NASA and NOAA report that the Antarctic ozone hole in 2026 was the seventh largest in area during 48 years of monitoring. Scientists said atmospheric conditions favored ozone depletion, but The Hole was not as deep as some larger holes recorded in previous decades. The agencies say the ozone layer remains on a path toward long-term recovery.
During the peak depletion season, from Sept. 7 to Oct. 13, the hole covered an average of about 9.6 million square miles (25 million square kilometers). Its largest one-day extent was recorded on Sept. 18, at 10.5 million square miles (27.1 million square kilometers). The largest ozone hole since monitoring began reached its maximum extent in September 2000.
A powerful, unusually large polar vortex contributed to the 2026 hole’s size. Weak planetary-scale weather systems in August and September did less than usual to disrupt the vortex, keeping its strongest winds farther from the pole and expanding the area with conditions suitable for ozone depletion. The vortex creates the cold conditions that allow chlorine and bromine from human-made compounds to break down stratospheric ozone.
Despite its broad extent, the hole was not as deep as the record holes of earlier decades. NOAA balloon measurements over the South Pole recorded a yearly low of 105 Dobson units on Oct. 17. The lowest value measured there was 92 Dobson units, in October 2006.
NASA and NOAA said reductions in ozone-depleting substances under the 1987 Montreal Protocol continue to support ozone recovery. Antarctic stratospheric chlorine from these substances has fallen by about one-third compared with levels in the 1980s. Because compounds such as chlorofluorocarbons can persist in the atmosphere and leak from older products and landfills, scientists estimate that the ozone hole will recover by the 2070s.
NASA and NOAA used satellite, balloon and ground-based observations to track the ozone layer. The satellite data included measurements from NASA’s Aura, NOAA-20 and NOAA-21, and the Suomi National Polar-orbiting Partnership satellite, jointly operated by NASA and NOAA.
Sources: NASA Breaking News.