Projection of trade-offs of commercial air conditioning: Increasing carbon emission and reducing heat exposure

The growing air conditioning used to reduce heat-related risks has raised widespread concerns on its carbon emissions, potentially posing additional challenges to climate change mitigation efforts. Recognizing and comprehending these trade-offs is helpful for the government in formulating comprehensive climate change strategies. However, it remains unclear how the trade-offs between increasing carbon emissions and reducing heat risks due to future air conditioning use will evolve in China's climate change context. This study conducted a modeling study and first estimated its trade-offs from 2020 to 2100 at the provincial level by comparing its economic benefits of reducing heat-related labor productivity loss and increasing carbon emission at the provincial level in China. The findings indicate substantial economic benefits from reducing heat-related labor productivity loss and carbon emissions resulting from air conditioning use. The cumulative benefit from 2020 to 2100 is projected to reach US$ 604.1 billion under SSP245 scenario, with a twofold increase in carbon emissions from air conditioning use compared with 2020, about 1095.4 million tons in 2100, assuming no changes in electricity structure and energy efficiency. The average carbon emission for reducing one million US dollars in GDP loss are projected to be 38,670.1 tons/million US$ under SSP126 scenario, 24,716.7 tons/million US$ under SSP245 scenario, and 9137.2 tons/million US$ under SSP585 scenario. The trade-offs exhibit regional variations, with lower carbon emissions per unit of benefit concentrated in populous and high-income regions, such as Guangdong, Shandong, Zhejiang, etc., and higher carbon emissions per unit of benefit concentrated in low-income regions located in low latitude, including Hainan, Guizhou, Guangxi, and Sichuan. Therefore, regions are encouraged to develop tailored measures to address these trade-offs.