The latest sea-level rise "report cards" by Virginia researchers show that ocean levels are continuing to rise and in some cases, including along the North Carolina coast, are speeding up.
Data released by William & Mary and the Virginia Institute of Marine Science in May reinforced the trend of sea-level rise that has been occurring along the U.S. East and Gulf coasts for decades.
Researchers use information from more than 30 tide gauge sites scattered around the U.S. coast. Using tidal observations since 1969, the Virginia Institute has been analyzing tide-gauge data to forecast possible sea-level rise out to 2050. Gauges the researchers track in the Southeast include Norfolk, Virginia, Wilmington, Charleston, South Carolina, and Savannah, Georgia.
Dr. Molly Mitchell, research assistant professor at William & Mary and the Virginia Institute, said the 2024 data shows that sea-level rise in the Carolinas and Georgia is accelerating.
"It's not rising as fast as Norfolk is, but the rate of rise is speeding up in those areas,” she said.
Norfolk has the highest sea-level rise rate on the U.S. East Coast, while the fastest rates of sea-level rise nationally are occurring along the Gulf coast in Louisiana and Texas.
Wilmington's sea-level rise "report card" projects that the Port City will see an average sea-level rise of 0.54 meters (1.77 feet) over 1992 levels by 2050. Wilmington's NOAA tidal gauge is at the base of the Cape Fear Memorial Bridge.
The annual rise rate in Wilmington is 3.59 millimeters (0.14 inches) per year. That compares to 4.26 mm in Charleston and 4.63 mm in Savannah. Norfolk's rate is 5.60 mm a year.
That doesn't sound like a lot. But Mitchell said the compound impact of rising waters year after year means those millimeters can quickly turn into centimeters and then meters.
"And we've seen sea-level rise and flooding accelerate in the last 15 years, and that means more 'sunny day' and non-storm related flooding events are impacting communities, especially along those flat and low-lying land areas where we've seen a lot of coastal development," she said.
A recent paper by researchers from N.C. State and the University of North Carolina at Chapel Hill determined that flooding events in coastal areas, including Carolina Beach, are occurring at a much higher rate than official tracking tools capture. The flooding also is lingering longer. Sea-level rise was stated to be one of the major factors contributing to the surge in non-storm flooding events.
'Cognizant about the future'
Sea-level rise is a natural phenomenon. But it is also an event that is being exacerbated by human actions, notably the pumping of greenhouse gases into the atmosphere that is, among other things, increasing the melting rate of the polar ice caps.
Scientists, including top researchers on the United Nations' Intergovernmental Panel on Climate Change said there is little doubt that humans are the leading cause of global warming, with sea-level rise a major symptom of climate change.
What has been supercharging the rising seas off the Carolinas and Georgia in recent years, however, still isn't entirely known. But Mitchell said there could be a range of large-scale factors impacting why that's happening, including increased ice sheet melting and changing circulation patterns − possibly involving the Gulf Stream.
But because the tide gauges reflect very local characteristics, rise rates also could be influenced by factors such as a change in water flows, drought, sinking land masses − a major problem in much of northeastern North Carolina − or other local climate and geological conditions.
This means the report cards can better reflect the experiences of the communities near the tide gauges. That, in turn, can allow for better long-term planning by residents and local leaders.
"This information hopefully will allow decision makers to think about how flooding has been in the past, how it is now, and how it will be in the future, and allow it to be factored into development choices moving forward," Mitchell said. "If we're cognizant about the future, we can hopefully make better choices and reduce the flood risk facing these communities."
Reporter Gareth McGrath can be reached at [email protected] or @GarethMcGrathSN on X/Twitter. This story was produced with financial support from the Green South Foundation and the Prentice Foundation. The USA TODAY Network maintains full editorial control of the work.