What exactly is fossil water? And why have we consumed so much of it?

No, it’s not a new brand of bottled water, imported from the days of dinosaurs.

Fossil water came from melting ice sheets, ancient lake systems, and a generally wetter climate tens to hundreds of thousands of years ago.

It percolated into porous rocks, which were then buried under deep layers of sediment, where it was sealed off from the surface, and there it stayed.

Until farmers discovered it. And in the second half of the 20th century, they started drilling wells into fossil aquifers and pumping like mad, turning sunny dry places into acres and acres of green farmland.

Crop supplies boomed. Food became cheaper and more plentiful, grown in formerly parched places like California and Kansas and shipped around the world for people like you and me to eat, ingesting fossil water with it.

The trouble is, fossil water is a finite resource, and new studies suggest that many fossil aquifers may become depleted this century, so that we won’t be able to rely on them any longer.

This could mean that the crops that depend on them could become less plentiful and more expensive again.

All the while, population will likely increase. The climate will likely warm. Our demand for water will continue to climb.

Which means we’ll have to adapt to the lack of fossil water just as we adapted to its discovery. This time with more efficient crops and farming methods—and more efficient use.