The impact of extreme heat climate on the sustainable development of urban economies

Purpose Extreme heat (EH) occurs frequently in China, severely hindering the sustainable development of the urban economy. Improving green economic efficiency (GEE) is key for sustainable economic development. This study aims to explore the influence of EH on GEE. Design/methodology/approach This article measured the annual GEE level using the superefficiency slacks-based measure (Super-SBM) model, including undesired outputs. The number of EH days in each city was measured using the relative threshold method. The bidirectional fixed effects model was adopted to explore the impact of EH on GEE. The authors verified the mitigation mechanism of aggregated positive externalities and innovatively constructed a temperature-adjacency spatial matrix to confirm the spatial spillover effect of EH on GEE. Findings The results indicate that EH negatively influences GEE and has a more pronounced adverse impact on GEE in nonclimate-adaptive pilot cities and regions east of the Hu Huanyong Line. Innovative talent agglomeration and industrial collaborative agglomeration can mitigate this negative impact, and their coupled and coordinated development can reduce the adverse effects of EH on GEE. Concerning the spatial effect, local EH has a positive spillover effect on surrounding cities’ GEE. Originality/value This study expands and supplements existing research and provides new insights for objectively assessing the economic consequences of EH. The authors offer scientific recommendations for cities to address extreme climates and enhance the economic green efficiency of Chinese cities.