I think this blog post is pretty interesting. Its really short, and presents a pretty valid (and therefore humorous) point about how celebrating Earth Day goes against the Darwinistic worldview, rather it only makes sense if you are trying to protect something you are given. Which, would be a theistic worldview.
Earth Day for Evolutionists (2007)
“Therefore, since we are surrounded by such a great cloud of witnesses, let us throw off everything that hinders and the sin that so easily entangles, and let us run with perseverance the race marked out for us. Let us fix our eyes on Jesus, the author and perfecter of our faith, who for the joy set before him endured the cross, scorning its shame, and sat down at the right hand of the throne of God.” Hebrews 12:1-2
Earth Day: Being Green, Trendy, and Advocating for a Cause