In a strip 20 to 30 kilometers above our heads, in a region of the atmosphere known as the stratosphere , the ozone layer protects the Earth from harmful ultraviolet radiation (UV-B) from the Sun.
And why is this layer so vital? Quite simply, without it, life on Earth would not be possible. Without a protective layer against harmful radiation, life on the surface of our planet would never have prospered, and it would never have left the oceans.
In fact, at the beginning of 2018 a study was published that concluded that the Permian-Triassic mass extinction, the largest in the entire history of the planet, and after which 96% of terrestrial species disappeared, was proven, in part, by a serious decrease in the thickness of the ozone layer.
In the 1970s, scientists first observed that certain chemicals could damage the ozone layer, reducing its thickness and therefore its effectiveness as a protective screen.
And what is more serious, they detected that over Antarctica the thinning of this layer was so intense that, for practical purposes, a kind of “hole” was being formed in the ozone layer that could have catastrophic effects. Subsequent investigations revealed that the main causes of ozone depletion were chlorofluorocarbon compounds (CFCs) , present mainly in sprays, refrigeration systems and air conditioners.
Video: Why it is important to preserve the ozone layer
A little later, political reactions arrived, and dozens of countries have met over the last two decades of the 20th century and the first years of the 21st to adopt global emergency measures, creating various protocols, such as the Montreal one, signed in 1987.
Alarmed by the prediction that in the year 2100 the average temperature of the planet could increase between one and a half and five degrees Celsius if the concentration of carbon dioxide in the atmosphere doubled, 195 countries signed the Paris agreement against change climate, from which the US would later disengage under the Trump administration.
Video: The hole in the ozone layer
A greater deficit of ozone in the atmosphere, although it would not cause an immediate extinction, would cause a significant increase in cases of skin cancer and cataracts . In addition, the increase in ultraviolet radiation on Earth would drastically reduce the levels of phytoplankton , the base of the food pyramid in the oceans, affecting biodiversity.
Damage to the ozone layer would also have negative effects on plant growth , with major repercussions on agriculture.
According to experts, this layer is currently registering “a progressive but slow recovery” , and it will take until 2050 to match the levels prior to the 1980s. The outlook is more pessimistic in the Antarctic area, where it is estimated that the expected levels will not be reached until 2065.
