Over 500 million people live in the world's river deltas, but many of these deltas are now at risk of sinking due to damming, mining and other causes. A new infographic produced by IGBP highlights the challenges.
The world’s deltas have been centres of population since ancient times. Our ancestors thrived along the banks of great rivers like the Nile, Indus and Yellow, whose fertile soils allowed crops to flourish, and whose channels and waterways transported people and goods, creating some of the world’s first trading ports.
Today, the relationship between humans and deltas has reversed: human society is shaping deltas. And as a result, some deltas are no longer thriving.
Deltas are naturally dynamic geological structures, formed when sediment is carried from upstream down to the coast. Although humans have actually boosted the growth of deltas in the past, as soil erosion from activities such as farming meant that more sediment was carried downriver, the activities of modern humans, such as building dams that stop flows of new sediment, have led to compacted soils – and to slowly sinking deltas.
This, combined with sea-level rise, has resulted in an increase in flooding from both rivers and the sea, causing risks to human life and livelihoods.