This is what it comes down to.
For those of us who find ourselves in positions of power, there is exactly one right course. There is only one acceptable use of power. We must protect those who cannot protect themselves. We must help those in need. We must never, never, use our might to harm those weaker than ourselves. This is our unshakable obligation. This is the one just use for strength.
And that is exactly where we have failed as a species. That is why the damage we have done to the biosphere is so wrong. Forget that we have plundered and destroyed the pristine and the beautiful, forget even that we are endangering our own children: the havoc we wreak on the planet is wrong because we chose to use our power in the wrong way. We could have done better, but we didn’t — we chose not to.
We are the stewards of the Earth. This is not because an omniscient creator-god made us so, gave us dominion over the animals, but because it is humandkind, alone among creatures, with the incredible power to change, pollute, pillage, and destroy the world. No one can deny that we posses this power. We are, so far, incredibly powerful. Alone among species, we control our fate, and the fate of all of creation. We can and we do overpower non-human animals. We can and we do destroy ecosystems, contaminate water and air supplies, turn forests into deserts.
This makes us the stewards of the Earth. We must be the stewards of the planet, for the only alternative is to be its oppressors. We can be caretakers or we can be despots.
There is, of course, exactly one right choice. What is the right choice when an adult encounters an infant? What is the right choice when a child plays with a kitten? When one comes upon a person who is badly hurt?
We must be guardians. If we fail in this regard, we have failed as human beings, exactly as parent who kills a child has failed as a father or mother.
Edited to add on: And so power, in and of itself, isn’t a bad thing. Power can be an incredible force for justice, when used that way.
That’s not to say that unjust power imbalances — like say, between genders or races — are ever okay, or can ever be a force of good. But those that are unavoidable, such as the gap between parents and children, or between people and fish, can be very good. I don’t believe we will ever have egalitarianism amongst species, but I don’t believe we have to in order to have liberty and justice for all.