Science is finally catching up with the Bible (again) and realizing just how special this planet is (what creationists have been saying for many years). It’s not just “Two factors” (as Carl Sagan famously proclaimed) that determine whether a planet can likely host life, it’s a combination of MANY factors, most of which are little understood.
The linked article proposes (much to Al Gore’s chagrin) that a “Balance” of greenhouse gases is necessary in order for there to be some form of energy retention in the atmosphere. But too much, and the ice will not just melt into oceans, it will evaporate away!
My take on that: Our understanding is still very poor as to how all the factors work together. We only know that in certain cases, like our earth, there is a balance, not just of atmospheric gases, but in the tilt of the earth, the moon, the tides, the molten liquid core providing heat to the oceans, and so on.
“The finding suggests the number of potentially habitable planets and moons may be less than previously estimated, especially for small icy planets and icy moons,” Yang told Space.com.
I would say far less.