What happened to Ozone Layer Depletion and the World's Ozone Hole?

Remember how we spent years worrying about the hole in the ozone layer? So how come the panic died down? Was it just an exaggerated phenomenon, or did we solve the global environmental problem? Before we answer these questions, let us first review what ozone layer depletion actually entails.

Introduction

Consisting of three oxygen atoms, ozone molecules form naturally in the upper atmosphere of our Earth. Though ozone makes up very little of our atmosphere, it plays a vital role in protecting all life on Earth. The ozone layer is often thought of as the Earth’s personal sunscreen, acting as a shield against the sun’s harmful ultraviolet radiation. The lack of such a protective layer would increase the rate of skin cancer, cataracts, and immune system disorders in humans. It can also seriously damage most animals, plants, and microbes, and further contribute to global warming.

So, imagine the rising anxiety when scientists discovered that we had ripped a hole in the ozone layer back in the early 1980s. The “hole” actually refers to a region over the Antarctic where the ozone layer had dramatically thinned. Although ozone is created and destroyed naturally in the atmosphere, man-made chemicals like chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs) and halogenated substances previously found in refrigerators, air-conditioners and aerosol sprays destroyed ozone at alarmingly high rates. These ozone-depleting substances (ODSs) remain in the atmosphere for a long time and continue to degrade the stratospheric ozone molecules. Considering how grave a threat ozone layer depletion was deemed to be, how did the problem essentially fall off the radar?

As the news of the discovery spread like wildfire, the world swiftly jumped into action. The adoption of the Montreal Protocol in 1987 marked a turning point in environmental history. Ratified by all 198 UN member states, the treaty’s main objective was to phase out ozone-depleting substances and work to repair the damage that had already been done. The success of this legislation has been unparalleled. Not only was the production and consumption of ozone-depleting substances brought to a halt, the treaty was able to efficiently reduce carbon emissions as well. Given that 35 years have passed since the treaty was first signed, it is important to look at how the situation has further developed.

The Current Situation

The ozone hole is still present today and forms over Antarctica in the springtime every year. The hole diminishes over the summer and reappears in the following spring as the cycle restarts. However, there is evidence to suggest that it is beginning to disappear and recover as predicted.

On October 5, the ozone hole reached its greatest size since 2015, measuring more than 26.4 million square kilometres (10 million square miles), larger than the size of Antarctica itself. And although the ozone hole peaked at a moderately large size in 2022, for the third consecutive year, experts note that it is still generally shrinking.

“The overall trend is improvement,” said NASA’s Goddard Space Flight Center’s chief Earth Scientist Paul Newman, “Over time, steady progress is being made, and the hole is getting smaller. We see some wavering as the weather changes and other factors make the numbers wiggle slightly from day to day and week to week. But overall, we see it decreasing through the past two decades.” Compared to the ozone holes in the late 1990s and early 2000s, the hole is far smaller in 2022. Furthermore, in early 2022, scientists from the National Oceanic and Atmospheric Administration (NOAA) discovered that the concentration of ozone-depleting substances in the stratosphere had decreased by just over 50%, returning to the levels seen in the 1980s. These trends point towards a promising future for the ozone layer. According to scientists, if we adhere to the objectives outlined in international accords like the Montreal Protocol, the hole may even revert to pre-1980 levels during the course of the next 50 years, or sometime between 2060 and 2070.

While ozone layer depletion has been considerably curbed, we are not out of the woods quite yet. It is true that the ozone hole is shrinking in size, but it is still recovering quite slowly. This is because many of the chemicals that have already been released are incredibly long-lasting –some persist in the atmosphere for up to a century – slowing down the ozone layer’s rate of recuperation.

The future is not without risks. Short-term ozone losses are often caused by large volcanic eruptions. Nitrous oxide, a potent greenhouse gas released from the use of fertilisers in agriculture, is also a severe ozone-depleting chemical. Recent studies have also found that chemical reactions between iodine and ozone are the second highest contributor to ozone layer depletion. Furthermore, global warming and climate change also negatively affect the ozone layer. According to a study, the Australian “Black Summer” bushfires along with other intense wildfires contributed to at least a 1% loss of the ozone layer. That is the amount recovered over the past decade as a result of the adoption of the Montreal Protocol. Another area of concern is the new ozone hole that has been detected over the tropics. It is seven times larger than the hole located over Antarctica and appears year-round, unlike the seasonal Antarctic ozone hole. Given that the tropics are home to about half of the world’s population, the tropical ozone hole may as well be another global environmental crisis. Though some doubts have been raised about these findings, such a claim only emphasizes the need to remain vigilant and comply with climate action legislation.

Conclusion

Ozone layer depletion and the Antarctic ozone hole pose a real threat to our planet. The reason it is not as talked about as before is because steps have been taken to limit the phenomenon. It was universally acknowledged that preserving the ozone layer was of utmost importance at the time. Regarded as the most successful piece of climate protection legislation, the Montreal Protocol addressed and dealt with the existential threat of ozone layer depletion and the results were remarkable. This emphasises how crucial it is to continuously monitor environmental factors, including CFCs, temperature, and biodiversity markers. If we do not keep an eye on them, we will not know if we are in trouble or not, and consequently, fail to take preventive action.

Despite the ozone hole's expansion this year, most experts concur that it is indeed on the mend. However, that does not mean that further climate action is not required. In fact, the creation of the ozone hole demonstrated how quickly human activity can damage the environment. While the Montreal Protocol does demonstrate that we can tackle catastrophic environmental problems, we must remain on the lookout for new risks and actively try to mitigate them.

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