World Ozone Day: Significance, Facts About Global Efforts To Preserve 'Fragile Shield Of Gas'

World Ozone Day, observed every Sept. 16, celebrates the decades of hard work in the efforts to preserve the all-important ozone layer.

The ozone layer is a "fragile shield of gas" that protects the Earth from harmful radiation from the sun, thereby helping to preserve life on the planet. However, human activities have damaged this protective shield to a great extent. With less of its protection from ultraviolet light, there could be more crop damage and higher rates of health conditions like skin cancer and cataracts.

World Ozone Day or the International Day for the Preservation of the Ozone Layer is commemorated to mark the decades of global ozone layer protection after scientists in the 1970s discovered that humans were making a hole in this protective layer. This led to the Vienna Convention, under which the Montreal Protocol aimed to phase out ozone-depleting substances such as those in refrigerators and air conditioners.

"The Montreal Protocol started life as a global agreement to protect the ozone layer, a job it has done well, making it one of the most successful environmental agreements to date," the United Nations (UN) noted.

Let's have a look at some important facts people need to know about the ozone layer and the efforts being made to protect it. (Courtesy: National Geographic, the UN Environment Programme and the European Commission)

The ozone concentration naturally fluctuates depending on conditions such as temperature, weather and even natural events like volcanic eruptions. They were generally stable when measurements began in 1957, but research revealed "signs of trouble" in the 1970s and 1980s.
The thinning of the ozone layer is most pronounced in the polar regions, particularly over Antarctica.
The ozone-depleting substances that humans have emitted can stay in the atmosphere for decades. This means its recovery is a "very slow, long process."
There have been signs of recovery in the ozone layer in the past decades. For instance, the mid-latitudes saw a 1 to 3% increase in upper stratosphere ozone per decade since 2000. The UN also confirmed in 2018 that the ozone layer is recovering.
The Montreal Protocol was ratified by all 197 UN member countries. Without it, the U.S. would have had 280 million more skin cancer cases, 1.5 million skin cancer deaths and 45 million cases of cataracts.
Efforts to protect the ozone have also assisted in slowing climate change by preventing 135 billion tons of carbon dioxide emissions. Moreover, most of the man-made ozone-depleting substances are also "potent" greenhouse gases whose warming effects can be up to 14,000 times stronger than carbon dioxide, so banning them also helped the fight against climate change.
According to NASA simulations, without the Montreal Protocol, the global ozone would have fallen so low that in 2065 that light-skinned people in the mid-latitudes would have a "perceptible sunburn" within just five to 10 minutes outside in the summer.
The ozone's "substantial" recovery from ozone-depleting substances may happen sometime around the middle of the century "assuming global compliance with the Montreal Protocol."