What is the Catholics feelings about their moral duty towards the environment
It honestly depends on which Catholic you ask. A common biblical quote used when speaking about the environment is Genesis 1:28 which says, "God blessed them and said to them, 'Be fruitful and increase in number; fill the earth and subdue it. Rule overthe fish in the sea and the birds in the sky and over every living creature that moves on the ground.'" Another less popular quote is from Psalms 115:16, which says, "The highest heavens belong to the Lord, but the earth he has given to mankind."
People who seek to justify certain forms of animal cruelty or stripping the earth of its resources usually use these quotes to say that God has given man the power to do whatever he wants with the earth, as it was all created for man. Because humans have dominion over the earth and are allowed to "subdue it," they are perfectly in their rights to take anything they want from it. However, on the other side, people use this quote to say that God gave us the earth as a gift, and as we hold authority over it, we have a responsibility to take care of it.
If you want to know the official stance of the Catholic church on environmental issues, you should look at what the Vatican has been saying on the subject, as the Pope and other clergymen residing in the Vatican are the "face" of Catholicism. In 2008, the Vatican revisited the seven deadly sins and decided to give them a modern update, and in this update they included damaging the environment as a sin. This year, the new Pope has been trying to repair the tenuous relationship between religion and science, and in his inaugural speech he said, "Let us be "protectors" of creation, protectors of God's plan inscribed in nature, protectors of one another and the environment."