Recent years have seen unprecedented lows in Antarctic sea-ice extent, raising questions about the underlying drivers and whether the current loss lies within the envelope of past variability or signals a regime shift. This talk synthesises several newly homogenised reconstructions that span the entire twentieth century, built from a combination of whaling-log climatologies, satellite proxies, climate reanalyses, and coupled model constraints. By comparing these historical reconstructions with the satellite record (1979-present) we quantify the amplitude and spatial pattern of natural variability and evaluate the apparent downward trend observed since 2016. The results place the recent anomalies in a longer-term context and help identify the physical mechanisms—particularly zonal-mean wind changes and oceanic heat transport—that modulate sea-ice extent on decadal scales.
Implications for Antarctic climate feedbacks and Southern Ocean ecosystems will be discussed, along with the limitations of the reconstruction approach and priorities for future data rescue.