Southeast Greenland glaciers that reach the ocean retreated faster in the past decade than in the 1930s, whereas the opposite is true for land-terminating glaciers, reports a study published online this week in Nature Geoscience. Air and ocean temperatures were similar during the two periods, indicating that the sensitivities of the different glacier types to warming have changed.
Anders Bjork and colleagues assembled historical aerial photographs taken in 1932-33 during a systematic survey of the southeastern Greenland coast, as well as air photos obtained by the US military during the Second World War and satellite images, to study changes in the southeastern Greenland margin over the past 80 years. They find that overall glacier retreat was as vigorous in the 1930s warming period as it has been in the 2000s. However, the response of different glacier types to warming varies.
In an accompanying News and Views article, Benjamin Smith writes that the research “indicates that the retreat [of Greenland glaciers] in the 2000s was a typical response of the ice sheet to warmer air and ocean temperatures”.