Arctic Report Card 2020 The sustained transformation to a warmer, less frozen and biologically changed Arctic remains clear DOI: 10.25923/MN5P-T549X R.L. Thoman, J. Richter-Menge, and M.L. Druckenmiller; Eds. December 2020 Richard L. Thoman, Jacqueline Richter-Menge, and Matthew L. Druckenmiller; Editors Benjamin J. DeAngelo; NOAA Executive Editor Kelley A. Uhlig; NOAA Coordinating Editor www.arctic.noaa.gov/Report-Card How to Cite Arctic Report Card 2020 Citing the complete report or Executive Summary: Thoman, R. L., J. Richter-Menge, and M. L. Druckenmiller, Eds., 2020: Arctic Report Card 2020, https://doi.org/10.25923/mn5p-t549. Citing an essay (example): Frey, K. E., J. C. Comiso, L. W. Cooper, J. M. Grebmeier, and L. V. Stock, 2020: Arctic Ocean primary productivity: The response of marine algae to climate warming and sea ice decline. Arctic Report Card 2020, R. L. Thoman, J. Richter-Menge, and M. L. Druckenmiller, Eds., https://doi.org/10.25923/vtdn-2198. (Note: Each essay has a unique DOI assigned) Front cover photo credits Center: Yamal Peninsula wildland fire, Siberia, 2017 – Jeffrey T. Kerby, National Geographic Society, Aarhus Institute of Advanced Studies, Aarhus University, Aarhus, Denmark Top Left: Large blocks of ice-rich permafrost fall onto the beach along the Laptev Sea coast, Siberia, 2017 – Pier Paul Overduin, Alfred Wegner Institute for Polar and Marine Research, Potsdam, Germany Top Right: R/V Polarstern during polar night, MOSAiC Expedition, 2019 – Matthew Shupe, Cooperative Institute for Research in Environmental Sciences, University of Colorado and NOAA Physical Sciences Laboratory, Boulder, Colorado, USA Mention of a commercial company or product does not constitute an endorsement by NOAA/OAR. Use of information from this publication concerning proprietary products or the tests of such products for publicity or advertising purposes is not authorized. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Oceanic and Atmospheric Administration. NOAA Arctic Report Card 2020 Table of Contents 2020 Headlines.............................................................................................................................................. 2 Executive Summary ....................................................................................................................................... 4 15 Years of Arctic Observation: A Retrospective.............................................................................................. 8 The Observational Foundation of the Arctic Report Card – a 15-Year Retrospective Analysis on the Arctic Observing Network (AON) and Insights for the Future System .................................................................. 12 Surface Air Temperature ............................................................................................................................. 21 Terrestrial Snow Cover ................................................................................................................................ 28 Greenland Ice Sheet .................................................................................................................................... 35 Sea Ice ......................................................................................................................................................... 44 Sea Surface Temperature............................................................................................................................ 54 Arctic Ocean Primary Productivity: The Response of Marine Algae to Climate Warming and Sea Ice Decline ........................................................................................................................................................ 59 Tundra Greenness ....................................................................................................................................... 68 Glaciers and Ice Caps Outside Greenland ................................................................................................... 79 Bowhead Whales: Recent Insights into Their Biology, Status, and Resilience ........................................... 87 Coastal Permafrost Erosion ......................................................................................................................... 96 Wildland Fire in High Northern Latitudes ................................................................................................. 105 The MOSAiC Expedition: A Year Drifting with the Arctic Sea Ice .............................................................. 115 Integrating Models and Observations to Better Predict a Changing Arctic Sea Ice Cover ....................... 123 New Arctic Research Facility Opens Door to Science Collaborations ....................................................... 130 Authors and Affiliations ............................................................................................................................ 135 1 NOAA Arctic Report Card 2020 2020 Headlines The sustained transformation to a warmer, less frozen and biologically changed Arctic remains clear Extreme warm air temperatures in the Eurasian Arctic illustrate significant region-wide effects of year- to-year variability and connections across the Arctic environment. Highlights • The average annual land surface air temperature north of 60° N for October 2019-September 2020 was the second highest on record since at least 1900. Record warm temperatures in the Eurasian Arctic were associated with extreme conditions in the ocean and on the land. In the oceans • Sea ice loss in spring 2020 was particularly early in the East Siberian Sea and Laptev Sea regions, setting new record lows in the Laptev Sea for June. The end of summer sea ice extent in 2020 was the second lowest in the 42-year satellite record, with 2012 being the record minimum year. • August mean sea surface temperatures in 2020 were ~1-3°C warmer than the 1982-2010 August mean over most of the Arctic Ocean, with exceptionally warm temperatures in the Laptev and Kara seas that coincided with the early loss of sea ice in this region. • During July and August 2020, regional ocean primary productivity in the Laptev Sea was ~2 times higher for July and ~6 times higher for August compared to their respective monthly averages. • Bowhead whales have been a staple resource for coastal Indigenous peoples for millennia and are uniquely adapted for the arctic marine ecosystem. The Pacific Arctic population size has increased in the past 30 years likely due to increases in ocean primary production and northward transport of the zooplankton they feed on. • Shifts in air temperatures, storminess, sea ice and ocean conditions have combined to increase coastal permafrost erosion rates, in regions where a high proportion of Arctic residents live and industrial, commercial, tourist and military activities are expanding. On the land • The exceptional warm spring air temperatures across Siberia resulted in record low June snow cover extent across the Eurasian Arctic, as observed in the past 54 years. • Extreme wildfires in 2020 in the Sakha Republic of northern Russia coincided with unparalleled warm air temperatures and record snow loss in the region. • Since 2016, tundra greenness trends have diverged strongly by continent, declining sharply in North America but remaining above the long-term average in Eurasia. • From September 2019 to August 2020, the Greenland Ice Sheet experienced higher ice loss than the 1981-2010 average but substantially lower than the record 2018/19 loss. • Glaciers and ice sheets outside of Greenland have continued a trend of significant ice loss, dominated largely by ice loss from Alaska and Arctic Canada. 2 NOAA Arctic Report Card 2020 Observing Arctic change • Advancements in the integration of models and observations have increased the skill and utility of Arctic sea ice predictions on seasonal to decadal to century timescales. • Important additions to the Arctic Observing Network (AON) systems and data products and advancements in process-level understanding have improved the quality and accessibility of information used to produce the Arctic Report Card. • The unique Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) project concluded a historic, international, yearlong expedition into the Arctic ice pack in September 2020, collecting a legacy dataset that aims to advance the understanding, modeling and predicting of Arctic environmental change. • Opening of the new NOAA Barrow Observatory, near Utqiaġvik, Alaska, enables the continuation of nearly half a century of atmosphere and terrestrial in situ observations. 3 NOAA Arctic Report Card 2020 Executive Summary DOI: 10.25923/mn5p-t549 R. L. Thoman1,2, J. Richter-Menge3, and M. L. Druckenmiller4 1Alaska Center for Climate Assessment and Policy, University of Alaska Fairbanks, Fairbanks, AK, USA 2International Arctic Research Center, University of Alaska Fairbanks, Fairbanks, AK, USA 3Institute of Northern Engineering, University of Alaska Fairbanks, Fairbanks, AK, USA 4National Snow and Ice Data Center, University of Colorado Boulder, Boulder, CO, USA The Arctic Report Card (ARC) provides an annual update on the state of the Arctic's climate and environment as well as highlights of Arctic science news of the past year. ARC2020 features 16 essays, 11 of which provide updates on a wide