Exceptional retreat of Novaya Zemlya's marine-terminating outlet glaciers between 2000 and 2013

J Rachel Carr,Tom Holt,Heather Bell,Rebecca Killick

doi:10.5194/tc-11-2149-2017

Abstract

Abstract. Novaya Zemlya (NVZ) has experienced rapid ice loss and accelerated marine-terminating glacier retreat during the past 2 decades. However, it is unknown whether this retreat is exceptional longer term and/or whether it has persisted since 2010. Investigating this is vital, as dynamic thinning may contribute substantially to ice loss from NVZ, but is not currently included in sea level rise predictions. Here, we use remotely sensed data to assess controls on NVZ glacier retreat between 1973/76 and 2015. Glaciers that terminate into lakes or the ocean receded 3.5 times faster than those that terminate on land. Between 2000 and 2013, retreat rates were significantly higher on marine-terminating outlet glaciers than during the previous 27 years, and we observe widespread slowdown in retreat, and even advance, between 2013 and 2015. There were some common patterns in the timing of glacier retreat, but the magnitude varied between individual glaciers. Rapid retreat between 2000 and 2013 corresponds to a period of significantly warmer air temperatures and reduced sea ice concentrations, and to changes in the North Atlantic Oscillation (NAO) and Atlantic Multidecadal Oscillation (AMO). We need to assess the impact of this accelerated retreat on dynamic ice losses from NVZ to accurately quantify its future sea level rise contribution.

Highlights

Glaciers and ice caps are the main cryospheric source of global sea level rise and contributed approximately −215 ± 26 Gt yr−1 between 2003 and 2009 (Gardner et al, 2013)
Results demonstrated that total retreat rates (1986–2015) were significantly higher on lake- and marineterminating glaciers than those terminating on land, at a very high confidence interval (< 0.001) (Fig. 2)
Retreat rates were 3.5 times higher on glaciers terminating in water than those ending on land (−13.8 m a−1) (Fig. 2)

Summary

Introduction

Glaciers and ice caps are the main cryospheric source of global sea level rise and contributed approximately −215 ± 26 Gt yr−1 between 2003 and 2009 (Gardner et al, 2013). Outside of the Greenland Ice Sheet, the Russian high Arctic (RHA) accounts for approximately 20 % of Arctic glacier ice (Dowdeswell and Williams, 1997; Radicet al., 2014) and is, a major ice reservoir. It comprises three main archipelagos: Novaya Zemlya (NVZ; glacier area = 21 200 km2), Severnaya Zemlya (16 700 km2), and Franz Josef Land (12 700 km2) (Moholdt et al, 2012).

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Discussion

Conclusion