The degradation of coastal habitats, particularly coral reefs, raises risks by increasing the exposure of coastal communities to flooding hazards during storms. The protective services of these natural defenses are not assessed in the same rigorous economic terms as artificial defenses, such as seawalls, and therefore often are not considered in decision-making.
The impacts of climate change and sea-level rise around the Pacific and Arctic Oceans can vary tremendously. Thus far the vast majority of national and international impact assessments and models of coastal climate change have focused on low-relief coastlines that are not near seismically active zones. Furthermore, the degree to which extreme waves and wind will add further stress to coastal systems has also been largely disregarded. By working to refine this area of research, USGS aims to help coastal managers and inhabitants understand how their coasts will change.
Why research on climate change and sea-level rise is important
Climate change and sea-level rise are already impacting coastal communities in many locations worldwide, including the U.S. west coast, Alaska, Hawaiʻi, and U.S. affiliated Pacific islands.
In the western tropical Pacific, elevated rates of sea-level rise (up to 1 centimeter/year) affect coastal infrastructure, freshwater resources, and terrestrial and marine ecosystems on U.S.-affiliated islands like the Marshall Islands, American Samoa, and the Northern Marianas. Alterations in storm patterns, contamination of freshwater aquifers by saltwater flooding, and permanent inundation by rising sea level—all fueled by climate change—threaten long-term human habitation on many of these atolls. Efforts to relocate coastal inhabitants from some low-lying Pacific Islands are already underway.
Along Arctic shores of Alaska, shoreline erosion and habitat loss are accelerating due to increasing permafrost thaw and sea ice forming much later in the year, leaving the coast more susceptible to waves and storm surge. Alaskan government agencies and land-use planners are relocating some Native Alaskan villages and critical airstrips farther inland from eroding shores, such as Kivalina on the northwestern coast.
The U.S. west coast is vulnerable as well. In California alone, roughly half a million people and $100 billion worth of coastal property are at risk during the next century. In highly developed coastal areas such as San Francisco Bay and Puget Sound, hundreds of millions of dollars are being spent on restoration of nearshore ecosystems, which protect shorelines from erosion by waves and provide habitat for socially and economically important species. But resource managers remain uncertain whether outcomes of these efforts will be resilient to projected sea-level rise.
Because the impacts of climate change and sea-level rise around the Pacific and Arctic vary considerably, no single solution can mitigate the impacts. Coastal communities, along with federal, state, and local managers, need better scientific information and tools to plan for the particular threats they may face from saltwater flooding, shoreline erosion, and habitat loss.
Historically, simple “bathtub” models of future sea levels have assumed a static coast—one that is neither subsiding nor rising, neither retreating nor growing seaward—and they calculate future flooding based on just sea-level rise and tides, ignoring the impacts of storms. Those models cannot adequately account for the diverse influences that affect most coasts, including sediment input, how the coast is shaped, and “forcings”—atmospheric and oceanographic conditions that force the environment to change (for example, wind and circulation patterns, wave heights and directions).
Thus, in tectonically active coastlines like the U.S. west coast, USGS seeks to develop models that incorporate sea-level rise projections combined with storm impacts, as well as potential changes in wave heights and storm patterns associated with climate change.
What the USGS is doing
We are developing rigorous research tools to understand the physical impacts that climate change and sea-level rise will have on dynamic geologic settings along Pacific and Arctic coasts. This research covers an enormous range of coastal settings: from permafrost coasts, to the Puget Sound estuary, the California coast, and low-lying Pacific atolls.
By understanding the effects of extreme storms, including coastal flooding, changes in the shoreline, and movement of sediment, we can develop better models for understanding long-term vulnerability of sea-level rise in various coastal settings, and help coastal managers and businesses plan for a changing climate.
Our areas of study include the following, with brief descriptions of each.
Climate impacts to Arctic coasts
The Arctic region is warming faster than anywhere else in the nation. Understanding the rates and causes of coastal change in Alaska is needed to identify and mitigate hazards that might affect people and animals that call Alaska home.
Low-lying areas of tropical Pacific islands
Sea level is rising faster than projected in the western Pacific, so understanding how wave-driven coastal flooding will affect inhabited, low-lying islands—most notably, the familiar ring-shaped atolls—as well as the low-elevation areas of high islands in the Pacific Ocean, is critical for decision-makers in protecting infrastructure or relocating resources and people.
Dynamic coastlines along the western U.S.
The west coast of the United States is extremely complex and changeable because of tectonic activity, mountain building, and land subsidence. These active environments pose a major challenge for accurately assessing climate change impacts, since models were historically developed for more passive sandy coasts.
