We are beginning to see climate-related impacts in many national marine sanctuaries and in the surrounding communities. The impacts include the following. For more information on climate science, visit climate.gov.
Rising Sea Level
The melting of ice sheets and glaciers, combined with the thermal expansion of seawater as the ocean warms, is causing sea level to rise. Seawater is increasingly flooding low-lying land, submerging coastal habitats, facilities, and roads, and contaminating coastal freshwater habitats and sources. Sea level rise increases the risk of damage to homes and buildings from storm surges, such as those that accompany hurricanes.
- Rising sea level will encroach upon shorelines, narrowing beaches, increasing erosion, and affecting coastal ecosystems in our national marine sanctuaries, including nesting habitat for seabirds and marine mammal haul-out sites.
- Rising sea level may damage docks, boat houses, and other coastal structures, as well as those owned and operated by individuals and companies that use sanctuary resources (e.g., fishermen, whale watch companies, divers).
- Coastal flooding from rising sea level mobilizes pollutants and fertilizers that drain into the ocean, creating harmful algal blooms and ocean dead zones.
Ocean’s Influence on Weather and Climate
Covering 70 percent of Earth’s surface, the ocean exerts major control on climate by dominating Earth’s energy and water cycles. It absorbs vast amounts of solar energy. Heat and water vapor are redistributed globally through ocean currents and atmospheric circulation. Changes in ocean circulation caused by movements in Earth’s crust or large influxes of fresh water from melting polar ice can lead to significant and even abrupt changes in climate, both locally and on global scales.
- Increased storm frequency and intensity, coupled with higher wave heights, are increasing impacts to national marine sanctuary habitats, coastal infrastructure, and communities.
- Changes in upwelling regimes have large biological effects on national marine sanctuaries along the West Coast of the United States. Persistent and warmer sea surface temperatures could lead to long-term changes in the magnitude and timing of ocean upwelling.
- The direct and indirect effects of climate change on oceanographic processes, such as ocean circulation, are already affecting marine and coastal ecosystems.
Ocean acidification changes the chemistry of the ocean and has been called “osteoporosis of the sea.” It prevents some plants and animals at the base of the food web, as well as many larger organisms like shellfish and corals, from building and maintaining the protective skeletons or shells they need to survive. Ocean acidification also affects the behavior of marine organisms, such as settlement in corals and fish and the ability to locate prey in fish. This has the potential to fundamentally change marine ecosystems, food webs, and habitats globally, including national marine sanctuaries. Research provides a baseline for monitoring change in sanctuary ecosystems and will help us better understand and respond to these emerging threats. Learn more about ocean acidification and NOAA’s work to understand and address it here.
Changing Climate, Changing Species
Globally, species are on the move due to climate impacts. In the ocean, many species are moving toward the poles or into deeper water. In the Northeast Atlantic, for example, species have moved north and into deeper waters seeking preferred temperatures.