They highlight a range of threats and challenges faced by the trail from encroaching development to invasive species. The report reminds me why I first became interested in issues surrounding coal power plants when I lived near the Great Smoky Mountains.
Increased concentrations of ground-level ozone are a concern along the Appalachian Trail. Ground-level ozone is formed by chemical reactions that occur when nitrogen oxides and volatile organic compounds combine in the presence of sunlight. The risks of elevated levels of ozone to humans include lung tissue damage, reduced lung function, and increased lung sensitivity to other irritants. High concentrations of ozone also affect a plant’s ability to produce and store food, which compromises growth, reproduction, and overall plant health. These weakened plants are then more susceptible to disease, pests, and environmental stresses. Air pollution, including ground-level ozone and acidic precipitation, is substantial across much of the Appalachian Trail corridor and is increasingly contributing to the death of sensitive vegetation, including red spruce (Picea rubens) and sugar maple (Acer saccharum).
(Goofy pose at Clingman's Dome along the AT)
Problems associated with invasive species are repeatedly mentioned. That's another impact of climate change as species move into new areas.
It's an excellent report but they could have done a better job of identifying the sources of problems related to air pollution and climate change that are having a major impact on the trail.