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Liu J, Yang J, Ding F, Chen G, Hu Y. Hydrologic cycle weakening in hothouse climates. SCIENCE ADVANCES 2024; 10:eado2515. [PMID: 38657064 PMCID: PMC11042734 DOI: 10.1126/sciadv.ado2515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Accepted: 03/20/2024] [Indexed: 04/26/2024]
Abstract
The hydrologic cycle has wide impacts on the ocean salinity and circulation, carbon and nitrogen cycles, and the ecosystem. Under anthropogenic global warming, previous studies showed that the intensification of the hydrologic cycle is a robust feature. Whether this trend persists in hothouse climates, however, is unknown. Here, we show in climate models that mean precipitation first increases with rising surface temperature, but the precipitation trend reverses when the surface is hotter than ~320 to 330 kelvin. This nonmonotonic phenomenon is robust to the cause of warming, convection scheme, ocean dynamics, atmospheric mass, planetary rotation, gravity, and stellar spectrum. The weakening occurs because of the existence of an upper limitation of outgoing longwave emission and the continuously increasing shortwave absorption by H2O and is consistent with atmospheric dynamics featuring the strong increase of atmospheric stratification and marked reduction of convective mass flux. These results have wide implications for the climate evolutions of Earth, Venus, and potentially habitable exoplanets.
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Affiliation(s)
- Jiachen Liu
- Laboratory for Climate and Ocean-Atmosphere Studies, Department of Atmospheric and Oceanic Sciences, School of Physics, Peking University, Beijing 100871, China
| | - Jun Yang
- Laboratory for Climate and Ocean-Atmosphere Studies, Department of Atmospheric and Oceanic Sciences, School of Physics, Peking University, Beijing 100871, China
| | - Feng Ding
- Laboratory for Climate and Ocean-Atmosphere Studies, Department of Atmospheric and Oceanic Sciences, School of Physics, Peking University, Beijing 100871, China
| | - Gang Chen
- Department of Atmospheric and Oceanic Sciences, University of California-Los Angeles, Los Angeles, CA 90095, USA
| | - Yongyun Hu
- Laboratory for Climate and Ocean-Atmosphere Studies, Department of Atmospheric and Oceanic Sciences, School of Physics, Peking University, Beijing 100871, China
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2
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Wu H, Murray N, Menou K, Lee C, Leconte J. Why the day is 24 hours long: The history of Earth's atmospheric thermal tide, composition, and mean temperature. SCIENCE ADVANCES 2023; 9:eadd2499. [PMID: 37406113 DOI: 10.1126/sciadv.add2499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 06/07/2023] [Indexed: 07/07/2023]
Abstract
The Sun drives a semidiurnal (12-hour) thermal tide in Earth's atmosphere. Zahnle and Walker suggested that an atmospheric oscillation with period Pres ≈ 10.5 hours resonated with the Solar driving ≈600 million years ago (Ma), when the length of day (lod) was ≈21 hours. They argued that the enhanced torque balanced the Lunar tidal torque, fixing the lod. We explore this hypothesis using two different global circulation models (GCMs), finding Pres = 11.4 and 11.5 hours today, in excellent agreement with a recent measurement. We quantify the relation between Pres, mean surface temperature [Formula: see text], composition, and Solar luminosity. We use geologic data, a dynamical model, and a Monte Carlo sampler to find possible histories for the Earth-Moon system. In the most likely model, the lod was fixed at ≈19.5 hours between 2200 and 600 Ma ago, with sustained high [Formula: see text] and an increase in the angular momentum LEM of the Earth-Moon system of ≈5%.
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Affiliation(s)
- Hanbo Wu
- Canadian Institute for Theoretical Astrophysics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 3H8, Canada
- Department of Physics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 1A7, Canada
| | - Norman Murray
- Canadian Institute for Theoretical Astrophysics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 3H8, Canada
- Department of Physics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 1A7, Canada
- David A. Dunlap Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, Ontario M5S 3H4, Canada
| | - Kristen Menou
- David A. Dunlap Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, Ontario M5S 3H4, Canada
- Physics and Astrophysics Group, Department of Physical & Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario M1C 1A4, Canada
| | - Christopher Lee
- Department of Physics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 1A7, Canada
| | - Jeremy Leconte
- Laboratoire d'astrophysique de Bordeaux, Univ. Bordeaux, CNRS, B18N, Allée Geoffroy Saint-Hilaire, F-33615 Pessac, France
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Zhang Y, Bloch‐Johnson J, Romps DM, Abbot DS. Evolving CO 2 Rather Than SST Leads to a Factor of Ten Decrease in GCM Convergence Time. JOURNAL OF ADVANCES IN MODELING EARTH SYSTEMS 2021; 13:e2021MS002505. [PMID: 34820055 PMCID: PMC8596447 DOI: 10.1029/2021ms002505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Revised: 06/08/2021] [Accepted: 08/12/2021] [Indexed: 06/13/2023]
Abstract
The high computational cost of Global Climate Models (GCMs) is a problem that limits their use in many areas. Recently an inverse climate modeling (InvCM) method, which fixes the global mean sea surface temperature (SST) and evolves theC O 2 mixing ratio to equilibrate climate, has been implemented in a cloud-resolving model. In this article, we apply InvCM to ExoCAM GCM aquaplanet simulations, allowing the SST pattern to evolve while maintaining a fixed global-mean SST. We find that InvCM produces the same climate as normal slab-ocean simulations but converges an order of magnitude faster. We then use InvCM to calculate the equilibriumC O 2 for SSTs ranging from 290 to 340 K at 1 K intervals and reproduce the large increase in climate sensitivity at an SST of about 315 K at much higher temperature resolution. The speedup provided by InvCM could be used to equilibrate GCMs at higher spatial resolution or to perform broader parameter space exploration in order to gain new insight into the climate system. Additionally, InvCM could be used to find unstable and hidden climate states, and to find climate states close to bifurcations such as the runaway greenhouse transition.
