The Terrestrial Snow Cover essay authors thank the Rutgers Global Snow Lab, the U.S. National Ice Center and the Canadian Meteorological Centre for snow data sets, and the National Snow and Ice Data Center for sea ice extent data from the Sea Ice Index.
The Greenland Ice Sheet essay authors thank a number of organizations for support for the numerous observations described. Marco Tedesco acknowledges NSF grants PLR1304807 and ANS 0909388, and NASA grant NNX1498G. The K-transect program is funded by Utrecht University, the Netherlands Polar Program of NWO/ALW and a Spinoza grant awarded to J. Oerlemans. PROMICE is funded by the Danish Energy Agency (DANCEA) programme; data are available at www.promice.dk.
The Tundra Greenness essay authors thank the following for their support: NSF Office of Polar Programs grants ARC-0908444, ARC-0908602 and ARC-0902030; NSF ArcSEES grant 1233854; NASA Pre-ABoVE grant NNX13AM20G, ABoVE grant NNX15AT76A and Land Cover Land Use Change (LCLUC) grant NNX14AD906; and UK Natural Environmental Research Council grant NE/M016323/1
The River Discharge essay authors thank the U.S. Geological Survey (Yukon), Water Survey of Canada (Mackenzie) and Roshydromet (Severnaya Dvina, Pechora, Ob', Yenisey, Lena, and Kolyma) for the discharge data used here. Most of these data are now available through the Arctic Great Rivers Observatory (www.arcticgreatrivers.org).
Karen Frey, first author of the Arctic Ocean Primary Productivity essay acknowledges NASA grant NNX14AH61G and NSF grants ARC-0804773 and ARC-1107645.