link to open access paper https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2025EF007585

Our key results first highlight the heterogeneous impacts of future uncertainties on security outcomes across sectors, regions, and income subgroups in 2050. For instance, the sub-populations with the lowest income in sub-Saharan Africa and India experience the highest food burden outcomes of nearly 50%. This is due to low regional income and high food prices that arise in scenarios with decreasing carbon and land conservation. On the other hand, the Middle East and South Africa emerge as regions with the highest residential energy burden for the lowest income group for different reasons: high demand for residential cooling and high shares of traditional fuels. Water scarcity challenges exist in South Asia, the Middle East, and Northern Africa due to rapid demand growth and extensive groundwater extraction. Across all sectors, we demonstrate that the regional average outcomes obscure both extremely high burden outcomes for lower-income subgroups and extremely low burden outcomes for higher-income subgroups. For instance, the range of food burden for Western Africa’s lowest income population extends from 18.5% to 77.5%, while the regional average only ranges between 5.4% and 24.0%. This emphasizes the importance of modeling sub-regional populations when considering resource security outcomes, which would be lost if only regional average outcomes were considered. Furthermore, the heterogeneous outcomes and impacts across sectors, regions, and income subgroups underscore the value of the multisectoral, exploratory modeling approach we adopt to model future resource security outcomes.

We further identify the key drivers of security outcomes across regions and quantify each driver’s relative contribution. In general, we find that socioeconomics (i.e., GDP, population, and income distributions), carbon intensity and land conservation scenarios, and consumer behavior assumptions heavily affect food and energy sector outcomes for the lowest income subgroup. Notably, scenarios with lower carbon may have an increased energy burden for the low-income population reliant on traditional carbon-intensive fuels (e.g., coal). Physical water scarcity outcomes are most strongly influenced by the reservoir expansion assumption across all regions. After that, uncertain factors affecting water supply (e.g., global runoff projections) and water demand (e.g., socioeconomics, carbon intensity and land conservation scenarios) affect the outcomes, depending on the region. Our results are consistent with other studies on future water scarcity considering global change (Birnbaum et al., 2022; Leijnse et al., 2024).