A 2026 study led by Jian Guan at MIT indicates that ozone depletion could have been detected as early as 1957 if modern monitoring capabilities had been in place. The research, published in PNAS, utilized climate models to simulate historical atmospheric conditions and ozone chemistry.

The study found that an industrial solvent, carbon tetrachloride, played a larger role in early ozone depletion than chlorofluorocarbons (CFCs). Ice core records from 1950 show that carbon tetrachloride was three to four times more prevalent than initial CFC levels during that period. Model simulations indicated that carbon tetrachloride accounted for half to two-thirds of the ozone-depleting chlorine in the upper stratosphere in 1957.

These model simulations suggested that ozone depletion would have been detectable with 95 percent statistical confidence in the upper stratosphere over the tropics around 1957. If modern scientific infrastructure had been available in 1950, depletion in the lower stratosphere, including over Antarctica, would have been detectable by 1976.

The scientists incorporated various factors into their climate model, including ozone chemistry, historical greenhouse gas emissions, ozone-depleting pollution, and natural events such as volcanic eruptions. Ozone formation results from the interaction of sunlight and oxygen gas, and its levels are known to be sensitive to the 11-year cycle in solar activity. Emissions from volcanic eruptions can also cause chemical changes within the ozone system.

The discovery of CFCs' ability to destroy atmospheric ozone occurred in 1974. The seasonal ozone hole over Antarctica was discovered in 1985, leading to an international agreement to phase out CFCs signed in 1987. Modern tools for ozone measurement include a satellite, which has been in orbit since 2004 and continues to measure ozone at multiple heights in the stratosphere, despite being past its intended lifespan.