19/11/2015 12:44 GMT | Updated 19/11/2016 05:12 GMT

We Must Act Now Before Life on Earth Becomes Unsustainable

Imagine if an asteroid was hurtling towards the planet. If we knew when it would hit, and what the consequences would be, would we demand action? Would we allow our governments to quibble over who, exactly, was responsible for implementing an asteroid defence system? Or would we demand immediate global action?

When it comes to sheer urgency, that's the position we are in right now. A combination of climate change, biodiversity loss, population explosion and over consumption could lead to a point in the not-too-distant future when the Earth is unable to sustain the lives of the 10 billion people the UN predicts by the 2060s. Imagine for a minute what living in this world might be like.

For some years I had been reading with growing concern about the impact we humans are having on the very ecosystems that make it possible to sustain life. I had long been pondering how to make a film about this, frustrated that the films that were being made rarely managed to do more than preach to the converted. When producers Nick Kent and Mark Bentley gave me a copy of Ten Billion by Stephen Emmott it presented the perfect opportunity to make a film that took a cold hard look at the predicament we are in, and at what our future might be like if we fail to act.

Emmott's thesis, originally presented as a theatrical lecture at the Royal Court and then in book form, is not designed to make the reader feel better. It is a jarring, urgent wake up call. As Stephen says, we are facing "an unprecedented planetary emergency".

Reading Stephen's book was like a bolt out of the blue. It was not that that it contained much information that was new to me, but rather the way he told the story, linking together such apparently disparate issues as deforestation and agriculture, population growth, mass extinction and the fossil fuel industry. It reaches a terrifying conclusion that changed my way of looking at the world. It was like reading a horror story, though one based on rigorous scientific principles. I found it completely compelling.

Put simply, we are the victims of our own ingenuity. Rapid industrialisation, increased birth and survival rates, and the "green revolution" in food production mean that there are more humans than ever before: in turn this drives more consumption, more need, more demand for resources such as coal and oil that are ultimately damaging to the ecosystems we depend on for our own survival.

In clear, simple language Stephen shows the way that climate change, the extinction crisis, resource depletion, water management, food production and energy production are dragging the whole edifice of our modern consumer society to the precipice of disaster.

The clarity of his thinking and the terrifying acuity of his vision of the future convinced me that his polemic Ten Billion should be brought to the screen, to help disseminate these ideas so that they might stimulate debate, discussion and maybe even action.

For me the film is not so much about the overpopulation the title Ten Billion suggests, as it is about the over-consumption of the entitled. All of us who live in the developed world lead prosperous lifestyles of a luxury and extravagance unknown to all but the very elite of past generations. We feel entitled to this wealth and luxury, and are unwilling to accept that unfettered economic growth might in itself be problematic. In this we are ill served by our politicians who have to pander to the short timescales of the electoral cycle rather than grapple with the issues that will haunt us in decades to come.

Stephen's arguments are prescient. In Ten Billion, he warns of a situation where prosperous countries begin to fortify themselves against migrants escaping from hunger, poverty and conflict over resources: few who saw the barriers go up at the eastern limits of the European Union this year could deny this is now looking like a reality.

I had initially been concerned as to how a film could most effectively illustrate the emerging and alarming trends discussed in Ten Billion. Yet each of the negative impacts predicted are already managing to make themselves felt. I understood after months in the cutting room looking at film archive material that as William Gibson wrote "The future is here, it's just not evenly distributed yet. Looking at the archive footage it was apparent that the future is already upon us, and it is a fearsome place.

The nations of the world meet in Paris at the end of November to discuss climate and sustainability at the COP21 conference. It will be a pointless talking shop if representatives do not approach those talks armed with the insights put forward in Ten Billion and the ever-growing store of facts and research that urge action in the work of many of our planet's brightest minds.

If the world has seemed an ever-more unstable and unsafe place in the past few years, the real worry is that we haven't seen the half of it yet. It's time to face up to the future, before we destroy it.

Ten Billion screens at Curzon Soho, London on 25 November 2015