Dr. Madeleine Thomson on Urban Adaptation and the Rising Toll of Extreme Heat
Last summer, southern Europe sweltered through 23 tropical nights—when temperatures never dip below 20°C—nearly triple the average and far surpassing any previous record. The consequences were deadly: across 854 European cities, an estimated 24,400 people died from heat-related causes between June and August alone.
“Europe is heating up, and we’re not prepared for the toll this will take on our health,” says Dr. Madeleine Thomson, Head of Climate Impacts & Adaptation at Wellcome. “Deaths from heat stress are the most visible impact. But extreme heat doesn’t just kill—it also increases the risk of heart disease, pregnancy complications, and poor mental health.”
Thomson should know. With over 25 years of research experience focused on climate-sensitive health interventions, she previously directed the World Health Organization Collaborating Centre on Early Warning Systems for Malaria and Other Climate Sensitive Diseases at Columbia University’s International Research Institute for Climate and Society. Now at Wellcome, she leads work on helping communities adapt to the health impacts of our warming world.
The Silent Killer in Our Homes
The sobering reality is that most heat deaths don’t happen on construction sites or during marathons. They happen quietly, in homes and hospitals, where people with existing health conditions are pushed beyond their limits. Older adults are especially vulnerable—85% of last summer’s heat deaths in Europe occurred among people over 65.
“The vast majority of heat deaths happen in homes and hospitals, where people with existing health conditions are pushed to their limits,” explains epidemiologist Garyfallos Konstantinoudis, who co-authored a recent study on the crisis. “But heat is rarely mentioned on death certificates.”
This invisibility makes heat a particularly insidious threat. Unlike hurricanes or floods, extreme heat doesn’t produce dramatic footage or inspire immediate action. Yet the numbers are staggering. Britain’s scorching summer of 2022 saw an estimated 2,800 extra deaths among people over 65 from heat-related causes.
Children face heightened risk too, warming up faster due to their smaller body size. Pregnant women, whose bodies already struggle with temperature regulation, are also particularly vulnerable to heat stress.
Why Cities Are Heat Traps
Urban areas face an additional challenge: the “urban heat island effect.” Buildings, asphalt, and concrete absorb and trap heat, making cities significantly hotter than surrounding rural areas. When nighttime temperatures refuse to drop, there’s no recovery period for bodies already stressed by daytime heat.
“Nighttime temperatures are really important for our health because it’s the part of each day when we recover,” notes Dann Mitchell from the UK’s Met Office. “And if it can’t do that, it brings a whole host of issues.”
The economic consequences ripple outward. Farmers grapple with withering crops and crusty soils. Last year’s wine harvests across southern Europe were described by the industry as “dismal” and “horrible.” In Italy, pavements melted. Near Athens, fires burned through 11,000 hectares.
What Actually Works
The encouraging news is that solutions exist—and some cities are already implementing them successfully.
“We urgently need to cut emissions and adapt our cities,” Thomson emphasizes. “Simple changes, like adding green spaces and waterways, can help cool urban areas and protect public health.”
Green spaces aren’t just aesthetic improvements; they’re public health infrastructure. Trees provide shade and release moisture through evapotranspiration, naturally cooling surrounding areas. Urban waterways and fountains offer similar benefits. These interventions are particularly crucial in densely built neighborhoods where vulnerable populations often live.
Beyond greening cities, heat action plans save lives. These include:
Early warning systems that alert vulnerable populations when dangerous heat is approaching, giving people time to prepare and authorities time to mobilize resources.
Cooling centers in public buildings where people without air conditioning can escape the heat during the most dangerous hours.
Adjusted work schedules that prevent outdoor labor during peak heat. After a 47-year-old construction worker died near Bologna during a heatwave, regional authorities finally implemented orders to stop outdoor construction work during early afternoon heat.
Targeted support for vulnerable groups, including air conditioning for retirement homes and wellness checks on isolated elderly residents.
A Continent Warming Faster Than Most
Europe faces a particular challenge: it’s warming twice as fast as the global average, partly due to its overlap with the rapidly heating Arctic. While scientists can’t predict the exact number of tropical nights or heat waves in any given year, the trend is unmistakable and accelerating.
The record-breaking summer of 2024 wasn’t an anomaly—it was part of a long-term shift. Southern European destinations experienced 66 days of “strong heat stress,” when daily temperatures reached a feels-like temperature of 32°C or higher, far surpassing the average of 29 days.
Tourist patterns are already shifting in response. Travel companies are scrapping hiking holidays in Turkey during July and August, instead running new summer trips to Scandinavia, where bookings from British tourists jumped 40% last year. Google has detected rapidly growing searches for “summer holiday in Europe not too hot” and “what summer holiday destinations do not have risk of wildfires in July.”
The Path Forward
Cities are better prepared than they were during the devastating 2003 heatwave that killed 70,000 people across Europe. But emergency services are struggling to keep pace with rising temperatures and aging populations.
“Extreme heat kills—and these new data show that no city in Europe is immune,” Thomson warns. “Climate change is driving up temperatures, and with them, not just deaths but serious illnesses including heart attacks, kidney disease, miscarriages, and mental health crises.”
The solution requires action on two fronts. First, we must rapidly cut greenhouse gas emissions to limit further warming. Second, we need immediate adaptation measures to protect people from the heat we’ve already locked in.
“If we don’t act now, the toll will rise,” Thomson says. “We must urgently phase out fossil fuels and implement policies that protect those most at risk from increasingly deadly heatwaves.”
The question isn’t whether your city will face another record-breaking heatwave. It’s whether your city will be ready when it does.