ENVIRONMENT

The Hole We Repaired

1985 CE

History · Contemporary · Holocene · Meghalayan

In 1985, British scientists announced that springtime ozone over Antarctica was collapsing: a hole in the layer that shields life from ultraviolet light, opened by chlorofluorocarbons from spray cans and refrigerators. Two years later, the Montreal Protocol began phasing the chemicals out, every country on Earth eventually signing. By 2016, measurement and modelling agreed: the September ozone layer had begun to heal, humanity's first deliberate repair of a planetary system.

Why it matters

The ozone hole is the proof, cited in every climate negotiation since, that global environmental action can work: a planetary threat detected by patient monitoring, attributed by chemistry, and reversed by treaty within a decade of discovery. It is also a warning about luck, had industry chosen bromine instead of chlorine, the damage would have been far worse before anyone looked. The sky can be broken, and mended.

Dating & uncertainty

The British Antarctic Survey reported the springtime collapse of Antarctic ozone in 1985, from ground measurements begun decades earlier; the Montreal Protocol followed in 1987 and phased out chlorofluorocarbons worldwide. By 2016, September measurements and models agreed that healing had begun, fingerprinted in ozone column, profile and hole area, with volcanic setbacks along the way.

Sources

1. Farman, Gardiner & Shanklin (1985), Nature · Large losses of total ozone in Antarctica reveal seasonal ClOx/NOx interactiondoi:10.1038/315207a0
2. Solomon et al. (2016), Science · Emergence of healing in the Antarctic ozone layerdoi:10.1126/science.aae0061
3. United Nations Environment Programme · The Montreal Protocol on Substances that Deplete the Ozone Layer. Institutional source: UNEP Ozone Secretariat, accessed 2026-08-30.

Our species’ history as one day

23:59:4811.2 s before midnight

if the 315,000 years of Homo sapiens were compressed into a single day