Arctic Report Card: It’s Getting Dark in Here

December 18, 2014

Seth Borenstein of AP reports from AGU.

AP:

In the spring and summer of 2014, Earth’s icy northern region lost more of its signature whiteness that reflects the sun’s heat. It was replaced temporarily with dark land and water that absorbs more energy, keeping yet more heat on already warming planet, according to the Arctic report card issued Thursday.

Spring snow cover in Eurasia reached a record low in April. Arctic summer sea ice, while not setting a new record, continued a long-term, steady decline. And Greenland set a record in August for the least amount of sunlight reflected in that month, said the peer-reviewed report from the National Oceanic and Atmospheric Administration and other agencies.

Overall, the report card written by 63 scientists from 13 countries shows few single-year dramatic changes, unlike other years.

“We can’t expect records every year. It need not be spectacular for the Arctic to continue to be changing,” said report lead editor Martin Jeffries, an Arctic scientist for the Office of Naval Research, at a San Francisco news conference Wednesday.

The Arctic’s drop in reflectivity is crucial because “it plays a role like a thermostat in regulating global climate,” Jeffries said, in an interview. As the bright areas are replaced, even temporarily, with dark heat-absorbing dark areas, “That has global implications.”

The world’s thermostat setting gets nudged up a bit because more heat is being absorbed instead of reflected, he said.

NOAA – Arctic Report Card:

The warming Arctic atmosphere was strongly connected to lower latitudes in early 2014 causing cold air outbreaks into the eastern USA and warm air intrusions into Alaska and northern Europe

Snow cover extent in April 2014 in Eurasia was the lowest since 1967 and sea ice extent in September was the 6th lowest since 1979.

Polar bears numbers in western Hudson Bay and the southern Beaufort Sea are decreasing in connection with a decrease in the availability of sea ice.

The tundra is “browning” as the length of the growing season is decreasing in Eurasia, but maximum tundra greenness and biomass are increasing across the Arctic.

Sea surface temperatures and primary production are increasing as the sea ice retreats throughout the Arctic Ocean.

On the Greenland ice sheet nearly 40% of the surface experienced melting conditions in summer 2014 and the albedo (reflectivity) reached a new record low value in August.

Albedo, also referred to as reflectivity, is the ratio of reflected solar radiation to total incoming solar radiation. Here it is derived from the Moderate-resolution Imaging Spectroradiometer (MODIS, after Box et al. 2012). In summer 2014, albedo was below average over most of the ice sheet (Fig. 3.4a) and the area-averaged albedo for the entire ice sheet was the second lowest in the period of record that began in 2000 (Fig. 3.4b). The area-averaged albedo in August was the lowest on record for that month (Fig. 3.4c). August 2014 albedo values were particularly low at high elevations; such low values have not previously been observed so late in the summer. The observed albedo in summer 2014 continues a period of increasingly negative and record low albedo anomaly values (Box et al. 2012, Tedesco et al. 2011, 2013a, Dumont et al. 2014).

2 Responses to “Arctic Report Card: It’s Getting Dark in Here”

  1. Gingerbaker Says:

    Man, you think it’s hot now? Wait until that Arctic ice is gone in the summer.

    We might see truly goofy weather patterns, with full equatorial heat descending on once-frozen permafrost. Who knows?


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