Estuaries and large river deltas in the Pacific Northwest
Essential habitat for wild salmon and other wildlife borders river deltas and estuaries in the Pacific Northwest. These estuaries also support industry, agriculture, and a large human population that’s expected to double by the year 2060, but each could suffer from more severe river floods, higher sea level, and storm surges caused by climate change.
Climate impacts on Monterey Bay area beaches
For a beach town like Santa Cruz, preserving beaches by mitigating coastal erosion is vital. USGS scientists conduct regular surveys of the beaches in the Monterey Bay region to better understand the short- and long-term impacts of climate change, El Niño years, and sea-level rise on a populated and vulnerable coastline.
Collaborators
Collaborators include USGS Coastal and Marine Geology Program colleagues in Woods Hole, Massachusetts, and St. Petersburg, Florida, and researchers with the USGS Western Ecological Research Center on Mare Island, California. Academic collaborators include those from University of Hawaiʻi, Oregon State University, University of Alaska, University of California, Scripps Institution of Oceanography, and University of Cantabria (Spain). Also involved are colleagues and federal partners from such agencies as the U.S. National Park Service, U.S. Fish and Wildlife Service, U.S. Department of Defense, and National Oceanic and Atmospheric Administration.
Below are all of the research topics associated with this project.
Dynamic coastlines along the western U.S.
Low-lying areas of tropical Pacific islands
Climate impacts to Arctic coasts
Using Video Imagery to Study Coastal Change: Santa Cruz Beaches
Climate impacts on Monterey Bay area beaches
Coastal Storm Modeling System (CoSMoS)
Using Video Imagery to Study Wave Dynamics: Unalakleet
Using Video Imagery to Study Coastal Change: Sunset State Beach
Using Video Imagery to Study Sediment Transport and Wave Dynamics: Nuvuk (Point Barrow)
Estuaries and large river deltas in the Pacific Northwest
Coastal Change Hazards
Below are data releases associated with this project.
Ocean wave time-series data simulated with a global-scale numerical wave model under the influence of historical and projected CMIP6 wind and sea ice fields (ver. 2.0, October 2024)
Model parameter input files to compare the influence of channels in fringing coral reefs on alongshore variations in wave-driven runup along the shoreline
Wave model results of the central Beaufort Sea coast, Alaska
Modeled extreme total water levels along the U.S. west coast
Model parameter input files to compare locations of coral reef restoration on different reef profiles to reduce coastal flooding
California shorelines and shoreline change data, 1998-2016
A GIS compilation of vector shorelines and coastal bluff edge positions, and associated rate-of-change data for Barter Island, Alaska
Modeled 21st century storm surge, waves, and coastal flood hazards and supporting oceanographic and geological field data (2010 and 2011) for Arey and Barter Islands, Alaska and vicinity
Projected responses of the coastal water table for California using present-day and future sea-level rise scenarios
Coral reef profiles for wave-runup prediction
Model parameter input files to compare wave-averaged versus wave-resolving XBeach coastal flooding models for coral reef-lined coasts
Physics-based numerical model simulations of wave propagation over and around theoretical atoll and island morphologies for sea-level rise scenarios
Below are multimedia items associated with this project.
The degradation of coastal habitats, particularly coral reefs, raises risks by increasing the exposure of coastal communities to flooding hazards during storms. The protective services of these natural defenses are not assessed in the same rigorous economic terms as artificial defenses, such as seawalls, and therefore often are not considered in decision-making.
Barter Island sits at the top of the Arctic National Wildlife Refuge in Alaska, and with the Arctic facing quickly rising temperatures, USGS wants to investigate what’s causing the North Slope bluffs to erode so quickly.
Barter Island sits at the top of the Arctic National Wildlife Refuge in Alaska, and with the Arctic facing quickly rising temperatures, USGS wants to investigate what’s causing the North Slope bluffs to erode so quickly.
This time-lapse of Barter Island in Alaska during three summer months in 2014, shows the pack ice melting and the subsequent effects to the beach and permafrost cliffs from storms and summer temperatures. This camera sat on a fallen snow fence to capture storm events.
This time-lapse of Barter Island in Alaska during three summer months in 2014, shows the pack ice melting and the subsequent effects to the beach and permafrost cliffs from storms and summer temperatures. This camera sat on a fallen snow fence to capture storm events.
Below are publications associated with this project.