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Affiliation(s)
- Yixiao Zhang
- Department of the Atmospheric and Oceanic SciencesPeking UniversityBeijingChina
| | | | - David M. Romps
- Department of Earth and Planetary ScienceUniversity of CaliforniaBerkeleyCAUSA
- Climate and Ecosystem Sciences DivisionLawrence Berkeley National LaboratoryBerkeleyCAUSA
| | - Dorian S. Abbot
- Department of the Geophysical SciencesUniversity of ChicagoChicagoILUSA
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Turbet M, Bolmont E, Chaverot G, Ehrenreich D, Leconte J, Marcq E. Day-night cloud asymmetry prevents early oceans on Venus but not on Earth. Nature 2021; 598:276-280. [PMID: 34645997 DOI: 10.1038/s41586-021-03873-w] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 08/03/2021] [Indexed: 11/09/2022]
Abstract
Earth has had oceans for nearly four billion years1 and Mars had lakes and rivers 3.5-3.8 billion years ago2. However, it is still unknown whether water has ever condensed on the surface of Venus3,4 because the planet-now completely dry5-has undergone global resurfacing events that obscure most of its history6,7. The conditions required for water to have initially condensed on the surface of Solar System terrestrial planets are highly uncertain, as they have so far only been studied with one-dimensional numerical climate models3 that cannot account for the effects of atmospheric circulation and clouds, which are key climate stabilizers. Here we show using three-dimensional global climate model simulations of early Venus and Earth that water clouds-which preferentially form on the nightside, owing to the strong subsolar water vapour absorption-have a strong net warming effect that inhibits surface water condensation even at modest insolations (down to 325 watts per square metre, that is, 0.95 times the Earth solar constant). This shows that water never condensed and that, consequently, oceans never formed on the surface of Venus. Furthermore, this shows that the formation of Earth's oceans required much lower insolation than today, which was made possible by the faint young Sun. This also implies the existence of another stability state for present-day Earth: the 'steam Earth', with all the water from the oceans evaporated into the atmosphere.
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Affiliation(s)
- Martin Turbet
- Observatoire astronomique de l'Université de Genève, Versoix, Switzerland.
| | - Emeline Bolmont
- Observatoire astronomique de l'Université de Genève, Versoix, Switzerland
| | - Guillaume Chaverot
- Observatoire astronomique de l'Université de Genève, Versoix, Switzerland
| | - David Ehrenreich
- Observatoire astronomique de l'Université de Genève, Versoix, Switzerland
| | - Jérémy Leconte
- Laboratoire d'astrophysique de Bordeaux, Université de Bordeaux, CNRS, B18N, Pessac, France
| | - Emmanuel Marcq
- LATMOS/IPSL, UVSQ, Université Paris-Saclay, Sorbonne Université, CNRS, Guyancourt, France
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Catling DC, Zahnle KJ. The Archean atmosphere. SCIENCE ADVANCES 2020; 6:eaax1420. [PMID: 32133393 PMCID: PMC7043912 DOI: 10.1126/sciadv.aax1420] [Citation(s) in RCA: 96] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 12/10/2019] [Indexed: 05/05/2023]
Abstract
The atmosphere of the Archean eon-one-third of Earth's history-is important for understanding the evolution of our planet and Earth-like exoplanets. New geological proxies combined with models constrain atmospheric composition. They imply surface O2 levels <10-6 times present, N2 levels that were similar to today or possibly a few times lower, and CO2 and CH4 levels ranging ~10 to 2500 and 102 to 104 times modern amounts, respectively. The greenhouse gas concentrations were sufficient to offset a fainter Sun. Climate moderation by the carbon cycle suggests average surface temperatures between 0° and 40°C, consistent with occasional glaciations. Isotopic mass fractionation of atmospheric xenon through the Archean until atmospheric oxygenation is best explained by drag of xenon ions by hydrogen escaping rapidly into space. These data imply that substantial loss of hydrogen oxidized the Earth. Despite these advances, detailed understanding of the coevolving solid Earth, biosphere, and atmosphere remains elusive, however.
