The release last year of former Vice President Al Gore's award-winning film "An Inconvenient Truth" has turned global warming into a hot topic of concern in the United States.  One of the film's producers, Laurie David, has become a leading advocate for environmental issues.  David and singer-songwriter Sheryl Crow have just completed a two-week U.S. tour, raising the alarm about global warming with their music and their message.  VOA's Jim Bertel had a chance to sit down with the two activists to talk about their "Stop Global Warming College Tour."

Sheryl Crow and Laurie David during their concert tour stop in Washington, D.C.

In an interview with VOA, Sheryl Crow said the two environmental activists hatched the tour idea over lunch while discussing how they could make a difference.

Sheryl Crow

The 90-minute shows were a mix of Crow's music and David's environmental message.

"The environment is a beautiful spring day,” explains David. “It is a shady tree, it's the air you breathe and the water you drink.  And the environmentalism is the protection of those basic things.  That's the accurate definition.  And that makes us all environmentalists who still face the most urgent challenge of our lifetime -- global warming."

Scientists say carbon dioxide emissions from vehicles, factories and power plants cause global warming, and if efforts to curb this man-made environmental hazard do not increase soon, the results could be disastrous for the planet.

University of Maryland student Andrew Nazdin believes college students have an important role to play in saving the environment. "I see global warming as the threat to my generation.  It's the defining challenge of my generation.  If we don't step up and solve this climate crisis, my college degree, everything I worked for so far is not really going to be worth anything, because I am going to be living in such a dramatically altered world."

For many, the problem seems too big to make a personal difference.  But David says cutting carbon emissions starts at home, by using energy-efficient light bulbs and appliances.  She also says individuals can be the catalyst for change in government policy.

"People.  Government doesn't change until people demand it.  People have to demand it.  And that is one of the reasons we are out here trying to ignite this movement.  It is not going to happen until people demand it," says David.

The 11-city tour wrapped up on Earth Day (April 22) with a large show in Washington.  But the effort to bring about environmental change continues online, with a virtual march on Washington at stopglobalwarming.org.

"Instead of marching for just one day, let's march every single day until we are a million strong,” suggests David. “And we want to count every single person who says, 'I demand solutions now to global warming.'  And we started with one marcher, and now we're getting close to a million."

"And what everyone has to know is that this is not a political issue,” adds Crow. “This is a human-rights issue, and we have to demand change.  And the way change happens is for the movement to become so loud they can't block it out."

More than 700,000 people have enrolled in the "virtual march" so far.  Crow and David promise the campaign will continue until the number of marchers is great enough to make government leaders realize the time to address the global warming crisis is now.