Projections of global warming in Africa are generally associated with increasing aridity and decreasing water availability. However, most freshwater assessments focus on single hydroclimatic indicators (e.g., runoff, precipitation, or aridity), lacking analysis on combined changes in evaporative demand, and water availability on land. There remains a high degree of uncertainty over water implications at the basin scale, in particular for the most water-consuming sector-food production. Using the Budyko framework, we perform an assessment of future hydroclimatic change for the 50 largest African basins, finding a consistent pattern of change in four distinct regions across the two main emission scenarios corresponding to the Paris Agreement, and the business as usual. Although the Paris Agreement is likely to lead to less intense changes when compared to the business as usual, both scenarios show the same pattern of hydroclimatic shifts, suggesting a potential roadmap for hydroclimatic adaptation. We discuss the social-ecological implications of the projected hydroclimatic shifts in the four regions and argue that climate policies need to be complemented by soil and water conservation practices to make the best use of future water resources.

Water harvesting has been widely applied in different social-ecological contexts, proving to be a valuable approach to sustainable intensification of agriculture. Global estimates of the potential of water harvesting are generally based on purely biophysical assessments and mostly neglect the socioeconomic dimension of agriculture. This neglect becomes a critical factor for the feasibility and effectiveness of policy and funding efforts to mainstream this practice. This study uses archetype analysis to systematically identify social-ecological regions worldwide based on >160 successful cases of local water harvesting implementation. We delineate six archetypal regions which capture the specific social-ecological conditions of the case studies. The archetypes cover 19% of current global croplands with hotspots in large portions of East Africa and Southeast Asia. We estimate that the adoption of water harvesting in these cropland areas can increase crop production up to 60–100% in Uganda, Burundi, Tanzania and India. The results of this study can complement conventional biophysical analysis on the potential of these practices and guide policy development at global and regional scales. The methodological approach can be also replicated at finer scales to guide the improvement of rainfed agricultural.

In African small-scale agriculture, sustainable land and water management (SLWM) is key to improving food production while coping with climate change. However, the rate of SLWM adoption remains low, suggesting a gap between generalized SLWM advantages for rural development across the literature, and the existence of context-dependent barriers to its effective implementation. Uganda is an example of this paradox: the SLWM adoption rate is low despite favorable ecological conditions for agriculture development and a large rural population. A systemic understanding of the barriers hindering the adoption of SLWM is therefore crucial to developing coherent policy interventions and enabling effective funding strategies. Here, we propose a cross-scale archetype approach to identify and link barriers to SLWM adoption in Uganda. We performed 80 interviews across the country to build cognitive archetypes, harvesting stakeholders’ perceptions of different types of barriers. We complemented this bottom-up perspective with a spatial archetype analysis to contextualize these results across different social-ecological regions. We found poverty trap, overpopulation, risk aversion, remoteness, and post-conflict patriarchal systems as cognitive archetypes that synthesize the different dynamics of barriers to SLWM adoption in Uganda. Our results reveal both specific and cross-cutting barriers. Ineffective extension services emerges as a ubiquitous barrier, whereas gender inequality is a priority barrier for large supported farms and farms in drier lowlands in northern Uganda. The combination of cognitive and spatial archetypes proposed here can help to overcome ineffective “one-size-fits-all” solutions and support context-specific policy plans to scale up SLWM, rationing resources to support sustainable intensification of agriculture.

In Uganda, upgrading smallholder agriculture is a necessary step to achieve the interlinked sustainable development goals of hunger eradication, poverty reduction and land degradation neutrality. However, targeting the right restoration practices and estimate their cost-benefit at the national scale is difficult given the highly contextual nature of restoration practices and the diversity of small-scale interventions to be adopted. By analyzing the context-specific outcomes of 82 successful case studies on different Sustainable Land and Water Management  (SLWM) in Uganda, we estimated that out-scaling of successful practices to 75% of agricultural land would require a one-time investment of US$ 4.4 billion from smallholders. The resulting crop production increase could generate US$ 4.7 billion every year, once the practices are fully operational. These results highlight the necessity, and profitability, of investing in smallholder farmers to achieve the SDGs in Uganda, as opposed to large-scale agricultural interventions that might not profit local communities. This study can guide the development of nation-wide programs to mainstream SLWM by targeting the most suitable practices and plan for adequate financial support from government, investors and international development aids to smallholder farmers.