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Affiliation(s)
- David C. Catling
- Department of Earth and Space Sciences and cross-campus Astrobiology Program, Box 351310, University of Washington, Seattle, WA 98195, USA
| | - Kevin J. Zahnle
- Space Sciences Division, NASA Ames Research Center, MS 245-3, Moffett Field, CA 94035, USA
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6
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Stellar Activity Effects on Moist Habitable Terrestrial Atmospheres around M Dwarfs. ACTA ACUST UNITED AC 2019. [DOI: 10.3847/1538-4357/ab32e8] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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7
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Habitability and Spectroscopic Observability of Warm M-dwarf Exoplanets Evaluated with a 3D Chemistry-Climate Model. ACTA ACUST UNITED AC 2019. [DOI: 10.3847/1538-4357/ab4f7e] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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8
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Del Genio AD, Kiang NY, Way MJ, Amundsen DS, Sohl LE, Fujii Y, Chandler M, Aleinov I, Colose CM, Guzewich SD, Kelley M. Albedos, Equilibrium Temperatures, and Surface Temperatures of Habitable Planets. THE ASTROPHYSICAL JOURNAL 2019; 884:75. [PMID: 33100349 PMCID: PMC7580787 DOI: 10.3847/1538-4357/ab3be8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The potential habitability of known exoplanets is often categorized by a nominal equilibrium temperature assuming a Bond albedo of either ∼0.3, similar to Earth, or 0. As an indicator of habitability, this leaves much to be desired, because albedos of other planets can be very different, and because surface temperature exceeds equilibrium temperature due to the atmospheric greenhouse effect. We use an ensemble of general circulation model simulations to show that for a range of habitable planets, much of the variability of Bond albedo, equilibrium temperature and even surface temperature can be predicted with useful accuracy from incident stellar flux and stellar temperature, two known parameters for every confirmed exoplanet. Earth's Bond albedo is near the minimum possible for habitable planets orbiting G stars, because of increasing contributions from clouds and sea ice/snow at higher and lower instellations, respectively. For habitable M star planets, Bond albedo is usually lower than Earth's because of near-IR H2O absorption, except at high instellation where clouds are important. We apply relationships derived from this behavior to several known exoplanets to derive zeroth-order estimates of their potential habitability. More expansive multivariate statistical models that include currently non-observable parameters show that greenhouse gas variations produce significant variance in albedo and surface temperature, while increasing length of day and land fraction decrease surface temperature; insights for other parameters are limited by our sampling. We discuss how emerging information from global climate models might resolve some degeneracies and help focus scarce observing resources on the most promising planets.
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Affiliation(s)
- Anthony D Del Genio
- NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY 10025, USA
| | - Nancy Y Kiang
- NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY 10025, USA
| | - Michael J Way
- NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY 10025, USA
| | - David S Amundsen
- NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY 10025, USA
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY 10027, USA
| | - Linda E Sohl
- NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY 10025, USA
- Center for Climate Systems Research, Columbia University, New York, NY 10027, USA
| | - Yuka Fujii
- Earth-Life Science Institute, Tokyo Institute of Technology, Ookayama, Meguro, Tokyo 152-8550, Japan
| | - Mark Chandler
- NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY 10025, USA
- Center for Climate Systems Research, Columbia University, New York, NY 10027, USA
| | - Igor Aleinov
- NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY 10025, USA
- Center for Climate Systems Research, Columbia University, New York, NY 10027, USA
| | - Christopher M Colose
- NASA Postdoctoral Program, Goddard Institute for Space Studies, New York, NY 10025, USA
| | | | - Maxwell Kelley
- NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY 10025, USA
- SciSpace LLC, 2880 Broadway, New York, NY 10025, USA
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9
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Lammer H, Sproß L, Grenfell JL, Scherf M, Fossati L, Lendl M, Cubillos PE. The Role of N 2 as a Geo-Biosignature for the Detection and Characterization of Earth-like Habitats. ASTROBIOLOGY 2019; 19:927-950. [PMID: 31314591 DOI: 10.1089/ast.2018.1914] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Since the Archean, N2 has been a major atmospheric constituent in Earth's atmosphere. Nitrogen is an essential element in the building blocks of life; therefore, the geobiological nitrogen cycle is a fundamental factor in the long-term evolution of both Earth and Earth-like exoplanets. We discuss the development of Earth's N2 atmosphere since the planet's formation and its relation with the geobiological cycle. Then we suggest atmospheric evolution scenarios and their possible interaction with life-forms: first for a stagnant-lid anoxic world, second for a tectonically active anoxic world, and third for an oxidized tectonically active world. Furthermore, we discuss a possible demise of present Earth's biosphere and its effects on the atmosphere. Since life-forms are the most efficient means for recycling deposited nitrogen back into the atmosphere at present, they sustain its surface partial pressure at high levels. Also, the simultaneous presence of significant N2 and O2 is chemically incompatible in an atmosphere over geological timescales. Thus, we argue that an N2-dominated atmosphere in combination with O2 on Earth-like planets within circumstellar habitable zones can be considered as a geo-biosignature. Terrestrial planets with such atmospheres will have an operating tectonic regime connected with an aerobic biosphere, whereas other scenarios in most cases end up with a CO2-dominated atmosphere. We conclude with implications for the search for life on Earth-like exoplanets inside the habitable zones of M to K stars.
