Napkin math says about 343km^3/year of water to contend with, and the Panama canal work took 35 years to move about 0.2km^3 of earth, about 0.006km^3/year. As

Napkin math says about 343km^3/year of water to contend with, and the Panama canal work took 35 years to move about 0.2km^3 of earth, about 0.006km^3/year. As a layperson it seems to me you'd need to channel a vast area already below sea level (3500km^2 at ~100m deep?) to put a dent in the rise. Again, napkin math. Reuters claims "75.6 trillion gallons of water added to the ocean each year" and a Panama canal history page says the French dug 30M cubic yards and the Americans dug 238M.