Demand for air conditioning is set to surge by 2050

WHEN JOE BIDEN was a newly elected senator, he asked James Eastland, his fellow in Congress, to tell him the most significant thing that occurred during his long time in the chamber. “Air conditioning,” Mr Eastland replied. Summer in Washington is stifling, so in the past members of Congress departed by June. “Then we put in air conditioning, stayed year round, and ruined America,” he reportedly said, sardonically.

These days the main concern about air conditioning (AC) is its environmental cost. A report in 2018 by the International Energy Agency, a Paris-based energy think-tank, found that AC units and electric fans consumed nearly 10% of global electricity in 2016. Just 8% of the 2.8bn people living in the hottest parts of the world (places where the average daily temperature is higher than 25°C) owned AC units five years ago, but that proportion is expected to increase rapidly. Energy consumption by AC will rise too: the IEA expects it to triple by 2050. This will lead to increased emissions of carbon-dioxide and greenhouse gases such as hydrofluorocarbons, which are used as refrigerants in AC units and can leak into the atmosphere. The United Nations estimates that if hydrofluorocarbons are not phased out, they could cause temperatures to rise by up to an extra 0.4°C by 2100.