This year could be the year in which world leaders finally pass a binding climate change treaty and citizens and corporations divest from fossil fuels and both politicians and consumers put sustainability and renewable energy solutions where their mouths are. It turns out that consumers are fiercely loyal to brands that do that.

While many corporations seem to be looking to find ways to do business in a sustainable way, of the 550 brands included in this years Customer Loyalty Engagement Index, a survey of 36,000 men and women, 18-65 years of age, from the 9 U.S. Census Regions, here are the top-50 brands deemed authentically and resolutely green by their own customers. They are presented alphabetically since environmental demands and consumer expectations are category-specific.

For brands, simply playing the environmental awareness card as part of a CSR or PR campaign isnt an actual option anymore. Brands have to do it in ways that meaningfully support a sustainable future that is palpable to the consumer. And as the number of companies trying to co-opt environmental issues for their brands has grown, so too have the number of skeptical consumers. Most consumers have heard such promises before and  in the face of increased expectations  have begun to demand authenticity. They understand that the technology exists, and more and more consumers feel that all brands need is the will to make it so. To borrow a phrase from the Wizard of Oz, consumers want brands to be morally, ethically, spiritually, physically, positively, absolutely, undeniably and reliably green.

Today is the 45th anniversary of Earth Day. Its celebration comes with the hopes of tens of millions of people that this is the moment in history where equilibrium between sustainability and economic growth is realized. According to the experts, to do that, everyone  including brands  have to commit to a low carbon future.

Im the founder/president of Brand Keys, Inc. the NY-based brand loyalty and customer engagement consultancy. Ive pioneered work in loyalty, emotional engagement and predictive metrics creating the Customer Loyalty Engagement Index (examining 83 categories and 598 brands), and the Sports Fan and Womens Wear Daily Fashion Brand Indices. My first book, Predicting Market Success, provided a 21st century paradigm for loyalty. My current book, The Certainty Principle, deals with engagement in a more complex, cross-channel marketplace. Im a two-time winner of the Advertising Research Foundations Research Innovator award, and in 2008, New York Universitys communication school declared me the most-quoted brand consultant in the United States. In 2012 we introduced the Digital Platform GPS, a review of 14 digital platforms and their engagement effects in 83 B2C and B2B categories. I can be reached at robertp@brandkeys.com.