SAN FRANCISCO, CA, DECEMBER 15, 2015 — News from the Arctic hasn’t gotten any better in the 10 years since NOAA began producing an annual Arctic Report Card, and this year’s collection of results and essays is no exception.
“The Arctic is warming twice as fast as other parts of the planet,” said Rick Spinrad, NOAA chief scientist, adding “what happens in the Arctic doesn’t stay in the Arctic.”
The average Arctic temperature change, 2.3 degrees F (1.3 degrees C) above average, continues to outpace change in the rest of the world, a phenomenon known as “Arctic amplification.” Since the beginning of the 20th century, Arctic warming is now a hefty 5.4 degrees F (3.0 degrees C), leading to significant changes to the region.
“One could argue that the trailing indicators in the Arctic are the leading indicators for the rest of the climate,” Spinrad said.
Two items from the report, which was written by 72 authors from 11 different countries, were highlighted here: a mysterious browning of Arctic tundra, and the impact of change on walruses.
“Greenness” – a measure of photosynthetic activity by satellites — has been declining since 2001 (see Figure below), with a sharp drop-off in the past two to four years, running counter to the notion that more carbon dioxide is unequivocally good for plant life.
“We don’t have an answer yet” to the declining greenness, said Howard Epstein, a scientist from the University of Virginia. “A drop in greenness for any given year isn’t alarming, or even two years in a row.” But four years makes for a noticeable trend.
Epstein said the decrease may be caused by changes in snow that can have dramatic effects on vegetation, atmospheric conditions, aerosols, changes in cloudiness, or other disturbances on the landscape. Vegetation provides insulation to permafrost, the carbon-rich, thick layer of soil that remains frozen over the entire year, so its waning could have larger effects if these soils melt and release carbon, adding to the enhanced greenhouse effect that’s causing global warming.
Vegetation where there was once snow also decreases the reflectivity of sunlight, meaning more heating at the surface and so more heating of air.
New Walrus Behavior … ‘hauling out’
The decline of Arctic sea ice means walruses can’t fish as often from ice edges as in the past, she explained, causing the animals to make feeding trips of up to 110 miles (180 km). This behavior causes problems of overcrowding, which has led to stampedes that have killed calves. (Walrus populations overall have benefited from a hunting enacted in 1952.)
The “Reproductive behaviors of walruses are clearly changing,” Kovacs said, and “the Arctic’s carrying capacity is clearly declining.”
Fish populations are also seen to be clearly changing in the Barents Sea, as cod, beaked redfish, and long rough dab move northward to cooler waters, displacing smaller fish. The discharge of freshwater rivers into the Arctic was, in 2014 and the first half of 2015, 10 percent greater than during the period of 1980 to 1989, believed to be from increasing precipitation in a warming climate.
Limiting average global temperature change to the recent Paris Agreement goal of 2 degrees C (3.6 degrees F) would mean an Arctic temperature increase of four to five degrees Celsius (7-9 degrees F) during winter months, said James Overland of NOAA’s Pacific Marine Environmental Laboratory.