Reduction of urban heat island and associated greenhouse gas emissions

The reduction of urban heat island (UHI) and carbon emission is of great importance for thermal environment of urban residential areas. This paper aimed to establish a method to analyze the effect of different underlying surface layouts on the reduction of heat island intensity and carbon emission. Taking Tianjin, China, as a case study area, a computational fluid dynamics (CFD) model, satellite-based remote sensing retrieval technology, and orthogonal experimental design were performed to investigate and quantify the performance of mitigation strategies (i.e., urban green space or water body, cool/high reflectivity pavement, and reflective roofs and facades) on UHI. The results indicated that urban green space is the most natural and effective mitigation strategy, while the widespread application of cool/high reflectivity materials is suggested as a mitigation strategy for building height more than 10 m above the ground. Application of urban water body is the next preferred strategy for air at 1.5 m pedestrian level. Green roofs, rainwater gardens, and permeable brick pavements are also more feasible in high-density cities for mitigating the UHI effect. The above mitigation and adaptation strategies of community scale can be acted on UHI and as a global urban climate change response.