Science2010sNorth America / Pacific Oceanhigh 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

Directly corroborated by multiple independent sources including National Geographic reporting with a matching quote from Gentemann, plus NASA, NPS, and California EPA documents supporting the broader claim of the Blob's unprecedented nature. [tier=gold indep_score=1.0 clusters=4 claim_tier=notable]

Sources