Climate change is not the only planetary-scale environmental challenge that humanity has had to face in recent decades. The last decades of the 20th century had a very different protagonist: the hole in the ozone layer.
Latest report. The United Nations Environment Program (UNEP) and the World Meteorological Organization (WMO) have confirmed that the restoration of the ozone layer is on a favorable path and have set a date for its recovery in different areas of the world: it will be, If everything goes as it is now, between 2040 and 2066.
The “last stronghold” of this stubborn hole would be Antarctica. According to the latest quadrennial assessment report from the Montreal Protocol Scientific Assessment Group, the ozone layer will reach 1980 levels by the year 2066. This would put us somewhat halfway in this restoration process.
However, the layer will heal in other latitudes much sooner. According to the report, by 2045 the hole in the Arctic could close. This hole is smaller and was detected more recently than the Antarctic hole. Outside the two polar regions, the healing of this atmospheric layer could occur in less than two decades, around the year 2040.
History of a planetary hole. The hole in the ozone layer is an almost forgotten environmental problem, although it often revives when it comes to discussing climate change. The problem with the ozone layer was identified in the mid-1980s.
Scientific studies then confirmed that the use of a series of chemical compounds, chlorofluorocarbons (CFCs), gases that were frequently included in aerosols of different types, from those used in cosmetics to insecticides. These gases reached the atmosphere where the chlorine of these compounds interacted with ozone (O3), decomposing this molecule.
This soon became a problem, since ozone is important for life on our planet as it is responsible for absorbing a good part of the ultraviolet (UV) rays that reach Earth from the sun. The loss of this layer of sun protection would imply, among other things, a greater probability of suffering from skin cancer.
Global action. The reaction of the international community to this problem can be considered an example of success in its field. In 1987 the Montreal Protocol was signed, which came into force two years later. The treaty put an end to the emission of CFCs.
The effects of the ban were not immediate, but the situation of the hole was alleviated, first as its expansion stopped and later as its recovery began. According to the latest report, if current policies can be maintained, by mid-century the problem will continue to move towards resolution.
And climate change? The relationship between the problem with the ozone layer and climate change is complex. Although the state of the ozone layer is not closely linked to global warming and its effects on the climate, some of the actions developed within the framework of the Montreal Protocol could have had some effect on the climate. Luckily, once again the parties involved took action on the matter.
The reason is that both hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs), two groups of chemical compounds used during the first years of the CFC phase-out, turned out to be greenhouse gases, so their use has been limited, for example by the Kigali Amendment to the Montreal Protocol.
The international action carried out in defense of the ozone layer, with its parallels and important differences, can serve as an example of the capacity of the international community to solve common problems. Something that, for now, does not seem like it will soon be extrapolated to the problem of climate change.