Climate impacts to Arctic coasts

Science Center Objects

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. 

Hole in the ground at the edge of the Arctic grassy bluff near a sandy beach with crafted wooden walls and ladder leading down

Native in-ground ice cellars can disappear as bluffs erode and permafrost thaws, such as this one in Wainwright, Alaska.

Flooded runway area with runway light poking through the water and a truck in the background is on non-flooded area.

This airport runway, the main lifeline for inhabitants on Barter Island, floods annually during storms. A new runway is being built farther inland on higher ground.



Animation depicting seasonal cycles on Alaska's Arctic bluffs. Click play to watch, or open in a new window for more information.

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.


Recorded June 1, 2019 - August 18, 2019

Video shows a series of photos taken every hour during daylight hours in the summer of 2019. The camera looks westward along the coastal bluffs of Barter Island, located on Alaska’s North Slope. A pole on the bluff, visible in the first half of the video, once supported another video camera that was aimed at the shoreline to study wave and shoreline dynamics. This video starts on June 1st at -4°C (25° F) when the bluffs are still frozen, snow is on the ground, and the winter pack ice protects the permafrost cliffs from wave attack. By the end of June, the ice and snow are gone, temperatures often climb to 12°C (54° F), and waves begin to lap at the narrow beach below the bluffs. In mid-July, the now-thawed, upper active layer of the tundra begins to slough off onto the beach. By the end of July, waves accompanied with elevated storm-tides erode the lower part of the slope. Just days later, as erosion increases rapidly, the bluff supporting the camera gives way and the camera tumbles onto the beach. Despite its fall onto the muddy beach, the camera continued to record and was successfully recovered in order to create this video. The USGS is studying this highly erosive stretch of Arctic coastline to try to better understand the main driving forces behind the erosion and why erosion rates seem to be increasing. The increase 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.


Video Transcript

Time-lapse photography: Summer thawing of frozen tundra allows bluff edges to slump in this photo of Barter Island on Alaska’s Arctic coast in July 2014. Also, pack ice recedes from the shore in summer, leaving bluff bases exposed to storm waves. View time-lapse photographs of this coast spanning three months in summer 2014.

Image: Permafrost Erosion Measurement

USGS researcher Benjamin Jones measures erosion along part of Alaska’s Arctic coast. At left is one example of a collapsed block of ice-rich permafrost near Drew Point.

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.

Man stands on arctic coastal bluff holding drill, another person in background walks the rocky beach.

A handheld auger is used to drill holes into the permafrost to place temperature sensors.(Credit: Christopher Arp, USGS. Public domain.)

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.

Figure shows a series of blue dots and red dots, which are the location of aerial photographic surveys along Alaskan north coast

Figure shows aerial photography surveys along Alaska's northern coast, from the U.S.–Canada border to Cape Sabine during 2006 and 2009. View the oblique imagery from 2006 and 2009.

Oblique aerial view of a coastline with eroding bluff, part of the bluff has been anchored with large, black sand-filled bags.

An oblique aerial photograph shows the currently active Long Range Radar Site on Barter Island, formerly a DEW Line (Distant Early Warning) station that was deactivated in 1990. The Cold War-era landfill in the foreground of the photograph was at immediate risk from coastal erosion in 2006 and has since been relocated farther inland. Photo from oblique imagery archive.

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 (see example) at the time of collection (2009–2012), and will help inform models of coastal inundation and hazards.

Man holds a piece of cylindrical steel attached to a handle and thick chain, on the stern of a moving boat.

USGS geologist Bruce Richmond prepares to deploy a pipe dredge that will be dragged along the seabed to collect sediment.

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.

Map with varying colors of dots, each color corresponding to the amount of shoreline change, either plus or minus.

Map above shows color-coded shoreline change rates, the boundaries of the ten analysis regions (dashed boxes and numbers), and key geographic locations discussed in the report "National Assessment of Shoreline Change: Historical Shoreline Change Along the North Coast of Alaska, U.S.-Canadian Border to Icy Cape," USGS Open-File Report 2015-1048)


Large sand bags are piled high, with protective fencing near a building, along the shorebreak as ocean waves lap.

Coastal villages throughout the Arctic region, such as Wainwright shown here, face significant erosion threats.

To learn more about climate change research in the Arctic, please read:

The Challenges of Arctic Fieldwork” — Sound Waves Newsletter article, December 2019

USGS provides information about Alaska coastal change to Scientific American” — USGS Pacific Coastal and Marine Science Center News, December 2017

Updated assessment of erosion rates on Alaska’s Arctic coast” — USGS Pacific Coastal and Marine Science Center News, November 2017

ABC News speaks to USGS researchers about Arctic coastal change” — USGS Pacific Coastal and Marine Science Center News, November 2017

“Northern Alaska Coastal Erosion Threatens Habitat and Infrastructure” — Sound Waves Newsletter article, September 2015

“Congressional Staffers Learn about Climate-Change Threats to Coastal Communities in California, Alaska, and Pacific Islands” — USGS Pacific Coastal and Marine Science Center News, September 2015

“New USGS report: Coastal erosion threatens northern Alaska” — Associated Press article and KTUU Television video, July 2015

“North Slope coastal erosion rates are among worst in nation, USGS reports” — Alaska Dispatch News story and video, July 2015

“Getting up close and personal with Alaska’s coastline” — Alaska Dispatch News, February 2015

“Alaska’s outdated maps make flying a peril, but a high-tech fix is slowly gaining ground” — Washington Post, October 2014

“Erosion Doubles Along Part of Alaska's Arctic Coast — Cultural and Historical Sites Lost” — USGS newsletter Sound Waves, May 2009

“The Shrinking Beaufort Sea Coastline: A USGS team is assessing changes along the North Slope coastline using historical and contemporary maps and aerial surveys” — Petroleum News article republished in USGS newsletter Sound Waves, May 2009

“Polar Disorder: The Edge of Extinction” — Vanity Fair News, April 2008 

“North to Alaska—an Aerial Shoreline Reconnaissance” — Sound Waves Newsletter article, October 2006

Alaska Mapped and the Statewide Digital Mapping Initiative: Imagery and elevation data with a statewide, broad-scale focus