10/21/25 Nature Geoscience:
The sensitivity of terrestrial Arctic climate during the Late Miocene remains poorly understood, despite this interval marking the transition towards a cooler, more variable global climate and the prelude to Northern Hemisphere glaciation. Here we present a Late Miocene terrestrial proxy record, developed through the analysis of speleothems, from eastern North Greenland (Kalaallit Nunaat). Growth periods indicate multiple episodes of permafrost absence between ~10 and 5 Ma, suggesting mean annual air temperatures ~14 °C higher than present coinciding with atmospheric CO2 concentrations above ~310 ppm and local sea surface temperature anomalies >2 °C higher than present. Such moderate thresholds for permafrost absence highlight the climate sensitivity of North Greenland. Spikes in siliciclastic-derived trace elements ~6.3 and ~5.6 Ma are interpreted as terrestrial indicators for Late Miocene ephemeral glaciers in North Greenland. Climate variability recorded during speleothem growth periods was predominantly forced by obliquity,
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