A groundbreaking study published in The Lancet Planetary Health reveals that increasing urban vegetation by 30% could prevent over 1 million heat-related deaths globally from 2000 to 2019. The study was led by Professor Yuming Guo from Monash University. It modeled the impact of greening urban areas on reducing heat exposur, which is a growing public health threat worsened by climate change.
The 20-year study examined the potential cooling effects of increasing urban vegetation in 11,534 urban areas worldwide. It found that increasing vegetation by 10%, 20%, or 30% would:
- Reduce the global population-weighted warm-season mean temperature by 0.08°C, 0.14°C, and 0.19°C, respectively.
- Prevent 0.86 million, 1.02 million, and 1.16 million deaths, accounting for 27.16%, 32.22%, and 36.66% of all heat-related deaths between 2000 and 2019.
GREENNESS: A VITAL STRATEGY TO COMBAT HEAT MORTALITY
The findings underscore the powerful role of urban greenness in mitigating the health impacts of heat exposure. According to Professor Guo, this study is the first to assess both the cooling and modifying effects of increased vegetation. It provides a more comprehensive understanding of its benefits in reducing heat-related deaths.
“Preserving and expanding greenness might be potential strategies to lower temperatures. These strategies could mitigate the health impacts of heat exposure,” said Professor Guo.
GLOBAL VARIATIONS IN HEAT-RELATED DEATHS AND THE COOLING POWER OF GREEN SPACES
The cooling effects of increasing urban vegetation varied across different climate regions. Areas in Southern Asia, Eastern Europe, and Eastern Asia saw the most significant reduction in heat-related deaths.
Urban vegetation impacts are particularly important as heat exposure continues to escalate due to climate change. Between 2000 and 2019, heat exposure was linked to 0.5 million deaths per year, accounting for 0.91% of global mortality. Projections suggest that in the most extreme global warming scenarios, heat-related deaths could rise to 16.7% in Southeast Asia by 2090-99.
HOW GREENNESS REDUCES HEAT-RELATED MORTALITY
Urban green spaces work to reduce heat in multiple ways. Greenness cools the environment through:
- Shading surfaces: Blocking direct sunlight.
- Deflecting solar radiation: Reducing the heat absorbed by buildings and streets.
- Evapotranspiration: The evaporation of water from plants, which promotes air convection, further cooling the surroundings.
These cooling effects lower the overall population heat exposure, directly reducing the mortality burden linked to extreme heat events.
GREENNESS AND HEALTH BEYOND TEMPERATURE
In addition to its cooling effects, greenness is emerging as a modifier of heat-related mortality risk. Studies suggest that urban vegetation may influence factors like mental health. It can also affect social engagement, physical activity, and air pollution. All of these contribute to a community’s vulnerability to heat.
Increasing urban vegetation can improve overall public health. It can reduce the societal impacts of extreme heat. This approach could be a multi-faceted solution to combat the increasing threats posed by climate change.
A GLOBAL CALL FOR GREENING URBAN SPACES
The research highlights the importance of greening urban areas as a climate adaptation strategy. As heat exposure rises with climate change, green spaces could offer an effective, cost-efficient way to protect public health, especially in densely populated urban areas.
THE PATH FORWARD FOR URBAN GREENING
The study emphasizes that expanding urban vegetation by just 30% could save over 1 million lives and prevent a significant proportion of heat-related deaths. This research provides compelling evidence for cities worldwide to invest in increasing urban greenness as a strategy for reducing heat exposure, improving public health, and combating the adverse effects of climate change.
As cities continue to face the impacts of climate change, integrating more green spaces into urban planning could be an essential step toward creating healthier, more resilient cities for future generations.