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The Quiet Hero: Fritz Haber and the Fertiliser Revolution

Almost one in two people alive today owe their continued existence to the findings of a German chemist, Fritz Haber.

Hyperbole? Perhaps not. In 1909 Haber invented the first method to produce synthetic (inorganic) fertilisers on an industrial scale. The Haber-Bosch process synthesises ammonia from nitrogen and hydrogen gases in the atmosphere; the oxidation of ammonia creates components necessary for the production of nitrate fertiliser.

This scalable process to harvest ammonia dramatically increased the availability of fertiliser for farmers. Fertiliser use has led to an explosion in crop yields and enabled the earth to feed an additional two to three billion people. Importantly, while population has more than doubled since 1950, average land devoted to agriculture has increased considerably less so. In fact, had agricultural yields remained their levels in 1900, feeding the world in the year 2000 would have required nearly four times more cultivated land, or nearly half of all ice-free continents.

This intensification of agriculture helped sustain a deep trend of structural transformation. Advanced economies, which were in by-gone times mired in agricultural subsistence, were now able to continue their shift towards manufacturing and service-driven economies without sacrificing – or worrying about – agricultural output. Unlike Malthus, Adam Smith celebrated the benefits of population growth: more people meant greater specialisation and larger possibilities for the division of labour. Incomes soared. Population has grown exponentially, as predicted by Malthus – but, in thanks to agricultural intensification, so too have our means of subsistence.

Malthus Redux: Diminishing Returns and Ecological Crisis

Using fertiliser is picking low-hanging fruit. While its deployment has been far from unanimous – many parts of sub-Saharan Africa still do not use synthetic fertilisers – it, like many productive technologies, suffers from diminishing returns. Typically farmers apply a carefully-measured mixture of nitrate and phosphate fertilisers two or three times per growing season to provide essential plant nutrients. Beyond these recommended dosages, additional use has little benefit for yields. What it does do, however, is damage the environment.

The production of fertiliser requires large volumes of natural gas, contributing to greenhouse gas emissions. Fertiliser runoff caused by excessive or improper application can pollute water sources and damage the ecological environment. Over time, continual use degrades soil fertility. These externalities have little bearing for poor farmers who are dependent on their harvests for current income. Those who do use fertiliser may over-apply in hopes of striking a record harvest. Largely, their efforts will be in vain, and as is often the case, will come at the long-run cost of others. Developing a mechanism facilitating the transfer of fertiliser from excessive users to non-users would be improving for all, but remains difficult.

Do We Need a Haber 2.0?

Fritz Haber gave us a half-century of breathing-space in the early 20th century. It only took until 1968 for Paul Ehrlich to heed the next Malthusian call of a global ‘population bomb’ at our doorstep. Once again, the bomb was defused; unprecedented efforts to reduce fertility levels, extraordinary advances in agricultural practices and technology, and a widespread opening-up of international markets countered the growing pressure. This time around, the world was fed by breakthroughs in the breeding of high-yielding and resilient crop varieties, ushering in a new ‘Green Revolution’ for the world in the late 1960s and early 1970s. For most, incomes kept soaring; consumption - and waistlines - continued to grow.

Nature Geoscience

The situation, today, is again sombre. Combined economic, demographic, and now also ecological pressures are once more threatening global food security. At a time when investments into agricultural innovation and technology are stagnant or declining, is blind faith in an imminent Haber 2.0 rational? Demand for food is expected to increase upwards of 70% by mid-century. With the sun having set on the Haber honeymoon, a new series of technologies and market mechanisms will be needed to ensure global demand is met.

First, subsidies and other barriers which distort or prevent an optimal distribution of food resources should be removed. In many developed societies, the price of food is far too cheap; prices should internalise the externalities of agriculture, one of the largest sectors contributing to global greenhouse gas emissions. Second, the transfer of technology and spread of best practices in agriculture to poor areas, particularly in Africa, will be needed. The widespread mechanisation of agriculture in Europe and North America offers a blueprint for these developing countries, but many technologies will have to be appropriately adapted - machines that get stuck in the mud are of no use. Lastly, greater public and private investments into newer crop varieties, including drought-resistant strains, flood-tolerant strains, and C4 rice (with enhanced photosynthesis) will desperately be needed.

Is Haber 2.0 close by, or far away? Malthus may have been proved wrong, but his spirit remains. R&D and mechanisms facilitating the better transfer of resources and technologies have the potential to defuse today’s bomb, but they are by no means a guarantee.


Erisman, J.W., Sutton M.A., Galloway, J., Klimont, Z., and Winiwarter, W., "How a century of ammonia synthesis changed the world", Nature Geoscience 1, 636-639, 2008.

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