Oil Development Impacts on the North Slope of Alaska
The exploration and development of oil on the North Slope of Alaska is one of the largest industrial undertakings in the Arctic. Since the discovery of oil at Prudhoe Bay in 1968, development has spread east, west, and offshore, sending several billion barrels of oil south through the Trans-Alaska Pipeline. The 19 producing oil fields on the North Slope are spread over more than 1,000 square miles of tundra and wetland. Roads, pipelines, drilling pads, airstrips, and other infrastructure in the central Arctic oilfields have covered more than 9,000 acres of tundra.
The National Research Council of the National Academies found that oil development on Alaska's North Slope has had significant effects on wildlife, including direct mortality, displacement, enhanced predator populations, and reduced reproductive rates of birds. The National Research Council also found that the impacts of oil development extend far beyond the immediate "footprint" of the oilfield infrastructure.
Impacts on caribou have been substantial. Oil development has displaced caribou from their core calving grounds and reduced productivity in the Central Arctic Herd. In the early 1990s the Alaska Department of Fish and Game found that caribou inhabiting the oilfield had lower calf productivity than animals from the same herd that calved farther away from oil-related facilities. Caribou use of preferred habitat in a given area declines exponentially as the density of roads increases, as is happening as development expands (Cameron et al. 1992, Nellemann and Cameron 1996, 1998).
Offshore, there is much concern about marine mammals, especially polar bears. Seismic surveys conducted in winter are supposed to avoid polar bear dens, but the location of most dens is unknown and they thus cannot be avoided until it is too late. If females abandon their dens, the cubs may die. Other marine mammals, such as endangered bowhead whales, may be affected by the noise associated with offshore exploration and development.
Pollution from oilfield activities is a major threat to the North Slope environment. Air pollution, wastewater, disposal of drilling muds, and frequent spills of oil and other chemicals combine to spread heavy metals, nitrogen oxides, and petroleum hydrocarbons over the development area and beyond. Emissions of nitrogen oxide from the oil fields on the North Slope are twice the total emissions of Washington, DC.
Impacts on the North Slope are expected to grow. Although future development likely includes more satellite fields on small gravel pads with disconnected road systems, the road network will grow, as will the gravel-covered footprint and extent of gravel mines. One major oil spill has already occurred on the North Slope (Atigun River, 1979), and the threat of a large marine spill is real. Such a spill could not be cleaned up, especially in broken ice conditions, and would jeopardize seals, polar bears, and molting waterfowl (in nearshore lagoons).
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