Greenhouse Gas Emissions from Biofuels’ Indirect Land Use Change Are Uncertain but May Be Much Greater than Previously Estimated

Plevin, Richard J.; O’Hare, Michael; Jones, A. D.; Torn, M. S.; Gibbs, Holly K.

doi:10.1021/es101946t

Cited by 373 publications

(320 citation statements)

References 19 publications

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“…It should be emphasized that all models here assume point estimates rather than distributions in carbon intensity. A number of studies suggest that these carbon intensities are highly uncertain (e.g., Plevin et al 2010).…”

Section: Contribution From Bioenergymentioning

confidence: 99%

Comparison of low-carbon pathways for California

et al. 2015

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Jurisdictions throughout the world are contemplating greenhouse gas (GHG) mitigation strategies that will enable meeting long-term GHG targets. Many jurisdictions are now focusing on the 2020-2050 timeframe. We conduct an inter-model comparison of nine California statewide energy models with GHG mitigation scenarios to 2050 to better understand common insights across models, ranges of intermediate GHG targets (i.e., for 2030), necessary technology deployment rates, and future modeling needs for the state. The models (not including the Wind-Water-Solar model) ; the transportation sector is decarbonized using a mix of energy efficiency gains and alternative-fueled vehicles; and bioenergy is directed almost exclusively towards the transportation sector, accounting for a maximum of 40 % of transportation energy by 2050. Models suggest that without new policies, emissions from nonenergy sectors and from high-global-warming-potential gases may alone exceed California's 2050 GHG goal. Finally, future modeling efforts should focus on the: economic impacts and logistical feasibility of given scenarios, interactive effects between two or more climate policies, role of uncertainty in the state's long-term energy planning, and identification of pathways that achieve the dual goals of criteria pollutant and GHG emission reduction.

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Section: Contribution From Bioenergymentioning

confidence: 99%

Comparison of low-carbon pathways for California

et al. 2015

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“…Biofuels involve complex, dispersed and dynamic supply chains linking feedstocks and land use to fuel products. Although land-use change is not the only uncertainty, its magnitude can be large enough to negate near-term benefits from biofuels that compete for land, undermining confidence in LCAbased policies (Plevin et al 2010). NRC (2011) concluded that the RFS may be ineffective for reducing GHG emissions because of large uncertainties including those surrounding land use.…”

Section: Limitations Of Closed Loop Accountingmentioning

confidence: 99%

Biofuel’s carbon balance: doubts, certainties and implications

DeCicco

2013

Climatic Change

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Liquid fuels will remain valued energy carriers well into any upcoming period when CO 2 reductions are sought. Biofuels are the presumed replacement for the petroleum-based transportation fuels that dominate liquid fuel use. Lifecycle analysis embeds a closed-loop model of biofuel-related carbon flows, making net CO 2 uptake an assumption to be refuted. However, evaluating net CO 2 uptake through dynamic industrial and agriforestry supply chains at real-world commercial scales is extremely difficult. All such estimates carry a great deal of doubt and cannot be verified empirically. A different perspective follows by anchoring analysis in the certainty that end-use CO 2 emissions from biofuels are essentially the same as those of the petroleum fuels they replace. A first-order model of the globally coupled bio-and fossil-fuel system reveals conditions for biofuel use to provide an atmospheric benefit. No benefit occurs in the energy sectors where biofuels are used, but rather must be found elsewhere in locations of carbon absorption or retention. The implication is that climate mitigation efforts should focus on such locations and include any mechanisms through which net uptake (an enhanced sink or verifiable offset) can be achieved by biological, chemical, geological or other means. Although biofuels can play a mitigation role when certain conditions are met, deemphasizing biofuel production in favor of terrestrial carbon management may offer more immediate and effective ways to counterbalance the CO 2 emitted when using carbon-based liquid fuels of any origin. Climate policies for transportation fuels should be reconsidered accordingly.

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“…Schematic showing fossil fuel and biofuel cycle emissions with fuel carbon (detailing fuel combustion, downstream in black). 5 Searchinger et al…”

Section: The Time Horizonmentioning

confidence: 99%

“…Among the considerations separating these different values of CI are the different time profiles of GHG emissions [54] and the asymmetry of the distribution of the CI value [5]. More generally, the uncertainty associated with all, or any, estimates of ILUC is not random, nor is any best distribution estimate centred at zero; biofuels policy should not implicitly act as though it is by 'ignoring' ILUC on grounds of uncertainty.…”

Section: Recommendationsmentioning

confidence: 99%

Accounting for indirect land-use change in the life cycle assessment of biofuel supply chains

Sanchez

Woods

Akhurst³

et al. 2012

J. R. Soc. Interface.

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The expansion of land used for crop production causes variable direct and indirect greenhouse gas emissions, and other economic, social and environmental effects. We analyse the use of life cycle analysis (LCA) for estimating the carbon intensity of biofuel production from indirect land-use change (ILUC). Two approaches are critiqued: direct, attributional life cycle analysis and consequential life cycle analysis (CLCA). A proposed hybrid 'combined model' of the two approaches for ILUC analysis relies on first defining the system boundary of the resulting full LCA. Choices are then made as to the modelling methodology (economic equilibrium or cause -effect), data inputs, land area analysis, carbon stock accounting and uncertainty analysis to be included. We conclude that CLCA is applicable for estimating the historic emissions from ILUC, although improvements to the hybrid approach proposed, coupled with regular updating, are required, and uncertainly values must be adequately represented; however, the scope and the depth of the expansion of the system boundaries required for CLCA remain controversial. In addition, robust prediction, monitoring and accounting frameworks for the dynamic and highly uncertain nature of future crop yields and the effectiveness of policies to reduce deforestation and encourage afforestation remain elusive. Finally, establishing compatible and comparable accounting frameworks for ILUC between the USA, the European Union, South East Asia, Africa, Brazil and other major biofuel trading blocs is urgently needed if substantial distortions between these markets, which would reduce its application in policy outcomes, are to be avoided.

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Greenhouse Gas Emissions from Biofuels’ Indirect Land Use Change Are Uncertain but May Be Much Greater than Previously Estimated

Cited by 373 publications

References 19 publications

Comparison of low-carbon pathways for California

Comparison of low-carbon pathways for California

Biofuel’s carbon balance: doubts, certainties and implications

Accounting for indirect land-use change in the life cycle assessment of biofuel supply chains

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