ABSTRACT

Extreme summer temperatures are increasingly common across the Northern Hemisphere and inflict severe socioeconomic and biological consequences. In summer 2021, the Pacific Northwest region of North America (PNW) experienced a 2-week-long extreme heatwave, which contributed to record-breaking summer temperatures. Here, we use tree-ring records to show that summer temperatures in 2021, as well as the rate of summertime warming during the last several decades, are unprecedented within the context of the last millennium for the PNW. In the absence of committed efforts to curtail anthropogenic emissions below intermediate levels (SSP2-4.5), climate model projections indicate a rapidly increasing risk of the PNW regularly experiencing 2021-like extreme summer temperatures, with a 50% chance of yearly occurrence by 2050. The 2021 summer temperatures experienced across the PNW provide a benchmark and impetus for communities in historically temperate climates to account for extreme heat-related impacts in climate change adaptation strategies.

About the Speaker:

Dr. Karen King is an assistant professor in the Department of Geography and Sustainability and the director of the Tree Ring Lab at the University of Tennessee Knoxville. She holds a BS in Ethnobotany, an MS in Applied Ecology and Conservation Biology, a PhD in Geography, and she recently completed a postdoctoral research fellowship at Columbia University's Lamont Doherty Earth Observatory. Karen is a broadly trained physical geographer, specializing in paleoclimatology, biogeography, and dendrochronology (tree-rings). Her research interests generally focus on Quaternary landscape dynamics and paleoenvironmental reconstruction from intra-annual to multi-century time scales. She uses tree-ring records to investigate landscape‐scale dynamics and to integrate present‐day climatic and ecological processes with those that functioned in the past and those that are likely to become altered in the near‐future. Outside of research, Karen also has years of experience in wildland firefighting and prescribed fire management.