Evidence suggests that Mars once hosted significant amounts of water. Past studies indicate that the majority of atmospheric water loss occurs during the Martian southern summer. During this season, warm and dusty conditions allow water vapor to ascend to high altitudes, where it escapes into space without condensing. A groundbreaking study has unveiled a previously unidentified pathway for water loss, observed for the first time in the Martian northern summer. This research highlights how a localized, short-lived sandstorm in Mars Year 37 (August 2023) caused a surge in water vapor.
Close-up color image of a small dust storm on Mars, captured by ESA’s Mars Express’ HRSC instrument in April 2018. Image credit: ESA / DLR / FU Berlin / CC BY-SA 3.0 IGO.
Dr. Adrian Brines, a researcher at the Andalusian Institute of Astronomy and the University of Tokyo, stated, “Our findings reveal the impact of this type of storm on Earth’s climate evolution and open new avenues for understanding how Mars has lost water over time.”
While dust storms have long been recognized as significant contributors to water escape on Mars, previous discussions primarily focused on large-scale dust events occurring on a planetary scale.
In this study, Dr. Brines and colleagues demonstrated that smaller, localized storms can significantly enhance the transport of water vapor to high altitudes, where it is lost to space more readily.
Prior research concentrated on the warm and dynamic summers of the Southern Hemisphere, as this is the primary period for water loss on Mars.
The recent study detected an unusual spike in water vapor in Mars’ middle atmosphere, attributed to a localized dust storm during the northern hemisphere summer of Martian year 37.
Diagram demonstrating the atmospheric response to localized sandstorms in the Northern Hemisphere during summer. High dust concentrations significantly enhance solar radiation absorption, promoting atmospheric warming, especially in the middle atmosphere. This increased circulation enhances the vertical transport of water vapor, facilitating its injection at high altitudes and increasing hydrogen efflux from the exobase. Image credit: Brines et al., doi: 10.1038/s43247-025-03157-5.
This surge in water vapor was unprecedented, reaching levels up to 10 times higher than normal—an occurrence not predicted by existing climate models or observed in previous Martian epochs.
Following this event, the amount of hydrogen in Mars’ exobase—where the atmosphere transitions into space—also rose significantly, increasing by 2.5 times compared to the previous year.
Understanding how much water Mars has lost over time hinges on measuring the hydrogen that escapes into space, as this element is produced when water decomposes in the atmosphere.
Dr. Shohei Aoki, a researcher at the University of Tokyo and Tohoku University, noted, “These results provide a crucial piece to the incomplete puzzle of how Mars has persistently lost water over billions of years, demonstrating that brief but intense episodes can significantly influence the evolution of Mars’ climate.”
Discover more about these findings in the featured study, published this week in Communication: Earth and Environment.
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A. Brines et al. 2026. Unseasonal water escape during summer in Mars’ northern hemisphere caused by localized strong sandstorms. Communication: Earth and Environment 7, 55; doi: 10.1038/s43247-025-03157-5
Source: www.sci.news
