If we want to stop the climate emergency, we need to break the taboo around population and contraception

It's become extremely tricky to discuss the environmental effects of the world's growing population. But with emissions and habitat destruction both on the rise, the birth rate is going to have to come down

“So you didn't want to get pregnant, but you decided not to use contraception?” It’s difficult not to sound patronising during these kinds of consultations. I've tried out different versions of this phrase a number of times but never quite pulled it off. Sometimes I reverse it: “You didn't use contraception but also you don't want to be pregnant?”

This time my patient takes the hit. I see a shake of the head and a wry grimace. We move on to the morning-after pill, but then I force a return to the contraception discussion. I want the patient to have a plan for the very next time they have sex. I don't ever want someone pregnant unless they choose to be pregnant.

I am lucky enough to be supported in this by the country I live in. Every school child in the UK is informed about contraception, and both men and women are engaged in the conversation. Contraception use in the UK among women of 15-49 is 89 per cent, high even compared to the European average of 69.2 per cent. Every GP practice, every family planning clinic offers contraception advice, and every prescribed contraceptive is completely free.

Consequently, the fertility rate has dropped to 1.7 babies per woman – a figure to be celebrated.

But across the world, human populations are increasing rapidly. The data is there for everyone to look at. Some countries’ populations have tripled in a generation. The average fertility rate across Africa is 5.4; some countries have rates of 7.0.

A paper in the Lancet doesn't mince its words: “One of the consequences of the high total fertility rate is the migration crisis, which affects mainly sub-Saharan African countries and can also be observed in some countries from Central America.”

A study published yesterday warning of the climate emergency says that “the world population must be stabilised”. This paper is endorsed by 11,000 scientists, and shows in graphics how the steady increase in the human population has an impact on everything from from aircraft emissions to forest clearance. Yet still the authors skirt around the issue of what to do about it.

According to the BBC, as far as the UN is concerned, population growth is “too hot to handle”. And while David Attenborough doesn't shy away from the issue of population, the rest of us do. We have dropped the baton because human population growth, especially in poor countries, is a taboo subject.

I don't think it’s too hot to handle. I am advising individuals every day about contraception, and I want everyone in the world to have the same contraception service that my patients receive.

We all really care about the environment. So let's all stop pretending that human birth rates have nothing to do with it.

We all know humans cause animal populations to crash. Even certain species of flies are starting to be seen as endangered species. In the UK, our population has had massive environmental consequences. We have close to 67 million people living here, or 279 people per square kilometre; we have wiped out every living wild creature larger than a fox.

If you care about biodiversity, pristine forests and ocean creatures then you have to care about contraception. Don't think you are doing your bit for the environment just because you've stopped using plastic straws.

And if you are more concerned about people – about infant mortality, people dying in childbirth and women's access to education – then you have to care about contraception. This isn’t about western countries trying to force our ideas of family size on other cultures, it’s not eugenics and it's not forced sterilisation.

If women and communities can have access to contraception, they can make choices for themselves. Modern contraception use for women aged 15-49 is as low as 9% in some African countries. We get to make our choices; why don't we want women in poorer countries to get to make theirs?

I think the progesterone-only-pill should simply be available to buy over the counter everywhere. It’s entirely reversible and entirely safe. Taking any contraception is almost always safer than being pregnant – which, let's face it, is one of the most dangerous experiences most people will ever have.

So let’s keep talking about contraception, and save the world; save the environment, save biodiversity, and cut down on human misery. That excruciatingly embarrassing PSHE lesson we all had at school was brilliant for each of us as individuals, but it's not enough for today's purposes. We need to work out how we can help all countries have the same access to contraception that we have.

Global contraception must be taken off the list of taboo subjects. Together all countries of the world must face up to the damage we humans do with our ever-expanding numbers. We can't emigrate to the stars and other planets as the science fiction writers had it – but by making sure everyone has access to contraception, we can help save ourselves and the planet with some old-fashioned family planning.