New research suggests that thin layers of ice may have kept lakes on ancient Mars from freezing, allowing liquid water to exist even during colder periods. This finding could help explain the puzzling history of water on the Red Planet.
The study, led by Eleanor Moreland from Rice University, used data from NASA’s Curiosity rover in Gale Crater. Moreland explained that if similar conditions occurred elsewhere on Mars, it might support the idea that even a cold Mars could have sustained liquid water, a crucial factor for life.
Various signs point to Mars having once hosted liquid water, such as dried riverbeds and lake channels. Initially, scientists thought these features indicated a warm, wet planet. However, evidence shows that Mars was cooler than previously believed. About four billion years ago, it likely had a much thinner carbon dioxide atmosphere, making it hard to maintain warmer temperatures, especially when the sun was only 75% as bright as today.
This creates a paradox: how could there be evidence of liquid water on a planet that seemed too cold for it? To tackle this question, researchers are investigating ways Mars could have supported water without being particularly warm.
Moreland collaborated with Sylvia Dee, an Earth climate scientist, to adapt a climate model usually used for Earth. They created the Lake Modeling on Mars with Atmospheric Reconstructions and Simulations (LakeM2ARS) model by using data from Curiosity about Mars’ rock and mineral records. It was a challenging but rewarding process, as they had to adjust for Martian gravity and other factors.
In their research, they ran 64 simulations of a hypothetical lake in Gale Crater, representing conditions from about 3.6 billion years ago. Some scenarios showed the lake completely freezing in winter, while others revealed a thin ice layer forming that insulated the water below. In spring and summer, the ice would melt, allowing liquid water to return each year while maintaining stability over decades, even during freezing temperatures.
As Moreland noted, this model suggests a way lakes on Mars could have persisted long after warmer conditions faded. While the study doesn’t rule out warmer periods in Mars’ past, it offers insight into how liquid water might have survived in a colder climate.
This research sheds light on the complex history of Mars and how it could shape our understanding of potential life beyond Earth. It highlights the ongoing quest to unlock the mysteries of our neighboring planet.
For those interested, the findings were published in the December 29, 2025, issue of AGU Advances.
