Insolation and sea level variations during Quaternary interglacial periods: A review of recent results with special emphasis on the last interglaciation

During the last million years, interglacial periods were characterized by sea level, Antarctic air temperature and atmospheric CO2 concentrations different from those of today. The relationship between CO2 and climate remained rather constant over these intervals, which confirms that CO2 acts as a positive feedback to insolation forcing. The thermohaline circulation and the Atlantic meridional overturning are sources of another strong positive feedback mechanism. They have been responsible for the partial melting of the West Antarctic Ice Sheet during the last interglaciation and for the amplification of the insolation forcing to trigger the last glacial inception.