Dean, Mostly no. But 'Life as we know it' is a very relative term. The concept of 'necessary for life' is very self surving for us as we are the dominate life here and to us the atmosphere and climate of Earth is necessary. One thing about life, it always adapts to it environment. There are organisms thriving around underwater geo-thermal vents where the temperature is past boiling and there is more sulpher than oxygen, wich is arguable that is more hostile than some other extrateresstial bodies. There is only onw way to know for sure.