Remember having to learn those Coleridge lines by rote as a kid? Turns out, the “not a drop to drink” bit is coming true — and not just for the ancient mariner.

In the intro to her Freshwater project on this site, Arati Kumar-Rao pointed out that if all the freshwater (groundwater, rivers, lakes, wells, all sources of water we can actually drink) were to be frozen, the resulting cube would be just about the size of Bangalore.

The bit that should make us weep? That cube, pitifully small when we consider the number of thirsty humans, and cattle, and wildlife, plus all the other demands we place on our water sources, is shrinking at a dramatic rate. Like, so:

Twenty-one of the world’s 37 largest aquifers are losing water at a greater rate than they’re being refilled, falling victim to population growth and climate change. Thirteen of those diminishing water sources are experiencing “significant distress,” including the Arabian Aquifer System, which supplies Saudi Arabia, Syria, Iraq, and Yemen, the Murzuk-Djado Basin in northern Africa, the Indus Basin of India and Pakistan, and the Central Valley Aquifer System in California.

That clip is from a Vice News report that cites a joint NASA-UC Irvine study.

“It’s very serious,” Jay Famiglietti — who judged by the evidence appears to be a master of understatement — of NASA’s Jet Propulsion Laboratory and an author of the report, tells Vice. The story, which speaks of what can ramify as various regions run out of water, is scary in the extreme.

Here, read: The World Is Running Out of Water