Sheep (and wool and land and etc.)

Regularly questions and discussions arise about wool and sheep [1]. Is it effective and/or useful, is it better/worse than alternatives, and so forth. Time to delve into that and try to put it into perspective.

First, let’s look at some numbers: There are approximately 800.000 sheep in the Netherlands, producing 2 million kilograms of wool, around 2,5 kilograms per sheep [2][3]. If you use that as insulation material, it weighs at least about 20 kg/m3 (up to 100 for felt). For a house, let’s say you need 100 m2 at 20 cm thick, that’s about 400 kg per house, enough for roughly 5000 row houses per year. Maximum. That’s not really making a big difference. It’s better then to knit wool sweaters: 1 wool sweater requires about 1.2 kg of wool, so roughly 1.8 million sweaters per year. With 18 million Dutch people, that would be one sweater per person every 10 years. Assuming that’s also the pace at which sweaters wear out, then all sheep could provide each of us with a sweater permanently. Moreover, if they last a bit longer, perhaps there’s even room for woolen underwear. Then we wouldn’t even need to insulate our houses in an increasingly warmer country. That’s a bit exaggerated, but in emergencies (no more fossil fuels), it works, as our ancestors knew.

Okay. But then, the land use for that wool, for insulation or per sweater, is that interesting or could it be better? About 1 hectare of grazing land is needed for 10 sheep [2]. That hectare then yields about 20 to 25 kg of wool per hectare, or about 10 sweaters per year per hectare (ignoring processing and labor-land), or about 6 m2 of insulation per year. How does that compare to other natural materials? Take flax for example. The yield of flax ranges between 6,500 and 8,000 kilograms per hectare with a high fiber percentage between 23 and 25 percent [4]. Roughly, that’s 2000 kilograms of fiber per hectare, which is somewhere between 75 to 100 times more than a sheep-hectare. Again, disregarding all additional factors in both cases, as a rough comparison, this suffices. Flax insulation weighs about 27 kg/m3. So, per hectare, you can produce 74 m3 of insulation, enough for 370 m2 of insulation, compared to 6 m2 from sheep. Per hectare.

In short, if you keep a sheep for wool, it has one of the lowest yields per hectare of all possible products. No wonder, because you’re making fibers via an unnecessarily long route: the fiber can grow directly in the field instead of going through the ‘sheep mill’ first. Every step creates losses. And there simply isn’t enough land to produce wool via sheep to provide, for example, insulation. When it comes to wool, there are other fibers that yield much more. All this still under the condition that sheep are shorn; I read that in some regions, it’s more expensive than what the wool yields. But well, that’s money again, and that’s not a good guide, that’s not a measure of nature or environment or climate or biodiversity. It’s a self-invented unit. We here only look at the growth and regrowth of the natural/ecological/physical system and what’s practical.

The question that also arises regularly is whether all that sheep’s wool has to come from the Netherlands; in the Middle East, they have plenty of sheep, right? That’s correct, but that’s causing those lands to desertify, that is, those parts that weren’t so already. Remember that agriculture began there, it was called the ‘fertile crescent.’ There’s not much left of that. Partly because of the sheep that have eaten everything bare, and on top of that: a lot of water is also needed for wool processing. Together, this has contributed to desertification. And it’s so bad that villages are already disappearing entirely due to sandstorms; people however still hold on to sheep herding, not least for internationally sought-after Persian carpets. In other words, ‘we get it from afar’ is a disastrous approach, as with most of our stuff.

We limit ourselves to the Netherlands, which happens to have little space or land, 10 times less per capita than the world average. But then comes the following remark regularly: Yes, but you can’t entirely attribute the impact of wool to the sheep. The sheep is already there. So is it a bycatch? Perhaps, but then the relevant question is what is the impact of the sheep without wool? Should it even be there, that sheep? What is it there for? On the island Texel, they’re mainly there for cheese and lambmeat because, as I observed earlier, shearing is too expensive. When it comes to meat and milk, a sheep is by no means the first choice in terms of land use. Besides, we need to move towards much less meat and dairy solely due to the enormous burden on land and the environment caused by animal breeding.

