Human Transformation From Environmental Managers to Ecosystem Damagers
Beginning with Homo erectus at least a million years ago, hominins have used fire to engineer the world around them. The earliest uses of fire surely included cooking, changing the energy yields of foods. Such innovations altered the course of our evolution, facilitating the evolution of species that could adapt quickly using tools and social ingenuity. After 200,000 years ago, hominins also used fire to change the material properties of stone, pigments, sap, and wood. By at least 130,000 years ago, the impacts of this regular fire use are detectable in both Africa and Eurasia as vegetation changes that cannot be explained by changing climates alone. In southern-central Africa, changes wrought by early human fire use were so profound that there was significant transformation in erosion regimes. Although these changes represent a fundamental shift in the role of humans as dominant shapers of their environments, ecosystems adjusted as early humans remained embedded within them. Then, with the advent of agriculture and pastoralism in the Holocene, the strategy that had remained stable for at least 90,000 years began to unravel. With unprecedented speed, humans transformed themselves and the world around them through domestication and changes in land use, prioritizing survival of a few species over many. Although we built our ability to bend environments to our needs on millions of years of evolution and innovation, humans are not now simply shifting to another sustainable balance. Rather, we continue to push environmental thresholds across one tipping point after the next.