{ "region": "arctic", "methodsHref": "/data.html#polar-records", "source": "NOAA/NSIDC Sea Ice Index, Version 4", "sourceUrl": "https://nsidc.org/data/g02135/versions/4", "id": "2026-10-22-arctic", "status": "published", "draftedAt": "2026-10-22", "plannedPublicationAt": "2026-10-22T11:00:00+01:00", "publishedAt": "2026-10-22", "reviewedAt": "2026-10-22", "evidenceHref": "/data.html#briefing-2026-10-22-arctic", "previousBriefingId": "2026-10-08-arctic", "dataThrough": "2026-10-17", "observationPeriod": [ "2026-10-01", "2026-10-17" ], "value": "19.7", "unit": "%", "valueLabel": "Below the same-day average", "baselineLabel": "1981–2010 reference period", "mapHref": "#extent-title", "mapLabel": "Explore the sea-ice record", "evidence": { "reading": { "date": "2026-10-17", "year": 2026, "month": 10, "day": 17, "extentMillionKm2": 6.717, "missingMillionKm2": 0.0, "accepted": true, "baselineMean": 8.3645, "sampleSD": 0.8988857213239067, "referenceYears": 26, "differenceMillionKm2": -1.6475, 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"within" }, { "date": "2026-10-15", "year": 2026, "month": 10, "day": 15, "extentMillionKm2": 6.809, "missingMillionKm2": 0.0, "accepted": true, "baselineMean": 8.181423076923076, "sampleSD": 0.9321752270073228, "referenceYears": 26, "differenceMillionKm2": -1.3724230769230763, "differencePercent": -16.774869897563423, "rangeLower": 6.317072622908431, "rangeUpper": 10.045773530937723, "rangePosition": "within" }, { "date": "2026-10-16", "year": 2026, "month": 10, "day": 16, "extentMillionKm2": 6.731, "missingMillionKm2": 0.0, "accepted": true, "baselineMean": 8.328642857142857, "sampleSD": 0.9095122100980616, "referenceYears": 28, "differenceMillionKm2": -1.5976428571428567, "differencePercent": -19.182511299216984, "rangeLower": 6.509618436946734, "rangeUpper": 10.14766727733898, "rangePosition": "within" }, { "date": "2026-10-17", "year": 2026, "month": 10, "day": 17, "extentMillionKm2": 6.717, "missingMillionKm2": 0.0, "accepted": true, "baselineMean": 8.3645, "sampleSD": 0.8988857213239067, "referenceYears": 26, "differenceMillionKm2": -1.6475, "differencePercent": -19.6963357044653, "rangeLower": 6.566728557352186, "rangeUpper": 10.162271442647812, "rangePosition": "within" } ], "limitations": [ "Daily provisional values may be revised. No measurement-error interval in this CSV. Zero Missing is not zero uncertainty.", "Mean ±2 sample SD is a descriptive reference band, not a confidence interval, event probability or attribution." ] }, "method": { "baseline": "1981–2010", "kind": "Accepted same-calendar-day reference mean and sample SD(n−1); zero source Missing and nonnegative extent required.", "limitations": [ "Daily provisional values may be revised. No measurement-error interval in this CSV. Zero Missing is not zero uncertainty.", "Mean ±2 sample SD is a descriptive reference band, not a confidence interval, event probability or attribution." ], "citation": "Fetterer et al.(2025), Sea Ice Index,G02135,Version4,doi:10.7265/a98x-0f50. October subsets and complete-coverage same-calendar-day records, accessed22October2026." }, "headline": "Autumn ice returns against a backdrop of long-term loss.", "copy": "Between 6 and 17 October, Arctic sea-ice extent grew by 758,000 km², but remained 19.7% below the 1981–2010 average for that date. Seasonal growth sits within a longer decline: NSIDC reports that 2007–2026 account for the 20 lowest annual summer minima in the satellite record. This hemisphere-wide comparison does not establish ice thickness or local wildlife impacts.", "selectionReason": "Owner approved the seasonal-growth and long-term-loss angle. Distinguish the current daily comparison from published annual-minimum context; do not describe seasonal growth as recovery.", "editorialAssessment": { "analyse": "Arctic extent was 6.717 million km² on 2026-10-17, compared with 8.364 million km² for the same-calendar-day 1981–2010 reference. The difference is -1.647 million km², or -19.7%. The change since 6 October is +0.758 million km². The seasonal anomaly and the change over time are separate comparisons.", "evaluate": "The reference uses 26 accepted years. The latest reading is within the descriptive mean ± two sample-standard-deviation band. Daily persistence and same-day historical comparisons are archived. This band is not a confidence interval, event probability or annual record. Daily values can be revised; zero missing coverage does not mean zero measurement uncertainty. Published context: The 20 years from 2007 to 2026 account for the 20 lowest annual Arctic minima in the satellite record. Its observation period is separate from this daily reading.", "explain": "Sea-ice extent describes hemisphere-wide coverage at the15% concentration threshold. Sea ice affects ocean–air exchange and habitat in general, but this hemisphere statistic alone cannot demonstrate local wildlife or community impacts. Thickness, ice duration, local exposure, causes and attribution are not established here." }, "providerAvailabilityNote": "NSIDC product-page maintenance notice verified 22 October. Latest usable source dates rechecked 22 October; the provider file is unchanged.", "contextSources": [ { "title": "NSIDC: Arctic sea ice minimum ties for tenth lowest", "url": "https://nsidc.org/sea-ice-today/analyses/arctic-sea-ice-minimum-ties-tenth-lowest-0", "publishedAt": "2026-09-23", "verifiedAt": "2026-10-22", "observationPeriod": "Annual summer minima, 2007–2026", "finding": "The 20 years from 2007 to 2026 account for the 20 lowest annual Arctic minima in the satellite record." } ], "archivedInputs": "/briefings/evidence/2026-10-22-arctic-inputs.json", "archivedInputsSha256": "e11da5ef70f95f3923527ca3d71aceab9a5433e3d00a7d960c9fce3c7b44013e", "finalSourceCheckRequired": false, "reviewRequired": false, "wordCount": 57, "publicationApprovedAt": "2026-10-22T10:50:26.173432+00:00" }