Humans are creatures of comfort, so perhaps it should not be a surprise that warming temperatures associated with climate change are altering the seasons slightly when it comes to visiting national parks, according to a study.
Lauren Buckley, a biology professor at the University of North Carolina at Chapel Hill, made that discovery when she and an undergraduate assistant analyzed visitation data from the National Park System.
“I usually work on other species’ responses to climate change, like grassphoopers and butterflies, and actually we do do some work in the national parks, in Rocky Mountian National Park, for that," Professor Buckley said the other day. "But we do spend a lot of time trying to find pretty sparse data, so it occurred to us there’s all this human data out there and we were wondering whether we could see similar responses in human data, and there hadn’t been much research on it.
“So we gave it a try, and I think we found some pretty interesting results.”
According to their calculations, "peak attendance in U.S. national parks experiencing climate change has shifted (on average) four days earlier since 1979. Of the nine parks experiencing significant increases in mean spring temperatures, seven also exhibit shifts in the timing of peak attendance. Of the 18 parks without significant temperature changes, only three exhibit attendance shifts."
Granted, a four-day shift over 32 years isn't earth-shattering, but it does reflect that human visitors to the parks have comfort zones and, like animals, birds, and plants, are changing their habits in response to climate change.
“At this point it’s probably not that big of a deal in terms of park planning and such, but it is a statistically fairly strong relationship and sort of proof of concept that human behavior does actually appear to be shifting in response to climate change," Professor Buckley says. "That rate of change is fairly similar to that that we see for other organisms, so that’s about what we would have expected if the human behavior is tracing the advancement of spring weather."
In compiling the research, the professor only considered parks that have had annual visitation of more than 100,000 during the entire three-decade period she analyzed, and excluded parks with user limits, such as Mammoth Cave National Park, where there are limits on the number of people who can join any one tour.
At some southwest parks, the peak attendance date shifted more than four days. For example, at Grand Canyon National Park it shifted from July 4 to in 1979 to June 24 in 2008, and at Mesa Verde National Park it has moved from July 10 to July 1.
In redrock parks such as Bryce Canyon, Zion, and Capitol Reef national parks in Utah, increasing attendance in the fall months -- which are seeing longer periods of nice weather -- initially moved the peak attendance date later into summer, the professor found, although it later reversed course towards earlier in the summer.
While one conclusion that can be reached is that humans are looking to avoid the hottest days of summer when visiting national parks, Professor Buckley added that, "I would also think more so what we see for a lot of organisms is just sort of the earlier arrival of spring. So we did see the shift in a lot of alpine parks and my sense would be that if the snow is melting earlier, the flowers start coming out earlier, there’s more pleasant weather to come to the parks earlier."
Interestingly, the human movements in response to the warmer temperatures mirror those of species.
"The consistency of our response across parks is similar to that observed across species," the two wrote. "Of the nine parks that have experienced significant temperature increases since 1979, 78% exhibit shifts in the timing of peak attendance; 71% of species exhibited a phenological shift."
The paper was published in the International Journal of Biometeorology.