The past inside the present: Bridging the gap between the solar system and exoplanets via climate evolution research

15 Feb
Atmospheric & Environmental Chemistry Seminar
Robin Wordsworth
Friday, February 15, 2019 - 12:00pm to 1:00pm
MD G-115

The current era of planetary climate research is characterized by a divide
between the solar system, where data is rich but the number of objects to be
studied is small, and exoplanets, where data is sparse but the full range of
possible states is extremely large. Paleoclimate research is an essential tool with
which to bridge this gap, because it allows us to see the present-day surface
environments of Earth, Mars and Venus as mere snapshots of nonlinear systems
that have evolved significantly over time. Here, I focus on Mars as a case study
to show how this approach can yield important insights in practice. Mars has
abundant evidence for intermittent habitable conditions in its first gigayear of
evolution, but the theoretical explanation for this evidence is a long-standing
problem in the field. I discuss how detailed intercomparisons between 3D climate
models and the geological evidence have allowed us to gain new insights into the
nature of the early Martian hydrological cycle. In addition, new spectroscopic and
radiative calculations show that episodic release of reducing gases (CH4 and H2)
into Mars’ early atmosphere could have caused intense intermittent warming,
potentially resolving the decades-old faint young Sun problem. Based on these
insights into Mars’ climate and redox history, we are now developing a
greater understanding of exoplanet atmospheric evolution, including the critical
question of whether species like oxygen (O2) can be treated as biosignatures, or
remote signs of life.

Kelvin Bates