What would happen to the Amazon if the concentration of CO2 reached critical levels? Scientists are anticipating this scenario in a laboratory in the heart of the largest rainforest on the planet.
The top of a metal tower more than 35 meters high overlooks the treetops bushy, 80 km from Manaus, in northern Brazil.
Enclosing the forest all around, sixteen vertical aluminum panels of the same height are erected in a circle to form a “carbon ring” 30 meters in diameter.
These panels will release CO2-enriched air on about fifty trees, transforming this small piece of Amazonia into a sample of an experience that could prefigure the future of the planet.
The AmazonFACE project, co-funded by the governments of Brazil and the United Kingdom, “will make it possible to understand how the jungle will behave in the face of climate change”, explains Carlos Quesada, one of the leaders of the experiment.
< p>“How will it react to rising temperatures and water shortages in a world with more carbon? asks this researcher from the National Institute for Research on the Amazon.
A window to the future
Similar experiments have already been conducted in forests in Australia, the United States or the United Kingdom, but AmazonFACE is the first of its kind in a tropical environment.
By 2024, six rings distributed in the Amazon rainforest will release carbon-enriched air, 40% to 50% more concentrated than the current rate.
Over a period of ten years, researchers will closely examine the impacts on leaves, roots, soils and the water cycle.
The objective: to try to understand “how the Amazon rainforest can help fight climate change by absorbing CO2”, explains David Lapola, a researcher from the University of Campinas, who is coordinating the experiment with Carlos Quesada.
But it is also a question of evaluating “the impact of these changes on the forest”.
The increase in the level of carbon in the atmosphere could cause a “savanization” of the forest. Amazonia, whose vegetation would adapt to higher temperatures and prolonged periods of drought.
But CO2 could also initially make the forest more resistant to climate change, thanks to the increase in biomass.
“It would be a positive impact, at least for a certain period of time, during which it would be very important to put in place drastic emission reduction policies”, considers Carlos Quesada, for whom this experience is a “window on the future”.
“By opening it , we will be able to see what will happen over the next thirty years, and thanks to that, we will save time”, he continues.
The Intergovernmental Panel on Climate Change (IPCC) of the United Nations, warned in a report published in March that global warming will reach 1.5°C compared to the pre-industrial era as early as the years 2030-2035.
A study reference published in 2018 by researchers Thomas E. Lovejoy and Carlos Nobre, estimates that the Amazon will reach its point of no return to turn into savannah if 20 to 25% of its territory is affected by deforestation, compared to around 15% currently.