Does it take 15,000 litres of water to produce a kilogram of beef?

If you spend much time on social media, and we don’t necessarily recommend it, then you’ve probably come across a strange fascination with water consumption.

Mainly, this is people telling you that using AI is terrible for the planet because of how much water it uses. We’ve already made a couple of programmes about the numbers in those arguments and, long story short, they probably aren’t saying what you think they’re saying.

But on platforms like X, BlueSky, and TikTok, an opportunity to keep an argument going is rarely missed

And one of the numbers that’s been enlisted in that glorious cause concerns the water that’s used for a seemingly unrelated past-time - eating beef. Here’s an example from a user on X:

“A kilogram of beef requires over 15,000 litres of water to produce,” they wrote. “A vegan who uses ChatGPT every day is living a more sustainable lifestyle than someone who regularly eats beef while boycotting AI.”

Ignoring the AI part, is that true? Does it actually take 15,000 litres of water to produce a kilogram of beef?

It turns out that the number isn’t wrong, but it probably isn’t saying what you think it’s saying.

If you’ve seen a number you think we should take a look at, email the More or Less team: moreorless@bbc.co.uk

CONTRIBUTORS:

Mesfin Mekonnen, Assistant Professor at the University of Alabama

Mark Mulligan, Professor of Physical and Environmental Geography at King's College London

Tim Hess, Professor of Water and Food Systems at Cranfield University

CREDITS:

Presenter: Charlotte McDonald

Producer: Mhairi MacKenzie

Series producer: Tom Colls

Production co-ordinator: Brenda Brown

Sound mix: Emma Harth

Editor: Richard Vadon