Summary
Net sea-ice extent (SIE) and sea-ice area (SIA) were well below or at record-low levels for all of 2022 (based on satellite passive-microwave ice concentration data since 1979 when the near-homogenous satellite record began; Cavalieri et al. 1996). Indeed, there were more than 80 record low daily values of SIE and SIA (Fig. 6.11a, with most occurring during the late 2021/22 retreat and early 2022/23 advance phase (January–March), the wintertime phase (June–September), and the mid 2022/23 retreat phase (December). A new record-low SIE annual daily minimum of ~1.96 × 106 km2 was recorded on 25 February (Turner et al. 2022; Wang et al. 2022; NSIDC 2022), breaking the previous record of ~2.08 × 106 km2 on 1 March 2017 (Turner and Comiso 2017; Reid et al. 2018) using the same sea-ice concentration dataset. The annual daily minimum of SIA (~1.25 × 106 km2 on 20 February) was also a record low value, while the 2022 annual daily maximum SIE of ~18.28 × 106 km2 (recorded on 13 September) was the fifth lowest on record. Three months (February, June, and July) observed record-low monthly-mean values of SIE, while there were five months of record-low monthly values of SIA throughout the year. The record-low monthly SIEs continue a recent trend since January 2016, whereby over 85% (72 out of 84) of monthly net SIE values have been below the long-term (1991–2020) average. This reduction in SIE has been most prominent in the late retreat phases (January and February) where net SIE has been below average or at record-low values for every year (2016–22). Fraser et al. (2023) observed record-low values of coastal fast ice area in 2022, along with record-high values of coastal exposure (which refers to the length of coastline without offshore sea ice cover; Reid and Massom 2022). Regionally and after May, the Ross Sea, then Amundsen Sea, experienced generally much greater-than-average SIE, while most other sectors recorded average or lower-than-average SIE throughout the year (Figs. 6.11b,d). Regional and temporal variations are discussed more fully below and closely reflect the three atmospheric phases shown in Figs. 6.2 and 6.3 (see section 6b).
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