By 2100, visitors walking the grounds of California’s Joshua Tree National Park may view exhibits showing what will have been lost — the spiky yucca palms that inspired the park’s name, dwindled to a few rare husks.
Climate change could kill most of the park’s iconic trees, wildfires may transform the towering conifer forests at Yellowstone National Park into scarred grasslands, and once-mighty ice sheets in the north will probably melt and flow into the sea, making Glacier National Park both an obsolete name and a hard lesson about environmental degradation.
A new study published Monday has warned that climate change has adversely and uniquely affected many of the 417 national parks spread across the United States and its territories, according to scientists from the University of California at Berkeley and University of Wisconsin.
“Human-caused climate change exposes the U.S. national parks to severely hotter and drier conditions than the U.S. as a whole,” Patrick Gonzalez, a climate scientist at Berkeley and a lead author of the study, told The Washington Post on Tuesday.
The consequences are alarming, the study suggests. Some of the most sacred and ecologically sensitive areas in the country, from the Grand Canyon to Yosemite and Denali, may decay into ghosts of their former mighty selves and be unrecognizable to future generations expecting to inherit a planet hotter than they received.
Researchers looked at data between 1895 and 2010 and concluded temperatures in national parks increased twice as much compared with other parts of the country, while precipitation fell dramatically at those parks.
That is because parks are often in places sensitive to shifts in climate. Many parks are at high elevation, where the Earth warms quickly due to a thinner atmosphere, researchers said. Alaska is severely affected because melting snow uncovers darker surfaces that absorb heat.
Alaska is also where 63 percent of all national park area is located, the study says.
In the Southwest, rising temperatures coupled with droughts have ravaged the region, where many other parks are found.
It is vital to defend national parks, which make up 4 percent of U.S. land, researchers said, because the protective measures mean national parks are becoming even more important sanctuaries for plants and animals. And the parks hold vast amounts of watersheds to replenish drinking water, along with trees to soak up carbon.
Two centuries of burning fossil fuels have produced twice as much carbon that can be absorbed by forests and oceans, and excess carbon in the atmosphere has reflected sunlight back to the Earth, Gonzalez said. It is a natural process, but human activity has helped add carbon dioxide to the atmosphere at levels not seen for 800,000 years, he said.
Reducing greenhouse gas emissions is the best way to reduce climate impact at the parks, the researchers said.
The National Park Service said it relies on studies, such as the newest one, to inform policy, in which climate change is one factor among others in its decision-making.
"It is our job to understand and know how to manage effects from a changing climate so that we may protect park resources, just as we manage the impacts of invasive species or erosion or wildfire,” said Jeremy Barnum, an agency spokesman, in a statement Tuesday.
The agency said the study describes natural events that take place “outside the climate change conversation,” such as wildfires caused by humans.
But the effects of climate change on national parks are clear and documented, the researchers said.
Jack Williams, a climate researcher at the University of Wisconsin, told The Post Glacier National Park in Montana, which draws admirers for its snowy peaks and mirror-like lakes, may lose its namesake because of rising temperatures and glaciers already in retreat.
“It’s very likely under the highest rates [of warming] that the glaciers would melt,” he said.
Further north, in Alaska’s Glacier Bay, the once enormous Muir Glacier has melted hundreds of meters from the 1950s to 2010.
At Yellowstone, drought and wildfires have thinned towering forests, and scientific projections point to fires that burn more frequently. It could turn the region into rolling grasslands, Williams said.
Wildfires are naturally occurring and typically ideal for forests to clear underbrush, researchers said, but arid conditions and federal policies to stamp out fires has translated to drier and denser kindling that make fires more intense.
Gonzalez, who is also the principal climate scientist for the National Park Service but spoke about his research in his capacity at Berkeley, said Yellowstone faces another threat connected to human activity.
The winter cold used to kill bark beetles. But warmer seasons have extended the life of these insects, which can feast on trees longer and in greater numbers. The transforming ecosystem there may also force the iconic bison and other animals away from familiar grounds, researchers said.
The researchers pointed to some solutions already underway.
Gonzalez said the agency has made efforts to identify particularly vulnerable areas in parks, along with a focus to protect areas where life may be able to take shelter and thrive in good local conditions. The parks have also focused on reducing emissions, he said.
Some parks have been proactive, Williams said. In Maine’s Acadia National Park, for instance, biologists have introduced limited numbers of trees from further south that may be better suited to a climate that will probably grow warmer in coming decades.
At Assateague Island National Seashore in Maryland and Virginia, a new visitor’s center was built onshore out of concerns about storms, erosion and rising sea levels, the agency said.
Williams said the parks will almost certainly be different in a century than they are today, but how different will depend on decisions to either reduce emissions or allow them to escalate.
But the parks will exist, in some form.
“Glacier National Park may be without glaciers,” he said, “but it will still be a beautiful park.”