Cultural Implications of Out-of-Phase Weather across northern Alaska after 500 CE: Regional Variability during the Medieval Climate Anomaly and Little Ice Age

Abstract:

From a global perspective, a diverse mélange of paleoclimate data reveal that Northwest Alaska is partially out of phase with northwest Europe, witnessing cooler periods during the Medieval Climate Anomaly ca. CE 1000 and warmer conditions in the 16^th and 17^th centuries. The search for climatic forcers in northern Alaska relies on integration of data drawn from tree-rings, lacustrine varves and moraines, diatoms, beach ridges and dunes. At Cape Espenberg, northern Seward Peninsula, a 1500-year reconstruction of settlement, landscape evolution and climatic variability employs >100 ¹⁴C ages from accreting dunes with shell-laden storm beds, intercalated driftwood and superimposed soils, archaeological sites and marsh peats within swale ponds. Large storms occurred along the Chukchi Sea from Cape Espenberg and Deering (Kotzebue Sound) to Point Barrow prior to 1000 CE, and at decadal intervals during the Little Ice Age (LIA) from 1300 to 1700. Architecural driftwood logs from several excavated houses capped by sand dunes yield several ¹⁴C dated floating chronologies covering intervals from 700 to 1700, suggest the identification of cooler intervals 800 to 1000 and intermittently after 1300. Peat aggradation followed isolation from the sea from 500 onward, and was interrupted by two pulses of fresh water, one ca. 1300 and a second ca. 1800, with diatoms suggesting relative aridity during the LIA. The occupation history of Cape Espenberg generally follows dune growth, and may be inversely related to cooler temperatures.