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

Summary

---

More or Less Podcast Summary

Episode: Does it take 15,000 litres of water to produce a kilogram of beef?
Host: Charlotte MacDonald (BBC Radio 4)
Date: May 2, 2026
Theme:
Charlotte MacDonald and expert guests critically evaluate the widely cited claim that a kilogram of beef requires over 15,000 litres of water to produce. The episode breaks down where this number comes from, what it really means, and how useful—or misleading—it is in debates about sustainable diets and environmental impact.

---

Key Discussion Points and Insights

Setting the Scene: Water Use and Online Disputes

• (02:03) Charlotte MacDonald introduces the fascination on social media with statistics about water use, especially regarding AI and beef.

  "If you spend much time on social media... you've probably come across a strange fascination with water consumption." — Charlotte MacDonald

• (03:03) Example from Twitter/X:

  "A kilogram of beef requires over 15,000 litres of water to produce. A vegan who uses ChatGPT every day is living a more sustainable lifestyle than someone who regularly eats beef while boycotting AI." — Social Media User

The Origin of the 15,000 Litre Claim

• (03:29) Charlotte introduces Dr. Mesfin Mikkonen, co-author of studies on water footprint, to explain what the number represents and its origins in academic research.

  "But the whole idea of the water footprint is we show the numbers, but behind the numbers there is the story." — Mesfin Mikkonen (03:29)

• The water footprint concept was intended as an awareness tool like carbon footprint, highlighting that water use impacts can be global, not just local.
  (04:06)

  "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 faraway places." — Mesfin Mikkonen

Virtual and “Footprint” Water Explained

• (04:36) Professor Mark Mulligan recounts how virtual water was conceived by Tony Allen in the early '90s:

  "So my late colleague... Tony Allen, came up with the concept of virtual water in the early 90s."

• Virtual water: the total water a crop or animal "uses" from growth to harvest or slaughter, including water evaporated through plant transpiration.

  "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..." — Mark Mulligan (05:06)

The Context of Water Use: Rainy vs. Dry Regions

• In dry places (e.g., the Middle East), irrigation water comes from valuable sources (rivers, groundwater), with real opportunity costs for other uses.
• In wet regions (e.g., Brazil), much of the water used is rainfall, and replacing rainforest with crops can result in a net decrease in water evapotranspiration.

  "If we have a cropland... in Brazil, ...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..." — Mark Mulligan (06:28)

Green, Blue, and Grey Water — What Do They Mean?

• (07:27) Tim Hess (Cranfield University) explains:
  • Green water: Rainfall absorbed by soil and used by plants.
  • Blue water: Water from rivers, lakes, aquifers (irrigation, piped, pumped).
  • Grey water: Water needed to dilute pollution from farming.

  "A differentiation was made between green water… differentiated from blue water. That's water in our water resources... there's a third category, grey water… to dilute any pollution, like fertiliser runoff." — Tim Hess (07:33)

What Does the 15,000-Litre Figure Actually Include?

• Most of the water in the 15,000 figure is used to grow feed for cows.

• In countries like the UK, grass-fed cattle are mostly "eating rain" (green water), not competing with other water uses.

  "In the UK, cows mostly stand around in fields eating grass. That grass gets its water from rainfall." — Charlotte MacDonald (08:15)

• Only a small portion is blue water, and this can vary drastically; in the UK, about 67 litres of blue water per kg of beef, while in arid regions of the US, blue water can be up to 8,000 litres per kg.

  "In the UK... about 67 litres per kg of beef of blue water consumption. ...from the US... ranging from through to almost 8,000." — Tim Hess (08:49)

Why the Number is (Mostly) Misleading

• The 15,000-litre global average:

  • Includes all water types and all farming systems.
  • 94% of this is green water (rain),
  • Only about 500 litres per kg, on average, is blue water (but this varies a lot by region and method).

• Using the global water footprint makes beef look environmentally disastrous, but this doesn’t reflect real impacts—especially in rain-rich areas.

  "We shouldn't be including the green water. That's very misleading." — Tim Hess (09:48)

• Averaging blue water over all systems hides local impacts. The real worry in sustainability is blue water use in water-stressed regions—not rainfall in the UK.

  "You can't use the global water footprint to say that beef is bad." — Charlotte MacDonald (10:01)

Scientist Reactions to the Number’s Use

• Mesfin Mikkonen expresses regret over how the numbers, originally meant for awareness, are misunderstood and misused.

