It was a wind of good fortune that blew American writer-director Jeffrey Nachmanoff into Roland Emmerich's path for special effects extravaganza The Day After Tomorrow. The two hit it off so well they're now collaborating on a political satire, One Nation, which looks set to create as much media interest as their ecological disaster pic, now out on DVD...

Do you feel The Day After Tomorrow has changed people's awareness of global warming?

The movie was made, obviously, to entertain people. It's a Hollywood movie, so you don't make a movie to convince people one way or the other about an issue. But we stirred the nest. It didn't bother me that there were people running around saying, "The movie's all fiction," because that brought a lot of other people out of the woodwork who went on TV and radio and said, "Actually, this much is true." I know very well what is real and what is fake, but the public have no idea - they just see this big special effects movie. The beauty of it is, it gave them the opportunity to hear from a lot of scientists about the issue. Hopefully that gave people a little more insight into the problem.

You say you know what's real and what's fake in the movie. So what should people really be worried about?

OK, here's the way I lay it out to people. Are we about to be thrust into an Ice Age in a matter of weeks? No. Is the Statue of Liberty going to turn into a giant popsicle overnight? No. But basically, is it possible for human activity to create enough greenhouse gases that can fundamentally alter our climate system? The answer, the scientists think, is yes. That is a very possible and significant risk.

Now the one that we discuss in the film is the idea - discussed by Dennis Quaid - that polar melting could disrupt the North Atlantic current and trigger a cooling in the Northern Hemisphere. That is a possibility - not a likely one, but a possibility. Scientists say there's a less than five percent chance of it happening. I thought, Oh, that's not so bad, but then one of the scientists said to me, "Jeffrey, would you get on a plane if I told you it had a less than five percent chance of crashing?" Of course not, so that's the way you have to think about it. Our movie was made about the spectacular problems, but the more day to day problems - which really don't make for very good movies - are probably the ones that people should be paying more attention to, and I'm happy if our film can get people to think about the problem at all.

How did the scriptwriting process work with Roland Emmerich? Did he write the special effects sequences and you concentrate on the characters?

It was a little more subtle than that. Certainly, in general Roland came up with more of the special effects ideas, and I came up with the character ideas. But there was a healthy back-and-forth. There were times when each one of us would exert an influence on the other's, shall we say, area of expertise. I remember having long arguments and discussions with Roland about how the LA tornado sequence would work. And he would often have very strong opinions on 'the kids', and it was very healthy.

I think the best films have collaboration and mutual respect between the filmmakers. It's one of the things I admire about the British film industry. Some of my favourite filmmakers are British - Stephen Frears is one of my favourite directors, Mike Newell as well... They tend to work very closely and collaboratively with their writers - there's a very healthy collaborative spirit here. I think the auteur theory probably hurts sometimes because you give a director - I don't want to bash any of the American directors - but there are some that come out of music videos, or this and that, and they don't necessarily know story that well. But everybody tells them that they are the king, and everybody tells them that they are the auteur, and they actually start to believe it. Instead of taking advice from their collaborators, they start to ignore it and the films suffer. Everyone wonders why they make bad Hollywood films sometimes, and they make it not because there aren't loads of talented people - there are loads of talented people running around the set and on the production. The problem is they're not always getting heard. And then you end up with a movie that is much weaker than it should have been. I guess I'm trying to give credit where it's due: I feel Roland was very good at collaborating.

You've got another project coming up with Roland called One Nation. What's that about?

It's another project that allows us to dabble our toes into the political field, because it's about corruption in American politics, and how a president ends up turning against an establishment. It's a near-Civil War situation. We can have a lot of fun with it, and even maybe make a few satiricial political points. We're about halfway through the first draft of the script right now.

Do you have any movie frames of reference?

It's a little bit of a weird one, because it has elements of a big serious political movie like All The President's Men, and then it has more satirical moments - like a movie such as Network, which I always loved. Then there are some elements of the action genre too - a little more of a conspiracy movie, like Three Days Of The Condor or Enemy Of The State. We've got a couple of different things in the mix.

It's interesting that you mention three great 70s movies there...

That's probably because those are references for me. It's very hard to get movies like that made now - you can't go as dark as you could in the 70s, but I look to the great movies and I try to take inspiration from them. For Roland, the biggest inspiration for Day After Tomorrow was The Poseidon Adventure, which was another 70s movie. American movies were great in the 70s, I don't know what happened.

Special effects?

Yeah, maybe. I think we have to go back to what was working properly then and now also use the special effects, because you can't ignore them.

You spent some time growing up in London. Would you like to work here?

I'm trying. I would love to make a movie here. In fact, when I eventually write and direct a movie, I would love to do it in London. I think it's such a great place for character-driven films, and you have so many great actors here. The stakes are different - it's hard to get the money together for a film set in London, but if you can do it, you can make the movie for a lot less. Americans have almost forgotten how to make a movie for less than $10 million, but it's clearly an artform that is very healthy and alive here.

Do you have a timescale in your head for when you'd make the movie here?

In the next three years would be good. I have to try and cement my work a little bit more on the larger scale movies in Hollywood, but hopefully I'll be able to do that with another movie or two, and then be in a position to do something a little smaller and more personal.

Any actors in mind?

Actors I would love to use? There are so many British actors I love, I wouldn't limit myself. By the way, one of my favourite things about Tomorrow is the fact that Ian Holm was in a movie I wrote - that was a big kick for me. And the fact that it ended up being a disaster movie is just hysterical!