NOAA/WDS Paleoclimatology - King - Mount Washburn Update - PIEN - ITRDB WY075

Projected warming of global surface air temperatures will further exacerbate droughts, wildfires, and other agents of ecosystem stress. We use latewood blue intensity from high-elevation Picea engelmannii to reconstruct late-summer maximum air temperature for the Greater Yellowstone Ecoregion (GYE) spanning 770-2019 CE. Using a robust regression model (r2=0.60), the 1,250-year reconstruction reveals 2016 as the single-warmest year and the warming trend since ca. 2000 as the most intense. The Medieval Climate Anomaly contained the highest-ranking warm event (1050-1070 CE) and was characterized by substantial multi-decadal variability rather than a period of prolonged, homogeneous warming. We document regional expression of past warm and cool events, such as an anomalously warm period spanning the 15th-16th centuries, and the Maunder and Dalton minima of the Little Ice Age. Summer temperature variability across the GYE shows multi-centennial agreement with trends in solar irradiance, volcanic activity, snowpack, and other regional-to-hemispheric temperature records.