Climate Change Trends, Impacts, and Ecosystem Carbon Across U.S. National Parks

New spatial analyses of climate show increasing temperatures in US national parks while a new synthesis of field research finds widespread physical and ecological changes detected and attributed to human climate change. If the world does not reduce greenhouse gas emissions, continued heating could increase the vulnerability of plants, wildlife, physical features, and cultural resources in the 409 US national parks to substantial changes or damage. Field research also shows that US national parks protect ecosystems with the highest carbon densities in the world, the conservation of which naturally reduces the magnitude of future climate change. From 1895 to 2010, the average annual temperature of the US National Park System increased at a statistically significant rate of 0.9 ± 0.2 degrees Celsius per century, three times higher than the US as a whole. Twenty-six published research efforts that used data from national parks detected changes attributed to human climate change. The historical impacts include glaciers melting in Glacier National Park, corals bleaching in Virgin Islands National Park, biomes shifting in Yosemite National Park, trees dying in Sequoia National Park, and sea level rising in Golden Gate National Recreation Area. Eighty-one published analyses found future vulnerabilities of national park resources to continued climate change. These include increased wildfire in Yellowstone National Park, flooding of sections of Everglades National Park and the National Capital Parks in Washington, DC, shifting vegetation in Gates of the Arctic National Park and Preserve, and loss of marmot habitat in Mount Rainier National Park. National parks help prevent future climate change by protecting carbon in vegetation. Redwood National Park and the other parks in California contain an amount of carbon equivalent to the annual emissions by 7 ± 3 million Americans. Much of our knowledge about global climate change comes from published research conducted in U.S. national parks. The historical impacts and future vulnerabilities to climate change highlight the importance of reducing emissions from power plants, cars, and other human sources to protect the globally unique US national parks.