The concept of "mother nature" is not biblical. God created the heavens and the earth.
The concept of open heart surgery isn't biblical, either. God meant for clogged arteries to kill you dead as a hammer. Ditto insulin, antibiotics and other drugs, and electricity and radio. None of those are biblical concepts, either. Perhaps your bible isn't the Final and Ultimate Authority on Everything you insist on framing it as.
I don't have a problem with caring for what God gave us,
Good.
but the environment shouldn't be a primary focus for Christians, in my opinion. God gave us the earth ...
And if you believe that, then you also believe that Earth was given to Man as a marvelous, wonderful gift. Is the proper response to being given a priceless gift to aggressively tear it up, to shit in it and indifferently set it on fire so that no one who comes after you will ever get to use it?
He sustains it, protects it
Seems like He really isn't doing much to protect it, since He's apparently perfectly happy allowing us to do anything we want to it. But that's neither here nor there.
and will ultimately destroy it.
Well, good for God. Does He need our help to wreck it? Then let Him do it if He wants.
This earth is not our home. Nothing is going to happen to this earth that isn't part of God's will or ultimate plan, no matter how many gasses I emit or plastic bottles I throw in my garbage can. I'm waiting for the new heaven and the new earth.
Former secretary of the interior James Watt apparently agrees with you.
If you actually believe this, then no one sane needs to allow you or anyone like you the right to make decisions that affect large numbers of people other than yourself. Why would ANY self-respecting deity give ANYTHING to someone like you after you thoughtlessly destroyed what he already gave you?