Rangeland sustainability: Is science relevant and what is next?

Most, if not all, rangeland research has been about sustainability in some fashion.  But it seems that how we judge sustainability is often based on factors beyond our control-and beyond our typical research and extension.  We usually do a good job of defining limits on ecological, social and economic parameters, but like a lot of other ecological science disciplines, the big picture eludes us and our ability to have the kind of impact we desire is out of reach.  I will talk about this quandry and make some provacative statements intended to encourage disagreement.