Role of the ice cover in climate changes.

Present global warming had been preceeded by a four century long cool period, the Little Ice Age. It was triggered by a long term volcanic activity, the present climate change is believed to be a result of human activity: emission of carbon-dioxide and other greenhouse gases. Ice cover played an important role both in cooling and warming processes. The role of ice, that is not properly taken into account in the current climate models, will be analysed in this paper. [ABSTRACT FROM AUTHOR]