Fig. 4: Regional environmental reconstructions spanning the last millennium.
From: Destabilisation of the Subpolar North Atlantic prior to the Little Ice Age
a April sea ice index from the North Icelandic Shelf based on the relative abundance of IP25, a biomarker synthesised by sea-ice diatoms32. b Oxygen isotope record from the planktonic foraminifera Neogloboquadrina pachyderma reflecting summer near-surface temperatures on the Norwegian margin35. c Oxygen isotope record as a proxy for SSTs on the Norwegian margin36. d August SST on the Eastern Norwegian Sea inferred from diatom assemblages38. e Annual SST in South Iceland based on paired Mg/Ca–δ18O measurements from the planktonic foraminifera Globorotalia inflata41. f Summer SST in North Iceland based on diatom assemblages39. g Atlantic Multidecadal Variability Index (AMVI) reconstructed from Titanium content from a laminated sedimentary record from the Canadian Arctic42. h Neodymium isotopic composition (ɛNd) in deep-sea corals from the north-eastern Atlantic44, dating uncertainties are indicated by the horizontal error bars. Higher ɛNd isotopic values indicate a decreased influence of Labrador Sea Water. i Iceland-Scotland Overturning Water (ISOW) sortable silt average size (\(\overline{{SS}}\))18, faster flows indicate a weakened influence of Labrador Sea water. j Sortable silt average size (\(\overline{{SS}}\)) as a proxy for variations in the strength of the Norwegian Atlantic Slope Current (NwASC)45. k Reconstructed solar modulation parameter (Φ) as a proxy for solar activity62. l Global volcanic forcing reconstructed from sulfate composite ice core records57. The bold lines in some of the records were obtained by computing 3 to 20 year moving averages to improve visibility. The yellow and blue shaded intervals correspond to the first and second destabilisation events respectively. The hatched region comprises the initial window interval for each episode. The interval comprising the sea ice anomaly event is represented by the blue square.
