Contemporary glacigenic inputs to the dust cycle

Abstract

The importance of glacigenic dust in the Earth's system during glacial periods is widely acknowledged. Under contemporary conditions, the world's largest dust sources are in low‐lying, hot, arid regions and this is where most aeolian research is focused. However the processes of dust production and emissions are still operating in cold climate regions, particularly in proglacial areas. This paper assesses current understanding of the relationship between glacierised landscapes and dust emissions and inputs to the global dust cycle. It focuses on how elements in the glacial and aeolian geomorphic sub‐systems interact to determine the magnitude, frequency and timing of aeolian dust emissions, and on feedback mechanisms between the systems. Where they have been measured, dust emission intensity and deposition rates in glacierised catchments are very high, in some cases far exceeding those in lower latitudes, however, few studies span long time scales. The impact of future glacier retreat on the balance between sediment supply, availability and aeolian transport capacity and implications for glacigenic dust emissions is also considered. This balance depends on relative spatial and temporal changes in meltwater suspended sediment concentration and wind strengths, which promote dust emissions, and patterns and rates of soil development and vegetation succession on recently‐deglaciated terrain which protect sediments from deflation. Retreat of the Antarctic ice sheet could mean that in future glacigenic contributions to the dust cycle exceed those of non‐glacigenic sources in the southern hemisphere. Copyright © 2012 John Wiley & Sons, Ltd.

Long-term variability of dust events in Iceland (1949–2011)

“…Such a high frequency shows that active volcanic and glacial deserts, such as Iceland, differ from the crustal deserts; this is due to the permanent input of volcanic materials, frequent re-suspension of these materials, and the climatic effects of glaciers causing strong down-slope winds. A high number of the dust observations presented here reflect previous studies showing high dust deposition rates in Iceland (Arnalds, 2010;Prospero et al, 2012;Thorarinsdottir and Arnalds, 2012;Bullard, 2013;Arnalds et al, 2013;Arnalds et al, 2014) and places the country among the most important dust producing areas of the world. Iceland is likely to be the largest and most active high-latitude cold dust source.…”

“…Dust events in Arctic and subarctic regions have been observed in Alaska (Nickling, 1978;Crusius et al, 2011), Greenland (Bullard, 2013), Svalbard (Dornbrack et al, 2010) and Iceland (Arnalds, 2010;Prospero et al, 2012;Thorarinsdottir and Arnalds, 2012). Arctic coastal zones are considered the windiest regions on Earth (Eldridge, 1980).…”

“…The highest dust emissions in Arctic regions occur in summer and early autumn (Nickling, 1978;Bullard, 2013;Dagsson-Waldhauserova et al, 2013). Dust concentrations in subarctic regions peak in spring (April-June, Prospero et al, 2012).…”

“…Cold climate regions are represented by long-term dust frequency in Northeast (NE) Iceland (Dagsson-Waldhauserova et al, 2013). Dust emission intensity and deposition rates in active glacial environments have been found to be very high, in some cases far exceeding those in lower latitudes (Bullard, 2013). Ganopolski et al (2009) calculated glaciogenic dust deposition > 50 g m −2 yr −1 at the last glacial maximum, with the highest rates over northwestern Europe.…”

“…Ganopolski et al (2009) calculated glaciogenic dust deposition > 50 g m −2 yr −1 at the last glacial maximum, with the highest rates over northwestern Europe. Recently, the highest deposition rates of glaciogenic dust (> 500 g m −2 yr −1 ) are reported from Iceland (Arnalds, 2010, see also Bullard, 2013).…”