Glacier Surges Past and Present: Theory, Current Distribution and the Landform Record

The oft-quoted statistic that 1% of the world’s glaciers are surge-type may suggest that surging is a rare, anomalous phenomenon. Among some populations of glaciers, however, surge-type glaciers are in the majority. For example, for glaciers over 16 km in length in Svalbard and Iceland over half have recorded surges. Surge-type glaciers are widespread in a broad arc stretching from Alaska to Novaya Zemlya (the Arctic Ring) and in many parts of High Mountain Asia. This distribution is defined by ranges of temperature and precipitation within which many glaciers cannot achieve stable steady states, as predicted by Enthalpy Balance Theory. 

Climatic controls on surging behaviour imply that the distribution of surge-type glaciers will shift in response to changes in temperature and/or precipitation. For example, the Arctic Ring may have been located south of its current position during some colder periods of the Quaternary. This was likely the case for Younger Dryas glaciers in Scotland. Reconstructions of palaeotemperature and palaeoprecipitation indicate that the Highlands and Islands of Scotland fell within the optimal climatic envelope for surging during the Younger Dryas. Examination of the landform record supports the conjecture that surge-type glaciers were widespread, including many outlet glaciers of the West Highland Icefield and smaller icecaps on the islands. 

Recognition of palaeosurges is important, because glacier reconstructions are commonly used as climatic proxies based on the assumption that glacier geometries represent stable steady states. Landsystem models are useful in this regard, provided they are applied flexibly with due consideration for local conditions and preservation biases. Systematic use of landsystem models and other tools may reveal other former clusters of surge-type glaciers in mid-latitude mountain regions.