7 Climate Threats to U.S. National Parks

How the country’s most iconic landscapes are in danger

Debbie R. King
8 min readSep 2, 2023
The Grand Canyon. Photo by NWimagesbySabrinaEickhoff on Pixabay.

“How about this crazy weather we’re having?” A good conversation starter but not so favorable for humans, non-humans, and the planet. It seems that every other week, some part of the country is experiencing epic storms, flooding, off-the-charts heat, intense hurricanes, and wildfire smoke blanketing the east coast — the last, unheard of to this native Virginian.

But most terrifying was waking up to the news of wildfires spreading across Maui where two friends had landed to attend a family wedding right before the deadly wildfires broke out. They enjoyed classic Hawaiian cuisine at Kimo’s in Lahaina and then spent an isolated couple of days at their hotel without power and an internet connection, subsisting on peanut butter, cereal … and rumors of what was happening a few miles away.

Dinner and drinks at Kimo’s in Lahaina. Two days later, the restaurant was gone. Photo by Kevin Black.

I can’t help feeling this summer that someone has taken a match to the earth and fanned the flames.

Why national parks?

Naturalist John Muir’s vision of an untouched, pristine landscape maintained in its original condition led to the creation of the National Park Service (NPS) in 1916, which protects and preserves over 85 million acres of the country’s most scenic and cherished landscapes and ecologies in all fifty states.

Many national parks are located in extreme and elevated environments, arctic regions, deserts, or coastal areas, where they are susceptible to erosion, landslides, flooding, drought, insect infestation, wildfires, and more.

A 2018 UC Berkeley and University of Wisconsin-Madison study conducted on 417 national parks concluded on average that the parks have heated up by slightly over one degree over the past century, twice the rate as the rest of the country. Over that same period (1895 to 2010) yearly rainfall on average decreased by 12 percent throughout national parks, nine percent more than the rest of US land. Parks in Alaska have experienced the most dramatic temperature escalations, while the largest drop in rainfall has occurred at Hawaii’s Volcanoes National Park.

Patrick Gonzalez, associate adjunct professor in the Department of Environmental Science at UC Berkeley and first author of the study stresses how climate change is changing the parks.

“Human-caused climate change is already increasing the area burned by wildfires across the western U.S., melting glaciers in Glacier Bay National Park and shifting vegetation to higher elevations in Yosemite National Park.”

In 2021, a National Park Service (NPS) vulnerability assessment revealed that almost 75 percent of national parks are at risk for cumulative effects of climate change while more than half are at risk from high-impact events such as wildfires or sea-level rise.

Here are a few of the most visible impacts of warming temperatures on the U.S. national parks.

1. Glacier melts and thinning

Today, 95% of Alaska’s 100,000 glaciers are thinning or retreating, including at Glacier Bay National Park where glacial ice has decreased by eleven percent since the 1950s. Three glaciers in Mt. Rainier National Park were downgraded in June 2023.

In Glacier National Park in Montana, all 26 glaciers (originally down from 100 in 1910 when the park was founded) decreased in size over fifty years, some by as much as 80 percent. The US Geological Survey indicates that all the glaciers in the park will disappear by the end of the century.

As conditions become hotter and dryer, the availability of cold fresh water for the state and farmers, and for generating hydroelectricity will decrease as the glaciers continue to melt. Wildlife will suffer as well.

2. Flooding

In June 2022, muddy swirling waters stormed through the northern section of Yellowstone National Park, sweeping away roads, bridges, and campsites and sending 10,000 park visitors home. The unexpected combination of warming temperatures and a dense atmospheric river led to intense rain and river crest hikes not seen in 100 years.

“Human-caused climate change is already increasing the area burned by wildfires across the western U.S., melting glaciers in Glacier Bay National Park and shifting vegetation to higher elevations in Yosemite National Park.”

3. Permafrost thaw

National Geographic reports that 75 percent of the permafrost underlying Denali National Park dropped to 50 percent in 2000, destabilizing the scenic road that winds around the park, releasing stored greenhouse gases, changing the hydrology and ecology of the landscape, and altering habitats and vegetation. The remaining permafrost layer is expected to decrease to six percent by 2050.

4. Sea-level rise

But it is not just western mountainous regions suffering the impacts of elevated global temperatures. Floridian sea-level rise is threatening one of the most unique wetlands in the world, the Everglades, home to a diversity of exotic species such as the American crocodile, Florida panther, and West Indian manatee, as well as numerous endangered wading birds.

The park’s broad ecosystem of mangroves separates freshwater and the ocean for now, but as rising seas, flooding, and hurricanes continue to batter the coast there is concern that the mangrove barrier could break down, pushing native wildlife into salt-water areas they cannot survive.

Purple gallinule tropical marsh bird is found from Orlando south to the Everglades. Photo by Abhardphoto on Pixabay.

