The possible "end of silence" caused by our work and travels is not just an abstract question meant to torment the most intrepid backwoods travelers among us.

According to Tingley, "That sort of human din, studies are beginning to suggest, is imperiling habitat - in Denali as well as wilderness areas around the world - as surely as a bulldozer or oil spill. But scientists have so little information about what landscapes should sound like without human interference that trying to correct the problem would be like a surgeon's wielding a scalpel without knowing the parts of the body, let alone his patient's symptoms. To restore ecosystems to acoustic health, researchers must determine, to the last raindrop, what compositions nature would play without us."

Yet even in Denali, "[a]n undeveloped swath of land nearly the size of Vermont," with only one, mostly unpaved, road entering the park itself, "scientists...have recorded only 36 complete days in which the sounds of an internal combustion engine of some sort were absent [since 2006]," reports Tingley.

While the profound and adverse effects of increasing noise levels on natural species have been noted in several studies, the effect on humans may be just as detrimental. "We're kind of severing the acoustic link that humans have with nature," laments Bryan Pijanowski, an ecologist at Purdue University.