Thermodynamic and Energetic Limits on Continental Silicate Weathering Strongly Impact the Climate and Habitability of Wet, Rocky Worlds

Abstract

The "liquid water habitable zone" (HZ) concept is predicated on the ability of the silicate weathering feedback to stabilize climate across a wide range of instellations. However, representations of silicate weathering used in current estimates of the effective outer edge of the HZ do not account for the thermodynamic limit on concentration of weathering products in runoff set by clay precipitation, nor for the energetic limit on precipitation set by planetary instellation. We find that when the thermodynamic limit is included in an idealized coupled climate/weathering model, steady-state planetary climate loses sensitivity to silicate dissolution kinetics, becoming sensitive to temperature primarily through the effect of temperature on runoff and to pCO${}_2$ through an effect on solute concentration mediated by pH. This increases sensitivity to land fraction, CO${}_2$ outgassing, and geological factors such as soil age and lithology, all of which are found to have a profound effect on the position of the effective outer edge of the HZ. The interplay between runoff sensitivity and the energetic limit on precipitation leads to novel warm states in the outer reaches of the HZ, owing to the decoupling of temperature and precipitation. We discuss strategies for detecting the signature of silicate weathering feedback through exoplanet observations in light of insights derived from the revised picture of weathering.

arXiv comment27 pages excluding references, 30 pages total, 8 figures. Submitted to ApJ, accepted 15 May 2020. (reuploaded to arxiv 5/20/2020 to include corresponding author's email address and news of acceptance)

References in corpus (45)

• Habitable Zones Around Main-Sequence Stars: New Estimates
• Solar Models: current epoch and time dependences, neutrinos, and helioseismological properties
• Stabilizing Cloud Feedback Dramatically Expands the Habitable Zone of Tidally Locked Planets
• Constraining the climate and ocean pH of the early Earth with a geological carbon cycle model
• Increased insolation threshold for runaway greenhouse processes on Earth like planets
• Hydrogen Greenhouse Planets Beyond the Habitable Zone
• A revised estimate of the occurrence rate of terrestrial planets in the habitable zones around kepler m-dwarfs
• Strong Dependence of the Inner Edge of the Habitable Zone on Planetary Rotation Rate
• The Role of Plate Tectonic-Climate Coupling and Exposed Land Area in the Development of Habitable Climates on Rocky Planets
• Indication of insensitivity of planetary weathering behavior and habitable zone to surface land fraction
• Outgassing on stagnant-lid super-Earths
• Carbon cycling and habitability of Earth-size stagnant lid planets
• Habitability of Exoplanet Waterworlds
• Climate Stability of Habitable Earth-like Planets
• Limit cycles can reduce the width of the habitable zone
• The atmospheric circulation and climate of terrestrial planets orbiting Sun-like and M-dwarf stars over a broad range of planetary parameters
• A more comprehensive habitable zone for finding life on other planets
• Water Cycling Between Ocean and Mantle: Super-Earths Need Not be Waterworlds
• Climate instability on tidally locked exoplanets
• A Statistical Comparative Planetology Approach to the Hunt for Habitable Exoplanets and Life Beyond the Solar System
• A warmer and wetter solution for early Mars and the challenges with transient warming
• A warm or a cold early Earth? New insights from a 3-D climate-carbon model
• The Habitable Exoplanet Observatory (HabEx) Mission Concept Study Interim Report
• The persistence of oceans on Earth-like planets: insights from the deep-water cycle
• The influence of a sub-stellar continent on the climate of a tidally-locked exoplanet
• A Joint Mass-Radius-Period Distribution of Exoplanets
• Climate Cycling on Early Mars Caused by the Carbonate-Silicate Cycle
• Analytical investigation of the decrease in the size of the habitable zone due to limited CO${}_2$ outgassing rate
• CO2 condensation is a serious limit to the deglaciation of Earth-like planets
• Habitability of Earth-like stagnant lid planets: Climate evolution and recovery from snowball states
• Revisiting the scattering greenhouse effect of CO2 ice clouds
• The impact of stripped cores on the frequency of Earth-size planets in the habitable zone
• The Ice Cap Zone: A Unique Habitable Zone for Ocean Worlds
• GCM Simulations of Unstable Climates in the Habitable Zone
• Climates of Warm Earth-like Planets II: Rotational 'Goldilocks' Zones for Fractional Habitability and Silicate Weathering
• Dependence of the onset of the runaway greenhouse effect on the latitudinal surface water distribution of Earth-like planets
• Long Term Planetary Habitability and the Carbonate-Silicate Cycle
• Inner Edge of Habitable Zones for Earth-sized Planets with Various Surface Water Distributions
• Warming Early Mars with Climate Cycling: The Effect of CO2-H2 Collision-induced Absorption
• Habitable Snowballs: Temperate Land Conditions, Liquid Water, and Implications for CO${}_2$ Weathering
• Effect of surface-mantle water exchange parameterizations on exoplanet ocean depths
• Effects of Radius and Gravity on the Inner Edge of the Habitable Zone
• The effect of high nitrogen pressures on the habitable zone and an appraisal of greenhouse states
• Bifurcation in the growth of continental crust
• A Statistical Comparative Planetology Approach to Maximize the Scientific Return of Future Exoplanet Characterization Efforts

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• Episodic deluges in simulated hothouse climates
• Lithologic Controls on Silicate Weathering Regimes of Temperate Planets
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• Interior Controls on the Habitability of Rocky Planets
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• The Atmospheres of Rocky Exoplanets II. Influence of surface composition on the diversity of cloud condensates
• Blue marble, stagnant lid: Could dynamic topography avert a waterworld?
• How likely are Snowball episodes near the inner edge of the habitable zone?
• High pCO${}_2$ reduces sensitivity to CO${}_2$ perturbations on temperate, Earth-like planets throughout most of habitable zone
• The influence of surface $C{O}_2$ condensation on the evolution of warm and cold rocky planets orbiting Sun-like stars
• CO${}_2$ ocean bistability on terrestrial exoplanets
• Carbon cycle instability for high-$\mathrm{C}{\mathrm{O}}_2$ exoplanets: Implications for habitability
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• Carbon Cycle Imbalances on Arid Terrestrial Planets with Implications for Venus
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• The effect of a biosphere on the habitable timespan of stagnant-lid planets and implications for the atmospheric spectrum
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