The devastating wildfires that occurred during the Australian summer of 2019-2020 released over 700 billion kilograms of CO2 emissions, almost double the emissions from Australia’s annual fossil fuel consumption and comparable to annual emissions from global air travel.

Using satellite data, researchers from VU University Amsterdam and SRON Netherlands Institute for Space Research determined the amount of carbon emissions from the wildfires that raged in Australia’s predominantly eucalyptus forests for a period of three months in 2019-2020. The research was published in Nature.

For more accuracy in estimating CO2 emissions from Australia’s ‘Black Summer’, the researchers decided to use the Dutch space instrument TROPOMI.

"By using satellite data of atmospheric carbon monoxide (CO) concentrations, we can much better estimate the total CO2 emissions,” VU/SRON researcher and first author Ivar van der Velde explained. According to the researchers, TROPOMI measures the impact on the amount of CO in the atmosphere. Using the ratio between CO and CO2 released during fires in eucalyptus forests, the researchers were able to determine the CO2 emissions from the Black Summer fires.

"TROPOMI enables us to monitor wildfires and carbon monoxide emissions much more accurately from space thanks to the high precision of the instrument down to the lowest layers in the atmosphere where the fires occur," Ilse Aben, VU professor and head of the TROPOMI research team at SRON, revealed.

While wildfires are a naturally recurring phenomenon in Australia, particularly in the savanna regions, the Black Summer fires were unique because they were extremely large and raged in eucalyptus forests where such fires are not usually observed, says climate and forest fire expert Guido van der Werf (VU).

Since these large fires are expected to become more frequent in the future, van der Werf believes it will hamper rapid recovery of the affected forests, and part of the emitted CO2 will not be compensated for by CO2 uptake during post-fire regrowth.

“Some of the emitted CO2 will therefore remain longer in the atmosphere and thus contribute to global warming,” he said.