From the Preamble to the IWW Constitution
Between these two classes a struggle must go on until the workers of the world organize as a class, take possession of the means of production, abolish the wage system, and live in harmony with the Earth.
This last section, in boldfaced, was added to the Preamble in 1991, by a referendum vote of the IWW membership, but it was proposed by Fellow Workers Judi Bari, Jess Grant, and Utah Phillips following Redwood Summer, which was a coalition effort organized by northwestern California chapters of Earth First!, the IWW, and Seeds of Peace.
While some may question the relevance of this clause, it cannot be denied that in addition to wage slavery and the exploitation of the working class by the employing class, Capitalism is also inherently destructive to life on Earth itself due to its process of externalizing social costs. Resource depletion, the destruction of biomass and habitat, waste, and pollution are the ultimate result of such "externalization", but -- since all life is interdependent -- in nature there is no such thing as externalization. Capitalism merely shifts the burden of its exploitation of the Earth onto the working class!
Not only is this process exploitative of both the working class and the earth, it is genocidal and must be stopped.
Naturally (no pun intended), this requires not only that the workers take possession of the machinery of production, but also that the working class rethink production entirely!
Both Judi Bari and Jess Grant offered thoughts on this process. While it must be emphasized that neither of the following texts are official IWW literature (and Bari's piece was actually directed at Earth First!, though she was an IWW member when she conceived it) both offer a starting point for the transformations that need to occur if humanity is to survive, let alone build the new society within the shell of the old:
Beyond that, though the group is unofficial, some IWW members have taken it upon themselves to organize an Ecological Unionism Caucus (or Environmental Unionism Caucus), which any dues paying IWW member may join, to help define and clarify these positions. For more information, visit ecology.iww.org.