What is the main flood risk for millions in river deltas?

The main flood risk for millions in river deltas is now human-driven land subsidence, which is a greater threat than sea-level rise.

Why is land sinking faster than sea levels are rising?

Land is sinking faster than sea levels are rising primarily due to human activities like extensive groundwater extraction, reduced sediment flow from dams, and urban growth.

Can land subsidence be slowed or stopped?

Yes, land subsidence is a local process that can potentially be slowed or halted through measures such as regulating groundwater extraction, restoring sediment flows, and improved urban planning.

Home / Environment / Land Sinking Faster Than Seas Rise: New Flood Threat

Land Sinking Faster Than Seas Rise: New Flood Threat

28 Jan

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Summary

Human-driven land subsidence is now the main flood risk for millions.
Land is sinking faster than sea levels are rising in many deltas.
Groundwater extraction is a primary driver of accelerated land sinking.

Land Sinking Faster Than Seas Rise: New Flood Threat

A global study encompassing 40 major river deltas has identified human-driven land subsidence as the primary threat for millions facing coastal flooding. This sinking land is now a more significant risk than the sea-level rise long associated with climate change.

The research, published in Nature, utilized satellite data from 2014 to 2023. It found that every delta studied is experiencing subsidence, with over half sinking at an average rate exceeding 3 mm annually. In 13 deltas, including the Nile and Mekong, land is sinking faster than global sea levels are currently rising.

Human activities, particularly extensive groundwater extraction for urban and agricultural use, are accelerating this sinking process. Reduced sediment flow from dams and urban growth also contribute significantly. In many deltas, subsidence now contributes more to relative sea-level rise than ocean warming.