 Singer Sheryl Crow began a bus tour of US colleges to raise awareness about global warming on Monday, one of several high-profile celebrities to take up the cause of climate change. Crow, a Grammy award winning singer/songwriter, will speak about the issue and sing at the college stops. "I am here because the more I learn about global warming the more I feel compelled to do something in my own way whatever that is," she told reporters at Southern Methodist University in Dallas as the tour began. Accompanied by global warming activist Laurie David, Crow is traveling in a biodiesel-powered bus to university campuses with a final stop in Washington for Earth Day on April 22. Texas was chosen as the starting point because it leads all US states in fossil fuel emissions, with its heavy industry and love affair with big pick-up trucks. Other celebrities such as Leonardo DiCaprio, Robert Redford and Daryl Hannah have joined the campaign to reduce fossil fuel emissions and curb climate change. Former Vice President Al Gore has helped make the issue fashionable with his Oscar-winning documentary 'An Inconvenient Truth,' which David produced.