William & Mary 's Batten School & VIMS have released their 2024 U.S. sea level "report cards," providing updated analyses of sea level trends and projections for 36 coastal communities. Encompassing 55 years of historical data, the report cards aid planning and adaptation efforts by analyzing rates of sea level rise and acceleration at each locality and forecasting 2050 water levels.
This year, the report cards are consolidated in an interactive dashboard and add data from tide gauge stations in Annapolis, MD; Solomons Island, MD; Yorktown, VA; and Fort Myers, FL.
Most sea level projections are based on an understanding of average global sea level rise. However, sea levels do not rise uniformly across the world. Factors such as geological uplift, land subsidence, ocean currents and other processes all impact regional sea level trends.
"Many people who live near the coast want to know what they can reasonably expect over the next few decades, giving them time to make actionable plans and decisions," says Molly Mitchell, an assistant professor at the Batten School of Coastal & Marine Sciences & VIMS. "Compared to other predictions based on satellite data and global computer models, our reports are created using observed tide gauge data from the past 55 years and reflect the exact experience at the location of the gauge. The annual release of the report cards allows coastal regions to examine if past trends are changing and alter their planning accordingly."
The reports group localities into East Coast, Gulf Coast, West Coast and Alaskan Coast regions. Each report card shows values for monthly sea level averages along with high-and low-water levels caused by storms and other transient events, as well as a decadal signal showing the influence of longer-term climate patterns such as El Niño. Observed rates of acceleration are factored into future projections and are displayed in comparison to a linear trendline that does not account for acceleration.
The projections also show the range of sea level rise within the 95% confidence interval, which allows individuals and municipalities to plan adequately for the highest predicted rates of sea level rise caused by things like storm surge and tidal flooding.
Overall, most locations continue a trend of accelerating sea level rise. However, Mitchell notes that projections have remained mostly uniform since reporting began in 2018, apart from a few notable exceptions.
"One interesting new trend is the acceleration occurring in southeastern states such as South Carolina and Georgia," said Mitchell. "We continue to see the fastest rates of sea level rise in Gulf states like Texas and Louisiana, but many of the East Coast stations are accelerating quite quickly, likely due to patterns of water distribution related to glacial melt from the Greenland ice sheet."
Mitchell also notes that most West Coast localities have been fairly stable, despite past predictions that they would increase rapidly. "This has led to some questions about why," she said.
Information about the processes most affecting regional sea levels is listed on the Batten School & VIMS website .
Emeritus Professor John Boon launched the sea level report cards in 2018 following the publication of the study Anthropocene Sea Level Change: A History of Recent Trends Observed in the U.S. East, Gulf and West Coast Regions , which showed a notable increase in sea level acceleration rates beginning in 2013-2014.
