I don't know, I'd tend to side with Ed on this -- it stands to reason that even if an issue goes beyond just your audience you are likely to appeal to them specifically. Then that audience is more likely to listen to you. And it doesn't immediately follow that you exclude all others from having a role just because you haven't specifically mentioned them. "As Christians, we have a duty to give charitably..." but then everyone else ought to help other people as and when they are able.
A more serious objection, I think, would be the question: if Christians have a duty to act as stewards of the Earth, why have they not been doing so for most of the last 2,000 years? Or at least, if they have been trying that it's not been all that effective, has it? The Earth is, at least on the surface, unrecognisable from what it used to be. England was once almost one big forest -- the trees are all gone now, most of that damage being done in the early part of the last millennium. Seems a bit late then, no?
Fracking seems to cause environmental problems to some extent, but no more than many other things that have gone on virtually unchecked -- including deforestation and extraction of coal, metals, other fossil fuels, industrial levels of fishing, industry as a whole polluting the atmosphere... where is the Church's "stewardship of the Earth" on these issues?