Biofuels and land-use changes: searching for the top model

Abstract

The use of agricultural-based biofuels has expanded. Discussions on how to assess green house gas (GHG) emissions from biofuel policies, specifically on (non-observed) land-use change (LUC) effects involve two main topics: (i) the limitations on the existing methodologies, and (ii) how to isolate the effects of biofuels. This paper discusses the main methodologies currently used by policy-makers to take decisions on how to quantify LUCs owing to biofuel production expansion. It is our opinion that the concerns regarding GHG emissions associated with LUCs should focus on the agricultural sector as a whole rather than concentrating on biofuel production. Actually, there are several limitations of economic models and deterministic methodologies for simulating and explaining LUCs resulting from the expansion of the agricultural sector. However, it is equally true that there are avenues of possibilities to improve models and make them more accurate and precise in order to be used for policy-making. Models available need several improvements to reach perfection. Any top model requires a concentration of interdisciplinary designers in order to replicate empirical evidence and capture correctly the agricultural sector dynamics for different countries and regions. Forgetting those limitations means that models will be used for the wrong purposes.

Climate policy scenarios in Brazil: A multi-model comparison for energy

“…Some models used in this study only account for direct emissions, while others have an endogenous land use model. Nevertheless, there are many uncertainties surrounding the methodologies in use today for life-cycle analysis of GHG emissions for land use change (Larson, 2006;Nassar et al, 2011). Calvin et al (in this issue) explores this complex issue in more detail in order to evaluate whether or not land use might influence the amount of mitigation required from the energy sector.…”

Biofuels and the Future of Food: Competition and Complementarities

“…The differences in how models handle trade also affects these results-as some models have a detailed bilateral representation of trade flows, such as in the GTAP models, versus a "pooling" of total net trade from all countries within an integrated world market, as is the case with many partial-equilibrium models. Indeed, there is a constellation of possible influences that could lead to these differences, which have been discussed in more detail by other authors [17,18] than we are able to do in this short paper. It is worth bearing these differences of measurement in mind when deciding how best to carry out ex ante environmental assessments of biofuels, and how to use them within the process of policy design or implementation.…”

Impact of agricultural-based biofuel production on greenhouse gas emissions from land-use change: Key modelling choices

“…Other authors have acknowledged the diversity of model-based results and the uncertainty linked to the estimation [7,17,19,22], and the current review is not needed as a contribution to that work. For this paper, the main factors influencing the measurement of LUC-GHG emissions from biofuel production have been studied, and previous reviews on the subject have been analysed, leading to the conclusion that a broader assessment of modelling approaches is needed to overcome current limitations.…”

“…Different approaches have been tried to isolate the effect of agricultural land expansion because such effects should be considered in the contexts of other relevant drivers of LUC. In this respect, previous assessments have already shown the limitation of current approaches for isolating the effects of the agricultural sector as a whole [22]. Assigning GHG emissions to biofuels requires the resolution of two fundamental problems: how to isolate the effect of crop-specific biofuels from other drivers of LUC, and how to deal with multi-product agricultural-based biofuels.…”