Collaborative Research: A North Pacific ice core record of summer climate and wildfire history during the last 1500 years

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This project intends to use the Mount Denali ice core archive to develop the most comprehensive suite of North Pacific fire and summer climate proxy records since about 2500 years before present. Wildfire is a key component of summer climate in the North Pacific where wildfires are projected to increase with continued summer warming. Studies that combine paleorecords of summer climate and wildfire are therefore critically needed, especially in the North Pacific region where fire recurrence rate and decadal-to-centennial scale climate fluctuations occur over longer time periods than are covered by direct observations. The goal of the proposed research is to improve our understanding of relationships between summertime climate and wildfire activity, focusing especially on the Medieval Climate Anomaly (MCA), when regional temperatures were perhaps as warm as the 20th century. Recent advances now permit the measurement of new fire-related (pyrogenic) compounds in ice cores, enabling the development of a robust fire record capable of rigorous comparison with regional paleoclimate reconstructions. The records of summer atmospheric circulation developed through this project will be regionally unique and fill a critical gap in the suite of North Pacific paleoclimate records. The ice core fire records will have synchronously dated temperature, precipitation and circulation time series. Our unique compilation of these ice core records, as well as other regional paleoproxy records will be the first effort at combining these datasets into a regional compilation of paleofire records in the North Pacific region. This compilation will facilitate the examination of fire activity during Medieval Climate Anomaly (MCA) conditions that are of comparable magnitude to present climate changes over socially relevant timescales (decades). We will analyze the archive Denali ice core for black carbon, which is derived from both biomass and fossil fuel combustion, and organic aromatic acids (e.g. vanillic acid) and monosaccharide anhydride (e.g. levoglucosan) which are produced solely from biomass burning. The Denali ice core chronology is already developed, and the archive ice is in hand, ensuring that our research plan can be accomplished. Fire record synthesis and calibration will incorporate instrumental fire databases, gridded burn area data, and HYSPLIT back-trajectory analyses over the instrumental era in order to test the sensitivity of fireclimate relationships over time. With this record we will address the following research questions: (1) How have North Pacific summer atmospheric circulation patterns varied over the last 1500 years? (2) How did North Pacific fire regime characteristics naturally respond to the warm summer conditions of the Medieval Climate Anomaly (MCA)? (3) Are there consistent relationships between North Pacific fire regime and climate?A focal point of our broader impacts is support for two young investigators who have specialized expertise in North Pacific ice cores and paleofire modeling, respectively. This project will also support one PhD student and several undergraduate students. We will continue our longstanding collaboration with Denali National Park to present and permanently display our major climate- and fire-related findings at the park visitor center in Talkeetna, Alaska. We are partnering with the Natural Sciences Education and Outreach Center at Colorado State University to develop STEM kits focused on the Denali ice core record for distribution to under-served K-12 students in Alaska and Maine. Prototypes of these kits have already been developed and tested with students, and we propose to significantly expand this program and increase its impact. Other activities include the participation of first-year women researchers in this project as part of the Dartmouth Women In Science Project (WISP) initiative, and through participation in the NSF-supported School of Ice, where faculty from historically black colleges and minority-serving institutions learn about ice cores and climate change.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.