Bering Sea and Climate Change

As one of the major large marine ecosystems in the world and home to large bird and marine mammal populations, the climate and ecosystem of the Bering Sea has changed over the last 50 years.

It is interesting and important to consider how the weather of the Bering Sea has varied over the last few decades. Originally a cold, Arctic ecosystem dominated by sea ice earlier in the 20th century, the Bering Sea climate changed to a sub-Arctic climate after 1976. Warming temperatures have continued—in recent winters, temperatures are above freezing … records tell us that sea ice has retreated sooner than normal, which means that spring has been happening a week or two earlier than “normal.”

These warming temperatures mean some creatures are thriving and others are not. Pollock—one of the world’s largest food fish resources—populations have increased by an enormous 400%. Greenland turbot—a valuable commercial fish—which favors cold, near-bottom waters, has dropped in population by over 80%. Another bottom-dweller, the snow crab, has likewise reduced in population in the last five years due, in part, to warmer water temperatures.

Marine mammals may also be affected by climate. There was a major decrease in fur seal pups born after the late 1970s, and again in the late 1990s. Alternately, fin and humpback whale populations seem to have increased in the late 1990s compared to earlier decades.

Warming temperatures also reduce the quality of Arctic sea ice, making hunting more difficult for the Arctic’s native people. Even the whales have moved further north to cooler waters.

Warmer ocean temperatures and a lack of sea ice in the southern Bering Sea mean since the late 1990s mean that the ocean can absorb more solar energy. This makes it even more resistant to the formation of new sea ice next winter.

The winter of 2002-2003 was one of the warmest on record in the eastern Bering Sea and western Alaska. Will these warming changes go on? It is impossible to predict future climate, but evidence suggests that these current, warmer conditions will continue.

Sources courtesy of: http://www.beringclimate.noaa.gov/bering_status_overview.html, http://www.beringclimate.noaa.gov/essays_bond.html

Image courtesy of: http://nmml.afsc.noaa.gov/gallery/cetaceans/mn-83_humpback.htm