A new study from an international team of scientists, including University of Maryland Professor Ross Salawitch, shows that extremely low winter temperatures high in the atmosphere over the arctic are becoming more frequent and more extreme because of climate patterns associated with global warming. The study also shows that those extreme low temperatures are causing reactions among chemicals humans pumped into the air decades ago, leading to greater ozone losses.
The new findings call into question the commonly held assumption that ozone loss would grind to a halt in just a few decades following the 2010 global ban on the production of ozone depleting chemicals called chlorofluorocarbons (CFCs) and halons.
The study—which was jointly conducted by UMD, the Alfred Wegener Institute’s Helmholtz Centre for Polar and Marine Research, and the Finnish Meteorological Institute—appeared in the journal Nature Communications on June 23, 2021.
“We’re in a kind of race between the slow and steady decline in CFCs, which take 50 to 100 years to go away, and climate change, which is causing polar vortex temperature extremes to become colder at a rapid pace,” said Ross Salawitch, who is a professor in the UMD Department of Atmospheric and Oceanic Science, the Department of Chemistry and Biochemistry, and the Earth System Science Interdisciplinary Center. “The increasingly cold temperatures create conditions that promote ozone depletion by CFCs. So, even though these compounds are slowly going away, Arctic ozone depletion is on the rise as the climate changes.”