Prof. GUO Hai, Management Committee Member of the Research Institute for Land and Space (RILS), Member of the Research Institute for Sustainable Urban Development (RISUD) and Professor in the Department of Civil and Environmental Engineering, together with global researchers, has conducted a first-of-its-kind study on the effectiveness of green-blue-grey infrastructure (GBGI) in cooling urban heat across various regions. The study findings have been published in the international interdisciplinary journal The Innovation.
The study revealed regional and city-specific variations in the effectiveness of GBGI in mitigating urban heat. In Europe, Asia, North America and Australia, the overall cooling effect of GBGI reaches 18.9°C, 17.7°C, 12°C and 9.63°C, respectively. In addition, the implementation of green and blue infrastructure has proven to be highly effective in lowering air temperatures globally. Green infrastructure regulates urban heat through evaporation, transpiration, shading and thermal insulation, while blue infrastructure absorbs heat and cools the surrounding area through evaporation.
The study also demonstrated that various GBGI features noticeably mitigate urban heat in Mainland Chinese cities. The most effective means of cooling include botanical gardens, wetlands, green walls and attenuation ponds, which provide temperature reductions of up to 10°C, 9.27°C, 8°C and 7°C, respectively.
Although the cooling effect ranges are generally similar in the north and south of China, variability was observed within regions. For example, in Beijing, botanical gardens reduce the temperature by up to 10°C, compared to only 2.7°C in Shaanxi province. In Hong Kong, parks, green roofs and golf courses were found to play substantial roles in urban cooling, resulting in temperature reductions of 4.9°C, 4.9°C and 4.2°C, respectively.
