Planetary relevance of the carbonate-silicate weathering feedback

In the search for habitable worlds beyond the solar system the habitable zone (HZ) is a valuable concept indicating an increased likelihood of sustained liquid water on a planet’s surface within a limited range of distances to a host star. In the conservative HZ hypothesis, a functioning carbonate-silicate cycle acts as a weathering thermostat, which is thought to stabilise the planetary climate throughout the HZ by creating a decreasing trend of atmospheric CO₂ with incident stellar flux.

We are assessing requirements needed to test the prevalence of this negative feedback with population scale observations of terrestrial exoplanet atmospheres. For this we use CO₂-Flux trend predictions for Earth-like HZ planets based on coupled climate and carbonate-silicate weathering models (Lehmer et al., 2020).