What does the sheer volume of ancient water required to carve large features suggest about the early Martian climate?

Answer

It suggests the early climate was much warmer, perhaps sustained by greenhouse gases

The immense scale of features like outflow valleys necessitates a large volume of liquid water, which requires significantly warmer conditions than the current environment provides, possibly maintained by atmospheric greenhouse gases that have since been lost.

What does the sheer volume of ancient water required to carve large features suggest about the early Martian climate?
MarsGeologywaterevidencehypothesis