Global warming has caused a significant decrease in sea ice coverage in the Arctic. This is having far reaching implications for the ecosystems, as well as dramatically changing the way that humans interact with the Arctic environment. Climate models predicted that a similar decrease in sea ice would occur in the Antarctic. However, since regular observations began in 1979, the sea ice extent in the Antarctic has been increasing. We review current research that identifies numerous atmospheric and oceanic factors that are influencing sea ice trends. These factors have helped to explain some of the changes observed in sea ice extent at a regional level, but still do not accurately predict sea ice trends for the Southern Ocean as whole. A significant anomaly in sea ice extent that occurred in the austral spring of 2016-17 has confounded scientists, and highlights the limitations of current science and climate models to foresee the trend in sea ice in the Antarctic. Furthermore, we explore the potential implications for Antarctic ecosystems through a review of current literature. This emphasises the critical role of sea ice in the life history of a vast majority of Antarctic species, making them extremely vulnerable to changes in sea ice extent. Finally, we consider the implications for human activities in the Antarctic through a series of case studies. These identify the organisations and industries that will be affected by changes in sea ice, and who will rely on the development of accurate models and predictions to safely plan their future activities in the Antarctic.