Researchers report that large-scale commercial farms on deforested land in the Amazon are tied to higher temperature increases and less rainfall, compared with small-scale farms. Deforestation has converted swaths of land in the southern Amazon region from rainforest to farmland. The uses of the deforested land are diverse, and activities can range from small-scale farming in rural settlements to large-scale commodity agriculture. Eduardo Maeda and colleagues used satellite data to compare areas dominated by different land uses and farm sizes to evaluate impacts on the regional climate. Although rural settlements experienced no clear changes in seasonal rainfall between 1998 and 2014, commodity farms experienced decreasing rainfall rates, likely due to a reduction in convective rainfall. Deforested lands dominated by commodity farms experienced an increase in surface temperature between 1.57 and 3.06 °C--higher than areas occupied by small-scale rural settlements, which experienced temperature increases between 1.05 and 1.85 °C, largely due to intense management of commercial crops leading to reduced vegetation cover throughout the year and decreased plant transpiration. According to the authors, mitigating climate change in the Amazon basin will require alternatives to current commodity farming practices.
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Article #20-23787: "Large-scale commodity agriculture exacerbates the climatic impacts of Amazonian deforestation," by Eduardo Eiji Maeda et al.
MEDIA CONTACT: Eduardo Eiji Maeda, University of Helsinki, FINLAND; email: < eduardo.maeda@helsinki.fi >
Proceedings of the National Academy of Sciences