Since we know how the Bible ends, do things like protecting endangered animals, saving the trees, and the watching the condition of the ozone layer really matter?
The Bible vividly describes the end of this world as we know it, but that is no excuse for not being good stewards of God's creation. He has given us a home here on earth and, in fact, He says that if we don't do our job in praising Him, even the rocks will cry out in worship to God their Creator. This means that God's creation, just by existing, is worship of His name.
God gave us dominion over the land and the animals. Genesis tells us that God said, "Be fruitful and increase in number; fill the earth and subdue it. Rule over the fish of the sea and the birds of the air and over every living creature that moves on the ground" (Gen. 1:28). This means that we are to exercise leadership over the resources that God has given us.
Furthermore, Genesis 2:15 says, "The Lord God took the man and put him in the Garden of Eden to work it and take care of it." This charge was outlined right from the beginning: Take care of God's creation.
We cannot take a defeatist attitude and just let things fall apart. Each of us has a responsibility to one another to care for the world around us. True, we do know how the story ends; but we are to live it out to completion, caring for all that God has blessed us with and preparing for His coming by spreading the Word.