This website is the digital version of the 2014 National Climate Assessment, produced in collaboration with the U.S. Global Change Research Program.
For the official version, please refer to the PDF in the downloads section. The downloadable PDF is the official version of the 2014 National Climate Assessment.
Credits | Site MapThe National Climate Assessment summarizes the impacts of climate change on the United States, now and in the future.
A team of more than 300 experts guided by a 60-member Federal Advisory Committee produced the report, which was extensively reviewed by the public and experts, including federal agencies and a panel of the National Academy of Sciences.
Explore the effects of climate change
Alaska has warmed twice as fast as the rest of the nation, bringing widespread impacts. Sea ice is rapidly receding and glaciers are shrinking. Thawing permafrost is leading to more wildfire, and affecting infrastructure and wildlife habitat. Rising ocean temperatures and acidification will alter valuable marine fisheries.
Explore how climate change is affecting Alaska.
The Alaska region includes the state of Alaska and its surrounding waters. The Highlights section below offers a high-level overview of climate change impacts on this region, including the five Key Messages and selected topics. (see Ch. 22: Alaska)
Arctic summer sea ice is receding faster than previously projected and is expected to virtually disappear before mid-century. This is altering marine ecosystems and leading to greater ship access, offshore development opportunity, and increased community vulnerability to coastal erosion.
Most glaciers in Alaska and British Columbia are shrinking substantially. This trend is expected to continue and has implications for hydropower production, ocean circulation patterns, fisheries, and global sea level rise.
Permafrost temperatures in Alaska are rising, a thawing trend that is expected to continue, causing multiple vulnerabilities through drier landscapes, more wildfire, altered wildlife habitat, increased cost of maintaining infrastructure, and the release of heat-trapping gases that increase climate warming.
Current and projected increases in Alaska’s ocean temperatures and changes in ocean chemistry are expected to alter the distribution and productivity of Alaska’s marine fisheries, which lead the U.S. in commercial value.
The cumulative effects of climate change in Alaska strongly affect Native communities, which are highly vulnerable to these rapid changes but have a deep cultural history of adapting to change.
Over the past 60 years, Alaska has warmed more than twice as rapidly as the rest of the U.S., with average annual air temperature increasing by 3°F and average winter temperature by 6°F, with substantial year-to-year and regional variability.3 Most of the warming occurred around 1976 during a shift in a long-lived climate pattern (the Pacific Decadal Oscillation) from a cooler pattern to a warmer one. The underlying long-term warming trend has moderated the effects of the more recent shift of the Pacific Decadal Oscillation to its cooler phase in the early 2000s.4,5 Alaska’s warming involves more extremely hot days and fewer extremely cold days.3,6 Because of its cold-adapted features and rapid warming, climate change impacts on Alaska are already pronounced, including earlier spring snowmelt, reduced sea ice, widespread glacier retreat, warmer permafrost, drier landscapes, and more extensive insect outbreaks and wildfire.
Inupiaq seal hunter on the Chukchi Sea. Reductions in sea ice alter food availability for many species from polar bear to walrus, and make hunting less safe for Alaska Native hunters.
The state’s largest industries, energy production, mining, and fishing, are all affected by climate change. Continuing pressure for oil, gas, and mineral development on land and offshore in ice-covered waters increases the demand for infrastructure, placing additional stresses on ecosystems. Land-based energy exploration will be affected by a shorter season when ice roads are viable, yet reduced sea ice extent may create more opportunity for offshore development.
Alaska is home to 40% of the federally recognized tribes in the United States.7 The small number of jobs, high cost of living, and rapid social change make rural, predominantly Native, communities highly vulnerable to climate change through impacts on traditional hunting and fishing and cultural connection to the land and sea.
As temperatures rise, permafrost thawing increases. Maps show projections of average annual ground temperature at a depth of 3.3 feet for three time periods if emissions of heat-trapping gases continue to grow (higher scenario, A2), and if they are substantially reduced (lower scenario, B1). (Figure source: Permafrost Lab, Geophysical Institute, University of Alaska Fairbanks).
Local governments and tribes throughout Alaska are planting native vegetation, moving inland or away from rivers, and building riprap walls, seawalls, or groins, which are shore-protection structures built perpendicular to the shoreline.1 Left photo shows a Homer seawall battered by waves while still under construction.
Villages including Newtok, Shishmaref (right photo), and Kivalina are facing relocation because of sea level rise and coastal erosion. Storm surges that used to be buffered by ice are now causing more shoreline and infrastructure damage. Residents of these villages face thawing permafrost, tilting houses, and sinking boardwalks along with aging fuel tanks and other infrastructure. Newtok has worked for a generation to move to a safer location, but current federal legislation does not authorize federal or state agencies to assist communities in relocating, or the use of public funds to repair or upgrade storm-damaged infrastructure in flood-prone locations.2 Shishmaref and Kivalina are also seeking to relocate but have been similarly unsuccessful.
Arctic sea ice extent and thickness have declined substantially, especially in late summer (September), when there is now only about half as much sea ice as at the beginning of the satellite record in 1979.8,9 The seven Septembers with the lowest ice extent all occurred in the past seven years. Sea ice has also become thinner, with less ice lasting over multiple years, and is therefore more vulnerable to further melting.9 Models that best match historical trends project that northern waters will be virtually ice-free in late summer by the 2030s.10,11,12
Reductions in sea ice increase the amount of the sun’s energy absorbed by the ocean. This melts more ice, leaving more dark open water that gains even more heat, leading to a self-reinforcing cycle that increases warming.
