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Abstract:
From paleoproxy reconstructions and climate model simulations of the Northern Hemisphere (NH) climate during the Common Era (CE), we know that strong volcanic eruptions have induced cold periods like the Little Ice Age (LIA) and the mid-6th century cooling. However, less is known about such cold periods during the Holocene. Here, we study the Max Planck Institute Earth System Model Holocene simulations (6000 BCE to 1850 CE). One of the runs is forced with orbital forcing, land cover, greenhouse gas concentrations, solar forcing, stratospheric ozone, and volcanic forcing. The other run includes only orbital forcing and greenhouse gas concentrations. We simulate a large number of extremely cold years in the all-forcing run, which is primarily explained by volcanic eruptions. Applying a 200-year filter reveals 11 long-lasting cold periods similar to the LIA during the mid to late-Holocene, occurring every once or twice per millennium. These long-lasting cold periods correspond to increased volcanic activity, where the clustering of volcanic eruptions leads to an integrated cooling effect through the slow ocean-sea ice response. Eight of the eleven multi-centennial cold periods in our simulation correspond to previously identified phases of glacier advances throughout the NH, as well as reduced ring widths in tree ring records from Northern Finland. Whereas previous studies used mostly local proxy reconstructions, we identify NH annual mean multi-centennial cold periods. Finding several more such cold periods highlights the importance of understanding volcanic-induced long-lasting cold periods and the impact they could have had on society in the past.
