East Coast sea levels rising at the fastest rate in 2,000 years

Along much of the U.S. Atlantic coast, the rate of sea-level rise in the 20th century was the highest it has been in the last 2,000 years, according to a new study from Rutgers University. The fastest rate of sea-level rise was found in southern New Jersey.

Rising ocean temperatures and melting ice cover caused a global rise in sea levels from 1900 to 2000 that more than doubled the average for the years 0 to 1800.

The experts analyzed the factors that contributed to ocean level changes over 2,000 years at six sites along the East Coast based on a sea-level budget. 

The researchers explained that sea-level budget assessments quantify the different physical processes contributing to sea-level change. These processes include global fluctuations in ice cover, regional changes such as land subsidence, and local factors such as groundwater withdrawal.

Study lead author Jennifer S. Walker is a postdoctoral associate in the Department of Earth and Planetary Sciences in the School of Arts and Sciences at Rutgers University-New Brunswick. 

“Having a thorough understanding of sea-level change at sites over the long-term is imperative for regional and local planning and responding to future sea-level rise,” said Walker. “By learning how different processes vary over time and contribute to sea-level change, we can more accurately estimate future contributions at specific sites.”

Sea-level rise linked to climate change threatens to permanently inundate low-lying islands and coastal areas. Rising sea levels also make these regions more vulnerable to flooding and damage from storms.

The goal of the Rutgers study was to better understand how the processes that affect sea levels have changed and how they could shape future changes. The sea-level budget method used for the analysis could be applied to other sites around the world.

The researchers used a statistical model to develop sea-level budgets for six sites, dividing sea-level records into global, regional and local components. The experts determined that regional land subsidence, or sinking land, has dominated the budget of each site over the last 2,000 years. 

Regional and local processes, such as groundwater withdrawal, were found to contribute much less to each budget and vary over time.

The total rate of sea-level rise for each of the six sites in the 20th century ranged from 2.6 to 3.6 millimeters per year – the fastest changes in the sea level in 2,000 years. Southern New Jersey had the fastest rates, with over 1.6 millimeters a year measured at Edwin Forsythe National Wildlife Refuge in Atlantic County and 1.5 millimeters a year at Cape May Court House.

The study is published in the journal Nature Communications.

–—

By Chrissy Sexton, Earth.com Staff Writer