Sustainability for Animals
Any morally defensible view of sustainability includes some idea of welfare. That requires us to ask: whose welfare? Thus, even before beginning to work on sustainability, one has to settle the question of the boundaries of moral considerability. Scorse's question implicitly defines sustainability as sustainability of human welfare. A movement focusing only on human welfare implicitly demotes the animal rights movement to the status of a cultural phenomenon, on a par with the local historial society or LARPers (and to be clear, I have nothing against either of those groups). There's no room for recognizing animal rights as a morally righteous quest for justice. People fighting for religious freedom, or immigrants' rights, can remain separate from (and agnostic toward) the question of animal rights, because their issues are irrelevant to animals' welfare. Other movements (such as workers' rights/anti-capitalism) have to answer the animal rights question because the oppression they fight, and the possible solutions to it, are causally linked to animals' welfare. Environmentalism is one step farther -- if animals count, then they are in the same boat (or at least the same kind of boat) as humans.