GCAM 3.0 Agriculture and Land Use: Data Sources and Methods
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PNNL-21025 Prepared for the U.S. Department of Energy under Contract DE-AC05-76RL01830 GCAM 3.0 Agriculture and Land Use: Data Sources and Methods P Kyle B Emanuel P Luckow M Nathan KV Calvin Y Zhou December 2011 DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor Battelle Memorial Institute, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. 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(9/2003) PNNL-21025 GCAM 3.0 Agriculture and Land Use: Data Sources and Methods P Kyle B Emanuel P Luckow M Nathan KV Calvin Y Zhou December 2011 Prepared for the U.S. Department of Energy under Contract DE-AC05-76RL01830 Pacific Northwest National Laboratory Richland, Washington 99352 GCAM 3.0 Agriculture and Land Use Modeling: Data Sources and Methods Page Kyle, Patrick Luckow, Katherine Calvin, William Emanuel, Mayda Nathan, and Yuyu Zhou Abstract This report presents the data processing methods used in the GCAM 3.0 agriculture and land use component, starting from all source data used, and detailing all calculations and assumptions made in generating the model inputs. The report starts with a brief introduction to modeling of agriculture and land use in GCAM 3.0, and then provides documentation of the data and methods used for generating the base-year dataset and future scenario parameters assumed in the model input files. Specifically, the report addresses primary commodity production, secondary (animal) commodity production, disposition of commodities, land allocation, land carbon contents, and land values. 3 Table of Contents 1 Introduction to Agriculture and Land Use in GCAM 3.0 ........................................... 5 2 Commodity Production ............................................................................................... 7 2.1 Primary Commodities .......................................................................................... 7 2.1.1 Agricultural Commodities ............................................................................ 7 2.1.2 Forest Products............................................................................................ 10 2.1.3 Pasture ......................................................................................................... 11 2.1.4 Purpose-grown biomass .............................................................................. 11 2.2 Secondary (Animal) Commodities ..................................................................... 14 3 Disposition of Commodities ..................................................................................... 14 3.1 Disposition of Primary Commodities ................................................................. 14 3.1.1 Net Exports ................................................................................................. 15 3.1.2 Food ............................................................................................................ 15 3.1.3 Feed ............................................................................................................. 16 3.1.4 Biofuels ....................................................................................................... 18 3.1.5 Other Uses ................................................................................................... 20 3.2 Disposition of Secondary (Animal) Commodities ............................................. 20 3.3 Final Demands of Commodities ......................................................................... 21 3.3.1 Food Demand: Crops .................................................................................. 21 3.3.2 Food Demands: Meat .................................................................................. 21 3.4 Non-Food Demands for Crops, Meat, and Forest Products ............................... 22 4 Land Use ................................................................................................................... 22 4.1 Land Allocation .................................................................................................. 23 4.1.1 Cropland ...................................................................................................... 23 4.1.2 Urban Land ................................................................................................. 25 4.1.3 Tundra, Rock/Ice/Desert ............................................................................. 25 4.1.4 Managed Forest ........................................................................................... 25 4.1.5 Managed Pasture ......................................................................................... 26 4.1.6 Unmanaged Forest, Unmanaged Pasture, Grassland, Shrubland ................ 27 4.2 Carbon Contents ................................................................................................. 27 4.2.1 Vegetation carbon contents ......................................................................... 27 4.2.2 Soil carbon contents .................................................................................... 29 4.2.3 Physical and Economic Accounting for the Carbon Content in Biomass Energy 33 4.2.4 Land Values and Land Sharing Logit Exponents ....................................... 34 5 References ................................................................................................................. 35 6 Appendix A: Mapping lists ....................................................................................... 40 4 1 Introduction to Agriculture and Land Use in GCAM 3.0 This report provides an overview of the data processing methods used in the generation of the input data set to the agricultural and land use components of GCAM 3.0, including references to all source data used, as well as assumptions, calculations, and methods used to generate the model inputs. The current section provides a brief overview of the context of the agriculture and land use components of the model; more comprehensive documentation can be found in Wise and Calvin (2011). What primarily distinguishes GCAM 3.0 from previous versions is the ability to run the model with variable-length time steps, and the sub-regionalization of land use. While shorter timesteps can be used to capture desired near-term dynamics (e.g. policies with a specified start year), GCAM is still typically used as a long run model—running a century in 5-year steps. While the sub-regional representation of land use substantially changes the data read into the model, in terms of the overall modeling approach, the changes to this component should be considered evolutionary rather than an abrupt departure from previous versions. However, these changes, by design, do bring about a substantial increase in the ability to model crops and land use decisions and implications in much more physical, technological, and spatial detail, while still maintaining tight integration with the rest of GCAM. In the core version of GCAM 3.0, the model data for the agriculture and land use parts of the model is comprised of 151 subregions in terms of land use, based on a division of the extant 18 types of agro-ecological zones (AEZs), which are derived from work performed for the GTAP project (Monfreda et al, 2009), within each of GCAM’s 14 global geo- political regions (see Figure 1.1). Within each of these 151 subregions, land is categorized into approximately a dozen types based on cover and use (see Figure 1.2). Three of these types—tundra, desert, and built-up land—are not considered available for any other uses. The remaining land types are all subject to land use change over time according to changes in future profit rates. The different land use types include several types with natural vegetation such as unlogged forests and ungrazed grasslands, as well as commercial forests, pastures, and croplands. Approximately twenty primary agricultural commodities (including five bioenergy crops) are currently modeled, with yields specific to each of the 151 subregions. The model is designed to allow specification of different options for crop management for each crop in each subregion,