13 December 2018

The Signature of Ozone Depletion in Recent Antarctic Precipitation Change: A Study with the Community Earth System Model

Ozone depletion increases Antarctic snowfall.

Spatial pattern of ozone-forced Antarctic snowfall change
Science

Stratospheric ozone depletion, also known as the ozone hole, has started in the 1970s and, despite a slow recovery, thanks to the Montréal protocol, will continue well into the 21st century. Previous studies have shown that ozone depletion not only enhances ultraviolet radiation at the surface but also affects weather patterns and sea ice on the Southern Ocean, north of the Antarctic ice sheet. However, a key question still remains: What is the impact of ozone depletion on Antarctic climate, and particularly precipitation? This is important, because the changes in Antarctic precipitation regulates the ice sheet's contribution to sea level rise.

Impact

In this work, we compare two series of climate model simulations, one with an ozone hole prescribed and one without, to suggest that the ozone hole leads to a substantial increase in Antarctic precipitation. This increase is driven by a shift in weather patterns that bring snowfall onto the ice sheet. The total estimated increase of precipitation on the Antarctic ice sheet is of the same order of magnitude than its current mass loss, suggesting that Antarctic mass loss during the period 1992–2005 would have been roughly twice as much without the ozone hole.

Summary

Antarctic stratospheric ozone depletion has caused a significant increase in Antarctic snowfall, according to climate model simulations.  Ozone recovery, as is expected in the future, will remove this mitigating effect and thereby cause an additional acceleration of sea level rise in the future.

Contact
Jeremy Fyke
Associated Engineering Group of Companies
Publications
Lenaerts, J, J Fyke, and B Medley.  2018.  "The Signature of Ozone Depletion in Recent Antarctic Precipitation Change: A Study With the Community Earth System Model."  Geophysical Research Letters 45(23): 12931-12939.  https://doi.org/10.1029/2018GL078608.