Today different regions must meet growing demand for land—most notably for food and bioenergy crops—amid changes in the local availability of fresh water. One approach is to boost crop yields through improvements in irrigation technology, but its implementation would require actionable estimates on the current scope of irrigated land and how much additional land can be irrigated, in what regions, and at what cost. To that end, this study develops a framework to more accurately represent the value of irrigated crop production and the potential of irrigated land areas to expand within economy-wide, applied general equilibrium (AGE) models.

The researchers compute the value of production on irrigated and rainfed cropland at an approximately 10-square kilometer grid-cell level as well as for the 140 regions and eight crop sectors in Version 9 of the Global Trade Analysis Project (GTAP) Data Base. For each crop category, they estimate and compare the dollar-value of irrigated and rainfed crop production using estimates of production quantities and prices. To represent the potential of irrigated land areas to expand, the researchers use irrigable land supply curves for 126 water regions globally, based on water availability and the costs of irrigation infrastructure. These curves enable regions to adapt to changes in water resources and agriculture demand through irrigation technology and crop production intensification.

The researchers’ new framework allows for more rigorous integrated assessments of regional and global impacts of water availability on land use, energy production and economic activity. They make this user-customizable framework available to enable other researchers to make integrated assessments of the current production value and expansion potential of irrigated land.