5. Drop in rainfall/drought

Hawai’i Volcanoes National Park on the Island of Hawai’i spans seven ecological systems, making it one of the most diverse landscapes in the world. The park, which surrounds two active volcanoes — Kīlauea and Mauna Loa — tops Global Citizen’s list of parks most impacted by climate change due to the precipitous drop in rainfall over the last century, creating dryer, hotter conditions, increased risk of wildfires, and pushing endemic species toward extinction.

The Colorado River runs through the Grand Canyon, splitting the renowned park into two red-, purple-, and orange-striped layers of sedimentary rock that rise to dizzy heights. But the impact of climate change stunts the river’s flow, altering the park’s ecosystem, species habitats, and hydrology, and increasing the risk of flooding, rock slides, wildfires, and storms.

6. Decrease in diversity/endangered species

Hawaiian Honeycreepers, a highly diverse and adaptive group of birds are endemic to the island with some only existing in Hawai’i Volcanoes National Park. These colorful birds with adaptive bills are dwindling, with only 17 species remaining (down from 50 to 60) and four on the endangered list. Warming temperatures are threatening honeycreepers’ high-elevation habitats that protect them from avian-malaria-carrying mosquitos.

The ʻiʻiwi honeycreeper is under threat of becoming endangered. Photo by NPS.

Small mammals, birds, and plants are on the move in many of the parks, heading north toward cooler elevations. One small mammal struggling to hold onto its alpine habitat is the American Pika, a small mammal of the rabbit family, that inspires “awwws” and inhabits higher elevations in some of the national parks.

Cloaked in a heavy fur coat and insulated by high metabolism to survive cold temperatures, pikas live exclusively in alpine regions of national parks and puff themselves up into a ball to keep warm. As temperatures warm, pikas are in danger of losing their habitats and becoming extinct; pikas can overheat and die in temperatures as low as 78 degrees.

Photo by Derek Ryder on Unsplash.

7. Wildfires

No climate-fueled threat seems to be escalating faster than wildfires. A U.S. Forest Service study verifies that climate-fueled fires are burning hotter, longer, and are more frequent. Fire seasons are lasting longer than in the late 1970s due to high temperatures, high winds, and decreased rainfall. Longer fire seasons mean more carbon dioxide is released into the atmosphere.

During widespread fires in 2021, iconic giant sequoias in Sequoia National Park got special blankets to protect their bark and prevent embers from entering through old fire scars. Fire crews wrapped the bases of giant ancient sequoia trees, some of which have been growing for several thousand years, with aluminum-based fire-retardent blankets. The largest tree in the world, General Sherman, with a massive base 36 feet in diameter, received a protective blanket as well as others, that helped survive the raging fires.

But a few years ago, the NPS reported that six fires burned more than 85 percent of the giant sequoia grove spanning the larger Sierra Nevadas in only six years, in contrast to only 25% of groves charred over the previous 100 years.

“I can’t help feeling this summer that someone has taken a match to the earth and fanned the flames.”

Yosemite — a study in climate change impacts

The National Park Service portrays the parks as living laboratories where scientific study can help better understand the impacts of climate change. Yosemite National Park with its dramatic granite formations of El Capitan and Half Dome, is a prime example of how many national parks are suffering the impacts of climate change.

Yosemite Falls at Yosemite National Park. Photo by Sheng L on Unsplash.

In the past few years, rampant wildfires forced the park to close. In 2013, the Rim fire scorched 250,000 acres of the park, becoming the third-largest fire in California’s history.

Garrett Dickman, a forest ecologist with the National Park Service, comments to CNN on the upward climb of trees and vegetation in the park as temperatures continue to rise.

“People come to Yosemite because we have some of the biggest trees on Earth. But the whole experience in Yosemite is starting to be altered … We’re just kind of seeing that tree line lift up in a weird way.”

Climate harbingers

While many questions surrounding the deadly Maui fires remain unanswered, one glaring truth stands out—that of invasive grass and shrub species that moved in once sugar cane and pineapple production shut down in the 1990s, leaving an incendiary landscape ripe for fanning by Hurricane Dora’s winds. Yet, the signs were missed.

Similarly, National Parks are climate harbingers, bells clanging loudly to teach us valuable lessons in outdoor classrooms as global temperatures continue to rise.

“National parks aren’t a random sample — they are remarkable places and many happen to be in extreme environments,” Patrick Gonzalez emphasizes. “Many are in places that are inherently more exposed to human-caused climate change.”

The question is, will we listen?

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If you visit a national park …

  • Leave no trace: Do not litter; dispose of waste properly or take it with you. Do not leave waste in campfires. Leave rocks, shells, and plants as you find them. Adhere to campfire warnings.
  • Respect wildlife: No selfies with the buffalo. Don’t feed the bears (or other wildlife). Stay on established trails to avoid harming habitats.
  • Protect and preserve: Visit parks at off-times or seasons. Let nature sounds prevail — no loud voices or yelling. Donate to park protection.



Debbie R. King

Sharing insights on sustainable living and how human narratives impact the planet.