The Last Glacial Cycle

During the past 2 million years Earth ice sheet’s have been continuously growing – covering considerable parts of North America, Europe and Asia – and shrinking. At the maximum of the last glaciation about 21,000 years ago, when large quantities of water were stored in these ice sheets, global sea level was approximately 120 m (394 ft) lower than today. Surface temperatures in many regions of the Earth were significantly colder. This animation shows the extent and height of the continental ice sheets as well as the distribution of land and ocean that is altered by changes in sea level.
A truly satisfactory explanation of the dynamics of glacial cycles remains elusive to this day. There is compelling evidence that changes in the strength and distribution of solar insolation caused by variations in the Earth's orbit around the sun (see below) are mainly responsible for the build-up and melting of ice-sheets. However, the way in which these variations interact with e.g. atmospheric circulation, ocean currents and the terrestrial and marine biosphere is still being investigated.

Download animated gif file
Download SOS/MP tar file