Baseline time accounting: Considering global land use dynamics when estimating the climate impact of indirect land use change caused by biofuels

Abstract

Purpose Current estimations of the climate impact from indirect land use change (ILUC) caused by biofuels are heavily influenced by assumptions regarding the biofuel production period. The purpose of this paper is to propose a new method (baseline time accounting) that takes global land use dynamics into account that is consistent with the global warming potential, that is applicable to any phenomenon causing land use change, and that is independent of production period assumptions. Methods We consider ILUC in two forms. The first is called "accelerated expansion" and concerns ILUC in regions with an expanding agricultural area. The second is called "delayed reversion" and concerns ILUC in regions with a decreasing agricultural area. We use recent trends in international land use and projections of future land use change to assess how ILUC from biofuels will alter the development in global agricultural land use dynamics compared to the existing trend (i.e., the baseline development). We then use the definition of the global warming potential to determine the CO 2 equivalence of the change in land use dynamics.Results and discussion We apply baseline time accounting to two existing ILUC studies in the literature. With current trends in global agricultural land use, the method significantly reduces the estimated climate impact in the previous ILUC studies (by more than half). Sensitivity analyses show that results are somewhat sensitive to assumptions regarding carbon sequestration and assumptions regarding postreversion ecosystems. Conclusions The global dynamic development in land use has important implications for the time accounting step when estimating the climate impact of ILUC caused by biofuel production or other issues affecting land use. Ignoring this may lead to erroneous conclusions about the actual climate impact of ILUC. Several land use projections indicate that the global agricultural area will keep expanding up to and beyond 2050. We therefore recommend to apply the baseline time accounting concept as an integrated part of future ILUC studies and to update the results on a regular basis.

Baseline time accounting--reply to the letter to the editor of Martin [Int J Life Cycle Assess (2013) 18(7):1279]

“…After becoming aware of a letter to the editor from Martin (2013), we realize there is a need for further elaboration of the baseline time accounting method laid out in Kløverpris and Mueller (2013). In the following, we address Martin's comments.…”

“…For additional discussion, we refer to Sect. 4.1.2 in Electronic supplementary material 1 of Kløverpris and Mueller (2013), particularly.…”

“…More correctly stated, baseline time accounting converts a time shift in land use emissions from a single batch of biofuels into an ILUC factor that is consistent with the GWP concept, and the results presented by Kløverpris and Mueller (2013) are based on a GWP accounting period of 100 years. The chosen GWP accounting period ensures consistency with the common global warming metric used for greenhouse gas (GHG) emissions.…”

Accounting for effects of carbon flows in LCA of biomass-based products—exploration and evaluation of a selection of existing methods

“…The method development for assessing indirect land use change (e.g. Kløverpris and Mueller (2013), Schmidt et al (2015)) seems to have evolved in parallel to the UNEP-SETAC guideline , rather than directly from it. The methods developed in conjunction with the UNEP-SETAC guideline on global land use impact assessment are referred to as land use methods in this paper.…”

Regarding your article “Baseline time accounting: considering global land use dynamics when estimating the climate impact of indirect land use change caused by biofuels.” Int J Life Cycle Assess 18(2):319–330. doi: 10.1007/s11367-012-0488-6

“…The baseline time accounting paper of Kløverpris and Mueller (2013) provides an interesting perspective on an important issue, but the value of their insight is diminished by the failure to include a full consideration of the importance of the timeframe of the analysis. Their examples reevaluate analyses of two existing indirect land use change (ILUC) studies, both of which were based on a 30-year timeframe (Searchinger et al 2008;Hertel et al 2010).…”