Pliocene Climate variability at Lake El'gygytgyn, NE Arctic Russia, western Beringia

The new record from Lake El'gygytgyn, NE arctic Russia provides the first complete record of Pliocene climate change from the terrestrial Arctic. Lake El'gygytgyn evidence shows 3.6-3.4 Ma ago summer temperatures were ~8oC warmer than today when pCO2 was ~400 ppm. Multiproxy evidence suggests extreme warmth and polar amplification during the middle Pliocene with low amplitude changes between cold and warm Milankovitch cycles consistent with the LR stack. Sudden stepped cooling events during the Pliocene-Pleistocene transition recorded at Lake E are consistent with marine proxies from the North Pacific and North Atlantic suggesting that polar amplification was recorded across the northern hemisphere in both marine and Arctic terrestrial environments. Summers warmer than present Arctic persisted until ~2.2 Ma, after the onset of Northern Hemispheric glaciation. Our data are consistent with sea-level records and other proxies indicating that Arctic cooling was really insufficient to support large-scale ice sheets until the early Pleistocene.