The story of the five farmers
The story of the five farmers

Here is a story which will help us to think about climate change.

There is a village, surrounded by five dairy farms. In the middle of the village, there is a big field called a common. It's called a common because it doesn't belong to anyone. Everyone can use it. The dairy farmers round about depend on the common, because it's full of grass, and their cows need to eat grass. Every day, the dairy farmers bring their cows to the common to graze (that is, eat grass). Each dairy farm has a herd of twenty cows. That makes a hundred cows, who spend all day every day eating grass. There's enough grass on the common for the hundred cows to eat their fill every day. The grass that's eaten is replaced by more grass regrowing. So the five farmers can look on contentedly at the peaceful scene as the hundred cows chomp on the green stuff, interrupted only by the occasional moo, fart or belch. The cows get on with each other, as cows usually do. So do the farmers. So far.

Why have the farmers got the cows? What's in it for them? What's in it for them is what's in the cows, that is, milk, which they take out of the cows every morning. (If you're a vegan, suspend your beliefs for a while to enter into the story.) They can then sell the milk, or make the milk into butter and cheese and sell that. That's how they make their living; that's how they support their families.

Then, one day, one of the farmers (let's call him Alan) decides he'd like to do a bit better for himself. He's just had another child (his fifth!) and he wants to move into a bigger house. That's going to cost more money. How will he pay for it? He can't make any of his existing cows produce more milk. So he goes to the market and buys five more cows. He has to pay for them, of course, but before long he's earned that money back in the income he receives from the extra milk production. Soon, his earnings are up by 25%. Lucky Alan! He and his family can move into their dream home. Of course, the extra cows need somewhere to eat grass. But that's not a problem. The common doesn't belong to anyone, so he doesn't have to pay to use it. There's no added cost in taking his extra cows to the common every day.

It's not long before the other farmers notice what Alan has done. Word gets round the village pub that Alan and his family have moved into a bigger house. What's more, he's got a new car, and his wife and kids have nice new clothes; he seems to have money to burn these days. What's his secret? Expanding his herd, that's what. The other farmers decide that they'd like some of what Alan's got. So, one by one, little by little, they head to the market and buy more cows. They produce more milk, more butter, more cheese. They earn more money. Now they can afford bigger houses, new cars, new clothes. They're spending more in the village shop and down at the village pub; good news for the shopkeeper and the publican, who themselves now have more money to spend. Prosperity all round; everyone's a winner.

Or are they? After a while, Alan and his fellow farmers notice that their cows are getting thinner and the milk yield is going down. Why? The answer is on the common. The grass there is getting thinner and thinner. There's less and less for the cows to eat. When there were just a hundred cows on it every day there was enough to go round. Now there are far more than a hundred, the grass is all used up and there's no time for it to regrow. If the farmers got rid of their extra cows, that would solve the problem; there'd be enough to go round again. But of course if they did get rid of the extra cows, their income would drop. They might have to move out of their big houses, give up their car, skip the fancy meals at the pub. So they keep their cows. And the grass keeps depleting. Eventually, there is none left. The common turns to dust and mud. The cows get sick and die of starvation. The farmers go bankrupt. So do the village shop and the village pub. The once prosperous village falls into poverty.

This story of the five farmers illustrates a problem: the problem of balancing individual benefit with the common good. If the farmers act on the basis of individual benefit, it makes sense for them to get as many cows as they can lay their hands on. The additional grass needed by the cows costs them nothing, and more cows means more prosperity for them. If, on the other hand, they act on the basis of the common good, they should restrict the number of cows they have, to stop the grass running out for everyone. But acting in the interests of the common good would mean sacrificing the greater prosperity that comes with having more cows. That's hard to do, when a bigger house and a new car and fancy meals down the pub (the publican's just hired a new chef) are right in front of you. Much easier to carry on buying cows. Easier until there's no grass left. By which time it's too late.

The obvious answer is for the farmers to sit down in the village pub together over a few beers and agree a limit on the number of cows they can each have. This will ensure that there are never more than a hundred in total and the grass never runs out. Let's imagine they do that. They start with a simple idea: we'll stick to twenty each. Then it gets complicated. Alan says hang on, I've got five kids to feed and house. Bernadette at the next farm is a single woman; she doesn't need as much as me. Can't I have more cows and she has fewer? Colin butts in and says, well my farm's been in my family since the twelfth century. My ancestors built the village church and fought at the Battle of Agincourt, so I'm entitled to more cows than anyone else. Denise pipes up to point out that she has a disabled son who needs expensive extra care, so she needs more income, therefore more cows. Eric (who's kept quiet till now) reminds them that he's the best at making cheese. Everyone wants to buy his cheese, because it tastes so good. He can't keep up with all the orders; he needs more cows to provide people with what they want. On they argue, late into the night, as the beer glasses mount up on the table.

They keep talking. After several evenings (and a lot of beer) they finally reach a compromise they are all happy with. In order to do this, they have had to make a number of trade offs, recognising that not everyone has the same needs or rights. Fortunately they have been able to make those trade offs in an amicable way. But that's not the end of it. What if one of them sneakily slips in a few more cows than their allowance? They realise that they're going to have to have a way of enforcing their agreement. Say they decide that anyone who wants to up their allowance of cows will have to do so by buying somebody else's cow off them, to avoid the common being overgrazed. Or say they agree that anyone who brings an extra cow one year, to up their income temporarily, will have to bring one fewer the next year to make up for it. Both these systems could work, but they require agreement, cooperation and trust, on an ongoing basis. They require the farmers to work collaboratively. For the common not to die, and for the cows not to die, and for them all to avoid falling into poverty, they will need to be willing to sacrifice some of their individual benefit. But nobody likes sacrifice.


What has all this got to do with climate change? You've probably worked it out already.


The grass on the common is the earth's atmosphere, the air that we all breathe, which can't be contained within borders or countries, which belongs to everybody and nobody. The cows are all the human activities - running factories, driving cars, flying planes, consuming stuff - that bring us prosperity but at the same time impact on the atmosphere by producing greenhouse gases. Before the industrial revolution, when human activity was low, the atmosphere was unaffected by greenhouse gases, so, like the grass before Alan went to market, the atmosphere remained stable. The increase in human activity in the last two hundred years is the farmers' spending spree on cows - it brings more prosperity, but it also damages what we all have in common: the grass / atmosphere. The farmers are all the countries in the world, who have to agree a fair way to stop what they all have in common - the grass / atmosphere - being so damaged that they will all fall into ruin. The evenings down the pub are the ongoing international negotiations on climate change, known as COP meetings. The farmers are the many governments of the world who are going to have to put the common good before individual benefit and, just as significantly, long term gains ahead of short term losses: the future ahead of the present.

The five farmers seem to have sorted out their grass problem. The global problem of climate change is a little more complicated, as we are dealing not with five people who all do the same job, live in the same place, and can sit round the same table in a pub, but with 192 countries and 7 billion people. And if we get it wrong, it won't just be a few cows who will die; the human race itself might be wiped out.

What are we going to do? Here are some questions to help us consider different solutions.

  • Is climate change the responsibility of individuals or of the state?
  • Is climate change better dealt with by markets or by regulation?
  • Should richer countries sacrifice more than poorer countries to deal with climate change?

We will be looking at some of these questions in future posts.