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Affiliation(s)
- Helmut Lammer
- 1Austrian Academy of Sciences, Space Research Institute, Graz, Austria
| | - Laurenz Sproß
- 1Austrian Academy of Sciences, Space Research Institute, Graz, Austria
- 2Institute of Physics, University of Graz, Graz, Austria
| | - John Lee Grenfell
- 3Department of Extrasolar Planets and Atmospheres, German Aerospace Center, Institute of Planetary Research, Berlin, Germany
| | - Manuel Scherf
- 1Austrian Academy of Sciences, Space Research Institute, Graz, Austria
| | - Luca Fossati
- 1Austrian Academy of Sciences, Space Research Institute, Graz, Austria
| | - Monika Lendl
- 1Austrian Academy of Sciences, Space Research Institute, Graz, Austria
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10
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Way M, Del Genio AD, Aleinov I, Clune TL, Kelley M, Kiang NY. Climates of Warm Earth-like Planets I: 3-D Model Simulations. THE ASTROPHYSICAL JOURNAL. SUPPLEMENT SERIES 2018; 239:24. [PMID: 30948861 PMCID: PMC6443379 DOI: 10.3847/1538-4365/aae9e1] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We present a large ensemble of simulations of an Earth-like world with increasing insolation and rotation rate. Unlike previous work utilizing idealized aquaplanet configurations we focus our simulations on modern Earth-like topography. The orbital period is the same as modern Earth, but with zero obliquity and eccentricity. The atmosphere is 1 bar N2-dominated with CO2=400 ppmv and CH4=1 ppmv. The simulations include two types of oceans; one without ocean heat transport (OHT) between grid cells as has been commonly used in the exoplanet literature, while the other is a fully coupled dynamic bathtub type ocean. The dynamical regime transitions that occur as day length increases induce climate feedbacks producing cooler temperatures, first via the reduction of water vapor with increasing rotation period despite decreasing shortwave cooling by clouds, and then via decreasing water vapor and increasing shortwave cloud cooling, except at the highest insolations. Simulations without OHT are more sensitive to insolation changes for fast rotations while slower rotations are relatively insensitive to ocean choice. OHT runs with faster rotations tend to be similar with gyres transporting heat poleward making them warmer than those without OHT. For slower rotations OHT is directed equator-ward and no high latitude gyres are apparent. Uncertainties in cloud parameterization preclude a precise determination of habitability but do not affect robust aspects of exoplanet climate sensitivity. This is the first paper in a series that will investigate aspects of habitability in the simulations presented herein. The datasets from this study are opensource and publicly available.
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Affiliation(s)
- M.J. Way
- NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY, 10025, USA
- Department of Physics and Astronomy, Uppsala University, Uppsala, 75120, Sweden
| | - Anthony D. Del Genio
- NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY, 10025, USA
| | - Igor Aleinov
- NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY, 10025, USA
- Center for Climate Systems Research, Columbia University, New York, NY 10025, USA
| | - Thomas L. Clune
- Global Modeling and Assimilation Office, NASA Goddard Space Flight Center, USA
| | - Maxwell Kelley
- NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY, 10025, USA
| | - Nancy Y. Kiang
- NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY, 10025, USA
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12
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Meadows VS, Arney GN, Schwieterman EW, Lustig-Yaeger J, Lincowski AP, Robinson T, Domagal-Goldman SD, Deitrick R, Barnes RK, Fleming DP, Luger R, Driscoll PE, Quinn TR, Crisp D. The Habitability of Proxima Centauri b: Environmental States and Observational Discriminants. ASTROBIOLOGY 2018; 18:133-189. [PMID: 29431479 PMCID: PMC5820795 DOI: 10.1089/ast.2016.1589] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 09/04/2017] [Indexed: 05/21/2023]
Abstract
Proxima Centauri b provides an unprecedented opportunity to understand the evolution and nature of terrestrial planets orbiting M dwarfs. Although Proxima Cen b orbits within its star's habitable zone, multiple plausible evolutionary paths could have generated different environments that may or may not be habitable. Here, we use 1-D coupled climate-photochemical models to generate self-consistent atmospheres for several evolutionary scenarios, including high-O2, high-CO2, and more Earth-like atmospheres, with both oxic and anoxic compositions. We show that these modeled environments can be habitable or uninhabitable at Proxima Cen b's position in the habitable zone. We use radiative transfer models to generate synthetic spectra and thermal phase curves for these simulated environments, and use instrument models to explore our ability to discriminate between possible planetary states. These results are applicable not only to Proxima Cen b but to other terrestrial planets orbiting M dwarfs. Thermal phase curves may provide the first constraint on the existence of an atmosphere. We find that James Webb Space Telescope (JWST) observations longward of 10 μm could characterize atmospheric heat transport and molecular composition. Detection of ocean glint is unlikely with JWST but may be within the reach of larger-aperture telescopes. Direct imaging spectra may detect O4 absorption, which is diagnostic of massive water loss and O2 retention, rather than a photosynthetic biosphere. Similarly, strong CO2 and CO bands at wavelengths shortward of 2.5 μm would indicate a CO2-dominated atmosphere. If the planet is habitable and volatile-rich, direct imaging will be the best means of detecting habitability. Earth-like planets with microbial biospheres may be identified by the presence of CH4-which has a longer atmospheric lifetime under Proxima Centauri's incident UV-and either photosynthetically produced O2 or a hydrocarbon haze layer. Key Words: Planetary habitability and biosignatures-Planetary atmospheres-Exoplanets-Spectroscopic biosignatures-Planetary science-Proxima Centauri b. Astrobiology 18, 133-189.
