I would begin by making a case for environmental responsibility. A great way to show our love of the creator is to show our love for his creation. I often make the conparison that if your best friend gave you their best work of art, as a token of your friendship, and instead of mounting this tapestry in a prominent place and displaying it for all to see, you layed it at the foot of your front door for people to wipe their feet on when they enter your house. When your friend comes over and sees what you have done, she is not going to be very impressed.
The Catechism of the Catholic Church 2415 to 2418 discusses
Respect for the integrity of creation, which could be quoted and expanded to explain the Church's view that we need to care for the earth and be responsible stewards.
In Genesis 1:28, God commanded man and woman to go out into the world:
God blessed them and said to them, "Be fruitful and multiply, and fill the earth and subdue it; have dominion over the fish of the sea and of the birds of the airand every other living thing that moves upon the earth."
Part of having dominion over the earth is taking care of it. With rights come responsibilities...
Then I'd talk about other things that are good such as the desire to build up a strong economy for a country or even the world. "The development of economic activity and growth in production are meant to provide for the needs of human beings." (Catechism 2426). Good healthy economies, therefore, help to better provide for the needs of all people - especially the poor.
In Alberta, the energy industry is a key part of the economy, and harvesting the oil sands is a controversial environmental issue. The Bishop of St. Paul wrote a letter about concerns he had about the massive developments and concerns he had for the enviroment that could be cited:
http://www.dioceseofstpaul.ca/index....=135&Itemid=11
Then you could talk about the competing goods of both environmentalism and the economy. Problems occur when either good is completely ignored. Describe these. We need to find a balance between the two.
PM me if you have further questions. I will check my box before bed.