Overview

• The 2024 hole was smaller than 2020–2023 and below the 1990–2020 mean, with a maximum ozone mass deficit of 46.1 million tonnes recorded.
• WMO says decades of controls under the Vienna Convention and Montreal Protocol have cut production and use of regulated ozone‑depleting substances by more than 99 percent.
• Models project a return to roughly 1980 ozone levels by mid‑century: about 2040 for most regions, around 2045 over the Arctic, and near 2066 over Antarctica.
• Scientists caution that year‑to‑year changes reflect natural atmospheric variability, so a single season’s size should not be over‑interpreted.
• Some replacement gases are powerful climate warmers targeted by the Kigali framework, with reductions expected to avert roughly 0.5°C of future warming.