Antarctic ozone hole effect on climate sensitivity

A new study made an interesting retrospective on a problem that our generation is facing, and that is already bringing dramatic consequences

by Lorenzo Ciotti
Antarctic ozone hole effect on climate sensitivity

"Since about 1980, the tropical Pacific has been anomalously cold, while the broader tropics have warmed. This has caused anomalous weather in midlatitudes as well as a reduction in the apparent sensitivity of the climate associated with enhanced low-cloud abundance over the cooler waters of the eastern tropical Pacific.

Recent modeling work has shown that cooler temperatures over the Southern Ocean around Antarctica can lead to cooler temperatures over the eastern tropical Pacific. Here we suggest that surface wind anomalies associated with the Antarctic ozone hole can cause cooler temperatures over the Southern Ocean that extend into the tropics.

We use the short-term variability of the Southern Annular Mode of zonal wind variability to show an association between surface zonal wind variations over the Southern Ocean, cooling over the Southern Ocean, and cooling in the eastern tropical Pacific.

This suggests that the cooling of the eastern tropical Pacific may be associated with the onset of the Antarctic ozone hole." This was explained by the authors of the study The Antarctic ozone hole and the pattern effect on climate sensitivity, published on the Proceedings of the National Academy of Sciences of the United States of America, who made this interesting retrospective on a problem that our generation is facing, and that is already bringing dramatic consequences.

The ozone layer is a fundamental screen for the interception of lethal radiations for life on Earth, and its formation mainly takes place in the stratosphere at the most irradiated tropical latitudes, while the global circulation then tends to accumulate it more at high latitudes and at the poles.

The mechanism of hole formation is different from the mid-latitude depletion of the ozone layer, but both phenomena are based on the fact that halogens, mainly chlorine and bromine, catalyze ozone-destructive reactions. The responsible compounds appear to be mainly due to human action.

Stratospheric phenomena should not be confused with the fact that ozone is an energetic oxidant and for living beings it is a highly poisonous gas, therefore harmful if present at low altitudes, where it can form as it is one of the gaseous contaminants of atmospheric pollution, a pollutant secondary forming later, in general, by combustion, with sterilizing characteristics towards all forms of life.

Instead, at high altitudes, it is an essential gas for the maintenance of life on Earth, since it absorbs harmful ultraviolet radiations, and this layer can thin, but cannot completely disappear, given that, after the ozone layer, the UV rays would radiate the oxygen present in the next atmospheric layer going to recreate more ozone.