Borrowing from the tactics of Bill Maher, I propose a New Rule: When putting forth the claim that something is "sustainable," it must be with reference to a comparable item or process that is less so. Go ahead and pretend it's a grammatical rule.
It bothers me to see people claiming sustainability for their product or idea or just something they are just thinking about and happen to like. It's nice that people now seem to care, of course, but greenness claims become difficult to sift through without any frame of reference. Part of this difficulty is that sustainability is, in a great many cases, a concept or rule of thumb rather than a quantitative measure. However, without showing what one's frame of reference is, we can hear words such as "clean coal" and feel justified in sighs of relief despite the fact that, put simply, it is still coal. Burning it still produces carbon dioxide, even if the sulfur content is much lower. The lower sulfur definitely helps reduce air pollution, but once burned, the coal is no longer in a usable form, and we have just added to our collective carbon footprint. Nonrenewable resources that can't be recycled are hardly what I'd call sustainable, at least over the long term.
