Since the first core drilled in a cave ice deposit in 1947, more than 141 m of ice
cores has been extracted from 20 cave ice deposits worldwide until 2021. Cave ice
drilling projects focused mainly in Central European caves, however, half of the cave
ice cores (3 out of 6) published in 2020 represent non-European localities predicts
that an increasing number of such projects are focusing on other geographical areas
hosting ice caves. Depending on the two types of ice encountered (firnified snow and
frozen water), local climatic conditions and cave geometry, cave ice cores have highly
variable length (between 1 and 25 m long), time span and continuity of the record
covered (from a few years up to several thousands of year). The longest cave ice core
in terms of both core length (~25 m) and continuous time span (~10 kyr) comes from
Scărișoara Ice Cave (Romania), with several others (in Spain, Slovakia, Austria, Romania,
the USA) reaching back in time towards (and beyond) the mid-Holocene. Major challenges
in cave ice core science are posed by 1) presence of englacial rocky and woody debris,
2) complex stratigraphy of the ice deposits (often disturbed due to ice flow in a
restricted space), 3) problematic chronology and 4) complex mechanisms of climate-proxy
information transfer. Regardless, cave ice deposits offered over the past decade several
unique records of Holocene climate and environmental change as well as of past microbial
and fungal diversity. Because ice caves are located at much lower altitudes and latitudes
than polar and mountain glaciers, they face the double threat of both increasing temperatures
and precipitation amounts, several possible milennial old deposits being lost over
the past few years. An ongoing race to salvage the paleoclimatic information these
ice deposits holds is thwarted by climatic, financial and knowledge risks.
