Measuring Exposure and Vulnerability to Nigeria’s 2012 Floods: Views from the Ground and Views from the Sky

Abstract Floods are one of the most damaging natural hazards globally, but measuring local impacts is complicated by challenges in the measurement of flood incidence, especially in Global South contexts. This paper examines household-level exposure and vulnerability to the major 2012 floods in Nigeria and studies how sensitive estimates are to different approaches to flood measurement. We construct seven different measures of flood incidence from survey reports, flood databases, and satellite imagery, which capture both physical inundation and reported damages. We find limited cross-measure correlations in flood incidence, while exposure estimates range from 0.03 to 13% of the total country population and 2–38% of survey households. While we do not claim to estimate causal impacts, the measures also disagree on whether household flood exposure is associated with decreases in agricultural output during the affected growing season, with only survey-based measures showing significant—and large—average losses ranging between 20 and 60% of pre-flood levels. When combining multiple measures, our results show that agricultural losses are greatest for households reporting direct flood-related harvest losses in communities where floods are detected by different sources, suggesting that considering multiple sources of flood exposure may help to identify the worst-affected communities. We conclude with three recommendations for future research: (1) examine multiple metrics of flood exposure and understand what they measure and their pros and cons, (2) align the empirical strategy and interpretation of results with the specific nature of what a given flood metric captures, and (3) conduct sensitivity analyses on outcomes of interest.