Does it take 15,000 litres of water to produce a kilogram of beef?
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What is the fascination with water consumption on social media?
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Hello and thanks for downloading the More or Less podcast.
We're the program that looks at the numbers in the news, in life and in beef. I'm Charlotte McDonald. 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 the platforms like X, Blue Sky 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 pastime, eating beef.
Here's an example from Twitter, or X. Ignoring the AI part, is that true?
Does it really take 15,000 litres of water to produce a kilogram of beef?
Does it actually take 15,000 litres of water to produce a kilogram of beef?
When the number comes in, people see that's easy to just take numbers and talk about. Beef is so bad and others are so good. But the whole idea of the water footprint is we show the numbers, but behind the numbers, there is the story.
This is Mesvin Meekanen, an assistant professor at the University of Alabama, and he definitely knows what this 15,000 number means. It features in scientific papers from the early 2010s that he co-wrote with Arjen Hoekstra, a Dutch professor who pioneered the idea of the water footprint.
The initial motivation was to create awareness similar to the carbon footprint and the land footprint to create awareness that our water impact is not located only where we live but it's far away places also.
The issue is that the water footprint is being used to say that the amount of water beef uses is bad. And the story explaining what's wrong with that goes back to before the water footprint was developed.
So I'm Professor Mark Mulligan, and I'm Professor of Physical and Environmental Geography at King's College London.
What is the concept of virtual water and how does it relate to beef production?
So my late colleague at King's College London, Tony Allen, came up with the concept of virtual water in the early 90s.
Quick botany lesson. As they grow, plants absorb water from the soil through their roots. This is sucked up through the plant to the leaves where it evaporates. It's a process called transpiration.
So Tony's concept for virtual water is that when a crop grows or when an animal like a cow eats a crop that's growing, they... consume, if you like, all of the water that that crop had to evaporate over its lifetime in order to produce the biomass that is the crop.
This might sound a bit technical, but for the work Tony Allen was doing, the importance of the water required to grow plants was pretty obvious.
He developed the concept for drylands in the Middle East. In that context, when you're growing a crop, you're usually growing it with irrigation water from groundwater and rivers.
How does the water footprint differ between various farming practices?
In very dry places, water is a precious resource. The water you use for irrigation is water you can't use for something else, like drinking or sanitation. This water has a clear environmental cost. The idea of virtual water was taken on by Arjen Hoekstra and expanded. He developed a method for figuring out how much water a food crop or animal used, wherever it was in the world. But to point out the obvious, not all parts of the world are arid drylands where there's little to no rain.
So, for example, if we have a cropland that is growing coffee, let's say, in Brazil, well, that probably replaced forests that was there before in that kind of humid, wet environment. And indeed, the forest would have consumed through evaporation more water than the coffee crop does. So in that case, the water footprint of the coffee crop is actually negative. Because the forest is gone, you actually have more water than you would have had if the forest was there.
What role does green water play in beef production?
In this case, if you think a higher water footprint is a bad thing, then you'd be saying that chopping down rainforests for coffee plantations is good.
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Chapters
7 chapters
1
What is the fascination with water consumption on social media?
0:00–2:11
2
Does it really take 15,000 litres of water to produce a kilogram of beef?
2:11–3:32
3
What is the concept of virtual water and how does it relate to beef production?
3:32–4:42
4
How does the water footprint differ between various farming practices?
4:42–5:53
5
What role does green water play in beef production?
5:53–6:52
6
How do environmental factors influence the water footprint of different crops?
6:52–7:57
7
Why is the 15,000 litre claim potentially misleading for sustainable diet choices?
7:57–10:39