After a solid opening in four theaters in New York and Los Angeles last weekend, the environmental documentary The 11th Hour is scheduled to expand Friday into nine additional U.S. cities and most major cities in Canada. Warner Bros. said earlier this week that it plans to roll it out into some 250 theaters in the coming weeks. The film, narrated by Leonardo Dicaprio, is being closely watched to see whether the actor can pull more young people into theaters than former Vice President Al Gore did with his similarly themed documentary An Inconvenient Truth last year. In an interview appearing in today's (Thursday) Chicago Tribune, DiCaprio credited Gore's movie with bringing the problem of global warming "to the consciousness of the American public in a way that can't even be comparable to three years ago." Separately, he told today's Boston Herald that he doesn't regard himself as an expert on the environmental issues explored in his film. "I wanted to take the position of a concerned citizen of the world," he said. However, DiCaprio's celebrity may have become a flash point for some critics. John Harkness, writing in Toronto's alternative weekly Now Magazine, remarks that the actor's narration "is not bad -- in a 'My Science Project' way" and that the film itself "preaches to the converted." Mark Jenkins in the Washington City Paper writes that DiCaprio "comes across like a washed-up '90s child star who's now paying the bills by doing infomercials: 'You can save the Earth for only $9.99 a month!'" And James Verniere, writing in the Waltham, MA Daily News Tribune, comments that, compared to Gore, DiCaprio "seems more like an idealistic whelp with a nasal voice and a wispy goatee." But Sam Adams in the Philadelphia City Paper comes to the opposite conclusion, writing that while Gore's film is "a much better movie," DiCaprio's is "far more important." Adams's judgment: "The ideas it puts forth are both more frightening and more energizing than those in Al Gore's carefully weighted polemic."