The Arctic region is a delicate ecosystem. Temperatures are rising at approximately three to four times the global average. This rapid warming makes the Arctic particularly susceptible to climate change impacts. Extensive ice and permafrost contribute to its sensitivity, with changes having far-reaching implications beyond the Arctic Circle.
Iconic Arctic Mammals
Large Arctic mammals, dependent on sea ice, face consequences from a changing climate. Their survival strategies are linked to this habitat. As sea ice diminishes, these animals must adapt or face challenges.
Polar bears rely on sea ice as a platform for hunting seals, their primary food source. Melting sea ice reduces hunting time, forcing bears into longer fasting periods and increased energy expenditure. This impacts body condition, reproductive success, and cub survival, leading to substantial declines in some subpopulations.
Loss of sea ice forces polar bears to swim longer distances between floes, costly and risking cubs. Bears increasingly spend time on land, where high-fat seal prey is limited. Land-based food sources lack adequate nutrition, impacting fat reserves.
Ringed and bearded seals depend on sea ice. Ringed seals use stable ice and snow cover for lairs (snow caves) to give birth and nurse pups. Insufficient snow or premature melt exposes pups to predators and harsh weather, increasing mortality. Bearded seals require suitable sea ice over shallow waters for birthing, nursing, molting, and resting.
Walruses are impacted by diminishing sea ice, using floes as resting platforms. When ice is unavailable, thousands gather on land in crowded “haul-outs.” Aggregations lead to stress; easily spooked animals can trigger stampedes, injuring or killing young calves.
Forced land haul-outs mean walruses must travel longer distances (over 100 miles) to reach offshore feeding grounds. This expends energy, leading to exhaustion and malnutrition, especially for nursing females and their young. This impacts their access to abundant food sources.
Terrestrial and Freshwater Animals
Animals in Arctic land and freshwater systems face challenges from climate change, including altered vegetation, snow, and water chemistry. These shifts impact their food, reproduction, and predator evasion.
Reindeer and caribou are sensitive to changes in winter snow. Increased “rain-on-snow” events create impenetrable ice crusts over their winter forage (lichens), making food difficult to access, potentially leading to starvation. Shrubification, the expansion of woody shrubs into tundra, alters foraging grounds, as these plants are less nutritious.
Altered vegetation and snow patterns affect caribou migration routes and increase insect harassment during warmer summers. Some herds, like the Bathurst, have experienced severe population declines. These changes disrupt traditional movements and foraging efficiency.
Arctic foxes and their prey (lemmings and voles) are influenced by snow depth and quality. Lemmings rely on stable, deep snow for insulation and protection. Reduced snow cover or altered properties expose lemmings, making them vulnerable. Conversely, increased snow depth can hinder fox hunting.
The stability of lemming populations affects Arctic fox breeding success. A warming Arctic allows red foxes to expand northward, increasing competition and displacing Arctic foxes. This shift in predator dynamics adds complexity.
Freshwater fish (e.g., Arctic char) are vulnerable to rising water temperatures and changes in water chemistry. Arctic char are cold-water specialists; warmer temperatures reduce suitable habitat and impact spawning. Permafrost thaw releases dissolved organic carbon and metals into freshwater systems, altering water quality, affecting fish health.
Marine Life and Arctic Birds
The warming Arctic Ocean impacts marine life and birds in these waters. Changes in sea ice, ocean temperature, and chemistry create challenges for these animals.
Arctic whales (e.g., bowhead, narwhals) are experiencing disruptions. Reduced sea ice opens new shipping lanes, increasing vessel noise pollution. This noise interferes with communication, navigation, and food location. Some whales are altering migration, delaying movements, and increasing exposure to shipping traffic.
Ocean warming shifts whale prey distribution, forcing them to travel further or seek less nutritious food. For narwhals, changing sea ice timing can delay southward migration, increasing entrapment risks in freezing ice. Increased human activity in newly accessible areas poses risks of ship strikes and entanglements.
Arctic fish species (e.g., Arctic cod) are vulnerable to ocean warming and acidification. Cod embryos and larvae are sensitive to temperature increases, slight warming leading to higher mortality or deformed larvae. Ocean acidification threatens these populations and fisheries.
Changes in ocean temperature and sea ice affect zooplankton distribution and abundance. Large, energy-rich copepods are dwindling, replaced by smaller, less nutritious zooplankton. This shift cascades through the food web, impacting health and populations of higher species, including seabirds.
Seabirds (e.g., ivory gulls, common eiders) face foraging and nesting challenges. Ivory gulls, dependent on sea ice for hunting/scavenging, have declined. Reduced sea ice forces them to travel farther for food, impacting breeding success. Altered ice conditions affect eiders by changing prey access and exposing nesting colonies to predation.
Cascading Ecosystem Effects
Arctic changes affect ecosystems. These impacts highlight the fragility of polar environments.
Food web disruptions are a consequence of climate change. Declining sea ice impacts ice algae, the marine food web’s base, affecting zooplankton. Reduced energy-rich zooplankton cascades to Arctic cod, other fish, marine mammals, and seabirds. Changes in terrestrial vegetation, like lichen loss due to ice crusts, impact herbivores (e.g., caribou), with ripple effects on predators.
These cumulative impacts contribute to biodiversity loss. Cold-adapted species face increasing challenges, struggling to find suitable habitats or food as warmer-adapted species expand northward. This “Arctic squeeze” can lead to the displacement or decline of native Arctic species, reducing regional life variety.
Ecosystem functions are altered. Thawing permafrost releases organic carbon and nutrients into waterways and the atmosphere, changing water chemistry, potentially accelerating global warming. This shift influences nutrient cycling in terrestrial and freshwater systems. The timing of primary productivity in marine environments is affected by altered ice conditions, impacting ecosystem energy flow.
Widespread changes reduce Arctic ecosystem resilience, making them less able to withstand future disturbances. The rapid transformation rate makes adaptation difficult for species and ecological processes, leading to a less stable, predictable environment.