The loss of water on Mars was due to the changing seasons and storms on the planet. This is reported by the European Space Agency (ESA).

Mars lost most of its once-abundant water, and a small amount remained in the planet’s atmosphere. ESA’s Mars Express satellite helped scientists figure out that moisture from the Red Planet continues to escape into space. This process is accelerated by dust storms.

Despite the aridity today, Mars probably was once a water-covered world like ours. Evidence of this is visible in images of the vast, flood-formed outflow channels of river valleys and deltas carved into the planet’s surface. In addition, the theory is supported by long radar observations of reservoirs of liquid water trapped under the ice and dust of Mars’ south pole.

Now water can only exist on Mars in the form of ice or gas due to the planet’s low atmospheric pressure, which is less than 1% of Earth’s. Most of Mars’ water has ended up rushing into space over the past several billion years. And this process continues.

Two new studies led by Anna Fedorova of the Space Research Institute of the Russian Academy of Sciences and Jean-Yves Chaofre of Laboratoire Atmospheres Observations Spatiales (France) explain how water flows through and out of Mars’ atmosphere. It turned out that this process is influenced by the planet’s distance from the Sun and changes in its climate and weather. This includes massive global dust storms often observed on Mars.

Through constant monitoring of Mars Express, scientists have analyzed the last two global dust storms, in 2007 and 2018. They compared the performance of those years with years without storms to understand how storms affected the leakage of water from Mars.

With the change of seasons, moisture freezes in the atmosphere of Mars. However, instead of returning to Earth in the form of precipitation, something else happens. Dust storms interfere with the process. They heat and destroy the atmosphere of Mars, and also deliver water to even greater heights.

Both studies used extensive multi-year datasets from the Mars Express orbiter SPICAM.

A high-resolution stereo camera aboard ESA’s Mars Express captured a rising front of dust clouds – visible in the right half of the frame above – near Mars’ north polar ice cap in April this year. It was one of several local small-scale dust storms that have been observed in recent months on the Red Planet. A larger storm emerged further southwest in late May and within a few weeks turned into a global dust storm that engulfs the entire planet.