Heterogeneous changes in the surface area of lakes in the Kangerlussuaq area of southwestern Greenland between 1995 and 2017

Abstract

Global climate change has increased temperatures and precipitation in the Arctic throughout the past thirty years. Lakes across the Arctic have demonstrated spatially and temporally variable trends in size and number because of these climate changes. Modifications in the hydrological budget and surface hydrology of Arctic regions have important implications for aquatic ecosystems and biogeochemical cycles. Since 1960 the ice-free region of southwestern Greenland (between Sisimiut, Kangerlussuaq, and the ice margin) has experienced temperature increases, while precipitation has risen at the coast at Sisimiut and has fallen inland at Kangerlussuaq. However, it remains unknown whether the lakes in this region have responded to these temperature and precipitation changes. Therefore, the surface area of 186 lakes was calculated from Landsat imagery for 1995, 2002, 2015, 2016, and 2017 to establish whether lakes in this region have changed in size during a twenty-two-year period. Lake surface area decreased by 855,449 m2 between 1995 and 2017. The greatest lake surface area changes occurred between 2002 and 2015, with large variations also between 2015 and 2016. Lakes close to Kangerlussuaq (area 1) demonstrated the greatest loss in lake surface area (−1.40 km2). It is proposed that this trend reflects high evaporation totals as a result of increasing temperatures and longer ice-free periods in this area. Lakes close to Sisimiut at the coast (area 2) exhibit a net increase in lake surface area, which could reflect the increase in precipitation experienced in this area during the study period. However, not all lakes in the study areas responded in a uniform manner. These heterogeneous changes in lake surface area may reflect how changes in regional climate are interacting with catchment geomorphology, and highlight the importance of individual catchment and lake characteristics in determining lake response to climatic change in this region.