Understanding glacier and climate variations since pre-Industrial times is crucial for evaluating the present-day glacier response to climate change. Here, we focus on twelve small glaciers (≤2.0 km2) on both the northern and southern slopes of the Greater Caucasus to assess post-Little Ice Age glacier–climate fluctuations in this region. We reconstructed the Little Ice Age glacier extent using a manual detection method based on moraines. More recent glacier fluctuations were reconstructed using historical topographical maps and satellite imagery. Digital elevation models were used to estimate the topographic characteristics of glaciers. We also used the accumulation area ratio (AAR) method and a regional temperature lapse rate to reconstruct glacier snowlines and corresponding temperatures since the 1820s. The results show that all selected glaciers have experienced area loss, terminus retreat, and equilibrium line altitude (ELA) uplift over the last 200 years. The total area of the glaciers has decreased from 19.1 ± 0.9 km2 in the 1820s to 9.7 ± 0.2 km2 in 2020, representing a −49.2% loss, with an average annual reduction of −0.25%. The most dramatic reduction occurred between the 1960s and 2020, when the glacier area shrank by −35.5% or −0.59% yr−1. The average terminus retreat for all selected glaciers was −1278 m (−6.4 m/yr−1) during the last 200 years, while the average retreat over the past 60 years was −576 m (−9.6 m/yr−1). AAR-based (0.6 ± 0.05) ELA reconstructions from all twelve glaciers suggest that the average ELA in the 1820s was about 180 m lower (3245 ± 50 m a.s.l.) than today (3425 ± 50 m a.s.l.), corresponding to surface air temperatures <1.1 ± 0.3 °C than today (2001–2020). The largest warming occurred between the 1960s and today, when snowlines rose by 105 m and air temperatures increased by <0.6 ± 0.3 °C. This study represents a first attempt at using glacier evidence to estimate climate changes in the Caucasus region since the Little Ice Age, and it can be used as a baseline for future studies.
In the midlatitudes of the planet, we are facing the imminent disappearance of one of our best high-resolution (pre)historic climate and anthropogenic pollution archives, namely the loss of glacial ice, through accelerated global warming. To capture these records and interpret these vanishing archives, it is imperative that we extract ice-cores from midlatitude regions where glaciers still survive and analyse them within frameworks of inter-disciplinary research. In this paper, we focus on Georgia, part of the Greater Caucasus. Results of ice-core analyses from the region have never, to date, been integrated with its other abundant palaeo-environmental, archaeological and historical sources. We review the results of international projects on palaeo-environmental/geoarchaeological sediment archives, the archaeology of metal economies and preliminary ice-core data in Georgia. Collectively, we show that the different strands need to be integrated to fully explore relationships between climate/landscape change and human societal transformations. We then introduce an inclusive interdisciplinary framework for ongoing research on these themes, with an ultimate future goal of using data from the past to inform societal resilience strategies in the present.
We report interlaboratory comparisons of a methodology to measure and calculate concentrations of impurities in ice core samples using the Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) system developed at the W. M. Keck Laser Ice Facility at the Climate Change Institute, University of Maine (UMaine). Here, we will summarize results of measured artificial samples with known levels of Ca, Al, Fe, Mg, Na, Cu, Pb. We adapted a method for LA-ICP-MS analysis of the frozen standard that was developed in the laboratory at Ca’ Foscari University of Venice, and we tested its applicability to the UMaine system. This work will help to measure and interpret very old and highly compressed ice core records from the Allan Hills Blue Ice Area, Antarctica, sampled with different analytical tools.