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Updated: Nov 27, 2025

Simulation of the Planetary Interior Differentiation Processes in the Laboratory
Published on: November 15, 2013
Carbonate-silicate cycle predictions of Earth-like planetary climates and testing the habitable zone concept
Owen R Lehmer1,2,3, David C Catling4,5, Joshua Krissansen-Totton5,6
1MS 239-4, Space Science Division, NASA Ames Research Center, Moffett Field, CA, 94035, USA. owen.r.lehmer@nasa.gov.
Abstract:
In the conventional habitable zone (HZ) concept, a CO2-H2O greenhouse maintains surface liquid water. Through the water-mediated carbonate-silicate weathering cycle, atmospheric CO2 partial pressure (pCO2) responds to changes in surface temperature, stabilizing the climate over geologic timescales. We show that this weathering feedback ought to produce a log-linear relationship between pCO2 and incident flux on Earth-like planets in the HZ. However, this trend has scatter because geophysical and physicochemical parameters can vary, such as land area for weathering and CO2 outgassing fluxes. Using a coupled climate and carbonate-silicate weathering model, we quantify the likely scatter in pCO2 with orbital distance throughout the HZ. From this dispersion, we predict a two-dimensional relationship between incident flux and pCO2 in the HZ and show that it could be detected from at least 83 (2σ) Earth-like exoplanet observations. If fewer Earth-like exoplanets are observed, testing the HZ hypothesis from this relationship could be difficult.
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