Acceleration of snow melt in an Antarctic Peninsula ice core during the twentieth century

• Main Authors: Nerilie J. Abram, Robert Mulvaney, Eric W. Wolff, Jack Triest, Luke D. Trusel, Françoise Vimeux, Louise Fleet, Carol Arrowsmith
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2013
• Subjects: Antarctic; Antarctic Peninsula; Ross Island; The Antarctic; Antarc*; ice core; Ice Sheet; Ice Shelves; James Ross Island
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.473.4817; http://xa.yimg.com/kq/groups/18383638/462790565/name/ngeo1787.pdf

Over the past 50 years, warming of the Antarctic Peninsula has been accompanied by accelerating glacier mass loss and the retreat and collapse of ice shelves. A key driver of ice loss is summer melting; however, it is not usually possible to specifically reconstruct the summer conditions that are critical for determining ice melt in Antarctic. Here we reconstruct changes in ice-melt intensity and mean temperature on the northern Antarctic Peninsula since AD 1000 based on the identification of visible melt layers in the James Ross Island ice core and local mean annual temperature estimates from the deuterium content of the ice. During the past millennium, the coolest conditions and lowest melt occurred from about AD 1410 to 1460, when mean temperature was 1.6 ◦C lower than that of 1981–2000. Since the late 1400s, there has been a nearly tenfold increase in melt intensity from 0.5 to 4.9%. The warming has occurred in progressive phases since about AD 1460, but intensification of melt is nonlinear, and has largely occurred since the mid-twentieth century. Summer melting is now at a level that is unprecedented over the past 1,000 years. We conclude that ice on the Antarctic Peninsula is now particularly susceptible to rapid increases in melting and loss in response to relatively small increases in mean temperature. Over the past decade, satellite monitoring has revealed thatmass loss from the margins of the Antarctic and Greenlandice sheets is more pervasive than previously realized and represents a significant source of sea-level rise1. A key driver of accelerated glacier outflow on these ice-sheet margins seems to be thinning and collapse of ice shelves. In some regions, such as the