NOAA/WDS Paleoclimatology - Greenland 11,500 Year Temperature Reconstruction

STUDY NOTES: Volcanic forcing time series and Greenland temperature reconstruction, plus modeled Northern Hemisphere average temperature, for the past 11,500 years. Reconstructions are based on argon and nitrogen isotopes from trapped air in the GISP2 Greenland ice core. Greenland Temperature file updated 12/02/2017 - a preliminary version had inadvertently been contributed. Data here are those plotted in Fig.2a. d15N file (Kobashi et al. 2008) also added 12/02/2017.
ABSTRACT SUPPLIED BY ORIGINATOR: Solar variability has been hypothesized to be a major driver of North Atlantic millennial-scale climate variations through the Holocene along with orbitally induced insolation change. However, another important climate driver, volcanic forcing has generally been underestimated prior to the past 2,500 years partly owing to the lack of proper proxy temperature records. Here, we reconstruct seasonally unbiased and physically constrained Greenland Summit temperatures over the Holocene using argon and nitrogen isotopes within trapped air in a Greenland ice core (GISP2). We show that a series of volcanic eruptions through the Holocene played an important role in driving centennial to millennial-scale temperature changes in Greenland. The reconstructed Greenland temperature exhibits significant millennial correlations with K+ and Na+ ions in the GISP2 ice core (proxies for atmospheric circulation patterns), and d18O of Oman and Chinese Dongge cave stalagmites (proxies for monsoon activity), indicating that the reconstructed temperature contains hemispheric signals. Climate model simulations forced with the volcanic forcing further suggest that a series of large volcanic eruptions induced hemispheric-wide centennial to millennial-scale variability through ocean/sea-ice feedbacks. Therefore, we conclude that volcanic activity played a critical role in driving centennial to millennial-scale Holocene temperature variability in Greenland and likely beyond.