Hobbes, your 2 points above are certainly valid environmental issues, but I'm afraid they only scratch the surface of deleterious human impacts. There are myriad forms of wildlife disturbance that have to be considered- from humans as disease vectors, vectors for invasive plant introduction, agents of direct and indirect "take" of rare, threatened and endangered species, and a bloody long host of other wildlife habitat disturbances, and general ecological impacts that need to be considered.... Alright, then this leaves #1, environmental impact, as the primary core objective to be addressed. Environmental impact is fairly trivial to measure, since it's completely objective and backed by decades of proven, well tested science...
OK, back to environmental impact. Typically, in order to reduce and simplify what are in many cases extremely complex topics, there are two standard considerations utilized to avoid the dreaded "matrix of unmanageable proportions". And these are, prevention vs mitigation. Next question: what exactly is being proposed that is attempting to either prevent and/or mitigate?
Glad you asked; in order:
1. Human waste
2. Compression (physical features, undergrowth, meadows, alpine flora, plant litter, etc)
IMO, anyone advocating reductions in access and traffic flow/volume would best be served by attacking these two key points of vulnerability.
And as for this statement above, I blanch to read it-- if only it were true! Besides the fact that so many environmental impacts are, in fact, dreadfully complex, and difficult to quantify, there is a second ugly head to this monster- called "advocacy science." All biologists are not as pure as the driven snow, and some are not above white-washing real environmental impacts, and even fabricating reports that conclude that the impacts are negligible- when they are not!Environmental impact is fairly trivial to measure, since it's completely objective and backed by decades of proven, well tested science...
Where I agree with you entirely is with regard to your overall point that people need to be willing to engage in this messy dialectical process to reach a meaningful consensus. The larger the group of advocates, the more effective will be their position. Sanders said this again and again. Buenos suerte.