Two billion people are threatened by land subsidence

In an era where nearly two billion people worldwide are threatened by land subsidence, understanding and addressing this geohazard has become a critical mission.

Land subsidence involves the sinking of the earth’s surface, triggered by a range of natural and human-induced factors. This process presents significant risks to urban infrastructure, agriculture, and the availability of water resources.

Natural vs. human factors

Subsidence can unfold in two distinct ways: it can strike suddenly or emerge gradually over years. This phenomenon is driven by a mix of natural events, such as earthquakes and volcanic activity, and human actions, including groundwater abstraction and mining.

Subsidence poses a significant challenge in densely populated areas. There, it can cause buildings to collapse and damage vital infrastructure. Such events not only endanger lives but also add complexity to the management of resources.

Furthermore, experts have identified groundwater abstraction as a primary catalyst for subsidence. This process involves actively removing water from underground reserves for both consumption and irrigation.

As water is extracted, the ground above it compacts, leading to sinking land. This connection between groundwater use and subsidence highlights the urgent need for careful water resource management.

AI-powered insights into subsidence

A recent study sheds new light on this issue. The research was led by Tsimur Davydzenka, a Ph.D. researcher at Colorado School of Mines, along with Dr. Pejman Tahmasebi and Professor Nima Shokri. The team utilized deep machine learning to predict global land subsidence impacts.

“Land subsidence is a destructive phenomenon that damages infrastructure and aquifers, as well as putting human lives at risk. Population growth has played an undeniable part in resource extraction that has led to subsidence,” noted the researchers.

The groundbreaking work has led to the creation of the world’s first global map of subsidence rates. This map serves as a vital tool, informing groundwater management policies and guiding efforts to mitigate subsidence.

Widespread impact of subsidence

The researchers conducted an extensive analysis of 46,000 subsidence scenarios, taking into account variables such as climate, geography, and soil composition.

Through rigorous examination, the team determined that over 6.3 million square kilometers of land are at significant risk of subsidence. This area is home to nearly 25% of the global population, highlighting the widespread impact of this issue.

Mitigation and adaptation strategies

The research also underscores the importance of reducing reliance on groundwater. Proposed strategies include enhancing water use efficiency, implementing stricter regulations, promoting water-smart agriculture, and investing in water recycling technologies.

Additionally, exploring alternative water sources like treated wastewater and rainwater harvesting could play a crucial role in sustaining water supplies without further depleting groundwater reserves.

The findings reveal that unconsolidated sediments are particularly vulnerable to subsidence, with cultivated lands being the most at-risk. Regions like South Asia face the highest threat, with millions of people potentially impacted.

Broader implications

The research serves a dual purpose: it aids in the planning and preparedness of communities affected by subsidence and lays the groundwork for refining predictive models. These improved models will help local authorities develop targeted strategies for mitigation, enhancing the resilience of vulnerable areas.

The researchers noted that enhancing these models to capture details such as groundwater abstraction depth and the impact of industries will be vital in addressing the intertwined challenges of population growth, groundwater dependency, and climate change-induced droughts.

With land subsidence poised to remain a critical global issue, the integration of innovative research, strategic policy-making, and community engagement will be essential in safeguarding our future.

The study is published in the journal Geophysical Research Letters.

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