# Ariaan Purich: Warming of Circumpolar Deep Water drives Antarctic sea ice loss **URL:** \ **Category:** ESM/Land/CMIP7 Workshop 2026 Lightnings Talks\ **Created:** [20 August 2026 05:41 UTC](https://forum.access-hive.org.au/t/ariaan-purich-warming-of-circumpolar-deep-water-drives-antarctic-sea-ice-loss/6873 "2026-08-20T05:41:55Z")\ **Posts on this page:** 1\ **Page:** 1
**Author:** ![lachlanswhyborn](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.access-hive.org.au/lachlanswhyborn/32/1837_2.png) [@lachlanswhyborn](https://forum.access-hive.org.au/u/lachlanswhyborn)\ **Post date:** [20 August 2026 05:41 UTC](https://forum.access-hive.org.au/t/ariaan-purich-warming-of-circumpolar-deep-water-drives-antarctic-sea-ice-loss/6873/1 "2026-08-20T05:41:55Z")
Ariaan Purich: Warming of Circumpolar Deep Water drives Antarctic sea ice loss Antarctic sea ice coverage dropped to unprecedented record-low levels in the winter of 2023 and has remained exceptionally low since. Warm subsurface waters have been proposed as a driver of these losses, but the link between subsurface ocean warming and sea ice decline remains unclear. Here we use a set of perturbed coupled climate model simulations with an anomalously warm Circumpolar Deep Water (CDW) layer to explore this link. The imposed subsurface warming drives a winter decline of Antarctic sea ice that matches the magnitude and seasonality of the record-low extents observed since 2023. The decline is initiated by the upwelling of anomalously warm CDW, sustained by summer ice–albedo feedbacks, and partially offset by enhanced winter heat loss from the ocean. This causes sea ice to stabilise at a new lower equilibrium rather than initiating a runaway decline. Importantly, the decline imprints more strongly on sea ice thickness than sea ice concentration, suggesting that satellite observations may underestimate the total volume of recent Antarctic sea ice loss.