Interior Secretary Sally Jewell has an Earth Day message for the United States, "make a major course correction on environmental issues." In a speech at the National Geographic Society in Washington, Jewell decried the $12 billion maintenance backlog at national parks and called for passage of the National Parks Centennial Act to better fund the repairs.
The Senate on Wednesday passed legislation to permanently reauthorize the Land and Water Conservation Fund, something Jewell wants the House to do as well, saying America is at the dawn of a new conservation era.
"Americans are more determined than ever to solve the problems we face," she says. "To take action to confront climate change, to pass ballot initiatives to fund parks and open space, to work the lands in a sustainable way, to give everyone an equal chance to get outdoors."
According to Vickie Carson with Mammoth Cave National Park, a $5.5 million project to rehab the cave's historic route began last year. She says it was the single biggest construction project in the National Park Service in 2015.
Helen Siewers, executive director of the Friends of Mammoth Cave National Park, says the park has a very active research program to better understand and protect the resources there.
"There's a fabulous amount of collaborative research going on with universities in the area to bring students to the park," Siewers says. "To see things they won't see anywhere else and research things they can't pursue anywhere else."
Jewell says a new study by the National Park Service underscores the value of the parks.
"Parks generated $32 billion in economic activity for the nation in 2015," says Jewell. "They did that on a budget of about $3 billion - meaning that for every dollar invested in the national parks, taxpayers saw a 10-to-one return on investment."
In honor of Earth Day, National Park Week and the 100th anniversary this year of the National Park System all national parks are free this weekend.