The Amazon absorbs more CO2 than it rejects and stores 90 to 140 billion metric tonnes of CO2, according to the WWF, which warned that "the release of even a portion of which would accelerate global warming significantly."
With an area of 5.5 million km², the Amazon is the largest tropical forest on the planet. A treasure trove of biodiversity, it is threatened by deforestation mainly due to agriculture, livestock and mining activities and is currently in the grip of intense wildfires.
Sanctuary of biodiversity
The Amazon basin (7.4 million km²) occupies nearly 40% of South America's landmass and is spread over nine countries: Brazil, Bolivia, Peru, Ecuador, Colombia, Venezuela, Guyana, Suriname and Guyana (France).
About 60% of its surface is in Brazil.
The forest, of which 2.1 million km² are protected areas, is home to an unparalleled biodiversity: a quarter of the world's species are present there including some 30,000 species of plants, 2,500 of fish, 1,500 of birds, 500 of mammals, 550 of reptiles and 2.5 million insects, according to the Amazon Cooperation Treaty Organization (ACTO).
Since 1999, more than 2,200 species of plants or animals have been discovered there.
'Lung of the planet'
The Amazon contains one-third of the world's primary forests and, thanks to the eponymous river and its tributaries, 20% of the unfrozen freshwater.
It is the world's most important river in terms of output. It is also the longest, measuring 6900 km.
Furthermore, it absorbs more CO2 than it rejects and stores 90 to 140 billion metric tonnes of CO2, according to the World Wide Fund for Nature (WWF), which warned that "the release of even a portion of which would accelerate global warming significantly".
Deforestation and fires decrease the forest's capacity to absorb CO2.
The region has been inhabited for at least 11,000 years, and now counts 34 million people — two-thirds of whom are city dwellers.
But nearly three million Indians from 420 tribes also live there according to ACTO. About sixty of these tribes — who speak 86 languages and 650 dialects — live in total isolation.
The largest is the 40,000-member Tikuna tribe which resides across Brazil, Peru and Colombia, according to the NGO Survival International.
The Brazilian Indian chief of the Kayapo tribe, Raoni Metuktire, is one of the most prominent figureheads in the fight against deforestation in the rainforest. He has been roaming the world since 1989 to draw attention to the deforestation and the plight of the Amazon's indigenous peoples.
Manaus: 'Capital of the Amazon'
The region is also home to the country's third-biggest industrial hub, Manaus, which has a population of 1.8 million.
Founded by the Portuguese in 1669 on the banks of the Rio Negro, near its confluence with the Amazon, it grew rapidly towards the end of the 19th century thanks to the rubber trade before declining significantly.
Since the creation of a free economic zone in 1967, the city primarily relies on its industrial sector which imports spare parts and exports finished products, particularly electronic equipment.
Nearly 20% of the Amazon rainforest has disappeared in 50 years, according to WWF. And the phenomenon is accelerating.
In Brazil — led since January by climate-denier Jair Bolsonaro — deforestation in July was almost four times higher than during the same month last year, according to the DETER real-time detection of deforestation system used by the National Institute for Space Research.
This public body charged with measuring deforestation in the Amazon reported that 2,254 km² of forests were destroyed in Brazil last month, compared to 596.6 km² in July 2018 — an increase of 278%.
The main causes of deforestation are agriculture (soybean), livestock farming, the construction of hydroelectric dams and road infrastructures, the mining industry — the region is rich in gold, copper, tantalum, iron ore, nickel and manganese —, forest fires and timber trafficking.
Fire is also one of the main tools used for deforestation and clearing — by which vegetation, together with their roots, are permanently removed — including by farmers.
In turn, deforestation "contributes directly to a change in rainfall patterns in the affected region, extending the length of the dry season", according to Greenpeace. This makes wildfires potentially even more dangerous.