Deaths caused by soaring summer temperatures could be reduced by planting more trees, research published in The Lancet suggests.
Cutting-edge modelling of 93 European cities by an international team indicates that heat-related deaths could be cut by 39.5% if cities doubled their typical tree cover, from just under 15% currently to 30%.
🌍The study results, obtained with data from 93 European cities, highlight the substantial benefits of planting more trees in cities to attenuate the impact of #ClimateChange. #ClimateCrisis #ClimateAction pic.twitter.com/8uTf7avf6p— ISGlobal (@ISGLOBALorg) February 1, 2023
From June to August 2015, the cities looked at experienced average temperatures 1.5oC warmer than the surrounding countryside. Higher temperatures are more likely to occur in cities with little vegetation, high population density, and impermeable surfaces for buildings and roads, such as asphalt. The combination of these factors can lead to a phenomenon known as “urban heat islands.”
This is becoming increasingly urgent as Europe experiences more extreme temperature fluctuations caused by climate change. We already know that high temperatures in urban environments are associated with negative health outcomes, such as cardiorespiratory failure, hospital admission, and premature death.Tamara Iungman, author at the Barcelona Institute for Global Health
Heat-related illness and fatalities are predicted to become more problematic for strained health services over the next 10 years than cold temperatures, but “more sustainable, resilient and healthy” cities are achievable, according to the researchers, who found that increased tree cover could have prevented 2644 deaths in 2015. Wider benefits of access to trees and green space include reduced cardiovascular disease and dementia, as well as improved mental health.
Mark Nieuwenhuijsen, who co-authored the study, explained that the recommendation of 30% tree coverage had been chosen as it is a common target among countries working on the issue.
Tree coverage tends to be lower in the very cities that suffer the highest temperatures in south and eastern Europe. While Oslo boasts 34% tree cover and London 15%. Lisbon has just 3.6%. The highest number of excess deaths due to heat in 2015 occurred in Cluj-Napoca in Romania, with 7% tree cover.
The lead author, Tamara Iungman, from the #Barcelona Institute for Global Health, said: “This is becoming increasingly urgent as #Europe experiences more extreme temperature fluctuations caused by #climatechange.” pic.twitter.com/WhpTL9QdOk— Al Mayadeen English (@MayadeenEnglish) February 2, 2023
All the cities studied had enough room to plant more trees without destroying existing infrastructure according to Nieuwenhuijsen, though he suggested “car-dominated” cities should replace heat-absorbing asphalt roads with trees. A special mention went to the EU’s 3bn trees plan, and the UK’s Environmental Improvement Plan to bring green space within 15-minutes of every home, in addition to the importance of even tree distribution between affluent and low income neighbourhoods.
Professor Yadvinder Malhi, an Oxford ecosystem specialist not involved in the study, agreed: “Urban trees bring many co-benefits beyond climate change adaptation: many studies show just seeing and smelling trees benefit health and wellbeing, as well as enhancing urban biodiversity. But most tree cover is found in wealthy towns and neighbourhoods, so enhancing urban tree cover can reduce this inequity and particularly reduce the high vulnerability of poorer neighbourhoods to climate change.”