Scientists Just Reconstructed 540 Million Years of Earth’s Sea Level History and Reached a Concerning Conclusion
Story by Jessica Bennett
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Earth and Planetary Science Letters (2025). DOI: 10.1016/j.epsl.2025.119526 | The Daily Galaxy --Great Discoveries Channel© Daily Galaxy US
Recent research conducted by an international team of scientists from Utrecht University, the UK, and the US has resulted in a significant advancement in the understanding of sea level changes. Published in Earth and Planetary Science Letters, this study has reconstructed sea level variations over the past 540 million years in unprecedented detail. This breakthrough allows scientists to analyze rapid fluctuations in sea levels on a thousand-year timescale, providing new insights into Earth’s evolution, subsurface structure, and applications in green energy and environmental management.
Sea level fluctuations have always been tied to two primary factors: plate tectonics and the amount of land ice present. By studying fossil records and sedimentary layers, researchers have previously reconstructed long-term sea level trends on timescales of millions of years. However, the ability to measure these fluctuations on much shorter, thousand-year intervals was not possible until now. This new approach enables scientists to quantify changes in sea level with much greater precision, shedding light on smaller-scale variations that were previously undetectable.
The Impact of Plate Tectonics and Ice on Sea Level VariationsPlate tectonics and land ice are the two dominant forces driving sea level fluctuations. Earth’s tectonic activity determines the depth and configuration of ocean basins, while the presence of ice sheets dictates how much water is stored on land, which directly impacts sea levels. As Dr. Douwe van der Meer, the lead author of the study, points out, “In time steps of about a million years, you can derive an average sea level for as far back as there are fossils, about 540 million years.” This means that the study not only covers periods of extreme sea level change but also offers insight into how the Earth’s landscape and climate have evolved over vast timescales.
However, long-term variations are not the sole focus of the study. The new research demonstrates that sea levels did not simply fluctuate over millions of years but also underwent rapid shifts on much shorter timescales. “We suspected that sea level could go up and down enormously in much shorter periods as well, but there is not enough data to make those shorter time steps,” explains Dr. Van der Meer. By investigating shorter intervals and using sedimentary evidence, scientists can better understand these rapid variations and their relationship with global climate patterns.
Unveiling the Rhythmic Wobble of Earth’s Axis and Its Effect on Sea LevelsThe Earth’s axial tilt and its wobble have profound implications for climate patterns and, consequently, for sea level fluctuations. During cold periods when ice sheets form on the poles, Earth’s axial wobble influences the timing and intensity of ice ages, which last tens of thousands of years. “We see alternations, especially when the global climate is cold, and there is ice on the poles. Then, the rhythmic wobbling of Earth’s spin axis creates ice ages that last only tens of thousands of years, during which the sea level can go up and down by as much as 100 meters,” says Dr. Van der Meer.
These cyclical variations provide critical data on how Earth’s climate has interacted with the distribution of ice, directly influencing sea levels. The ability to measure these oscillations of sea level on a much smaller timescale helps to clarify the overall trend of rising and falling water levels throughout geological history. It also provides valuable data for understanding the geological record and offers insights into how Earth’s systems will respond to current and future climate changes.
A New Era in Sea Level Research: Creating Layer Maps of Earth’s SubsurfaceOne of the key applications of understanding past sea level changes is their relevance to geological research, particularly in mapping Earth’s subsurface. The knowledge gained from the recent study allows scientists to develop more accurate maps of the Earth’s subsurface, which is vital for various practical purposes such as energy resource management, underground CO2 storage, and safe waste disposal. “If we know that at a certain time global sea level was high, we also know that a relatively continuous layer of claystone would have been deposited,” says Dr. Van der Meer. These deposits of claystone act as seals that prevent the movement of fluids or gases, while sandstone, formed during low sea levels, can serve as a reservoir for water or energy resources.
The precision with which scientists can now reconstruct sea level fluctuations opens new doors for industries and researchers who depend on understanding the behavior of the Earth’s layers. With more accurate maps, scientists can pinpoint locations for safe energy storage, CO2 capture, and the management of radioactive waste, among other applications.
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