Climate change-induced temperature rises can influence variables that contribute to flooding. Flooding risks can be exacerbated by atmospheric rivers, storm surges, and sudden snowmelt. According to new research, flooding can affect food security for over 5.6 million people in several African countries. The work comes at a time when floods have also devastated Pakistan, India, and large parts of the European Union and the United States.
“Our findings show that floods can impact food security both immediately and months after the flood event,” says Connor Reed, a former New York University Center for Data Science graduate student and lead author on the study, “The impact of flooding on food security across Africa,” which appears in the Proceedings of the National Academy of Sciences.
“In many flood events we assessed, there were substantial damages to infrastructure, croplands, and livestock, which compromised food production and access, as well as water resources and sanitation also critical to food security.”
In recent years, record rainfall and flooding have heightened awareness of the consequences for affected populations and highlighted the need for a better understanding of the magnitude of their destruction, particularly on populations’ food needs.
Reed, along with Sonali Shukla McDermid, an associate professor in NYU’s Department of Environmental Studies, and other colleagues examined more than a dozen countries in western, eastern, and southern Africa, including Nigeria, Niger, Kenya, Mozambique, and Malawi, among others, to gain detailed insights into the impact of flood disasters.
This research demonstrates how cross-disciplinary teams can produce exponential improvements in our understanding of societal problems. We knew flooding had downstream consequences, but this study clarifies and quantifies those consequences in ways that will benefit people and communities facing increasingly frequent severe weather events.Jeffrey Mantz
Over the studied period (2009-2020), the researchers examined how key flood characteristics, including location, duration, and extent, influence an independent food insecurity metric used by the USAID-created Famine Early Warning System: the Integrated Food Security Phase Classification (IPC) scale. IPC measures the severity of food insecurity using a five-point scale: minimal food security (IPC 1), stressed (IPC 2), emergency (IPC 3), crisis (IPC 4), and famine (IPC 5). The team measured the impact of flooding over extended periods of time using panel analyses.
The results showed that approximately 12% of those who experienced food insecurity in the studied areas had their food security status affected by flooding over the 2009-2020 period. These impacts included detrimental increases to food insecurity, as expected, but there were also some beneficial impacts that ameliorated food insecurity, depending on the time period and regional scale.
“Our results suggest that floods can have opposing effects on food security at different spatial scales, particularly at time periods after they occur,” says study co-author Weston Anderson, a research scientist at NASA Goddard Space Flight Center and the University of Maryland’s Earth System Science Interdisciplinary Center. “In a given year, excess precipitation may immediately lead to floods that destroy crops in a localized area while also being associated with beneficial growing conditions that boost crop production on the country-scale.”
However, the researchers caution that any positive effects from flooding are not guaranteed, and these findings highlight the importance of improved data collection on flood and food security for disaster response and climate adaptation planning.
“What we emphasize in particular is that flooding has significant but complicated impacts on food security at various times and spatial scales,” McDermid says. “However, this is largely understudied globally and thus poorly understood. Improving understanding of where, when, and how floods impact food security is critical, particularly for decision-makers in flood-prone rural areas that contribute to regional and global food supplies.”
Notably, the results also revealed that flooding significantly affects food security in highly localized and varied ways — as opposed to uniformly across entire countries. The researchers say this indicates that the relationship between flooding and food security is not due to country-wide dynamics (e.g., changes in food prices), but instead to context-specific impacts on food production (e.g., subsistence crop loss), food access (e.g., destruction of infrastructure or direct loss of livelihoods), and/or food utilization (e.g., water-borne diseases and sanitation deficiencies).
“Understanding flood impacts on food security is becoming increasingly important for the humanitarian community,” says co-author Andrew Kruczkiewicz of Columbia University’s International Research Institute for Climate and Society. “With the study’s findings, the humanitarian community will be in a better position to decide which actions to prioritize or deprioritize in the areas we studied, including anticipatory, preparedness, and response.”
“This research demonstrates how cross-disciplinary teams can produce exponential improvements in our understanding of societal problems,” says Jeffrey Mantz, program director for the National Science Foundation, which funded the study. “We knew flooding had downstream consequences, but this study clarifies and quantifies those consequences in ways that will benefit people and communities facing increasingly frequent severe weather events.”