National parks more affected by rising temperatures than rest of country, Zion most impacted in Southwest

Images courtesy of the National Park Service, St. George News

ST. GEORGE— National parks and other protected lands are being affected by climate change more than the rest of the U.S., a recent study reveals.

The study, performed by a team led by University of California, Berkeley climate change scientist and associate adjunct professor Patrick Gonzalez, used spatial analysis and GIS to analyze climate data and temperature for all 50 states – and every national park individually – from 1895 to 2010. According to the study, the data reveal that national parks have been more affected by rising temperatures than other geographical areas.

“Up until our research, the severity of climate change across all the U.S. National Parks was unknown,” Gonzalez said.

The research found that compared to the U.S. as a whole, which has warmed about 0.4 degrees Celsius, or 0.72 degrees Fahrenheit since 1895, national parks have warmed about 1 C, or 1.8 F, on average.

The area that has been most affected is Denali National Park in Alaska, which has warmed by 1.6 C per century, while the least affected protected land area is the Tuskegee Airmen National Historic Site in Alabama.

A map showing the change in temperature over the past since 1895 | Image courtesy of Patrick Gonzalez, St. George News | Click to enlarge

The Southeast has been the least affected by climate change in general, having warmed very little due to things like air pollution and increased rainfall which helps compensate for the warming, Gonzalez said.

The opposite is true in the Southwest region of the U.S., where national parks and other protected lands have experienced relatively higher rates of warming.

Zion National Park has seen the most significant increase in temperatures among Southern Utah parks, increasing by 1 C, almost 2 F, since 1895.

Bryce Canyon National Park has seen an increase of 0.6 C, Cedar Breaks National Monument 0.8 C and Arches National Park 0.5 C.

Grand Canyon National Park has warmed, but the change has not been significant, increasing in temperature by only 0.3 C, according to the study. 

One degree per century doesn’t seem like much, Gonzalez said, but the effects are equivalent to pushing a mountain down in elevation by 500 feet. Plants and animals that are used to a certain average temperature are being affected by even these slight increases, he says. 

“Small increments of temperature can translate into big changes on the ground,” Gonzalez said.

The National Park Service has also looked at the rise in global temperature over the years by analyzing data in each park over periods of 10, 20 and 30 years and determining how many times a park experienced “extreme” warm and cold temperatures as well as extreme dry and extreme wet seasons. NPS considers conditions “extreme” if they exceed 95% of the historical range of conditions.

A graph showing historical temperature changes from 1895 to 2010 | Image courtesy of Patrick Gonzalez, St. George News | Click to enlarge

They found that Zion experienced five instances of “extreme warm” weather, but no other extreme variables. Bryce Canyon experienced six “extreme warm” seasons, while Arches had two “extreme warm” variables and one “extreme wet” variable. The Grand Canyon had five “extreme warm” variables between 1901 and 2012.

The reason why protected lands are more affected by increasing global temperatures, according to Gonzalez, has to do with their locations, such as arctic areas and the arid Southwest.

“We’ve conserved the most remarkable places in the country and they often happen to be in extreme environments,” Gonzalez said.

Not only do changes in temperature affect the parks, but the amount of rainfall makes a difference as well. The most significant decrease in rainfall has been reported in Southern California, particularly in Joshua Tree National Park, though Lake Mead on the Nevada and Arizona border has also seen significant decreases. Southern Utah parks have seen a small increase in precipitation, Gonzalez said, but despite the added rainfall, the interaction between precipitation and temperature is considered more important.

“The hotter temperatures have outpaced the rainfall so that it has become more arid in many places because you may get a little more rainfall but it heats up more so you get more evaporation and so it gets hotter,” he said.

A graph showing Zion National Park temperature trends over the years | Image courtesy of the National Park Service, St. George News | Click to enlarge

NPS predicts that rising average temperatures will increase park visitation, particularly in Zion. In a 2015 study on how climate change will increase park tourism, researchers looked at the historical relationship between monthly average air temperatures and visitation data. They then predicted future visitation based on climate change projections and estimate that Zion’s annual visitation will increase between 8% and 26% by 2041.

Part of the University of California, Berkeley team’s research, however, was projecting future changes in temperature using the assumption that current warming trends will continue. 

According to their projections, there may be an increase in the frequency of wildfires in the Southwest, particularly in the Grand Canyon.

In addition to more frequent wildfires, warming is expected to affect wildlife habitats. One example of this is the pika, a small mammal related to the rabbit family, which was, until recently, commonly found in Zion and Cedar Breaks. But in 2015, scientists from the United States Geological Survey were unable to locate them in the area. Pikas are considered an indicator species, and current thinking suggests their reduction in population may be the result of climate change affecting their habitat, according to the USGS.

Additionally, these hotter and drier climate conditions cause droughts, which reduces the availability of drinking water for wildlife and has the potential to dry out soil and damage crops, according to the United States Environmental Protection Agency. Drier climates can reduce a tree’s ability to defend itself from pests like bark beetles, which can kill trees, and also infested around 50,000 acres of Utah forests in 2012.

Email: mshoup@stgnews.com

Twitter: @STGnews | @MikaylaShoup

Copyright St. George News, SaintGeorgeUtah.com LLC, 2019, all rights reserved.

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