Pre‐Industrial (1750–1850 CE) Cold Season Warmth in Northeastern China

Abstract

Abstract Contrary to global warming projections, northern mid‐latitude continents have suffered from an increased frequency of unusually cold winters during the last few decades. However, a lack of longer‐term cold‐season temperature records from mid‐latitudes hampers our understanding of the forcing mechanisms of this temperature variability. Here we report a Group 1 alkenone‐based high‐resolution record of cold‐season temperatures extending to the pre‐industrial era (since 1700 CE) from Lake Luming in northeastern China. By comparing with the instrumental and historical records in the region, we verify the high efficacy of Group 1 alkenones as recorders of cold‐season temperature variability. Our record shows pre‐industrial warmth between 1750 and 1850 CE relative to anthropogenic industrial period (since 1850 CE), which is largely driven by variability of the Arctic Oscillation, with a negligible contribution from anthropogenic greenhouse‐gas forcing. Our results highlight the importance of internal atmospheric circulation in driving cold‐season temperatures in northeastern China.