Geophys. Res. Lett. http://doi.org/rvn (2014)

The extent of Arctic sea-ice cover during the summer melt season has declined sharply over the past decade or two. Ice-loss measurements show that the sea ice near the North Pole has, at least so far, not experienced substantial losses.

Credit: © AURORA PHOTOS / ALAMY

Don Perovich at the US Army Cold Regions Research and Engineering Laboratory and colleagues examined annual losses in sea ice between the North Pole and Greenland as a result of summer melt over the past 14 years, as measured by autonomous buoys tracking sea-ice mass balance. They found large variability in melt between years at both the bottom and top of the sea ice. Also, the ice remained over a metre thick at the end of each melt season. They suggest that the survival of sea ice in the region can be attributed to the lower solar radiation reaching the surface at these high latitudes, compared to the periphery of the sea ice cap.

Although the measurements show no definitive increase in sea-ice melt in the North Pole over the study period, the largest amounts of bottom melt have occurred in the past few years, an observation often associated with rapid sea-ice loss and indicative of a warming ocean.