Fires set new emissions record

The Australian bushfires have released enough greenhouse gases to double that country’s annual greenhouse gas emissions from burning fossil fuels, new scientific estimates show.

Guido van der Werf, who helps to maintain the Global Fire Emissions Database, says the fires in New South Wales and Victoria in particular have emitted around 400 million tonnes of carbon dioxide so far, ‘‘pushing country-level estimates for all of 2019 to a new record in the satellite era’’ of about 900 million tonnes of the greenhouse gas.

According to the Global Carbon Project, in 2018 Australia emitted 421 million tonnes of CO2, making it the 16th-largest emitter worldwide, ranking just above the United Kingdom.

Typically, fire-related emissions are not included in annual estimates, since such pollutants tend to be reabsorbed over time. However, this year, vast forest ecosystems that take in carbon and store it in biomass went up in flames. This carbon was released into the atmosphere, and it could take decades for the forests to recover to the point where they are net absorbers of such quantities of CO2 once again.

Full recovery might never happen, particularly if there were more fires in these forests in rapid succession, van der Werf said.

In another indication of the climate change implications of the bushfires, the UK Met office said yesterday that they could account for 1 to 2 per cent of the acceleration in the growth of the global concentration of CO2 in the planet’s atmosphere in 2020.

Last year was the hottest and driest year on record in Australia, and December saw the country shatter its record for the hottest ever day nationally.

With climate extremes becoming more severe and common worldwide as global temperatures increase, real-time wildfire emissions estimates are likely to take on added importance. In 2019, for example, there was a spate of fires throughout the boreal forest in the Arctic, and 2018 was the most damaging and deadly fire year in California’s history.

In Australia, a debate is taking place over whether to thin out forests to make them less fireprone.

Rob Jackson, a professor of Earth system science at Stanford University, said it was possible that by the time the bushfires were finally extinguished, the emissions from this fire season would be close to a billion tonnes of CO2.

It could take decades for the forests to recover to the point where they are net absorbers of CO once again.