Links between stratospheric ozone depletion and changes in surface climate were first found in research studies in the early 2000s, based on both observations and models. While increasing greenhouse gases (such as carbon dioxide, methane, and nitrous oxide) are the primary drivers of global climate change, the Antarctic ozone hole, which reoccurs every spring since the early 1980s, was shown to contribute indirectly to observed changes in Southern Hemisphere surface climate during summer due to its effects on atmospheric circulation.
The severe springtime ozone depletion over the Antarctic leads to a strong cooling of the polar lower stratosphere persisting into early summer. This increases the temperature contrast between the tropics and the polar region, which strengthens stratospheric winds. For reasons that are not well understood but are consistently reproduced in models, this leads to a poleward shift of tropospheric circulation features including the tropical Hadley cell (which determines the location of the subtropical dry zones) and the midlatitude jet (which is associated with weather systems). There is some evidence from both models and observations that subtropical and midlatitude summer precipitation patterns have been affected by these changes. The observed wind changes over the Southern Ocean have also likely driven significant changes in ocean currents. Model studies suggest that long-lived greenhouse gases that cause climate change exacerbate this shift in summertime Southern Hemisphere tropospheric circulation, but that ozone depletion has been the dominant contributor to the changes over the last few decades.
During the 21st century, ozone recovery is expected to lead to the reversal of the above climate impacts driven by the ozone hole. This reversal will result in some cancellation of future Southern Hemisphere circulation changes driven by greenhouse gas increases. The extent of such a cancellation depends on the greenhouse gas emissions assumed in future climate projections. The Southern Hemisphere surface climate response to ozone depletion in other seasons is weaker. No such links between ozone depletion and regional climate change have been observed for the Northern Hemisphere.