Enhanced ice sheet melting driven by volcanic eruptions during the last deglaciation

Francesco Muschitiello,Douglas W F Mair,James M Lea,Barbara Wohlfarth,Francesco S R Pausata

doi:10.1038/s41467-017-01273-1

Abstract

Volcanic eruptions can impact the mass balance of ice sheets through changes in climate and the radiative properties of the ice. Yet, empirical evidence highlighting the sensitivity of ancient ice sheets to volcanism is scarce. Here we present an exceptionally well-dated annual glacial varve chronology recording the melting history of the Fennoscandian Ice Sheet at the end of the last deglaciation (∼13,200–12,000 years ago). Our data indicate that abrupt ice melting events coincide with volcanogenic aerosol emissions recorded in Greenland ice cores. We suggest that enhanced ice sheet runoff is primarily associated with albedo effects due to deposition of ash sourced from high-latitude volcanic eruptions. Climate and snowpack mass-balance simulations show evidence for enhanced ice sheet runoff under volcanically forced conditions despite atmospheric cooling. The sensitivity of past ice sheets to volcanic ashfall highlights the need for an accurate coupling between atmosphere and ice sheet components in climate models.

Highlights

Greenland records of volcanism are sensitive to highlatitude eruptions as compared to tropical eruptions owing to the close proximity to the source region
High-latitude volcanic sulfate signatures are better represented in the ice than their tropical counterparts (Supplementary Fig. 8)
Icelandic volcanoes remain the dominant source of volcanogenic aerosols in Greenland ice cores due to their relative proximity and high eruptive frequency[37]

Summary

Introduction

Summary statistics of volcanically forced change in annual runoff model results (given in cm water equivalent, w.e.) and related standard deviations for a summer high-latitude volcanic eruption. The alpha value of the albedo refers to albedo of both snow and ice. The full simulation results are shown in Supplementary Fig. 4 high-latitude volcanic eruptions in historical time—the Laki eruption (Iceland, 8 June 1783)—to test the effect of high-latitude eruptions on radiative forcing and climate (Methods section).

Results

Conclusion