Climate Impacts in Alaska
On This Page
- Over the past 50 years, Alaska has warmed twice as fast as the national average.
- Warming is contributing to the thawing of Alaska's permafrost. By the end of this century, the permafrost boundary is likely to shift northward hundreds of miles, increasing the risk for infrastructure damage.
- Warming is contributing to the loss of protective sea ice along Alaska's northwestern coast, leading to increased rates of coastal erosion.
- Warming is altering marine and terrestrial ecosystems, causing changes in the extent and location of habitat for fish and wildlife.
- Climate change places significant stress on the livelihoods, villages, and cultures al values of Alaska Natives.
- Climate Change and Water: Alaska
- USGCRP Global Climate Change Impacts in the United States: Alaska
- EPA Region 10 (including the Pacific Northwest states of AK, ID, OR, and WA)
- American Indian Environmental Office
Climate Impacts on Alaska
Alaska is a huge state with a wide range of climatic and ecological conditions. It is known for its rainforests, glaciers, boreal forest, tundra, peatlands, and meadows. Alaska contains 75% of U.S. national parks and 90% of U.S. wildlife refuges, by area.
Over the past 50 years, temperatures across Alaska increased by an average of 3.4°F. Winter warming was even greater, rising by an average of 6.3°F.The rate of warming in Alaska was twice the national average over that same period of time. Average annual temperatures in Alaska are projected to increase an additional 3.5 to 7°F by the middle of this century.
Precipitation in Alaska has also increased slightly, but the trend is not significant. Climate projections indicate that Alaskan winters are likely to be wetter, and that summers could become drier, as rising air temperatures accelerate the rate of evaporation.
Permafrost is the frozen ground located one to two feet below the surface in cold regions. As permafrost thaws and the soil sinks, structures built on or within the soil are damaged. Although most Alaskans live in permafrost-free areas, an estimated 100,000 Alaskans (about 14% of the population) live in areas sensitive to permafrost degradation.As explained below, the impacts of melting permafrost on transportation, forests, ecosystems, and the economy could have widespread implications for Alaskans.
Permafrost Impacts on Transportation
Permafrost thawing and cycles of freezing and thawing can cause extensive damage to highways, railroads, airstrips, and other transportation infrastructure in Alaska.
Many of Alaska's highways are built on permafrost. When permafrost thaws, roads buckle. Vehicles are only allowed to drive across certain roads in the tundra when the ground is frozen solid. In the past 30 years, the number of days when travel is allowed on the tundra has decreased from 200 days to 100 days per year.Projected increases in temperatures and permafrost thawing would continue this trend and could further limit access to the tundra. Building infrastructure on thawing permafrost requires additional engineering, and can increase the cost of construction by 10% or more.
For more information on climate change impacts on transportation, please visit the Transportation Impacts page.
Permafrost Impacts on Forests
As temperatures rise and permafrost thaws, the softening soil interferes with tree root systems. The altered soil conditions cause trees to sink into the ground. As a result, the trees in many of Alaska's forests lean, creating so-called "drunken forests."
For more information on climate change impacts on forests, please visit the Forest Impacts page.
Permafrost Impacts on Ecosystems
Over the past 50 years, thawing permafrost and increased evaporation have caused a substantial decline in the area of Alaska's closed-basin lakes (lakes without stream inputs and outputs). These surface waters and wetlands provide breeding habitat for millions of waterfowl and shorebirds that winter in the lower 48 states.These wetland ecosystems and the wildlife resources are important to Alaska Natives who hunt and fish for food.
Other Impacts on Ecosystems
As the climate warms, shrubs are invading the tundra. In some areas, the shrubs are replacing lichens and other tundra vegetation. Lichens are an important winter food source for caribou, and the loss of lichens can lead to declines in the growth and abundance of these animals. Caribou in turn are a critical food source for predators such as bears and wolves, as well as for Alaska Natives.
Higher temperatures and less summer moisture increase the risks of drought, wildfire, and insect infestation. Alaska's boreal spruce forest declined substantially in recent decades from both fire and insect damage. By mid-century, the average area burned by wildfire each year is likely to double.
