Abstract

Unraveling the details of the ancient Martian climate is one of the major unanswered questions in planetary science. Geological data indicate an episodically warm surface during the early history of Mars (~3-4 billion years ago), but identifying mechanisms that could have warmed the early Martian surface in the face of a faint young sun has remained a challenge.

In this talk I will review new advances in constraining mechanisms that could have supplied significant quantities of H2 to the early Martian atmosphere, and why it may have served as one of the most important greenhouse gases cycled through the early Martian crust-atmosphere system. Together, this new wave of orbital and in-situ observations is permitting a new generation of hypotheses that reconcile short- and long-term climate states with geological constraints.