  "There is a disappointment of the misuse of numbers that's clear. And the disappointment also goes back to myself. Where did I do my job very well and explain the numbers and the story behind them." — Mesfin Mikkonen (10:31)

---

Notable Quotes & Memorable Moments

• Mesfin Mikkonen (03:29):

  "Behind the numbers there is the story."

• Mark Mulligan (06:28):

  "The water footprint of the coffee crop is actually negative because the forest is gone."

• Tim Hess (09:48):

  "If we want to make choices about sustainable diets... we shouldn't be including the green water. That's very misleading."

• Mesfin Mikkonen (10:31):

  "There is a disappointment of the misuse of numbers that's clear."

---

Key Timestamps

| Timestamp | Segment/Insight | |-----------|--------------------------------------------------------------------------------------------| | 02:03 | Host introduces the water use debate and the 15,000-litre claim. | | 03:29 | Mesfin Mikkonen explains the original intent behind water footprint numbers. | | 04:36 | Mark Mulligan contextualizes the concept of virtual water and its real-world significance. | | 06:28 | Discussion of water usage in wet vs. dry regions. | | 07:27 | Tim Hess explains green, blue, and grey water. | | 08:49 | Examples of blue water use in the UK vs. US. | | 09:48 | Why including green water in sustainability comparisons is misleading. | | 10:31 | Mesfin Mikkonen reflects on the misuse and communication of these statistics. |

---

Conclusion

While “15,000 litres of water per kilogram of beef” is technically accurate as a broad, global average, this statistic is largely meaningless for assessing environmental impact. Most of that water is just rainfall on fields and would have fallen anyway. The real concern is blue water use—particularly in water-scarce regions—which varies tremendously depending on cattle feed sources and regional farming practices. Using nuanced and location-specific data is essential when debating sustainable diets or policy, rather than leaning on the dramatic but misleading global averages that tend to dominate social media arguments.

Transcript

[Advertisement Voice]

This BBC podcast is supported by ads outside the uk.

[LinkedIn Ads Narrator]

Ever invest in something that seemed incredible at first but didn't live up to the hype? Like those $5 roses at a gas station? Or a secondhand piece of technology that breaks in the first 10 minutes? Marketers know that feeling. We optimize for the numbers that look great, impressions reach and reacts. But when they don't show revenue, well, that's a not so great conversation with the CFO. LinkedIn has a word for bullspend. Now you can invest in what looks good to your CFO. LinkedIn Ads generates the highest roas of all major ad networks. You'll reach the right buyers because you can target by company, industry, job title, and more. So cut the bull. Spend. Advertise on LinkedIn, the network that works for you. Spend $250 on your first campaign on LinkedIn ads and get a 250 credit for the next one. Just go to LinkedIn.com broadcast that's LinkedIn.com broadcast. Terms and conditions apply.

[Kohler Ambassador]

When Kohler, global design leader in luxurious kitchen and bath products, asked me to be their ambassador for timeless, elegant, durable cast iron, I said, I'm in. Soon after, I was in their Kohler, Wisconsin foundry watching molten iron poured, enamel applied by hand, and the beautiful finished pieces ready to ship. Since 1883, Kohler cast iron has been crafted by incredible artisans, and seeing it firsthand gave me a whole new appreciation for their craftsmanship. Now I'm proud to lend my stamp of approval to my favorite Kohler cast iron products for their durability, beauty and enduring style. Shop my curated [e-mail] as the Kohler Cast Iron Ambassador, I say Long live Cast Iron.

[Charlotte MacDonald]

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 MacDonald. 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 programs 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 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 eating beef. Here's an example from Twitter or X.

[Social Media User]

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

[Charlotte MacDonald]

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

[Mesfin Mikkonen]

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.

[Charlotte MacDonald]

This is Mesfin Mikkonen, 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 Arjun Hoekstra and a Dutch professor who pioneered the idea of the water footprint.

[Mesfin Mikkonen]

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 faraway places.

[Charlotte MacDonald]

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.

[Mark Mulligan]

So I'm Professor Mark Mulligan and I'm professor of Physical and Environmental Geography at King's College London. So my late colleague at King's College London, Tony Allen, came up with the concept of virtual water in the early 90s.

[Charlotte MacDonald]

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.

