Susceptibility of the early Earth to irreversible glaciation caused by carbon ice clouds

The warming of the Earth soon after it formed probably prevented the onset of an interminable glacial climate due to highly reflective carbon dioxide (CO2) clouds and the Sun's much less intense output of heat at the time. The suggestion that an early greenhouse effect stabilized the Earth's climate does not explain why the oceans failed to freeze before the greenhouse gases could accumulate. Paleoclimatic simulations indicate that Earth may have narrowly escaped being rendered uninhabitable by world-wide glaciation thanks to either internal heat or additional greenhouse gases.