Credit: Mapping Specialists

A stunning 12 million people could be displaced by flooding in Vietnam’s Mekong Delta within half a century, according to new research led by Philip Minderhoud, a geographer at Utrecht University in the Netherlands. Minderhoud and his colleagues arrived at that surprising conclusion after analyzing ground-based measurements of the Mekong’s topography that the Vietnamese government shielded from Western scientists  for years. The results, published today in Nature Communications, show the Mekong’s elevation over sea level averages just 0.8 meter, which is almost two meters lower than commonly quoted estimates based on freely available satellite data.

The ground-truthed projection more than doubles the number of Vietnamese living in low-lying areas that will be inundated by encroaching seas, with some underwater in only a few decades. And Torbjörn E. Törnqvist, a geologist at Tulane University, who was not involved with the study, says the implications extend beyond the Mekong to similarly threatened deltas throughout the developing world. “My hope is that these findings will wake people up to the fact that we’re dealing with […]