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Affiliation(s)
- Victoria S. Meadows
- Astronomy Department, University of Washington, Seattle, Washington
- NASA Astrobiology Institute—Virtual Planetary Laboratory Lead Team, USA
| | - Giada N. Arney
- Astronomy Department, University of Washington, Seattle, Washington
- NASA Astrobiology Institute—Virtual Planetary Laboratory Lead Team, USA
- Planetary Systems Laboratory, NASA Goddard Space Flight Center, Greenbelt, Maryland
| | - Edward W. Schwieterman
- Astronomy Department, University of Washington, Seattle, Washington
- NASA Astrobiology Institute—Virtual Planetary Laboratory Lead Team, USA
- NASA Postdoctoral Program, Universities Space Research Association, Columbia, Maryland
- Department of Earth Sciences, University of California at Riverside, Riverside, California
| | - Jacob Lustig-Yaeger
- Astronomy Department, University of Washington, Seattle, Washington
- NASA Astrobiology Institute—Virtual Planetary Laboratory Lead Team, USA
| | - Andrew P. Lincowski
- Astronomy Department, University of Washington, Seattle, Washington
- NASA Astrobiology Institute—Virtual Planetary Laboratory Lead Team, USA
| | - Tyler Robinson
- NASA Astrobiology Institute—Virtual Planetary Laboratory Lead Team, USA
- Department of Astronomy and Astrophysics, University of California, Santa Cruz, California
| | - Shawn D. Domagal-Goldman
- NASA Astrobiology Institute—Virtual Planetary Laboratory Lead Team, USA
- Planetary Environments Laboratory, NASA Goddard Space Flight Center, Greenbelt, Maryland
| | - Russell Deitrick
- Astronomy Department, University of Washington, Seattle, Washington
- NASA Astrobiology Institute—Virtual Planetary Laboratory Lead Team, USA
| | - Rory K. Barnes
- Astronomy Department, University of Washington, Seattle, Washington
- NASA Astrobiology Institute—Virtual Planetary Laboratory Lead Team, USA
| | - David P. Fleming
- Astronomy Department, University of Washington, Seattle, Washington
- NASA Astrobiology Institute—Virtual Planetary Laboratory Lead Team, USA
| | - Rodrigo Luger
- Astronomy Department, University of Washington, Seattle, Washington
- NASA Astrobiology Institute—Virtual Planetary Laboratory Lead Team, USA
| | - Peter E. Driscoll
- NASA Astrobiology Institute—Virtual Planetary Laboratory Lead Team, USA
- Department of Terrestrial Magnetism, Carnegie Institution for Science, Washington, DC
| | - Thomas R. Quinn
- Astronomy Department, University of Washington, Seattle, Washington
- NASA Astrobiology Institute—Virtual Planetary Laboratory Lead Team, USA
| | - David Crisp
- NASA Astrobiology Institute—Virtual Planetary Laboratory Lead Team, USA
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California
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14
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Halevy I, Bachan A. The geologic history of seawater pH. Science 2017; 355:1069-1071. [DOI: 10.1126/science.aal4151] [Citation(s) in RCA: 161] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 02/14/2017] [Indexed: 11/02/2022]
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15
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Constraints on Climate and Habitability for Earth-like Exoplanets Determined from a General Circulation Model. ACTA ACUST UNITED AC 2017. [DOI: 10.3847/1538-4357/aa5ffc] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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16
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Gebauer S, Grenfell JL, Stock JW, Lehmann R, Godolt M, von Paris P, Rauer H. Evolution of Earth-like Extrasolar Planetary Atmospheres: Assessing the Atmospheres and Biospheres of Early Earth Analog Planets with a Coupled Atmosphere Biogeochemical Model. ASTROBIOLOGY 2017; 17:27-54. [PMID: 28103105 DOI: 10.1089/ast.2015.1384] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Understanding the evolution of Earth and potentially habitable Earth-like worlds is essential to fathom our origin in the Universe. The search for Earth-like planets in the habitable zone and investigation of their atmospheres with climate and photochemical models is a central focus in exoplanetary science. Taking the evolution of Earth as a reference for Earth-like planets, a central scientific goal is to understand what the interactions were between atmosphere, geology, and biology on early Earth. The Great Oxidation Event in Earth's history was certainly caused by their interplay, but the origin and controlling processes of this occurrence are not well understood, the study of which will require interdisciplinary, coupled models. In this work, we present results from our newly developed Coupled Atmosphere Biogeochemistry model in which atmospheric O2 concentrations are fixed to values inferred by geological evidence. Applying