The last interglacial period (LIG)—the Eemian—is commonly believed by scientists to have been warmer than the current Holocene interglacial.
Along with that balmier climate there is evidence that sea levels were significantly higher than today. Previous studies have pegged Eemian sea levels at 4 to 6m higher than today. Recently, a new investigation raises that estimate, reporting that ancient sea levels peaked between 6.6 and 9.4 m (~20 to 30 feet). Modern day accounts of flooding in low lying coastal areas and tropical islands abound, with ominous suggestions of links to global warming. How high the oceans will rise is a topic of debate for IPCC members, the news media and assorted climate alarmists, but they are asking the wrong question. Instead, they should ask why are sea levels so low?
Wiki has an interesting read in the “Marine Terrace” article, including a chart of Global Sea Level fluctuations over the lasy 500 million years
en.wikipedia.org/wiki/File:Phanerozoic_Sea_Level.png
indicating that sea levels have nearly *always* been higher than the current level.