Exploitable results Global ice sheets during the 2 climatic cycles, with a special emphasis on entering into glaciation How the climatic system and, in particular, the global ice sheets, have responded to change in the incoming solar radiation over the last 250 000 years has been studied, with a special emphasis on the glacial inceptions which started roughly 238 000 and 122 000 years ago. Long-term variations of some fundamental climate variables from ice core proxy records over two climatic cycles and how the climate has entered into glaciation after the peak of isotopic stages about 122,000 and 238,000 years ago were reconstructed and simulated, respectively. The work has contributed to a better understanding of the fundamental physical processes governing climatic and environmental changes and therefore helped to assess the impacts of human activities on climate over the next century. By providing data over a wide range of climate states over which climate models can be validated, the past is expected to help predict to future. The extended Vostok ice core record showed great similarity between the previous and the last climatic cycles. The temperature interpretation of water isotopes in ice cores was examined by simulating the isotope cycles in general circulation models (GCM). Two complementary approaches were used for modelling the ice sheets: one based upon field observations and the other upon the dynamical equations of the ice flow and ice physics. Experiments have shown that a fine resolution is necessary to simulate reasonably good snow accumulation and temperature over Antarctica. A similar high resolution is also particularly important for the model resolving the mid-latitude depressions which is vital for the correct simulation of European climate. Coupling models clearly shows the importance of properly modelling the interactions between the land-surface and the atmosphere. The long-term interactions between the atmosphere, the ocean, the ice sheets, the lithosphere and the carbon cycle have been studied through coupled climate models. The ocean circulation, the distribution of all tracers, the carbonate deposition in deep-sea sediments are reasonably well simulated. Using a hierarchy of climate models helped to identify linear and non-linear aspects within the climate system. Searching for OpenAIRE data... There was an error trying to search data from OpenAIRE No results available
