Why don’t we hear about us destroying the ozone layer anymore?

ozone layer
The ozone layer has a hole above Antarctica. Credit: NASA Earth Observatory (via Flickr)

By Mia Becker-Hansen | Head of Science and Technology

In the 1985, discovered a hole the size of North America in the ozone layer above Antarctica caused by humanity, and it was on track to be completely destroyed by 2050. Comments about the destruction of the ozone layer even appeared in now famous sitcoms and films at the time and thereafter. So, what happened to the ozone layer since then? Did we cure it?

The ozone layer is a ‘belt’ around the Earth made up of gaseous molecules, above the Troposphere but below the Stratosphere. It protects all living things of Earth by absorbing two types of Ultraviolet radiation from the Sun, UV-B and UV-C. Without it, ecosystems would collapse, skin cancer rates would skyrocket, and life on Earth would be very different. 

Scientists travelled to Antarctica to study the cause of this 40% depletion in the ozone layer which was getting worse every year. They found that the problem was being caused by chorine from a man-made compound called Chlorofluorocarbons (CFCs). CFCs are not harmful on the ground, but once they float up to the Stratosphere the Sun breaks them down into chlorine. They bind with ozone to make oxygen and chlorine monoxide. Then, the loose oxygen atoms bump the chlorine atom out, freeing it to destroy more chlorine molecules, which causes a chain reaction. Chlorofluorocarbons have a long lifespan of around 50 to 150 years in our atmosphere, the build-up of this loss of ozone in the ozone layer increases exponentially.

At this time, humanity used a great deal of CFCs. They were used in the manufacture of aerosol sprays, blowing agents for foams and packing materials, as solvents, and as refrigerants. The US at this time had already moved away from CFCs in aerosol cans, but most of the world had not.

This growing threat led to some of the fastest collective action on climate the world has ever seen.

It was easy to find substitutions to CFCs and implement the switch. Scientists engaged with the public about the devastating issue, which in turn put pressure on leaders around the world to act. This resulted in the creation of the Montreal Protocol. It recognised that “world-wide emissions of certain substances can significantly deplete and otherwise modify the ozone layer in a manner that is likely to result in adverse effects on human health and the environment”. 

It listed control measures to reduce ozone depleting substances in a series of steps. This included help for developing countries who need alternative technology and substituting products. Every singly country signed the protocol. This makes it the only universal treaty to ever be ratified. It is still the most successful environmental agreement in human history.

Soon after the signing of the Montreal protocol in 1989, the world’s largest CFC producer, Du Pont, began to phase them out. The consumption of ozone-depleting substances, including CFCs, plummeted. Today, more than thirty years after the Montreal protocol was signed, the ozone hole has stopped growing and is now shrinking. By 2065 it is expected to have recovered completely.

However, after the CFC ban, we began using Hydrofluorocarbons (HFCs). These don’t deplete the ozone layer, but they are a potent greenhouse gas that contributes to climate change, the fastest growing one. In 2016, the Montreal Protocol was amended to include HFCs, so they are now being phased out too. Nevertheless, they are only one part of a larger issue.

Our most challenging environmental problem, climate change, is still in need of big solutions. The almost destruction of our ozone layer proved that we are capable of coming together to help our planet. Let us hope that this can happen once more to save our world from its biggest threat yet.

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