Increases in heat-trapping gases in Earth's atmosphere are reflected by accumulating heat energy and acidity in the ocean. These physical changes impact marine ecosystems and habitat. In turn, shifting distributions of species threaten fisheries, aquaculture, and tourism, and the people and communities who depend on them.

    Key points:

  • Climate-related changes in the ocean's physical and chemical properties affect marine life. Changes already underway could alter the base of the food web and eventually impact its higher levels.
  • Climate-related changes have been implicated in shifting abundances and distributions of some fish species. For several commercial fisheries, the latitude of successful catches is moving toward the poles.
  • Along with human activities that have degraded coastal and marine habitat over time, climate change has the potential to cause severe and wide-ranging impacts on habitat through changing temperatures, ocean acidification, different circulation patterns, and rising sea levels.
  • Aquaculture already supplies half of all seafood produced for human consumption. Projections show the impacts of climate change on aquaculture will vary with location.
  • Utilization of living marine resources brings more than $70 billion into the U.S. economy each year. Sustaining the fish and marine species that people depend upon for food and income requires management plans that take the multiple factors affecting these ecosystems into account.

The value of marine ecosystems

Oceans and coasts are among the nation’s most treasured and valuable resources. From fish and fisheries to whales, sea turtles, coral reefs, and oysters, many living marine resources and their habitats are at risk from a rapidly changing and variable climate.

Fishing boat on water in front of cliffs

A seiner fishing for salmon off the coast of Alaska.

Climate-related changes in ocean and coastal ecosystems—including warming oceans, rising seas, ocean acidification, and coastal droughts—are impacting marine resources and, in turn, the people, businesses, and communities that depend on them.

Changes in the planet’s climate and ocean systems affect jobs, impact economies, and disrupt traditional ways of life. There is much at risk. Nationally, ocean-related fisheries generate approximately $200 billion in sales and support 1.7 million jobs each year.

Graphs show average latitude of landed value for several fisheries moving northward over time

As ocean temperatures rise, some ocean species are shifting northward along U.S. coastlines. Over the past 40 years, the average latitude of landed value for several marine species has moved northward.

Anticipated consequences in the field of marine resources include changes to ecosystem productivity, species abundances, species distributions, and community interactions (including changes in predation or competition between species). Species distribution shifts associated with rising ocean temperatures are already being observed in many regions—such as off the coast of New England and the mid-Atlantic. 

Less mobile species, such as corals, are not able to migrate with changing conditions to find suitable habitat. If conditions become unsuitable, species will die off and no longer be a resource to help defend coastal communities from storms and inundation, or provide the foundation for tourism and recreation.

Businesses and communities dependent on particular fisheries and marine resources will need to find ways to adapt to the changes.

Given the pace and scope of climate-related changes in marine and coastal ecosystems, decision makers need easy access to better information on what is changing, what is at risk, and what actions to take to prepare for and respond to changing climate and ocean conditions. The tools and information provided here are intended to help people and communities take action to reduce climate-related impacts and increase resilience.

This section has been excerpted and abridged from the report Climate Change Impacts in the United States: The Third National Climate Assessment (Chapter 24: Oceans and Marine Resources).

Learn more

To learn more about the impacts of climate change and variability on marine ecosystems and resources, visit the subtopic pages:

Banner Image Credit
Scene from a survey dive near Catalina Island, just off the southern California coast. Photograph by Adam Obaza, NOAA Fisheries, CC BY-NC-ND 2.0, via Flickr
Last modified
19 August 2016 - 12:21pm