Kronebreen is calving

Picture of the year:

Thunder rolls under the clear Arctic sky. Eagerly your eyes scan the face of the glacier. There! A chunk of blue ice the size of a railroad car tips with impossibly slow grandeur and plunges into the water. Waves churn towards you, threatening to swamp your boat. Watching a glacier calve is thrilling: beauty and peril combined.

This is Kronebreen. When explorers first saw it in the late 1800s, it extended 10 km further into Kongsfjorden. By the end of World War II, the front had retreated about 6 km. From the late 1980s to about 2000, it lay another couple kilometres farther east over a rise in the seabed, which kept the glacier in a stable position. But ultimately the delicate balance between ice flow toward the front and ice loss through calving shifted and the front retreated into deeper water. With more water eating away at the base of the glacier, calving increased, and since 2011 the glacier front has retreated by over 2 km.

Is this because of global warming? Clearly, several factors are at play. Subglacial topography has nothing to do with climate. But Kronebreen’s mass balance is also affected by climate factors like the amount and type of precipitation, radiation, summertime melt and water temperatures in Kongsfjorden. Those temperatures are influenced by the West Spitsbergen current, which has been warming for the past 40 years.

So no, global warming isn’t the only explanation for the spectacular calving in eastern Kongsfjorden. But it clearly contributes.

Photo: Geir Wing Gabrielsen, Norwegian Polar Institute. Text: Janet Holmén