Contributions of the world's glaciers to the hydrological cycle in the 21st Century


Glacier melt water contributions to the global hydrologic cycle are a concern for all humans relying on this critical water supply. This melt water is used through direct consumption as well as indirect consumption by irrigation for crops. Additionally, the melt water reaching the oceans represents a direct input to sea level rise and therefore accurate estimates of this contribution have profound economic and geopolitical implications. It has been demonstrated that, on the scale of glacierized river catchments land surface hydrological models can successfully simulate glacier contribution to streamflow. However, at global scales, the implementation of glacier melt in hydrological models has been rudimentary or non-existent. In this study, a global glacier mass balance model is coupled with the University of New Hampshire Water Balance/Transport Model (WBM) to assess recent and project future glacier contributions to the hydrological cycle on global scale. The glacier model computes monthly glacier mass changes and resulting runoff at the glacier terminus of each individual glacier from globally complete Randolph Glacier Inventory including ~ 200,000 glaciers. The time series of glacier runoff is aggregated over each grid cell and delivered to WBM and routed downstream. WBM tracks and uses the in-stream water for filling reservoirs, transfers of water between drainage basins, and irrigation along the global system of rivers with net discharge to the ocean. Climate scenarios from global climate models prepared for IPCC AR5 are used to explore the expected range of possible future glacier melt variability to estimate the impacts on human use of these valuable waters and their net contribution to sea level change.


Earth Sciences, Earth Systems Research Center

Publication Date


Journal Title

Fall Meeting, American Geophysical Union (AGU)


American Geophysical Union Publications

Document Type

Conference Proceeding