PLANTING MORE TREES in cities could prove to be an important step towards reducing the number of deaths that occur due to high temperatures in summer months, a new study has found.

Increasing tree cover up to 30% can lower the temperature of urban areas by nearly half a degree Celsius, enough to prevent some heat-related deaths.

Currently, the average tree cover in European cities is 14.9%.

The researchers studied 93 European cities and used mortality data from June to August 2015, as well as daily average city temperatures, to determine the role of tree cover in saving lives.

Using a simulation of the temperature reduction that would come as a result of increasing tree cover to 30%, they were able to determine the number of deaths that could be prevented.

Of 6,700 premature deaths that were attributed to higher temperatures in cities during 2015, one-third (2,644) could have been prevented by upping urban tree cover to 30%, the study found.

Lead author Tamara Iungman of the Barcelona Institute for Global Health explained that “we already know that high temperatures in urban environments are associated with negative health outcomes, such as cardiorespiratory failure, hospital admission, and premature death”.

“This study is the largest of its kind and the first to specifically look at premature mortality caused by higher temperatures in cities and the number of deaths that could be prevented by increasing tree cover,” she said.

Our ultimate goal is to inform local policy and decision-makers about the benefits of strategically integrating green infrastructure into urban planning in order to promote more sustainable, resilient and healthy urban environments and contribute to climate change adaptation and mitigation.

“This is becoming increasingly urgent as Europe experiences more extreme temperature fluctuations caused by climate change; despite cold conditions currently causing more deaths in Europe, predictions based on current emissions reveal that heat-related illness and death will present a bigger burden to our health services over the next decade.”

Director of Urban Planning, Environment and Health at the institute and co-author Mark Nieuwenhuijsen added that the results “suggest large impacts on mortality due to hotter temperatures in cities, and that these impacts could be partially reduced by increasing the tree coverage to help cool urban environments”.

We encourage city planners and decision-makers to incorporate the urban green infrastructure adapted to each local setting whilst combining with other interventions to maximise the health benefits while promoting more sustainable and resilient cities, especially as we already know that green spaces can have additional health benefits such as reducing cardiovascular disease, dementia and poor mental health, improving cognitive functioning of children and the elderly, and improving the health of babies.”