US East Coast land continues to sink, puts millions at risk: Study

New York, Jan 7 (IANS) The East Coast of the US continues to sink at an alarming rate and new research has found that up to 74,000 square kilometres of the Atlantic Coast are exposed to "subsidence" of up to 2 millimeters (0.079 inches) a year, affecting up to 14 million people and more than 6 million properties.

Moreover, 3,700 sq. kilometers along the Atlantic Coast are sinking more than 5 millimeters annually -- faster than sea-level rise which is currently at 4 millimeters a year, reports Ars Technica, citing the study published in the journal PNAS Nexus.

“Major cities such as New York, Baltimore and Norfolk are exposed to subsidence rates between 1 and 2 mm per year. Additionally, our analysis indicates a notable trend: as subsidence rates increase, the extent of area exposed to these hazards correspondingly decreases,” the authors noted.

With each millimeter of subsidence, it gets easier for storms to enter in lands, causing widespread damage.

“It’s not just about sea levels. You also have potential to disrupt the topography of the land, for example, so you have areas that can get full of flooding when it rains,” said Leonard Ohenhen, study’s lead author and an environmental security expert at Virginia Tech.

“By quantifying the exposure to subsidence hazards for coastal communities and infrastructure, this study found that subsidence rates of 2 mm per year affects a maximum of 2.1 million people, 867,000 properties (median exposure), and significant infrastructure on the East Coast.

“This hazard is a major threat to metropolitan cities such as New York, Baltimore, and Norfolk, whose populations and properties intersect directly with the rising seas. Our study provides important quantitative data for coastal disaster resilience planning,” the authors noted.

The analysis has far-reaching implications for community and infrastructure resilience planning, emphasising the need for a targeted approach in transitioning from reactive to proactive hazard mitigation strategies in the era of climate change, they noted.