RESEARCH SUMMARY

The Cooling Effect of Urban Green Spaces and the Associated Health Benefits: Who, Where, and to What Extent Do They Benefit?

By Jie Cao

Jie Cao is a postdoctoral researcher at the State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China. Cao’s research focuses on the ecological effects of urbanization, particularly the synergistic impacts of climate change and urbanization on urban heat environments. She adopts a socio-ecological systems perspective, exploring population and spatial disparities in environmental exposure, and seeks to investigate the potential of nature-based solutions in improving both the environment and environmental equity. Her current work examines the spatial-temporal heterogeneity of temperature and its effects on human health, as well as the cooling effects and health benefits of urban trees at the intra-urban scale. She holds a BE in Environmental Engineering from Shandong University, and a PhD in Urban Ecology from the University of Science and Technology of China.

As cities around the world continue to grow, urban heat island (UHI) effects have become a critical issue, exacerbated by climate change. These effects lead to elevated temperatures in urban areas compared to their rural surroundings, increasing heat stress on vulnerable populations. Urban green spaces, such as parks, trees, and green roofs, are known to mitigate these heat islands by providing cooling benefits through shade, evapotranspiration, and overall reduction in ambient temperatures. However, the cooling effects of urban green spaces and their potential to improve human health are not uniform across cities or even within a city. This research investigates how the cooling efficiency of urban green spaces varies across different urban contexts and examines the resulting health benefits, with particular focus on how these impacts can reduce heat-related morbidity and mortality.

The core idea of this study is that the cooling effects of green spaces do not necessarily result in direct health benefits. Only when the cooling impact of green spaces overlaps with the health risks of the population, both in time and space, can significant health benefits be observed. Existing research indicates that urban heat health risks fluctuate over time and space, and are linked to factors such as the spatiotemporal distribution of urban temperatures, the spatial patterns of exposed populations, and the vulnerability and adaptive capacity of these populations. High-risk heat zones typically feature higher average temperatures, more dense buildings, fewer green spaces, and greater concentrations of vulnerable groups. These areas are also often the most challenging in terms of increasing green space coverage or where the cooling efficiency of green spaces is limited. Especially during extreme heat events, the intensity of heat stress continues to rise, but the cooling effects of green spaces may be diminished, making it difficult for their health benefits to be fully realized. How can we integrate knowledge from urban science, ecology, and epidemiology to establish a pathway connecting green spaces, temperature, and health in order to assess its health benefits and identify the influencing factors, ultimately revealing the contribution of green space cooling functions to public health? This is the question this study seeks to answer.

To address the research question, this study employs a multidisciplinary approach. First, spatial analysis is used to assess the variation in cooling effects of green spaces across different urban zones, integrating remote sensing, meteorological data, and socio-economic indicators. Next, statistical analysis is conducted to explore the relationship between heat exposure and health risks among different population subgroups, examining the influence of population exposure, vulnerability, and adaptive capacity on health outcomes. A meta-analysis is then applied to synthesize relevant literature and field data, evaluating the overall health benefits of green space cooling and identifying key influencing factors. Finally, a green space-temperature-health pathway is established to reveal the specific contribution of green space cooling to public health.

This research will offer valuable insights into the role of urban green spaces in climate change adaptation and public health improvement. By understanding how green spaces mitigate the urban heat island effect and reduce heat-related health risks, the study will provide evidence-based recommendations for urban planners, policymakers, and health professionals. These recommendations will aim to optimize green space design and urban policies, particularly in vulnerable communities, ensuring that green infrastructure can play a key role in building resilient, healthy cities in the face of climate change. The findings will contribute to sustainable urban planning practices and the promotion of public health through the strategic use of nature-based solutions.