The Colonial Footprint

Before muskets were fired and flags were planted, Europeans had already made their impact on the Americas in the form of a cough, a sneeze, or even a handshake. Within a century of “first contact” with Europeans in 1492, when Columbus famously landed in the Bahamas, most of the Indigenous population had been wiped out by disease. Trees sprang up, crops returned to the wilderness, and native flora overtook abandoned settlements as those who had so carefully maintained the forest were now gone. However, this regrowth was only the beginning. In the absence of native stewardship, Europeans imposed new systems and foreign species, which degraded both American ecosystems and human relationships with them. Colonization didn’t just change the course of history—it also reshaped the land, polluted the environment, and introduced foreign species and agricultural systems that continue to impact the continent today. The environmental footprint left by European settlement is as deep as its political one. 

When Europeans first arrived in the Americas, Indigenous populations were estimated at about 10 million. 62 million hectares, or about 10 percent of America’s land, had been under human use for agriculture, settlements, and forest management. Over the next century, as Old World diseases such as smallpox, influenza, and measles spread throughout the continent, nearly 95 percent of the native population perished. With such a large population decline, indigenous land-management practices declined, with no one to put them into use. Without these practices—such as controlled burns—natural vegetation grew back over abandoned areas, sequestering about 7.4 petagrams of carbon from the atmosphere. This resulted in a drop in atmospheric carbon dioxide of seven to 10 parts per million (ppm) between 1520 and 1610 that can be seen in Antarctic ice core records. This carbon dioxide decline is believed to have contributed to a global cooling event occurring around that time known as the Little Ice Age, where temperatures dropped by as much as two degrees Celsius. While other factors like volcanic activity spurred this effect, the massive sequestration of carbon dioxide by forest regrowth is thought to have played a role in global cooling during that time period. 

The introduction of old-world species like horses also had lasting ecological consequences. While Native American tribes like the Comanche incorporated horses into their cultures, large herds of wild horses resulting from runaways disrupted the flora. Their hooves compacted soil, damaged riparian zones or vegetated transition areas between the land and bodies of water, and disrupted the natural grazing patterns of native species like bison. Trampling of stream banks and preferential horse travel paths increased runoff and decreased soil infiltration, preventing native plants from regrowing and resulting in desertification, a process of degradation that causes fertile land to become arid and unable to support growth. This contributed to the environmental degradation of biomes such as grasslands and prairies, especially in areas of Mexico and the American Southwest. 

European agricultural practices also contributed to soil depletion and erosion. Monoculture, plowing, and the establishment of large plantations for commercial farming were a sharp contrast to indigenous methods such as polyculture and shifting cultivation, which prioritized soil health. Using measurements of Beryllium-10 in river sediment, researchers found that erosion on the eastern seaboard of North America increased after European colonization at a rate of almost 100 times the natural speed. This massive soil loss altered river systems by increasing the turbidity, or haziness, of the water due to suspended particles; fragmenting habitats by making them smaller and less connected; and degrading conditions for fish and other organisms. The scale of this erosion meant that rivers would need centuries to empty themselves of the resulting sediment, disrupting natural cycles in a phenomenon known as legacy sedimentation. 

Another major environmental cost of colonization came from the exploitation of mineral resources, especially gold and silver. The Spanish Empire’s use of the “patio process,” which mixed crushed silver ore with mercury, salt, and copper sulfate, enabled heat extraction of pure silver. The mixture was spread over a courtyard or patio. As mules were driven over it for long periods of time, chemical reactions occurred, freeing the silver. Then, the remaining alloy could be heated to release pure silver. Though highly effective, this method of production came at a great ecological and human cost. The mercury waste was often released into the atmosphere or dumped into waterways, especially at Potosí, Bolivia, and Huancavelica, Peru—two of the largest mining hubs. Between 1564 and 1810, about 17,000 metric tons of mercury were released into the atmosphere. Long-term mercury concentrations exceeded the EPA safety reference levels by a factor of 30 to 100. Through modern soil sampling, researchers have found that the mercury concentrations in present-day Huancavelica range from 1.75 to 698 mg/kg, meaning that the population of Huancavelica continues to be exposed to legacy mercury runoff contamination. They are currently at high risk of developing health complications, including nervous system deterioration, neurological disorders, kidney and digestive damage, and motor dysfunction. 

These cases collectively depict the alarming decline of environmental stewardship after colonization. Environmental stewardship is the philosophy and practice of responsibly managing the environment and its resources for the benefit of future generations. The Native Americans, having lived in harmony with nature, had harbored a deep respect for the world around them and had integrated sustainable practices into daily life. Besides controlled burns to prevent wildfires and promote new growth, many tribes practiced selective hunting and fishing to ensure the survival of a population, crop rotation, and the cultivation of the “Three Sisters” (corn, beans, and squash) in symbiotic planting systems. Conversely, the Europeans, having come to this continent for profit, did not share the same sentiment. Through colonization, land and resources were commodified, turned into products for economic gain rather than managed for the future of ecosystems. This change from stewardship to exploitation degraded the environment and disrupted the spiritual relationships that Indigenous peoples had with the land. By looking into America’s history of colonization and the origin of neglectful practices, we encourage confrontation and understanding of environmental degradation. Only then can we begin to heal our relationship with the land we depend so much on.