For more information on climate change impacts on ecosystems, please visit the Ecosystems Impacts page. For more information on climate change impacts on forests, please visit the Forest Impacts page.
Impacts on Oceans and Coasts
The extent of sea ice is declining throughout the Arctic. Sea ice is frozen seawater floating on the surface of the ocean. Some sea ice persists from year to year (known as perennial sea ice), often getting thicker as it piles up against Arctic shorelines. Other sea ice melts during the warm season and refreezes in the cold season. Over the past several decades, the perennial sea ice has declined dramatically. This decline is, in part, a result of extended periods of above-freezing air or water temperatures. Ocean currents and winds have also played an important role, pushing perennial sea ice out of the Arctic basin. The average sea ice extent in September has decreased by 11.5% per decade over the past 30 years. Climate models project that sea ice will continue to retreat during the 21st century. Late summers could be nearly ice-free as early as about the 2040s.
Diminishing sea ice has opened new opportunities for shipping, oil and gas exploration, and other economic activities. However, it has also created a pathway for invasive species and caused the loss of critical habitat for a variety of ice-dependent species, including walruses and polar bears. Changes in sea ice can also affect the timing and location of plankton blooms, which can in turn affect the areas where commercial fisheries can thrive. Landfast ice (sea ice that has frozen along the shore) is important because it protects coastal shorelines and human settlements from flooding and erosion caused by storms, wind, and wave damage.
For more information on climate change impacts on coasts, please visit the Coastal Impacts page.
Impacts on Alaska Natives
People in Alaska are already feeling the impact of climate change. In many parts of the state, the changing climate has negatively affected the livelihood, settlements, and well-being of residents. Alaska Natives fish in ocean and inland waters. They also hunt animals such as polar bears, walruses, seals, and caribou for food. As climate change reduces these species' critical habitats, declines in their population threaten not only the livelihood of Alaska Natives, but also their cultural and social identity. As the supply of fish and game declines, hunters and fishers are forced to seek alternative sources of food.
Along Alaska's northwestern coast, increased coastal erosion is causing some shorelines to retreat at rates averaging tens of feet per year.Here, melting sea ice has reduced natural coastal protection. In Shishmaref, Kivalina, and other Alaska Native Villages, erosion has caused homes to collapse into the sea. Severe erosion has forced some Alaska Native Villages' populations to relocate in order to protect lives and property.
To learn more about what Alaska is doing to adapt to climate change impacts, please visit the adaptation section of the Alaska Impacts and Adaptation page.
 USGCRP (2000). Climate Change Impacts in the United States: The Potential Consequences of Climate Variability and Change. United States Global Change Research Program. Cambridge University Press, Cambridge, United Kingdom.
 USGCRP (2009). Global Climate Change Impacts in the United States. Karl, T. R., J. M. Melillo, and T. C. Peterson (eds.). United States Global Change Research Program. Cambridge University Press, New York, NY, USA.
 ACIA (2004). Impacts of a Warming Arctic: Arctic Climate Impact Assessment. Arctic Climate Impact Assessment. Cambridge University Press, Cambridge, United Kingdom.
 USARC (2003). Climate Change, Permafrost, and Impacts on Civil Infrastructure(PDF, 72 pp, 4.8MB) U.S. Arctic Research Commission, Arlington, VA, USA.
 NRC (2011). Climate Stabilization Targets: Emissions, Concentrations, and Impacts over Decades to Millennia. National Research Council. The National Academies Press, Washington, DC, USA.
 Anisimov, O.A., D.G. Vaughan, T.V. Callaghan, C. Furgal, H. Marchant, T.D. Prowse, H. Vilhjálmsson and J.E. Walsh (2007). Polar regions (Arctic and Antarctic). In: Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change Parry, M.L., O.F. Canziani, J.P. Palutikof, P.J. van der Linden and C.E. Hanson (eds.). Cambridge University Press, Cambridge, United Kingdom.
 Alaska Climate Impact Assessment Commission (2008). Final Commission Report. Alaska State Legislature.