The massive bushfires in Australia from late 2019 to early 2020 produced so many smoke particles that they raised the region’s stratospheric temperature by about six months.
Wildfires in Australia from December 2019 to January 2020 destroyed trees, bushes, and houses on an area of about 5.6 million hectares. The fires were so large that astronauts aboard the International Space Station saw the smoke. The Australian government estimated that the cost of responding to the fires was approximately $103 billion. Researchers found that black particulate smoke entered the stratosphere in a new study, causing temperatures to rise.
The stratosphere is located about 10 to 50 km from the Earth’s surface – notably, it is also the part of the atmosphere that holds the ozone layer. Previous research has shown that, in some cases, smoke can cool the atmosphere by blocking heat from the Sun. But in some cases, the opposite may happen. If the smoke contains a large number of solid particles and they are black, it can absorb heat from sunlight and transfer it to the surrounding air.
To calculate how much heat was absorbed by the stratosphere, the researchers entered fire data into the Aerosol and Radiation Model for the Atmosphere (CARMA) and the Earth Systems Model (CESM). Both were developed at the University of Colorado and allowed scientists to make predictions about how much heat was captured by particulate matter and its effect on stratospheric temperature. They found that the region’s temperature had risen from 1 to 2 degrees Celsius and remained that way for about six months. The scientists also noted that the smoke particles temporarily increased the size of the ozone hole.
A team of scientists from the University of Jinan, the University of Colorado at Boulder, the National Oceanic and Atmospheric Administration, and the US National Center for Atmospheric Research published the study results in Geophysical Research Letters.