Building resilience in South and Southeast Asian mega-deltas

Tropical mega-deltas in South and Southeast Asia are large riverine landforms where sediment derived from the catchment reaches coastal areas and is deposited in vast amounts. Crucially, tropical mega-deltas comprise social–ecological systems, wherein human populations depend on riverine processes and dynamics for their livelihoods. Human occupants in turn influence the natural ecosystem through their activities. As home for nearly 250 million people and acting as important food producers for the region and globally, it is vital these social–ecological systems are resilient to climate change effects and rising human influences on the system. We use the transboundary Ganges-Brahmaputra-Meghna Delta in Bangladesh and India and the Red River Delta and the Mekong River Delta in Vietnam as case study examples to illustrate these intertwined complexities. We highlight four key questions that need addressing to determine trajectories of change and inform how more inclusive governance of these social–ecological systems can better be tackled to optimise mega-delta societal resilience.