Don’t where nylon in the desert as it melts on to you. That was the sort of thing I was taught in school geography lessons. It was the end of imperial geography and our lessons focused on the sort of things you might need to know if you were being sent out to run West Africa. It was old-fashioned but it didn’t put me off.

At university Stan Openshaw taught us how to blow up a nuclear power station in a lecture. He filmed himself approaching it with a cardboard bazooka, to show us which building you would knock out first. As a student, it was one lesson I never forgot. It would be completely illegal nowadays but he did it as part of a series of lectures about nuclear power and safety. It was his idea that I do a PhD in visualisation because he’d heard that visualisation was becoming the latest thing in computing.

I started producing the maps in The Atlas of the Real World because a normal atlas is completely wrong [within the context of human geography]. It only shows you a tiny proportion of the population and what they do. If you draw anything on a normal map of Britain you’re not drawing the black people because they only live in tiny dots in the city. Instead, what you’re largely looking at is rural areas where nobody lives.

One of the ways we could reduce wealth inequalities in Britain is by introducing a land value tax. If it was £0.07 per year per square metre times the value of your land, most people would hardly pay any, less than £7 a year but wealthy landowners, including the queen, would pay a lot more. And £0.07 per square metre for ten years would wipe out the national debt completely.

There’s a big difference between the perception of immigration and multiculturalism in the UK and the actual facts. For a start, people think that half the people in Britain are black whereas it’s actually about eight or seven per cent. Only one in ten people in Britain are born overseas and the most concentrated group of people born overseas and now living in London are Americans. In central London one in seven children around Hyde Park were born in the US. That’s your biggest ghetto of overseas immigrants but we don’t think of them as immigrants. And, it all balances out, because just as one in ten people living here were born overseas, one in ten of Britons are living overseas. But we don’t think of ourselves as immigrants, we think of ourselves as ex-pats.

When immigrants come to Britain they tend to do remarkably well. Within a very short time, children of immigrants are doing better than the British population. It's nothing to do with genetics or race, it's simply because, like most people who move abroad to improve their prospects, their parents have a huge amount of get up and go. The same is true for the British people who move overseas too.

Swelling populations are not causing the current environmental crisis. Of the new babies born in the world, 97 out of every 100 are born in the poorest countries in the world. Their effect on pollution is tiny. The biggest increase in pollution has been in countries where population is declining. Essentially there’s an inverse correlation between population and pollution over time. It’s the richest people in the world who are causing the most pollution by flying and other forms of consumption.

The UN’s projection for world population is that we stop at around nine billion in forty years time. That means, for the first time since the black death or when we went to the Americas with our diseases, the world population is going to fall. We’ve actually controlled our fertility. Most of the world is below fertility replacement now. The world’s population is going to stop at nine billion and go down. It’s an enormous achievement. And it’s largely an achievement of women, and particularly poor women who have been able to get hold of contraceptives or say, 'No'. Literacy is the best predictor of this. As soon as you see tiny improvements in female literacy, women gain more control of their own lives and you see dramatic falls in fertility.