Trees in Cities Prevent Heat-Related Deaths
A new study has found that planting trees in urban areas can prevent mortality caused by increased temperatures.
The increase of global warming and the expansion of built environments in cities negatively impact human health. Cities record higher temperatures than surrounding suburbs or countryside due to the urban heat island effect. The urban heat island effect happens when natural land cover is replaced with concentrations of pavement, buildings and other surfaces that absorb and retain heat. The rise in temperatures increases energy costs, air pollution levels, heat-related illnesses and mortality.
A new study has shown that planting more trees in urban areas will lower temperatures and could help reduce deaths directly linked to hot weather and heat waves. Trees have a cooling effect in built-up areas, providing shade and moisture and deflecting the sun’s rays. Trees also cool the environment by absorbing carbon dioxide.
Trees in Cities Prevent Heat-Related Deaths. The researchers looked at the impact on 93 European countries and found that increasing tree cover by 30 percent would decrease temperatures by 0.4 degrees Celsius. Of the 6,700 premature deaths resulting from higher temperatures in 93 European cities during 2015, one-third could have been prevented with the presence of more trees.
They also found that only 15 percent of European urban environments are covered by some foliage. The countries that would benefit the most from additional tree cover are South and eastern Europe, where summer temperatures are the highest and tree coverage tends to be lower. The study stresses the need to take environmental action, especially as summer temperatures reach record highs in response to climate change.
Some cities have already taken on the task of planting more trees. Madrid, Spain, is building a 75-kilometre urban forest with a million new trees. The project will sequester 175 000 tons of carbon dioxide annually and reduce temperatures within the city. To keep cooler and fight climate change, Paris, France, plans to plant 170 000 new trees by 2026. And London plans to ensure that half of the city will be green by 2050 and that the tree canopy cover will increase by a tenth.
In addition to preventing deaths and reducing air temperatures, planting trees in urban areas has many other health benefits. Green spaces and trees can help reduce cardiovascular diseases, dementia and poor mental health. A study in Germany found that living within 100 metres of a tree can reduce the need for antidepressant drugs. Trees in urban areas can also improve the cognitive functioning of children and the elderly. Living near parks or green spaces can also mean having more exercise and leisure time, which may result in fewer health risks.
Planting trees to reduce the effects of climate change and prevent deaths seems like a no-brainer. Hopefully, this study will make local policymakers aware of the importance of tree cover in urban areas and will help create more sustainable and climate-resilient cities.