On July 2, the National Park Service released a report by two of its scientists that confirms that 289 of America’s parks and historic sites are experiencing climate change. That is, many are getting and staying hotter for longer, enduring more severe spikes in temperature, experiencing biblical deluges, or losing beach to erosion and rising tides. No great surprise, really, and the report is not alarmist but matter of fact: If future generations are to spend the Fourth of July visiting Jamestown, Va., say, or Harpers Ferry, W.Va., or floating on Lake Mead on the Nevada-Arizona border, steps will need to be taken — and soon — to better protect them.

“Studies like this are critical to inform national park managers and visitors alike about their local climate impacts so they can take proactive steps to address climate change,” says the nation’s top ranger, Jonathan Jarvis. The NPS director says the parks can be seen as an early-warning system and laboratory, too, because the parks are “places where we can monitor and document ecosystem change without many of the stressors that are found on other public lands.”

A few week ago, Jarvis’s boss, Interior Secretary Sally Jewell (the subject of a profile in last week’s Bloomberg Businessweek), convened a roundtable on climate impacts at Jamestown, the first permanent English colony in North America. She noted that Jamestown Island had already lost 98 feet of coastline, along with the remains of a Civil War fort and Native American artifacts estimated to be 10,000 years old. The climate science, she says, is clear, but even if you want to debate its causes, “all you have to do is open your eyes and look around you to see that it’s real. We have to deal with it.”

The former chief executive officer for Recreational Equipment Inc., Jewell points out that America’s parks aren’t just scenic landscapes and historical points of interest, but also economic drivers that contribute tens of millions of dollars to the U.S. economy annually — much of it to nearby communities. In 2012 (the most recent year for which figures are available), national parks across the country generated $26.75 billion in economic activity and supported 243,000 jobs. Those tourist dollars and jobs may decline if the parks fail to adapt.

Here’s a look at eight of the parks studied by scientists William Monahan and Nicholas Fisichelli in their report — and what’s at stake.

Ice caves at Apostle Islands National Lakeshore. Image: NPS

Apostle Islands National Lakeshore: The “jewels of Lake Superior” are a top draw for sailors and paddlers. In 2012, the park generated $24,030,600 in business, much of it in the vicinity, and supported 330 jobs.

Dunes at Cape Lookout National Seashore. Image: NPS

Cape Lookout National Seashore: This island at the southern end of North Carolina’s Outer Banks has a black-and-white argyle lighthouse and closed this Fourth of July because of Tropical Storm Arthur. 2012 economic activity: $20,883,900. Jobs: 297.

Chesapeake and Ohio Canal National Historical Park Image: NPS

Chesapeake & Ohio Canal National Historical Park: According to the new study, increased temperatures and hydrologic changes may affect access to and the structural integrity of bridges, locks, lock houses, culverts, dams and monuments here. 2012 economic activity: $81,886,200. Jobs: 1,117.

Barracks at Fort Larned Image: NPS

Fort Larned National Historic Site: Restored to its 1868 specs, this Kansas fort preserves a crucial base for protecting the Santa Fe Trail and provides a window on a violent period in the country’s westward expansion. 2012 economic activity: $1,852,800. Jobs: 24.

Mather Point on the South Rim of Grand Canyon National Park Image: NPS

Grand Canyon National Park: The epic walls remain unchanged, but future visitors may find less wildlife to admire as a persistent drought (13 years and counting) has dried the seeps and springs that slake a desert critter’s thirst. 2012 economic activity: $453,641,300. Jobs: 6,010.

Muddy Mountains Wilderness Area at Lake Mead National Recreation Area

Lake Mead National Recreation Area: The lake created by the Hoover Dam on the Colorado River has never been lower since it began forming in 1935. That’s not just a problem for houseboats. Las Vegas counts on Lake Mead for 90% of its water. 2012 economic activity: $252,209,900. Jobs: 2,840.

Sequoia National Park

Sequoia & Kings Canyon National Parks: The southern Sierra Nevada has seen its fire season extended and has been plagued by invasive species once killed by hard freezes. But the greater concern is the main attraction. Scientists warn that consistently high temperatures may lead to a die-off of the 3,500-year-old giant Sequoia trees. 2012 economic activity: $123,091,400. Jobs: 1,541.

This article originally published at Bloomberg here