Isotopic evidence for Holocene January air temperature variability on the East Chukotka Peninsula

Abstract

Ice‐wedge ice can provide a valuable record of past winter climate variability at high latitudes yet to date this proxy has been applied only sparsely across the Chukotka region of Siberia. Here we present data from eight ice‐wedges at four sites across a 600‐km transect in Eastern Chukotka which we use to reconstruct regional Holocene winter paleotemperature. The Holocene age of ice‐wedges was established by radiocarbon dating of peat surrounding individual ice‐wedges. Our suite of radiocarbon ages suggests that the studied ice‐wedges formed between 12.9–11.8 and 3–2.5 cal ka BP. δ18O and δ2H values from ice‐wedge ice indicate that in coastal areas of Eastern Chukotka mean January air temperatures in the first half of the Holocene were on average 2–3°С lower than modern values, a finding that corresponds well with winter climate reconstructions for the other areas of Beringia. The variability of reconstructed mean January air temperatures in the study area did not exceed 2–4°C during the early to mid‐Holocene.

Winter air temperature during the Holocene optimum in the north‐eastern part of the east European plain based on ice wedge stable isotope records

“…According to these data winter air temperatures during the early part of the HTM were generally lower than present. In the coastal areas of Eastern Chukotka, mean January air temperatures during the early to mid‐Holocene were on average 2–3°С lower than modern values, corresponding well with winter climate reconstructions for other areas of Beringia . In the Chara River Basin, northern Transbaikalia, reconstructed mean winter temperatures of the cold stages of the Holocene optimum (10–7.5 ka BP) may have been 2–3°C lower and mean January temperature 3–4°C lower than modern ones .…”

“…Intensive peat accumulation accompanied by ice wedge growth was typical during the Holocene optimum noted from northern regions of the East European Plain to the east of the Chukotka Peninsula . Thick peatlands with syngenetic ice wedges aged to the Holocene optimum are widespread in the northern part of Western Siberia.…”

“…A strong correlation between the stable isotope composition of ice wedge ice and winter air temperature has been shown for most sites of northern Siberian and European North permafrost, indicating a minor influence of isotope fractionation in winter precipitation before their preservation in ice wedges. In the last three decades this approach has been successfully applied to the reconstruction of Late Pleistocene and Holocene air winter temperatures in Siberia …”

Holocene ice wedges of the Kolyma Lowland and January paleotemperature reconstructions based on oxygen isotope records

“…64 For the eastern coastal regions of Chukotka, a clear positive trend of winter air temperature from 11-7 to 4-3 cal kyr BP was established. 65,66 In Arctic regions of Alaska and Canada, ice wedge growth in the early to mid-Holocene was very limited due to deep thawing and thermokarst development. [67][68][69] For the Blackstone Plateau, central Yukon, during the early to mid-Holocene ice wedges were inactive and re-initiated around 6,360 cal yr BP, with a peak in activity between 3,980 and 920 cal yr BP.…”

Holocene January paleotemperature of northwestern Siberia reconstructed based on stable isotope ratio of ice wedges

“…6 In recent decades, stable oxygen and hydrogen isotope data from ice wedges representing a paleoarchive of winter air temperatures have been used to reconstruct winter climatic conditions in the Arctic regions. [7][8][9][10][11][12][13] Since ice wedges are highly sensitive to increasing ground temperature and increasing active layer thickness, current interest in ice wedge studies in the Arctic is associated with the forecast of their transition to an inactive state and degradation as a response to climate warming. [14][15][16][17] Winter paleotemperature reconstructions for the Russian and North American Arctic have shown a long-term winter warming trend throughout the Holocene in some regions (e.g., Dm.…”