The world "is on a precipice" as it struggles to deal with the three "tremendously frightening crises" of climate change, poverty and war, says Brian Mclaren, one of the foremost leaders of the emerging church movement.

"This is our home and it's fragile and it's beautiful but it's also really in danger," he says in a new short film for Hope08.

He then turns his attention to the "crisis of poverty" and the "huge gap" between the rich and the poor.

"It's an unsustainable system when you have a gap like that."

The third crisis, he warns, is the worldwide proliferation of dangerous weapons.

"You take those three crises and you put them together and it tells us that we have to wake up, we can't just go on with business as usual."

Yet the popular and sometimes controversial author and speaker still sees cause for hope.

"A friend of mine says there are really only two tribes in this world: there are the haves and the have-nots," he says. "The hope that we are looking for in the world involves both of them. It involves the have-nots not giving up and it involves the haves learning to care."

The short clip was commissioned by the Christian Enquiry Agency and Church Army and launched today to coincide with the seventh anniversary of September 11 on Thursday.

In the film, Mclaren shares his personal story of reaching out to his Muslim neighbours in the days following the terrorist attack by sending a letter and making visits to local mosques to reassure them of his support.

"It took this to make me come and want to introduce myself," he says.

Gareth Squire, Director of the Christian Enquiry Agency, believes McLaren is an example of how the Christian faith can impact the world.

"Brian's wider work is very timely, and reminds us that genuine inward personal transformation inevitably leads to transformed decisions and actions, a profound concern for all people everywhere, and a commitment to being part of the solutions the world needs, not its problems.

"I'm glad we could make a film that recognises that Christian faith is a real hope for the present, just as much as it is a solid hope for the future."

Hope Explored is the fourth phase of Hope08, a yearlong church initiative to demonstrate faith in action and restore hope in communities across the UK. As part of Hope Explored, churches will spend the autumn inviting people to deepen their understanding of Christianity by taking part in courses explaining the faith.

On the web: www.hopeinfo.co.uk