America's National Parks Most In Peril From Global Warming

America's national parks are being adversely affected by climate change, with temperatures becoming more extreme in recent years compared to the historical norms of the last century, a new study by the National Park Service (NPS) finds. 

"These changes will have implications for what visitors see and experience in national parks and will require new approaches to the protection of natural and historic resources within parks," the NPS says. America's national parks attract 275 million visitors a year. The NPS celebrates its centenary the year after next.[slideshow:1017]

NPS Director Jonathan B. Jarvis calls climate change "the most far-reaching and consequential challenge ever faced by [America's] national parks." In Grand Canyon National Park, for example, warmer temperatures and extended drought are reducing sources of drinking water for all wildlife and posing a direct threat to endangered species.

Related: National Parks Ranked

The effects of climate change vary around the country. National parks in Hawaii and the desert southwest are getting hotter and drier. Parks in the northeast are getting warmer and wetter. Parks in the Midwest are getting warmer, but precipitation patterns are not much changed. Parks in the southeast are showing signs of the effects of the "warming hole," a large area over the region where temperatures have cooled not risen because of high levels of acid-rain-causing sulfates in the air.

The study identifies six national parks — Acadia, Big Bend, Carlsbad Caverns, Guadalupe Mountains, Joshua Tree and Saguaro — four national seashores — Assateague Island, Cape Cod, Fire Island and Padre Island — and three national preserves — Big Thicket, Jean Lafitte and Mojave — where average mean temperatures have already reached the upper end of those experienced in any year since 1901.

The adaptation by flora and fauna to these changes is equally complex with many parks likely to experience temperature and precipitation regimes unlike any they have seen in more than a century. The different responses of species to these new conditions are likely to cause "natural communities to disassemble and novel communities to form," the study says. 

The study is not the first to warn of the threat climate change poses to America's national parks, and it reiterates previous recommendations that in order to protect park resources for future generations, national parks will have to be managed beyond their administrative boundaries. This will require difficult management decisions requiring input from the public and other stakeholders, likely pitting the public interest of the national parks against the rights of private property. For example, the report says, Point Reyes, the only national seashore on the Pacific coast, may need to create new protected shoreline and wetlands on neighboring land rather than build seawalls to protect those it already has.

See also: Economic Value of National Parks