Estuaries have great ecological and economic value and sustain both population and economic growth. Global‐scale analyses suggest that human activities drive estuarine area change but these projections neglect direct human‐estuary interactions and socio‐economic feedbacks. Here, we quantified area changes of 2,396 estuaries in response to recent human impacts (e.g., land reclamation, estuarine dam construction) and economic development between 1984 and 2019, and find that estuarine area shrank by 5,372 km² whereas upland submergence created 5,015 km² of estuarine area elsewhere. Approximately 44% (n = 1,046) of today's estuaries have been directly altered through land reclamation, estuarine dam construction, or a combination of both, and ∼250,000 acres (1,027 km²) of estuarine area have been directly converted to urban or agricultural fields. Nearly 90% (923 km²) of land reclamation occurred in Asia linked to recent advances in economic development during the middle‐income stage. Additional historical mapping and 5‐year interval analyses revealed that while human alterations were insignificant during the low‐income stages, estuaries were predominantly altered during their middle‐income stages, where estuarine degradation is a common consequence of economic growth. However, this trend stabilizes in high‐income countries with the adaption of conservation laws and policies. Together, our results indicate that large‐scale estuarine loss can be avoided by preserving estuaries in low‐ and mid‐income countries in the early stages of economic development.