About 40% of global crop production takes place on irrigated land, which accounts for approximately 20% of the global farmland. The great majority of freshwater consumption by human societies is associated with irrigation, which contributes to a major modification of the global water cycle by enhancing evapotranspiration and reducing surface and groundwater runoff. In many regions of the world irrigation contributes to streamflow and groundwater depletion, soil salinization, cooler microclimate conditions, and altered land-atmosphere interactions. Despite the important role played by irrigation in food security, water cycle, soil productivity, and near-surface atmospheric conditions, its global extent remains poorly quantified. To date global maps of irrigated land are often based on estimates from circa year 2000. Here we apply artificial intelligence methods based on machine learning algorithms to satellite remote sensing and monthly climate data to map the spatial extent of irrigated areas between 2001 and 2015. We provide global annual maps of irrigated land at ≈9km resolution for the 2001-2015 and we make this dataset available online.

全球约40％的农作物产量来自灌溉土地，约占全球农田的20％。人类社会所消耗的大部分淡水与灌溉有关，它通过增加蒸散量并减少地表水和地下水的径流，对全球水循环做出了重大改变。在世界许多地区，灌溉导致水流和地下水耗竭，土壤盐碱化，微气候条件凉爽以及土地-大气相互作用的变化。尽管灌溉在粮食安全，水循环，土壤生产力和近地表大气条件方面发挥着重要作用，但其全球范围仍难以量化。迄今为止，全球灌溉土地图通常是基于大约2000年的估算得出的。