Integrated modeling of global change impacts on land and water resources

There is a common scientific understanding that global change impact analysis, mitigation, and adaptation require interdisciplinary work. Integrated modeling could help to address the challenges associated with the impacts of global change. Particularly, integrated modeling that takes feedback effects into account will allow for the derivation of climate resilient land use and land management. Here, we call for more of such integrated modeling work focusing on the interdisciplinary subject of water resources and land management. As a proof-of-concept, we tightly couple a hydrologic (SWAT) and a land use model (CLUE-s) and illustrate the benefits of this coupled land and water modeling framework (LaWaCoMo) with a scenario on cropland abandonment induced by water stress. As compared to standalone model runs of SWAT and CLUE-s for the past, LaWaCoMo performs slightly better regarding measured river discharge (PBIAS: +0.8% and +1.5% compared at two gauges) and land use change (figure of merit: +6.4% and +2.3% compared to land use maps at two points in time). We show that LaWaCoMo is suitable for global change impact analysis as it is sensitive to climate and land use inputs as well as to management decisions. Our results shed light on the importance of feedback effects between land use and hydrology to assess impacts of global change on land and water resources accurately and consistently. To facilitate that the developed methodology can serve as a blueprint for integrated modeling of global change impacts, we used two freely available models that belong to the most widely used models in their respective disciplines.