Science2010sPacific Ocean / North America west coasthigh confidence

Chelle Gentemann compared the Pacific 'Blob' with sea-surface-temperature records dating back to 1910 and found its magnitude and duration were unprecedented in that historical record.

Notes on verification

Core claim (unprecedented magnitude/duration) is corroborated by NPS and a state climate report citing peer-reviewed literature; the specific 1910 baseline detail traces back to the same National Geographic reporting lineage, not independently verified. [tier=gold indep_score=0.983 clusters=3 claim_tier=notable]

Sources