The Antarctic ozone hole closed on December 1 after a rapid contraction in November, becoming the smallest in a decade and a testament to the Montreal Protocol’s success.
Seasonal Dynamics of the Ozone Hole
The ozone hole appears over the South Pole during austral winter and spring, from late June to early December. This year it developed in August and reached an average size for the period, but was smaller than in 2022‑23.
Rapid Contraction and Early Closure
By November the hole shrank swiftly and fully closed on December 1, the earliest closure in five years and one of the earliest in over 40 years of measurement.
Success of International Agreements
Global elimination of ozone‑depleting substances under the Montreal Protocol has produced a measurable decline in hole size, indicating progress toward full recovery.
Remaining Challenges and Long‑Term Outlook
Full ozone layer restoration will take several decades; estimates project a complete recovery by 2050‑2066. The shrinking, however, shows that international treaties are effective.
Broader Environmental Benefits
Reducing chlorine‑containing gases also curbed part of global warming, contributing roughly 0.5 °C of avoided temperature rise, alongside the primary carbon‑dioxide effect.