Thank you for visiting the New Hampshire Fish and Game Department website. NH Fish and Game



Rising Sea Levels

Rising Sea Levels and Climate Change


The levels of the earth’s oceans are rising. This is due to increasing global temperatures, which are also causing the ocean water to warm, and the warmer the water the more volume it takes up. Another cause of rising sea levels is the melting of mountain glaciers and the Antarctic and Greenland ice sheets. In coastal New Hampshire, relative sea level is likely to rise between 0.5 and 1.3 feet by 2050 and between 1.0 and 2.9 feet by 2100 if global greenhouse gas concentrations stabilize, according to a report by the New Hampshire Coastal Risks and Hazards Commission.


great bay

How Rising Sea Levels Are Affecting Wildlife


Rising sea levels lead to inundation of coastal habitats and cause saltwater to move into freshwater habitats creating a hostile environment for those species adapted to freshwater habitat only. Other coastal changes that may affect wildlife include lower ocean pH (acidification), deeper water, and increasing temperature and salinity (higher salt level). The rising waters will flood salt marshes and eelgrass beds, deepen estuaries, and convert marsh grass to mudflat and mudflats to subtidal zones. If the rate of sea level rise is rapid, affected habitats will be inundated more frequently, putting their associated species at high risk. Habitat and species losses are particularly likely near developed areas where there is less room for plants and animals to migrate inland naturally. If saltmarshes degrade or have nowhere to migrate to, there will be no place for saltmarsh sparrows to nest, as an example.


Dune and beach habitats are important for many seabirds, including the state-endangered piping plover. Sea level rise may affect habitat availability and the timing of nesting and migration for seabirds. The sand and sediment will wash out to sea, making dredging and beach, dune, and marsh nourishment more necessary to maintain vital habitats within bays and inlets. The degradation and loss of dunes and their associated plants will increase the impacts of storms and high tides further inland. Most intertidal species may shift to higher elevations but will be subject to more heavy surf during storms. Island-nesting birds may lose habitat or experience reduced productivity as a result of changes to available prey, affecting species such as common and roseate terns.


What NH Fish and Game Is Doing in Response to Rising Sea Levels


There are many projects happening at Fish and Game that have a component involving climate change action. One example related to sea level rise is the partnership which began in 2019 between the Great Bay National Estuarine Research Reserve (GBNERR) in Greenland, NH, part of New Hampshire Fish and Game, and the National Oceanographic and Atmospheric Administration (NOAA) Office of Coastal Management to map Great Bay marshes and obtain high-resolution elevation data of the landscape. This information will be used to assess areas in need of restoration, identify areas to protect land to allow marsh migration inland, to serve as a baseline for changes over time, and can be easily entered into models that predict the marsh’s future. GBNERR was designated as a place to study long-term trends in the estuary including physical trends, such as water chemistry and biological fluctuations.


Rising Sea Levels and People


Rising sea levels lead to more coastal flooding during storms, changes to groundwater salinity and groundwater levels, and threatens marine fish, bird, and wildlife populations and habitats. More intense storms, also a result of climate change, can cause more damage to coastlines already dealing with higher water levels. All of these changes have direct impact on people as well, including infrastructure damage, decreased recreational opportunities, and harm to some food sources such as oysters.


Taking Action

  • Learn about wetland restoration efforts in your area and get involved.
  • Plant more plants and trees, which help to soak up water and help keep soil from eroding, as well as removing carbon dioxide from the air.
  • Educate yourself and share your understanding with friends and family about how climate change affects wildlife and habitats.                                                       
  • Start planning now for good ecological health and get involved in your local community by addressing potential climate change issues in your town or region.                                                       
  • Support and volunteer for environmental and conservation organizations that address climate change impacts to wildlife and habitats.
  • Become a citizen scientist and help collect data on plants, wildlife, water, and weather.