Smoke injected high into the atmosphere by the 2019-2020 Australian bushfires resulted in a depletion of the ozone layer, new research has found.
Scientists have found that the smoke from the devastating bushfires caused a 1% loss in ozone an amount that typically takes one decade to recover.
The study, published in the Proceedings of the National Academy Of Sciences, suggests rising fire intensity and frequency due to the climate crisis may slow the recovery of the ozone layer.
The ozone layer part of the stratosphere, the second layer of Earths atmosphere absorbs ultraviolet radiation emitted by the sun and consists of a high concentration of ozone molecules.
Researchers have discovered that smoke aerosols reacts with nitrogen in stratosphere, which results in chemical shifts, which causes the depletion.
The study co-author Dr Kane Stone of the Massachusetts Institute of Technology said that the reduction occurred between March 2020 and August 2020.
As the bushfire aerosols leave the stratosphere over time they come back down to the [Earths] surface ozone depletion stops, Stone said. This is a very short-term decrease, but it is significant.
Ozone recovery is currently at a rate of 1% per decade.
Ozone is continually replenished in the atmosphere above tropics. Stone explained that sunlight reacts to oxygen and creates ozone.
Despite the constant production of ozone and its depletion by substances such as chlorofluorocarbons (which were phased out in accordance with the 1987 Montreal protocol), the concentrations have been decreasing.
The globe was blanketed by smoke from the 20192020 Bushfires, which covered the middle latitudes in the southern hemisphere. The pyrocumulonimbus cloud formed during the event three times larger than anything previously recorded ejected smoke particles kilometres upwards into the stratosphere.
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The researchers did not study if the bushfire smoke affected the Antarctic ozone hole, which occurs at more southern latitudes and develops annually during the southern hemisphere spring.
The director of the centre for atmospheric chemistry at the University of Wollongong who was not involved in the research, Prof Clare Murphy, said more intense fires in the future as is predicted by current climate models would slow down the recovery of the ozone layer.
In the stratosphere, the pressure is very low theres not a lot of molecules around, so chemistry typically happens very slowly, Murphy said. You put [smoke] particles up there and suddenly you provide a surface on which the chemistry can happen many orders of magnitude faster.
Murphy stated that coordinated environmental action was a success in addressing the Antarctic ozone hole. There is no reason why humanity shouldn’t work together to solve climate problems.