Greenhouse Gas Assessment of Sugarcane-Based Ethanol Considering Direct Land Use Change and Its Cultivation in Brazil.

Abstract:

Inventorying greenhouse gas (GHG) emission associated to sugarcane-based ethanol is critical to assess the degree of carbon-neutrality of biofuels. Most studies on GHG emission have been conducted in relation to sugarcane production. Only a few studies have accounted for C emissions while taking direct land use change (dLUC) into account (Fargione et al., 2008). Thus, this study was conducted to enhance scientific understanding of the GHG balance related to sugarcane cultivation while considering dynamics of all C pools (biomass and soil) upon conversion of diverse land uses into sugarcane during 2006-2011 in the south-central of Brazil. Based on a comprehensive evaluation of survey data and given that the sugarcane cultivation and dLUC can be credibly assessed by using remote sensing satellite images (Aguiar et al., 2011; Adami et al., 2012), estimations of GHG emissions were performed using the IPCC (2003; 2006) methodologies and expressed in terms of Tg CO₂eq considering a 20-year time horizon. The overall accumulated GHG balance was 205.2 Tg CO₂eq by 2030, with an emitted amount of 481.6 Tg CO₂eq from sugarcane cultivation being offset by a biomass C sink of -274.5 Tg CO₂eq. Also, soils had an almost neutral C budget with a slight accumulation of -1.9 Tg CO₂eq by 2030. The data suggest that the impact of dLUC on biomass and soil C pools must be taken into consideration while expanding the area under sugarcane plantation as another mechanism for GHG abatement beyond the avoided emissions through use of biofuels.

Keywords: bioenergy, life cycle assessment (LCA), inventory, LUC, climate change.

 

References:

Adami, M., Rudorff, B.F.T., Freitas, R.M., Aguiar, D.A., Sugawara, L.M., 2012. Remote Sensing Time Series to Evaluate Direct Land Use Change of Recent Expanded Sugarcane Crop in Brazil. Sustainability 4, 574-585.

Aguiar, D.A., Rudorff, B.F.T., Silva, W.F., Adami, M., Mello, M.P., 2011. Remote Sensing Images in Support of Environmental Protocol: Monitoring the Sugarcane Harvest in São Paulo State, Brazil. Remote sensing 3, 2682-2703.

Fargione, J., Hill, J., Tilman, D., Polasky, S., Hawthorne, P., 2008. Land Clearing and the Biofuel Carbon Debt. Science 319, 1235-1238.

IPCC, 2003. Good Practice Guidance for Land Use, Land-Use Change and Forestry (GPG-LULUCF). In: Penman et al. (Eds.), IPCC National Greenhouse Gas Inventories Programme. Institute for Global Environmental Strategies (IGES), Hayama, Japan, pp. 1.1-5.1.

IPCC, 2006. IPCC Guidelines for National Greenhouse Gas Inventories. In: Eggleston et al. (Eds.), IPCC National Greenhouse Gas Inventories Programme. Institute for Global Environmental Strategies (IGES), Hayama, Japan, p. 664.