Climate Change Amplifies Wildfires in National Parks

Yosemite National Park
Photo Credit: Rakshith Hatwar

Scientific Frontline: Extended "At a Glance" Summary: Climate Change and Upslope Wildfire Expansion in National Parks

The Core Concept: Human-caused climate change is severely escalating wildfire frequencies above natural levels in major California national parks by driving vegetation biomes into higher elevations.

Key Distinction/Mechanism: While fire managers historically relied on pre-European settlement baselines (specifically 1849) to plan controlled burns, this new approach utilizes forward-looking climate modeling. It predicts how warming will shift lower-elevation vegetation upslope, introducing high fire risks into alpine areas where wildfires were previously rare.

Origin/History: Since 1895, temperatures in Yosemite, Sequoia, Kings Canyon, and Lassen Volcanic National Parks have increased faster than the global average, demonstrating that historical 1849 reference conditions are no longer sufficient for managing modern forest health.

Major Frameworks/Components:

• Vegetation Biome Shifts: Climate modeling indicates that biomes could shift 230 to 480 meters upslope under maximum emissions scenarios, placing red fir forests and alpine grasslands at acute risk.
• Emissions Scenarios: Under the highest greenhouse gas emissions trajectory, regional fire frequency could double or triple by the end of the century (2071–2100). Conversely, rapid emissions reductions could stabilize fire frequencies near current levels.
• Predictive Risk Assessment: A new analytical framework replaces historical fire data with projected climate reference conditions to target understory fuel reduction.

Branch of Science: Climatology, Forest Ecology, and Environmental Science.

Future Application: National Park Service personnel will utilize these park-specific datasets to make proactive field decisions, such as where to allow natural ignitions to burn and where to implement low-severity prescribed fires to safely clear understory fuels.

Why It Matters: Wildfires are necessary for forest health, but the artificial climate-driven acceleration threatens to destroy critical mountain ecosystems. Ultimately, cutting carbon pollution remains the fundamental requirement for mitigating catastrophic fire risks in protected landscapes.

Fire frequency in Yosemite National Park. Left: Estimated 1849. Middle: Actual fire from 1950 to 2023. Right: Projected 2071–2100.
Image Credit: Gonzalez and Verkerke, 2026, in Environmental Research Letters.

New UC Berkeley–led research indicates that continued climate change could severely increase wildfires above natural levels in Yosemite, Sequoia, Kings Canyon, and Lassen Volcanic National Parks. The study, which was published today in Environmental Research Letters, also provides data for park managers to reduce risks by proactively targeting natural fires to decrease understory fuels.

“Fire is natural and necessary for forest health in California, but human-caused climate change is increasing wildfires above natural levels,” said lead author Patrick Gonzalez, an associate adjunct professor in the Department of Environmental Science, Policy, and Management. “Through this work, I aim to help National Park Service staff, who have previously told me of the need for park-specific data to inform field decisions on fire management that account for climate change.”

Fire managers currently use pre–European American settlement in 1849 as a reference condition to select areas for letting naturally ignited fires burn or for low-severity prescribed burning to reduce understory fuels. However, the researchers found that since 1895, climate change has already increased temperatures in the four national parks more than the global average.

To project further changes in wildfires, Gonzalez (PhD ’97, Energy and Resources) and his coauthor, Joshua Verkerke (MS ’24, Environmental Science, Policy, and Management), analyzed how climate change could cause vegetation biome shifts in Sierra Nevada mountain ecosystems. “We found that the conventional method missed areas at risk under climate change,” said Gonzalez.

The research found that climate change could shift biomes 230 to 480 meters upslope under the highest emissions scenario, with red fir forests and alpine grasslands at the highest risk. Upslope shifts of lower-elevation vegetation could expand fires into areas where wildfires are currently rare. Furthermore, the study found that under the highest emissions scenario, continued climate change could double or triple fire frequency. Fire frequency could stay the same or just slightly increase under a reduced-emissions scenario.

“Our results provide data for a new, forward-looking approach of using climate change reference conditions to set goals for ecosystem conditions,” said Gonzalez. “Ultimately, cutting the carbon pollution from cars, coal burning, livestock, and other human sources that cause climate change remains the fundamental solution to reduce fire risks and protect our national parks.”

Additional information: Gonzalez previously served as principal climate change scientist of the US National Park Service and assistant director for climate and biodiversity of the White House Office of Science and Technology Policy.

Published in journal: Environmental Research Letters

Title: Climate change increases risks of wildfire and biome shifts in United States national parks in California

Authors: Patrick Gonzalez, and Joshua Verkerke

Source/Credit: University of California, Berkeley

Edited by: Scientific Frontline

Reference Number: as072926_01

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