Climate impacts to Arctic coasts Active
Coastal Change in Alaska
Why USGS scientists are studying Alaska's coasts, and what we've learned
Physical features of a changing Arctic
Collapsing bluffs, salt-killed tundra, and drained thermokarst lakes on Pingok Island
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.
During research trips near the tiny village of Wainwright on Alaska’s North Slope, USGS scientist Li Erikson has encountered native in-ground cellars along the bluff’s edge. Alaska natives have called this rugged region of frozen tundra home for generations, yet modern conveniences such as sewage lines and grocery stores are not found in many areas this far north. So for years the indigenous people have used their naturally cold surroundings to their advantage—instead of modern refrigeration, they dig holes in the permafrost about 10 feet deep and 5 feet long to preserve the food that sustains them. However, as the permafrost thaws and coastal erosion increases, some of these natural iceboxes are beginning to disappear.
Issue
Alaska’s North Slope is home to the Iñupiat people, their archeological sites, and food resources that have sustained them for millennia. This area is a major migratory path for several bird species and other important Department of Interior trust species, such as polar bears. Prudhoe Bay is at the center of oil and gas production in Alaska and the site of numerous exploration wells and pipelines, which are at risk from spills, leaks, and inundation. Sandbags and shore protection structures have been emplaced to protect land and infrastructure in many of the villages and oil and gas production facilities. For example, on Barter Island, the airport runway is being relocated to higher ground to escape increased flooding and erosion by storm waves.
Although Alaska’s north coast experiences both erosion and accretion, it is predominantly erosional, retreating on average about 1.4 meters per year; very high rates of erosion—up to 20 meters per year—occur along some sections of coast, such as Drew Point, Alaska. The numerous low-lying barrier islands—which provide habitat for nesting birds, buffer wave energy reaching the mainland coast, and regulate salt and freshwater exchange in the lagoons—are extremely mobile and experience high rates of both erosion and accretion.
Ocean pack ice borders the coast from October to July and normally protects the barrier islands and mainland coast against winter storm flooding and erosion. The ice now forms later than in previous years, thus lengthening the ice-free period. Delayed formation of sea ice raises the potential for damage to the coast from storms arriving later in the season. It’s still uncertain whether these late storms are increasing in intensity.
In addition, the tundra typically has an upper active layer, which is the zone above the permafrost that thaws in summer and refreezes in winter. The active layer appears to be thickening in some regions each year; exactly where and why this is happening is unknown, but it may be linked to why the bluffs are failing. The release of large amounts of carbon and methane associated with permafrost degradation is also of concern.
Human adaptation to these changes is also difficult. Though major infrastructure in villages can be moved, relocation comes at great cost and with some concern that new sites might also be at risk from future erosion. Gathering baseline data on Alaska’s changing shoreline and the forces that are driving change can help scientists develop models of a future shoreline. This research can help government officials protect villages, mitigate threats to oil and gas infrastructure, and manage habitat for endangered and threatened species.
What the USGS is doing
The USGS team aims to determine the dominant forces causing beach and bluff erosion. To do this, they are modeling sea-level rise combined with projected storm activity to create maps of likely inundation—the first 21st-century flood maps of the area. They are examining the physical characteristics of the bluffs, the beach, and the nearby seafloor. Physical measurements collected in the field are vital to feed into models to understand how this wild landscape is evolving.
To quantify bluff erosion, scientists map the bluff edges using portable GPS units. After collecting samples of sediment on the beach and seafloor, the scientists measure its composition and grain size to help them model how waves and currents transport sediment. To monitor permafrost temperatures, scientists drill holes into the permafrost to place temperature sensors, or thermistor arrays. They also measure the thickness of the active layer. Resistivity instruments placed in the ground can be used to calculate how much of the ground is resistant to electrical conductivity. As ice does not conduct electricity, these measurements will indicate the presence of ice and fluctuations of the permafrost thickness. Knowing how the depth of the active layer varies throughout the summer warming period can help the team determine if this dynamic makes bluffs more susceptible to failure. In addition, collecting soil samples helps USGS microbiologists assess the role of microbes in the changing tundra.
To gain an initial understanding of the landscape where they would be working, the team flew the coast in 2006 and 2009 to collect 7,800 digital photographs and about 20 hours of continuous video along an 800-kilometer stretch of coast from Cape Sabine, Alaska, to the U.S.–Canada border. This effort was part of the USGS National Assessment of Shoreline Change project, designed to document and evaluate beach erosion along U.S. open-ocean shorelines. In Alaska, historical data on shoreline positions and coastal elevation are limited. Whereas records date back 150 years for most of the United States, Alaska’s historical shoreline maps, where they exist, go back only to the 1940s. It is extremely challenging to assess shoreline changes based on a paucity of data, in a region undergoing complex changes to ice cover, land subsidence, and shoreline position.
