An analysis of aerial photographs suggests that ice loss in northwestern Greenland results from discrete events driven by changes in ocean and atmospheric temperature.

Kurt Kjær at the University of Copenhagen's Natural History Museum and his team used photographs dating back to 1985 to create a three-dimensional model of ice loss and gain. Rather than exhibiting a uniform melt rate, the model revealed that ice loss peaked in two periods: 1985–93 and 2005–10. The researchers linked this ice loss to warmer oceans and higher summer air temperatures. Ice-sheet models must account for such variability if they are to produce reliable forecasts.

Credit: J. BALOG/AURORA/GETTY

Science 337, 569–573 (2012)