WASHINGTON — America’s national parks are warming up and drying out faster than other U.S. landscapes, threatening iconic ecosystems from the Everglades in Florida to Joshua Tree in California to Denali in Alaska.
That’s the conclusion of a new climate change study published Monday, the first to examine rainfall and temperatures in all 417 national parks sites. The study also forecasts the degree that parks could become hotter and more drought-stricken by century’s end, depending on whether nations undertake efforts to reduce greenhouse gas emissions, or continue with business as usual.
“U.S. national parks protect some of the most irreplaceable ecosystems in the world,” said the study, published in Environmental Research Letters, a peer-reviewed scientific journal. Reductions in industrial emissions could “substantially reduce the magnitude” of expected impacts, the study added, “offering hope for the future of the U.S. national parks.”
It is hardly news that climate change is challenging numerous national parks. In the Everglades, rising sea levels and saltwater intrusion threaten habitat and wildlife that depend upon fresh flows of water. Catastrophic wildfires threaten Yosemite and other national parks in California. In Montana, there is online debate about whether Glacier National Park should soon rename itself, or face accusations of false advertising.
Yet Monday’s study is the first to analyze how a warming climate affects the entire 85-million-acre national park system, a collection of particularly dynamic landscapes.
“A higher fraction of national parks are in extreme environments,” said Patrick Gonzalez, a forest ecologist at the University of California, Berkeley who authored the study with UC Berkeley colleagues and scientists at the University of Wisconsin, Madison.
National parks tend to be relatively high in elevation, where warming occurs more quickly because of the thinner atmosphere, Gonzalez said. In addition, a large proportion of park land is located in the desert Southwest and Alaska — regions feeling the strongest impacts of climate change.
The study found that, between 1885 and 2010, areas that are now national parks warmed by 1.8 degrees, twice the U.S. rate. It also found that annual precipitation in national parks declined 12 percent, compared to 3 percent drop in the United States overall, during that same period.
At current rates of greenhouse gas emissions, temperatures in the most exposed national parks — particularly in Alaska — could rise by as much as 16 degrees by 2100, according to the study.
With that level of increase, arctic permafrost could further melt, trees will replace tundra and wildfires will be more common and damaging. Many rare species would be unable to migrate to more comfortable climes, bringing some to the brink of extinction.
