---
chapter:
  doi: 10.7930/J0QV3JQB
  identifier: ocean-acidification
  number: 13
  report_identifier: climate-science-special-report
  sort_key: 15
  title: Ocean Acidification and Other Ocean Changes
  url: https://science2017.globalchange.gov/chapter/13/
chapter_identifier: ocean-acidification
cited_by: []
confidence: ~
contributors: []
evidence: 'The key finding and supporting text summarizes the evidence documented in climate science literature including Rhein et al. 2013,<tbib>bc140b4c-c2d9-4d99-a684-5c054dc5134f</tbib> Bopp et al. 2013,<tbib>fa10bfab-8f7c-4d8c-8435-8284a05d78e5</tbib> and Schmidtko et al. 2017.<tbib>b2a0160d-032f-4a96-8cb1-321e09950172</tbib> Evidence arises from extensive global measurements of the WOCE after 1989 and individual profiles before that.<tbib>2dbd3f8b-a4f8-421f-b75f-8cb165b1a867</tbib> The first basin-wide dissolved oxygen surveys were performed in the 1920s.<tbib>b2a0160d-032f-4a96-8cb1-321e09950172</tbib> The confidence level is based on globally integrated O<sub>2</sub> distributions in a variety of ocean models. Although the global mean exhibits low interannual variability, regional contrasts are large.'
files: []
gcmd_keywords: []
href: https://data.globalchange.gov/report/climate-science-special-report/chapter/ocean-acidification/finding/key-finding-13-4.yaml
identifier: key-finding-13-4
ordinal: 4
parents:
  - activity_uri: ~
    label: 'figure -.2: Confidence / Likelihood'
    note: ''
    publication_type_identifier: figure
    relationship: prov:wasDerivedFrom
    url: /report/climate-science-special-report/chapter/front-matter/figure/confidence---likelihood
process: 'Major ocean deoxygenation is taking place in bodies of water inland, at estuaries, and in the coastal and the open ocean (<em>high confidence</em>). Regionally, the phenomenon is exacerbated by local changes in weather, ocean circulation, and continental inputs to the oceans.'
references:
  - href: https://data.globalchange.gov/reference/2dbd3f8b-a4f8-421f-b75f-8cb165b1a867.yaml
    uri: /reference/2dbd3f8b-a4f8-421f-b75f-8cb165b1a867
  - href: https://data.globalchange.gov/reference/b2a0160d-032f-4a96-8cb1-321e09950172.yaml
    uri: /reference/b2a0160d-032f-4a96-8cb1-321e09950172
  - href: https://data.globalchange.gov/reference/bc140b4c-c2d9-4d99-a684-5c054dc5134f.yaml
    uri: /reference/bc140b4c-c2d9-4d99-a684-5c054dc5134f
  - href: https://data.globalchange.gov/reference/fa10bfab-8f7c-4d8c-8435-8284a05d78e5.yaml
    uri: /reference/fa10bfab-8f7c-4d8c-8435-8284a05d78e5
regions: []
report_identifier: climate-science-special-report
statement: 'Increasing sea surface temperatures, rising sea levels, and changing patterns of precipitation, winds, nutrients, and ocean circulation are contributing to overall declining oxygen concentrations at intermediate depths in various ocean locations and in many coastal areas. Over the last half century, major oxygen losses have occurred in inland seas, estuaries, and in the coastal and open ocean (<em>high confidence</em>). Ocean oxygen levels are projected to decrease by as much as 3.5% under the higher scenario (RCP8.5) by 2100 relative to preindustrial values (<em>high confidence</em>).'
uncertainties: 'Uncertainties (as estimated from the intermodel spread) in the global mean are moderate mainly because ocean oxygen content exhibits low interannual variability when globally averaged. Uncertainties in long-term decreases of the global averaged oxygen concentration amount to 25% in the upper 1,000 m for the 1970–1992 period and 28% for the 1993–2003 period. Remaining uncertainties relate to regional variability driven by mesoscale eddies and intrinsic climate variability such as ENSO.'
uri: /report/climate-science-special-report/chapter/ocean-acidification/finding/key-finding-13-4
url: ~