The ozone hole problem was unintentionally caused by a chemist in late 1920. His name was Thomas Midgley and he produced a nontoxic compound that improved refrigeration, chlorofluorocarbon. It is commonly known as CFC. At sea level, these compounds are relatively unreactive so they were put to use. They were also used as propellants in spray cans and as solvents for cleaning greasy residues. They were used a lot.

In 1970 scientists finally found out that CFCs break down at high altitudes because of UV light. A chlorine atom then reacts with ozone and creates chlorine monoxide and oxygen. The chlorine monoxide reacts with ozone and creates chlorine and oxygen. It is a chain reaction that destroys ozone. CFCs are removed from the atmosphere very slowly so they can damage the ozone decades after they have been released.

The widespread use of CFCs created the ozone hole. It is not a literal hole, rather it is a place where as much as two-thirds of ozone is missing. It is also not a single hole, many holes cover a specific area. The missing ozone is a big issue because the ozone layer protects us from harmful UV light.

As much as 29 kilometres have been stretched out across the skies over Antarctica. It causes big issues for people living in Australia and New Zealand who are warned every year to not stay in the sun too long. That is because the ozone hole occasionally stretches from the South Pole towards middle latitudes.

The problem was first noticed in the year 1985. The scientist finally convinced politicians across the world in the year 1987 that something must be done about this issue. They signed the Montreal Protocol on Substances that Deplete the Ozone. It is the United Nations’ most successful treaty, many experts believe. Thanks to the treaty chlorine were phased out of refrigeration and scientists developed better alternatives.

But the problem is far from over. As we have established before, CFCs stay in the atmosphere for decades. The chemicals released decades ago are estimated to break down in 50-100 years. The worst ozone depletion actually accrued 15 years after the treaty was signed.

But there is also some good news. The CFCs levels in the upper and lower atmosphere peaked in the year 2000 and have been slowly describing since.

Even though we are not realizing CFCs the situation is still not over. Arctic ozone levels hit an all-time low in the year 2011 due to bad weather. They are now also researching how global warming is influencing the ozone.

There is no clear way how we can help with the issue. But there is an important lesson to be learned from this. When using something new we should be extremely careful and we should definitely study it as much as possible. But it is also great to know that the whole world united to fight ozone depletion. Change is possible!

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