Indirect land-use changes can overcome carbon savings from biofuels in Brazil

TLDR

The planned expansion of biofuel plantations in Brazil could potentially cause both direct and indirect land‑use changes, such as biofuel plantations replacing rangelands, which in turn replace forests. The study projects land‑use changes from Brazil’s biofuel expansion using a spatially explicit model, assuming a 35‑fold increase in ethanol and biodiesel production between 2003 and 2020, and recommends stronger collaboration between the biofuel and cattle‑ranching sectors to achieve effective carbon savings. The authors used a spatially explicit model to simulate land‑use changes and tested alternative biodiesel feedstocks, finding oil palm would generate the least land‑use change and carbon debt. Simulations show direct land‑use changes have a small carbon impact, but indirect changes—especially Amazonian deforestation driven by rangeland expansion—could offset biofuel carbon savings, with projected indirect deforestation of 121,970 km² by 2020 creating a carbon debt that would take ~250 years to repay; oil palm feedstock would minimize this debt, and increasing livestock density could mitigate indirect land‑use changes.

Abstract

The planned expansion of biofuel plantations in Brazil could potentially cause both direct and indirect land-use changes (e.g., biofuel plantations replace rangelands, which replace forests). In this study, we use a spatially explicit model to project land-use changes caused by that expansion in 2020, assuming that ethanol (biodiesel) production increases by 35 (4) x 10(9) liter in the 2003-2020 period. Our simulations show that direct land-use changes will have a small impact on carbon emissions because most biofuel plantations would replace rangeland areas. However, indirect land-use changes, especially those pushing the rangeland frontier into the Amazonian forests, could offset the carbon savings from biofuels. Sugarcane ethanol and soybean biodiesel each contribute to nearly half of the projected indirect deforestation of 121,970 km(2) by 2020, creating a carbon debt that would take about 250 years to be repaid using these biofuels instead of fossil fuels. We also tested different crops that could serve as feedstock to fulfill Brazil's biodiesel demand and found that oil palm would cause the least land-use changes and associated carbon debt. The modeled livestock density increases by 0.09 head per hectare. But a higher increase of 0.13 head per hectare in the average livestock density throughout the country could avoid the indirect land-use changes caused by biofuels (even with soybean as the biodiesel feedstock), while still fulfilling all food and bioenergy demands. We suggest that a closer collaboration or strengthened institutional link between the biofuel and cattle-ranching sectors in the coming years is crucial for effective carbon savings from biofuels in Brazil.