The global ban on ozone-depleting substances was a triumph of common-sense action. But what if the problem was spotted earlier?

In 1974, chlorofluorocarbons (CFCs)—common in aerosol cans—were found to destroy ozone. Bans soon followed. Yet, years before CFCs rose to prominence, carbon tetrachloride, a decades-old industrial solvent, was already impacting the ozone layer.

Carbon tetrachloride began its journey into the atmosphere around 1950, with levels peaking at three to four times higher than initial CFC levels. Detecting this impact, however, remains challenging due to natural variations in ozone levels. Sunlight and oxygen interactions, volcanic emissions, and altitude-specific changes all contribute to these fluctuations.

Today's scientific tools might have provided clearer insights earlier. Yet, the swift international response in 1987 highlights a commendable example of environmental cooperation. The Antarctic ozone “hole” discovery expedited this process, leading to the Montreal Protocol—a significant step towards protecting our atmosphere.

Reflecting on past and present, could we have acted sooner? Or is our current reaction truly groundbreaking?