According to NOAA, ocean pH has fallen by 0.1 units over the past 200 years, making ocean waters 30 percent more acidic.
Notes on verification
Verbatim confirmed by NOAA's own pages and independently corroborated by Smithsonian, a peer-reviewed 2023 study, and a 2025 University of Washington release. Minor rounding difference (0.1 vs 0.11) does not affect accuracy. [tier=gold indep_score=1.0 clusters=4 claim_tier=notable]
Sources
- The Pacific Ocean—facts and information (seed:science_and_space)
- https://www.noaa.gov/education/resource-collections/ocean-coasts/ocean-acidification (corroboration)
- https://www.pmel.noaa.gov/co2/story/What+is+Ocean+Acidification%253F (corroboration)
- https://ocean.si.edu/ocean-life/invertebrates/ocean-acidification (corroboration)
- https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2022MS003563 (corroboration)
- https://www.washington.edu/news/2025/11/13/carbon-rich-waters-are-becoming-more-acidic-faster/ (corroboration)