ner_tags: O B-Citation I-Citation I-Citation I-Citation O B-Citation I-Citation O O O O O O O O O O O B-Location I-Location O O O B-Model I-Model O O O O O O O O O O O O O O O O O O O O O O B-Location O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-CelestialObject O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Model I-Model O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Citation I-Citation I-Citation I-Citation I-Citation I-Citation O O O O O O O O O O O O O O O O O O O O B-Citation I-Citation I-Citation I-Citation I-Citation I-Citation O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Model O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O
tokens: ; Pierrehumbert et al. 2011 ; Rose 2015 ). The substellar point in our simulations was located over the pacific ocean. We also tried aquaplanet simulations and achieved similar results. It would be interesting to test whether locating the substellar point over a large land mass such as Asia would significantly affects our results. 5. Conclusions The main conclusions of this paper are as follows. 1. Tidally locked planets will not necessarily exhibit a snowball bifurcation. This is in contrast with planets with Earth-like rotation and orbit, which are required to exhibit a snowball bifurcation except in unrealistic edge cases. 2. The reason tidally locked planets are not required to exhibit a snowball bifurcation is that the insolation increases strongly as the substellar point is approached. 3. Whether a tidally locked planet actually does exhibit a snowball bifurcation depends on the heat transport and ice/ocean albedo contrast. Higher heat transport and a higher ice/ocean albedo contrast both favor a snowball bifurcation. 4. We performed GCM simulations that suggest that realistic tidally locked planets will not exhibit a snowball bifurcation. Although they should tend to have stronger heat transport, the top-of-atmosphere ice/ocean albedo contrast should tend to be smaller. 5. This work suggests that we will not find habitable tidally locked exoplanets with an active carbon cycle in a snowball state. This should be verified with a model incorporating an active carbon cycle. Appendix Artifact of Sea Ice Scheme Interestingly, and in contrast with Lucarini et al. ( 2013 ), we find a small separation between equilibrated states that were initialized from Warm and Cold Starts. The most likely reason Lucarini et al. ( 2013 ) did not observe this separation is that they started their Cold Start simulations from a significantly warmer climate state that was not globally glaciated. To further investigate this issue, we show global mean sea ice concentration for a series of simulations with a stellar flux of 1200 W m −2 and initial conditions representing equilibrated climate states with different amounts of sea ice (Figure 9 ). We find that states started within the apparent separation band are stable, rather than approaching separate stable warm and cold states at the upper and lower ends of the separation band. This means that the separation band actually represents a smeared state, which we can consider a continuum of states rather than two distinct “fixed points” with separate basins of attraction. This is clearly unrelated to a snowball bifurcation and does not alter our interpretation that there is no snowball bifurcation in PlaSim in the tidally locked configuration. Figure 9. Time series of global mean sea ice concentration for a series of simulations at a stellar flux of 1200 W m −2 with different initial conditions. This plot demonstrates that the solution is a continuum of states rather than two distinct fixed points. By further