Mars regional dust storms trigger massive water loss into space

New research has shown that intense, localized dust storms played a vital role in depriving Mars of its ancient water, fundamentally reshaping our understanding of the planet’s climate evolution.

While geological evidence, such as dry channels and water-altered minerals, shows Mars was once an active, watery world, it has long since transformed into a barren desert.

Scientists have spent decades investigating exactly how the planet lost its water. A new study, published in Communications: Earth & Environment, provides a crucial missing piece by showing that regional dust storms can transport unusually increased amounts of water vapor deep into the Martian upper atmosphere.

Previously, researchers thought that only large, planet-wide storms and the warmer Southern Hemisphere summer contributed significantly to atmospheric water loss.

However, an international team observed a dramatic anomaly during the Northern Hemisphere summer of Martian year 37 (2022-2023 on Earth). A strong, localized dust storm caused water concentrations in the middle atmosphere to rise to ten times above typical levels.

Shortly after this surge, scientists noticed a sharp increase in hydrogen at the exobase—the boundary where the atmosphere merges with space. Hydrogen levels spiked to 2.5 times the usual amount for that season. Because water molecules break apart in the upper atmosphere, tracking this fleeing hydrogen allows researchers to measure the planet’s permanent water loss.

“These results add a vital new piece to the incomplete puzzle of how Mars has been losing its water over billions of years,” said Shohei Aoki, study co-lead from the University of Tokyo.

The findings confirm that short, intense, out-of-season weather events significantly accelerate hydrogen escape, proving that even small-scale storms profoundly impacted the Red Planet’s transition into a desert.