Forty years ago this month, scientists reported that human activities had punctured Earth’s protective ozone layer. What happened next offers a masterclass in international science-diplomacy.

NOAA and NASA report that the 2025 ozone hole over Antarctica was far smaller and shorter-lived than usual. Falling chlorine levels and a weaker polar vortex helped limit ozone loss this season. These findings add to decades of evidence showing...

Latest status of ozone

The Antarctic ozone hole reached its largest area in two decades during September 2026, covering over 27 million square kilometres. This unprecedented size was preceded by early warning signs observed in May 2026, when scientists detected changes in atmospheric circulation patterns. The ozone hole's growth was driven by a strong polar vortex and unusually cold temperatures over Antarctica, creating ideal conditions for ozone depletion. While the 2026 ozone hole is the second-largest recorded for September, it has not yet reached the extreme depths seen in previous record years. The Montreal Protocol, which has successfully phased out ozone-depleting substances since its inception in 1987, continues to show positive results, with stratospheric levels of these chemicals dropping by approximately one-third since their peak around 2000. The 2026 ozone hole began forming earlier than usual in August, with low stratospheric temperatures accelerating its development. By September, it had rapidly expanded to 27.4 million square kilometres, surpassing all but two previous records. Scientists predict the hole will persist through October and November, potentially ranking among the top ten most severe ozone holes in recorded history. This year's event follows a pattern of increasingly severe ozone depletion since 2020, with factors including the 2019-20 Australian wildfires and the 2021 La Soufrière volcanic eruption contributing to worsened ozone depletion in previous years. The ozone hole significantly impacts Southern Hemisphere weather patterns, influencing the Southern Annular Mode which affects wind and precipitation patterns across New Zealand and Australia. While the ozone layer is projected to fully recover before 2090, recent trends suggest longer-lasting ozone holes may become more common, potentially altering the timeline for complete recovery. The ongoing research by scientists at the University of Otago and Earth Sciences New Zealand continues to improve understanding of the complex relationship between atmospheric dynamics and ozone depletion.

The Antarctic ozone hole was discovered in 1985, when scientists observed a severe depletion in the Earth’s protective layer of stratospheric ozone. Industrial chemicals known as chlorofluorocarbons (CFCs), then widely used as refrigerants, propellants, foam-blowing agents, and solvents, were at the root of the ozone depletion. After concerted global effort to phase out the use of CFCs, ozone today is recovering, especially in the Antarctic. The discovery of the ozone hole was possible thanks, in part, to the measurement tools that were available at the time. Advances in those tools, along with satellites and other monitoring technologies, have since allowed scientists to track ozone’s recovery. But what if today’s tech was available much earlier? Would scientists have been able to spot even earlier signs of human-induced ozone depletion? And if so, when would those first signs have popped up, and where? MIT scientists now have some answers. The team, led by atmospheric chemist Susan Solomon, has carried out a thought experiment in which they consider a hypothetical world where today’s atmospheric monitoring capabilities were available throughout the last century. In this scenario, they simulated the atmosphere’s chemistry through history and discovered not only when the earliest sign of ozone depletion...

The ozone layer over Antarctica, damaged by air pollution decades ago, has fortunately been recovering in recent years. Scientists have observed gradual ozone restoration since the 2000s, but now, one study all but confirms that this positive trend is a...