Development aid mitigates the humanitarian impacts of climate-related disasters

Climate change is intensifying the frequency and severity of natural hazards such as floods, storms, droughts, and heatwaves—turning them into devastating disasters that disproportionately affect the world’s poorest populations. While high-income countries are responsible for the majority of greenhouse gas emissions driving these changes, low-income countries bear the greatest human costs. Limited resources, weaker infrastructure, and constrained institutional capacity make these regions especially vulnerable to rising climate risks. As a result, climate-related disasters not only destroy lives and livelihoods but also deepen existing global inequalities. Development cooperation is one of the key instruments through which high-income countries seek to address these disparities and strengthen resilience in vulnerable regions. However, despite its centrality in international climate and development policy, the empirical evidence on whether and how development aid reduces the human impacts of climate-related disasters remains limited and inconclusive. Addressing this question we conduct a global subnational cross-disaster analysis covering the period 1989–2018, integrating a novel meteorological hazard modeling approach with geo-coded data on development aid and disaster impacts. Drawing on the disaster impact framework, we conceptualize mortality outcomes as a function of hazard, exposure, and vulnerability. Development aid can reduce vulnerability by strengthening adaptive capacity, infrastructure, and governance, thereby lowering disaster mortality even when not explicitly targeted at disaster risk reduction. Importantly, unlike humanitarian aid, which is allocated post-disaster, development aid is typically disbursed in advance, potentially enhancing resilience before crises occur. Our empirical contribution lies in developing a harmonized, cross-hazard measure of meteorological hazard severity based on ERA5 reanalysis data, capturing maximum precipitation, temperature, and wind speed extremes at the subnational level. These data are merged with a newly geo-coded dataset of development aid disbursements by European and multilateral donors as well as China and India from the GODAD dataset. This enables the first systematic global test of how pre-disaster development aid affects mortality outcomes across storms, floods, droughts, and temperature extremes. Preliminary findings show that higher per capita development aid allocated to disaster-affected regions before the disaster significantly reduces subsequent mortality, particularly during severe events. This suggests that aid can indeed help offset global inequalities in disaster vulnerability—although its reach and impact remain uneven across regions. By linking climate injustice, disaster risk, and aid effectiveness, this study provides new empirical evidence for debates on global inequality and climate adaptation.