Emerald:
Me.
I've been backpacking for pretty damn all 50 years. I've come upon latrine areas by trails and campsites for all of them, and dug up old latrine area on purpose (to lime them, at Scout camps, when they were filled improperly) and by accident, and seen toilet paper that was years old, in ground that was no different than that in the lower areas of the AT. As I've written elsewhere on WB, I've seen places with toilet paper that is years old - and I've seen it - including one of the most beautiful boulder beaches along the Bruce Trail. And I've given it a shot in my own yard in Michigan, which is wonderfully moist black earth, and biologically alive to maximize degradability. The shortest time in that area was several months. In some places, paper has lasted for at least a few years.
Dry areas? Degradation of paper can occur from several things, including fire and abrasion. But in a perfectly dry area, with little or no moisture for bacteria to work their wonders, such as the Sonoran Desert which covers most of Sonora (Mexico), Arizona, New Mexico and Southern Nevada and SE California, paper can (and does) last decades or even centuries.
I'll tell you folks something: I'll stop arguing for packing solid waste and toilet paper out if you can find one respectable public health professional who will say that burying is preferable to packing out. Not merely "acceptable" - since that tends to be what is said by those who realize how many people don't want to do something - but preferable.
As for data, well, this Detroit-born kid doesn't need an MIT data pack to know that gas guzzlers spew out a lot more air pollution than electric hybrids. All I have to do is drive behind one. So you go find that public health pro or that sanitarian who says "Yeah, it's much better to bury waste and TP than to pack it out and dispose of properly." Until then, I've got my data.
TW