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Drivers of atmospheric CO2 concentration in southeast Brazil: Insights from land use change, vegetation, and climate factors

Published Article

Brazil

Publication date: April 1, 2025

File format: URL

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Rising atmospheric CO₂ demands better understanding of regional sources and sinks. Using OCO‑2 satellite data from 2015–2021, this study analyzes column‑averaged CO₂ (Xco₂) across Southeast Brazil and links its variability to vegetation activity, climate and land‑use change. After detrending global signals, Xco₂R shows clear seasonal cycles—highest in autumn–winter and lowest in spring–summer—opposite to SIF, GPP, precipitation and irradiation. A marked increase in Xco₂R appears after 2017, especially over forested areas experiencing deforestation. National GHG inventory data indicate that land‑use change explains roughly half of the annual Xco₂R rise. Results highlight vegetation’s key role in CO₂ absorption and identify deforestation as the dominant regional CO₂ source.

Subject Tags

  • Forest
  • Carbon storage
  • Climate impacts

Abstract

The atmospheric carbon dioxide (CO2) increase is one of the main causes of climate change and has been a global concern. Due to the world's necessity of understanding CO2 sources and sinks, satellites such as the Orbiting Carbon Observatory 2 (OCO-2) have been launched to monitor greenhouse gases (GHG). This study aimed to characterize the temporal variability and the main factors controlling (i.e., vegetation, climate and land use changes) the column-averaged atmospheric CO2 (Xco2) in Southeast Brazil (925 thousand km2) between 2015 and 2021. Xco2 was detrended by subtracting the world's trend to study regional features (Xco2R). The vegetation component was sampled through the Solar Induced Chlorophyll Fluorescence (SIF) and Gross Primary Production (GPP). As regards climate parameters, we used Precipitation (Prec) and Global Irradiation (Qg), while the Land Use Change (LUC) was characterized by using the land use classification maps available to the region. Xco2R follows a seasonal pattern of maximum averages during autumn-winter and minimum averages spring-summer, with the highest value observed in October 2021 (393.4 ± 1.26 ppm) and the lowest in April 2015 (389.37 ± 1.7 ppm). For the other variables, this seasonality is inverted which means those have negative linear correlations with Xco2R ranging from −0.35 to −0.6. We observed an Xco2R temporal increase trend since 2017 and this tendency is higher over forest areas which could be related to deforestation observed in the same period. In addition, the emission data from the national GHG inventory estimated an increase of CO2 emissions due to land use changes in the same period and was able to explain around 50 % of the annual Xco2R increase in Southeast Brazil. Thus, vegetation has an essential role in the Xco2R absorption, and especially the land use change and deforestation were the main CO2 sources to the atmosphere on a regional scale.

Citation

da Costa, L. M., de Mendonça, G. C., de Araújo Santos, G. A., Pacheco, F. A. L., de Souza Rolim, G., Panosso, A. R., & La Scala Jr, N. (2025). Drivers of atmospheric CO2 concentration in southeast Brazil: Insights from land use change, vegetation, and climate factors. Remote Sensing Applications: Society and Environment, 38, 101614. https://doi.org/10.1016/j.rsase.2025.101614

TNC Authors