by A. May, Feb 13, 2026 in WUWT

Glacier length changes through time, they advance when the local climate around them is colder and retreat when it is warmer (Bray, 1968). Over century and greater time scales glacier length is considered a highly reliable indicator of both regional and worldwide warming trends according to Olga Solomina, Johannes Oerlemans, and the IPCC (Solomina et al., 2008), (Oerlemans, 2005) & (IPCC, 2001, pp. 127-130). While studying glacier lengths can illuminate long-term warming or cooling trends in glaciated areas is true, the idea that they can reveal hemisphere-wide or global climatic trends is somewhat speculative.

Advancing and retreating glaciers leave evidence of their fluctuations in length in glacial till deposits called moraines. Glacier moraines are easily identified and are distinct from other sediments and sedimentary rocks because they contain angular boulders, and they are unsorted and unstratified. Olga Solomina and colleagues in a 2015 review article, note:

“Studies of Holocene glacial geomorphic and sedimentological records provide the most direct means of determining the extent and timing of glacier oscillations. Until recently it has been difficult to define the ages of moraines in many regions because of the lack of appropriate dating techniques. Radiocarbon has been the most widely used and in some cases optically stimulated luminescence (OSL) dating has been implemented, but in most cases these can only be utilized to provide maximum and/or minimum ages on moraines by dating organic-rich deposits that are buried beneath moraines/tills, beyond the glacial limit (maximum ages), on top of moraines, or within the glacial limit (minimum ages). The development of terrestrial cosmogenic nuclide (TCN) dating, however, has provided a direct method of dating moraines and has led to a plethora of studies that are shedding new light on the nature of Holocene glacier fluctuations.” (Solomina et al., 2015)”

Dating Glacial Advances

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