{
  "attribution": "Calculated by Environment Dashboard from HadSST.4.2.0.0. HadSST.4.2.0.0 data were obtained from http://www.metoffice.gov.uk/hadobs/hadsst4 on 2026-10-05 and are © British Crown Copyright, Met Office 2025, provided under an Open Government Licence, https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/ Changes: range shown as the anomaly minus and plus the published total uncertainty (one standard deviation).",
  "description": "Global mean sea-surface temperature for each complete year since 1850, from ship and buoy measurements, as the difference from the 1961–1990 average, with a one-standard-deviation range.",
  "dimensions": [],
  "display": {
    "decimals": 2
  },
  "geo_coverage": "global-only",
  "headline_entity": "WLD",
  "id": "sst.hadsst4.annual-1961-1990",
  "kind": "series",
  "latest": {
    "age_bp": null,
    "dims": {},
    "entity": "WLD",
    "period": "2025",
    "status": "final",
    "value": 0.839189
  },
  "licence": {
    "name": "Open Government Licence v3.0 (Crown copyright)",
    "spdx": "OGL-UK-3.0",
    "url": "https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/"
  },
  "licence_class": "open",
  "notes": [],
  "notice": null,
  "origins": [
    {"acquisition": "automatic", "artifact_id": "global-annual", "bytes": 14097, "citation_full": "Kennedy, J. J., Rayner, N. A., Atkinson, C. P., & Killick, R. E., 2019. An Ensemble Data Set of Sea Surface Temperature Change from 1850: The Met Office Hadley Centre HadSST.4.0.0.0 Data Set. Journal of Geophysical Research: Atmospheres, 124. https://doi.org/10.1029/2018JD029867. Sandford, C., and Rayner, N., 2026. Addressing the World War 2 Warm Anomaly in HadSST.4.2.0.0. International Journal of Climatology. https://doi.org/10.1002/joc.70388.", "date_accessed": "2026-10-05", "date_published": null, "doi": "10.1029/2018JD029867", "etag": "\"3711-65b81f9231a40\"", "last_modified": "Tue, 15 Sep 2026 09:14:09 GMT", "licence": {"name": "Open Government Licence v3.0 (Crown copyright)", "spdx": "OGL-UK-3.0", "url": "https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/"}, "producer": "Met Office Hadley Centre", "r2_url": "https://files.environmentdashboard.org/raw/38dd997dc6716cdae019e41d37a5436178d07554a7d69287411904c14e67fa01.zst", "sha256": "38dd997dc6716cdae019e41d37a5436178d07554a7d69287411904c14e67fa01", "source_id": "hadsst4", "title": "HadSST.4 sea-surface temperature anomalies", "url_download": "https://www.metoffice.gov.uk/hadobs/hadsst4/data/data/HadSST.4.2.0.0_annual_GLOBE.csv", "url_main": "https://www.metoffice.gov.uk/hadobs/hadsst4/", "version_producer": "4.2.0.0", "wayback_url": null},
    {"acquisition": "automatic", "artifact_id": "global-monthly", "bytes": 172297, "citation_full": "Kennedy, J. J., Rayner, N. A., Atkinson, C. P., & Killick, R. E., 2019. An Ensemble Data Set of Sea Surface Temperature Change from 1850: The Met Office Hadley Centre HadSST.4.0.0.0 Data Set. Journal of Geophysical Research: Atmospheres, 124. https://doi.org/10.1029/2018JD029867. Sandford, C., and Rayner, N., 2026. Addressing the World War 2 Warm Anomaly in HadSST.4.2.0.0. International Journal of Climatology. https://doi.org/10.1002/joc.70388.", "date_accessed": "2026-10-05", "date_published": null, "doi": "10.1029/2018JD029867", "etag": "\"2a109-65b81f9231a40\"", "last_modified": "Tue, 15 Sep 2026 09:14:09 GMT", "licence": {"name": "Open Government Licence v3.0 (Crown copyright)", "spdx": "OGL-UK-3.0", "url": "https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/"}, "producer": "Met Office Hadley Centre", "r2_url": "https://files.environmentdashboard.org/raw/07444a0e9be79dfe546f29d34e8dbbf561036e172b89eea45c3487c2b58dada6.zst", "sha256": "07444a0e9be79dfe546f29d34e8dbbf561036e172b89eea45c3487c2b58dada6", "source_id": "hadsst4", "title": "HadSST.4 sea-surface temperature anomalies", "url_download": "https://www.metoffice.gov.uk/hadobs/hadsst4/data/data/HadSST.4.2.0.0_monthly_GLOBE.csv", "url_main": "https://www.metoffice.gov.uk/hadobs/hadsst4/", "version_producer": "4.2.0.0", "wayback_url": null}
  ],
  "processing": [
    {
      "description": "Read the global annual series of HadSST.4.2.0.0 (sea-surface temperature anomaly in kelvin relative to 1961–1990, as published; a difference of 1 K equals 1 °C, so the values are unchanged). The file holds complete years, 1850 to 2025; each was confirmed to have all 12 months in the global monthly file.",
      "inputs": ["38dd997dc6716cdae019e41d37a5436178d07554a7d69287411904c14e67fa01", "07444a0e9be79dfe546f29d34e8dbbf561036e172b89eea45c3487c2b58dada6"],
      "lock_sha256": "7e110986c30381965c2e6096466c401cbf72bd1b7a828369f6f6c14c909dcbda",
      "script": "pipeline/src/envdash/transforms/temperature/hadsst4.py",
      "transform_sha256": "d556dbda6cbcbcbc49a8268c77c5c8258ccb5de152fb04cb6fe453af2d2f716e"
    },
    {
      "description": "Lower and upper are the anomaly minus and plus the file's total_uncertainty, which the Product User Guide defines as the 1σ uncertainty combining uncorrelated measurement, sampling, correlated measurement, bias-correction and coverage uncertainties. The file's 95% bounds cover bias uncertainty only and are not used.",
      "inputs": ["38dd997dc6716cdae019e41d37a5436178d07554a7d69287411904c14e67fa01", "07444a0e9be79dfe546f29d34e8dbbf561036e172b89eea45c3487c2b58dada6"],
      "lock_sha256": "7e110986c30381965c2e6096466c401cbf72bd1b7a828369f6f6c14c909dcbda",
      "script": "pipeline/src/envdash/transforms/temperature/hadsst4.py",
      "transform_sha256": "d556dbda6cbcbcbc49a8268c77c5c8258ccb5de152fb04cb6fe453af2d2f716e"
    }
  ],
  "published_value": null,
  "schema_version": 1,
  "scope": {
    "baseline": "1961–1990, the dataset's own baseline (as published)",
    "basis": "In situ sea-surface temperature from ships and buoys, adjusted for changes in how it was measured.",
    "bunkers": null,
    "geography": "Global ocean, averaged over 5° grid boxes that have measurements (not interpolated)",
    "gwp": null,
    "lulucf": null
  },
  "superseded_by": null,
  "table": {
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  },
  "time_basis": "calendar",
  "title": "Global sea-surface temperature against 1961–1990 (HadSST4)",
  "unit": {
    "code": "degC",
    "label": "degrees Celsius",
    "short": "°C"
  },
  "vintage": "4.2.0.0"
}