a unique tool (Pathway Analysis Program), ours is the first quantitative analysis of catalytic cycles that governed O2 in early Earth's atmosphere near the Great Oxidation Event. Complicated oxidation pathways play a key role in destroying O2, whereas in the upper atmosphere, most O2 is formed abiotically via CO2 photolysis. The O2 bistability found by Goldblatt et al. ( 2006 ) is not observed in our calculations likely due to our detailed CH4 oxidation scheme. We calculate increased CH4 with increasing O2 during the Great Oxidation Event. For a given atmospheric surface flux, different atmospheric states are possible; however, the net primary productivity of the biosphere that produces O2 is unique. Mixing, CH4 fluxes, ocean solubility, and mantle/crust properties strongly affect net primary productivity and surface O2 fluxes. Regarding exoplanets, different "states" of O2 could exist for similar biomass output. Strong geological activity could lead to false negatives for life (since our analysis suggests that reducing gases remove O2 that masks its biosphere over a wide range of conditions). Key Words: Early Earth-Proterozoic-Archean-Oxygen-Atmosphere-Biogeochemistry-Photochemistry-Biosignatures-Earth-like planets. Astrobiology 16, 27-54.
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Affiliation(s)
- S Gebauer
- 1 Zentrum für Astronomie und Astrophysik (ZAA), Technische Universität Berlin (TUB) , Berlin, Germany
- 2 Institut für Planetenforschung (PF) , Deutsches Zentrum für Luft- und Raumfahrt (DLR), Berlin, Germany
| | - J L Grenfell
- 2 Institut für Planetenforschung (PF) , Deutsches Zentrum für Luft- und Raumfahrt (DLR), Berlin, Germany
| | - J W Stock
- 3 Instituto de Astrofísica de Andalucía-CSIC , Granada, Spain
| | - R Lehmann
- 4 Alfred-Wegener Institut Helmholtz-Zentrum für Polar- und Meeresforschung , Potsdam, Germany
| | - M Godolt
- 2 Institut für Planetenforschung (PF) , Deutsches Zentrum für Luft- und Raumfahrt (DLR), Berlin, Germany
| | - P von Paris
- 5 Université de Bordeaux , LAB, UMR 5804, Floirac, France
- 6 CNRS, LAB , UMR 5804, Floirac, France
| | - H Rauer
- 1 Zentrum für Astronomie und Astrophysik (ZAA), Technische Universität Berlin (TUB) , Berlin, Germany
- 2 Institut für Planetenforschung (PF) , Deutsches Zentrum für Luft- und Raumfahrt (DLR), Berlin, Germany
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17
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Arney G, Domagal-Goldman SD, Meadows VS, Wolf ET, Schwieterman E, Charnay B, Claire M, Hébrard E, Trainer MG. The Pale Orange Dot: The Spectrum and Habitability of Hazy Archean Earth. ASTROBIOLOGY 2016; 16:873-899. [PMID: 27792417 PMCID: PMC5148108 DOI: 10.1089/ast.2015.1422] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 07/13/2016] [Indexed: 05/21/2023]
Abstract
Recognizing whether a planet can support life is a primary goal of future exoplanet spectral characterization missions, but past research on habitability assessment has largely ignored the vastly different conditions that have existed in our planet's long habitable history. This study presents simulations of a habitable yet dramatically different phase of Earth's history, when the atmosphere contained a Titan-like, organic-rich haze. Prior work has claimed a haze-rich Archean Earth (3.8-2.5 billion years ago) would be frozen due to the haze's cooling effects. However, no previous studies have self-consistently taken into account climate, photochemistry, and fractal hazes. Here, we demonstrate using coupled climate-photochemical-microphysical simulations that hazes can cool the planet's surface by about 20 K, but habitable conditions with liquid surface water could be maintained with a relatively thick haze layer (τ ∼ 5 at 200 nm) even with the fainter young Sun. We find that optically thicker hazes are self-limiting due to their self-shielding properties, preventing catastrophic cooling of the planet. Hazes may even enhance planetary habitability through UV shielding, reducing surface UV flux by about 97% compared to a haze-free planet and potentially allowing survival of land-based organisms 2.7-2.6 billion years ago. The broad UV absorption signature produced by this haze may be visible across interstellar distances, allowing characterization of similar hazy exoplanets. The haze in Archean Earth's atmosphere was strongly dependent on biologically produced methane, and we propose that hydrocarbon haze may be a novel type of spectral biosignature on planets with substantial levels of CO2. Hazy Archean Earth is the most alien world for which we have geochemical constraints on environmental conditions, providing a useful analogue for similar habitable, anoxic exoplanets. Key Words: Haze-Archean Earth-Exoplanets-Spectra-Biosignatures-Planetary habitability. Astrobiology 16, 873-899.
