Warmer air and sea, declining ice continue to trigger Arctic change

What happens in the Arctic affects other parts of the world.

http://www.eurekalert.org/pub_releases/2015-12/nh-waa121415.php

Public Release: 15-Dec-2015
Warmer air and sea, declining ice continue to trigger Arctic change
Fish and walruses moving in face of new challenges
NOAA Headquarters

A new NOAA-sponsored report shows that air temperature in 2015 across the Arctic was well above average with temperature anomalies over land more than 2 degrees Fahrenheit above average, the highest since records began in 1900. Increasing air and sea surface temperatures, decreasing sea ice extent and Greenland ice sheet mass, and changing behavior of fish and walrus are among key observations released today in the Arctic Report Card 2015.

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Major findings of this year's report include:

Air temperature: The average annual air temperature over land areas between October 2014 and September 2015 was 2.3 degrees Fahrenheit (1.3 degrees Celsius) above average, the highest in the observational record which began in 1900, and is a 5.4 degrees Fahrenheit (3 degrees Celsius) increase since the beginning of the 20th Century.

Sea ice: Maximum Arctic Ocean sea ice extent, which occurred February 25, 2015, 15 days earlier than average, was the lowest extent recorded since records began in 1979.

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Snow cover: While Arctic-wide terrestrial snow cover extent in April was above average, June snow cover in both the North American and Eurasian parts of the Arctic was the second lowest in the satellite record that began in 1967.

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Greenland ice sheet: For the first time since the exceptional melt of 2012, significant melting (more than 50 percent of the area) occurred on the surface of the Greenland ice sheet in 2015. Melt season was 30 to 40 days longer than average in western, northwestern and northeastern Greenland, but was close to or below average elsewhere on the ice sheet.

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Arctic Ocean temperature: As sea ice retreats in summer, sea surface temperature (SST) in all the seas of the Arctic Ocean is increasing.

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Arctic Ocean productivity: Melting and retreat of sea ice during spring is leading to an increase in sunlight reaching the upper layers of the ocean, promoting photosynthesis and stimulating the growth of algae (tiny marine plants which form the base of the food chain).

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Vegetation: Arctic tundra greenness, a measure of live vegetation (grasses, sedges, mosses, lichens, shrubs) productivity and biomass, had been increasing over the past two to three decades, as indicated by the satellite record. However, for reasons that remain to be identified, tundra greenness has been declining, or browning, consistently for the past two to four years.

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Walrus habitat: The decline in sea ice is dramatically changing the habitat for walruses--large marine mammals that traditionally use sea ice for mating, giving birth to young, finding food and shelter from storms and predators. In recent years, large numbers of walrus have been forced to haul out on land in northwest Alaska. This behavior, documented through aerial surveys, has created problems such as overcrowding which has led to stampedes that have killed calves, and difficulty finding food. Walruses must travel longer distances to the ice edge to find food.

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Subarctic fish: Scientists from Norway and Russia drew on annual ecosystem surveys from the Barents Sea from 2004 to 2013 to show a northward movement of subarctic fish species such as cod, beaked redfish and long rough dab, into Arctic waters. These predators may pose potential problems for smaller Arctic fish that must now face these new warmer-water predators.

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Freshwater discharge: In 2014, and for the first seven months of 2015, the combined discharge of fresh water from eight Eurasian and North American rivers into the Arctic Ocean was 10 percent greater than the discharge in the decade of 1980-89. Scientists attribute the rise in discharge to increasing precipitation linked to global warming.

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In 2006, NOAA's Climate Program Office introduced the State of the Arctic Report which established a baseline of conditions at the beginning of the 21st century. It is updated annually as the Arctic Report Card to document the often-quickly changing conditions in the Arctic. To view this year's report, visit http://www.arctic.noaa.gov/reportcard/.