Using digitized historical maps from the 1940s and aerial and satellite imagery from the 2000s, the team calculated shoreline-change rates every 50 meters, which divided the coastline into nearly 27,000 sections. Airborne lidar surveys were collected between Icy Cape and the U.S.–Canada border (a stretch of coast about the length of California) over the course of four years in cooperation with the Arctic Landscape Conservation Cooperative and the Bureau of Land Management. The team incorporated these elevation data into a data set that can be used to define the shoreline position at the time of collection (2009–2012), and will help inform models of coastal inundation and hazards.
These data and present-day elevation and shoreline maps are a starting point for monitoring future changes to Alaska’s landscape. Additionally, several time-lapse cameras around the island capture terrain and coastal changes. Watch multiple-month time-lapse videos of Barter Island’s north coast, with examples of slumping bluffs:
Getting people and gear to this remote region with limited amenities requires creative planning, and often requires help from partner agencies already established there, such as the U.S. Fish and Wildlife Service which has a permanent facility in Kaktovik. The team also engaged the community (the city of Kaktovik, the Kaktovik Iñupiat Corporation, and local residents) through outreach on USGS research activities.
Though vital and exciting frontier work, Arctic research does have its challenges—whether it’s walking on unstable bluffs in the fog, discovering fresh bear tracks following researchers’ footprints, or returning to a building to find a fire has destroyed much of the scientific gear. Transit into and out of Barter Island is often delayed due to inclement weather closing the small airstrip.
What the USGS has learned
Alaska’s north coast is predominantly erosional, averaging a loss of 1.4 meters a year. Along a much smaller stretch (60 kilometers) of this coastline (approximately box 6 in map below), USGS found that average annual erosion rates doubled from historical levels of about 20 feet per year between the mid-1950s and late-1970s, to 45 feet per year between 2002 and 2007. The study along that stretch of the Beaufort Sea also verified the disappearance of cultural and historical sites, including Esook, a hundred-year-old trading post now underwater on the Beaufort Sea floor, and Kolovik (Qalluvik), an abandoned Iñupiaq village site that may soon be lost.
The change in erosion rates is likely the result of several changing Arctic conditions, including declining sea-ice extent, increasing summertime sea-surface temperature, rising sea level, and possible increases in storm power and corresponding wave action. More long-term work is needed to understand the interplay of these factors and how they drive changes in coastal erosion.
This research is part of the USGS project titled, “Coastal Climate Impacts.”
Explore other research topics associated with this project, below.
Coastal Climate Impacts
Below are data releases associated with this project.
Below are multimedia items associated with this project.
Below are publications associated with this project.
Seasonal electrical resistivity surveys of a coastal bluff, Barter Island, North Slope Alaska
Hindcast storm events in the Bering Sea for the St. Lawrence Island and Unalakleet Regions, Alaska
USGS Arctic Science Strategy
National assessment of shoreline change: a GIS compilation of vector shorelines and associated shoreline change data for the north coast of Alaska, U.S.-Canadian border to Icy Cape
National assessment of shoreline change: historical change along the north coast of Alaska, U.S.-Canadian border to Icy Cape
Progress report for project modeling Arctic barrier island-lagoon system response to projected Arctic warming
Regional shoreline change and coastal erosion hazards in Arctic Alaska
Wave climate and trends along the eastern Chukchi Arctic Alaska coast
Oblique Aerial Photography of the Arctic Coast of Alaska, Cape Sabine to Milne Point, July 16-19, 2009
Oblique Aerial Photography of the Arctic Coast of Alaska, Nulavik to Demarcation Point, August 7-10, 2006
Increase in the rate and uniformity of coastline erosion in Arctic Alaska
Modern erosion rates and loss of coastal features and sites, Beaufort Sea coastline, Alaska
Below are data releases associated with this project.
Below are news stories associated with this project.
- Overview
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.
During research trips near the tiny village of Wainwright on Alaska’s North Slope, USGS scientist Li Erikson has encountered native in-ground cellars along the bluff’s edge. Alaska natives have called this rugged region of frozen tundra home for generations, yet modern conveniences such as sewage lines and grocery stores are not found in many areas this far north. So for years the indigenous people have used their naturally cold surroundings to their advantage—instead of modern refrigeration, they dig holes in the permafrost about 10 feet deep and 5 feet long to preserve the food that sustains them. However, as the permafrost thaws and coastal erosion increases, some of these natural iceboxes are beginning to disappear.
