Believe it or not, not all wines are the same level of green. In fact, there is a good amount of variance in the level of sustainability and green practices that wineries use.
Instead of going out and doing the research for you, Greenopia has done the work for you. The web site has ranked wineries based on growing practices, efficiency of buildings, transportation, and packaging. Greenopia rates the "greenness," or environmental impact, of companies in a number of fields, including airlines, auto makers, fast food restaurants, and others.
For more information on which wines are the greenest, check out the ratings on the Greenopia web site.