Climate change will lead to significant changes of groundwater recharge and thus renewable groundwater resources. Using the global water resources and use model WaterGAP, the impact of climate change on groundwater recharge and the number of affected people was computed for four climate scenarios by two climate models. Vulnerability of humans to decreased
groundwater resources depends on both the degree of decrease and the sensitivity of the human system to the decrease. For each grid cell, a sensitivity index composed of a water scarcity indicator, an indicator for dependence of water supply on groundwater and the Human Development Index was quantified.