I enjoy a sport, which I have made into a profession and which I know is making a difference in Africa. How many people you know can actually say that they can measure the difference they have made, or count the animals that they actively conserve.
I know I can.
As far as where I get my justification, I get it from the ultimate authority, God himself. Genesis 9:2-3 After the flood, God told Noah: "The fear and dread of you will fall on all the beasts of the earth and all the birds of the air, upon every creature that moves along the ground, and upon all the fish of the sea; they are given into your hands. Everything that lives and moves will be food for you. Just as I gave you the green plants, I now give you everything."