The session this morning started of with Raymond T. Pierrehumbert‘s talk on Radiative-Convective Modeling of Planetary Climates. The talk, which seems to be a compressed summary of his book, is not for the coffee-deficient attendee. He talks about the modeling of planetary temperature-pressure profiles for planets with a surface, from planets and moons in our solar system to exoplanets such as GJ1214 b. He touches upon the conventional habitable zone and the runaway-greenhouse effects associated with the edges of the zone as well as the importance of GCM models in understanding large scale dynamics over the classic 1D model approcach.
The second speaker A. Lenardic presents a talk titled Tectonic Regimes of Terrestrial Planets & Exoclimes. Keywords: plate tectonics and mantle convection. He talks about the numerical simulations of convections in the mantle and argues it is likely that a planet the size of Venus/Earth have changing tectonic regimes (stagnant lid/episodic outflows/plates tectonics) over the planet’s lifetime. But what about Super-Earths, do they even have tectonic plates in the first place? Some groups say yes, other groups say no. They might both be right, as the presence of tectonics depends heavily on the geodynamical history of the planet.
Dorian Abbot continues with a rather refreshing classic blackboard presentation on weathering feedbacks of planets in the habitable zone. In short, if CO2 is not removed from the atmosphere by weathering there will be a runaway greenhouse effect making the exoplanet non-habitable. If you assume seafloor weathering is independant of surface temperature and set the land fraction to zero, increases in CO2 concentration can not be moderated efficiently. But as long as there is a non-zero land fraction, however small, the CO2 feedback can keep the planet habitable.