Abstract:
Recent studies have shown significant warming of inland water bodies throughout the world. To better understand the patterns, mechanisms, and ecological implications of global lake warming, an initiative known as the "Global Lake Temperature Collaboration" (GLTC) was started in 2010, with the objective of compiling and analyzing lake temperature data from numerous in situ and satellite-based records dating back at least 20-30 years. The GLTC project has now assembled data from over 300 lakes, with some in situ records extending back more than 100 years. Here, we present an analysis of the long-term warming trends, interdecadal variability, and a direct comparison between in situ and remotely sensed summer lake surface temperatures from 1895-2009. The results show consistent trends of lake surface warming across most but not all sites. A few "hotspots" of warming are identified around the globe, including the Laurentian Great Lakes. Some lakes with especially long records show accelerated warming in the most recent two to three decades. Almost half of the world's lake surfaces are warming at rates in excess of 0.5 °C per decade during the period 1985-2009, and a few even exceed 1.0 °C per decade.