War, famine, pestilence and death: backed by human greed and ignorance, the four horsemen of the apocalypse are currently joint-favourites in the environmental armageddon stakes.

The ice-caps are melting, the population is booming, forests are disappearing, we can't drink the water, our children can’t breathe, and it doesn’t matter who we vote for because Big Petroleum rules the world.

We’ve reached what scientists call ‘the tipping point’. Unless we stop pumping crud into the biosphere, plundering the planet’s natural resources, and turning it into one giant farm right now, we – like the thousands of lesser life-forms we consign to the history books each year - are heading for extinction.

So thank the acid-laden heavens that big-name eco-warriors like Al Gore and Leonardo DiCaprio are willing to use their clout for the greater good.

After the crusading senator’s inconveniently truthful (and apparently truth-stretching), feature-length PowerPoint presentation, comes this rallying cry from DiCaprio’s awareness-raising foundation.

Leo doubles up as producer and narrator, popping up to reinforce the opinions and exhortations of the great minds on show from Darwinists, creationists and spiritualists to capitalists, politicians and pioneers of sustainable design.

How seriously you take views on globalisation from a bloke called Jerry Mander or Gloria Flora’s lowdown on deforestation remains to be seen, but the facts are inescapable.

Annually, the US spends more on war than Australia spends on everything. There are now twice as many people on Earth as when Kennedy was President. And as Stephen Hawking points out: land is finite; there is no more.

Oscar-winning editor Pietro Scalia (JFK, Black Hawk Down) is on hand to balance the talk with scenes of humankind’s nature-screwing activities and their calamitous consequences.

The eco-conscious won’t learn much new and some of the explanatory graphics are too hurried to be easily absorbed, but it all adds up to a lucid and dynamic round-up of the current ecological situation.

Yet while The 11th Hour deserves a wide audience, you get the feeling that Leo is preaching to the converted.

It's a sad state of affairs when society will only heed a warning against the perils of consumerism if it comes with a celebrity endorsement.

Let’s hope the irony can be converted into understanding.

Elliott Noble