Australia’s bushfires have so far burnt about 12 million hectares, including more than 5.2 million hectares in NSW, 2.5 million in Queensland, 2.2 million in Western Australia, 1. 4 million in Victoria and about half a million in South Australia.
“While human-caused emissions cause the CO₂ rise in concentration, impacts of weather patterns on global ecosystems are predicted to increase the rise by 10 per cent this year,” the Met Office statement said.
“Emissions from the recent Australian bushfires contribute up to one-fifth of this increase,” it added.
Estimates this year indicated the fires had resulted in at least 350 million tonnes of CO₂ – or about two-thirds of Australia’s annual emissions – based on burning of 5 million hectares. Global treaties typically do not count such emissions to a national account since the incinerated vegetation is assumed to grow back eventually.
“Although the series of annual levels of CO₂ have always seen a year-on-year increase since 1958, driven by fossil fuel burning and deforestation, the rate of rise isn’t perfectly even because there are fluctuations in the response of ecosystem carbon sinks, especially tropical forests,” Professor Richard Betts, of the Met Office Hadley Centre for Climate Science and Services and the University of Exeter, said.
“Overall these are expected to be weaker than normal for a second year running,” he said.
Australia posted its hottest and driest year on record in 2019, factors that contributed to the readiness of forests to burn, climate scientists have said.
This year, atmospheric concentration of CO₂ are expected to peak above 417 parts per million in May, while the average for the year is forecast to be 414.2 ppm, with a range of plus or minus 0.6 ppm, the Met Office said.
This annual average represents an increase of 2.74 ppm, with a range of plus or minus 0.57 ppm rise, on the average for 2019, it said.