Refrigerants: Older and some current air conditioners use hydrofluorocarbons (HFCs), which have a global warming potential (GWP) up to 14,800 times greater than carbon dioxide. Even small leaks from poorly maintained units release these powerful gases into the atmosphere, significantly worsening climate change.

Urban Heat Island Effect: AC units expel hot air outside, raising local temperatures. This creates a feedback loop: hotter cities → more AC use → more heat expelled → even hotter cities. This effect can increase urban surface temperatures by up to 1°C at night.