Arctic Sea Ice
The Arctic’s icy beauty sustains charismatic species from the much-loved polar bear to the mythical narwhal. Here, sea ice floats on the ocean’s surface. It changes size seasonally, keeps the Arctic cool and moderates global climate. It is the platform where many species give birth, raise young, hunt, hide from predators and move long distances. Sea ice sustains a remote web of life: it supports marine algae at the base of the food web, and its spring melt drives phytoplankton blooms that enrich the marine ecosystem. The Bering Sea’s sea-ice bloom sustains a rich benthic community, providing food for walruses, bearded seals, and seaducks. It is one of the world’s most endangered habitats due to climate change. Climate scientists have projected that summer sea ice will disappear in the 2030s. Winter sea ice will also continue to decline.
A Home for Threatened and Endangered Species
Sea-ice provides critical habitat for imperiled species. The polar bear relies on sea ice to hunt, seek mates, move long distances and build dens to rear cubs. Polar bears
hunt seals at ice openings and by breaking into seal snow caves. Other imperiled species that depend on sea ice for rearing young, resting, and/or molting include the ringed, bearded, spotted, ribbon, harp, and hooded seals, Pacific walrus, and spectacled eider.
Climate Change Threats
The Arctic has warmed at twice the rate of the rest of the planet, causing sea ice to rapidly decline. In 2007, summer sea ice plummeted to a record low: ~1 million square miles below the 1979-2000 average—a level that most climate models projected would not be reached until 2050. The ice is also half as thin as it was a few decades ago, and it is melting earlier in spring and forming later in autumn. As sea ice hunting grounds shrink and break up early, polar bears in some regions are starving, drowning and resorting to cannibalism. If current emission trends continue, scientists predict two-thirds of the world’s polar bears will be lost by 2050. As temperatures rise, the ringed seals’ snow dens are collapsing and killing their
pups. The loss of sea ice over the Pacific walrus’ foraging grounds is forcing walruses to come ashore to rest—where vulnerable calves are trampled to death in stampedes. The spectacled eider faces shrinking sea ice over its winter feeding-grounds, which reduces its prey and eliminates its resting areas. The bowhead, beluga, and gray whale are threatened by the expansion of oil drilling and shipping traffic as sea ice melts.
Needed Conservation Measures
Reducing greenhouse gas is the most important step to slow and reverse the sea ice melt. To avoid the most severe impacts to the planet, the Intergovernmental Panel on Climate Change (IPCC) states a need to reduce emissions from 1990 levels 25 to 40 percent by 2020. Other recommendations go further and state that we should stabilize global CO2 levels to 350 ppm, below our present level of 389. To restore Arctic sea ice, the well-known leading climate scientists including James Hansen estimate that we’ll need to lower CO2 levels to 300-325 ppm. We must also increase habitat and species resilience by ending Arctic oil and gas development, prohibiting increased shipping as melting ice opens new routes, stopping overhunting and trade in imperiled wildlife, and reducing toxic contaminants. The United States must proactively protect the Arctic through multi-agency collaboration, domestic environmental law enforcement, and international mechanisms including the International Agreement for the Conservation of Polar Bears, the Arctic Council, the United Nations Convention on the Law of the Sea, and the United Nations Framework Convention on Climate Change.