Archean Earth Climate Drivers

The Archean Eon (4.0 - 2.5 Ga) is a very important time period: it spans roughly one third of Earth’s history, likely hosted the earliest lifeforms, and was critical for the development and long-term maintenance of a habitable climate and surface conditions on Earth. There are very few physical proxy records stretching all the way back to the Archean, meaning that early Earth climate research is centered on computer modeling with proxy data as validation. This kind of research has built a solid understanding of what atmospheric and surface conditions were like on Archean Earth, and now we can shift focus and investigate why the climate changed so drastically during this period. This project aims to identify the primary drivers of Archean climate change by completing a large parameter sweep with Isca - a highly configurable framework designed for idealized terrestrial planetary atmospheres. Working back from present day Earth, boundary conditions will be changed one at a time in order to isolate their specific role in the climate change over the Archean period. Simulations with interesting results will then be passed to ROCKE-3D, to further evaluate with a fully-coupled earth system model. The first suite of simulations will investigate the roles of three parameters that are intrinsic to Archean conditions: reduced solar luminosity, enhanced rotation rate, and a vastly different atmospheric composition. In later work more complexities will be added, and the role of land type, continental configuration, and orbital parameters (plus many more) will be investigated. The preliminary results of the initial suite of simulations will be presented here. By isolating the role of an extensive set of atmosphere, ocean, geologic, and orbital parameters using a simple model framework, we hope to identify the primary drivers of Archean climate change. This will help to quantify the relative importance of each variable in terms of planetary habitability, and can potentially be extrapolated to benefit the search for habitable planets outside of our solar system.