There Was a Time When Poop Powered the Economies of Half the World. This Is the Rise and Fall of Guano

Throughout history, humanity has pursued various resources. The gold rush is a prime example of how obsession with a particular resource can drive people to madness, plundering everything in sight without considering long-term consequences. This makes sense when it comes to gold, but did you know something similar happened with seabird droppings?

This is the story of guano, the “white gold” that transformed the Peruvian economy—for better or worse.

White gold. Friedrich Wilhelm Heinrich Alexander von Humboldt had a lot of time on his hands. Born in 1769, the German philosopher, scientist, geographer, naturalist and explorer traveled to South America in 1802. During his visit to the Peruvian coast, he noticed how locals used a white substance to enrich their soil. It was guano, the dried excrement of seabirds.

While walking through an area with large guano deposits, he reportedly began sneezing uncontrollably. His curiosity led him to send samples to Europe for study. What happened next was predictable: Pre-Columbian civilizations had used guano for generations, but Europeans, recognizing its value as an excellent fertilizer, soon took a keen interest.

Fertilizer. Guano is compost. Its very name, “wánu,” means “compost” in Quechua, and its unique composition makes it a powerful soil enhancer. The conditions of the Peruvian and Chilean islands, including their dry climate, the composition of the rocks and the seabirds’ marine diet, created a compound rich in nitrogen, phosphorus, calcium and potassium.

It was ideal for improving soil fertility and boosting crop yields. European and American farmers quickly recognized its potential. The reason? A growing population had led to overexploited fields, depleted soil and widespread crop failures. A miracle solution was needed, and guano seemed to be it.

A poop mine. Peru and Chile rushed to exploit the resource. Between 1840 and 1880, demand for guano exploded, and the Peruvian islands became one of the world’s most prized economic assets. The U.S. and European nations loaded dozens of ships with this “white gold,” and Peru reaped the rewards. In just 40 years, the country exported about 11 million tons of guano, generating an estimated $38 million in revenue.

That figure may seem modest today, but at the time, guano transformed Peru’s economy. The revenue funded ports, railroads and roads. In the first year of guano exploitation, it accounted for 5% of the country’s income. By the last decade of the boom, that number had skyrocketed to 80%.

The “guano war.” The frenzy reached such heights that, in 1856, the U.S. passed the Guano Islands Act, allowing any American citizen to claim uninhabited islands with guano deposits. This led to the private seizure of around 100 islands in the Pacific and Caribbean. But things escalated further between 1879 and 1884.

The War of the Pacific—often called the “Guano War”—erupted between Peru, Chile and Bolivia over control of the richest guano and saltpeter deposits. Chile emerged victorious, annexing key territories, including the Atacama Desert, now a hub for renewable energy production.

Ironically, just years before, these same nations had allied against Spain in another conflict where control of guano played a major role.

Collapse and crisis. Peru became so reliant on guano exports that when the boom ended in the late 19th century, an economic crisis followed. Demand for guano didn’t disappear overnight, but two key factors led buyers to look elsewhere. First, reserves began to dwindle, and production could no longer meet demand.

Second, synthetic fertilizers emerged as a cheaper, more efficient alternative. Unlike guano, they didn’t need to be shipped thousands of miles on risky voyages. Peru learned a hard lesson: No economy can depend solely on one resource. Diversification became essential to avoid future crises.

Guano today. Guano remains an excellent fertilizer, and it isn’t just produced by seabirds. Bat guano also boasts remarkable fertilizing properties, and excrement from seals and penguins holds similar value. However, it remains an expensive commodity, especially as wildlife populations decline.

In the end, guano played a crucial role in modernizing agriculture and advancing fertilizer technology. When natural supplies ran low, artificial fertilizers stepped in to fill the gap. The cycle repeated itself.

It also served as yet another example of how Latin American resources were exploited for the benefit of foreign powers. European nations extracted guano using local labor under conditions akin to slavery, reaping the rewards while leaving little behind.

History repeats itself. It’s impossible not to draw parallels with today’s rare earth elements. Most production is concentrated in a single country—China—while the West scrambles for alternative sources. The U.S. has its eye on Ukraine and Greenland precisely because of their rare earth elements deposits.

Beyond the economic impact, the indiscriminate “harvesting” of guano led to the colonization of remote islands, disrupting ecosystems. The loss of guano devastated species dependent on it, affecting fish, bacteria, fungi and invertebrates.

Today, conservation efforts consider ecological balance when collecting guano and other natural resources. But during the peak of exploitation, environmental concerns were the last thing on anyone’s mind.

Images | Clemens v. Vogelsang | shankar s.

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