“How even this much water came to be on the Earth and whether any significant amount is trapped far beneath Earth’s surface remain topics of research.”
Ok, could this be where this is going? What happens to the water that is pumped several thousand feet down into a shale formation to force out the hydrocarbons trapped in the shale?
There’s a subterranean sea of sorts somewhere under the Himalayas (for one example); the amount of water pumped by humans — throughout history — doesn’t amount to much.