SciencePrehistoric (Cretaceous-Paleogene boundary, ~66 million years ago)globalhigh confidence

During the global winter caused by the asteroid impact, temperatures fell below freezing.

Notes on verification

Corroborated by multiple peer-reviewed studies (PNAS, GRL, Nature Geoscience) and institutional summaries (LPI/USRA, AGU) consistently reporting sub-freezing global temperatures following the Chicxulub impact. [tier=gold indep_score=0.95 clusters=3 claim_tier=notable]

Sources

During the global winter caused by the asteroid impact, t… · DeepInquiry