Issue
Alaska’s North Slope is home to the Iñupiat people, their archeological sites, and food resources that have sustained them for millennia. This area is a major migratory path for several bird species and other important Department of Interior trust species, such as polar bears. Prudhoe Bay is at the center of oil and gas production in Alaska and the site of numerous exploration wells and pipelines, which are at risk from spills, leaks, and inundation. Sandbags and shore protection structures have been emplaced to protect land and infrastructure in many of the villages and oil and gas production facilities. For example, on Barter Island, the airport runway is being relocated to higher ground to escape increased flooding and erosion by storm waves.
Although Alaska’s north coast experiences both erosion and accretion, it is predominantly erosional, retreating on average about 1.4 meters per year; very high rates of erosion—up to 20 meters per year—occur along some sections of coast, such as Drew Point, Alaska. The numerous low-lying barrier islands—which provide habitat for nesting birds, buffer wave energy reaching the mainland coast, and regulate salt and freshwater exchange in the lagoons—are extremely mobile and experience high rates of both erosion and accretion.
Ocean pack ice borders the coast from October to July and normally protects the barrier islands and mainland coast against winter storm flooding and erosion. The ice now forms later than in previous years, thus lengthening the ice-free period. Delayed formation of sea ice raises the potential for damage to the coast from storms arriving later in the season. It’s still uncertain whether these late storms are increasing in intensity.
In addition, the tundra typically has an upper active layer, which is the zone above the permafrost that thaws in summer and refreezes in winter. The active layer appears to be thickening in some regions each year; exactly where and why this is happening is unknown, but it may be linked to why the bluffs are failing. The release of large amounts of carbon and methane associated with permafrost degradation is also of concern.
Human adaptation to these changes is also difficult. Though major infrastructure in villages can be moved, relocation comes at great cost and with some concern that new sites might also be at risk from future erosion. Gathering baseline data on Alaska’s changing shoreline and the forces that are driving change can help scientists develop models of a future shoreline. This research can help government officials protect villages, mitigate threats to oil and gas infrastructure, and manage habitat for endangered and threatened species.
What the USGS is doing
The USGS team aims to determine the dominant forces causing beach and bluff erosion. To do this, they are modeling sea-level rise combined with projected storm activity to create maps of likely inundation—the first 21st-century flood maps of the area. They are examining the physical characteristics of the bluffs, the beach, and the nearby seafloor. Physical measurements collected in the field are vital to feed into models to understand how this wild landscape is evolving.
To quantify bluff erosion, scientists map the bluff edges using portable GPS units. After collecting samples of sediment on the beach and seafloor, the scientists measure its composition and grain size to help them model how waves and currents transport sediment. To monitor permafrost temperatures, scientists drill holes into the permafrost to place temperature sensors, or thermistor arrays. They also measure the thickness of the active layer. Resistivity instruments placed in the ground can be used to calculate how much of the ground is resistant to electrical conductivity. As ice does not conduct electricity, these measurements will indicate the presence of ice and fluctuations of the permafrost thickness. Knowing how the depth of the active layer varies throughout the summer warming period can help the team determine if this dynamic makes bluffs more susceptible to failure. In addition, collecting soil samples helps USGS microbiologists assess the role of microbes in the changing tundra.
To gain an initial understanding of the landscape where they would be working, the team flew the coast in 2006 and 2009 to collect 7,800 digital photographs and about 20 hours of continuous video along an 800-kilometer stretch of coast from Cape Sabine, Alaska, to the U.S.–Canada border. This effort was part of the USGS National Assessment of Shoreline Change project, designed to document and evaluate beach erosion along U.S. open-ocean shorelines. In Alaska, historical data on shoreline positions and coastal elevation are limited. Whereas records date back 150 years for most of the United States, Alaska’s historical shoreline maps, where they exist, go back only to the 1940s. It is extremely challenging to assess shoreline changes based on a paucity of data, in a region undergoing complex changes to ice cover, land subsidence, and shoreline position.
