Nitrogen and Argon Isotope Data from GISP2 Ice Core

Future Greenland temperature evolution will affect melting of the ice sheet and associated global sea-level change.
Therefore, understanding Greenland temperature variability and its relation to global trends is critical. Here, we
reconstruct the last 1,000 years of central Greenland surface temperature from isotopes of N2 and Ar in air bubbles
in an ice core. This technique provides constraints on decadal to centennial temperature fluctuations. We found that
northern hemisphere temperature and Greenland temperature changed synchronously at periods of ~20 years and 40-100 years.
This quasi-periodic multi-decadal temperature fluctuation persisted throughout the last millennium, and is likely to
continue into the future.