Climate Change on U.S. Arctic Ocean Margins
Arctic Alaska is warming faster than the rest of the United States. A major consequence of this warming is permafrost thaw, which threatens infrastructure, alters habitat, increases fire risk, changes nutrient and sediment delivery to the coastal ocean, and enhances greenhouse gas release. The warming climate has already dramatically reduced the thickness and annual duration of sea ice, rendering the Arctic U.S. Exclusive Economic Zone more accessible to other nations’ vessels and the coastlines more vulnerable to erosion from wave action. Coastal bluffs, which serve as polar bear nurseries and as protection for some Native settlements, and low relief barrier islands and coastal plains, which are the site of most energy production infrastructure, are susceptible to the impacts of increased storm intensity and sea level rise, additional consequences of a warming climate. Identifying and quantifying these effects are made particularly challenging by the Arctic’s remote location and harsh climate.
CMHRP scientists lead regional-scale studies that measure and model the impact of climate change across the land-ocean interface at the edge of the Arctic Ocean in northern Alaska. Using laser-based methods and photography, several USGS projects, including Climate Impacts to Arctic Coasts, Coastal National Elevation Database (CoNED), and CMHRP’s National Assessment of Shoreline Change, have mapped coastal landforms at high resolution and documented landscape changes due to permafrost degradation and coastal erosion taking place over months to decades.
To more accurately evaluate the impact of accepted global warming scenarios on the Alaskan Arctic coastline over the next century, CMHRP ocean-atmosphere models take into account field measurements of sea level, salinity, water and sediment temperature, and sediment characteristics near areas currently being inundated by rising seas. The models predict periods of increased flooding in low-lying areas in the coming decades and highlight the vulnerability of barrier islands to storm surges.
CMHRP scientists have also tracked methane dynamics in thermokarst lakes on the Alaskan North Slope and reconstructed climate changes over the past 20,000 years since the end of the last major glaciation. Offshore, CMHRP researchers have measured emissions of methane and carbon dioxide, two important greenhouse gases, imaged nearly ubiquitous shallow gas in seafloor sediments there, and mapped the distribution of gas hydrates. The CMHRP has also mapped the seaward extent of subsea permafrost along the entire Arctic Ocean coastline of northern Alaska. The subsea permafrost persists only to about 20 km offshore, implying rapid thawing of permafrost under the inundated shelf since the end of the last major glaciation.
Explore the CMHRP Decadal Strategic Plan geonarrative, and learn more about the USGS project on climate impacts to Arctic coasts
The CMHRP Decadal Science Strategy 2020-2030
Climate impacts to Arctic coasts
Arctic Alaska is warming faster than the rest of the United States. A major consequence of this warming is permafrost thaw, which threatens infrastructure, alters habitat, increases fire risk, changes nutrient and sediment delivery to the coastal ocean, and enhances greenhouse gas release. The warming climate has already dramatically reduced the thickness and annual duration of sea ice, rendering the Arctic U.S. Exclusive Economic Zone more accessible to other nations’ vessels and the coastlines more vulnerable to erosion from wave action. Coastal bluffs, which serve as polar bear nurseries and as protection for some Native settlements, and low relief barrier islands and coastal plains, which are the site of most energy production infrastructure, are susceptible to the impacts of increased storm intensity and sea level rise, additional consequences of a warming climate. Identifying and quantifying these effects are made particularly challenging by the Arctic’s remote location and harsh climate.
CMHRP scientists lead regional-scale studies that measure and model the impact of climate change across the land-ocean interface at the edge of the Arctic Ocean in northern Alaska. Using laser-based methods and photography, several USGS projects, including Climate Impacts to Arctic Coasts, Coastal National Elevation Database (CoNED), and CMHRP’s National Assessment of Shoreline Change, have mapped coastal landforms at high resolution and documented landscape changes due to permafrost degradation and coastal erosion taking place over months to decades.
To more accurately evaluate the impact of accepted global warming scenarios on the Alaskan Arctic coastline over the next century, CMHRP ocean-atmosphere models take into account field measurements of sea level, salinity, water and sediment temperature, and sediment characteristics near areas currently being inundated by rising seas. The models predict periods of increased flooding in low-lying areas in the coming decades and highlight the vulnerability of barrier islands to storm surges.
CMHRP scientists have also tracked methane dynamics in thermokarst lakes on the Alaskan North Slope and reconstructed climate changes over the past 20,000 years since the end of the last major glaciation. Offshore, CMHRP researchers have measured emissions of methane and carbon dioxide, two important greenhouse gases, imaged nearly ubiquitous shallow gas in seafloor sediments there, and mapped the distribution of gas hydrates. The CMHRP has also mapped the seaward extent of subsea permafrost along the entire Arctic Ocean coastline of northern Alaska. The subsea permafrost persists only to about 20 km offshore, implying rapid thawing of permafrost under the inundated shelf since the end of the last major glaciation.
Explore the CMHRP Decadal Strategic Plan geonarrative, and learn more about the USGS project on climate impacts to Arctic coasts