East Coast of US at greater risk of flooding – thanks to ‘dangerously weak’ current of

Science

America’s East Coast is predicted to experience rising sea levels in the coming decades, but a new discovery could accelerate the timeline.

Researchers at the University of Miami found a critical ocean current that brings cool water to the North Atlantic from around Antarctica slowed by 12 percent from 2000 to 2020 to rise by – but predicts it could drop to 15 percent by 2050.

The weakening current – called the abyssal limb – is part of the Atlantic Meridional Overturning Circulation (AMOC), a system of ocean currents that act as a ‘conveyer belt’ to distribute heat, nutrients, and carbon dioxide across our oceans.

Because cooler water is not flowing abundantly to the North Atlantic, ocean temperatures will rise and cause water to expand – putting millions of Americans at risk of coastal flooding.

America’s East Coast is predicted to experience rising sea levels in the coming decades, but a new discovery could accelerate the timeline. Pictured is Seaside Park, New Jersey as Storm Ophelia hit in 2023

Tiago Bilo, lead author of the study, said in a statement: ‘Although this number might seem small, the areas affected by this warming span thousands of miles in the north-south and east-west directions in the deep sea (2.5 – 3.7 miles depth).

‘As a result, there is a significant increase in deep sea ocean heat content, contributing to local sea level rise due to the thermal expansion of the water.’

Biló continued to explain that the weakening from 2000 to 2020 increased sea levels by 2.8 millimeters.

Scientists have long studied AMOC due to fears it could collapse, but even weakening could alter weather patterns, impact marine life, change temperatures and increase flooding.

The current has different layers – upper, deep and abyssal – that move water across the world.

The upper layer transports warm water from the subtropical South Atlantic Ocean across the equator northward toward high latitudes in the North Atlantic, where it cools, sinks, and flows equatorward as cold deep water.

The abyssal limb carries denser water from the ice edge of Antarctica, which flows north along the seafloor into the North Atlantic where they slowly rise and mix with other waters that flow back to the south.

Scientists have long studied AMOC due to fears it could collapse, but even weakening could alter weather patterns, impact marine life, change temperatures and increase flooding

The deep sea current includes Antarctic bottom water (ABW), which forms from the cooling of seawater in the Southern Ocean around Antarctica during winter months.

ABW sinks to the ocean floor and moves up north, driving the AMOC’s abyssal limb.

The researchers partnered with the National Oceanic and Atmospheric Administration (NOAA) for the study, which was conducted using two decades of oceanographic data collected by observational mooring programs

A mooring is a collection of devices connected to a vessel and anchored on the sea floor.

The data allowed the team to see how the ABW being trapped around Antarctica could impact the North Atlantic Ocean.

‘Although these regions are tens of thousands of miles away from each other and abyssal areas are a few miles below the ocean surface, our results reinforce the notion that even the most remote areas of the world’s oceans are not untouched by human activity,’ said Biló.

Climate scientists have long been sounding the alarm on rising sea levels along the US East Coast.

The New York City Panel on Climate Change (NPCC) claimed in January that sea levels around New York City could rise by one-foot in the 2030s, triggering tropical storms and hotter temperatures.

NOAA found in 2022 that more than 56 million people living along the US east coast and Gulf of Mexico are predicted to experience at least 10 times the amount of high-tide flooding days by 2050 due to rising sea levels as a result of climate change