Extremes, Teleconnections, and Trends in Growing Season Precipitation over the Corn Belt, 1182–2023 CE

Abstract Tree-ring chronologies were used to reconstruct growing-season precipitation for the North American Corn Belt from 1182–2023 CE. The reconstruction explains close to 60% of the variance in instrumental May–July precipitation totals (1901–2014) and reproduces the teleconnections with circulation and surface climate variables detected in the instrumental precipitation data, substantiating the skill of the reconstruction and indicating episodic co-occurrence of drought between major crop production regions of the central United States and Eurasia. The episode with five consecutive years of deficit May through July precipitation totals in the Corn Belt from 1930–1934 during the Dust Bowl drought was exceeded by several uninterrupted droughts reconstructed during the pre-instrumental period. The early 17 th century drought (1627–1639) was the most severe, sustained, and unbroken drought in the reconstruction for at least 600-years and has no analog in the modern instrumental observations. This drought coincided with decadal dryness in China and eastern Europe and provides a paleoclimatic example of simultaneous megadrought in major breadbasket regions of Eurasia and North America. The decade of wetness during the early 21 st century in the instrumental observations appears to have been unmatched for 700-years and may have been enhanced by increased humidity and radiation changes associated with the dramatic intensification of agriculture in the Corn Belt.