UN: Earth's ozone layer on the path to recovery

A group of UN experts has announced that the Earth's ozone layer will recover by the year 2060. Dr. Dmitry Zamolodchikov, a biologist and academic mentor of the "Low-Carbon Development Management" program, discussed the impact of the Montreal Protocol on mitigating the consequences of climate change and explained the concept of stratospheric aerosol injection.

At the 103rd Annual Meeting of the American Meteorological Society, the Scientific Assessment Panel of the Montreal Protocol on Substances that Deplete the Ozone Layer presented the Ozone Depletion Assessment Report.

Scientists believe that with the continuation of the current policy - a phased-out elimination of nearly 99% of banned ozone-depleting substances - the ozone layer will recover to 1980 levels (pre-ozone hole era) by approximately 2066 over Antarctica, by 2045 over the Arctic, and by 2040 over other regions of the world.

For the first time in the report, scientists also highlighted the potential impact of stratospheric aerosol injection on the ozone layer - the deliberate addition of aerosols into the stratosphere. The expert panel warns that the unintended consequences of SAI "could also affect stratospheric temperatures, circulation, ozone production and depletion rates, and its transport."

Dmitry Zamolodchikov

The issue of global climate warming has come to the forefront in the last decade, somewhat overshadowing other global environmental problems. In the 1980s, the degradation of the Earth's ozone layer was considered the most significant environmental issue. The main cause of this degradation was the production and active use of various halogen-containing gases (such as chlorofluorocarbons and halons) as refrigerants. When these gases entered the ozone layer, they released chlorine, which acted as a catalyst in transforming ozone (trioxygen) into ordinary diatomic oxygen. The degradation of the ozone layer manifested as the expansion of so-called ozone holes over polar regions of the Earth and a decrease in stratospheric ozone concentration in other regions of the planet.

Coordinated international actions were taken to address the issue of ozone layer degradation. The Vienna Convention for the Protection of the Ozone Layer was adopted in 1985, followed by the Montreal Protocol in 1987, which established a schedule for reducing the production of ozone-depleting substances. As a result of these agreements, the production and use of ozone-depleting substances significantly decreased, and the ozone layer began to recover. Due to the successful resolution of the ozone layer degradation problem, it faded from the public's attention. However, efforts to monitor and control this issue continue. For instance, every four years, UNEP publishes a report on the state of the ozone layer, with the latest report released in 2022. It notes that the recovery of the ozone layer is progressing successfully, and full recovery is projected by 2060. Furthermore, measures to reduce the production of hydrofluorocarbons prescribed by amendments to the Montreal Protocol are expected to reduce global warming by 0.3-0.5°C by 2100, as these gases have a potent greenhouse effect.

Additionally, the report examines the potential impact of stratospheric aerosol injection (SAI) on the ozone layer. SAI involves the release of aerosol particles into the stratosphere from aircraft with the aim of enhancing the atmosphere's reflective properties and counteracting global temperature rise. It is noted that SAI may affect the rates of ozone formation and depletion, as well as its transport in the atmosphere. There is a high likelihood of unpredictable consequences for the functioning of the planet's biosphere associated with SAI, as indicated in various other scientific studies.