In this article on the History of Earth Day, it becomes clear that the strategy of environmental organizations to engage with corporations to support climate change legislation in the U.S. did not work in the absence of a grassroots movement. It's not about messaging. It is about exercising political power through democratic structures - sounds naive but there doesn't appear to be a better substitute.

http://www.newyorker.com/arts/critics/atlarge/2013/04/15/130415crat_atlarge_lemann