A numerical study of geomorphic and oceanographic controls on wave-driven runup on fringing reefs with shore-normal channels
Characterizing storm-induced coastal change hazards along the United States West Coast
Global and regional sea level rise scenarios for the United States
Digital Twin Earth - Coasts: Developing a fast and physics-informed surrogate model for coastal floods via neural operators
Projecting climate dependent coastal flood risk with a hybrid statistical dynamical model
Assessment of barrier island morphological change in northern Alaska
Drivers of extreme water levels in a large, urban, high-energy coastal estuary – A case study of the San Francisco Bay
Multiple climate change-driven tipping points for coastal systems
Global-scale changes to extreme ocean wave events due to anthropogenic warming
Twenty-first-century projections of shoreline change along inlet-interrupted coastlines
The value of US coral reefs for flood risk reduction
The application of ensemble wave forcing to quantify uncertainty of shoreline change predictions
Below are data releases associated with this project.
Future Coastal Flooding
Prediction of Flooding Now and Into the Future: a geonarrative on coastal storms
Coastal Change in Alaska
Alaska's north coast has been home to indigenous communities for centuries. Changing coastlines threaten important infrastructure and historic sites that support indigenous communities. Changing coastlines also can potentially reduce habitat for Arctic wildlife, such as polar bears, shorebirds, and walruses. Oil- and gas-related development sites and U.S. Department of Defense installations
The Role of U.S. Coral Reefs in Coastal Protection
U.S. Geological Survey scientists have shown that along with providing food, tourism, and biodiversity, coral reefs also protect dollars and lives. This interactive geonarrative introduces the USGS research to understand the role of US coral reefs in coastal protection.
National Shoreline Change
Exploring Shoreline Positions of the United States From the 1800s To The Present. This geonarrative explains how the USGS derives shorelines from various data sources, and how shoreline change rates are generated from these data. The Natural Hazards Mission Area programs of the USGS develop and apply hazard science to help protect the safety, security, and economic well-being of the Nation.
Real-Time Forecasts of Coastal Change
U.S. Geological Survey researchers develop tools to forecast coastal change hazards. This geonarrative features research and tools developed to forecast real-time coastal change.
Our Coasts
USGS Coastal Change Hazards research provides scientific tools to protect lives, property, and the economic well being of the Nation. The mission of the USGS Coastal Change Hazards Program is to provide research and tools to protect lives, property, and the economic well-being of the Nation. This is a story map that introduces the value of our coasts and the threats they face with global change.
Below are news stories associated with this project.
Below are partners associated with this project.
The impacts of climate change and sea-level rise around the Pacific and Arctic Oceans can vary tremendously. Thus far the vast majority of national and international impact assessments and models of coastal climate change have focused on low-relief coastlines that are not near seismically active zones. Furthermore, the degree to which extreme waves and wind will add further stress to coastal systems has also been largely disregarded. By working to refine this area of research, USGS aims to help coastal managers and inhabitants understand how their coasts will change.
Why research on climate change and sea-level rise is important
Climate change and sea-level rise are already impacting coastal communities in many locations worldwide, including the U.S. west coast, Alaska, Hawaiʻi, and U.S. affiliated Pacific islands.
In the western tropical Pacific, elevated rates of sea-level rise (up to 1 centimeter/year) affect coastal infrastructure, freshwater resources, and terrestrial and marine ecosystems on U.S.-affiliated islands like the Marshall Islands, American Samoa, and the Northern Marianas. Alterations in storm patterns, contamination of freshwater aquifers by saltwater flooding, and permanent inundation by rising sea level—all fueled by climate change—threaten long-term human habitation on many of these atolls. Efforts to relocate coastal inhabitants from some low-lying Pacific Islands are already underway.
Along Arctic shores of Alaska, shoreline erosion and habitat loss are accelerating due to increasing permafrost thaw and sea ice forming much later in the year, leaving the coast more susceptible to waves and storm surge. Alaskan government agencies and land-use planners are relocating some Native Alaskan villages and critical airstrips farther inland from eroding shores, such as Kivalina on the northwestern coast.
The U.S. west coast is vulnerable as well. In California alone, roughly half a million people and $100 billion worth of coastal property are at risk during the next century. In highly developed coastal areas such as San Francisco Bay and Puget Sound, hundreds of millions of dollars are being spent on restoration of nearshore ecosystems, which protect shorelines from erosion by waves and provide habitat for socially and economically important species. But resource managers remain uncertain whether outcomes of these efforts will be resilient to projected sea-level rise.
Because the impacts of climate change and sea-level rise around the Pacific and Arctic vary considerably, no single solution can mitigate the impacts. Coastal communities, along with federal, state, and local managers, need better scientific information and tools to plan for the particular threats they may face from saltwater flooding, shoreline erosion, and habitat loss.
