| Summary: | Over the modern satellite era, substantial connected climatic changes have been observed in the Antarctic, including atmospheric and oceanic warming in West Antarctica and on the Antarctic Peninsula, accelerating ice sheet thinning, and accompanied by expanding sea ice area followed more recently by sea ice loss. Although forced by increasing emissions of greenhouse gases and Antarctic ozone depletion, the observed Antarctic changes, characterized by strong zonally asymmetric features, have been partially attributed to tropical-polar teleconnections, primarily through Rossby wave dynamics. In this Review, we synthesize understanding of tropical teleconnections to the Southern Hemisphere extratropics, focusing on the physical mechanisms and climatic impacts on multi-decadal timescales. These teleconnections contributed to a range of observed Antarctic and Southern Ocean changes, including regional rapid surface warming, pre-2015 sea ice expansion and its sudden reduction thereafter, changes in ocean heat content, and accelerated thinning of most of the Antarctic ice sheet. However, due to limited observations and inherent model biases, uncertainties remain in understanding and assessing the importance of these teleconnections versus those due to greenhouse gases, ozone recovery, and southern-hemispheric high-latitude internal variability (for example, the Southern Annular Mode). Further progress will be enabled through sustained efforts towards long-term observations with a pan-Antarctic approach, and high-resolution climate models with more realistic dynamics and parameterizations.
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