Human activities such as groundwater removal and other natural causes are leading to the sinking of the Earth’s surface and the phenomenon will affect 635 million people, mostly in Asia, with a total exposed Gross Domestic Product (GDP) of $9.78 trillion in the next four years, warn researchers. By 2024, 19 per cent of the world’s population – accounting for 21 per cent of the global GDP — will be impacted by subsidence, the sinking of the ground’s surface, said the study published in the journal Science.

According to EurekAlert, The areas most likely to sink are concentrated in and around densely populated, urban centers and highly irrigated areas, places where there are high levels of groundwater extraction. Among the areas worst hit will be Asia’s North China Plain; the Gulf of Mexico coastal plain; river deltas in Vietnam, Egypt, and the Netherlands; and inland sedimentary basins of Mexico, Iran, and the Mediterranean.

Lead researcher Gerardo Herrera Garcia and his team performed a large-scale literature review that revealed that during the past century, land subsidence due to groundwater depletion occurred at 200 locations in 34 countries. The team developed a model by combining spatial and statistical analyses that identified an area’s subsidence susceptibility based on factors like flooding and groundwater depletion caused by human activities.

During the next decades, factors including global population and economic growth, exacerbated by droughts, will probably increase land subsidence occurrence and related damages or impacts. “Policies that implement subsidence modeling in exposed areas, constant monitoring of high-risk areas, damage evaluation, and cost-effective countermeasures could help reduce the impacts of subsidence where it will hit hardest – namely, areas with increased population density, high groundwater demand, and irrigated areas suffering water stress,” the authors elaborated.