July 12, 2011
Nannbreen is a 5 km long land terminating glacier in southwest Svalbard. The glacier is just north of Hornsund. During the course of the 20th century Nannbreen retreated from its Little Ice Age moraine complex forming a new proglacial lake. The glacier ends at an elevation of 150 meters descending from 600 meters, the snowline in several Landsat images from the last decade has been 400-450 meters. By 2000 (first image below)the glacier had retreated 750 meters from the moraine complex and the glacier ended in a lake, that was over 500 meters long. In 2010 (second image below) the glacier had retreated out of the lake, 250 meters of retreat in 10 years, 1000 meters of retreat in the last century. Certainly the 21st century retreat rate is far above the average 20th century retreat rate. Most of the large glaciers in Svalbard are tidewater calving glaciers, such as the nearby Hansbreen, which retreated 400 meters from 2000-2005. Svalbard glaciers have been losing considerable volume, indicative of negative mass balance and glacier retreat. Nuth et al (2010) concluded that over the past 40 years for Svalbard ice loss is 9.71 ± 0.55 cubic kilometers/year. This is an average thinning of 0.36 meters/year for an annual contribution to global sea level rise of 0.026 mm yr.