New data for representing irrigated agriculture in economy-wide models

Abstract

We develop a framework to represent the value of irrigated crop production and the expansion potential of irrigated land within economy-wide models, providing integrated assessment capabilities for energy, land, and water interactions. Specifically, we compute the value of production on irrigated and rainfed cropland at both a 5 arcminute by 5 arcminute level (about 10 square kilometers) and for the 140 regions and eight crop sectors in Version 9 of the Global Trade Analysis Project (GTAP) Data Base. For each crop category, we estimate the shares of production on irrigated and rainfed land using estimates of production quantities and prices, compared to approximations based on output volumes used in the GTAP-Water Data Base. We construct a global dataset of evaluation metrics to identify region-crop combinations where there are large differences in irrigated production value shares based on direct calculation and approximated by output volumes. The scope to expand the amount of irrigated land and the cost of doing so is quantified through irrigable land supply curves for 126 water regions globally, based on water availability and the costs of irrigation infrastructure. We also make available our adaptable work stream to calculate crop production values and to estimate irrigable land supply elasticities for use in economy-wide models. Altogether, this work can enhance integrated assessment and economy-wide modeling by more accurately capturing the value of crop production and facilitating the representation of endogenous investment in irrigation infrastructure in response to changing water availability. These data and modeling contributions allow for a more rigorous exploration of the regional and global impacts of water availability on land use, energy production, and economic activity.