Food insecurity is a key barrier to improving global health and achieving sustainable development. Nearly 30% of the world's population experiences moderate or severe food insecurity, and rates of hunger have risen in recent years. Environmental change is a major factor driving this increase, as warming air and water temperatures, extreme weather, and land use change can threaten food production. We argue that an important, yet underexplored, pathway between environmental change and food insecurity is through aquatic conditions and fisheries. We focus on Malawi, which is heavily dependent on fish consumption and experiences high rates of food insecurity. By linking nationally representative household survey data from 2010 through 2020 to remotely-sensed chlorophyll and lake surface temperature data from Lake Malawi, we examine the relationship between changing aquatic conditions and food security among households located near the lakeshore. We find that warmer-than-average lake temperatures are negatively associated with multiple food security indicators including Food Consumption Score, self-reported adequacy of food consumption, consumption of dried fish, and consumption of animal protein during four of more days in the prior week. These findings provide insight into the linkages between environmental change, aquatic conditions, and population health, and can inform policies to reduce food insecurity, particularly among fisheries-dependent communities.

Keywords: Climate change; Fisheries; Food security; Lakes; Land use change; Malawi.