Is the world approaching 'peak fertilizer'?

After decades of steeply rising consumption, global fertilizer use has levelled off.

Synthetic fertilizers have allowed us to feed the world. Around half of humanity relies on them. 

They’re not only important for food production and nutrition, but they’re important for the environment too. We’ve seen massive increases in crop yields – partly due to fertilizers – and this means we need less farmland. Less farmland means less deforestation and more space for wildlife.

But there is an environmental cost to using fertilizers too, especially when we overapply them. Not all of the nitrogen, phosphorous, or potassium that we put on the crops is used by them. The rest runs off into rivers, lakes, and other waterways and becomes a pollutant. The ‘dead zone’ in the Gulf of Mexico is caused by excess nutrients.

This means two things: we want farmers to have fertilizers to use when they need them. We don’t want fertilizer use to be zero. But we also want to use them efficiently: the fewer inputs we need to get a good yield, the better.

The global population is still growing, and the world is producing more food. People might assume that the use of fertilizers is still rising steeply.

But look at the data and we see that the rise in global fertilizer use has slowed dramatically, and in the last five years it has essentially flattened out. This is shown in the chart below.

It’s too early to call – fertilizer use might continue to creep up – but the world could be approaching ‘peak fertilizer’, despite producing more food and feeding more people.

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Fertilizer use is falling in many countries

Fertilizer use is still growing rapidly in many countries. But global growth is slowing because it’s falling in others.

Most rich countries have either reached a plateau or have managed to reduce fertilizer use over the last few decades. See some examples in the chart below.

In the United States, consumption has barely changed since the 1970s. Across Europe, it has fallen significantly. In the Netherlands and Sweden, it has more than halved. In the UK and France, it has fallen by more than a third. Fertilizer use might have peaked in China, too.

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Efficiency gains mean that many countries have decoupled fertilizer use from production

This has not come at the cost of crop production. Output in many countries has continued to increase while fertilizer use declined.

We see this in the chart below, which plots the change in fertilizer use and crop production (measured in tonnes) compared to 1961.¹ This decoupling is more pronounced in Europe than in the US. The UK produces 84% more than in 1961 but uses the same amount of fertilizer. Crop output in the Netherlands has more than doubled, and fertilizer use is actually 20% lower than in 1961.

We don’t see this same change in China because fertilizer use rose steeply through the second half of the 20th century. Its decoupling came later. But if we look at the change since 2010, China’s crop output increased by 25% while it used the same quantity of fertilizer.

This decoupling has been possible because we used fertilizer so inefficiently in the past. Most of the nutrients we applied to crops weren’t actually used by them. As I wrote about in detail here, it’s possible to reduce fertilizer use without sacrificing food production by adopting better farming practices.

This does not mean eliminating fertilizer use, it means using it better.

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Many countries need more fertilizer, not less

We want to reduce fertilizer use where we overapply it. But I want to stress that zero-fertilizer is not the target. In fact, many countries need more fertilizer, not less.

In the world’s poorest countries, farmers use hardly any at all. In the chart, we can see how fertilizer use per person stacks up across countries. Low-income countries use around 10 times less per person than countries in Europe.

Such low application rates come at the cost of crop yields and food production. Yields of staple crops across most countries in Sub-Saharan Africa have remained stubbornly low: they have increased a bit, but not much. And they lag far behind other regions.

This is bad for the planet – it means more and more land needs to be used for farming. And it’s bad for farmers: they get little return for their crops. As I wrote in a separate article, improving agricultural productivity across Sub-Saharan Africa is one of the most important problems we face this century. To do this, the region will need a lot more fertilizer.

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1. What this metric doesn’t take account of is the changing composition of crops. We’re just looking at total output, measured in tonnes. But this wouldn’t tell us whether countries were making big shifts from fertilizer-heavy crops to ones that need less fertilizer.

I admit that this aggregate measure is imperfect, but I think the story would be similar for most countries if we corrected for crop composition and nutritional output. The world is not only producing more crops in tonnage terms, but it’s also producing more calories and protein than ever before too.