{ "region": "antarctic", "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-antarctic", "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-antarctic", "previousBriefingId": "2026-10-08-antarctic", "dataThrough": "2026-10-16", "observationPeriod": [ "2026-10-01", "2026-10-16" ], "value": "10.9", "unit": "%", "valueLabel": "Below the same-day average", "baselineLabel": "1981–2010 reference period", "mapHref": "#extent-title", "mapLabel": "Explore the sea-ice record", "evidence": { "reading": { "date": "2026-10-16", "year": 2026, "month": 10, "day": 16, "extentMillionKm2": 16.225, "missingMillionKm2": 0.0, "accepted": true, "baselineMean": 18.200107142857142, "sampleSD": 0.36402669207035154, "referenceYears": 28, 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"excludedRecentRows": [ { "date": "2026-10-17", "year": 2026, "month": 10, "day": 17, "extentMillionKm2": 16.204, "missingMillionKm2": 0.382, "accepted": false } ], "dailyComparisons": [ { "date": "2026-10-01", "year": 2026, "month": 10, "day": 1, "extentMillionKm2": 16.851, "missingMillionKm2": 0.0, "accepted": true, "baselineMean": 18.570461538461537, "sampleSD": 0.3662584039466376, "referenceYears": 26, "differenceMillionKm2": -1.7194615384615375, "differencePercent": -9.259121185008446, "rangeLower": 17.83794473056826, "rangeUpper": 19.302978346354813, "rangePosition": "below" }, { "date": "2026-10-02", "year": 2026, "month": 10, "day": 2, "extentMillionKm2": 16.65, "missingMillionKm2": 0.0, "accepted": true, "baselineMean": 18.515428571428572, "sampleSD": 0.4037271198490231, "referenceYears": 28, "differenceMillionKm2": -1.8654285714285734, "differencePercent": -10.074995370656143, "rangeLower": 17.707974331730526, "rangeUpper": 19.322882811126618, "rangePosition": "below" }, { "date": "2026-10-03", "year": 2026, "month": 10, "day": 3, "extentMillionKm2": 16.739, "missingMillionKm2": 0.0, "accepted": true, "baselineMean": 18.554423076923076, "sampleSD": 0.3595796627260137, "referenceYears": 26, "differenceMillionKm2": -1.815423076923075, "differencePercent": -9.784314335167844, "rangeLower": 17.835263751471047, "rangeUpper": 19.273582402375105, "rangePosition": "below" }, { "date": "2026-10-04", "year": 2026, "month": 10, "day": 4, "extentMillionKm2": 16.798, "missingMillionKm2": 0.0, "accepted": true, "baselineMean": 18.480607142857142, "sampleSD": 0.4100068056603828, "referenceYears": 28, "differenceMillionKm2": -1.6826071428571439, "differencePercent": -9.104717879939788, "rangeLower": 17.660593531536378, "rangeUpper": 19.300620754177906, "rangePosition": "below" }, { "date": "2026-10-05", "year": 2026, "month": 10, "day": 5, "extentMillionKm2": 16.776, "missingMillionKm2": 0.0, "accepted": true, "baselineMean": 18.51076923076923, "sampleSD": 0.36187592433786575, "referenceYears": 26, "differenceMillionKm2": -1.7347692307692313, "differencePercent": -9.371675531914896, "rangeLower": 17.7870173820935, "rangeUpper": 19.234521079444963, "rangePosition": "below" }, { "date": "2026-10-06", "year": 2026, "month": 10, "day": 6, "extentMillionKm2": 16.706, "missingMillionKm2": 0.0, "accepted": true, "baselineMean": 18.44275, "sampleSD": 0.3840741272009677, "referenceYears": 28, "differenceMillionKm2": -1.7367500000000007, "differencePercent": -9.416979571918509, "rangeLower": 17.674601745598064, "rangeUpper": 19.210898254401936, "rangePosition": "below" }, { "date": "2026-10-07", "year": 2026, "month": 10, "day": 7, "extentMillionKm2": 16.71, "missingMillionKm2": 0.0, "accepted": true, "baselineMean": 18.475192307692307, "sampleSD": 0.3476581101289908, "referenceYears": 26, "differenceMillionKm2": -1.7651923076923062, "differencePercent": -9.554392064202508, "rangeLower": 17.779876087434324, "rangeUpper": 19.17050852795029, "rangePosition": "below" }, { "date": "2026-10-08", "year": 2026, "month": 10, "day": 8, "extentMillionKm2": 16.584, "missingMillionKm2": 0.0, "accepted": true, "baselineMean": 18.392714285714284, "sampleSD": 0.389885249703689, "referenceYears": 28, "differenceMillionKm2": -1.8087142857142844, "differencePercent": -9.83386278728378, "rangeLower": 17.612943786306907, "rangeUpper": 19.17248478512166, "rangePosition": "below" }, { "date": "2026-10-09", "year": 2026, "month": 10, "day": 9, "extentMillionKm2": 16.563, "missingMillionKm2": 0.0, "accepted": true, "baselineMean": 18.408192307692307, "sampleSD": 0.33412608628848695, "referenceYears": 26, "differenceMillionKm2": -1.845192307692308, "differencePercent": -10.023756145361704, "rangeLower": 17.739940135115333, "rangeUpper": 19.07644448026928, "rangePosition": "below" }, { "date": "2026-10-10", "year": 2026, "month": 10, "day": 10, "extentMillionKm2": 16.516, "missingMillionKm2": 0.0, "accepted": true, "baselineMean": 18.319107142857142, "sampleSD": 0.38686875363575496, "referenceYears": 