Emergence of healing in the Antarctic ozone layer

TLDR

The Montreal Protocol phased out ozone‑depleting chlorofluorocarbons, and chemical, dynamical, and temperature changes are expected to drive a healing of the polar ozone layer. September healing since 2000 is evidenced by rising ozone column amounts, altered vertical ozone profiles, and reduced ozone‑hole area. Observations and models show that healing of the Antarctic ozone layer began in September, though volcanic eruptions, notably the 2015 Calbuco eruption, have intermittently disrupted this trend.

Abstract

Industrial chlorofluorocarbons that cause ozone depletion have been phased out under the Montreal Protocol. A chemically driven increase in polar ozone (or "healing") is expected in response to this historic agreement. Observations and model calculations together indicate that healing of the Antarctic ozone layer has now begun to occur during the month of September. Fingerprints of September healing since 2000 include (i) increases in ozone column amounts, (ii) changes in the vertical profile of ozone concentration, and (iii) decreases in the areal extent of the ozone hole. Along with chemistry, dynamical and temperature changes have contributed to the healing but could represent feedbacks to chemistry. Volcanic eruptions have episodically interfered with healing, particularly during 2015, when a record October ozone hole occurred after the Calbuco eruption.