| Summary: | The climate of the nine interglacials of the past 800,000 years has been simulated with both snapshot and transient experiments using the model LOVECLIM in response to changes in insolation and CO2 concentration. These simulations allow to investigate the relative contributions of insolation and CO2 to the intensity and duration of each interglacial as well as the differences between the interglacials at global and regional scales. The transient simulations which cover a full range of precession, obliquity and eccentricity allow to investigate the response of different climate variables and different latitudes to astronomical parameters. The results show that the relative contribution of insolation and CO2 on the warmth intensity varies from one interglacial to another. They also show that CO2 plays a dominant role on the variations of the global annual mean temperature and the southern high latitude temperature and sea ice, whereas, insolation plays a dominant role on the variations of monsoon precipitation, vegetation and of the northern high latitude temperature and sea ice. The model results show that obliquity and precession have different weight on temperature and precipitation of different latitudes. The response of the climate system is shown to depend strongly upon the phase between obliquity and precession. Based on these simulations, an OPE (obliquity-precession-eccentricity) index is developed to estimate the climate sensitivity to astronomical forcing. The model results suggest that caution should be taken when astronomically tuning the chronology of a proxy record or tuning it to a proxy from other regions. Finally, the past interglacials are compared to the Holocene and the near future natural climate, which allows looking for the best interglacial analogue for the whole Holocene and its natural future.
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