A University of Alaska Fairbanks-led research project has provided the first modern evidence of a landscape-level permafrost carbon feedback, in which thawing permafrost releases ancient carbon as climate-warming greenhouse gases.The study was published today in the journal Nature Geoscience.The project, led by UAF researcher Katey Walter Anthony, studied lakes in Alaska, Canada, Sweden and Siberia where permafrost thaw surrounding lakes led to lake shoreline expansion during the past 60 years. Using historical aerial photo analysis, soil and methane sampling, and radiocarbon dating, the project quantified for the first time the strength of the present-day permafrost carbon feedback to climate warming. Although a large permafrost carbon emission is expected to occur imminently, the results of this study show nearly no sign that it has begun.