Crop models are often used to project future crop yield under climate and global change and typically show a broad range of outcomes. To understand differences in modeled responses, we analysed modeled crop yield response types using impact response surfaces along four drivers of crop yield: carbon dioxide (C), temperature (T), water (W), and nitrogen (N). Crop yield response types help to understand differences in simulated responses per driver and their combinations rather than aggregated changes in yields as the result of simultaneous changes in various drivers. We find that models’ sensitivities to the individual drivers are substantially different and often more different across models than across regions. There is some agreement across models with respect to the spatial patterns of response types but strong differences in the distribution of response types across models and their configurations suggests that models need to undergo further scrutiny. We suggest establishing standards in model evaluation based on emergent functionality not only against historical yield observations but also against dedicated experiments across different drivers to analyze emergent functional patterns of crop models.

To satisfy increasing global agricultural demand, the expansion of irrigation is an important intensification measure. At the same time, unsustainable water abstractions and cropland expansion pose a threat to biodiversity and ecosystem functioning. Irrigation potentials are influenced by local biophysical irrigation water availability and competition of different water users. Because water abstractions for various human uses along the river divert the river flow, it is also important to consider competing water uses when estimating irrigation potentials. Using a novel river routing routine that considers economic criteria of water allocation via a productivity ranking of grid cells and both land and water sustainability criteria, we estimate global irrigation potentials at a halfdegree spatial resolution. We show that there are considerable potentials to expand irrigation without harming the environment, but not necessarily at the places where irrigation is taking place today. In terms of potentially irrigated areas on current cropland, 711 Mha could be sustainably irrigated when only considering biophysical criteria. Of these, only 254 Mha have a yield value gain of more than 500 USD/ha and would be economically viable to be irrigated. The open-source data processing routine is a valuable aggregation and disaggregation tool for the use of hydrological inputs within land-system models that do not have a highly resolved representation of land use. The potentials can be aggregated to different simulation level units (e.g. basin level or country level) while maintaining biophysical and economic consistency.