SciencePrehistoric (c. 11,700 years ago)Global (Greenland ice core data)high confidence

The warming that ended the Younger Dryas took only about 40–50 years.

Notes on verification

Confirmed by multiple independent paleoclimate sources including foundational Nature paper (Dansgaard et al. 1989), National Academies review, and other ice-core studies. Minor variation in exact figures (10-60 years) across studies but all support an abrupt, decades-scale warming consistent with 40-50 year claim. [tier=gold indep_score=0.95 clusters=3 claim_tier=notable]

Sources