Abstract: In this study, coral records of sea-level changes as a proxy of past ice volume variations suggest that thesea-level rose up to -40/-50 m bpsl during the Penultimate Glacial period which is characterized by aseries of climatic instability, and constituted a high sea-stand at around ~177-168 ka BP. During the sametime interval, other proxy records of past climate (δ18O records of deep sea sediments, speleothems, pollenrecords, CO2, CH4, δD, dust records derived from Antarctic ice cores) show the enhancement of monsoonalactivity in tropical regions, occurance of an organic rich sapropel formation in the Mediterranean dueto the halt of the deep water formation, prevailing wet climatic conditions and the expansion of arboreal vegetation in mid-latitudes and decrease in the ice-volumes in polar regions. These sequence of eventspoint out that climatic instability in this time interval is driven by 65° N insolation. This in turn indicatesthat orbital parameters of the astronomical theory, the main driving forces of the climate and sea-levelchanges over glacial-interglacial time scales, are also a major forcing factor of the climatic instabilitybetween ~177-168 ka BP.