So climate change doesn't exist, huh? Your vacation plans might say otherwise.
Lauren Buckley, an assistant professor of biology at the University of North Carolina, thinks a lot about climate change and how different species—grasshoppers and butterflies, in particular—are changing their behavior as the planet warms up. It can be a disheartening business. “I’m racking up one more example for a butterfly species, when the public is debating whether climate change is a real thing,” Buckley says. But one day it occurred to her that instead of studying insects, her research group might look a different species.
It turned out that nobody had ever researched humans' adaptations to climate change, so this November Buckley published a study of peak attendance at national parks since 1979. Her research showed that human beings may be reacting to changes in climate without even realizing it. Out of nine parks that showed a shift in mean spring temperatures, seven also showed a shift in the timing of peak attendance (including the Grand Canyon). Out of 18 parks that did not show a temperature shift, only three showed an change in attendance. In other words, when parks got warmer earlier, people started showing up earlier, too.
Responses to climate change are harder to pin down in humans than in other species. Flowers blossom, birds migrate, and butterflies emerge from their cocoons and take wing on a regular schedule. Climate researchers are already seeing shifts that track with climate change models in these types of animal behaviors. Humans, though, have more agency in their actions. “It's incredibly hard to track why people are making these decisions at a given time,” Buckley says.
It’s also hard to find data that documents humans’ seasonal behaviors. Buckley looked at data sets on ice cream and hot dog consumption, on sales of snow shovels, and on attendance at zoos and aquariums. The data about national parks stood out because it would allow her to compare two different sets of parks—parks that had temperature change and ones that didn't. With data like that, Buckley says, “When you step back and look at the big picture, you can see that subconscious change... Even though many people are still debating climate change, their human behaviors are actual responding to it.”
Not everyone agrees that techniques designed to analyze animals’ behavior can be applied to humans: social scientists, in particular, question whether human data can be treated the same way as data from other organisms. But Buckley found that her results matched well with behavioral patterns that scientists are seeing elsewhere. One piece of evidence doesn’t prove that climate change is altering the way humans live life, but more researchers are likely to start probing into the question. “It's hard to attribute any one particular response to climate change,” Buckley says. “But when you have many responses to climate change, you have that linkage.”