The ozone layer is a layer of gases, containing a significant amount of ozone (O3), that is located 30-50 km above our earth’s surface. The ozone layer is in the part of the atmosphere called the stratosphere, and it is about 20 km thick. The ozone layer protects the planet, and the organisms that live on it, from the harmful UV rays emitted by the sun – it absorbs these rays.
However, because of human use of CFCs (which contain chlorine that destroys O3) a hole in the ozone layer developed in the twentieth century and was discovered in the mid 1980s. CFCs are also sometimes referred to as ODS, which stands for ozone depleting substances.
This hole in the ozone layer was located above Antarctica. It shrunk and expanded depending on the season, and nowadays is present only in the spring time. It has had devastating effects already because it allowed more UV rays to hit the earth, putting human inhabitants at increased risk from sunburn, eye cataracts, and skin cancer, causing temperatures on earth to rise and accelerating the rate at which the ice caps are melting due to climate change. Once CFCs were banned under the 1987 Montreal protocol agreement, the ozone layer’s hole began to shrink significantly – a positive development that shows that humans can turn around the damage that we have done to our planet. However, the hole in the ozone layer is still present and so we need to make sure that it carries on shrinking. Scientists have calculated that by 2065, it should have healed back to the levels that it was at prior to the 1980s.
This hole in the ozone layer is not the full story when it comes to problems with the ozone layer, though. Throughout the stratosphere, human use of CFCs and similar substances led to the thinning of the ozone layer in various points. If this thinning was allowed to carry on, it would have resulted in further holes developing. The most significant patch of thinning ozone was over Australia, and a thinner ozone layer meant that the ozone layer was less able to absorb UV rays and filter them out of our atmosphere. Throughout the 1960s alone, the ozone layer over Australia depleted by as much as 9% – this means that around 2 km of ozone was lost in just a decade. Australians are already at greater risk from the sun’s rays due to their year round sunny climate, and so this thinning of the ozone layer has been very bad news. Luckily, as humans continue to prohibit all non essential use of CFCs, the thinned areas of the ozone layer have begun to slowly build up again.
Our ozone layer: a precious resource.
The ozone layer has been protecting our planet for billions of years, and it is essential for creating a climate that is suitable for humans to live in. And yet it is so fragile: just a few decades of human activity caused several kilometres wide holes to appear in it above sensitive polar regions.