25 Mar (CLIM) Sohl, Climate Without Vegetation

Linda Sohl, Columbia U

Dust in the wind: Climatic effects of aerosol loading on non-vegetated worlds

Wed, 25 Mar, 1:30pm 

Innovation Hall 131 and via Zoom (for link, email bklinger@gmu.edu)

Host: Alia Wofford

The possibility that Precambrian climate was much cooler than previously thought has implications for Earth’s ability to enter and recover from Snowball Earth states, and more broadly, for the potential habitability of terrestrial exoplanets. To assess whether a non-vegetated land surface should necessarily lead to a dustier and colder environment, we explored the Ordovician climate circa 450 Ma, prior to the expansion of vascular land plants. Despite an insolation slightly lower than modern, estimates of higher levels of CO2 suggest that this climate would have been warm and ice-free. Using the ROCKE-3D exoplanet GCM, we find the maximum amount of dust-driven cooling to be no more than 2.5˚C, far less than in Liu et al (2020). Our results suggest that aerosol effects depend greatly on specific boundary conditions, such as continental distribution and atmospheric chemistry.