Polar climate change and variability arise from complex interactions among Earth system components, and may have far-reaching impacts on lower-latitude weather extremes and global climate. This session aims to synthesize current understanding of the mechanisms and consequences of polar climate change and variability across a range of spatiotemporal scales. Contributions are invited that explore: (1) the roles of atmospheric, oceanic, sea-ice, land processes, along with local and remote forcings and feedbacks in shaping polar climate; (2) the influence of high-impact weather processes (e.g., atmospheric rivers and extratropical cyclones) and internal variability on polar climate and its predictability; and (3) Arctic and Antarctic climate changes and their interactions with weather extremes and climate variability at lower-latitudes. Studies based on observations, theory, simulations across model hierarchies, and machine-learning approaches are encouraged. This session will provide insights for ongoing coordinated modeling efforts, including the CMIP7 and the next phase of Polar Amplification MIP.