A Millennial Scale Tree-Ring Based Summer Temperature Reconstruction for Northern Mongolia (931-2005 C.E.)

Warming over Mongolia and adjacent Central Asia has been unusually rapid over the past few decades, with surface temperature anomalies higher than for much of the globe. With few meteorological records available in this remote region prior to the 1950s, longer, paleoclimatic time series must be used to understand annual-centennial climate variability, potential forcing mechanisms (e.g. volcanism, increasing greenhouse gases) and the significance of such major features of the past millennium as the Medieval Climate Anomaly and Little Ice Age. In this study we use an unusually extensive collection of living and subfossil wood samples from temperature-sensitive larch trees to produce the first millennial-length, well-calibrated and verified reconstruction of summer temperatures for Mongolia and vicinity. The reconstruction shows a very cold mid-900s, rapid and sustained warming during the MCA, cooling during the LIA epoch LIA (1350-1850), and warming during the 20th century. There is very rapid tree growth found in 2004-2005, which may result from very warm temperatures and melting permafrost. The recent warming exceeds that of the MCA. Extreme cooling in several years is attributed to several major volcanic eruptions over the past millennium.