Oil, Fertilizer, and the Green Revolution

In the early 1900s, two German chemists, Fritz Haber and Carl Bosch, figured out how to pull nitrogen straight out of the air and combine it with hydrogen to make ammonia. Nitrogen is the nutrient that limits plant growth more than any other, and until then farmers depended on manure, compost, or nitrogen-fixing crops to get it into soil. The Haber-Bosch process made nitrogen fertilizer cheap and industrial, produced by the ton rather than the wagonload. That fertilizer alone would have raised yields some, but it also tended to make tall wheat and rice plants grow so heavy with grain that they fell over before harvest, a problem called lodging.

Plant breeders solved that in the mid-1900s by crossbreeding in genes for short, stiff stalks. Agronomist Norman Borlaug led this work on wheat in Mexico, and similar breeding happened on rice in the Philippines. These short-stalked varieties put their energy into grain instead of height, stood up under the weight of heavy fertilizer-fed harvests, and responded to irrigation far better than traditional varieties. Fertilizer, new seeds, and irrigation worked as a package: each one amplified what the others could do, and together they are what people mean by the Green Revolution.

The results reshaped the food-population math of the twentieth century. In the 1960s, demographers like Paul Ehrlich predicted mass famine as population outran food supply. Instead, countries that adopted the new seeds and fertilizer, India chief among them, saw grain harvests surge, feeding billions more people without a proportional increase in farmland. But the inputs that made this possible cost money, which connects this topic to globalization's uneven benefits: nations and farmers with capital, credit, and access to irrigation gained the most, while the environmental costs of decades of heavy fertilizer and groundwater pumping became their own long-term problem.