{
  "id": 9662758,
  "title": "September’s ozone hole was the biggest in 20 years. The warning signs appeared months ago",
  "url": "https://urgent.news/2026/09/25/septembers-ozone-hole-was-the-biggest-in-20-years-the-warning-signs",
  "topic": "science",
  "section": "Science",
  "published": "2026-09-25T00:13:47.000Z",
  "source": {
    "name": "The Conversation AU",
    "slug": "the-conversation-au",
    "url": "https://theconversation.com/septembers-ozone-hole-was-the-biggest-in-20-years-the-warning-signs-appeared-months-ago-292457"
  },
  "original_language": "en",
  "account": "September witnessed the largest Antarctic ozone hole in 20 years, covering an area of over 27 million square kilometres, according to observations. Signs of this massive ozone depletion had emerged months earlier. Scientists first predicted a severe ozone hole in May 2026, noticing changes in atmospheric circulation. A strong polar vortex and exceptionally cold temperatures over the South Pole were driving the early formation and size of the hole. However, the Montreal Protocol, a global treaty aimed at protecting the ozone layer by phasing out ozone-depleting substances, continues to be effective. While the area of this year's ozone hole has not reached the depths of past large ozone holes, it has started growing earlier than average in August and rapidly expanded from the beginning of September. The 2026 ozone hole area surpassed 27 million square kilometres, only previously broken in 2000 and 2015. The ozone hole forms within the stratospheric polar vortex, a strong wind pattern surrounding Antarctica in winter. Low temperatures inside the vortex lead to the formation of polar stratospheric clouds, which facilitate chemical reactions that activate ozone-depleting gases. The duration of the ozone hole depends on how well isolated the air is within the polar vortex, with a cold and robust vortex resulting in a longer-lasting hole. Despite chemical healing occurring through the reduction of ozone-depleting gases since the 1987 signing of the Montreal Protocol, atmospheric dynamics can still prime the vortex, leading to larger, deeper, and longer-lasting ozone holes. Early predictions for September 2026 were confirmed, and the hole is expected to persist into October and November. This follows a series of large and long-lasting Antarctic ozone holes from 2020 to 2023, possibly linked to factors such as smoke from Australian wildfires, aerosols from the 2021 La Soufrière eruption, and the 2022 eruption of the Hunga Tonga–Hunga Haʻapai submarine volcano. The 2020s have seen an unusual decade for ozone recovery. While a severe ozone hole in 2026 is not entirely unexpected, recent work suggests that atmospheric dynamics significantly exacerbated this year's ozone hole. The 2020s have been a unique decade for ozone recovery, with the Antarctic ozone hole projected to reach full recovery before 2090. However, recent changes in global atmospheric dynamics may lead to longer-lived ozone holes, potentially affecting weather patterns in the Southern Hemisphere, including Aotearoa New Zealand and Australia.",
  "summary": "This spring’s ozone hole is likely to be among the top ten most severe of all time, bringing weather changes to New Zealand and Australia.",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}