Australia’s ‘Black Summer’ fires affected ozone layer: Study

SYDNEY: Australia’s catastrophic “Black Summer” bushfires significantly affected the hole in the Earth’s ozone layer, according to a new report published Friday (Aug 25).

The report, which appeared in the Nature journal “Scientific Reports”, traced a link from the unprecedented smoke released by the fires to the ozone hole above Antarctica.

The fires, which burned through 5.8 million hectares of Australia’s east in late 2019 and early 2020, were so intense they caused dozens of smoke-infused pyrocumulonimbus clouds to form.

Pyrocumulonimbus clouds, referred to as the “fire-breathing dragon of clouds” by NASA, are so powerful they can affect the local weather, causing fire tornadoes and lightning storms.

During the “Black Summer”, these clouds shot more smoke high into the atmosphere than the previous record, set by the 2017 North American wildfires.

Around New Year 2019, uncontrolled fires along Australia’s east coast caused a pyrocumulonimbus event that stretched on for days.

The result was “millions of tonnes of smoke and associated gases being injected into the upper troposphere and lower stratosphere”, according to researchers from the University of Exeter and the University of Manchester.

A build-up of smoke particles, in turn, caused the lower stratosphere to warm to levels not seen since the eruption of Mount Pinatubo in 1991, they found.

Because of this stratospheric warming, the fires also prolonged the Antarctic ozone hole, which appears above Antarctica each spring and “reached record levels in observations in 2020”.