NASA | Mars' Ancient Ocean

NASA researchers have provided the most accurate estimate of Mars' water history, revealing that at least 20% of the Martian surface was once covered by an ocean with a depth of about one mile. Over billions of years, nearly 90% of this water was lost to space, with the rest trapped in the polar caps. This new understanding suggests Mars was much wetter than previously thought, increasing the likelihood of ancient habitability.

How does the new picture of early Mars compare to previous isotopic estimates regarding its wetness?

What implications does the presence of water on Mars have for its ancient habitability?