Rising Air-Conditioning Use Intensifies Global Warming

Global warming and socio-economic development are together prompting a surge in the use of air-conditioning (AC). Yet the technology that delivers thermal comfort also emits large quantities of greenhouse gases (GHG), exacerbating climate change. We quantify global AC-related GHGs and associated warming impact under five climate scenarios, separating the contributions of global warming and socio-economic development. In a middle-of-the-road scenario (SSP245), cumulative AC-related emissions reach 113.3 GtCO₂eq between 2010 and 2050, increasing global-mean temperature by 0.05 °C (0.03 °C-0.07 °C), with only about 8.3% to climate-driven cooling demand. Income inequalities exacerbate disparities in AC use, substantially limiting access to cooling in lower-income regions. While rising incomes reduce this inequality, they increase emissions: income-driven AC growth adds 14-146 GtCO₂eq and a further 0.003-0.05 °C of warming by 2050, even under SSP119. These results highlight the need for a rapid low-carbon cooling transition that balances total warming impacts with equitable cooling access.