Using digitized historical maps from the 1940s and aerial and satellite imagery from the 2000s, the team calculated shoreline-change rates every 50 meters, which divided the coastline into nearly 27,000 sections. Airborne lidar surveys were collected between Icy Cape and the U.S.–Canada border (a stretch of coast about the length of California) over the course of four years in cooperation with the Arctic Landscape Conservation Cooperative and the Bureau of Land Management. The team incorporated these elevation data into a data set that can be used to define the shoreline position at the time of collection (2009–2012), and will help inform models of coastal inundation and hazards.
These data and present-day elevation and shoreline maps are a starting point for monitoring future changes to Alaska’s landscape. Additionally, several time-lapse cameras around the island capture terrain and coastal changes. Watch multiple-month time-lapse videos of Barter Island’s north coast, with examples of slumping bluffs:
Getting people and gear to this remote region with limited amenities requires creative planning, and often requires help from partner agencies already established there, such as the U.S. Fish and Wildlife Service which has a permanent facility in Kaktovik. The team also engaged the community (the city of Kaktovik, the Kaktovik Iñupiat Corporation, and local residents) through outreach on USGS research activities.
Though vital and exciting frontier work, Arctic research does have its challenges—whether it’s walking on unstable bluffs in the fog, discovering fresh bear tracks following researchers’ footprints, or returning to a building to find a fire has destroyed much of the scientific gear. Transit into and out of Barter Island is often delayed due to inclement weather closing the small airstrip.
What the USGS has learned
Alaska’s north coast is predominantly erosional, averaging a loss of 1.4 meters a year. Along a much smaller stretch (60 kilometers) of this coastline (approximately box 6 in map below), USGS found that average annual erosion rates doubled from historical levels of about 20 feet per year between the mid-1950s and late-1970s, to 45 feet per year between 2002 and 2007. The study along that stretch of the Beaufort Sea also verified the disappearance of cultural and historical sites, including Esook, a hundred-year-old trading post now underwater on the Beaufort Sea floor, and Kolovik (Qalluvik), an abandoned Iñupiaq village site that may soon be lost.
The change in erosion rates is likely the result of several changing Arctic conditions, including declining sea-ice extent, increasing summertime sea-surface temperature, rising sea level, and possible increases in storm power and corresponding wave action. More long-term work is needed to understand the interplay of these factors and how they drive changes in coastal erosion.
- Science
This research is part of the USGS project titled, “Coastal Climate Impacts.”
Explore other research topics associated with this project, below.Coastal Climate Impacts
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... - Data
Below are data releases associated with this project.
- Multimedia
Below are multimedia items associated with this project.
- Publications
Below are publications associated with this project.
Filter Total Items: 24Seasonal electrical resistivity surveys of a coastal bluff, Barter Island, North Slope Alaska
Select coastal regions of the North Slope of Alaska are experiencing high erosion rates that can be attributed in part to recent warming trends and associated increased storm intensity and frequency. The upper sediment column of the coastal North Slope of Alaska can be described as continuous permafrost underlying a thin (typically less than 1–2 m) active layer that responds variably to seasonal tAuthorsPeter W. Swarzenski, Cordell Johnson, Thomas Lorenson, Christopher H. Conaway, Ann E. Gibbs, Li H. Erikson, Bruce M. Richmond, Mark P. WaldropHindcast storm events in the Bering Sea for the St. Lawrence Island and Unalakleet Regions, Alaska
This study provides viable estimates of historical storm-induced water levels in the coastal communities of Gambell and Savoonga situated on St. Lawrence Island in the Bering Sea, as well as Unalakleet located at the head of Norton Sound on the western coast of Alaska. Gambell, Savoonga, and Unalakleet are small Native Villages that are regularly impacted by coastal storms but where little quantitAuthorsLi H. Erikson, Robert T. McCall, Arnold van Rooijen, Benjamin NorrisUSGS Arctic Science Strategy
The United States is one of eight Arctic nations responsible for the stewardship of a polar region undergoing dramatic environmental, social, and economic changes. Although warming and cooling cycles have occurred over millennia in the Arctic region, the current warming trend is unlike anything recorded previously and is affecting the region faster than any other place on Earth, bringing dramaticAuthorsMark Shasby, Durelle SmithNational assessment of shoreline change: a GIS compilation of vector shorelines and associated shoreline change data for the north coast of Alaska, U.S.-Canadian border to Icy Cape
