Eagle Peak, the highest point in Yellowstone National Park, rests at 11,372 feet (3.466 kilometers). And Longs Peak in Rocky Mountain National Park scrapes the skies at 14,259 feet (4.346 kilometers). America's 417 national parks are often in extreme places, from Arctic tundra to alpine slopes to fragile desert treasures. And scientists say anthropogenic (human-caused) global warming is causing temperatures in these celebrated areas to increase at twice the rate of other parts of the country.
That's the conclusion of a study published in Environmental Research Letters, indicating that between 1895 and 2010, temperatures in the parks increased by a little over 1.8 degrees Fahrenheit (1 degree Celsius), double the U.S. rate of increase. In the same period, precipitation dropped about 12 percent, compared to about 3 percent around the rest of the country. The study was published on Sept. 24, 2018.
So why would that be? "National parks aren't a random sample — they are remarkable places and many happen to be in extreme environments," said Patrick Gonzalez, associate adjunct professor in the Department of Environmental Science, Policy and Management at UC Berkeley and a lead author for the study, in a press statement. "Many are in places that are inherently more exposed to human-caused climate change."
Higher temperatures mean drier forests throughout the West, along with increased length and severity in the wildfire season. Yellowstone's increasing warmth already means an extra month of snow-free terrain per year, along with higher average temperatures throughout the park. Glaciers and snowpack are melting faster than ever before. Droughts in the Southwest are extreme – and getting worse – as climate change accelerates, affecting not only parks but human health, too.
Alaska's national parks are exhibiting the greatest temperature increases, according to the study. But the trend is evident throughout the entire park system.
As the heat rises, entire ecosystems change. Above the tree line, plant and animal life adapted to colder temperatures suffer, while lifeforms that are better suited to warmth creep to higher elevations. Some creatures and plants, unable to tolerate the rapid climate changes, may disappear altogether.
These kinds of temperature shifts have happened before in Earth's past, but typically spread over thousands of years. Because of human greenhouse gas emissions from vehicles, factories and the like, those climate shifts are now taking place in just decades.
For years, scientists have been spreading the word about heaping piles of evidence regarding climate change, and the national parks are akin to canaries in the coal mine. If we continue to blast our emissions into the environment, temperatures at parks could skyrocket by more than 16 degrees F (9 degrees C) by 2100. Even if stricter regulations are enacted, the researchers expect that more than half of the park system will see an increase of 3.6 degrees F (2 degrees C) before the century's end.