Brazil will study Amazon reaction to higher CO2 concentration

In the depths of the Amazon, Brazil build a structure that seems out of this world: a complex of towers arranged in six circles that will spray carbon dioxide mist into the rainforest. But the reason is completely earthly: to understand the reaction of the world’s largest rainforest to climate change.

The project, called AmazonFACE, will test the remarkable ability of the forest to absorb carbon dioxide, a crucial component in the climate change puzzle. This will help scientists understand if the region has a critical point that, if reached, could enter a state of irreversible decline. That feared event, also known as the death of the Amazon rainforest, could transform the world’s most biodiverse forest into a more arid, savannah-like landscape.

FACE is the acronym for Free Air CO2 Enrichment. This technology, first developed by the Brookhaven National Laboratory—located near New York City—has the ability to modify the environment around plants in such a way that it replicates future levels of carbon dioxide concentrations in the atmosphere.

“Plants absorb carbon dioxide along with water and light to produce sugars and release oxygen. What happens when that level is increased? We don’t know,” David Lapola, one of the project’s lead scientists, told Associated Press. “We have evidence of similar experiments in temperate forests, but there is no guarantee that the Amazon will react in the same way.”

Lapola, a professor at the State University of Campinas, argues that the critical point in the Amazon rainforest could be more linked to climate change than to the rate of deforestation. Thus, it is crucial to study the consequences of higher concentrations of carbon dioxide in the forest to understand what will happen in the future.

This perspective challenges the much-cited study by Carlos Nobre, an Earth systems scientist. According to Nobre, if deforestation reaches a critical threshold of 20 to 25% in the Amazon, the balance of the region’s rainfall system will be upset, with the subsequent transformation of exuberant tropical forest into savannah.

“Even if we stopped deforestation in the Amazon basin today, the rainforest would still be in danger of experiencing tipping point consequences due to climate change,” Lapola said. “While curbing deforestation remains our main responsibility, combating climate change caused by atmospheric factors is a situation that Brazil and other Amazon countries cannot address alone.”

The construction of the two initial circles is underway and they are expected to come online in early August. Each circle will consist of 16 aluminum towers that will reach the height of a 12-story building. Carbon dioxide will be supplied by three companies to avoid a shortage.

The project, located 70 kilometers (44 miles) north of Manaus, is spearheaded by the National Institute for Amazon Research, a federal institution, with a financial contribution from the British government, which has pledged $9 million. It will be fully operational by mid-2024.

Luciana Gatti, an expert in atmospheric chemistry, praised the initiative and pointed out that it will be very beneficial to replicate the project in all the quadrants of the Amazon, since the carbon absorption capacity varies considerably in the region, which is twice the size of India.

Gatti, who is not directly involved in AmazonFACE, is co-author of an emblematic study published in the journal Nature, which revealed that the eastern Amazon has ceased to function as a carbon sink or absorber for the Earth and has become a carbon source.


The Associated Press receives support for its coverage of climate and environmental issues from various private foundations. The PA is solely responsible for the content.

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