Since the beginning of August, the Amazon has burned continuously. A disaster that mobilizes the international community, worries about what is often called "green lung" of the planet. The Amazon rainforest, a jewel of diversity, makes it possible to regulate the climate and store CO2. While deforestation has been partly controlled in recent years, the coming to power of far-right President Jair Bolsonaro, a noted anti-ecologist, has wreaked havoc on decades of effort.

What does the Amazon forest represent?

The Amazon basin is home to the largest tropical forest in the world, covering more than five million square kilometers. But about 20% has disappeared in the last 50 years. If 60% of its surface is in Brazil, the Amazon also extends to Bolivia, Colombia, Ecuador, French Guiana, Guyana, Peru, Suriname and Venezuela.

In 2017, of the 160,000 square kilometers of tropical rainforests lost, 35% were in the Amazon and more than a quarter in Brazil.

"The world's rainforests are in a state of emergency," France Seymour, of the World Resources Institute, told AFP recently. "The health of the planet is at stake. With every hectare lost, we are getting closer to the scary scenario of galloping climate change."

The Amazon also has an impressive number of species: 40,000 different plants, 3,000 freshwater fish, nearly 1,300 birds, 370 reptiles.

It is one of the last refuges of the king of the Latin American forests, the jaguar, but also pink dolphins, threatened with extinction. It still has many secrets to deliver since in 20 years, 2,200 new species of plants and vertebrates have been discovered there.

A climatic regulator for the planet

The world's forests - especially those in the tropics - absorb 25 to 30% of the carbon dioxide that mankind releases into the atmosphere (the oceans absorb 20% more.) Without these "CO2 sinks", the temperature on the surface of the Earth would already be much higher and the risk of rapid global warming higher.

In addition, when the forest is burned - usually to produce soy, palm oil, biofuels or cattle - some of the carbon it contains is suddenly released into the atmosphere and accelerates global warming. .

In addition to capturing and storing carbon, forests also affect wind speed, rainfall patterns, and the chemical composition of the atmosphere.

On the other hand, it is incorrect to say that the Amazon is the "lung of the planet", as Emmanuel Macron did in a tweet on Thursday. The French president also wrote that this forest "produces 20% of our oxygen". But according to Jonathan Foley, Executive Director of the Drawdown project, it would be more like "6%, maybe even less".

"There are many reasons to worry about the recent deforestation peaks in the Amazon - carbon, climate, water, biodiversity and people," said Jonathan Foley, executive director of the Drawdown project. "But oxygen, thank God, is not a problem we need to worry about."

Significantly increased fires in recent years

Some 150,000 fires have already ravaged the Brazilian Amazon this year. That's a lot but it's less than in 2016. Between 2002 and 2010, the number of fires in August exceeded five times the 200,000. But the "fire season" usually reaches its peak only in September.

"It seems like a lot of fires in the Amazon are occurring on land that has already been deforested," noted this week's Mikaela Weisse and Sarah Ruiz of Global Forest Watch, based in Washington DC.

In the Amazon, when a forest is cleared, the trunks are washed away but the rest of the vegetation is burned on site during the dry season, which lasts from July to November. For farmland, or grasslands, vegetation and weeds are also piled up, waiting for the dry season. That's what's burning right now, say the experts.

According to data from the National Institute for Space Research (Inpe), a Brazilian organization that observes the evolution of the tropical forest by satellite, from 1988 to 2008, deforestation systematically exceeded 11,000 km² per year, with peaks greater than 20,000 km2 five times: in 1988, 1995, 2002, 2003 and 2004.

From 2005, however, there is a clear reduction in deforested areas and, since 2008, deforestation has never exceeded 10,000 km², with even a historic minimum of 4,600 km² in 2012. A drop especially due to the implementation of proactive public policies.

Paulo Moutinho, of the Institute of Environmental Research of the Amazon (Ipam), cites "the creation of protected areas, campaigns against illegal deforestation, with the detention of those responsible for deforestation, the creation of a blacklist of municipalities with the highest rate of deforestation (...) and the denial of bank loans to those who illegally deforest. "

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He also recalled that during this period, despite the slowdown in deforestation, Brazil has "increased its production of meat and cereals" on land already used by agriculture in the Amazon region.

After a "gradual increase" in deforestation in recent years, the coming to power in January of far-right president Jair Bolsonaro, climate-skeptical, has led to "a change in the government's vision", with "a dismantling public policies to combat deforestation ", the researcher stresses.

With AFP