Antarctic Ozone Hole Shrinks to Fifth-Smallest Size in Over Three Decades

The ozone hole over Antarctica has shrunk to its fifth-smallest size in more than three decades, NASA and the National Oceanic and Atmospheric Administration confirmed in 2025. The steady recovery is a direct result of the Montreal Protocol — an international environmental treaty signed in 1987 that phased out the production of chlorofluorocarbons (CFCs) and other ozone-depleting chemicals. A weaker polar vortex in 2025 also contributed to the smaller hole.

The ozone layer serves as Earth's shield against harmful ultraviolet radiation, and its depletion was linked to increased rates of skin cancer, cataracts, and damage to crops and marine ecosystems. "Since peaking around the year 2000, levels of ozone-depleting substances in the Antarctic stratosphere have declined by about a third relative to pre-ozone-hole levels," said NOAA senior scientist Stephen Montzka. The ozone story is often cited as one of humanity's greatest environmental success stories — proof that when nations act together on scientific evidence, they can reverse even planetary-scale environmental damage. Full recovery of the ozone layer is projected by roughly 2066.

“The steady recovery is a direct result of the Montreal Protocol — an international environmental treaty signed in 1987 that phased out the production of chlorofluorocarbons (CFCs) and other ozone-depleting chemicals.”