Population growth is a massive climate change issue. There, I’ve said it.

Our species has grown too successful (in terms of population) for its habitat. We do not have enough natural resources for people to live sustainably in the coming decades. Most people do not live sustainably now – if we are not burning fossil fuels in the West, we are sucking our groundwater dry or eating the last bluefin tunafish. In the developing world, the remaining rainforests are being chopped or burned, again with the groundwater, and so on. Too many people.

This past week, Jairam Ramesh, India’s environment minister complained that American diplomats were trying to get the population issue into Copenhagen’s negotiations. He said: “Influential American thinktanks are asking why should we reward profligate reproductive behaviour? Why should we reward India which is adding 14 million people every year?”

Good, and about time. If we are serious about dealing with climate change then we need to discuss how the world is to deal with all the issues, including population.

But, let’s not forget that while India, China and Bangladesh continue with their destructive swell, things aren’t looking that rosy closer to home. The US population, a substantial 306 million, is projected to grow by 46% by 2050, according to its national census bureau – the global average is 38%.

Climate predictions for the States are pretty scary: dustbowl scenarios worse than in The Grapes of Wrath, water shortages, increased hurricane intensity… Couple that with the enormous socioeconomic inequalities already prevalent in the country, and climate change will have a terrible impact on millions of people there.

So, let’s talk about population: if it’s not a homegrown increase in your country, then it’ll sure as hell become an immigration increase as the world warms and our species’ habitat becomes scarcer.