A recent study found that over the past 35 years, human activities such as dam construction and land reclamation have converted 250,000 acres of estuaries – approximately 17 times the size of Manhattan – into urban land or agricultural fields, with most of the land conversion occurring in rapidly developing countries. Estuaries are vital ecosystems that connect land and sea, providing habitat for wildlife, sequestering carbon, and serving as hubs for transportation and shipping. However, altering estuaries can lead to lower water quality, habitat fragmentation, and loss of coastline protection from storms.
The study, led by geoscientist Guan-hong Lee from Inha University in South Korea, emphasizes the significant impact human modifications have on estuaries, especially in the 20th century. Developed countries like the Netherlands and Germany have already experienced significant estuary modifications and losses, serving as a warning for developing nations. Lee suggests that conserving estuaries now presents an opportunity for developing countries to safeguard their environmental and economic benefits. The study was published in the AGU journal Earth’s Future, which focuses on interdisciplinary research concerning the past, present, and future of our planet and its inhabitants.
Using Landsat remote sensing data from 1984 to 2019, the researchers identified 2,396 large estuaries worldwide and tracked changes in estuarine surface area over time. They found that between 1984 and 2019, humans converted 1,027 square kilometers of estuaries to urban or agricultural lands through land reclamation, accounting for 20% of estuary loss. Globally, 44% of estuaries have been altered by dams and/or land reclamation. The study highlights the scale of estuary alteration and the significant impact it has on environmental health.
In analyzing the relationship between estuary gain or loss and economic development, the researchers compared countries’ gross income per capita to land reclamation and estuary area. They found that middle-income countries lost the most estuarine area during the study period, with almost 90% of land reclamation occurring in these nations as they transition to middle-income status. High-income countries, on the other hand, experienced minimal estuary loss in the study period, mainly due to earlier estuary alterations when they were developing or middle-income countries. These countries now focus on conservation efforts to undo the environmental damage caused by past estuarine development.
The findings underscore the opportunities that developing countries have to minimize the negative environmental and economic impacts of degraded estuaries while also addressing their economic and development needs. By learning from the experiences of high-income countries and taking proactive measures to conserve estuaries, developing nations can protect these vital ecosystems and ensure sustainable development for the future. The study provides valuable insights for policymakers and stakeholders working to balance economic growth with environmental conservation in regions vulnerable to estuary degradation.
