• Introduction
• A historical perspective
• Greenhouse gas emissions and fertilizer production
• GHGs and fertilizer use
• Non-fertilizer initiatives

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A historical perspective

Before the 20th century, limited supplies of plant-available nutrients were a major factor holding back agricultural production and slowing population growth. In the 19th century, two figures stand out as the founders of modern fertilization. In England, J.B. Lawes created the world’s first fertilizer factory to produce superphosphate and established an agricultural research station that still carries on some of the original experiments started in 1843. In Germany, Justus von Liebig studied the importance of minerals and atmospheric nitrogen to nourish plants, resulting in his famous Law of the Minimum, which states that a deficiency in any growth-limiting factor (nutrients as well as water, light, etc.) will impair plant development.

Unlike other nutrients, mineral sources of nitrogen for fertilization have been rare and largely unavailable on a global scale. For this reason, nitrogen remained the single most important limiting factor for crop production and stable food supplies until well into the 20th century. In 1909, Fritz Haber discovered how to synthesize ammonia from air under high pressure and temperatures, which led him to receive the 1918 Nobel Prize in Chemistry. Carl Bosch subsequently made the breakthroughs necessary to bring the process to an industrial scale, thus ushering in the modern nitrogen fertilizer industry. In 1931, Bosch was the Nobel Chemistry Laureate for this accomplishment. Industrial nitrogen fixation is the only achievement to date to be recognized by two separate Nobel Prizes.

Following the privations of World War II, many countries made food security a top priority. In the following years, policies were put in place to encourage farmers to use fertilizers and other modern farming technologies. Fertilizer consumption grew rapidly, largely in parallel with an accelerating expansion of the world population.

It has been estimated that some 40 per cent of the protein consumed by humans depends on the Haber-Bosch process. (1) More than 99 per cent of all nitrogen fertilizers are derived from ammonia, which is both an intermediate and a final product. The vast majority of the energy consumed by the fertilizer industry is used for ammonia synthesis (some 94%).

^{1 Smil, V. (2001). Enriching the Earth: Fritz Haber, Carl Bosch, and the Transformation of World Food Production. MIT Press: Cambridge, Massachusetts, USA and London, England.}