The emergence and de-emergence of CFC-induced stratospheric ozone depletion and its impact on surface climate of the Southern Hemisphere. ...

• Main Author: Robertson, Fergus
• Format: Article in Journal/Newspaper
• Language: English
• Published: University of Canterbury 2023
• Subjects: Antarctic; Antarc*
• Online Access: https://dx.doi.org/10.26021/14565; https://ir.canterbury.ac.nz/handle/10092/105470

Signal-to-noise (S/N) is a metric that has been previously used to diagnose the emergence of climate change, but has not been applied to stratospheric ozone and its projected recovery from CFCs through the 21st century. In this thesis, S/N ratios are calculated from data produced by chemistry-climate models to diagnose the emergence and “de-emergence” of CFC-induced stratospheric ozone depletion, and the effects of changes in ozone on the climate of the Southern Hemisphere. This was done as previous studies of ozone depletion use arbitrary return dates (e.g., return to 1980 levels) to diagnose recovery, which is not a statistically robust metric, and ignores ozone depletion that occurred prior to 1980. Overall, S/N calculations show that springtime Antarctic ozone depletion de-emerges significantly later (in 2085) than its 1980-return date (2060). Because increasing greenhouse gas concentrations through the 21st century are projected to lead to increases in ozone, the de-emergence of ozone depletion with and ...