A review and synthesis of the Consultative Group on International Agricultural Research’s work on climate-induced extreme rainfall and floods, 2012–2023

Abstract

In recent decades, the increased frequency of extreme rainfall events has significantly affected agri-food systems, accounting for 19% of the total crop damage across the world and 18–43% of observed anomalies in global crop yields. Some studies indicate a global weighted mean rice yield loss of 9.0% by 2080 under a high-emissions scenario. In sub-Saharan Africa, crop yield losses from extreme rainfall can vary significantly, with one source citing a 33% reduction over the past 60 years due to climate-induced weather extremes, including floods. It is estimated that in Africa, about 12% of the people that experienced food insecurity from 2009 to 2020 had their food security status affected by flooding. The Sixth IPCC assessment report warns that climate change could push an additional 32–132 million people into extreme poverty by 2030 if the world does not immediately scale up adaptation solutions. This review articulates the CGIAR’s contribution to scientific knowledge on climate-induced extreme rainfall for the period 2012–2023. The review discusses research methods applied, main impacts of extreme rainfall on agri-food systems, and innovative adaptation solutions deployed. Out of 2846 identified papers, 73 studies met our search criteria and were included in the review. Our analysis reveals that the main impacts of extreme rainfall addressed by the CGIAR include physical loss of crops due to coastal area inundation, waterlogging, and salinity intrusion. Adaptation options that build the resilience of smallholder farming systems include scientific methods for forecasting changes in rainfall patterns; flood early warning systems; climate-smart agricultural technologies; flood-resilient seed varieties; and agroforestry. However, lack of finance and knowledge tends to limit smallholder farmers’ ability to adopt some of the technological innovations, suggesting the need for capacity building and policies for better access to microcredit, low-interest loans, and climate risk insurance schemes. Research gaps identified in the study call for the CGIAR to also focus on currently underexplored themes such as roots and tubers, livestock, fish, and peri-urban agriculture. The integration of attribution studies that address direct links between extreme rainfall and climate change could inform targeted interventions arising from CGIAR research. Studies that specifically quantify economic losses from floods could also generate important insights for effective agricultural investment and risk management. This review identifies key areas of focus and critical knowledge gaps to be addressed by future CGIAR research. It informs the agenda of decision makers and policy makers who grapple with the challenges of scaling adaptation solutions to strengthen farmers’ resilience to extreme rainfall.