Temperature on earth remains within a range suitable, for life because the biosphere has a natural insulating blanket.
The atmospheric gases such as, carbon dioxides, methane, water vapor, and a few other gases trap heat energy to maintain earth’s temperature range.
In addition, these gases function like the glass windows of green house. The glass keeps the green house plants warm; these gases trap the heat energy of sunlight inside earth’s atmosphere.
Thus, the natural condition in which heat is retained by this layer of green house gases is called the green house effect.