Historically, simple “bathtub” models of future sea levels have assumed a static coast—one that is neither subsiding nor rising, neither retreating nor growing seaward—and they calculate future flooding based on just sea-level rise and tides, ignoring the impacts of storms. Those models cannot adequately account for the diverse influences that affect most coasts, including sediment input, how the coast is shaped, and “forcings”—atmospheric and oceanographic conditions that force the environment to change (for example, wind and circulation patterns, wave heights and directions).
Thus, in tectonically active coastlines like the U.S. west coast, USGS seeks to develop models that incorporate sea-level rise projections combined with storm impacts, as well as potential changes in wave heights and storm patterns associated with climate change.
What the USGS is doing
We are developing rigorous research tools to understand the physical impacts that climate change and sea-level rise will have on dynamic geologic settings along Pacific and Arctic coasts. This research covers an enormous range of coastal settings: from permafrost coasts, to the Puget Sound estuary, the California coast, and low-lying Pacific atolls.
By understanding the effects of extreme storms, including coastal flooding, changes in the shoreline, and movement of sediment, we can develop better models for understanding long-term vulnerability of sea-level rise in various coastal settings, and help coastal managers and businesses plan for a changing climate.
Our areas of study include the following, with brief descriptions of each.
Climate impacts to Arctic coasts
The Arctic region is warming faster than anywhere else in the nation. Understanding the rates and causes of coastal change in Alaska is needed to identify and mitigate hazards that might affect people and animals that call Alaska home.
Low-lying areas of tropical Pacific islands
Sea level is rising faster than projected in the western Pacific, so understanding how wave-driven coastal flooding will affect inhabited, low-lying islands—most notably, the familiar ring-shaped atolls—as well as the low-elevation areas of high islands in the Pacific Ocean, is critical for decision-makers in protecting infrastructure or relocating resources and people.
Dynamic coastlines along the western U.S.
The west coast of the United States is extremely complex and changeable because of tectonic activity, mountain building, and land subsidence. These active environments pose a major challenge for accurately assessing climate change impacts, since models were historically developed for more passive sandy coasts.
Estuaries and large river deltas in the Pacific Northwest
Essential habitat for wild salmon and other wildlife borders river deltas and estuaries in the Pacific Northwest. These estuaries also support industry, agriculture, and a large human population that’s expected to double by the year 2060, but each could suffer from more severe river floods, higher sea level, and storm surges caused by climate change.
Climate impacts on Monterey Bay area beaches
For a beach town like Santa Cruz, preserving beaches by mitigating coastal erosion is vital. USGS scientists conduct regular surveys of the beaches in the Monterey Bay region to better understand the short- and long-term impacts of climate change, El Niño years, and sea-level rise on a populated and vulnerable coastline.
Collaborators
Collaborators include USGS Coastal and Marine Geology Program colleagues in Woods Hole, Massachusetts, and St. Petersburg, Florida, and researchers with the USGS Western Ecological Research Center on Mare Island, California. Academic collaborators include those from University of Hawaiʻi, Oregon State University, University of Alaska, University of California, Scripps Institution of Oceanography, and University of Cantabria (Spain). Also involved are colleagues and federal partners from such agencies as the U.S. National Park Service, U.S. Fish and Wildlife Service, U.S. Department of Defense, and National Oceanic and Atmospheric Administration.
Below are all of the research topics associated with this project.
Dynamic coastlines along the western U.S.
Low-lying areas of tropical Pacific islands
Climate impacts to Arctic coasts
Using Video Imagery to Study Coastal Change: Santa Cruz Beaches
Climate impacts on Monterey Bay area beaches
Coastal Storm Modeling System (CoSMoS)
Using Video Imagery to Study Wave Dynamics: Unalakleet
Using Video Imagery to Study Coastal Change: Sunset State Beach
Using Video Imagery to Study Sediment Transport and Wave Dynamics: Nuvuk (Point Barrow)
Estuaries and large river deltas in the Pacific Northwest
Coastal Change Hazards
Below are data releases associated with this project.
