The document for this is found here.
For Christians skeptical of 'ecumenism' it is worth noting we share the planet with everyone else made in God's image and in the Spirit of Jeremiah 29:6-8 should be working for the good of the planet and the people with whom we share it. This is to say nothing of acting as Good Samaritans to protect the food stores, water reserves and purifies, buffers against land slides, etc of the world's poor. A casual glance at Psalm 104 will also show that the biodiversity of creation is a hymn of praise to God, and hence our preservation of it. To be truly Christian is to be truly 'green' without a hint of paganism.