NASA finds dust storms behind Red Planet's massive water loss

Dust storms on Mars that fling water out of the planet's atmosphere play a bigger role in making it the arid world it is today, NASA researchers have found.

New data from the space agency's Mars Atmosphere and Volatile Evolution (MAVEN) orbiter has led to a rethink about how the Red Planet loses water.

Scientists have long believed it was through of a slow, steady process that breaks water molecules apart in the lower layers of the atmosphere.

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But when University of Arizona researchers examined the MAVEN data they found the upper part of the atmosphere dumped more water at certain times.

Their studies revealed a seasonal pattern – the upper atmosphere contained the most water when Mars was closest to the sun or when there was a major dust storm.

The atmospheric warming caused by those events allows water to float higher in the Red Planet's air.

"This was really a smack in the face," Shane Stone, University of Arizona researchers said.

"The global dust storm stands out in the data like nothing else."

During global dust storms, 20 times more water can be transported to the upper atmosphere.

The researchers calculated that over the past billion years, Mars's upper atmosphere may have leaked out enough water to cover the planet's surface in a liquid layer 61cm deep.

"Mars must have lost the equivalent of a global ocean tens to hundreds of metres deep over its entire history," Dr Stone said.