Question

What would have happened if there would be no greenhouse effect?

Answer 1

When sunlight enters the earth’s atmosphere they are not absorbed by greenhouse gases since they are short wavelength .These radiations are absorbed by earth and radiates them back (long wavelength) in the atmosphere.
These radiated radiations are absorbed by greenhouse gases. And thus it keeps the earth’s atmosphere warm and makes the life possible on earth. If greenhouse gases were absent then earth’s atmosphere would have been colder and impossible for life to sustain.