A new study shows the Black Summer bushfires caused extreme changes to the chemistry of the stratosphere. 

Smoke from the Black Summer of bushfires in 2019-2020 produced unexpected and extreme changes to stratospheric gases beyond any seen in the previous 15 years of measurements, according to US and Canadian research. 

The bushfires injected massive amounts of smoke particles high into the atmosphere, producing unexpected and extreme perturbations in stratospheric gases. 

Some of these changes have the potential to destroy ozone – a crucial atmospheric component responsible for protecting Earth’s surface from the Sun’s harmful ultraviolet radiation. 

The findings illustrate the large and long-lasting impact that increasing wildfire activity worldwide can have on Earth’s atmosphere. 

As a result of climate change, extreme wildfires are on the rise worldwide. Such severe wildfires can create pyrocumulonimbus (pyroCb) clouds – enormous heat-induced plumes known to inject massive amounts of smoke and other combustion gases high into the stratosphere, which can affect climate and atmospheric composition in currently ill-defined ways. 

In the recent study, Peter Bernath and colleagues used infrared spectrometer data from the Atmospheric Chemistry Experiment (ACE) satellite to evaluate the impact of smoke particles from the “Black Summer” fires, which raged across Australia in late 2019 and early 2020. 

According to the findings, this influx of smoke resulted in extreme disturbances in stratospheric gas concentrations, including increases in chlorine-bearing compounds, which have the potential to destroy ozone. 

The researchers say that their ACE observations suggest that as severe wildfires become more frequent, their effects will become an increasingly important factor in the global ozone budget of the future.

The latest study is accessible here.

It follows a March 2021 study in Science which found that stratospheric smoke injection from the 2019-2020 Australian wildfires contributed to record-breaking levels of atmospheric aerosols over the Southern Hemisphere, which caused marked cooling over cloud-free ocean regions.