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Affiliation(s)
- Giada Arney
- Astronomy Department, University of Washington, Seattle, Washington, USA
- NASA Astrobiology Institute Virtual Planetary Laboratory, University of Washington, Seattle, Washington, USA
- Astrobiology Program, University of Washington, Seattle, Washington, USA
- Now at: NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
- Now at: NASA Postdoctoral Program, Universities Space Research Association, Columbia, Maryland, USA
| | - Shawn D. Domagal-Goldman
- NASA Astrobiology Institute Virtual Planetary Laboratory, University of Washington, Seattle, Washington, USA
- NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
| | - Victoria S. Meadows
- Astronomy Department, University of Washington, Seattle, Washington, USA
- NASA Astrobiology Institute Virtual Planetary Laboratory, University of Washington, Seattle, Washington, USA
- Astrobiology Program, University of Washington, Seattle, Washington, USA
| | - Eric T. Wolf
- Department of Atmospheric and Oceanic Sciences, Laboratory for Atmospheric and Space Physics, University of Colorado at Boulder, Boulder, Colorado, USA
| | - Edward Schwieterman
- Astronomy Department, University of Washington, Seattle, Washington, USA
- NASA Astrobiology Institute Virtual Planetary Laboratory, University of Washington, Seattle, Washington, USA
- Astrobiology Program, University of Washington, Seattle, Washington, USA
- Now at: NASA Postdoctoral Program, Universities Space Research Association, Columbia, Maryland, USA
- Now at: University of California at Riverside, Riverside, California, USA
- Blue Marble Institute of Science, Seattle, Washington, USA
| | - Benjamin Charnay
- Astronomy Department, University of Washington, Seattle, Washington, USA
- NASA Astrobiology Institute Virtual Planetary Laboratory, University of Washington, Seattle, Washington, USA
- Astrobiology Program, University of Washington, Seattle, Washington, USA
- Now at: Paris-Meudon Observatory, Paris, France
| | - Mark Claire
- NASA Astrobiology Institute Virtual Planetary Laboratory, University of Washington, Seattle, Washington, USA
- Blue Marble Institute of Science, Seattle, Washington, USA
- Department of Earth and Environmental Sciences, University of St Andrews, St Andrews, UK
| | - Eric Hébrard
- NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
- University of Exeter, Exeter, Devon, UK
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18
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Popp M, Schmidt H, Marotzke J. Transition to a Moist Greenhouse with CO2 and solar forcing. Nat Commun 2016; 7:10627. [PMID: 26859279 PMCID: PMC4748134 DOI: 10.1038/ncomms10627] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 01/05/2016] [Indexed: 11/09/2022] Open
Abstract
Water-rich planets such as Earth are expected to become eventually uninhabitable, because liquid water turns unstable at the surface as temperatures increase with solar luminosity. Whether a large increase of atmospheric concentrations of greenhouse gases such as CO2 could also destroy the habitability of water-rich planets has remained unclear. Here we show with three-dimensional aqua-planet simulations that CO2-induced forcing as readily destabilizes the climate as does solar forcing. The climate instability is caused by a positive cloud feedback and leads to a new steady state with global-mean sea-surface temperatures above 330 K. The upper atmosphere is considerably moister in this warm state than in the reference climate, implying that the planet would be subject to substantial loss of water to space. For some elevated CO2 or solar forcings, we find both cold and warm equilibrium states, implying that the climate transition cannot be reversed by removing the additional forcing.
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Affiliation(s)
- Max Popp
- Max Planck Institute for Meteorology, Bundesstrasse 53, Hamburg 20146, Germany
- Program in Atmospheric and Oceanic Sciences, Princeton University, 300 Forrestal Road, Sayre Hall, Princeton, New Jersey 08544, USA
- Present address: NOAA's Geophysical Fluid Dynamics Laboratory, Princeton, New Jersey, USA
| | - Hauke Schmidt
- Max Planck Institute for Meteorology, Bundesstrasse 53, Hamburg 20146, Germany
| | - Jochem Marotzke
- Max Planck Institute for Meteorology, Bundesstrasse 53, Hamburg 20146, Germany
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19
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Rapf RJ, Vaida V. Sunlight as an energetic driver in the synthesis of molecules necessary for life. Phys Chem Chem Phys 2016; 18:20067-84. [DOI: 10.1039/c6cp00980h] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
This review considers how photochemistry and sunlight-driven reactions can abiotically generate prebiotic molecules necessary for the evolution of life.
