500-year paleoclimate record inferred from Greenland Juniper wood contextualizes current climate warming

Contextualising Arctic warming and sea ice loss requires high-resolution climate proxy archives, which are rare across the high-northern latitudes. Here, we present annually resolved and absolutely dated tree-ring width measurements of living and dry juniper (Juniperus communis) shrubs, as well as herbarium specimens, all from southern Greenland. We develop a continuous chronology for 1526-2023 CE that correlates at 0.67 with mean June‒August temperatures (p < 0.001). We then identify reduced cell wall lignification (i.e., "Blue Rings") during exceptionally cold summers that often occurred after large volcanic eruptions, with Laki in 1783 and Tambora in 1815 CE causing the strongest responses. Our findings at the interface of dendroclimatology and wood anatomy provide a high-resolution paleoclimate record for southern Greenland that places anthropogenic warming in the context of natural climate variability.