Glaciers in the High Arctic and recent environmental change

Abstract

High Arctic climate change over the last few hundred years includes the relatively cool Little Ice Age (LIA), followed by warming over the last hundred years or so. Meteorological data from the Eurasian High Arctic (Svalbard, Franz Josef Land, Severnaya Zemlya) and Canadian High Arctic islands are scarce before the mid-20th century, but longer records from Svalbard and Greenland show warming from about 1910-1920. Logs of Royal Navy ships in the Canadian Northwest Passage in the 1850s indicate temperatures cooler by 1-2.5 °C during the LIA. Other evidence of recent trends in High Arctic temperatures and precipitation is derived from ice cores, which show cooler temperatures (by 2-3 °C) for several hundred years before 1900, with high interdecadal variability. The proportion of melt layers in ice cores has also risen over the last 70-130 years, indicating warming. There is widespread geological evidence of glacier retreat in the High Arctic since about the turn of the century linked to the end of the LIA. An exception is the rapid advance of some surge-type ice masses. Mass balance measurements on ice caps in Arctic Canada, Svalbard and Severnaya Zemlya since 1950 show either negative or near-zero net balances, suggesting glacier response to recent climate warming. Glacier-climate links are modelled using an energy balance approach to predict glacier response to possible future climate warming, and cooler LIA temperatures. For Spitsbergen glaciers, a negative shift in mass balance of about 0.5 m a -1 is predicted for a 1 °C warming. A cooling of about 0.6 °C, or a 23% precipitation increase, would produce an approximately zero net mass balance. A ‘greenhouse-induced’ warming of 1 °C in the High Arctic is predicted to produce a global sea-level rise of 0.063 mm a -1 from ice cap melting.

Circum-Arctic Changes in the Flow of Glaciers and Ice Caps from Satellite SAR Data between the 1990s and 2017

“…Elevated areas can experience considerably higher precipitation. Mean annual temperatures in Severnaya Zemlya are about −16 • C, compared with about −12 • C in Franz Josef Land and −9 • C in Novaya Zemlya [43]. Severnaya Zemlya is quite dry, with average annual precipitation at the coastal stations between 220 and 270 mm and an increase in precipitation towards the summits of the major ice caps [21].…”

“…Even during summer the angle of the sun ray spreads the limited radiated energy over a large area. Further cooling is caused by the high amount of cloudiness [43]. Average annual precipitation at the coastal stations of Franz Josef Land is between 100 and 150 mm, with the wettest months being from July through September [44].…”

Form and flow of the Academy of Sciences Ice Cap, Severnaya Zemlya, Russian High Arctic

“…Mean annual temperatures in Severnaya Zemlya are about À16°C, compared with about À12°C in Franz Josef Land and À9°C in Novaya Zemlya (Figure 1) [Dowdeswell, 1995]. Precipitation increases from $0.25 to 0.45 m yr À1 (water equivalent) between sea level and the summits of the major ice caps [Bryazgin and Yunak, 1988].…”

“…The Academy of Sciences Ice Cap in Severnaya Zemlya provides a particularly suitable site for deep drilling because (1) it is in the driest part of the glacierized Eurasian sector [Dowdeswell, 1995] thus yielding a particularly long record; (2) it is in the coldest area, and its physical and chemical stratigraphy is therefore likely to be affected less by meltingrefreezing effects, including fractionation and percolation, than other Eurasian Arctic ice cores [e.g., Koerner, 1997]; and (c) its ice thickness is among the deepest in the archipelago.…”

“…The glacier ice on these Arctic islands covers an area of $ 92,000 km 2 , which is approaching 20% of the ice outside the Antarctic and Greenland ice sheets [ Dowdeswell , 1995]. There is a steep climatic gradient across the Eurasian High Arctic, from relatively warmer and more moist conditions on Svalbard in the west, where there is a strong northward transfer of heat in ocean currents and storm tracks up the Norwegian and Greenland Seas, to progressively colder and dri er con di ti on s fa rt he r ea s t. Th e 18 ,3 00 km 2 of ice ca ps on Severnaya Zemlya represent the easternmost ice masses of any significant size on this environmental gradient across the Eurasian Arctic which is, in turn, predicted by general circulation models to be a region of enhanced future warming [e.g., Cattle and Crossley, 1995].…”