Antarctica InSync Scientific Theme 3: Antarctic ice sheets and ice shelves: Processes driving rapid change, from observation to prediction [white paper]

Rapid and accelerating changes across the Antarctic Ice Sheet are driven by coupled ice–ocean–atmosphere–solid Earth processes. This impacts sea-level change, ocean circulation and climate feedbacks, all of which remain insufficiently understood. Despite major advances in observations and modelling, critical uncertainties persist regarding ice-shelf stability, ice–ocean heat exchange, basal melt, surface melt and mass accumulation variability, and the influence of bedrock motion and subglacial hydrology on ice dynamics. This white paper identifies four major Knowledge Gaps (KG) that must be addressed to improve predictions of the future evolution of the Antarctic Ice Sheet (AIS). Here, we outline the methodological advances, Key Variables (KV) and coordinated observing strategies – including the development of observational super-sites – needed to close these gaps. Antarctica InSync offers a unique opportunity to implement and test these approaches ahead of International Polar Year-5 (IPY-5), providing the foundation for sustained long-term observations of key Antarctic regions. The proposed recommendations strengthen links between process understanding, sustained observations and model development to improve knowledge of AIS interactions with the ocean, atmosphere and solid Earth, along with its projected contribution to global sea-level change in a warming climate.