The Australia bush fires, which are still burning and killed three more people this week, have released enough greenhouse gases to double the country's annual greenhouse gas emissions from burning fossil fuels, new scientific estimates show.
Guido van der Werf, who helps maintain the Global Fire Emissions Database, says the fires in New South Wales and Victoria in particular have emitted around 400 million tons 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 tons of carbon dioxide.
The smoke plumes from the fires have circled the globe and have turned glaciers brown in New Zealand, led to reddish sunsets in South America and may have reached Antarctica.
According to the Global Carbon Project, in 2018 Australia emitted 421 million tons of carbon dioxide, making it the 16th-largest emitter worldwide, ranking just above the U.K. Typically, fire-related emissions are not included in annual estimates of a country's emissions, since such pollutants tend to be reabsorbed over time.
In a typical fire year in Australia, large amounts of grasslands burn in sparsely populated areas. The carbon emitted by these fires tends to be reabsorbed during the following wet season.
However, this year, vast forest ecosystems that serve as long-term carbon savings accounts, having taken in carbon and stored it in biomass, went up in flames, such as in the Blue Mountains of New South Wales. This carbon was released into the atmosphere during the fires, and it could take decades for the forests to recover to the point where they are net absorbers of such quantities of carbon dioxide once again.
In fact, full recovery may never happen, particularly if more fires burn in these forests in rapid succession, van der Werf noted.
In another indication of the climate change implications of the bush fires, the U.K. Met office said Friday that the Australian fires could account for 1 to 2% of the acceleration in the growth of the global concentration of carbon dioxide in the planet's atmosphere in 2020.
Van der Werf cautioned that the Australia fire emissions estimate comes with "substantial" uncertainties traced mainly to the unprecedented nature of these fires.
Niels Andela, a research scientist at NASA who also works on the fire emissions database, says two independent examinations of greenhouse gas emissions from the 2019-2020 bush fires both reached similar conclusions, bolstering his confidence in the numbers.
More accurate measurements will require information about the ecosystems burned as well as the precise burned area, which takes time to generate.