In the Mekong Delta, a push to grow food with saltwater

For generations, farming in Viet Nam’s Mekong Delta has depended on a delicate bargain. The river flooded, retreated and flooded again, carrying freshwater and sediment across a flat landscape whose vast fields helped turn the country into one of the world’s leading rice exporters. Now, forces far beyond the iconic river mouth are rewriting the terms of that equilibrium. As sea levels rise, saltwater is reaching farther inland. Climate change is making familiar patterns of drought and flooding less reliable.Upstream dams have sharply reduced the sediment carried down the Mekong, depriving the delta of material that replenishes its soils and helps its coastline keep pace with the rising sea. And now El Niño threatens to intensify the strain.Vietnamese authorities warned this summer that the climate phenomenon could bring prolonged heat, reduced rainfall and worsening saltwater intrusion, potentially threatening hundreds of thousands of acres of rice in the Mekong Delta. For Jack O’Connor, a marine ecologist at the United Nations University’s Institute for Environment and Human Security in Bonn, the delta offers a glimpse of a question that coastal communities around the world increa...