This illustration shows the size and shape of the ozone hole over the South Pole on the day of its 2025 maximum extent. Moderate ozone losses (in orange) are visible amid areas of more potent ozone losses (in red). Scientists describe the ozone “hole” as the area in which ozone concentrations drop below the historical threshold of 220 Dobson Units. Credit: NASA Earth Observatory image by Lauren Dauphin created with data courtesy of NASA Ozone Watch and GEOS-5 data from the Global Modeling and