A team of international researchers from the Netherlands, the United Kingdom, and several other nations has presented new findings about the history of water on Mars. Their results suggest that liquid water existed on the planet’s surface for a shorter span in the past than previously believed, which in turn lowers estimates for past habitability. The work appears in the scientific outlet Contact Earth and Environment (CEE).
Lead researcher Lonneke Roelfos, a planetary scientist based at Utrecht University, explains that Mars today has an atmosphere dominated by carbon dioxide, making up roughly 95 percent of its air. She notes that winter temperatures can plunge below minus 120 degrees Celsius, a chilling threshold that causes carbon dioxide to frost out of the atmosphere and form a solid layer on the polar and regolith surfaces.
When the atmospheric CO2 freezes directly into ice, the planet can skip the liquid stage that water normally undergoes in a warming cycle. A parallel process occurs on Earth when water vapor condenses into solid ice crystals that blanket the ground during severe cold spells. Mars follows a similar path, but with a twist born from its thin air and extreme pressures.
As regional or global temperatures rise even briefly, this CO2 ice can sublimate and re-enter the atmosphere as gas. In the Martian environment, this transition happens without passing through a lasting liquid phase, which has important implications for geologic activity and surface modification.
Roelfos highlights a striking consequence of the low atmospheric pressure on Mars: when CO2 changes from solid directly to gas, the released gas can drive rapid, explosive-release events. The expanding gas can scatter and push surface grains apart, triggering flows that reshape landscape features even without liquid water present. Such processes could account for certain surface disturbances observed on Mars today and in the planet’s distant past.
The researchers argue that these CO2-driven processes may have produced grooves and channels that some scientists had previously attributed to ancient watery flow. If true, this reinterpretation would push segments of Mars’s wetter era further back in time and cast doubt on the long-standing view that surface water played a major role in forming those features. The implication is a revision of the planet’s habitability timeline, suggesting that water may have been less abundant or persistent on the surface than once assumed.
In light of this new perspective, the study emphasizes the need to reassess other Martian formations that were once linked to liquid water. It invites continued exploration and modeling to understand how nonwater mechanisms, such as dry ice processes and CO2 outgassing, could account for key geomorphological signatures. The work also underscores the value of cross disciplinary collaboration, combining planetary science, atmospheric chemistry, and geology to build a more complete picture of Mars’s environmental history.
Beyond the fluid history, the report touches on microbial life prospects. The new chronology implies more stringent constraints on when, if ever, Mars could have supported stable, water-based habitats. While the potential for life remains a central question in Mars research, the latest conclusions temper rosy expectations by pointing to shorter windows for liquid water and, consequently, for hospitable conditions suitable for life as we know it.
Finally, the research team notes that ongoing and future missions continuing to analyze Martian surface materials, atmospheric compositions, and climate patterns will be essential. By refining models of ice formation, sublimation cycles, and dust dynamics, scientists can better distinguish features formed by water from those created by dry ice phenomena. This deeper understanding will help map Mars’s past climate with greater fidelity and guide the search for past or present life on the Red Planet with renewed focus and rigor.