Glaciers and ice caps peripheral to the main Greenland Ice Sheet contribute markedly to sea-level rise 1-3 . Their changes and variability, however, have been difficult to quantify on multi-decadal timescales due to an absence of long-term data 4 . Here, using historical aerial surveys, expedition photographs, spy satellite imagery and new remote-sensing products, we map glacier length fluctuations of approximately 350 peripheral glaciers and ice caps in East and West Greenland since 1890. Peripheral glaciers are found to have recently undergone a widespread and significant retreat at rates of 12.2 m per year and 16.6 m per year in East and West Greenland, respectively; these changes are exceeded in severity only by the early twentieth century post-Little-Ice-Age retreat. Regional changes in ice volume, as reflected by glacier length, are further shown to be related to changes in precipitation associated with the North Atlantic Oscillation (NAO), with a distinct east-west asymmetry; positive phases of the NAO increase accumulation, and thereby glacier growth, in the eastern periphery, whereas opposite effects are observed in the western periphery. Thus, with projected trends towards positive NAO in the future 5,6, eastern peripheral glaciers may remain relatively stable, while western peripheral glaciers will continue to diminish.
- Programområde 5: Natur og klima