07/07/2016 12:42 BST | Updated 08/07/2017 06:12 BST

Only When Everyone Gets Behind Sustainability Will We See Change Really Happen

David M. Benett via Getty Images

I'm not a crier. I don't cry in real life. Yet when I'm watching a good film, I can be easily turned into a blubbering mess. And I'm not alone. I have friends who couldn't bring themselves to see my first major movie, War Horse, because they didn't want watch horses in pain - even after I'd explained that, on set, the horses were treated better than the actors. Films are just films, after all.... Or are they?

Since the release of the film Blood Diamond, the percentage of conflict diamonds on the market has been said to have dropped from 15% to as little as 1%. In 1993, Philadelphia, a movie about homophobia and the AIDS crisis, became the twelfth highest grossing film in the US. It made homosexuality and HIV/AIDS subjects that people no longer needed to be afraid of talking about. Just six weeks after the 2004 release of Supersize Me, McDonalds changed its portion sizes worldwide.

Films can change our perceptions, the way we live and think. They move us. They make us laugh, cry and empathize. A film really can change the world.

The film industry, and Hollywood in particular, have a reputation for shallowness and vanity and yet, it gives me goose bumps when I see a film with a true moral conscience.

I love film, as you can probably tell by now, and have been incredibly lucky to have been able to work as an actor in the film industry. One of the other privileges of working in film is the opportunity to work with charities. This is something I've been very selective about. Nothing makes me cringe more than watching an actor talk about a cause from a script, something their agent has maybe set up, that even with the best of intentions from everyone involved, fails to come across as genuine. It's hard to say no to good causes but I looked hard find the ones I was genuinely passionate about. This is where I discovered an organization called tve, standing for Television for the Environment.

tve shares my passion. It understands the impact that film can have. It makes and delivers films on global issues to viewers around the world. What's wonderful is, that because it uses the medium of film, its messages aren't constrained by social, geographical or economic boundaries. Their films are viewed by everyone, from the heads of huge global organizations to kids growing up in the most disadvantaged parts of the world.

On November 28 this year, tve will host its annual tve Global Sustainability Film Awards. Companies around the globe enter films of up to 10 minutes in length on their innovations in sustainability and the environment. This year's categories reflect the global goals for sustainable development agreed by world leaders in 2015. These goals set ambitious targets for world development, including eradicating poverty and hunger; ensuring good health, quality education for all and gender equality; and setting targets for affordable and clean energy, climate action and responsible consumption and production.

Here's where the power of film comes in. For an idea to really take hold and change to happen, it's not enough for the head of a company to meet new environmental requirements. It's not enough for an individual to start recycling or buying food from a sustainable source. We need everyone. Whether they're a factory worker in Delhi or the CEO of a global conglomerate on Wall Street, if we're to make sustainability real, we need them. Only when everyone gets behind an idea can change really happen. And one way of getting them behind that idea is film.

How can film, over all other art forms, be so evocative and span such a wide demographic? Well, I believe it's because film encompasses nearly every art form: visual, music, spoken word, photography and physical movement. Bono once said, 'A song can change the world.' Just imagine what a film can do.