Project No: 26309618
Title: Quantifying the relative contributions of anthropogenic climate change and urban growth to human thermal comfort in China
PI: Prof. Im, Eun Soon
The most relevant anthropogenic activities that can significantly modify the Earth’s climate system are greenhouse gas (GHG) emissions and land-use/land-cover (LULC) changes. While increased GHG emissions perturb the global energy balance, LULC changes due to urban growth alter the surface energy partitioning and the water cycle at the regional to local scale through surface-atmosphere interactions. Despite their different physical processes, both GHG emissions and urban expansion are considered as important contributors to global and local warming trends. In this regard, China is a representative region with rising concerns about anthropogenic warming, particularly along the heavily populated eastern coast with its rapid development. Studies on detection and attribution of recent climate changes evidenced the significant increase in the frequency and intensity of heat waves in China due to global warming. Observational and modelling studies also support the urban expansion’s role in exacerbating the severity of heat waves. Although the impacts of climate change and urbanization on the present climate are well documented, most climate projections have not appropriately considered future urban growth-induced LULC changes, leading to a potential underestimation of the risk of heat-related extremes. The proposed project will be the first attempt to quantify the relative contributions of anthropogenic climate change and urban growth on human thermal comfort in two vast urban agglomerations of China. An unprecedented level of dynamically downscaled climate projections will be produced within a state-of-the-art experimental framework in terms of multiple global climate models, multiple regional climate models, and multiple scenarios of both future GHG emissions and future urban growth. The factor separation method will be applied to various subsets of massive simulations, which facilitates separating the contributions of the two individual factors (GHG emissions vs. urban growth) as well as their synergetic effects on temperature, humidity, and the related thermal comfort. Not only conventional heat stress indices that measure the combined effects of temperature and humidity, but also thermophysiological indices that account for metabolic heat production depending on labor intensity, will be considered to integrate the perception of the human body’s heat strain in an outdoor working environment. This project will strengthen our understanding of the urban-atmosphere interactions under global warming conditions, with important implications for the mitigation and adaptation strategies to alleviate the negative impacts of anthropogenic warming on human thermal comfort.