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Forests on earth are burning to an unprecedented extent.

"The 2019/2020 fires in Australia had never before been seen on this scale," says fire ecologist Johann Georg Goldammer.

If an industrial state like the USA cannot extinguish the fires in California in 2020 for months, that also shows that “they are different than before”.

The fires in northern Eurasia and on Greenland in recent years have not yet been registered in this way.

“Climate change is leading us into a completely new situation,” says Goldammer, Director of the Global Fire Monitoring Center (GFMC), which is located at the Max Planck Institute for Chemistry and the University of Freiburg.

Fires drive tens of thousands of people from their homes

The forest and bush fires on the US west coast in California have meanwhile also wreaked havoc on the world-famous wine-growing regions of Napa and Sonoma Valley.

Tens of thousands of people are on the run.

Source: WORLD / Raphael Knop

"Fires are a natural phenomenon," says geoecologist Kirsten Thonicke from the Potsdam Institute for Climate Impact Research (PIK).

In 2020, however, they would have been unusually large, in some regions for the repeated time, she says.

According to Thonicke, around 800,000 hectares of land were already burning in California in 2018 and an estimated twice that area in 2020.

The five-year average for 2014 to 2018 is 416,000 hectares of land.

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In 2020 some mega-fires burned into November.

“This is a new level of quality,” says Thonicke.

Then in December there were new fires.

For comparison: Germany, which is only slightly smaller than California, also experienced extreme forest fires in the heat of 2019, albeit with a much smaller total area of ​​2,711 hectares - nevertheless, according to the Federal Environment Agency, it was the second largest expansion since statistics began in 1977.

"The long drought of the summer months and negligence are the main reasons for the extraordinary forest fire year," writes the office.

In 2019, the largest fire area was in Brandenburg.

However, according to Thonicke, the contribution of climate change cannot be clearly demonstrated there.

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According to Thonicke, there was an unusually large number of fires in Siberia as early as 2019 during the heat and drought.

In 2020, the heat wave in June was much stronger.

"Otherwise there would have been such big fires there about every 20 years and now for two years in a row," says Thonicke.

Forests in Russia have been on fire for weeks

In June alone, 59 megatons of carbon dioxide went into the air.

The forests in Russia have been burning for weeks.

This is due to the great heat in the taiga, but arsonists are also on the way.

Source: WELT / Christoph Wanner

"In Siberia we have long observed that the combination of large-scale clearcuts and fire leads to the formation of“ green deserts ”, that is, the formation of grass steppes," says Goldammer.

The development is now being promoted by climate change.

"Wrong forestry, fire and climate change are mutually reinforcing."

In Australia, almost 20 percent of the country's eucalyptus forests burned in the summer of 2019/2020, Thonicke says.

In the previous two decades it was only two percent on average.

The extreme fires in South Australia would have caused many storm clouds.

“These pyro clouds even generated their own weather, triggering 17 additional thunderstorms that sparked new fires,” says Thonicke.

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According to estimates by the environmental foundation WWF, almost three billion mammals, reptiles and other vertebrates lived on the 19 million hectares of burned forest and bushland of Australia.

Many were burned, others were exposed to smoke inhalation, heat stress and dehydration.

“It has been statistically proven that climate change has made a decisive contribution,” says Thonicke, referring to fires in Siberia, the Arctic, Australia and California.

The big fires often followed a long drought or severe heat wave.

In the northern hemisphere, the extraordinary droughts are related to the jet stream, explains the researcher.

This is the high current of air that meanders around the northern hemisphere.

Since the polar regions warm more than mid-latitudes, the temperature difference between them becomes smaller.

Therefore, according to statements by climate researchers, the meanders more often stay in one place, so that even low and high pressure areas can remain standing for weeks.

According to Thonicke, there was a similar blockade situation in Australia.

According to Goldammer, the droughts associated with climate change have two decisive effects on fires worldwide.

"On the one hand, they put ecosystems that have not been affected by fire, such as rainforests or tundra, into readiness to burn," says the fire ecologist.

"On the other hand, in extreme drought, already degraded ecosystems and open landscapes such as savannahs are less flammable because little or no vegetation grows back."

In the Amazon region of Brazil there were even more fires in 2020 than in 2019, says Thonicke.

There is also a special case here, as the government encourages farmers to make the forest usable for agriculture, while at the same time environmental authorities and the fire brigade have to accept financial cuts.

“These are not forest fires, this is forest burning,” emphasizes GFMC Director Goldammer.

With this active conversion of the forests into plantations or pastures, not only is biodiversity lost, but a lot of carbon dioxide is also produced.

According to Goldammer, willows store around 6 to 12 tons of carbon per hectare, and rainforest 300 to 600 tons.

Highest number of forest fires since 2013 in Brazil

In Brazil, the number of forest fires increased dramatically.

72,843 fires were counted between January and August.

Source: Reuters

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According to Goldammer, however, humans also help reduce fires.

The reason is simple: In many regions of the world, nature is increasingly used.

The associated fragmentation of natural and cultural landscapes leads to a reduction in the spread of fires over a large area.

According to Goldammer, natural - sustainable - forest fires remove carbon dioxide in the long term from the atmosphere: When a forest grows again, it absorbs the CO2 that was created during the fire.

In many forests, such as in Siberia, fire is even necessary to clear and rejuvenate them.

"The remaining trees then become more vital."

The fires also produce charcoal, which gets into the ground or into the sea via rivers and is deposited.

For a long time, forest fires even removed CO2 from the atmosphere, explains Goldammer.

According to calculations by British researchers

Between 1997 and 2016, around twelve percent of the carbon released by the global fires remained bound in charcoal.

If there is no longer the time between fires for forest growth, however, overall, carbon dioxide will be released into the atmosphere through the fires, says Goldammer.

Grasslands, for example, took less than a year to restore themselves, while some forests took decades.

In extreme cases, such as in tropical moorlands or in the Arctic, full recovery can sometimes only be expected after centuries.

The intensity of the fire is also crucial.

"In Australia the eucalyptus trees do not sprout to the extent that would be expected after an ordinary fire," says Goldammer.

The violence of the fire also damaged the organic matter in the soil.

Due to the strength of the fire and the repetition in a short time, it is currently unclear how much CO2 the growing forest can absorb from the atmosphere.

"This fire regime that is now developing is releasing CO2," says Goldammer.

How much exactly on the individual continents can only be determined through lengthy observation.

"The landscape fires have a completely different dimension today than they did five years ago."

Climate protection is important in order to slow down the effect of global warming on fires, says Goldammer.

But that can't help immediately.

The active destruction of ecosystems, on the other hand, could be solved most easily - purely through politics.

So Indonesia is rebuilding its moors on a large scale.

Some politicians and environmentalists in Germany and the EU rely on a supply chain law that should take into account not only human rights but also the environment.

It could ban the sale of beef and other goods that were destroyed in rainforest for production.