Alright, we won’t do that. No meat and dairy, and as long as we still have some sheep wandering around here, we’ll just put on that extra sweater: made of wool. But why are those sheep wandering around anyway? Time to delve into that.

To graze and pasture’, as it’s called. That’s a considerable area. Sheep are regularly moved to graze, but if you add everything together, at 10 sheep per hectare, about 80,000 hectares of grazing land is needed for those 800,000 sheep. They are mainly on heathland (moor land?), of which there is about 40,000 hectares in the Netherlands. And additionally, mostly on dyke bodies. Let’s say they need about 40,000 hectares of dikes, combined (accumulated over time). There’s much more dyke [8] but it’s not permanently grazed.

Regarding that heathland part, one of the main arguments for sheep is: Sheep keep the heathland healthy. But what’s the advantage of grazing the heath? Why is that necessary? What if they don’t do that anymore? We read: “If we do nothing, the heath will grow dense. Other plants grow faster and taller due to the enormous increase in nutrients (read: animal manure as fertlizer), leaving no chance for the heath. And then biodiversity, the variety of plant and animal species, will decrease even further.” [9]

Okay, but the problem is not that the heath is disappearing, but that there are too many nutrients added via animal manure. And that’s all related to the livestock industry. So if we reduce the livestock and avoid nitrogen, the heath remains intact, and the sheep are no longer needed to maintain the heath. So there’s no need for a sheep from a grazing perspective. It’s a matter of priorities and not just filling one hole with another.

Moreover, where did that heath come from? “A heath landscape was created by people: the land was used to let sheep and cows graze. Heath turfs were cut to use, for example, in the cattle shed. Sand, gravel, and peat were also extracted. Hundreds of years of grazing, cutting, and burning resulted in a heath landscape full of biodiversity and cultural history.” [10]

In other words, it originated from human activity, not natural processes. Unless you consider humans to be a natural process, but then the disappearance of the heath is also natural (just like in that case climate change, by the way…). And there’s no need to desperately combat the disappearance of that heath with sheep, Sheep, which are also partly responsible for it themselves.

Let’s allow forests to grow instead, right? Because young birch trees are popping up everywhere between the heath. “If you let them be, a birch forest will soon grow here and the heath will disappear.” That’s the same boreal forest that covers immense parts of Russia and plays an essential role in the climate and CO2 system (CO2 storage). And indeed, we need more forests as one of the most effective methods to mitigate the climate crisis.

So it’s a bit strange: first creating heath through overgrazing, which then gets threatened because the livestock industry becomes industrialized (manure) , and then breeding sheep to graze it again and prevent it from reverting to its original state. The wool is also irrelevant; what remains is the meat. But we also know that we need to largely say goodbye to our meat diet. Which would then allow the heath to naturally persist.

Strange world.

What remains: sheep as lawnmowers on dikes. Perhaps we could have done something useful with that grass if it were just mowed and collected, but oh well. It does look nice, a sheep on a dike, instead of the modern alternative: robot lawnmowers. But let’s limit sheep to dikes then? With the bonus of some meat, cheese, and a few woolen sweaters as byproducts.

Sheep are cute and useful, if you have a lot of space, a lot, like 500-3000 years ago. And yes, 1 sheep or 1 sweater isn’t a disaster. But they are absolutely unnecessary (as a ‘means of production’) when, as in the Netherlands, we have to turn over every square meter three times before allocating it to either agriculture, livestock farming, solar parks, construction, water storage, or biobased materials production. And all of that needs to become organic produced too, because otherwise, the soil will be depleted, and everything will turn into heath…. Which we then want to maintain, of course. Exactly, with sheep. But then we all have enough sweaters. That’s for sure.

[1] general information scheep (dutch) WUR:

[2] own information from sheep sheperds

[3] rtl news (dutch):

[4] Flax yield and fiber :


[5] desertification


[6] CBS (dutch)

[7] cattle in New Zealand, mainly sheep, is reasonable for 90% of all methane emissions of the country.

[8] grazing on dikes , more background

Netherlands has 17.786 km dikes :


[9] foundation ‘natuurmonumenten’: (dutch)

[10] governmental forest management (Staatsbosbeheer) (dutch)

Author: ronald rovers