as is the capacity of rivers to act as coolers for cities during heatwaves. During low flows caused by drought, a river's ability to cool is reduced, as shown in a study of the River Don in Sheffield. This year's heatwaves are already having an impact on crop yields.
One crop particularly susceptible to the heat is broccoli, which prefers a maximum growing temperature of 23C – hence there will be smaller heads of broccoli, and possibly shortages. Other crops affected include wheat, barley, and potatoes. Price rises often follow heatwaves, as was the case with bread in the UK after a number of European heatwaves, because of the impact on cereal crops.
The pattern of when and where people holiday is already starting to shift, and it is likely that holiday habits will continue to change. While some may opt for a more temperate UK climate, it will be important to support communities whose livelihoods depend on tourism – and these communities are often the same ones that are affected by wildfires. Tourists may now opt for a spring or autumn break in Greece, instead of visiting in high summer.
How we work will change the number of breaks a person needs, and safe environments need to be considered. Urban planning will be affected, too. More trees are being planted in many cities as a source of shade, and investment in cooling strategies for urban areas is urgently needed. In France, a row is brewing over the excessive use of air-conditioning systems, dubbed by some 'an environmental aberration', but there are innovative approaches, such as using the River Seine to cool Paris, or misting fans in Novi Sad, Serbia.
Looking to the future, we will need to work together across sectors and policy, which can be challenging when people are accustomed to working in silos. We didn't act to mitigate the emissions driving climate change, so we now need to focus on adapting our lives to the changing conditions, while also reducing emissions.
We need to assess the use of air-conditioning for the most vulnerable in places like schools and hospitals. On an individual level, we need to talk about climate change with family and friends, discuss the risks, and stay safe during heatwaves while conserving water during droughts. One surprising hack I've seen is the use of yoghurt on windows to keep a house cool during summer. Many of my friends and family also know to cool their hands and necks first if they are feeling too hot.
The richest in society produce the most emissions, but we are seeing we're not immune to some of the impacts. My hope is that this will make the transition to net zero more urgent, and encourage us to work together to understand how our actions matter and how the severity of these events can be prevented from increasing in the future.