These 21 Last Interglacial (LIG) summer surface air temperature (SSAT) observations were compiled to assess LIG Arctic sea ice (Guarino et al 2020). Twenty of the observations were also previously used in the IPCC-AR5 report. Each observation is thought to be of summer LIG air temperature anomaly relative to present day and is located in the circum-Arctic region. All sites are from north of 51N. There are 7 terrestrial based temperature records; 8 lacustrine records; 2 marine pollen-based records; and 3 ice core records included in the original compilation. This compilation includes 1 additional ice core record. This work was funded by NERC standard research grant nos. NE/P013279/1 and NE/P009271/1.

A 9.5 m long gravity core (PS100-198GC) and 44 cm box core (PS100-198BC) were collected from the same location from a water depth of 398 m from the Norske Trough on the inner continental shelf of NE Greenland. The material was collected during cruise PS100 of the RV Polarstern to NE Greenland in 2016 to investigate the interaction between the Northeast Greenland Ice Stream (NEGIS) and ocean circulation through the Holocene. The following parameters were measured: GEOTEK Multi-Sensor Core Logger (MSCL, gravity core only, Durham University, DU); foraminiferal faunal analysis (DU) and stable isotopes (oxygen and carbon, measured at the NERC National Environmental Isotope Facility); carbon analysis (box core only, DU); dinoflagellate cysts and other palynomorphs (box core only, Geological Survey of Denmark and Greenland, GEUS); sea ice biomarkers (IP25 and HBI III, box core only, University of Helsinki). This research was supported by the following grants: Alfred Wegener Institute (AWI) grant for ship time: AWI_PS100_01; NERC standard grant: NE/N011228/1; NERC National Environmental Isotope Facility grant: IP-1816-0618; NERC Radiocarbon Facility grant: NRCF010001, allocation no. 2113.0418; Independent Research Council Denmark grant to Sofia Ribeiro: 9064-00039B.