This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: As temperatures broke records this summer, sales of air-conditioning units soared. But this technology can compound climate change.
Air conditioners pump a gas, known as a refrigerant, around a sealed loop to carry heat out of (and sometimes into) the room. Some of that gas inevitably leaks out over the unit's working life and when it is scrapped. Unfortunately, many refrigerants are potent greenhouse gases.
Worldwide, leaked refrigerants account for roughly one-third of the climate impact of cooling, with electricity used to run the equipment responsible for the rest. Air-conditioning units have different labels. One that has recently been installed in a house or office probably says "R-32," a type of hydrofluorocarbon (HFC).
Older units often say "R-410A," which is a blend of HFCs. Kilogram for kilogram, R-410A traps around 2,000 times more heat than carbon dioxide. R-32 is still a potent greenhouse gas, but only about a third as warming as R-410A.
Scientists have been concerned about refrigerants for decades. But if you wind the clock back to the 1970s and 1980s, they were more worried about the fact that the refrigerants used then harmed the ozone layer than about their impact on the climate. Around this time, researchers discovered that the most widely used refrigerants back then, chlorofluorocarbons (CFCs), were damaging the stratospheric ozone that shields us from the ultraviolet radiation that causes skin cancer.
Following the discovery of a "hole" in the ozone layer over Antarctica, nations agreed to sign a landmark environmental treaty known as the Montreal Protocol in 1987. This protocol and its later amendments phased out the CFCs but allowed, as an interim measure, compounds called hydrochlorofluorocarbons (HCFCs) that were less harmful to the ozone layer. During the 1990s, HCFCs began to be replaced by HFCs, which don't deplete ozone at all.
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