Ocean wave time-series data simulated with a global-scale numerical wave model under the influence of historical and projected CMIP6 wind and sea ice fields (ver. 2.0, October 2024)
Model parameter input files to compare the influence of channels in fringing coral reefs on alongshore variations in wave-driven runup along the shoreline
Wave model results of the central Beaufort Sea coast, Alaska
Modeled extreme total water levels along the U.S. west coast
Model parameter input files to compare locations of coral reef restoration on different reef profiles to reduce coastal flooding
California shorelines and shoreline change data, 1998-2016
A GIS compilation of vector shorelines and coastal bluff edge positions, and associated rate-of-change data for Barter Island, Alaska
Modeled 21st century storm surge, waves, and coastal flood hazards and supporting oceanographic and geological field data (2010 and 2011) for Arey and Barter Islands, Alaska and vicinity
Projected responses of the coastal water table for California using present-day and future sea-level rise scenarios
Coral reef profiles for wave-runup prediction
Model parameter input files to compare wave-averaged versus wave-resolving XBeach coastal flooding models for coral reef-lined coasts
Physics-based numerical model simulations of wave propagation over and around theoretical atoll and island morphologies for sea-level rise scenarios
Below are multimedia items associated with this project.
The degradation of coastal habitats, particularly coral reefs, raises risks by increasing the exposure of coastal communities to flooding hazards during storms. The protective services of these natural defenses are not assessed in the same rigorous economic terms as artificial defenses, such as seawalls, and therefore often are not considered in decision-making.
The degradation of coastal habitats, particularly coral reefs, raises risks by increasing the exposure of coastal communities to flooding hazards during storms. The protective services of these natural defenses are not assessed in the same rigorous economic terms as artificial defenses, such as seawalls, and therefore often are not considered in decision-making.
Barter Island sits at the top of the Arctic National Wildlife Refuge in Alaska, and with the Arctic facing quickly rising temperatures, USGS wants to investigate what’s causing the North Slope bluffs to erode so quickly.
Barter Island sits at the top of the Arctic National Wildlife Refuge in Alaska, and with the Arctic facing quickly rising temperatures, USGS wants to investigate what’s causing the North Slope bluffs to erode so quickly.
This time-lapse of Barter Island in Alaska during three summer months in 2014, shows the pack ice melting and the subsequent effects to the beach and permafrost cliffs from storms and summer temperatures. This camera sat on a fallen snow fence to capture storm events.
This time-lapse of Barter Island in Alaska during three summer months in 2014, shows the pack ice melting and the subsequent effects to the beach and permafrost cliffs from storms and summer temperatures. This camera sat on a fallen snow fence to capture storm events.
Below are publications associated with this project.
A numerical study of geomorphic and oceanographic controls on wave-driven runup on fringing reefs with shore-normal channels
Characterizing storm-induced coastal change hazards along the United States West Coast
Global and regional sea level rise scenarios for the United States
Digital Twin Earth - Coasts: Developing a fast and physics-informed surrogate model for coastal floods via neural operators
Projecting climate dependent coastal flood risk with a hybrid statistical dynamical model
Assessment of barrier island morphological change in northern Alaska
Drivers of extreme water levels in a large, urban, high-energy coastal estuary – A case study of the San Francisco Bay
Multiple climate change-driven tipping points for coastal systems
Global-scale changes to extreme ocean wave events due to anthropogenic warming
Twenty-first-century projections of shoreline change along inlet-interrupted coastlines
The value of US coral reefs for flood risk reduction
The application of ensemble wave forcing to quantify uncertainty of shoreline change predictions
Below are data releases associated with this project.
Future Coastal Flooding
Prediction of Flooding Now and Into the Future: a geonarrative on coastal storms
Coastal Change in Alaska
Alaska's north coast has been home to indigenous communities for centuries. Changing coastlines threaten important infrastructure and historic sites that support indigenous communities. Changing coastlines also can potentially reduce habitat for Arctic wildlife, such as polar bears, shorebirds, and walruses. Oil- and gas-related development sites and U.S. Department of Defense installations
The Role of U.S. Coral Reefs in Coastal Protection
U.S. Geological Survey scientists have shown that along with providing food, tourism, and biodiversity, coral reefs also protect dollars and lives. This interactive geonarrative introduces the USGS research to understand the role of US coral reefs in coastal protection.
National Shoreline Change
Exploring Shoreline Positions of the United States From the 1800s To The Present. This geonarrative explains how the USGS derives shorelines from various data sources, and how shoreline change rates are generated from these data. The Natural Hazards Mission Area programs of the USGS develop and apply hazard science to help protect the safety, security, and economic well-being of the Nation.
Real-Time Forecasts of Coastal Change
U.S. Geological Survey researchers develop tools to forecast coastal change hazards. This geonarrative features research and tools developed to forecast real-time coastal change.
Our Coasts
USGS Coastal Change Hazards research provides scientific tools to protect lives, property, and the economic well being of the Nation. The mission of the USGS Coastal Change Hazards Program is to provide research and tools to protect lives, property, and the economic well-being of the Nation. This is a story map that introduces the value of our coasts and the threats they face with global change.
Below are news stories associated with this project.
Below are partners associated with this project.