Fires. Droughts. Floods. Mudslides. Across the country, says the United States’s fourth National Climate Assessment, we’re experiencing these manifestations of climate change right now. And according to another landmark report, America’s national parks are warming at twice the national average.  

Analyzing data collected from 417 national park units going back to before the turn of the 20th century, the study, published in Environmental Research Letters, also found that rainfall in the collective national park area decreased by 12 percent compared to 3 percent across the rest of the United States. 

Why are national parks more vulnerable to temperature and weather changes than other lands? From the Alaskan tundra to the saguaro-studded southwestern deserts, national parks were set aside to protect and showcase areas of spectacular beauty, which often means they are in more vulnerable environments. “Human-caused climate change exposes national parks more severely because extensive park areas are in extreme environments,” says the report’s lead author, Patrick Gonzalez, a climate scientist at the University of California, Berkeley. “Much of the national park area is in the Arctic, at high mountain elevations, and in the arid southwestern U.S., and these are the parts of the U.S. most exposed to high temperatures or drought.”

Some of the changes threaten the very gifts the parks were set aside to protect. Joshua Tree National Park could lose its Joshua trees. Glacier, Grand Teton, and Glacier Bay National Parks could lose their glaciers. And Death Valley could more than live up to its name—by the report’s worst-case climatic calculations, America’s national parks could see temperature increases of 3 to 9 degrees Fahrenheit over the next 80 years.   

While the numbers are shocking in print, they don’t come as a surprise to someone who toured the national parks last summer and experienced the tragic consequences of climate change firsthand.

In Colorado’s Rocky Mountain National Park, lush stands of white pine and spruce that used to blanket whole mountainsides are now dead brown sticks, ravaged by bark beetles that have killed 834 million trees across the state.

Visitors to Zion National Park were barred for several months from climbing to famed Angels Landing and visiting the Emerald Pools, both damaged by flooding and erosion from an extreme early summer storm. 

And visitors to Yosemite–well, they couldn’t visit at all. For almost four weeks in July and August, Yosemite suffered an unprecedented closure as the Ferguson Fire raged just outside the park’s borders, shrouding it in dense, choking smoke. 

Wildfires aren’t a threat only in the West. Two years ago, a cluster of wildfires burned more than 10,000 acres of Great Smoky Mountains National Park over more than two weeks. Fueled by unusually low humidity after a prolonged drought and winds up to 80 miles an hour, the fire spread to surrounding communities, killing 14 people, injuring 150, and burning 2,400 buildings in the surrounding towns of Gatlinburg and Pigeon Forge. 

The danger to some parks is more insidious, noted primarily by biologists, botanists, entomologists, and other scientists studying park ecosystems. In Everglades National Park, for example, sea level rise is forcing mangroves to retreat inland and threatening rare tropical orchids with salinization. Sea level rise is likewise impacting Acadia National Park, where storm surges and high surf are changing the iconic shoreline and have flooded and damaged the park’s popular carriage roads.

Suffer the Creatures

Climate change is radically altering wildlife habitat; there is scarcely a mammal, bird, insect, reptile, or fish that isn’t affected in some way. Many species are heading to higher elevations in search of cooler temperatures or following plant and insect food sources that are themselves moving upslope. 

In worst-case scenarios, habitat is simply disappearing; polar bears are losing their sea ice, salmon lack cool streams to swim and spawn in, and snowshoe hares lose their life-saving camouflage when the snow melts too early.  

In Lassen National Park, the tiny, hamster-like rodents known as pika have followed the receding snowpack to higher elevations, only to find fewer of the talus meadows they need to survive.

The beloved wolves of Michigan’s Isle Royale National Park are dying out purely from isolation; Lake Superior no longer freezes solid enough most winters to form the ice bridges that once allowed the wolves to come and go from the mainland. Without this connection and the genetic diversity it supports, the pack was weakened by inbreeding and by 2017 was reduced to just two. This fall, four new wolves were introduced to the island in a last-ditch effort to save them; one died almost immediately.

Other problems come when food sources disappear or new pests appear, sometimes carrying diseases. Moose, for example, are being sickened and even killed by tick-borne illness, as milder winters allow tick populations to balloon. Bears in the Rocky Mountains that feed on the seeds of the now-disappearing white pines are seeking other food sources, including human trash.

Speaking for the Trees

In the past, cold winters that killed the eggs and larvae of North America’s 17 species of bark beetles kept them in check. Without those freezes, beetles breed and breed. Lack of precipitation, which weakens trees, also leaves them more open to infestation. 

The damage is most visible in the Rocky Mountains, where vast swaths of forest have gone from green to a dull, rusty brown. But few forests in the West are safe. In the Black Hills of South Dakota around Mount Rushmore National Monument, the dark-canopied ponderosa pines that gave the area its name are dying as well.  

In California, the National Park Service estimates that 129 million mountain trees have died over the past eight years, with beetles being a major factor. Meanwhile the state’s oak trees continue to die from the invasive pathogen known as sudden oak death, which has now spread to madrones, laurels, and even the state’s iconic redwoods. Even Sequoia National Park’s giant sequoias, considered one of the planet’s great survivors, are showing signs of stress from the prolonged drought. The widespread tree death is, of course, a factor in the incidence of horrific wildfires, which feed on the heavy fuel load. 

In Hawaii, a previously unknown strain of a beetle-borne fungus is decimating the native ohi’a trees that make up half of the state’s forests, including those in Volcanoes National Park. Known as ROD for rapid ohi’a death, it clogs and shuts down the tree’s vascular system, essentially strangling it. The disease, which probably arrived as a stowaway on a nursery import, has killed hundreds of thousands of trees, with mortality rates topping 90 percent in some areas.  Forestry experts believe it’s taking advantage of trees already weakened by climate change. 

Looking Forward, Not Back

Go to the web page for almost any national park today and you’ll find a section specifically devoted to climate change and its impacts on that park’s ecosystem. While plenty of the damage is here and now, some of the concerns remain threats—scenarios mapped out by scientists, rangers, and climatologists based on future estimates. That means we’re not there yet—and, in Gonzalez’s view, we don’t have to be. 

“Our results show that reducing carbon pollution from cars, power plants, and other human sources can save parks from the most extreme heat,” he says. “Compared to the highest emissions scenario, meeting the Paris Agreement goals would lower the rate of heating in the national parks by one-half to two-thirds by 2100.”

In other words, every step we take to reduce greenhouse emissions--from increasing use of public transit to energy conservation to renewable energy--will help save the U.S. national parks for future generations.