A groundbreaking study from Stanford University is reshaping scientific understanding of how rivers formed and functioned in Earth’s distant past. The research, published this week in Science, challenges decades of textbook teaching by demonstrating that meandering rivers—long thought to be impossible without plant life to stabilize their banks—actually existed hundreds of millions of years before vegetation colonized the land.
For much of modern geological history, scientists assumed that before about 500 million years ago, when plants first began spreading across terrestrial landscapes, rivers were primarily braided. These types of rivers are characterized by multiple shallow channels weaving around sandbars, lacking the stability and sinuous patterns seen in modern meandering rivers. According to prevailing thought, only after roots and vegetation began to bind soil together could rivers develop the single, curving channels associated with meandering systems.
The new Stanford-led study upends that view. Researchers analyzed high-resolution satellite imagery of approximately 4,500 bends from 49 rivers worldwide. Importantly, about half of those rivers flowed through landscapes with little to no vegetation. The team found that in these unvegetated environments, river bends still migrated and deposited sediment in a manner identical to vegetated, meandering rivers. Point bars—the crescent-shaped accumulations of sediment on the inner bends of rivers—formed even in the absence of roots.
Lead author Dr. Taylor Perron, a geoscientist at Stanford, explained that the findings reveal the mechanics of meandering do not depend solely on plants. Instead, fluid dynamics and sediment transport alone can produce the same curving, migrating structures that geologists previously attributed to vegetation. “Our results show that meandering rivers are not a byproduct of plants, but rather an intrinsic behavior of flowing water and sediment,” Perron noted in the study.
The implications of this discovery extend well beyond river morphology. Meandering rivers are known to create broad floodplains, which act as major long-term reservoirs for carbon storage. If meandering rivers were present hundreds of millions of years earlier than previously believed, this means Earth’s carbon cycle—and consequently its climate—may have functioned differently than models have long assumed. Ancient meandering systems could have sequestered significant amounts of carbon, moderating climate in ways not previously accounted for in reconstructions of the planet’s early atmosphere.
Dr. Anne Gold, a climate scientist not involved in the study, emphasized the importance of the findings for climate modeling. “If we are revising the timeline of when large-scale floodplains developed, that means our estimates of carbon burial and release in Earth’s early history need to be adjusted. This study offers a crucial correction to the baseline assumptions we use in deep-time climate models.”
The study also provides fresh insights into how landscapes evolve under different planetary conditions. The researchers suggest that understanding the intrinsic ability of rivers to meander without vegetation could inform the search for past water activity on other planets, such as Mars, where evidence of ancient river channels persists but vegetation was never present. By establishing that meandering is not tied to plants, scientists may gain new tools for interpreting extraterrestrial river deposits.
This reinterpretation is part of a growing trend in Earth sciences that reexamines long-held assumptions about the interplay between life, water, and climate. For decades, the prevailing narrative tightly linked the spread of terrestrial vegetation with the stabilization of landscapes and the development of new river types. By decoupling those events, the Stanford study reframes how geologists and climatologists view the co-evolution of Earth’s surface environments and its biosphere.
The research also underscores the critical role of advanced observation techniques. Using modern satellite imaging to capture thousands of river bends across the globe allowed researchers to assemble a dataset far larger and more diverse than traditional field studies could provide. This expansive approach gave the team confidence that the patterns they observed were not isolated anomalies, but a fundamental property of river systems.
As the findings ripple through the scientific community, geologists anticipate that textbook explanations of early Earth landscapes will need significant revision. The recognition that meandering rivers thrived before the emergence of terrestrial plants not only alters the narrative of Earth’s geological past but also forces scientists to rethink the links between landforms, ecosystems, and climate stability across deep time.
By revealing that the planet’s rivers were far more dynamic than previously believed, the Stanford study highlights the importance of river morphology in Earth’s long-term carbon storage. In doing so, it provides a more nuanced baseline for understanding climate patterns both in the distant past and in projections of the planet’s future.
