Alaska is a region experiencing rapid and visible climate change. Its high-latitude location places it at the forefront of global warming, offering insights into broader climatic shifts and the interconnectedness of Earth’s systems.
Accelerated Warming and Physical Changes
Alaska is experiencing warming at a rate significantly faster than the global average, a phenomenon known as Arctic amplification. While the global average temperature has increased by about 1.7 degrees Fahrenheit since 1970, Alaska has seen temperatures rise by approximately 4.2 degrees Fahrenheit during the same period, making it the fastest-warming U.S. state. This amplified warming is largely due to the “ice-albedo feedback,” where melting snow and ice reduce the reflective surface of the Earth, leading to greater absorption of solar radiation by darker land and ocean, which in turn causes further warming and melting.
The accelerated warming has significant physical consequences, particularly for permafrost. Permafrost, ground frozen for at least two consecutive years, underlies about 80% of Alaska’s land. As temperatures rise, this frozen ground thaws, leading to unstable terrain known as thermokarst. This process creates irregular surfaces with marshy hollows and hummocks, and can cause ground subsidence and collapse. Thawing permafrost also releases ancient organic carbon, which decomposes and emits greenhouse gases like methane and carbon dioxide, intensifying warming.
Another significant physical change is the retreat of Arctic sea ice. Sea ice acts as a climate regulator by reflecting sunlight and plays a protective role for coastlines. Since accurate satellite monitoring began in 1979, the September minimum sea ice coverage has fallen by about 50%, and sea-ice thickness has decreased by approximately three-quarters. Projections suggest the Arctic Ocean could be largely ice-free in summer as early as 2040.
Alaska’s glaciers are also melting at an accelerated pace, contributing to global sea-level rise. Between 2000 and 2023, Alaska’s glaciers contributed significantly to the global loss of approximately 6.542 trillion tonnes of ice, which raised global sea levels by 18 mm. Alaska alone accounted for nearly 25% of the total glacier mass loss worldwide during this period, with some glaciers thinning at twice the speed observed in the 1950s.
Impacts on Wildlife and Ecosystems
The physical changes across Alaska significantly impact its diverse wildlife and ecosystems. The retreat of sea ice directly impacts marine life that depends on it for survival. Polar bears, for example, rely on sea ice as a platform for hunting seals, their primary food source. As the ice recedes, bears are forced to travel longer distances or come ashore, potentially reducing their access to prey and affecting their body condition.
Walruses also depend on sea ice for resting between dives to forage for bottom-dwelling invertebrates like clams. With less floating summer sea ice, large groups of walruses are forced to haul out on crowded shorelines. These mass aggregations increase the risk of deadly stampedes if the animals are spooked. Ocean warming and acidification further threaten marine ecosystems; for example, increased ocean acidity can impair the ability of pteropods to develop properly. Pteropods are a food source for juvenile pink salmon, and their decline could affect salmon populations and body weight.
Terrestrial animals are also experiencing shifts due to warming temperatures and altered environments. Caribou migration patterns are changing, with some herds experiencing declines and altered movements. Milder winters and the expansion of woody shrubs into previously tundra-dominated areas have led to a substantial increase in moose populations in parts of Alaska.
The ecosystem itself is transforming, with the “greening” of the tundra becoming more pronounced through the expansion of deciduous shrubs. Simultaneously, warmer, drier conditions contribute to an increase in the frequency and intensity of wildfires across the state. From 2000 to 2020, 2.5 times more acres burned in Alaska than in the previous two decades, with a notable increase in tundra and boreal forest fires. These fires can release stored carbon, alter vegetation composition, and impact the recovery of slow-growing plants like lichens, a winter food source for caribou.
Consequences for Alaskan Communities
The environmental changes in Alaska directly affect the human population, particularly Indigenous communities whose cultural heritage and food security are deeply intertwined with the land and its resources. Coastal erosion, exacerbated by thawing permafrost and reduced sea ice, poses a significant threat to many villages. Without protective sea ice, coastlines are exposed to more intense storm surges and wave action, leading to rapid erosion. This erosion has forced difficult decisions about community relocation, a process that is costly and complex.
Thawing permafrost also damages infrastructure across the state. Roads, buildings, pipelines, and airports are all vulnerable to ground instability caused by melting subsurface ice. This damage leads to costly repairs and disruptions to transportation and energy systems, impacting daily life and economic activity.
Traditional subsistence lifestyles, which are central to the food security and cultural identity of many Alaska Native peoples, are under threat from these environmental shifts. Changing animal migration patterns make hunting more unpredictable and require hunters to travel farther. Unpredictable and thinning ice conditions make travel across frozen rivers and seas more dangerous for hunting and fishing.
Shifts in species availability, including declines in some salmon populations and snow crab due to warming waters and harmful algal blooms, directly impact traditional food sources. The inability to access or harvest traditional foods can lead to increased reliance on expensive store-bought food and a loss of cultural practices. Thawing permafrost can also affect traditional food storage methods, such as ice cellars, making them less effective at preserving food and potentially raising health concerns.
Economic Shifts and Challenges
Alaska’s broader economy is also grappling with the effects of climate change, leading to shifts and challenges in established industries. Commercial fishing, a significant contributor to the state’s economy, faces substantial impacts. Warming ocean temperatures have caused declines in commercially valuable species such as Pacific cod, Chinook salmon, and snow crab, leading to fishery closures and significant economic losses for fishing communities and thousands of jobs. Changes in ocean conditions can also shift fish populations northward or into deeper waters, altering traditional fishing grounds and increasing operational costs for fishermen.
Winter tourism, another established industry, is experiencing challenges due to unreliable snow and ice conditions. Shorter winter seasons and less predictable snow cover negatively affect snow sports businesses and increase costs for ski areas. While some areas might see extended sightseeing seasons due to warming, the overall quality and reliability of winter-dependent tourism activities are diminishing.
The melting of Arctic sea ice also presents potential new economic opportunities, such as the opening of new shipping routes like the Northwest Passage. These routes could offer shorter transit times between the Pacific and Atlantic oceans, potentially reducing fuel consumption for international shipping. However, these routes come with logistical and environmental risks, including the continued presence of ice, challenging weather conditions, and the lack of robust marine infrastructure for emergency response. The economic viability of these routes is still debated, as factors like insurance costs, fees, and the need for specialized vessels can offset potential savings.