Ozone Depletion Reaches Unprecedented Levels
Is the Ozone layer under threat again? Recent satellite data has suggested that the Antarctic ozone hole has expanded to an alarming size. It’s now one of the largest ever recorded, spanning an area equivalent to three times that of Brazil. This significant development has raised concerns among environmentalists and scientists alike.
How is this even possible? You could ask. According to a United Nations Assessment, Earth’s ozone layer is gradually repairing itself and, at this rate, the gap over Antarctica should be completely sealed in approximately 43 years.
What is the cause of this ?
Scientists are not sure what could be the cause of this but have speculated that that there might be a connection to the underwater volcanic eruption in Tonga from January 2022. According to their satellite based measurements, the eruption injected 0.4 Tg (Teragram) of SO₂ (Sulfur dioxide) into the stratosphere. The Volcanic SO2 got converted into sulfate aerosols which quickly contributed to changes in stratospheric Ozone at mid-low latitudes through a variety of chemical processes. Aerosols through physical and chemical mechanisms led to a decrease in Ozone layer from July to December 2022. However, scientists caution that the exact impact of the eruption on the hole is still the subject of ongoing research.
Volcanic eruptions release various gases into the atmosphere, the most relevant for ozone depletion being SO₂ .Once in the stratosphere, SO₂ can convert to sulfate aerosols. These aerosols provide surfaces on which reactions can take place, leading to the production or destruction of ozone. They can also influence global climate by reflecting sunlight. Similar to the Tonga volcanic eruption in 1981 One of the most significant eruptions concerning atmospheric impacts happened. The eruption of Mount Pinatubo in the Philippines. The eruption released around 20 million tonnes of SO2 into the stratosphere. This led to the creation of aerosol particles which, in combination with human-made CFCs (Choloroflurocarbon), intensified the destruction of ozone, leading to a larger and deeper Antarctic ozone hole in 1992 and 1993. Additionally, the sulfate aerosols also had a cooling effect on the Earth’s climate for a few years after the eruption.
It is safe to say that the recent discovery of a larger Ozone hole over Antarctica is due to a natural occurrence than a direct result of human activities. The world solved the problem of Ozone depletion in the past, it shouldn't be a roadblock if we were to encounter the problem again.
References:
- Lu, Jinpeng, et al. “Stratospheric Aerosol and Ozone Responses to the Hunga Tonga‐Hunga Ha’apai Volcanic Eruption.” Geophysical Research Letters, vol. 50, no. 4, American Geophysical Union (AGU), Feb. 2023. Crossref, https://doi.org/10.1029/2022gl102315.
- NASA Ozone Watch: 2023 Antarctic OMPS and MERRA-2 Ozone. ozonewatch.gsfc.nasa.gov/meteorology/SH.html.
