The general consensus is that the temperature of the earth's atmosphere is rising. During the course of the last century, the average global surface temperature rose by about 0.6°C. 1998 proved to be the warmest year since systematic meteorological measurements began in 1861, and scientists are now predicting that average global temperatures will rise by between 1 and 6°C over the next 100 years.

How rising temperatures will affect the ice around the poles is difficult to estimate. Reports of a decreasing amount of sea ice in the Arctic Ocean are mainly based on local observations and satellite observations of the sea ice. Scientists do not rule out the possibility that part of the ice has not vanished but has partly been redistributed by ocean currents and winds.

These dynamic forces play a very important role in the distribution of sea ice, especially if it is thinning and prevailing winds get an even better grip on it. By setting out satellite beacons, the expedition helps to monitor the wind forces. Wind direction and speed can be reconstructed, based on barometric pressure. The exact movement of the ice is tracked by interval GPS readings.

Imagine that in some parts, sea currents and winds are opening up the ice, creating open water leads. These open leads freeze up again if it is cold enough, and they are a source of newly formed sea ice. In other parts, sea ice gets compressed and it piles up to pressure ridges with high "sails" and "keels".

Pressure ridges acount for 30 to 80% of the volume of sea ice, depending on the amount of deformation. So it is very well possible that huge volumes of sea ice have accumulated in different parts of the Arctic Ocean. This is exactly what ESA's CryoSat mission is able to point out: the precise volume and distribution of sea ice over a multi-year period. It will determine rates of ice thickness change and consequently improve our understanding of the relationship between the earth's ice cover and global climate.