The Pope spoke about Creation during his homily. He asked Christians to not dominate the planet but instead work to preserve it.
"When we hear that people organize to take care of the planet, we sometimes say: We aren't enviromentalists. We are Christians! It isn't our concern. That was our response to the 'first Creation' of God. But it is our responsibility! A Christian that does not care for Creation, that does not make it grow, is a Christian who doesn't care about the work of God; that work born from the love of God for us. And this is the first answer to the first Creation: to care for Creation, to make it grow."
He further explained that Jesus, in becoming man, held a second Creation because the first was ruined by sin.
COMPLETE POPE HOMILY
(Source: Vatican Radio)
"God works, continues to work, and we can ask ourselves how we should respond to this creation of God, which is born of love, because he works through love. In the 'first creation' we must respond with the responsibility that the Lord gives us: 'The earth is yours, take it forward; let it grow '. Even for us there is a responsibility to nurture the Earth, to nurture Creation, to keep it and make it grow according to its laws. We are the lords of creation, not its masters. "
"When we hear that people have meetings about how to preserve creation, we can say: 'No, they are the greens!' No, they are not the greens! This is the Christian! This is 'our response to the' first creation 'of God. And' our responsibility. A Christian who does not protect Creation, who does not let it grow, is a Christian who does not care about the work of God, that work that was born from the love of God for us. And this is the first response to the first creation: protect creation, make it grow. "
"And all three are involved in this creation, in this re-creation, in this perseverance in re-creation. And to all three of them our response is: to preserve and nurture Creation, let ourselves be reconciled with Jesus, with God in Jesus Christ, every day, and do not be grieved by the Holy Spirit, not drive it away: he is the host of our hearts, he who accompanies us, he who makes us grow. "