28, "differenceMillionKm2": -1.8031071428571437, "differencePercent": -9.84276760213283, "rangeLower": 17.545369635585633, "rangeUpper": 19.09284465012865, "rangePosition": "below" }, { "date": "2026-10-11", "year": 2026, "month": 10, "day": 11, "extentMillionKm2": 16.526, "missingMillionKm2": 0.0, "accepted": true, "baselineMean": 18.35776923076923, "sampleSD": 0.3125564662831097, "referenceYears": 26, "differenceMillionKm2": -1.831769230769229, "differencePercent": -9.978168958018184, "rangeLower": 17.73265629820301, "rangeUpper": 18.982882163335447, "rangePosition": "below" }, { "date": "2026-10-12", "year": 2026, "month": 10, "day": 12, "extentMillionKm2": 16.45, "missingMillionKm2": 0.0, "accepted": true, "baselineMean": 18.284535714285713, "sampleSD": 0.3644888335578468, "referenceYears": 28, "differenceMillionKm2": -1.834535714285714, "differencePercent": -10.0332638627099, "rangeLower": 17.55555804717002, "rangeUpper": 19.013513381401406, "rangePosition": "below" }, { "date": "2026-10-13", "year": 2026, "month": 10, "day": 13, "extentMillionKm2": 16.362, "missingMillionKm2": 0.0, "accepted": true, "baselineMean": 18.315269230769232, "sampleSD": 0.3033286742386621, "referenceYears": 26, "differenceMillionKm2": -1.9532692307692336, "differencePercent": -10.664703893556673, "rangeLower": 17.70861188229191, "rangeUpper": 18.921926579246556, "rangePosition": "below" }, { "date": "2026-10-14", "year": 2026, "month": 10, "day": 14, "extentMillionKm2": 16.346, "missingMillionKm2": 0.0, "accepted": true, "baselineMean": 18.244107142857143, "sampleSD": 0.3718334293824978, "referenceYears": 28, "differenceMillionKm2": -1.8981071428571425, "differencePercent": -10.403946479783098, "rangeLower": 17.500440284092146, "rangeUpper": 18.98777400162214, "rangePosition": "below" }, { "date": "2026-10-15", "year": 2026, "month": 10, "day": 15, "extentMillionKm2": 16.33, "missingMillionKm2": 0.0, "accepted": true, "baselineMean": 18.271115384615385, "sampleSD": 0.307461779988743, "referenceYears": 26, "differenceMillionKm2": -1.9411153846153866, "differencePercent": -10.623956686573395, "rangeLower": 17.656191824637897, "rangeUpper": 18.886038944592872, "rangePosition": "below" }, { "date": "2026-10-16", "year": 2026, "month": 10, "day": 16, "extentMillionKm2": 16.225, "missingMillionKm2": 0.0, "accepted": true, "baselineMean": 18.200107142857142, "sampleSD": 0.36402669207035154, "referenceYears": 28, "differenceMillionKm2": -1.9751071428571407, "differencePercent": -10.852173162245894, "rangeLower": 17.472053758716438, "rangeUpper": 18.928160526997846, "rangePosition": "below" } ], "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": "Sea-ice extent nearly two million km² below the seasonal average.", "copy": "Antarctic sea-ice extent was 1.98 million km² below the 1981–2010 average for 16 October, a shortfall of 10.9%. All 16 accepted October readings lay below our descriptive historical comparison range. NASA reports that September’s winter maximum was the third lowest in the satellite record. These comparisons describe coverage; they do not establish local wildlife impacts. The newer, incomplete reading is excluded.", "selectionReason": "Owner approved the shortfall and low winter-maximum angle. Keep the 16 October daily shortfall separate from the 14 September annual maximum. Exclude 17 October incomplete coverage; no present-day record-low claim.", "editorialAssessment": { "analyse": "Antarctic extent was 16.225 million km² on 2026-10-16, compared with 18.200 million km² for the same-calendar-day 1981–2010 reference. The difference is -1.975 million km², or -10.9%. The change since 6 October is -0.481 million km². The seasonal anomaly and the change over time are separate comparisons.", "evaluate": "The reference uses 28 accepted years. The latest reading is below 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 annual maximum reached 17.59 million km² on 14 September, third lowest 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. The Antarctic 17 October row has 0.382 million km² of missing coverage and is excluded.", "contextSources": [ { "title": "NASA: Antarctic Sea Ice Grows to Its 2026 Maximum", "url": "https://science.nasa.gov/earth/earth-observatory/antarctic-sea-ice-grows-to-its-2026-maximum/", "publishedAt": "2026-10-12", "verifiedAt": "2026-10-22", "observationPeriod": "2026-09-14 annual maximum", "finding": "The annual maximum reached 17.59 million km² on 14 September, third lowest in the satellite record." } ], "archivedInputs": "/briefings/evidence/2026-10-22-antarctic-inputs.json", "archivedInputsSha256": "511829fd19c53f1a92de097880dc80dcd1fc596a911d436cfd17a70938a2ac39", "finalSourceCheckRequired": false, "reviewRequired": false, "wordCount": 61, "publicationApprovedAt": "2026-10-22T10:50:26.173432+00:00" }