A study published October 21, 2026, found that Amazonia’s average total carbon flux was positive from 2010 to 2024, meaning the region released more carbon than it absorbed by that measure. But the study’s net biome exchange, which subtracts estimated fire emissions, was close to neutral. The researchers identified direct human disturbance as the main driver of differences between years, with drought and heat intensifying fire emissions.
What the 2010–2024 measurements mean
The study’s annual averages were 0.32 ± 0.08 petagrams of carbon per year for total carbon flux (TCF), 0.40 ± 0.07 for fire carbon flux (FCF), and −0.08 ± 0.12 for net biome exchange (NBE). TCF is the overall carbon flux; FCF is the portion attributed to fires. NBE is calculated as TCF minus FCF and includes natural sources and sinks as well as human-caused emissions other than fires.
A carbon sink absorbs more carbon than it releases over a given period; a carbon source releases more than it absorbs. In this study, TCF points to a net source across the full budget, while NBE was near neutral after fire emissions were subtracted. Neither average means that every place in the study area behaved the same way each year.
How researchers measured Amazonia’s carbon flux
The team analyzed 1,017 aircraft vertical profiles collected at four sites between 2010 and 2024. Each profile sampled carbon dioxide and carbon monoxide at 12 heights, from about 300 meters to 4.4 kilometers above sea level. The sites’ regions of influence represented about 95% of the study’s defined Amazonia area, which includes Amazonia proper, the Guianas and Gurupi forest ecosystems.
The researchers compared those measurements with land-use and climate data, then grouped the 15 years by their shared conditions. They reported a longer-term change too: comparing 1979–2018 with 1979–2024, annual precipitation fell by 174 ± 69 millimeters, or 8%, while mean annual temperature rose by 1.13 ± 0.13°C.
Three groups of years, three different average fluxes
The study’s year groups show how the reported mean TCF varied with disturbance and climate conditions. The authors’ main results give the following averages:
| Study group and years | Conditions described in the study | Mean TCF (Pg C yr−1) |
| 2011–2014, 2017–2018 | Wetter years with low human disturbance | 0.11 ± 0.08 |
| 2019–2022 | High human disturbance and comparatively low climate stress | 0.43 ± 0.09 |
| 2010, 2015–2016, 2023–2024 | Warm, dry years with climate extremes and increased burning | 0.49 ± 0.07 |
The differences support the study’s conclusion that direct disturbance, including deforestation, forest degradation and burning, dominated variation in carbon flux. Climate stress amplified fire emissions; the two pressures were not treated as interchangeable explanations.
Why 2023 and 2024 stand out
The 2023 wet season had the strongest seasonal carbon sink in the study’s 15-year record. The researchers reported 2024 as the series’ highest annual TCF, at 0.81 ± 0.09 Pg C per year, in hot, dry conditions with intense fire emissions.
For 2023 and 2024, the researchers matched active-fire detections with cloud-to-ground lightning strikes recorded within 72 hours and a one-kilometer buffer. Lightning-associated ignition accounted for 1.6% of the matched result in 2023 and 1.0% in 2024. The study’s broader conclusion was that fires in the warm, dry years were primarily human-induced and amplified by drought.
The authors noted that aircraft profiles ended at 4.4 kilometers, monthly gaps in some flux data were filled statistically, and use of a single average carbon monoxide-to-carbon dioxide ratio may have underestimated fire emissions in the drought years 2023 and 2024.
How the Amazonia result fits global forest estimates
A global forest synthesis estimated an average gross forest carbon sink of 3.56 ± 0.37 Pg C per year and a global net forest sink of 1.33 ± 0.63 Pg C per year over 1990–2019, after accounting for tropical deforestation emissions. It found tropical forest lands fluctuated between a small net source and sink, from −0.1 to 0.6 Pg C per year across decades.
Those global estimates use different geographic boundaries and accounting measures from the Amazonia study’s fire-inclusive TCF and its NBE for 2010–2024. Gross uptake, net forest flux and a regional budget that includes fire emissions describe different parts of the carbon balance.
