If all the ice melted it would raise the oceans by something like 230 feet, so modern Vienna would still be above water at 495 – 1778 ft elevation.
Although some estimates suggest Earth loses 20 - 30 cubic kilometres of water to space annually. Plus whatever water is bound up in mineralisation annually.
450 million cubic kilometres of water lost over a 15 million year period would lower ocean by something like … a bit?
The total volume of water on Earth is presently estimated to be around the 1.386 billion cubic kilometre mark.
The volume of a sphere increases to the cube of its radius … carry the 1 … nup, that’s to hard for me.