SciencePrehistoric/PleistoceneGreenlandhigh confidence

Greenland Ice-core Project/Greenland Ice Sheet Project 2 (GRIP/GISP2) ice cores preserve climate records extending back more than 100,000 years.

Notes on verification

Multiple independent peer-reviewed studies and agency (NOAA, NSF) archives corroborate GRIP/GISP2 ice cores span ~100,000-110,000+ years, consistent with the claim.

Sources