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Multidecadal trends in the terminus position of outlet glaciers along the margin of the East Antarctic ice sheet reveal three epochal patterns of glacier retreat or advance consistent with a rapid and coherent response to air temperature and sea-ice trends. East Antarctic ice sensitive to climate variation It is widely known that glaciers in West Antarctica and Greenland have been discharging ice into the oceans in response to warming in recent years, and that sea levels have risen as a result. By contrast, we hear little about the much larger East Antarctic ice sheet, which has been viewed as being less vulnerable to climate change owing to its location in an extremely cold climate. Chris Stokes and colleagues have used satellite imagery to map a large sample of glaciers along the Pacific coast of East Antarctica and show that in fact, they are responding to decadal climate variability. In concert with climate, glaciers retreated in the 1970s and 1980s, advanced in the 1990s, and approximately split between advance and retreat since the 2000s. The authors conclude that parts of the world's largest ice sheet may be more responsive to external forcing than previously recognized. Observations of ocean-terminating outlet glaciers in Greenland and West Antarctica.sup.1,2,3,4,5,6 indicate that their contribution to sea level is accelerating as a result of increased velocity, thinning and retreat.sup.7,8,9,10,11. Thinning has also been reported along the margin of the much larger East Antarctic ice sheet.sup.1, but whether glaciers are advancing or retreating there is largely unknown, and there has been no attempt to place such changes in the context of localized mass loss.sup.7,9 or climatic or oceanic forcing. Here we present multidecadal trends in the terminus position of 175 ocean-terminating outlet glaciers along 5,400 kilometres of the margin of the East Antarctic ice sheet, and reveal widespread and synchronous changes. Despite large fluctuations between glaciers--linked to their size--three epochal patterns emerged: 63 per cent of glaciers retreated from 1974 to 1990, 72 per cent advanced from 1990 to 2000, and 58 per cent advanced from 2000 to 2010. These trends were most pronounced along the warmer western South Pacific coast, whereas glaciers along the cooler Ross Sea coast experienced no significant changes. We find that glacier change along the Pacific coast is consistent with a rapid and coherent response to air temperature and sea-ice trends, linked through the dominant mode of atmospheric variability (the Southern Annular Mode). We conclude that parts of the world's largest ice sheet may be more vulnerable to external forcing than recognized previously., Author(s): B. W. J. Miles [sup.1] , C. R. Stokes [sup.1] , A. Vieli [sup.1] [sup.2] , N. J. Cox [sup.1] Author Affiliations: (1) Department of Geography, Durham University, Science [...]

Small mountain glaciers are an important part of the cryosphere and tend to respond rapidly to climate warming. Historically, mapping very small glaciers (generally considered to be <0.5 km2) using satellite imagery has often been subjective due to the difficulty in differentiating them from perennial snowpatches. For this reason, most scientists implement minimum size-thresholds (typically 0.01–0.05 km2). Here, we compare the ability of different remote-sensing approaches to identify and map very small glaciers on imagery of varying spatial resolutions (30–0.25 m) and investigate how operator subjectivity influences the results. Based on this analysis, we support the use of a minimum size-threshold of 0.01 km2 for imagery with coarse to medium spatial resolution (30–10 m). However, when mapping on high-resolution imagery (<1 m) with minimal seasonal snow cover, glaciers <0.05 km2 and even <0.01 km2 are readily identifiable and using a minimum threshold may be inappropriate. For these cases, we develop a set of criteria to enable the identification of very small glaciers and classify them as certain , probable or possible. This should facilitate a more consistent approach to identifying and mapping very small glaciers on high-resolution imagery, helping to produce more comprehensive and accurate glacier inventories. [ABSTRACT FROM AUTHOR]

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