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Imagine a world where skin cancer is as common as the flu. Where a few minutes in the sun unprotected could be a matter of life and death. This is not something out of a dystopian movie, but a very real possibility if the ozone layer fails us — or rather we fail the ozone layer.
In the late 1970s, scientists discovered disturbing changes in the atmosphere. The ozone layer was thinning, with a significant loss particularly over Antarctica. The news solidified in 1985, when the British Antarctic Survey published a report showing what would later be known as the “ozone hole.”
The ozone layer is the Earth’s natural sunscreen that shields us against the harmful UV rays from the sun. Solar UV rays hold the potential to completely convert our green and blue earth into a barren planet. UV radiation is also a major agent aiding the rising development of skin cancers. A study estimated that a 10% decline in ozone levels could lead to a 16-32% increase in the incidence rates of skin cancer.
Ozone Depletion: The Suspected Threats
In 1974, F. Sherwood Rowland and Mario J. Molina discovered the key chemical associated with ozone depletion (and won a Nobel Prize for it!) Chlorofluorocarbons (CFCs), once staples in refrigeration and air conditioning, when released into the atmosphere catalyse the destruction of ozone molecules. Later in the decade, other chemicals such as halons, carbon tetrachloride and methyl chloroform (substances commonly used in fire extinguishers and industrial solvents) were also identified to have contributed to ozone depletion.
Some substances used in fire extinguishers linked to ozone depletion | Photo by David Henry
Early success in ozone layer recovery
The Montreal Protocol
In response to the alarming scientific evidence of ozone depletion, the global community – 197 countries, came together to take decisive actions. The Montreal Protocol on Substances that Deplete the Ozone Layer was adopted in 1987. This landmark treaty aimed to phase out and phase down the production and consumption of ozone-depleting substances. The protocol established a clear timeline for reducing and eventually eliminating the use of key ODS.
Some sSecretary Kerry Delivers Remarks About the Montreal Protocol in Kigali
Following the implementation of the Montreal Protocol, scientists began to observe a gradual recovery of the ozone layer. By the early 2000s, data indicated that the ozone hole over Antarctica was stabilising and even showing signs of shrinking.
Ozone recovery stalls: The hole expands again
For years, we believed the ozone layer was on a steady path to recovery. But, recent reports show that the ozone hole has expanded yet again. The European Environment Agency revealed that in 2023, the ozone hole over the Southern Hemisphere reached a maximum area of 26.1 million km² at the end of September, making it the sixth largest ozone hole recorded since 1979.
Source: Copernicus Atmosphere Monitoring Service (CAMS)
What’s causing this setback?
Some scientists point out that six of the last nine years have had exceptionally low ozone amounts and extremely large ozone holes. There are several lines of speculations for what may be the reason behind these setbacks.
One guess is that climate change may be brewing something new in the atmosphere which is reversing some of the ozone layer recovery.
Volcanic eruptions have also been linked to ozone depletion. The huge eruption of the Hunga-Tonga-Hunga-Ha’apai volcano in 2022 is believed to have affected the ozone levels around that time. The combination of wildfire and volcanic aerosols may likely be contributing to the setbacks in ozone recovery.
One scientist pointed out that It’s important to note that the ozone hole varies a lot from year to year. Hence, only long-term trends should be used to provide a proper representation of the overall state of the ozone layer.
Nonetheless, it doesn’t change the fact that the ozone hole lies gaping open which is enough cause for concerns that are growing within the scientific community. There is a strong need to identify, address, and eliminate the root causes behind this ozone layer depletion or there will be delirious consequences.
Originally written by Aditi Rawat
Updated by Nishita Singh
