Imagine Shenandoah National Park without its autumnal showcase of colors, or a sign along the Virginia coastline noting that the site of the Jamestown colony is offshore and under water. Both scenarios could be realized in less than a century if human-influenced climate change isn't slowed, according to a report.

Compiled by the Rocky Mountain Climate Organization and the Natural Resources Defense Fund, the report envisions Shenandoah without the many hardwood trees that provide the kaleidoscope of Fall color, and Jamestown Island as well as the Chincoteague National Wildlife Refuse inundated as a result of sea-level rise.

The report does, though, qualify its conclusions, saying it's difficult to make local predictions related to climate change compared to large-scale predictions. "These should be taken as suggestions of future change, not definitive predictions," the authors point out. "... future temperatures may be either lower or higher than projected using the scenarios used in this analysis. With effective global actions to reduce heat-trapping gases, future temperature increases can be held lower. On the other hand, emissions in recent years have gone up faster than assumed in even the highest-emissions scenario developed by the Intergovernmental Panel on Climate Change..."

That said, the report stated that not only would the predicted impacts be damaging in their effect on natural, cultural, and historic resources, but overall they'd have a significant adverse effect on Virginia's economy due to reduced tourism, the report's authors said.

"Drawn by their natural and historic wonders, nearly six million people a year visit (these sites), adding over $200 million in spending to Virginia's economy and supporting over 4,000 jobs," reads the executive summary. "But these contributions to Virginia’s economy are threatened by how climate disruption puts at risk the natural and cultural resources that draw visitors to these special places."

The Jamestown scenario doesn't seem entirely that far-fetched when you realize that a 2003 hurricane, Isabel, "flooded 90 percent of the site's one million artifacts, forcing the National Park Service to relocate the entire collection to another facility for restoration," the report notes.

Stronger hurricanes, as some believe will occur as climate change takes greater hold of the planet, could contribute to erosional problems along the Virginia coastline that would impact resources at the Yorktown battlefield, part of Colonial National Historical Park, adds the report. "One key site at risk is Redoubt 10, on the edge of a cliff along a stretch of the York River that has suffered erosion over the years," the report states. "This was the scene of a key battle won by Revolutionary forces under the command of Colonel Alexander Hamilton, part of the decisive final offense that led to the surrender a few days later of the British army at Yorktown, effectively ending the Revolutionary War. The nearby Moore House, at which the terms of surrender were arranged, is also potentially exposed to shoreline erosion.

In Shenandoah, a warming climate could lead to an infusion of pines at the expense of its oak and hickory forests.

"The park's signature resource is its forests, which cover 93 percent of the park and are among the nation's greatest biological riches. When the forests are ablaze with the colors of fall, they are a magnet to many; park visitation is always at its peak in the weeks that leaf color reaches its peak," reads the report.

Stephen Saunders, president of the climate group, said these examples, along with a prediction that Chincoteague National Wildlife Refuge would face a "wholesale transformation" from sea-level rise, demonstrate why "human-caused climate disruption is considered the greatest threat ever to our national parks and wildlife refuges."

"These ... special places deserve particular attention. They show how much Virginia has at stake, from its coasts to its mountains and from its natural and cultural resources to its economy, as people alter the climate," Mr. Saunders said. "And these ... special places are extraordinarily important not just to Virginians but also to Americans everywhere.”

According to the report, even lower greenhouse gas emissions in the future would lead to problems in these areas. At Jamestown, temperatures could rise anywhere between 1.7 degrees Fahrenheit and 5.8 degrees Fahrenheit by the end of the century, while a high-emission scenario would likely see temperatures rise between 2.6 degrees and 9.3 degrees. At Shenandoah the range of higher temperatures would be between 1.7 degrees and 6.7 degrees under the low-emission model, and 2.6 degrees and 10.8 degrees under the high-emission model.