From an altitude of just over 700 km and reaching latitudes of 88°, CryoSat-2 is monitoring precise changes in the thickness of the polar ice sheets and floating sea ice. The observations made over the three-year lifetime of the mission will provide conclusive evidence of rates at which ice cover may be diminishing.It is now generally agreed that the Earth's atmosphere is getting warmer, and although the impact of climate change is expected to be amplified at the poles, it is extremely difficult to predict what effect this is having on the polar ice cover.