Irrigation-expansion-induced impacts model-intercomparison project (IRRMIP)

Abstract

<p>As the most dominant freshwater-use practice, irrigation plays an important role in global and regional environmental changes. Its extent experienced a substantial increase during the 20<sup>th</sup> century, from less than 100 mha before 1950 to about 300 mha around the year 2000. To advance the scientific understanding of the irrigation-expansion-induced impacts during the last century, we launched a model-intercomparison project (MIP), through which we intend to discover its effects on different sectors, i.e. water, climate, and agriculture, with Earth system models. In the protocol, two experiments are designed, i) simulation with transient irrigation extent and ii) simulation with the irrigation extent fixed at the level of the year 1901. For every experiment, three ensemble members are required to reduce the uncertainty. Currently, the analysis of outputs will be focused on climate extremes, the water cycle, vegetation-carbon interactions and some social implications. In the next phase of IRRMIP, we plan to combine the Earth system model community with both the hydrological model and crop model communities.</p>