August 2014 saw the Barents and Kara seas return to temperatures that are closer to the historical average after anomalously warm summer temperatures last year: in 2013, the southern Barents Sea was as much as 11 degrees Celsius (20 degrees F) above than average!
Summer sea surface temperatures in the Arctic Ocean are largely determined by patterns of sea-ice retreat in the surrounding area and the amount of solar radiation absorbed by the ocean’s surface layer. As sea ice retreats in summer and previously ice-covered water is exposed to the sun’s radiation, sea surface and upper ocean temperatures increase.
The most significant example of this long-term trend is in the Chukchi Sea, northwest of Alaska, where sea surface temperatures have increased at a rate of 0.5 degrees Celsius per decade (0.9 degrees F). The Bering Strait region, which saw the largest temperature anomaly in the Arctic this year, includes the Chukchi Sea.
Warming ocean temperatures affects a host of Arctic conditions, from evaporation and cloudiness to the location and abundance of marine life. Warming oceans are prompting the migration and expansion of species typically found at lower latitudes. Biologists have documented new species in multiple areas of the Arctic Ocean. Although some of these new species reports likely reflect increased surveying efforts, rising temperatures are also playing a role in the Arctic's changing biological diversity.
Continued warming has the potential to introduce new and potentially disruptive species, some of which might compete with or prey upon the Arctic's existing marine life.
More details on Arctic ocean temperatures can be found in the Vital Signs chapter of the 2014 Arctic Report Card.