Carbon Stocks in Sugarcane Biomass and Their Implications on Land Use Change CO2 Balance in Brazil

Abstract

Bioenergy represents a promising solution for mitigating climate change with sugarcane representing the most important feedstock in Brazil. However, its cultivation has raised concerns regarding direct land use change (DLUC), from which greenhouse gas (GHG) emissions can significantly alter its potential as a renewable energy source. Given its relevance for Brazil's energy transition strategy, this study aimed to derive more representative and regionalized estimates of carbon stocks in sugarcane biomass in Brazil. Impacts on carbon balance from DLUC associated with sugarcane cultivation over a 20-year period were evaluated. An extensive literature review was conducted to compile a dataset of sugarcane biomass parameters that compose the carbon pools and represent Brazil's current sugarcane production system. The main outcome is a sugarcane biomass' carbon factor (CFSUG) of 0.133 (±3.8%). It enables flexible and straightforward estimation of sugarcane carbon stock by multiplying by yield, that captures spatial and temporal variability. Using a 10-year average yield, the mean biomass carbon stock is 9.9% ± 4.1% MgC.ha−1 at national-level, over 100% higher and more accurate than IPCC's 4.7% ± 75%. The DLUC CO2 balance associated with sugarcane for 2000–2019 was negative, indicating net carbon removal, with an average of −4.8 TgCO2.year−1 (−9.1 to −0.5). The proposed CFSUG led to carbon removal in 62% of the sugarcane-producing municipalities, compared to 37% in previous studies that used standard values. The use of CFSUG in DLUC CO2 balance is recommended since they are more precise and representative of Brazilian conditions and can support more well informed GHG inventories and bioenergy policies worldwide.