Answer: Intrinsic motivation
Explanation:His motivation is stimulated by an inside desire to preserve the environment.
His driven by personal beliefs that saving or protecting the environment is the right thing to do hence he joins an organisation (the Campus chapter Green Peace) that seems to align well with his beliefs of protecting the environment.
When a person has Intrinsic motivation he wants to makes changes that will satisfy that inside desire to see the change .
The person wants to personally impact the change because of their personal belief.