Arctic Temperature Highest on Record

http://www.climatecentral.org/news/arctic-temperature-highest-on-record-19820

By Andrea Thompson
Dec. 15, 2015

The Arctic has just received its yearly checkup from a group of international scientists, and the patient isn’t looking well.

The region continues to be one of the fastest warming on the planet. From October 2014 to September 2015, it had the warmest average temperature on record going back to 1900, as the planet heads toward its warmest year on record. That accelerated warming has repercussions in the form of downward-spiraling sea ice coverage, melting of the massive Greenland Ice Sheet, and reduced summer snow cover.

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The Arctic has been warming at more than twice the rate of the globe as a whole, with average temperatures today 5.4°F (3°C) above what they were at the beginning of the 20th century, compared to an estimated global average of 1.8°F (1°C) over the same time.

“We know this is due to climate change,” Rick Spinrad, chief scientist for the U.S. National Oceanic and Atmospheric Administration, said. The excess heat trapped in the atmosphere from accumulating greenhouse gases leads to changes in the Arctic that cause still more warming, a process called Arctic amplification.

Temperatures from October 2014 to September 2015 this year were 2.3°F (1.3°C) above average — the highest in an observational record going back to 1900.

That warmth influenced the extent of sea ice across the Arctic over the year: The maximum area that comes at the end of the cold winter months was the lowest on record this year, and it came 15 days earlier than average. At the opposite extreme, the end-of-summer minimum was the fourth lowest on record — the September minimum has declined at a rate of 13.4 percent per decade compared to the 1981-2010 average.

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While Arctic-wide snow cover was above-average in April, it hit the second lowest area on record for June, pointing to continued early spring snowmelt.

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These dramatic changes to the Arctic are expected continue and compound moving forward this century. Even with the recent international agreement to limit warming to a global average of 2°C (3.6°F), Arctic temperatures will warm much more than that. By mid-century, winters in the Arctic could warm by 4° to 5°C, with large sea ice-free areas, report co-author Jim Overland, of NOAA’s Pacific Marine Environmental Laboratory, said.

“We’re already in the adaptation mode,” he said.

But if greenhouse gas emissions are reduced enough, the change in the Arctic “will slow down and have a big effect in the second half of the century,” possibly even heralding the return of more extensive summer sea ice.

While the broad brush strokes of Arctic warming continue to be seen year after year, the report card is important because “almost every year we see new surprises on the rapidity of the types of changes we’re seeing,” Overland said.

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