Over the past 50 years, Alaska has warmed faster than the rest of the United States. The higher temperatures in Alaska are already causing earlier spring snowmelt, reduced sea ice, widespread glacier retreat, insect outbreaks, and permafrost warming. For example, the frost-free season in Fairbanks has gone from 80 to 120 days since 1904, while the Tanana River break-up at Nenana has advanced by about one week since 1920.Since the 1950s, Kotzebue’s mean annual temperature has increased about 3°F. The warming in winter has been even more notable with Kotzebue’s average winter temperature increasing by more than 6°F. While this might not sound dramatic, it is more than enough to significantly alter the finely-tuned natural landscape.
Every year Arctic sea ice expands and contracts with the seasons: in winter it grows to the size of the United States and in summer half of it disappears. On a large scale, shrinking sea ice is one of the more worrisome and more visible impacts of a warming climate. Why is Arctic sea ice so important? Sea ice has a bright surface, reflecting back 80% of the sunlight that strikes it. As sea ice melts, dark ocean water is exposed, which absorbs 90% of the sunlight instead of reflecting it. The ocean heats up, and Arctic temperatures rise further which leads to even more ice melt. Shrinking sea ice also alters the timing and location of plankton blooms and critically threatens ice-dwelling animals such as walrus, polar bears, and certain seals. Some marine species are shifting northward.If the northern ice pack continues to decrease in coverage and thickness, researchers suggest the possibility of a seasonally ice-free Arctic—an area that has been covered by ice for at least three million years—and a vastly changed world.
On the Selawik Refuge and elsewhere, warming permafrost threatens many aspects of the human and natural environment. Permafrost (ground that stays frozen year-round) on the refuge is only 1-2°F below freezing, which means it does not take much climate warming for the permafrost to begin to thaw. Temperatures at the Selawik refuge are projected to rise as much as 10°F by 2080, bringing the average annual temperature from below the freezing point (about 22°F) to just above the freezing point (about 32°F), spelling the end of permafrost. Lakes are already shrinking or disappearing as a result of a longer warm season and thawing permafrost in their beds. Saltwater from nearby brackish estuaries could intrude into freshwater system in low-lying refuge areas if the underground “ice dams” that currently separate the two thaw and degrade. Millions of waterfowl and shorebirds and a wide variety of fish and aquatic life that depend on the waters and wetlands of the refuge are vulnerable to these changes.
In 2004 a large chunk of earth collapsed along the upper Selawik River as a result of permafrost failure, spewing mud and silt into the water and pushing the river against its far bank. Gooey sediment from the collapse turned the clear upper Selawik River into an opaque, turbid stream. Several years later this “thaw slump,” the largest of its kind in Alaska, continues to erode, depositing fine silt into the river. Important spawning grounds for sheefish and whitefish are located downstream of the slump. Several studies supported by the refuge are underway to examine the effects of the slump on sheefish survival, deposition of sediment, water quality, river erosion, and slump progression. An unusual geologic feature, the slump has attracted the attention of university researchers and others interested in investigating its causes and effects.Watch our video about the Selawik River thaw slump.
Observations by Alaska Native elders confirm many of the same changes documented by scientists, particularly in patterns of wind, temperature, ice, and currents in northern Alaska, which have reduced hunters’ access to marine mammals. Fall storms have become more destructive to the coastline, accelerating erosion. Precipitation patterns have changed with little snow in fall and early winter. Bird migrations are early, unfamiliar insects appear in summer, and willows are growing taller and denser. The Iñupiat of Kotzebue have observed increased variability and unpredictability in weather since the 1970s. In roadless northwest Alaska, environmental conditions critically influence hunters’ ability to travel and access migratory animal resources. Unfamiliar new patterns of wind, weather, ice, snow, and other factors impede local residents’ ability to move about safely and to harvest, process, and store wild foods effectively.
The environmental changes brought about by a warming climate will alter the ecosystems and resources with which we are familiar. Caribou, fish, birds, marine mammals, vegetation, and cultural resources are likely to be changed in significant ways not completely foreseeable at this time. Although not all environmental change will be negative, the potential magnitude and scope of these changes will profoundly affect human communities in Alaska, including subsistence activities, transportation, health, community infrastructure, and economic pursuits. Alaska Native communities are among the most critically situated in the nation today to prepare for and respond to climate change.
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"Siilvik" is the Inupiaq name for Selawik, meaning "place of sheefish." One of two sheefish spawning areas in the region is in the upper Selawik River.