An Alaska polar bear keeps close to her young along the Beaufort Sea coast in Arctic National Wildlife Refuge. Melting sea ice has made the polar bear a symbol of climate change impact. Photo: Susanne Miller, USFWS. Download.
With an area of more than 375 million acres extending 2,000 miles from east to west and 1,100 miles from north to south, Alaska dwarfs other states. The northernmost state is also unmatched in its range of climates and habitats — and nearly all are feeling impacts from climate change.
During the last half-century, Alaska has seen some of the most rapid warming on earth, with temperatures rising 1 to almost 4 degrees Fahrenheit across its climate regions and ecosystems. By the year 2100, the average annual temperature of Alaska’s North Slope is projected to rise another 10 degrees Fahrenheit.
“One big difference between Alaska and the Lower 48 is that here we’re dealing with impacts that have already occurred, not just forecasts of change,” says John Morton, Supervisory Fish and Wildlife Biologist at Alaska’s Kenai National Wildlife Refuge. “And because Alaska hasn’t undergone widespread landscape change from non-climate stressors such as agriculture and development, the impacts of climate change aren’t masked as they are elsewhere.”
|Change in mean annual temperatures in Alaska. Provided by the Alaska Climate Research Center. See full size.|
Climate change effects documented in the Arctic include rapidly eroding shorelines, melting permafrost (the normally frozen subsurface of two-thirds of the state), loss of Arctic sea ice and increased shrub growth at high latitudes. On the Kenai Peninsula alone, researchers have documented rising tree line, drying wetlands, glacial breakup, shrub encroachment into peat lands, and a change in wildfire patterns — all as a result of climate change.
A bull moose grazes at Kenai National Wildlife Refuge in Alaska. Moose, caribou and other Alaska land mammals will likely be affected by habitat shifts tied to climate change. Photo: Mike Boylan, USFWS. Download.
In recent decades, climate changes have also begun to impact Alaska’s wildlife, shrinking Arctic habitat for polar bears, changing waterfowl nesting times in the western deltas, and prompting historic forest pest outbreaks on the Kenai Peninsula. These impacts present a host of challenges to the U.S. Fish and Wildlife Service, which manages 16 national wildlife refuges in Alaska (covering more than 76 million acres or about one-fifth of the state). The impacts are also challenging iconic Alaska creatures such as caribou, walrus and others, including threatened, endangered and candidate species.
The polar bear —a symbol of climate change in Alaska — was listed as threatened under the Endangered Species Act in 2008 largely because of its dependence on Arctic sea ice, which has shrunken dramatically over the last three decades. In this video, Service polar bear biologist Eric Regehr captures and examines a polar bear. Among the things he looks for: evidence that climate change has affected the bear’s size and health, as it has done elsewhere in the bear’s range.
“Research such as Eric’s is helping us answer questions about polar bear in Alaska and elsewhere.” says Rosa Meehan, head of the Alaska Region’s Marine Mammals Management Program. “Insights from these studies provide a critical basis for collaborations with our partners in the Native community, state and industry, to reduce threats to polar bears today. Our hope is to maintain viable populations that will be able to reoccupy restored habitats should the threat of climate change diminish.”
In Alaska’s Yukon-Kuskokwim Delta, an emperor goose nesting island is exposed by pond drying tied to climate change. Photo: USFWS. Download.
The Arctic also provides breeding grounds for more than 100 species of birds, including species that breed nowhere else on the continent. Among these are species listed under the Endangered Species Act, such as Steller’s eiders and spectacled eiders, and candidate species such as yellow-billed loon and Kittlitz’s murrelets.
More than half a million geese and one million ducks, including the threatened spectacled eider, breed on the Yukon Kuskokwim Delta each year. As spring weather has warmed, hatch dates have moved up for geese and eiders; the eggs of cackling geese now hatch nine days earlier than they did when monitoring began in 1982. Whether earlier hatching will decrease future reproductive success is unknown; researchers are monitoring the situation. Researchers are also unsure if other climate change impacts — including erosion, flooding, salinization, melting permafrost, and sea level rise — could degrade nesting habitat and brood-rearing ponds. The Service is monitoring pond salinity to establish a baseline and gather trend data for future analyses.
The Kenai Peninsula recently saw one of the continent’s worst spruce bark beetle infestations, affecting more than a million acres of forest. A study of tree rings by biologists at Kenai Refuge, documenting 250 years of beetle activity, showed that outbreaks were caused not by forest disturbances such as logging but by climate patterns. Eleven years of warm summers from 1987 to 1997 prompted beetle populations to explode, killing virtually all mature white, Lutz and Sitka spruce trees on the western Kenai. Climate change models suggest that, after 2020, average summer temperatures on the Kenai will likely exceed thresholds that help control beetle populations. Land managers will have to adjust their practices to the new ecosystems that emerge after so many trees die.
Early and recent total extent of spruce bark beetle infestation on the Kenai Peninsula (Alaska Department of Natural Resources, Division of Support Services, Land Records Information Section, October 1998)
Some communities are already reacting, replanting beetle-killed areas with white spruce and lodgepole pine, and trying to reduce fire hazards along boundaries of natural lands. Says the Service’s Morton, “We’ve begun to think about the ecological consequences of facilitating adaptation, such as reforesting with lodgepole pine, a species that doesn’t naturally occur on the refuge.”
The needs of people must also be considered in addressing climate change. That’s especially true here, where Alaska Natives live in an intimate relationship with the land and share traditional knowledge handed down from their ancestors over centuries. Many residents of Alaska’s rural communities still depend on subsistence harvest for a large part of the food they eat. Climate change is already making subsistence hunting less dependable in some areas as habitats change and game species move. The northward expansion of beavers, for example, has blocked many traditional salmon-spawning streams, complains Inupiaq Elder Christina Westlake in this audio interview.
At Yukon Flats National Wildlife Refuge, salmon strips dry in a smokehouse in preparation for winter. Subsistence harvests on which many Native Alaskans and rural communities depend are being threatened by climate change. Photo: USFWS.
In facing these and other climate-related challenges, Alaska has one great advantage over other states: Ecosystems and landscapes here are still relatively intact. Maintaining habitat connectivity and migration routes for fish and wildlife will be a priority.
Though the scope of climate challenges in Alaska is daunting, Service commitment to habitat conservation is unwavering, says Alaska Regional Director Geoff Haskett. The Service, he says, will continue to monitor impacts, anticipate changes and respond as best it can to protect wildlife habitat. “Despite all the challenges,” he says, “the Service is dedicated to climate change research in Alaska, knowing that what we learn here will help our state and our nation better prepare for and counter the impacts of an uncertain future.”
Climate Change Focus: Adaptation
Author: Charla Sterne, FWS public affairs, Alaska Region
- USGS time lapse of shoreline erosion
- NSIDC animation of sea ice extent 1979 – present
- SNAP fact sheet: Climate change and Yukon Flats Refuge
- Audio of interview with Alaska Native Elder Christina Westlake
- Report: Connecting Landscape to the Future report