J. Richter-Menge1, J. E. Overland2, J. T. Mathis3, E. Osborne3
1University of Alaska Fairbanks, Institute of Northern Engineering, Fairbanks, AK, USA
2National Oceanic and Atmospheric Administration, Pacific Marine Environmental Laboratory, Seattle, WA, USA
3National Oceanic and Atmospheric Administration, Arctic Research Program, Silver Spring, MD, USA
The Arctic Report Card (www.arctic.noaa.gov/Report-Card/), going into its 12th year, considers a range of environmental observations throughout the Arctic, and is updated annually. As in previous years, the 2017 update highlights the changes that continue to occur in, and among, the physical and biological components of the Arctic environmental system.
Arctic conditions in 2017 provide an excellent example of the need to assess observations in the context of longer-term records. After a very warm Arctic-wide autumn 2016, spring and summer 2017 had near average air temperatures relative to the 1981-2010 climatology. These spring/summer conditions were reminiscent of conditions before the long-term temperatures increases that began in the 1990s. These 'relatively cool' temperatures in spring and summer 2017 contributed to a rebound in the snow cover extent in Eurasia during May and June, a slowing of the summer sea ice loss, and below-average melt extent for the Greenland ice sheet.
Taken alone, observations made in spring and summer 2017 might encourage a relaxation in the concerns over environmental conditions in the Arctic. However, when taken in context, there are many strong signals that continue to indicate that the Arctic environmental system has reached a 'new normal'. While modulated by natural variability in regional and seasonal fluctuations, this 'new normal' is characterized by Arctic air temperatures that are warming at double the rate of the global temperature increase. Accordingly, there are pronounced decade-long declines in the extent and volume of the sea ice cover, the extent and duration of the winter snow cover, and the mass of the Greenland Ice Sheet and Arctic glaciers. Temperatures are increasing in the surface of the Arctic Ocean, contributing to later formation of the sea ice cover in the autumn. Temperatures are also increasing in the permafrost on the adjacent continents. Arctic paleo-reconstructions, which extend back millions of years, indicate that the magnitude and pace of the 21st century sea-ice decline and surface ocean warming is unprecedented in at least the last 1,500 years and likely much longer.
The persistence of the environmental conditions that define the Arctic's 'new normal' has enabled increases in Arctic Ocean primary productivity, which forms the basis of the marine food web. Additionally, above ground vegetation is also expanding and affecting hydrological dynamics, carbon and nutrient cycling, the surface energy balance, and the habits of wild and domesticated plant eaters. The pervasive changes in the environment influence resource management protocols, including those established for fisheries and wildfires, and directly affecting the people living in Arctic communities. The unprecedented rate and global reach of these changes highlight the pressing need to prepare for and adapt to the New Arctic, enabled by more effective and timely communication of observations to scientists, policymakers, and residents.
Detailed Highlights from Arctic Report Card 2017
- The second warmest (after 2016) surface air temperature anomaly (+1.6° C relative to 1981-2010) north of 60° N since the year 1900 was observed between October 2016 and September 2017.
- On the 7th of March 2017 satellites observed the lowest winter maximum in sea ice on record (1979-present). The March maximum was 8% lower and the September minimum was 25% lower than the 1981-2010 average sea ice extent. The sea ice cover continues to be relatively young and thin with multiyear ice (more than 1 year old) comprising only 21% of ice cover in 2017 compared to 45% in 1985.
- Sea surface temperature in the Chukchi Sea, northwest of Alaska, has experienced the largest warming trend: ~0.7° C per decade since 1982. In August 2017 the Barents and Chukchi seas experienced surface temperatures up to 4° C warmer than the 1982-2010 average.
- The most pronounced increasing trends in ocean primary productivity during the 2003-2017 period were observed in the Barents Sea and Eurasian Arctic regions. Long-term records reveal that years with elevated ocean productivity levels are often associated with earlier sea ice breakup during the spring/summer transition.
- The downward trend in total ice mass of the Greenland ice sheet averaged over the last 15 years is estimated at 264-270 Gt/yr. The spatial extent of melt for the period June, July and August 2017 reached a maximum of 32.9%, marking the lowest maximum extent since 1996.
- Spring snow cover extent over Eurasia in May 2017 was the 2nd highest recorded by satellite observations dating back to 1967. May and June snow cover extent anomalies over the Eurasian Arctic mark the first positive anomalies observed since 2005 and 2004, respectively.
- Tundra greenness has increased substantially throughout the Arctic during 2015 and 2016 (the most recent year with a complete data set) following 3-4 years of continuous declines. Peak tundra greenness for 2016 ranks 4th (entire Arctic), 9th (Eurasian Arctic), and 3rd (North American Arctic) in the context of the 35-year satellite record.
- Permafrost temperatures in 2016 (the most recent set of complete observations) at many observation sites around the Arctic were among the highest on record (as long as 1978-present, but duration of records vary). Increases in permafrost temperature, since 2000, have been greatest in cold permafrost of the Alaskan Arctic, Canadian high Arctic, and Svalbard.
The 12 contributions to Arctic Report Card 2017, representing the collective effort of an international team of 85 researchers in 12 countries, and are based on published and ongoing scientific research. Financial support for the Arctic Report Card is provided by the Arctic Research Program in the NOAA Climate Program Office. Preparation of Arctic Report Card 2017 was directed by the NOAA Arctic Research Program, with editorial assistance by researchers from the NOAA Pacific Marine Environmental Laboratory and the University of Alaska Fairbanks (via research sponsored by the Cooperative Institute for Alaska Research with funds from the NOAA Administration under cooperative agreement NA13OAR4320056 with the University of Alaska). Independent peer-review of the scientific content of Arctic Report Card 2017 was facilitated by the Arctic Monitoring and Assessment (AMAP) Program of the Arctic Council.
November 17, 2017