Last year, 281.3 million people visited America’s national parks, down 4.2 million from a year earlier. With parks such as Glacier (above) likely to be glacier-less sometime around 2030, or sooner, authors Lauren B. Buckley and Madison S. Foushee (PDF here) track differences in attendance habits since 1979 to ask if climate change is affecting relatively mundane human activities such as park visitation:
Climate change has driven many organisms to shift their seasonal timing. Are humans also shifting their weather-related behaviors such as outdoor recreation? Here we show that peak attendance in U.S. national parks experiencing climate change has shifted 4 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 3 exhibit attendance shifts. Our analysis suggests that humans are among the organisms shifting behavior in response to climate change.
The authors are careful not to draw too much causal significance from a 4-day shift, but also place their study of humans in the context as the changing behavior of other animals:
The correlative nature of our evidence prevents attributing causation. Yet, our evidence complements that rapidly accumulating for other organisms showing behavioral shifts in the direction expected in response to climate change (Parmesan 2006).
This is consistent with the (thin) environmental economics literature:
Robert B. Richardson, John B. Loomis, "Adaptive recreation planning and climate change: a contingent visitation approach," Ecological Economics, 50(1-2):83-99, 2004., Pages 83-99
Abstract: This paper applies a contingent visitation analysis to estimate the effects of changes in climate and resource variables on nature-based recreation demand. A visitor survey at Rocky Mountain National Park included descriptions of hypothetical climate scenarios (depicting both weather- and resource-related variables), and questions about how respondents' visitation behavior would change contingent upon the scenarios. Survey responses are used to estimate the impact of climate change on park visitation and to test for the relative significance among climate scenarios and resource variables. A relatively small proportion of respondents indicated that their visitation behavior would change under the hypothetical climate scenarios, and the net effect on visitation is slightly positive. Both direct (weather-related) and indirect (resource-related) climate scenario variables are found to be statistically significant determinants of contingent expected changes in visitation. The results of the contingent visitation analysis are compared with the results of a regression analysis of historic visitation and climate variation for methodological assessment, and we find that they are in close agreement.
Here is another one (still unread).
