资源环境科技发展态势分析平台

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 re‐gression 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 charac‐ terized by substantial multi‐decadal variability rather than a period of prolonged, ho‐ mogeneous warming. We document regional expression of past warm and cool events, such as an anomalously warm period spanning the 15^th 16^th centuries, and the Maun‐ der and Dalton minima of the Little Ice Age. Summer temperature variability across the GYE shows multi‐centennial agreement with trends in solar irradiance, volcanic activ‐ ity, snowpack, and other regional‐to‐hemispheric temperature records.