In Alaska, 80% of land is underlain by permafrost – frozen ground that restricts water drainage and therefore strongly influences landscape water balance and the design and maintenance of infrastructure. More than 70% of this area is vulnerable to subsidence (land sinking) upon thawing because of its ice content.13 Permafrost near the Alaskan Arctic coast has warmed 6°F to 8°F at 3.3 foot depth since the mid-1980s.14 Thawing is already occurring in interior and southern Alaska, where permafrost temperatures are near the thaw point.15,16 Permafrost will continue to thaw,17,18,19 and some models project that near-surface permafrost will be lost entirely from large parts of Alaska by the end of this century.20
, 2011: Reduction in areal extent of high-latitude wetlands in response to permafrost thaw. Nature Geoscience, 4, 444-448, doi:10.1038/ngeo1160. | Detail ↩
, 2012: Alaska Region Overview. U.S. Department of the Interior, Bureau of Indian Affairs. URL | Detail ↩
, 2014: Using climate divisions to analyze variations and trends in Alaska temperature and precipitation. Journal of Climate, in press, doi:10.1175/JCLI-D-13-00342.1. URL | Detail ↩
, 2011: Climate-induced community relocations: Creating an adaptive governance framework based in human rights doctrine. New York University Review Law & Social Change, 35, 357-408. URL | Detail ↩
, 2008: Weather and Climate Extremes in a Changing Climate - Regions of Focus - North America, Hawaii, Caribbean, and U.S. Pacific Islands. A Report by the U.S. Climate Change Science Program and the Subcommittee on Global Change Research. Vol. 3.3Department of Commerce, NOAA's National Climatic Data Center, 164 pp. URL | Detail ↩
, 2006: Importance of recent shifts in soil thermal dynamics on growing season length, productivity, and carbon sequestration in terrestrial high-latitude ecosystems. Global Change Biology, 12, 731-750, doi:10.1111/j.1365-2486.2006.01113.x. URL | Detail ↩
, 2011: Geomorphic change in northern Canada. Changing Cold Environments: A Canadian Perspective, , John Wiley & Sons, Ltd, 200-221. | Detail ↩
, 2013: Homer, Alaska’s Climate Adaptation Progress Despite Uncertainties. ICLEI. URL | Detail ↩
, 2012: Numerical modeling of permafrost dynamics in Alaska using a high spatial resolution dataset. The Cryosphere Discussions, 6, 89-124, doi:10.5194/tcd-6-89-2012. | Detail ↩
, 2008: Permafrost characteristics of Alaska. Extended Abstracts of the Ninth International Conference on Permafrost, June 29-July 3, 2008., , University of Alaska Fairbanks, 121-123. URL | Detail ↩
, 2008: Incorporating organic soil into a global climate model. Climate Dynamics, 30, 145-160, doi:10.1007/s00382-007-0278-1. URL | Detail ↩
, 2012: The future of Arctic sea ice. Annual Review of Earth and Planetary Sciences, 40, 625-654, doi:10.1146/annurev-earth-042711-105345. URL | Detail ↩
, 2010: Permafrost thermal state in the polar Northern Hemisphere during the international polar year 2007-2009: A synthesis. Permafrost and Periglacial Processes, 21, 106-116, doi:10.1002/ppp.689. URL | Detail ↩
, 2008: Soil climate and frost heave along the Permafrost/Ecological North American Arctic Transect. Proceedings of the Ninth International Conference on Permafrost, 2, 1519-1524. | Detail ↩
, 2013: Regional Climate Trends and Scenarios for the U.S. National Climate Assessment: Part 7. Climate of Alaska. NOAA Technical Report NESDIS 142-7. 60 pp. URL | Detail ↩
, 2007: Arctic sea ice decline: Faster than forecast. Geophysical Research Letters, 34, L09501, doi:10.1029/2007GL029703. URL | Detail ↩
, 2012: The Arctic’s rapidly shrinking sea ice cover: A research synthesis. Climatic Change, 110, 1005-1027, doi:10.1007/s10584-011-0101-1. URL | Detail ↩
, 2009: A sea ice free summer Arctic within 30 years? Geophysical Research Letters, 36, L07502, doi:10.1029/2009GL037820. URL | Detail ↩
, 2012: A sea ice free summer Arctic within 30 years: An update from CMIP5 models. Geophysical Research Letters, 39, L18501, doi:10.1029/2012GL052868. URL | Detail ↩
, 2012: The first decade of the new century: A cooling trend for most of Alaska. The Open Atmospheric Science Journal, 6, 111-116, doi:10.2174/1874282301206010111. URL | Detail ↩
The National Climate Assessment summarizes the impacts of climate change on the United States, now and in the future.
A team of more than 300 experts guided by a 60-member Federal Advisory Committee produced the report, which was extensively reviewed by the public and experts, including federal agencies and a panel of the National Academy of Sciences.
2014 National Climate Assessment. U.S. Global Change Research Program
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