AUSTRALIA – The bushfire that raged in parts of Australia during 2019-20 released an estimated 715 million tonnes of carbon dioxide into the air. While the fire proved detrimental and fatal for animals and plants in the region, it proved life-sustaining for an ecosystem
thousands of kilometres away in the Pacific Southern Ocean.
The smoke from the deadly bushfire that was rich in nutrients, infused the waters with iron, nourishing phytoplankton microscopic plants which then absorbed carbon dioxide equivalent to as much as 95 per cent of the emissions from the fires.
In a series of research papers, scientists studied the massive amount of carbon dioxide that was released in the air and its impact on the neighbouring environment amid growing threats to the planet from climate change and global warming. The researchers used European satellites to shed light on the complicated ways in which Earth is responding to climate change in an era of worsening wildfires.
BUSHFIRE THAT KILLED A BILLION ANIMALS
Australia is no stranger to wildfires, however, increasing drought conditions due to global warming is leading to more and more bushfires, and the 2019-20 bushfire was one of the worst in its modern history. Local administration estimated the fires burnt 1,86,000 square kilometres of area, destroying over 5,000 buildings and killed over 400 people. More than a billion animals perished from the bushfires, with several endangered species facing the risk of total extinction.
Researchers have now estimated that southeast Australia bushfire released 715 million tonnes of carbon dioxide into the air more than double the emissions provided by fire emission inventory datasets. The bushfire destroyed as much as 74,000 sq km of mostly eucalyptus forest, roughly 2.5 times the area of Belgium. The European Space Agency (ESA) in a statement said that previous estimates from global inventory datasets of wildfire emissions based on satellite fire data and modelled quantities of standing biomass suggested that the fires released on average 275 million tonnes of carbon dioxide between November 2019 and January 2020.
“However, the new analysis indicates that this figure was a gross underestimate,” it added. Researchers used data from the Tropomi instrument onboard the Copernicus Sentinel-5P satellite to obtain a more accurate figure of the destruction caused by the natural calamity. They used the data around carbon monoxide levels in the atmospheric column to calculate a more detailed estimate of the carbon monoxide emissions from the bushfires.
The new estimates surpass Australia’s normal annual bushfire and fossil fuel emissions by 80 per cent.
Researchers found that the aerosols generated by the record Australian bushfire season were “sucked up” by a gigantic phytoplankton bloom in the Pacific Southern Ocean. The plumes, which were rich in nutrients were swept away over the ocean and within days these aerosols had infused the waters with iron, nourishing phytoplankton.
Phytoplanktons are tiny organisms that consume carbon dioxide during photosynthesis. ESA in a statement said that extensive phytoplankton blooms are said to have covered an area approximately the size of the Sahara Desert, more than 9.4 million square kilometres. They observed aerosol plumes using data from the Copernicus Atmosphere Monitoring Service compared the aerosol observations to ocean chlorophyll concentrations recording by ESA’s Ocean Colour Climate Change Initiative project and found peaks in chlorophyll concentrations a few days to weeks later.
Researchers said that the phytoplankton response to the fallout of the Australian wildfires was impressive in terms of both its geographical extent and the magnitude of the anomaly.
It will be interesting to see if ‘megablooms’ such as these become more common, and what the ecological impacts of such blooms could be, as wildfires and other extreme environmental events become more frequent as a result of climate change.