‘Incredibly important advance’ reveals how wildfires could slow ozone layer recovery
Chlorine chemistry discovery shows how wildfire aerosols can reduce ozone in southern hemisphere by up to 5%
The mystery of how wildfire smoke alters the chemistry of the stratosphere to cause ozone depletion has been solved. The findings suggest that more frequent and intense wildfires in a warming climate could potentially delay the recovery of the ozone layer, which protects us from harmful UV radiation.
It was previously known that aerosols from wildfire smoke can reach the stratosphere and it was assumed they acted like volcanic ash by increasing the surface area for reactions that can convert chlorine containing molecules, largely derived from CFC emissions, into more reactive forms of chlorine, which in turn destroy ozone.
However, after the late 2019, early 2020 Australian bushfires, satellite measurements of stratospheric chemistry threw up data that could not be explained by this assumption. It revealed a record low of hydrogen chloride, a record high of chlorine nitrate, combined with low ozone in the mid-latitudes.