- In 1913, Charles Fabry and Henri Buisson discovered that the ozone collects in a layer in the stratosphere.
- Montreal Protocol was signed in 1987, and the day is observed as World Ozone Day.
- By the mid-21st century, a complete recovery of the ozone layer is expected.
- Montreal Protocol is estimated to have avoided 2.3 million skin cancer deaths and 63 million cataracts in the US alone.
- The substances that deplete ozone layer also possess very high global warming potential.
By now, every person reading this article would know that the ozone layer present in the Earth’s stratosphere protects us from the sun’s harmful ultraviolet radiation that can cause sunburn, skin cancer and eye damage to humans. And, discovering a hole in this protective umbrella back in 1985 prompted humanity to wage war against the ozone-depleting substances (ODS) like the chlorofluorocarbons (CFCs). But, what is the ozone hole, how did we discover it, and how did we address it? The story is truly inspiring!
The ‘hole’ story
The story goes back to 1776 when a French chemist named Antoine Lavoisier first proved that oxygen is indeed a chemical element. Following this discovery, several experiments were conducted with oxygen, and one particular experiment of passing electricity through oxygen gave up some intriguing results. The experiment produced a strange slightly pungent-smelling chemical that, in the 1830s, a German-Swiss chemist Friedrich Schönbein named as ‘ozone’, meaning ‘to smell’ in Greek.
In 1913, French scientists Charles Fabry and Henri Buisson discovered that the ozone collects in a layer in the stratosphere, roughly 18 km above Earth’s surface. While the science behind the ozone layer is a century old, it was only by the 1970s that scientists started to notice the impact of CFCs on this roof of life. But, even the most alarming studies in that decade did not predict significant impact, with a projected decline in ozone layer below 10%.
Shockingly, in 1985, Joe Farman, Brian Gardiner and Jonathan Shanklin reported a large decrease in stratospheric ozone levels over the Antarctic. Their research showed that within a decade, the ozone layer had lost one-third of its thickness over the south polar region—what came to be known as the Antarctic Ozone Hole.
Road to recovery
In March 1985, world leaders met in Austria the Protection of the Ozone Layer and the Vienna convention was signed, calling for more research on the ozone layer. Still, it contained no legally binding goals for ODS reductions. However, the ozone hole story caught the attention of the public who feared skin cancer, cataract and many ecological consequences of ozone depletion.
Fueled by public outrage and fears of drastic depletion, 24 nations signed the legally-binding Montreal Protocol in 1987 to limit the use of CFCs. The Protocol entered into force in 1989 and is now ratified by 197 countries across the globe, making it one of the most successful international agreements to date.
September 16, the day when Montreal Protocol was signed in 1987, is celebrated as International Day for the Preservation of the Ozone Layer since 1994. Now, we have learnt a lot more about the ozone over the past three decades, and know that many parts of the world experience seasonal fluctuation in the ozone layer. Every inch of the layer is being tracked regularly now, and the phasing-out of CFCs has helped it’s recovery to a large extent.
“There are few global agreements as successful as the Vienna Convention for the Protection of the Ozone Layer. Today, on World Ozone Day, we celebrate 35 years of this convention, which was the first step in fixing the hole in the planet’s ozone layer,” says António Guterres, Secretary-General of the United Nations.
As per the US Environmental Protection Agency estimates, the implementation of the Montreal Protocol could avoid 443 million cases of skin cancer, 2.3 million skin cancer deaths, and 63 million cataracts in the United States alone. By the mid-21st century, a complete recovery of the ozone layer is expected.
Link to climate change
Climate change, global warming and ozone depletion are all linked intricately as every change in atmosphere influences each of these phenomena. Due to global warming, the temperature of the stratosphere is falling gradually, leading to the formation of more stratospheric clouds over Antarctica, and hence delaying the recovery of the Ozone Hole. In other places, however, the cooling is likely to thicken the ozone layer further.
Moreover, a depleted ozone layer results in increased warming due to higher influx of solar radiation. Also, the substances that deplete ozone possess very high global warming potential, hence leading to increased atmospheric warming. Therefore, climate action and ozone prevention have to go hand in hand.
“The work of the Montreal Protocol is not over. Through the Protocol’s Kigali Amendment, the international community is finding alternatives for coolants that contribute to the growing menace of climate disruption. If fully implemented, the Kigali Amendment can prevent 0.4 degrees Celsius of global warming,” says Guterres.
As humanity recovers a devastating pandemic, the path ahead is to take lessons and inspiration from our battle against ozone depletion and build back a better future.
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