Research led by USP scientists quantifies, for the first time, impacts of forest loss and global climate change in the biome
The deforestation of the Brazilian Amazon is responsible for about 74.5% of the reduction of rainfall and 16.5% of the increase in biome temperature in the drought months. For the first time, researchers were able to quantify the impacts of vegetation loss and global climate change on the forest.
Led by scientists from USP (University of São Paulo), the study brings fundamental results to guide effective mitigation and adaptation strategies, target themes of the United Nations Climate Conference, COP30, scheduled for November in Belém (PA). The results of the work are in the last edition of Nature Communications And they are highlight of the cover of the magazine.
Scientists analyzed environmental data, atmospheric changes and land coverage of approximately 2.6 million km2 –29 blocks with an area of about 300 km by 300 km each – in the Brazilian Legal Amazon over a period of 35 years (1985 to 2020). Using parametric statistical models, they unraveling the effects of forest loss and changes in temperature, precipitation and greenhouse gas mixture rates.
The rains showed a reduction of about 21 mm in the dry season per year, with deforestation contributing to a decrease of 15.8 mm. The maximum temperature increased by about 2 ° C, 16.5% attributed to the effect of forest loss and the remainder to global climate change.
“Several scientific articles about the Amazon have already been showing that the temperature is higher, that rain has decreased and the dry season has increased, but there was no separation of the effect of climate change, caused mainly by pollution from northern hemisphere countries, and deforestation caused by Brazil itself. Through this study, we managed to separate and give weight to each of these components, practically showing a kind of ‘account to pay'” “says the teacher.
Researcher at IF-USP (Institute of Physics of the University of São Paulo) and collaborator of the Department of Chemistry of the Max Planck Institute in Germany, Machado tells the Agency FAPESP that the results reinforce the importance of forest conservation standing to maintain climate resilience.
This is because research has shown that the impact of deforestation is more intense on the early stages. The biggest changes in the local climate are already in the first 10% to 40% of loss of forest cover.
“The effects of transformations, especially in temperature and precipitation, are much more important in the first percentages of deforestation. That is, we have to preserve the forest, this is very clear. We cannot turn it into something else, such as pasture areas. If there is any kind of exploration, it needs to be sustainable.”says the professor, from the IAG (Institute of Astronomy, Geophysics and Atmospheric Sciences) of USP.
Franco is the 1st author of the article and received postdoctoral scholarship from FAPESP (São Paulo State Research Support Foundation), which also supported work through another scholarship, (Greenhouse Gas Research and Innovation Center) and a project linked to the global climate change research program.
The program is developed in partnership with the Chinese Academy of Sciences and has researcher Xiyan XU as one of the responsible abroad and author of the work.
Sensitive balance of the ecosystem
The Amazon, as the largest and most biodiverse tropical forest in the world, has an important role in regulating the global climate. It is responsible, for example, for the so -called “flying rivers” – invisible water courses that circulate through the atmosphere and supply other biomes, such as the cerrado. The trees remove water from the soil through the roots, carry to the leaves and release it to the steam atmosphere.
At the end of last year, an international group of researchers, with the participation of Machado and the teacher, also of IF-USP, published a study in Nature showing, for the first time, the physicochemical mechanism that explains the complex rainfall system in the biome. It involves the production of nanoparticles of aerosols, electrical discharges and chemical reactions at high altitudes, which occur between the night and the day, resulting in a kind of “machine” of aerosols that will produce clouds.
However, deforestation and forest degradation processes contribute to the alteration of this cycle of rainfall, causing the intensification of the dry season on a local scale and increasing the periods of forest fires.
The Brazilian Amazon lost 14% of native vegetation from 1985 to 2023, according to data from, reaching an area of 553,000 km2the equivalent to the territory of France. The pasture was the main cause in the period.
Even reaching the 2nd lowest level of deforestation from August 2024 to July 2025 (an area of 4,495 km²)the challenge has been to contain degradation, especially caused by fire.
The dry season, from June to November, is the period when the impacts of deforestation are more pronounced, especially on rain. The cumulative effects intensify more seasonality.
DISCOVING THE DATA
To reach the results, scientists worked with surface parametric equations considering both annual and deforestation variations. Allowed to separate specific contributions from global climate change and vegetation loss. They also used remote sensing data sets and long -term reanelis, including land use classifications produced by Mapbiomas.
In addition to the findings related to rain and temperature, the group analyzed greenhouse gas data. Concluded that, over the 35th anniversary, the increase in the₂ (carbon dioxide) and CH₄ (methane) was driven practically by global emissions (over 99%). An increase of about 87 ppm (parts per million) was observed for₂ and about 167 ppb (parts per billion) to ch₄.
Environmental data, atmospheric changes and land coverage of approximately 2.6 million km² in the Brazilian Legal Amazon in a period of 35 years (1985 to 2020) were analyzed in a period of 35 million (1985 to 2020)
“At a first moment, this result seemed antagonistic with other articles showing the impact of deforestation on the reduction of the forest’s ability to remove CO₂ from the atmosphere. But it is not because the concentration of CO₂ is something large. In those were local CO₂ flow measurements. When it comes to concentration, the increase is predominantly due to global emissions.”says Machado.
In the article, the researchers warn that if deforestation remains without control, the extrapolation of the results suggests an additional decline in total precipitation during the dry season and higher temperature rise.
Recent studies indicate that deforestation in the Amazon is already changing the standards of the South American monsoon (climate phenomenon that brings abundant rainfall to downtown and southeastern Brazil during summer), resulting in drier conditions that can compromise the long-term resilience of the forest. Extreme events, such as the droughts of 2023 and 2024, only aggravate the situation.
Click to read the article “How climate change and deforestation interact in the transformation of the Amazon rainforest”.
With information from.
