The job of the ozone layer is to filter out medium level ultraviolet light from the sun and, without an ozone layer, the fears were that we would see cases of eye damage and skin cancer rocket. The hole in the ozone layer was the poster child for the climate change cause – a very visible sign of what we were doing to the planet through human activity, and governments around the world started to ban products and raise awareness with the aims of stopping the hole in the ozone layer getting any bigger.
Recent reports however have shown that not only has the hole in the ozone layer stopped growing, it appears to be healing itself.
The size of the hole in September 2015 was 4 million square kilometres smaller than it was back in 2000, an area equivalent to half of the size of the USA.
So what's going on and are there any secrets which can be shared for the resolution of other environmental concerns?
The hole in the ozone layer is not static and measuring can be difficult. The hole in the ozone layer over Antarctica is at its peak in October, when the days are longest in the Southern Hemisphere and the ozone depletion is at its greatest rate. Scientists have decided the optimum time to measure the size of the hole in the ozone layer in is September, so figures are only produced yearly. The scientific team in charge of the measuring use a combination of weather balloons, satellites and a range of other measurements to arrive at the agreed size of the hole. The hole in the ozone layer only forms over Antarctica due to the extremely low temperatures, which are not experienced anywhere else on the planet, and which cause chlorine to react on the surfaces of the wispy clouds which form high up in the stratosphere.
In the late 1980s, scientists were quick to establish that man-made chemicals released into the atmosphere were damaging the ozone layer. The main culprits were the chlorofluorocarbons, or CFCs.
CFCs are compounds of carbon, chlorine and fluorine and were often used to make propellant gases for aerosols, foam and other packing materials, refrigerators and air conditioning units. As far back as 1974, scientists had shown that CFCs could potentially be environmentally damaging. A great deal of effort was put into negotiating a gradual phasing out of CFCs across the world, and into the development of alternatives which were equally effective but far less environmentally damaging. In developed nations, the use of CFCs was banned completely by 1995, with only a very small number of exceptions made for essential laboratory use. This effort to ban CFCs internationally is unprecedented and UN Secretary General, Kofi Annan, described it as “the single most successful international agreement to date”.
CFCs take decades to be removed from the atmosphere and scientists predict that, based on current rates of ozone hole shrinkage, the damage could be completely reversed by the 2050s.
Close monitoring of the atmosphere over Antarctica is essential, especially as from time to time anomalies in the progress of healing the hole appear. In 2014, the eruption of the Calbuco volcano in Chile caused the formation of many more of the tiny particles which cause ozone loss, giving the impression that the hole in the ozone layer was bigger than ever.
The other issue to consider is the effect on the environment of the chemicals which were designed to replace the CFCs.
New chemicals, called hydrofluorocarbons (HFCs) certainly don’t have the damaging effect on the ozone layer as the CFCs but have instead been linked to greenhouse gases which are linked to global warming and changing weather patterns across the globe.
Global warming has the potential to be every bit as damaging to the environment as CFCs were back in the 1980s and the solution is far less simple.
Developed countries have made great strides in reducing their carbon footprint and the amount of carbon dioxide produced by their homes, cars and factories but the same cannot be said for developing nations and large nations, such as China and India. It remains to be seen whether the international community can achieve the same success in reducing greenhouse gases and global warming as they enjoyed with CFCs and the chances are that we will have to wait several decades to see whether or not our actions are having an effect on the planet.