Anna Hughes doesn’t fly in aeroplanes, doesn’t own a car, eats a vegan diet, runs her home on solar energy, shops at a refill supermarket, uses a non-flushable compost toilet, and doesn’t wash her hair to save water.
But one of the biggest life decisions she has made in a bid to reduce her impact on the planet is not having children.
Hughes, 38, from Hertfordshire, first came to the realisation she didn’t want to be a mother at university after learning about the climate crisis.
“I learned that there was an environmental impact to having children and I didn't want to contribute to that,” she tells Yahoo Life UK. “I understood living in a low carbon way [went] beyond having low energy lightbulbs.”
There have been points when Hughes has been more tempted, describing it as a sliding scale – “nothing is black and white” – but on balance she still believes it is the right choice, a decision she says her family and friends respect.
Of course she gets some, predictable, criticism - that she will die alone or have no one to care for her in old age.
“I do have a family,” she responds. “I imagine I will have a husband at some point. Some people with children die alone!”
Watch: UK's Johnson says world must face climate change
Four in 10 young people around the world are hesitant to have children as a result of the climate crisis and fear that governments are doing too little, a poll of 10,000 published in September, found.
A smaller study from 2020 found 96% of those aged 27 to 45 were concerned about their potential future children living in a climate-changed world.
The total number of humans currently living is 7.8 billion as of January 2021. Although the rate of growth is predicted to slow, the government predicts we will reach 9.7 billion by 2050 and 10.9 billion by 2100. In the UK that will be 69.6 million by mid-2029 and 72 million by mid-2041, says the Office for National Statistics (ONS).
Read more: 6 things you can do to slow climate change
Having one fewer child in the developed world saves 58.6 tonnes of carbon every year, according to a 2017 study. The research also recommended living car free, avoiding plane travel and eating a plant-based diet but even doing all these things only totals a rough annual reduction of 4.8 tonnes. It is clear not having a child has a much greater impact by that metric.
High profile figures like Prince Harry and Meghan Markle have publicly committed to only having two children - a figure that, in population terms, replaces the parents - while US politician Alexandria Ocasio Cortez described herself in 2019 as “a woman whose dreams of motherhood now taste bittersweet because of what I know about our children’s future”.
David Attenborough was more explicit about the need for a reduction in population size. The BBC presenter said in a 2018 Newsnight show: “In the long run, population growth has to come to an end.”
Attenborough is a patron of charity Population Matters, which campaigns to achieve a sustainable human population. Other UK groups have emerged like BirthStrike, founded to bring together those rejecting motherhood for the climate (although it has now been closed).
Lea, whose adult son lives in Brighton, says she doesn't think she will have grandchildren now: “[My son and his wife] had originally wanted children but talked about wanting less and less to bring a child into this world due to many problems facing us; political but mainly the climate.”
Others told Yahoo Like UK they had already had one birth child but wouldn’t be having more, saying it would not be fair to do so given the potentially perilous state of the climate.
But Jenny Brown, author of Birth Strike: The Hidden Fight Over Women’s Work, says she rejects not having children as the solution. “There's a larger problem with looking at climate change as a population issue...looking at it on an individual basis rather than a society-wide basis.
“[As] something an individual can do, not have children or use less energy in various ways, instead of looking at where the power lies in perpetuating the problem - in fossil fuel corporations and their allied banks and investors and [where] the power for a solution lies in massive government action to constrain these powerful corporations”.
Hughes says she sees the logic of such arguments but feels “we as individuals are part of the system - one of the reasons why fossil fuel companies emit so much is because we buy their products, we drive the cars they fuel... our choices do make a difference”. She advocates people looking more at alternative means of having a family - like adoption.
As the western world begins to feel the sharper end of the climate crisis that developing nations have felt for years - extreme weather events and rising sea levels - media coverage is growing and governments are slowly starting to implement policy.
But even this wake up call does not reassure many still unsure about parenthood. Hughes says: “[The] capability of this planet to look after us is limited, that is a mathematical fact. We can’t just keep on churning them out.”