Department of Earth Sciences Associate Professor Julie Fosdick worked on a new study to better understand the history of the Greenland ice sheet. The study, published in Science, looked at soil found at the bottom of an ice core taken from Northwest Greenland. Evidence suggests this soil was last at the surface during Marine Isotope Stage 11 around 416,000 years ago. Using this information in combination with ice sheet simulations allowed the team to determine that Greenland contributed at least 5 feet to global sea level at this time. Greenhouse gas concentrations were significantly lower at 416,000 years ago than they are today, which suggests the Greenland ice sheet may be less stable than previously thought and has important implications for future climate change.