Freezing. The greenhouse effect is the way how earth is kept warm , as the heat radiation is trapped through the gasses ( gasses reflect the radiation back to earth) without the green house effect, the earth I assume would be all "iced up"and " bare and bold" up, and life (as we know it ) would not survive ( some others forms of life may take place but we never know...)
Personal opinion , free to accept other ideas .
The most powerful approach to isolating a single mutant from a population of billions is positive selection.
50/50 shot of recessive or dominate phenotype
