Research progress and challenges of rapid changes and mechanisms of polar sea ice

Polar sea ice is essential to the Earth system, functioning as both an indicator and amplifier of climatic and environmental changes. In the context of global warming, Arctic sea ice has diminished during the past 46 years, but Antarctic sea ice has had an increase followed by a significant decline. Currently, both polar sea ice regions have reached unprecedented low levels sequentially. Changes in polar sea ice are associated with anthropogenic global warming and internal climate variability. Over the past four decades, researchers have obtained fruitful findings about polar sea ice changes and potential processes by integrating field observations, satellite remote sensing, reanalysis data, and numerical simulations. Nonetheless, the precise factors for its rapid changes and their individual contributions remain inadequately comprehended. This study summarizes the characteristics of Arctic and Antarctic sea ice alterations observed in recent decades and projections of future changes. It systematically elucidates the progress and challenges of the rapid change mechanisms of Arctic and Antarctic sea ice from the aspects of the interactions and feedback processes between the polar atmosphere and ocean, the principal climate modes in mid- and high-latitudes, and tropical-polar teleconnections, and outlines the possible impacts of polar sea ice changes on both regional and global climate.