Increasing urban vegetation can save over 1.1 mn lives from heat-related deaths: Study
Amid increasing global warming and heat-related deaths worldwide, a new study has shown that expanding urban vegetation cover by 30 per cent could save over one-third of all deaths caused due to heat, saving up to 1.16 million lives globally.
Researchers from Monash University in Australia showed that increasing vegetation levels by 10 per cent, 20 per cent, and 30 per cent would decrease the global population-weighted warm-season mean temperature by 0.08 degrees Celsius, 0.14 degrees Celsius, and 0.19 degrees Celsius, respectively.
It can also prevent 0.86, 1.02, and 1.16 million deaths, respectively.
While increasing greenness has been proposed as a heat-related death mitigation strategy, 'this is the first modelling study to estimate both the cooling and modifying effects of greenness, providing a more comprehensive assessment of its benefits in mitigating heat-related mortality,' said Professor Yuming Guo from the varsity.
The findings, published in the journal The Lancet Planetary Health, are based on a 20-year modelling study of the impact of increasing greenness in more than 11,000 urban areas from 2000 to 2019.
Urban areas in Southern Asia, Eastern Europe, and Eastern Asia were found to have the greatest reduction in heat-related deaths.
'These findings indicate that preserving and expanding greenness might be potential strategies to lower temperature and mitigate the health impacts of heat exposure,' Guo said.
Heat exposure is a major public health threat and is increasing due to climate change. Between 2000-2019, heat exposure was associated with 0.5 million deaths per year, accounting for 0.91 per cent of global mortality.
According to Guo, estimates of heat-related deaths are projected to range from 2.5 per cent in North Europe to 16.7 per cent in South-East Asia during 2090-99, 'under the most extreme global warming scenarios.'
Studies show that greenness has a cooling effect on temperature, via shading surfaces, deflecting radiation from the sun, and evapotranspiration (evaporation from both the ground and plants) which promotes air convection.
This, in turn, cools the ambient temperature leading to a decrease in population heat exposure, thereby reducing the heat-related mortality burden.
In addition, greenness could also modify other related factors such as mental health, social engagement, physical activity, and air pollution, the researchers said.
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