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Affiliation(s)
- Rebecca J. Rapf
- Department of Chemistry and Biochemistry
- CIRES
- University of Colorado at Boulder
- Boulder
- USA
| | - Veronica Vaida
- Department of Chemistry and Biochemistry
- CIRES
- University of Colorado at Boulder
- Boulder
- USA
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20
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Foley BJ. THE ROLE OF PLATE TECTONIC–CLIMATE COUPLING AND EXPOSED LAND AREA IN THE DEVELOPMENT OF HABITABLE CLIMATES ON ROCKY PLANETS. ACTA ACUST UNITED AC 2015. [DOI: 10.1088/0004-637x/812/1/36] [Citation(s) in RCA: 109] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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21
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Pecoits E, Smith ML, Catling DC, Philippot P, Kappler A, Konhauser KO. Atmospheric hydrogen peroxide and Eoarchean iron formations. GEOBIOLOGY 2015; 13:1-14. [PMID: 25324177 DOI: 10.1111/gbi.12116] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 09/15/2014] [Indexed: 06/04/2023]
Abstract
It is widely accepted that photosynthetic bacteria played a crucial role in Fe(II) oxidation and the precipitation of iron formations (IF) during the Late Archean-Early Paleoproterozoic (2.7-2.4 Ga). It is less clear whether microbes similarly caused the deposition of the oldest IF at ca. 3.8 Ga, which would imply photosynthesis having already evolved by that time. Abiological alternatives, such as the direct oxidation of dissolved Fe(II) by ultraviolet radiation may have occurred, but its importance has been discounted in environments where the injection of high concentrations of dissolved iron directly into the photic zone led to chemical precipitation reactions that overwhelmed photooxidation rates. However, an outstanding possibility remains with respect to photochemical reactions occurring in the atmosphere that might generate hydrogen peroxide (H2 O2 ), a recognized strong oxidant for ferrous iron. Here, we modeled the amount of H2 O2 that could be produced in an Eoarchean atmosphere using updated solar fluxes and plausible CO2 , O2 , and CH4 mixing ratios. Irrespective of the atmospheric simulations, the upper limit of H2 O2 rainout was calculated to be <10(6) molecules cm(-2) s(-1) . Using conservative Fe(III) sedimentation rates predicted for submarine hydrothermal settings in the Eoarchean, we demonstrate that the flux of H2 O2 was insufficient by several orders of magnitude to account for IF deposition (requiring ~10(11) H2 O2 molecules cm(-2) s(-1) ). This finding further constrains the plausible Fe(II) oxidation mechanisms in Eoarchean seawater, leaving, in our opinion, anoxygenic phototrophic Fe(II)-oxidizing micro-organisms the most likely mechanism responsible for Earth's oldest IF.
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Affiliation(s)
- E Pecoits
- Equipe Géobiosphère, Institut de Physique du Globe-Sorbonne Paris Cité, Université Paris Diderot, CNRS, Paris, France; Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta, Canada
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22
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Wolf ET, Toon OB. Controls on the Archean climate system investigated with a global climate model. ASTROBIOLOGY 2014; 14:241-253. [PMID: 24621308 DOI: 10.1089/ast.2013.1112] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The most obvious means of resolving the faint young Sun paradox is to invoke large quantities of greenhouse gases, namely, CO2 and CH4. However, numerous changes to the Archean climate system have been suggested that may have yielded additional warming, thus easing the required greenhouse gas burden. Here, we use a three-dimensional climate model to examine some of the factors that controlled Archean climate. We examine changes to Earth's rotation rate, surface albedo, cloud properties, and total atmospheric pressure following proposals from the recent literature. While the effects of increased planetary rotation rate on surface temperature are insignificant, plausible changes to the surface albedo, cloud droplet number concentrations, and atmospheric nitrogen inventory may each impart global mean warming of 3-7 K. While none of these changes present a singular solution to the faint young Sun paradox, a combination can have a large impact on climate. Global mean surface temperatures at or above 288 K could easily have been maintained throughout the entirety of the Archean if plausible changes to clouds, surface albedo, and nitrogen content occurred.
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Affiliation(s)
- E T Wolf
- Department of Atmospheric and Oceanic Sciences, Laboratory for Atmospheric and Space Physics, University of Colorado , Boulder, Colorado
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23
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Leconte J, Forget F, Charnay B, Wordsworth R, Pottier A. Increased insolation threshold for runaway greenhouse processes on Earth-like planets. Nature 2013; 504:268-71. [DOI: 10.1038/nature12827] [Citation(s) in RCA: 206] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Accepted: 11/04/2013] [Indexed: 11/10/2022]
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