Has the ozone layer been destroyed before?
Josie Sharp discusses the previous destruction of the ozone layer during the Great Dying.
Almost all living species were victim to the Great Dying. 90% of all marine and 70% of land species all died out during the Permian mass extinction, caused by mass volcanic eruptions on such a cataclysmic scale that it resulted in substantial environmental changes to our earth. For example, the increased volcanic activity released much higher amounts of carbon dioxide, amongst other gases, which caused global warming and ocean acidification.
90% of all marine and 70% of land species all died out during the Permian mass extinction
It is believed that the ozone layer was also damaged in the Great Dying. The eruptions caused a larger number of halocarbons to be released and destroyed the ozone layer, which would have increased the amount of UV light that passed through our atmosphere.
Studies show that pollen grains from this time are more abnormally shaped. One argument to support the ozone layer theory is that these abnormalities are due to the mutation required to withstand the higher concentration of UV rays. Although, with the amount of other toxic substances on the planet at the time, these mutations cannot be theorised as being exclusively caused by higher ultraviolet radiations.
A more recent study used the Fourier transform infrared micro-spectroscopy method to measure the amount of chemicals that absorb UV radiations. This method of detected phenolic compounds showed that high concentrations were produced during the time of the Great Dying. Higher UV radiations would have resulted in a decrease in the growth of plants, creating a domino effect through the whole animal kingdom once the herbivore species began to die of starvation.
Higher UV radiations would have resulted in a decrease in the growth of plants, creating a domino effect through the whole animal kingdom
The destruction of the ozone layer has been prevented again since the signing of the Montreal Protocol in 1987. This protocol included the discontinuation of the use of CFCs. CFCs, also known as chlorofluorocarbons, deplete the ozone layer by releasing chlorine atoms once they rise into the stratosphere as aerosol. The protocol banned the new production and use of CFC’s which have protected the ozone layers condition. In our current climate crisis, treaties like the Montreal Protocol are becoming ever more important in the fight against the use of substances that endanger our planet.
