What is one of the two main pathways scientists agree contributed to the disappearance of Mars's large water reservoir?

Answer

Solar wind stripping due to magnetic field loss

As Mars lost its global magnetic field, the solar wind accelerated the stripping away of much of its atmosphere, causing surface pressure to drop so that liquid water could no longer exist freely.

What is one of the two main pathways scientists agree contributed to the disappearance of Mars's large water reservoir?
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