Some might believe the world needs another environmental documentary like it needs a hole in its ozone layer. An Inconvenient Truth, as acclaimed and popular as it was, seems to have done more to service the celebrity of Al Gore and Melissa Etheridge than to trigger a groundswell of eco-change.

So, the existence of a Johnny-come-lately like The 11th Hour, which boasts the imprimatur of Leonardo DiCaprio as co-producer and narrator, can be partly chalked up to limousine liberalism and profit margins more than CO2 levels.

However, it is the absence of sustained indignation that justifies yet another movie on perhaps the defining issue of our generation. Without a constant drumbeat, a parade gets out of step or, even worse, stops marching altogether. It is the reason McDonald’s is quietly phasing back in its supersized menu itemsunder different labelsthree years after ostensibly abolishing them in the wake of Morgan Spurlock’s Super Size Me.

Superficially, The 11th Hour is a stuffy syllabus, relying on a roundtable of academic, scientific, political and philosophical talking heads for its heft, with Leo appearing periodically to remind us that we are still sitting in a theater watching a movie. But if the message of An Inconvenient Truth was delivered by an ex-vice president trying to rewrite his legacy and perhaps rekindle a political career, it is the learned, diverse opinions offered by the likes of Stephen Hawking, James Woolsey, environmental activist David Suzuki, Nobel Prize winner Wangari Maathai, Duke University professor Stuart Pimm, and many others that give this film its backbone of credibility.

The film’s greatest distinction and strength is that it is not exclusively a screed against global warming and impending eco-disaster (although that is certainly its crux). The 11th Hour adopts a more holistic viewpoint by focusing on the larger context of humankind in Earth’s chronological history. The sobering truth is that while many refer to an “environmental crisis,” the term is a misnomer: It is not the environment that is in peril, but rather our ability to survive in it. When Suzuki informs that 99.9999 percent of all life that has ever inhabited Earth is now extinct, it reminds us of our tenuous position in the planet’s life cycle.

Marshaled by first-time directors and sisters Nadia Conners and Leila Conners Peterson, the experts posit that humans’ ability to conceive and comprehend nature led to our ascent to the upper rungs of the animal kingdom. Conversely, our disconnect from nature, beginning with the technological advances that accompanied the Industrial Revolution, has led to a slow decline. Yet, The 11th Hour offsets its doom-and-gloom with solutions to at least some of our environmental woes, and it is here that our capacity for ingenuity may hold answers if accompanied by sufficient resolve. Woolsey points out that over three and one-half years beginning in 1942, a mobilized and motivated United States went from converting its entire industrial infrastructure for war production to vanquishing the Axis powers across Europe, Africa and Asia. (It is an observation that further questions the methodsand motivesbehind our now four and one-half year Iraq folly.)

The film’s most provocative and precarious underpinning is its designation of corporatism and economic globalization as mankind’s ultimate evil. We have become purveyors of and slaves to rank consumerism, losing not only our commune with nature but also our natural resources. Still, as astute this sentiment might be, it is an ironic one coming from a Hollywood-made vessel, for which you have to plunk down eight bucks and probably sit through a dozen or more advertisements in order to see. Truly altruistic producers might have paid theaters to show the doc for free or run it on network television without commercials or distributed complimentary DVDs. That may sound Pollyannaish, but otherwise The 11th Hour and its star wattage threaten to get lumped into the same morass of economic opportunism it decries.

Now, if you’ll excuse me, George Clooney is on television telling me which brand of beer I need to buy. Good night, and good luck, indeed.

The 11th Hour opens Friday in select theaters.