Fire history of SW Greenland: Characterizing long term climate-fire relationships using lake sediments

Climate warming occurs at an accelerated rate in the Arctic. One impact of increasingly warm and dry conditions in parts of the Arctic are fires in areas that have burned rarely in the past. In 2017, SW Greenland experienced record-setting fires, raising local concern, generating news stories around the world and leading to speculation that a warm, dry summer had led to unusual burning. Such fires may play an important role in global climate feedbacks, increasing soil temperatures for years after they occur and releasing carbon from previously frozen soils to the atmosphere. Soot from burning may accelerate the thaw of the Greenland Ice Sheet by darkening its surface. Despite these implications, it is unknown whether these recent fires are truly novel, because observational records of remote Greenland fires date back only 15 years. It is also unknown whether tundra fires are linked to dry, warm climate conditions in Greenland, especially given the role that human ignition sources also played in some recent fires. In this study, we will use charcoal from lake sediments in areas that burned in 2017 to assess fire history over thousands of years. In addition, we will reconstruct past temperature and moisture conditions using isotopes from insect remains and vegetation change using plant fossils, allowing us to examine linkages between climate, vegetation change, and any past fire activity. This research will produce the first long-term insight into Greenland fire regimes, and provide key baseline estimates by which to assess both recent and future burning.