Polar regions play an essential role in the complex climate system. They are characterized by very low temperatures, marked seasonality, huge continental ice sheets and large oceanic areas permanently or seasonally covered by sea ice. Despite recent advances in the understanding of polar ice sheets, the sign of their current evolution is still not known. Interferometric SAR proved to be a powerful tool to investigate the changes in the cryosphere at the required high accuracy. Suitable interferometric data are mainly available in C- Band and were acquired in 1994 during ERS-1 Ice Phase (3 day reapeat pass), the ERS-1/2 Tandem Mission (1995-1999) and the Radarsat Antarctic Mapping Mission (September/October 1997, 24 day repeat pass). At present, no compareable systems are available.This contribution compares the potential of various systems for the monitoring of the polar but also global land ice dynamics. L-Band SAR is preferred for single satellite missions because of the longer decorrelation time. Higher accuracy for both ice motion and surface elevation is achieved by X-Band because of the shorter wavelength and lower penetration depth. A two satellite X-Band SAR mission is described, which was proposed in the frame of a call for a national german earth explorer mission (ICEDANCE - Ice Mass Transport and Balance of Glaciers and Ice Sheets). The aim is to measure the ice motion and surface height of key regions of the global land ice masses and their temporal and spatial variability with an emphasis of the polar ice sheets in Antarctica and Greenland, areas around the poles included.In a close formation flight the measurement of digital elevation models (DEM Mode) and in several hours separated formation flight (Motion Mode) the measurement of surface displacement both in unprecedented accuracy is possible. Beside the primary objective, which is to quantify the contribution of polar ice sheets to sea level change, ICEDANCE has the capability to fulfil several secondary mission objectives such as the measurement of river run off and the demonstration of a series of new SAR modes. Examples for the applications are presented.