SIMPLE-on-a-Grid (SIMPLE-G) is a multi-region, partial equilibrium model of gridded cropland use, crop production, consumption and trade. It is an extension of the SIMPLE model that has been applied to study long run sustainability issues in the global food-water-environment nexus. Rather than looking at regions or country aggregates, SIMPLE-G divides the world into georeferenced grid-cell units. This allows SIMPLE-G to explicitly incorporate local environmental constraints in its projections, account for sub-national heterogeneity of global drivers such as climate change and water scarcity, and assess local land and water use given future trends the global farm and food system.

In SIMPLE, the world is split into sixteen economic regions. Regional consumption is disaggregated into four commodities (crops, livestock, processed foods and biofuels). Regional demand is driven by population, per capita income, and biofuel mandates (all exogenous in the model) as well as prices (endogenous to the model). SIMPLE-G extends the existing SIMPLE model by disaggregating rainfed and irrigated production and modeling these processes at the individual grid-cell level. Regional crop output is obtained by aggregating across the grid cells (30 arc-min resolution) within each region. Crop production follows a nested constant elasticity of substitution (CES) function. Water is an explicit input used by the irrigated sector only. Water consumption is computed as the product of gridded irrigated cropland area and a grid cell-specific consumptive water use parameter in m3/ha. By aggregating water use across grid cells within a sub-basin (defined below), we obtain total irrigation consumption. Water availability at each grid cell is exogenous in SIMPLE-on-a-Grid, and is obtained from the hydrological model. 

Researchers should cite this work as follows:

• Gaurav Sachdev; Jungha Woo; Lan Zhao (2023), "SIMPLE-G US Jupyter Notebook," https://mygeohub.org/resources/simplegus. (DOI: 10.21981/HGES-EM64).

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