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Arctic ozone reaches record high in positive step for climate

Earth's ozone layer holes over polar regions, where the stratospheric ozone level is significantly depleted, have been a prevalent feature of climate change news in recent decades. Anthropogenic-sourced chlorofluorocarbons (CFCs) are the primary cause, released from household items such as coolants in fridges, air conditioners and spray cans. Restricting their use has been and remains paramount to ozone hole recovery as they have multi-decadal lifetimes in the atmosphere.

Policies to address ozone depletion, such as the 1987 international agreement of the Montreal Protocol, aim to stop the production and consumption of ozone-depleting substances in order to heal these ozone holes by 2045 and 2066 over the Arctic and Antarctic respectively. As such, since early 2000, levels of stratospheric ozone-depleting inorganic chlorine and bromine in the Arctic have declined, albeit rather slowly.

Amidst this bleak forecast, research published in Geophysical Research Letters has hinted at a brighter future to come. Dr. Paul Newman, Chief Scientist for Earth Scientists at NASA's Goddard Space Flight Center, and colleagues identified March 2024 as a record high month for Arctic ozone since the 1970s, following a period of overall increase through winter 2023 to 2024.

Above-average ozone levels continued to persist through September 2024. This is significant as, previously, spring has been associated with ozone depletion when high CFC levels were coincident with large, cold, rotating low-pressure meteorological systems, known as polar vortices.

The research team highlight the significance of this research as preliminary evidence that CFC levels are now declining, in order to allow the ozone layer to begin its lengthy recovery. Dr. Newman said, "Ozone is the Earth's natural sunscreen. Increased ozone is a positive story, since it's good for the environment and encouraging news that the global Montreal Protocol agreement is producing positive results."