First exploration of the entire runaway greenhouse transition with a 3D global climate model
Authors: Chaverot Guillaume , Bolmont Emeline , Turbet Martin 
Published: September 2022

&lt;p align=&quot;justify&quot;&gt;&lt;span lang=&quot;en-US&quot;&gt;The runaway greenhouse effect [1-4] is a very interesting process for terrestrial planets, studied in particular to determine the inner limit of the Habitable Zone (HZ). &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;This is also important to understand a possible evolution of &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;terrestrial planets &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;from &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;temperate &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;Earth-like planets &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;to&lt;/span&gt; &lt;span lang=&quot;en-US&quot;&gt;magma-ocean&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt; planets. &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;This runway greenhouse transition is &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;usually defined via the calculation of the asymptotic limit of thermal emission of the planet (OLR = Outgoing Longwave Radiation), also called Simpson-Nakajima limit. We have recently shown, using a 1D radiative-convective model, that a radiatively inactive gas such as nitrogen (N2) strongly modifies the OLR of the atmosphere [5] and can extend the inner edge of the HZ towards the host star [6]. We have also highlighted the importance of some physical processes sometimes considered as second order processes &lt;/span&gt; &lt;span lang=&quot;en-US&quot;&gt;(e.g., collisional broadening &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;of water lines)&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;.&lt;/span&gt;&lt;/p&gt;
&lt;p align=&quot;justify&quot;&gt;&lt;span lang=&quot;en-US&quot;&gt;In continuation of this work, we use a 3D&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt; global climate model, LMD-Generic, to study the runaway greenhouse for similar atmospheres. &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;First, we explore the runaway evaporation &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;in a temperature range that goes&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt; beyond every previous work &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;which &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;only &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;studied up to the tipping point &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;[7,8]. &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;We aim to &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;understand the contribution of the inherently three-dimensional processes (e.g. &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;clouds and &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;dynamics) &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;to&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt; the evolution of the atmosphere&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;. &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;We find strong differenc&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;e&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;s with 1D simulations but also with the usual climat&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;e&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt; pattern of temperate stable states. Second, w&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;e also explore the evolution of the atmosphere when the entire water ocean is evaporated, and the convergence on a post-runaway state. This allow us to have a complete overview of the runway transition by linking our results to previous studies of hot &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;Earth-like&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt; planet&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;s&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt; [&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;9&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;].&lt;/span&gt;&lt;/p&gt;
&lt;p lang=&quot;en-US&quot; align=&quot;justify&quot;&gt;&amp;#160;&lt;/p&gt;
&lt;p lang=&quot;en-US&quot;&gt;&amp;#160;&lt;/p&gt;
&lt;p lang=&quot;en-US&quot;&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;
&lt;p lang=&quot;en-US&quot;&gt;[1] Komabayasi, M. 1967, Journal of the Meteorological Society of Japan. Ser. II&lt;/p&gt;
&lt;p lang=&quot;en-US&quot;&gt;[2] Ingersoll, A. 1969, Journal of the Atmospheric Sciences&lt;/p&gt;
&lt;p lang=&quot;en-US&quot;&gt;[3] Nakajima, S., Hayashi, Y.-Y., &amp; Abe, Y. 1992, Journal of the Atmospheric Sciences&lt;/p&gt;
&lt;p lang=&quot;en-US&quot;&gt;[4] Goldblatt, C. &amp; Watson, A. J. 2012, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences&lt;/p&gt;
&lt;p lang=&quot;en-US&quot;&gt;[5] Chaverot G., Bolmont, E., Turbet, M., Leconte, J. 2021, Astronomy &amp; Astrophysics&lt;/p&gt;
&lt;p lang=&quot;en-US&quot;&gt;[6] Goldblatt, C., Robinson, T. D., Zahnle, K. J., &amp; Crisp, D. 2013, Nature Geoscience&lt;/p&gt;
&lt;p&gt;&lt;span lang=&quot;en-US&quot;&gt;[&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;7&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;] Pop, M., Schmidt, H., Marotzke, J. 2016, Nature Communications&lt;/span&gt;&lt;/p&gt;
&lt;p&gt;&lt;span lang=&quot;en-US&quot;&gt;[&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;8&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;] Leconte, J., Forget, F., Charnay, B. et al., 2013, Nature&lt;/span&gt;&lt;/p&gt;
&lt;p&gt;&lt;span lang=&quot;en-US&quot;&gt;[&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;9&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;] Turbet, M., Bolmont, E., Chaverot, G., et al. 2021, Nature&lt;/span&gt;&lt;/p&gt;