Climate Urban greening could significantly reduce the number of heat victims
More plants in cities could significantly reduce the number of heat victims. If vegetation in urban areas were to increase by 30 percent worldwide, the number of heat-related deaths would fall by around a third, according to a study.
03.05.2025, 06:30
SDA
The international research team led by Yuming Guo from Monash University in Australia writes in the journal "The Lancet Planetary Health" that city dwellers in Southern and Eastern Europe as well as in South and East Asia could benefit particularly strongly from the greenery.
As global warming increases, so does the risk of heat-related health problems - especially for children and the elderly. City dwellers are considered to be particularly at risk because cities heat up more during the day and cool down more slowly at night. Only recently, a German study for Karlsruhe showed that increasing the tree population there by at least 30 percent could reduce the annual number of extreme heat hours by almost two thirds.
Europe and Asia would benefit particularly strongly
In the current modeling study for the period from 2001 to 2019, the team simulated how increased greening would have affected mortality in more than 11,000 urban areas worldwide. Heat-related mortality depends on many factors, including the climate zone, the proportion of green space and demographic factors such as people's age. The team used information from 830 locations in 53 countries - including 15 German cities. It used satellite-based data to calculate the proportion of vegetation in the cities.
According to the simulations, a 30 percent increase in vegetation would have saved up to 1.16 million lives during the period - equivalent to almost 37 percent of all heat-related deaths in cities during the summer. According to the study, almost 400,000 of these would have been in Europe and almost 530,000 in Asia, compared to around 70,000 in North America and 36,000 in Africa.
Green roofs and façades as an option
"These results indicate that the preservation and expansion of green spaces could be possible strategies to reduce the temperature and mitigate the health consequences of heat," said study leader Guo. Overall - i.e. worldwide and not just limited to summer and cities - around 500,000 people die from heat each year; this corresponds to around 0.9 percent of all deaths, according to the study.
Depending on the climate scenario, this proportion could rise significantly by the end of the century. To prevent this, the team recommends above all expanding green spaces in cities, including by greening roofs and facades.
Trees in particular cool the urban climate in summer and also have other benefits: They provide shade for people, animals and other plants, cool asphalt and concrete, increase humidity through evaporation, absorb fine dust, reduce noise and provide habitats for many animals such as birds and insects.