[Mark Mulligan]

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.

[Charlotte MacDonald]

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.

[Mark Mulligan]

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.

[Charlotte MacDonald]

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 Arjun 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 dry lands where there's little to no rain.

[Mark Mulligan]

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.

[Charlotte MacDonald]

In this case, if you think a higher water footprint is a bad thing, then you'd be saying that chopping down rainforest for coffee plantations is good. What's more, the water we're talking about falls as rain. And to put it mildly, rain is not in short supply in a rainforest.

[Advertisement Voice]

When the concept of water footprint was first developed, it was recognised that not all water is the same.

[Charlotte MacDonald]

This is Tim Hess, a professor of water and food systems at Cranfield University in the uk.

[Advertisement Voice]

And a differentiation was made between green water that has come from rainfall, differentiated from blue water. That's water in our water resources, whether it's rivers, lakes, whether it's water that is underground in our aquifers.

[Charlotte MacDonald]

Green water is rain, blue water is pumped out of rivers and lakes. There's a third category, grey water, which is the water that's needed to dilute any pollution, like fertiliser runoff. Right back to the beef. If we look at beef production and this 15,000 figure, the majority of the

[Advertisement Voice]

water is associated with producing feed. It takes a lot of feed to keep those animals alive for two years before they go into the food system.

[Charlotte MacDonald]

In the uk, cows mostly stand around in fields eating grass. That grass gets its water from rainfall,

[Advertisement Voice]

so they are just using the rain at the point where the rain falls and they are only using green water. But in other countries, we have systems where animals are fed on crops which have been irrigated. So in that case, we're taking the blue water to grow the crops, like maize silage, and then feeding those to animals.

[Charlotte MacDonald]

The different methods of farming make a massive difference to the amount of blue water you have to pump out of rivers, lakes and aquifers to produce the cow food.

[Advertisement Voice]

So in the UK, we have an average for animal production of about 67 litres per kg of beef of blue water consumption. But there are some figures that are from the US from Texas, Oklahoma, Kansas, ranging from through to almost 8,000.

[Charlotte MacDonald]

That figure we're looking at, that 15,000 litres of water are needed for each kilogram of beef, includes all types of farming and all the types of water. It's a weighted average of the water use across all the different beef production systems the researchers analyzed. And 94% of that figure, more than 14,000 litres of water, is green water. It's rain falling on grassland or other crops. This, says Tim, makes it pretty useless if you're using the number to think about how good or bad eating beef is for the environment. As with coffee in the rainforest, it's unclear whether it's a good or bad thing.

[Advertisement Voice]

So if we want to make choices about sustainable diets, we want to make choices about is this product having more impact on the water environment than that product, then we shouldn't be including the green water. That's very misleading.

[Charlotte MacDonald]

At the same time, the 15,000 litre claim also averages out the blue water part, which, as Tim said earlier, can range from less than 100 litres to many thousands. The average is about 500 litres. But that hides the bit that potentially matters most in terms of the impact on water supplies. All of which means you can't use the global water footprint to say that beef is bad. And when Mesfin sees his numbers used like that, it makes him uncomfortable.

[Mesfin Mikkonen]

There is a disappointment of the misuse of numbers that's clear. And the disappointment also goes back to myself. Where did I do my job very well and explain the numbers and the story behind them.

[Charlotte MacDonald]

That's it for this week. Thanks to Mes Van Meeken, Mark Mulligan and Tim Hess. If you've seen a number you think we should take a look at, email us on moreorlessbc.co.uk until next time. Goodbye.

[Grainger Advertisement Voice]

When you manage procurement for multiple facilities, every order matters. But when it's for a hospital system, they matter even more. Grainger gets it and knows there's no time for managing multiple suppliers and no room for shipping delays. That's why Grainger offers millions of products in fast, dependable delivery, so you can keep your facility stocked, safe and running smoothly. Call 1-800-GRAINGER, click grainger.com or just stop by Grainger for the ones who get it done.

[Road Safety PSA Narrator]

I drive my bus in a busy city. That's why road safety is so important to me. I know that I must slow down and be extra careful when I make a wide turn. Buses need more room than cars. Everyone can help keep our roads safe. Next time you're driving. Remember to give buses plenty of time and space to finish turning before driving ahead. Let's all plan to share the road safely. Learn how at www.sharetherodesafely.gov.