At that time, 74,000 square kilometers of eucalyptus forests were destroyed by fire – a larger area than Bavaria. Trees usually extract carbon dioxide from the air and store it in their biomass. But in a fire, the stored carbon is burned and CO2 is released again. In the three months of the Australian Mega-Fires, it could be more than 700 million [*] Tons. And almost twice as much by the annual combustion of fossil fuels on the Fifth Continent.
This is the result of a new analysis by the Netherlands Institute for Space Research. German physicist Jochen Landgraf worked on it: “We are learning how important fire is and we really need to take a more detailed approach to the climate issue – and that fire is relevant in this context.”
(Getty Images / Asiaback / Brett Hemings)Wildfires in Australia –Uncontrolled fires are currently spreading in the states of New South Wales and Queensland off the east coast of Australia. Two experts from Germany report on the possible causes of the fire and the mistakes made by the authorities.
700 million [*] Tons of CO2
The analysis relies on a new instrument in the European Sentinel Series satellite. However, the device does not measure carbon dioxide, but the concentration of carbon monoxide, which is produced in wildfires. In a sense, it is the sister gas of CO2. The two arise in a particular relationship with each other:
“You have to introduce yourself. We’ll take something like a photo of space. In the photo you can see carbon monoxide being distributed in the exhaust bloom. And if there is this exhaust bloom, you can calculate how many emissions are needed to create an exhaust bloom to create it. That’s what we do. That’s the trick.”
Black summer in Australia
So the research team is bringing in a huge amount of more than 700 million [*] Tons of CO2, now called from a fire that broke out in Australia’s black summer. The fire was a disaster for wildlife in southeastern Australia. It is estimated that billions of animals have been killed or driven from the eucalyptus forest.
(Image Alliance / DELWP)Fire ecologist: “We forgot how to deal with fire”
Bush fires like the ones in Australia are the result of long and severe droughts and can no longer be controlled in practice, said Johan Goldmer, a fire ecologist at Dlf. The events of the past decades have shown that reconsideration is essential in dealing with fire.
But the fire had a completely different effect. This is made clear by a second study in the journal Nature. As he says it was a surprise to Nicholas Caesar. The French biochemist is a professor at Duke University in the United States: “The effects of such a catastrophe are far greater than we think. They can affect ecosystems thousands of kilometers away.”
Aerosols fertilized the sea
This is due to the high prevalence of smoke in the wildfire atmosphere. These are called pyrogenic aerosols. These dust particles spread in the air and were blown east to the southern ocean, almost as far as South America, where the flames of the fire sank back to the surface of the ocean. There they acted as compost and led to strong algae blooms. Because, there was a lot of iron in that smoke, it was mostly not in the sea plankton. If there are suddenly a lot of nutrients, the algae will actively multiply:
“Wildfires release large amounts of CO2, but also compost large amounts of aerosols into the sea. When that happens, plankton’s algae absorb CO2, just like terrestrial plants. Of course, they are significant! In Australia.”
Task Force for Future Megaphires
But it is not clear. CO2 is present in the ocean only after the algae has sunk to a depth and is not decomposed on the surface or eaten by marine animals. Then the greenhouse gas ends up in the air again.
Nicholas Cassar is now proposing a task force. In the event of a mega fire in the future, research vessels should go to sea as quickly as possible in order to study the reactions of algae in detail. As wildfires increase as expected, the importance of these processes to climate will grow.
[*] Editor’s note: We have fixed a number at this point.
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