Sea-level rises of about 1.5 feet by 2050 and of about 3.5 feet by 2100 are possible, researchers from Rutgers University and Tufts University reported Thursday.
By the middle of the century the one-in-10 year flood level at Atlantic City could exceed any flood known there from the observational record, including Superstorm Sandy, they said.
The researchers based their projections on historic and modern-day records of sea-level rise in the U.S. mid-Atlantic region.
"It's clear from both the tide gauge and geological records that sea level has been rising in the mid-Atlantic region at a foot per century as a result of global average sea-level rise and the solid earth's ongoing adjustment to the end of the last ice age," Rutgers earth and planetary sciences Professor Ken Miller said.
"In the sands of the New Jersey coastal plain, sea level is also rising by another four inches per century because of sediment compaction -- due partly to natural forces and partly to groundwater withdrawal.
"But the rate of sea-level rise, globally and regionally, is increasing due to melting of ice sheets and the warming of the oceans," he said.
That means greenhouse gas emissions are also a factor in rising sea levels, the researchers said.
"The geological sea-level records show that it's extremely likely that sea-level in New Jersey was rising faster in the 20th century than in any century in the last 4,300 years," said Tufts researcher Andrew Kemp.
An 8-inch climate change-related regional sea-level rise in the 20th century exposed about 83,000 additional people in New Jersey and New York City to flooding during 2012's Superstorm Sandy, the researchers said.