The Eastern Equatorial Atlantic includes many developing countries facing societal challenges that are intensified by climate variability and change. We highlight the key societal drivers affecting this region.

Rainfall variability linked to the tropical Atlantic strongly affects South America and West Africa, where the West African Monsoon is vital for water and food security. Accurate predictions across timescales—from weeks to decades—are crucial to support agriculture, manage water resources, protect infrastructure, and mitigate health risks from floods and droughts.

The second largest oceanic source of CO₂ to the atmosphere, after the tropical Pacific, is the tropical Atlantic. Air-sea CO₂ fluxes in this region exhibit strong interannual variability closely linked to climate variability. While uptake of anthropogenic CO₂ helps regulate atmospheric concentrations, it also causes ocean acidification, with significant but poorly understood impacts on marine organisms and ecosystems.

Oxygen minimum zones (OMZs) in the eastern tropical Atlantic, both shallow (∼100 m) and deep (∼400 m), result from high biological consumption and weak ventilation. The shallow OMZs intersect the euphotic zone, influencing ecosystems, carbon export, and air–sea fluxes of climate-relevant gases. Since the 1960s, the expansion of OMZs has affected fisheries, aquaculture, nutrient cycling, and climate.

Elevated productivity characterizes the tropical Atlantic, fueled by roughly 25% of global riverine freshwater from the Amazon, Congo, and Orinoco rivers, which supply high levels of nutrients to adjacent coastal waters. The region also hosts two major eastern boundary upwelling systems, the Canary and Benguela, supporting some of the world’s most productive fisheries.

Fisheries and seafood are vital for coastal communities around the tropical Atlantic, providing food and livelihoods. In 2016, about 10 million tons of seafood—out of 87.2 million tons globally—were harvested from the Central and South Atlantic. The region supports roughly 8 million fishers across Africa, Latin America, and the Caribbean, in addition to foreign fleets exploiting tropical Atlantic resources.

Ultimately, ecosystems in the eastern tropical Atlantic depend on nutrients, ocean biogeochemistry, and physical conditions. These systems are affected both by human pressures such as fishing and pollution, and by climate-driven changes including warming and deoxygenation. Rainfall variability also directly influences agriculture and food security, making it essential to monitor and understand both oceanic and atmospheric responses.