Evidence Shows Early Humans Used Fire to Shape Earth’s Ecosystems 50,000 Years Ago

A groundbreaking study published in the Proceedings of the National Academy of Sciences reveals that early humans were using fire to modify their environments as far back as 50,000 years ago, a timeline that predates previous estimates by about 10,000 years. This research, led by Dr. Debo Zhao from the Institute of Oceanology at the Chinese Academy of Sciences, presents new evidence found in a 300,000-year-old sediment core from the East China Sea, which contained fossilized charcoal remnants known as pyrogenic carbon. These particles indicate a significant increase in fire activity correlating with the migration patterns of Homo sapiens across Eurasia, Southeast Asia, and into Australia.

Historically, it was believed that human influence on geological processes began during the last Ice Age, around 12,000 years ago. However, Dr. Zhao's team found a marked spike in pyrogenic carbon levels approximately 50,000 years ago, which does not align with known climate patterns of the time, suggesting a new factor at play—intentional human fire use. According to Dr. Zhao, “Our findings challenge the widely held belief that humans only began influencing geological processes in the recent past.” This assertion is backed by archaeological evidence showing a rapid expansion of Homo sapiens during this period, which coincides with increased fire activity, indicative of systematic landscape modification rather than natural occurrences.

Dr. Stefanie Kaboth-Bahr, a paleontologist at Freie Universität Berlin and co-author of the study, elaborates on the implications of this early fire use, stating, “Humans likely began shaping ecosystems and the global carbon cycle through their use of fire even before the Last Ice Age.” The repeated use of fire for various purposes—cooking, warmth, and land management—resulted in substantial ecological changes, contributing to the alteration of carbon fluxes in the atmosphere.

The research further indicates that these early fire practices had lasting impacts on ecosystems. As Professor Wan Shiming, another co-author, notes, “Even during the Last Glaciation, the use of fire had probably started to reshape ecosystems and carbon fluxes.” This revelation is significant as it suggests that humans were fundamentally altering the Earth’s carbon cycle tens of thousands of years earlier than previously thought, challenging the notion of the Anthropocene epoch, which is often associated with agriculture or industrialization.

The researchers compared their findings with data from other regions, including Europe, Southeast Asia, and Papua New Guinea-Australia. The same patterns of increased fire activity were observed, indicating a widespread human influence on the environment during this period. This phenomenon, referred to by some scientists as the 'pyroscape', represents the enduring legacy of fire through time.

This study is part of a broader initiative, known as The Burning Question, which seeks to understand the role of fire in shaping ecosystems over the last 600,000 years. Supported by the German Research Foundation and various partners in Ethiopia, the project aims to explore fire’s ecological, climatic, and cultural significance across different regions.

The implications of these findings are profound, as they not only reshape our understanding of early human behavior but also highlight the long-standing relationship between humans and their environment. As the planet faces significant climate challenges today, revisiting the historical context of human interaction with fire may provide valuable insights into sustainable practices and ecological stewardship for the future.