Apologies double didn’t realize the double asterisks would screw up the formatting. 1.4 trillion trillion cubic meters ocean volume. 4 trillion cubic meters fresh water consumption

Assuming:
Current ocean salinity = 35 kg / m3. Current ocean volume = 1.4 * 1018 m3. Current human fresh water usage = 4 * 109 m**3.

(35 * 1.4 * 1018) / (1.4 * 1018 - 4 * 10**9).

= 35.0000001 kg / m**3. = New ocean salinity.

I think they’ll be okay.