NOAA report: Long-term Arctic warming trends continue

Unprecedented warmer air temperature over the Arctic triggered extensive melting in the sea ice and land-based snow cover this fall, according to a new report from the National Oceanic and Atmospheric Administration.

The 11th annual Arctic Report Card, which is based on research by 61 scientists in 11 countries, shows the continuation of long-term Arctic warming trends.

I recently wrote in another blog post about two New Zealand glaciers — Franz Josef and Fox glaciers — that have been melting at an accelerated rate in recent years. Franz Josef Glacier has retreated by nearly a half mile since 2008.

“Rarely have we seen the Arctic show a clearer, stronger or more pronounced signal of persistent warming and its cascading effects on the environment than this year,” Jeremy Mathis, director of NOAA’s Arctic Research Program, said in a statement. Here are some of the key findings of the report:

Surface air temperature: Average annual air temperature over land was the highest on record, up 6.3 degrees Fahrenheit since 1900. Arctic air temperatures are rising twice as fast as global temperatures. For October-November, the highest average temperature was 25 degrees Fahrenheit above the long-term norm in Northern Canada.

Snow cover: The spring snow cover set a record low in the North American Arctic, falling below 1.5 million square miles for the first time since satellite tracking began in 1967. NOAA researchers noted that snow cover patterns are “strongly related” to surface air temperature trends.

Greenland ice sheet: The Greenland ice sheet continued to shrink, with the melt starting at the second earliest in the 37-year record.

Sea ice: The extent of Arctic sea ice from mid-October to late November was the lowest in 37 years of satellite records. The November ice extent was 18 percent less than the long-term average for that month. Arctic ice is thinning, with more stable, multi-year ice comprising 22 percent of the ice cover vs. 45 percent in 1985. Researchers noted that warmer air and ocean surface temperatures helped delay this fall’s freeze.

Ocean temperature: Sea surface temperature in August was 9 degrees Fahrenheit higher than the average from 1982 to 2010 in the Barents and Chukchi seas and off Greenland’s east and west coasts.

Ocean acidification: More carbon dioxide emissions appears to affect the Arctic Ocean more than other oceans. Such ocean acidification is expected to add more stress to marine fisheries, particularly those that need calcium carbonate to build shells, and affect Arctic communities that depend on fisheries.

Ocean productivity: Springtime melting and retreating ice let more sunlight reach the Arctic Ocean’s upper layers, stimulating widespread blooms of algae and other marine plants that form the base of the marine food chain.

Carbon release: The warming tundra releases more carbon into the atmosphere than it absorbs. Twice as much organic carbon is locked in the northern permafrost as in the Earth’s atmosphere. If permafrost melt releases that carbon, it could have “profound effects” on weather and climate in the Arctic and everywhere.

The above highlights are for peer-reviewed research through September, except where noted for non-peer reviewed data through late November.

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