At the heart of the vision of sustainable development and intergenerational responsibility lies the prudent use of natural resources. Agriculture is a key sector both in terms of resources consumed and of goods and services provided. Recently Its intensification and expansion have been studied and their sustainability evaluated, often with a particular focus on water management. While, in literature, possible agricultural strategies have been based on local water availability and, in some cases, downstream effects of such strategies have been evaluated, a method to identify and quantify hydrologically sustainable land use and crop use changes directly accounting for downstream effects is yet to be defined. Here we propose a framework to assess hydrological sustainability of land use and crop use changes, preventing both in situ and downstream effects. We apply this framework on the case study of coffee plantations expansion in Kenya, a sector that is seeing, and is planned to see, a rapid growth, given its potential in promoting agricultural, economic, and social development, not without risks associated to hydroclimatic change. We simulate the hydrological alterations caused by coffee plantation expansion onto available suitable areas, and use these simulations to identify areas where the expansion does not generate water scarcity either in situ or downstream. The assessment of hydrological suitability proves effective in preventing water availability reduction. Areas selected for expansion present similar total water footprints as currently used areas, but with higher precipitation-generated water availability. The proposed methodology identifies and quantifies areas in a physically robust, and thus transparent, way, also maintaining flexibility to the selected expansion scenario and low data intensity. This makes this framework a potentially easily replicable methodology for planning sustainable agricultural development within planetary boundaries.

Climate change can potentially drive variations in the frequency and magnitude of hydrological extremes, and in turn the impact these events have on agriculture. Agricultural damages resulting from extreme events can significantly affect food security at multiple scales, especially in contexts where pre-existing unfavourable social and economic conditions already hinder the stability and the effectivity of the food supply chain. In these contexts, formulating approaches to directly quantify food security impacts of extreme events in a way that is compatible with local data availability, but at the same time reliable and transparent, becomes a crucial and urgent matter. Moreover, while the importance of the multifaceted repercussions of agricultural damage on food security have been highlighted in the current literature, investigation on impacts different than reduced crop availability remain understudied. Here, we propose a methodology to derive metrics of food availability and food access impacts from post-disaster assessments, by putting the affected communities at the core of the analysis. We then provide perspectives on food utilization and food stability impacts. We apply the methodology on the severe floods that affected Malawi in the early months of 2015. We find that agricultural losses correspond to food sufficient for feeding more than 300,000 people and for balancing the diet of almost 2.3 million. Food security impacts also appear to disproportionately hit poorer and less food-secure districts. The proposed methodology is easily replicable in other case studies, also moving beyond floods as the triggering extreme event.