Greenopia is an online directory that purports to help people make 'green' choices in their every day living. They have just posted a rating of 30 pet foods, with the most green being Karma (made by Natura brands) and Raw Advantage.
I found it very difficult to determine how they rated the products as the website doesn't appear to post their criteria. Pet food Industry magazine reports:
"Greenopia collected data from manufacturers and independent sources about each brand's ingredients, packaging, sustainability reporting, supply chain, animal testing policies and green building design. Companies were given additional points for their adoption of environmental initiatives. One-third of the brands evaluated earned zero-leaf ratings, revealing them to be below Greenopia's minimum green threshold."
You can see the entire listing here: http://www.greenopia.com/LA/petfoods_search.aspx?category=PetFoods&Listpage=0&input=Name%20or%20product&subcategory=None