The Arctic Coastal Plain of northern Alaska is an area of strategic economic importance to the United States, is home to remote Native communities, and encompasses unique habitats of global significance. Coastal erosion along the Arctic coast is chronic, widespread, and may be accelerating, which threatens defense- and energy-related infrastructure, natural shoreline habitats, and Native communitiAuthorsAnn E. Gibbs, Karen A. Ohman, Bruce M. RichmondNational assessment of shoreline change: historical change along the north coast of Alaska, U.S.-Canadian border to Icy Cape
Beach erosion is a persistent problem along most open-ocean shores of the United States. Along the Arctic coast of Alaska, coastal erosion is widespread, may be accelerating, and is threatening defense and energy-related infrastructure, coastal habitats, and Native communities. As coastal populations continue to expand and infrastructure and habitat are increasingly threatened by erosion, there isAuthorsAnn E. Gibbs, Bruce M. RichmondProgress report for project modeling Arctic barrier island-lagoon system response to projected Arctic warming
Changes in Arctic coastal ecosystems in response to global warming may be some of the most severe on the planet. A better understanding and analysis of the rates at which these changes are expected to occur over the coming decades is crucial in order to delineate high-priority areas that are likely to be affected by climate changes. In this study we investigate the likelihood of changes to habitatAuthorsLi H. Erikson, Ann E. Gibbs, Bruce M. Richmond, Curt D. Storlazzi, Benjamin M. JonesRegional shoreline change and coastal erosion hazards in Arctic Alaska
Historical shoreline positions along the mainland Beaufort Sea coast of Alaska were digitized and analyzed to determine the long-term rate of change. Average shoreline change rates and ranges from 1947 to the mid-2000s were determined every 50 meters between Barrow and Demarcation Point, at the U.S.-Canadian border. Results show that shoreline change rates are highly variable along the coast, withAuthorsAnn E. Gibbs, E. Lynne Harden, Bruce M. Richmond, Li H. EriksonWave climate and trends along the eastern Chukchi Arctic Alaska coast
Due in large part to the difficulty of obtaining measurements in the Arctic, little is known about the wave climate along the coast of Arctic Alaska. In this study, numerical model simulations encompassing 40 years of wave hind-casts were used to assess mean and extreme wave conditions. Results indicate that the wave climate was strongly modulated by large-scale atmospheric circulation patterns anAuthorsL. H. Erikson, C. D. Storlazzi, R. E. JensenOblique Aerial Photography of the Arctic Coast of Alaska, Cape Sabine to Milne Point, July 16-19, 2009
The Arctic Coastal Plain of northern Alaska, an area of strategic economic importance to the United States, is home to remote Native American communities and encompasses unique habitats of global significance. Coastal erosion along the Arctic coast is chronic and widespread; recent evidence suggests that erosion rates are among the highest in the world (as high as ~16 m/yr) and may be acceleratingAuthorsAnn E. Gibbs, Bruce M. RichmondOblique Aerial Photography of the Arctic Coast of Alaska, Nulavik to Demarcation Point, August 7-10, 2006
The Arctic Coastal Plain of northern Alaska, an area of strategic economic importance to the United States, is home to remote Native American communities and encompasses unique habitats of global significance. Coastal erosion along the Arctic coast is chronic and widespread; recent evidence suggests that erosion rates are among the highest in the world (up to ~16 m/yr) and may be accelerating. CoaAuthorsAnn E. Gibbs, Bruce M. RichmondIncrease in the rate and uniformity of coastline erosion in Arctic Alaska
Analysis of a 60 km segment of the Alaskan Beaufort Sea coast using a time‐series of aerial photography revealed that mean annual erosion rates increased from 6.8 m a−1(1955 to 1979), to 8.7 m a−1 (1979 to 2002), to 13.6 m a−1 (2002 to 2007). We also observed that spatial patterns of erosion have become more uniform across shoreline types with different degrees of ice‐richness. Further, during theAuthorsBenjamin M. Jones, C.D. Arp, M.T. Jorgenson, Kenneth M. Hinkel, Joel A. Schmutz, Paul L. FlintModern erosion rates and loss of coastal features and sites, Beaufort Sea coastline, Alaska
This study presents modern erosion rate measurements based upon vertical aerial photography captured in 1955, 1979, and 2002 for a 100 km segment of the Beaufort Sea coastline. Annual erosion rates from 1955 to 2002 averaged 5.6 m a-1. However, mean erosion rates increased from 5.0 m a-1 in 1955-79 to 6.2 m a-1 in 1979-2002. Furthermore, from the first period to the second, erosion rates increasedAuthorsBenjamin M. Jones, Kenneth M. Hinkel, C.D. Arp, Wendy R. Eisner - Web Tools
Below are data releases associated with this project.
- News
Below are news stories associated with this project.
Filter Total Items: 14