Climate seems pervasive in how it will affect human life on Earth — from ocean acidification to allergies. Scientists know a lot about how diseases may shift their range and how some species may adapt, but understanding how many tourists may visit the Grand Canyon each year in a warmer world hasn't exactly been on a high priority.

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Perhaps it should be. Many parks are already seeing the physical effects of climate change in action, and tourism can have a huge impact on local economies and how protected areas are managed. Now, a new analysis published June 17 aims to predict how climate change will affect travel to some key tourist destinations in the United States: National Parks.

To see how people respond to temperature changes in different parks, a team of researchers from the National Park Service looked at how temperature fluctuation compared to visitor fluctuation at 340 parks across the United States from 1979 to 2013. For the most part, visitor numbers increased with temperature — until things got too hot to handle. When temperatures hit 77 degrees Fahrenheit tourism started to drop.

The team also projected how tourism might fluctuate from 2041 to 2060 under two different predictions for how climate change might alter average air temperature. Their results highlighted some key trends. High latitude, high elevation parks showed a general increase in tourism with temperature, one that was more pronounced in Spring and Fall. Parks with historically warm temperatures were more likely to experience a drop in tourist flow as it got even hotter, especially during warmer months.

Though the results might not seem super surprising — when it's really hot, people don't want to spend time outside — they still can help park managers understand their expectations for visitor levels and maintenance. Gregor Schuurman, one of the study co-authors and an ecologist on the NPS Climate Change Response program, told Laura Santhanam of PBS News Hour:

You may not be able to achieve your [attendance] goals the way you could in the old days with a changing climate. If you’re going to have a productive visitors season, you can’t ignore a melting glacier or flooding access road.

A few parks a have plans in place to cope with climate change's effects on tourism in their region. For example, when Hurricane Sandy hit Assateague National Seashore in Maryland, the storm swept away parking spots in some areas and buried others in sand, Santhanam writes. Given that extreme weather events are expected to increase, the park has made some changes since Sandy. They've started using crushed clamshells for parking spaces and plan to begin using a new mobile infrastructure system in the fall.

Hopefully, the new report will encourage other parks to come up with strategies of their own.