The global population is growing rapidly, while the resources we depend on to live are dwindling. If you consider the footprint each person makes on the world – in terms of food and water consumed, electricity and gas used, and waste produced – the challenge of improving living standards while protecting natural resources and the environment is striking. The question of human population size is fundamentally one of sustainability, and in that so is the choice to have children.

Rather than being taboo, being childfree is something that should be celebrated and valued. The childfree do more for our environment than any campaign. In the UK our electricity use per capita is 5,407 kWh – it’s nigh on impossible to make up for the environmental footprint of having a child by remembering to switch off the lights. Finite resources mean we must consider our consumption now, what living standards are acceptable, and how to maintain the ecosystems on which we depend and how many of us there are.

Women are now as likely to be childless as to have three children. As social norms shift, a childfree lifestyle has become increasingly attractive, with career taking centre-stage for many thirtysomethings. Add to this rising living costs and you can see the clear benefits of not having children: the £250,000 required to raise each child is a challenge even for the most well-off.

In recent months, there has been ongoing speculation about those who do not have children: let’s call them ‘the childfree’, whether it’s Jennifer Aniston’s “baby bump” or conversations in the corridors of Westminster. Andrea Leadsom believed her credentials as a mother made her Prime Minister in-waiting, while Labour leadership candidate Owen Smith’s self-proclaimed normality stemmed from his “wife and two kids”. Being childfree is one of the oldest taboos, and it comes with a host assumed connotations: being less invested in the future or being ‘abnormal’ are but two.

There are, however, signs that things are changing. Our new Prime Minister became not only the second woman to fill the role, but the first to do so without being a mother. Leadsom’s alienating language backfired: the media and Twitterati rounded on those burnishing their ‘normal family’ credentials. It was May’s experience and competency that saw her become Prime Minister – her childfree status was, in the end, irrelevant.

Of course, having a family will always be a central part of life for many. The people who wish to have children but cannot need our empathy and support. But society should also acknowledge that those who choose not to have children are making a valuable contribution to a sustainable future.

Renewable energy is making waves in Europe

Our numbers have doubled in the last 50 years, transforming Earth into a ticking time bomb. Climate change is one devastating symptom of this surge. Population growth increases the number of wealthy carbon emitters and poorer climate change victims, while hampering mitigation and adaptation efforts.

Beyond environmental concerns, political instability, civil conflict and mass migration are an inevitable consequence. Young populations, high birth rates and rising life expectancy mean that, for instance, Africa’s population alone is expected to rise from one to four billion this century. While a global response is needed, industrialised countries like Britain, which consume more than their fair share of resources, must lead by example.

With the steady erosion of the childfree taboo, it is time to reopen the debate surrounding population growth and sustainability, educate young people about mindful consumption, and advocate improvements to family planning, sex education and women’s rights.

I will close with the wise words of actress and model Cameron Diaz: “I think women are afraid to say that they don’t want children because they’re going to get shunned. But I think that’s changing too now. I have more girlfriends who don’t have kids than those that do. And, honestly? We don’t need any more kids. We have plenty of people on this planet.”