Where Has The Ozone Layer Hole Been All This Time?

Learn what destroyed the ozone layer and how the Montreal Protocol's prohibition on dangerous chemicals helped to repair it.

The ozone layer had a rapidly growing hole in it in the 1980s, which presented a major issue for the entire planet. If it kept expanding, skin cancer rates would soar, photosynthesis would be compromised, agricultural output would decline, and entire ecosystems would disintegrate. What transpired, then? Stephanie Honchell Smith demonstrated through extensive research how resolute international cooperation supported ozone layer restoration.

The ozone layer had a rapidly growing hole in it in the 1980s, which presented a major issue for the entire planet. What transpired, then? Does it still exist? Retrace our steps to the beginning. Although the Sun is necessary for life to exist on Earth, too much UV radiation can harm animal and plant DNA.

Thankfully, ozone molecules absorb around 98% of that energy scattered across the stratosphere, which undergo a constant process of breaking down and reforming, keeping a delicate balance. However, two chemists, Mario Molina and Sherwood Rowland, in the early 1970s, showed that compounds known as chlorofluorocarbons, or CFCs, may throw off this balance.

Three US-based firms created CFCs in the 1920s as refrigerator coolants. CFCs weren't toxic or combustible like other options, including ammonia or methyl chloride, so they wouldn't catch fire or release dangerous gas leaks. They also produced excellent foaming agents, fire retardants, and propellants. The use of CFCs quickly spread to many commonplace things, creating a multi-billion dollar business. CFCs are inert in the lower atmosphere and do not degrade or interact with other chemicals.

However, Molina and Rowland demonstrated that in the stratosphere, UV radiation breaks them apart, releasing chlorine atoms.

These then combine with ozone and react, depleting it more quickly than it can regenerate. Before reacting with another element to create a stable molecule, a single chlorine atom can destroy thousands of ozone molecules.

When the CFC industry realized they were in danger, they retaliated by attacking the scientists, even claiming they were KGB agents. Initial projections suggested that CFCs might lower ozone concentrations by 7% in 60 years. However, by the year 1985, it was evident that ozone depletion, particularly over Antarctica, was occurring considerably more quickly.

Here, the unusual structure of Antarctic clouds and the exceptionally low temperatures hastened the depletion of ozone. Every spring, researchers in Antarctica have observed a significant decrease in the amount of ozone in the atmosphere. Satellite data showed the substantial scale of these losses, and chemical analyses proved beyond a doubt that CFCs were to blame.

Soon after, NASA created graphics that attracted attention from the general public and were televised all over the world. Skin cancer incidence would increase dramatically if ozone depletion persisted.

Plants, including rice, wheat, and corn, would be less productive and more prone to disease as a result of the decreased photosynthesis. The world's agricultural output would decline, and entire ecosystems would disintegrate.

However, many politicians prioritize short-term economic issues over long-term ones conflicted over what to do. President Ronald Reagan of the United States and Margaret Thatcher of the United Kingdom were two unexpected partners in the campaign to outlaw CFCs. Reagan, who had undergone treatment for skin cancer, and Thatcher, who was educated as a scientist, realized the necessity for quick action despite their overall aversion to government regulation. The US and UK were among the countries that spearheaded efforts for a global ban on CFCs, along with Canada, Norway, Sweden, and Finland.

Reps signed the Montreal Protocol in 1987, which mandated the quick phase-out of CFCs and established a fund to help the countries of the Global South acquire inexpensive, non-ozone-depleting alternatives.

Later, every nation on Earth ratified it, making it the only pact in history to do so. Molina, Rowland, and Paul Crutzen, a Dutch collaborator, shared the 1995 Nobel Prize in Chemistry.

The ozone hole started to get smaller when the use of CFCs decreased, and it's expected to close up completely by 2070. But the battle is not yet won. Since CFCs are strong greenhouse gases, the ban was good for the environment, and hydrofluorocarbons, or HFCs, which took their place are just as bad. Even though they are typically less powerful than CFCs, HFCs nevertheless retain more heat than carbon dioxide and are a factor in global warming.

The Kigali Amendment, which stipulates an 85% reduction in global HFCs by 2047, was introduced to the Montreal Protocol in 2016 to address this issue. By the end of the century, this might save up to 0.5°C of global warming. The Montreal Protocol serves as a model for the determined international cooperation necessary to address the serious threat that climate change poses in the modern era. What will it take for us to reunite once more is the question?