Drivers of observed Antarctic sea ice trends and variability

2023 was an extraordinary year for Antarctic sea ice, with a second consecutive record minimum in February, followed by the first ever ‘extreme’ sea ice cover in winter. However, even before 2023 scientists were suggesting that Antarctic sea ice may have undergone a regime shift, marked by a sudden transition in 2016 from a multidecadal positive trend to a persistent low sea ice cover state. To fully test this claim, we need to consider the potential drivers – whether anthropogenic or natural – of such a shift. In this talk I will give an overview of the primary physical drivers of Antarctic sea ice variability, and will consider the evidence that those drivers have altered in the last decade.