The heat wave that we suffered this summer in Spain caused thousands of people to die in our country, since part of the excess deaths registered were attributed to high temperatures. This is not the first time something like this has happened, and experts warn that this will happen more and more frequently due to global warming associated with climate change.
It is therefore urgent to adopt measures that help prevent the health risks associated with climate change. Now, a new study has found that a third of the premature deaths that were attributed to excessive temperatures in European cities during the summer of 2015 could have been avoided by increasing the number of trees in these cities by 30% and that, if In fact, tree cover dropped an average of 0.4 degrees in summer temperatures.
In cities, temperatures are higher than in the surrounding countryside, which is often known as ‘urban heat islands’, a temperature difference that is due to the modification of landscapes by human activity that has eliminated the vegetation, added asphalt to the ground, and built buildings with materials that absorb and trap heat. Greenhouse gas emissions contribute to climate change and global warming, with temperatures in cities expected to continue to rise and heat waves to become more intense and prolonged, requiring cities to adapt to improve the health of its population.
“The results suggest large mortality impacts due to higher temperatures in cities, which could be reduced by increasing tree cover to help cool urban environments.”
“We already know that high temperatures in urban settings are associated with negative health outcomes, such as cardiorespiratory failure, hospitalization, and premature death. This study is the largest of its kind and the first to look specifically at premature mortality caused by higher temperatures in cities and the number of deaths that could be prevented by increasing tree cover,” said lead author Tamara Iungman of the Institute. of Global Health of Barcelona (ISGlobal).
The researcher adds that the final objective of this work is to provide information that shows the benefits of “strategically integrating green infrastructure in urban planning to promote more sustainable, resilient and healthy urban environments and contribute to the adaptation and mitigation of climate change”. something that he considers urgent due to the increasingly extreme temperature fluctuations that are experienced in Europe. Although cold weather currently causes more deaths on the continent, heat-related illnesses and deaths are expected to place a greater burden on healthcare systems in the coming decade.
Green spaces and trees help cool cities
The study authors estimated death rates for those aged 20 and older residing in 93 European cities between June and August 2015, including 57 million people. Data on rural and urban daily temperatures were collected for each city, and they first estimated premature mortality by simulating a hypothetical scenario without an urban heat island. Second, they estimated how much temperatures would drop if tree cover were increased to 30%, as well as how many deaths could be prevented.
The results have been published in The Lancet and reveal that in that period of time the temperature in the cities was on average 1.5ºC higher and that 6,700 premature deaths in the cities could be attributed to the high temperatures, which constitutes 4, 3% of the total summer mortality and 1.8% of the mortality throughout the year. One in three of these deaths (2,644 in total) could have been prevented with a 30% increase in tree cover, which would have lessened the heat. This corresponds to 39.5% of all deaths attributable to higher urban temperatures, 1.8% of all summer deaths, and 0.4% of year-round deaths.
These findings support the idea that urban trees provide significant environmental and public health benefits, but the researchers acknowledge that planting more trees in cities must be combined with other measures aimed at maximizing urban temperature reduction, such as changing ground surface materials so that the temperature drops at night, and they are aware that meeting the 30% tree cover target can be a great challenge for some cities by design. Currently, the average tree cover of cities in Europe is 14.9%.
“Our results suggest large impacts on mortality due to higher temperatures in cities, and that these impacts could be partially reduced by increasing tree cover to help cool urban environments. We encourage urban planners and decision makers to incorporate urban green infrastructure tailored to each local environment while combining it with other interventions to maximize health benefits and promote more sustainable and resilient cities, especially as we already know that green spaces may have additional health benefits, such as reducing cardiovascular disease, dementia and poor mental health, improving cognitive functioning in children and the elderly, and improving the health of babies,” explained study co-author Mark Nieuwenhuijsen, Director of Urban Planning, Environment and Health at the Barcelona Institute for Global Health.
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