Research shows that one-fifth of the world's estuaries have disappeared in the past 35 years

Recent research shows that nearly half of the world's estuaries have been changed by humans and 20% of estuaries have disappeared in the past 35 years, especially in Asian countries.

Estuaries – where rivers meet the sea – are often called 'the nursery of the sea'. This is the birthplace of many fish species and home to many bird species. Salt marshes around estuaries also help stabilize the coast and prevent flooding.

A fishing boat moves at the mouth of the Yellow River, Shandong province, China. (Photo: Guardian).

However, a new study shows that nearly half of the world's estuaries have been altered by humans and 20% of estuaries have disappeared in the past 35 years.

Using satellite data, researchers measured changes that occurred in 2,396 estuaries between 1984 and 2019.

Results published in the journal Earth Future show that, over the past 35 years, more than 100,000 hectares of estuaries have been converted to urban or agricultural land, with the majority of the loss (90%) occurring in developing countries in Asia.

In contrast, very little estuary loss has occurred in high-income countries over the past 35 years, largely because of widespread estuary change that occurred decades ago, during period of rapid development of those countries themselves.

Many high-income countries are now realizing and repairing the damage from this. For example, the UK has invested in the Tees estuary to return the area to mudflats and salt marshes, reducing the risk of flooding, increasing resilience to the climate crisis, and replenishing populations fish, and let nature recover.