While rising temperatures threaten to melt the glaciers in Glacier National Park and invasive African weed threaten to choke out the saguaros at Saguaro National Park, Bill Briggs points out in this MSNBC article that we’re still a big part of the problem.

The hundreds of millions of visitors to national parks, and their natural use as places to hike and drive are tearing the places down.

“Ultimately, I think one problem is that we expect the national parks to be static museum exhibits, when they are ever-changing dynamic landscapes subject to the same forces that the rest of the world experiences, from erosion to global warming to tectonic activity.”

Environmentalists suggest limiting vehicular traffic or at least limiting helicopter and small plane flights over sites like the Grand Canyon.