The flooding of Hampton streets has become part of life on the Seacoast. (Photo by Amanda Gokee/New Hampshire Bulletin)
As global temperatures climb and put increased pressure on shoreline communities, New Hampshire is reassessing its coastal flood risk.
That assessment is divided into two parts: a report on updated science coming late this spring, and guidance on how to use that science coming in spring 2026, the Department of Environmental Services said. The agency is required by law to update “storm surge, sea-level rise, precipitation, and other relevant projections” at least every five years.
Opportunities for public input and trainings will be posted on the project webpage, the department said.
The science report is a team effort involving “experts from the University of New Hampshire, the National Oceanic and Atmospheric Administration (NOAA), and other public and private organizations,” according to DES. That effort launched in November with the first meeting of the team, the department said.
In their latest report, in 2019, scientists said coastal flooding was already happening in the state and “is expected to increase in frequency and severity in the future.” One key finding was that “relative sea level in coastal New Hampshire is projected to rise for centuries.”
How a variety of decision makers – including government and corporate actors, property owners, and other affected parties – can use those scientific findings to prepare for the future was the focus of the latest guidance report in 2020. The document’s first guiding principle was to “support greenhouse gas reduction policies that avoid the worst coastal flood risks.” (New Hampshire has no statutory target to decrease greenhouse gas emissions, putting it at odds with climate plans in other New England states.)
The department plans to hold training sessions following the updated guidance report’s release in spring 2026. The work on that report is expected to begin this spring, DES said.
The state’s work comes as humanity reaches a crucial climate threshold. 2024 was the warmest year on record, and it was likely the first year where the global mean temperature surpassed 1.5 degrees Celsius above the 1850-1900 average, according to the World Meteorological Organization.
In the Paris Agreement – an international treaty signed by 195 parties – nations agreed to make efforts to limit global temperature rise to 1.5 degrees above pre-industrial levels, “recognizing that this would significantly reduce the risks and impacts of climate change.” Those impacts are especially acute for coastal communities and economies on the front lines of rising sea levels.
President-elect Donald Trump has said he would once again pull the United States from the agreement. The WMO said the temperature target was “not yet dead but in grave danger.”