Over the past decade, the availability of new low-frequency microwave spaceborne data has provided key parameters of the cryosphere and polar ocean that can be assimilated into Earth System Models, enhancing our understanding of fundamental processes. Among these parameters, the most significant are sea ice thickness in the lower range, sea surface salinity, soil state, and more recently, ice sheet temperature, subsurface snow melt, and the presence of aquifers. Building on these findings, new initiatives have emerged to explore the potential of using even lower frequencies (with the current lower limit being 1.4 GHz). These lower frequencies can penetrate deeper into ice and have shown greater sensitivity to sea surface salinity in cold waters. Airborne surveys conducted in Greenland and Antarctica have demonstrated the potential of low-frequency wideband radiometers in monitoring polar regions, offering unprecedented capabilities compared to existing and planned spaceborne satellites. Today, mission proposals are being developed in both the U.S. and Europe. Notably, ESA recently approved the CryoRad mission for Phase-0 studies as a potential candidate for Earth Explorer 12. CryoRad aims to address critical observational gaps through an innovative ultra-wideband 0.4–2 GHz radiometer, designed to provide groundbreaking products. The three main mission objectives are: (i) Better assess the mass balance and stability of ice sheets and ice shelves, by bridging the observation gap for ice sheet/shelf temperature profiles; (ii) Better assess the freshwater cycle and water mass formation at high latitudes, by bridging the observation gap for sea surface salinity in cold waters; (iii) Investigate sea ice dynamics and salinity exchange processes in the Arctic and Antarctic, by bridging the observation gap for sea ice salinity and 0.5-1 m sea ice thickness. The aim of the proposed session is to present the mission concept to the scientific community, discuss the methodologies for extracting geophysical parameters, and evaluate the potential impact of these new parameters on Earth System Models. Achieving this will require strong collaboration with the modeling community across various domains: oceanography and ecosystems for sea surface salinity and sea ice, glaciology and Earth system science for ice sheets and ice shelf parameters. Additionally, the climate and atmospheric communities can also contribute, given the interconnectedness of the different systems.