Department Lecture - Edwin Kite (U Chicago)

Speaker: 
Edwin Kite (U Chicago)
Date: 
Wednesday, May 12, 2021 - 4:00pm to 5:00pm
Location: 
Virtual via Zoom
How did Mars' surface become uninhabitable
 
Mars’ river valleys are dry today. What allowed rivers and lakes on Early Mars, which received just 1/3 of the modern Earth’s insolation? And why did Mars’ surface become uninhabitable? Data from rovers and orbiters have revealed a rich stratigraphic record of climate-sensitive deposits, allowing models to be tested. We have found that the greenhouse effect of high-altitude water ice clouds is a possible explanation for the warm climates – but only if the surface was arid, consistent with the geologic record. A new synthesis of geologic data and models suggests that water loss, CO2 loss, and loss of non-CO2 greenhouse forcing combined in surprising ways to set Mars’ habitability trajectory. While lake-forming climates on Mars occurred over a time span of >1 Gyr, now Mars’s surface is too cold and dry for life. I will discuss ways in which Martian surface habitability could be re-enabled.