The Brazilian Amazon has been a net carbon emitter since 2016

Rapid deforestation outweighs carbon capture by remaining trees

If rainforests were Earth’s respiratory system, the Amazon would be a full lung. The region holds half of the tropics’ undisturbed forests. Its flora absorb 1.5bn tonnes of carbon dioxide (CO2) a year, equivalent to 4% of emissions from fossil fuels.

This lung is being deforested at cancerous rates. A chunk nearly the size of Kuwait is felled or burned every year. This both eliminates CO2-absorbing trees and releases their stored carbon back into the air.



−1,000

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1,500

2005

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15

20

21 emissionsremovals

BRAZILPERUCOLOMBIAVENEZUELAGUYANASURINAMEBOLIVIA Amazon River Manaus Porto Velho Belem cuba


The Brazilian Amazon is fixed—5.37m square kilometers in 2005. Here you can see a five-year trailing average of the forest’s carbon flux. Most of its area (in green) absorbed CO2 and stored it away.

During the early 2000s soya farmers and cattle ranchers hungry for land cleared 20,500 square km a year. Where deforesting occurred, the Amazon’s stored carbon was emitted (areas in purple

Late in the decade, CO2 output fell as the central bank cut off credit to firms facing fines for deforestation, and more forest areas gained legal protection. The Brazilian Amazon returned to being a net carbon sink.

But in 2012 the government granted an amnesty for past deforestation, and in 2014 a recession began, which may have pushed farmers to seek new land.

In 2016, emissions surged: 32,600 square km were felled in that year alone, and the destruction has continued at pace ever since.

Over the past 20 years, the Brazilian Amazon has lost 350,000 square km and emitted 13% more CO2 than it absorbed. The trend shows little sign of reversing soon.


The worst scenarios involve a tipping point of tree loss, beyond which the forest could no longer produce enough moisture to sustain its ecosystem. But even if this disaster can be averted, grave harm has already been done. Every year of continued logging reduces the forest’s ability to retain carbon: since 2001 the Brazilian Amazon’s absorption rate has fallen by 1.2% a year.

Two analyzes from 2021 identified chunks of the Amazon as net emitters. one, in Nature, found this pattern in atmospheric samples from south-eastern Amazonia. The other built on a paper in Nature Climate Change, which combined satellite images of tree losses with data on soil types; tree densities and ages; and the emissions impact of land-use changes. Based on the resulting estimates of CO2 flows, authors at MAAPa conservation group, calculated that in 2001-20 net emissions from the Brazilian Amazon exceeded those of Argentina or Pakistan—although the full Amazon, including parts of the forest in neighboring countries, remained a net carbon sink.

Both of these studies measured emissions over long time periods. Neither reported whether recent region-wide trends were positive or negative. To find out, we matched up the latest data on CO2 flows with yearly maps of tree cover to generate the maps above.

Greenhouse gas flows, average for 2001-21

Tonnes of CO₂ equivalent per square km

A few regions with sky-high

emissions outweigh a larger

area with modest absorption

Brazil has pledged to end illegal deforestation by 2028. However, Jair Bolsonaro, the president, has relaxed enforcement of environmental safeguards. Satellite images suggest that twice as much forest has been lost in 2022 as the average for January to April in 2010-21. The future path of global warming depends in part on whether Mr Bolsonaro is re-elected this year.

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