Natural habitats are being decimated, the world is growing hotter, and scientists fear we are experiencing the sixth mass extinction event in Earth's history. Under such circumstances, is it reasonable to bring a child into the world?

My philosophical research deals with environmental and procreative ethics – the ethics of choosing how many children to have or whether to have them at all. Recently, my work has explored questions where these two fields intersect, such as how climate change should affect decision-making about having a family.

Procreation is often viewed as a personal or private choice that should not be scrutinized. However, it is a choice that affects others: the parents, the children themselves and the people who will inhabit the world alongside those children in the future. Thus, it is an appropriate topic for moral reflection.

A lifelong footprint
Let's start by thinking about why it might be wrong to have a large family.

Many people who care about the environment believe they are obligated to try to reduce their impact: driving fuel-efficient vehicles, recycling and purchasing food locally, for example.

But the decision to have a child – to create another person who will most likely adopt a similar lifestyle to your own – vastly outweighs the impact of these activities. Based on the average distance a car travels each year, people in developed countries can save the equivalent of 2.4 metric tons of CO2 emissions each year by living without a vehicle, according to one literature review. For comparison, having one fewer child saves 58.6 metric tons each year.

So, if you think you are obligated to do other activities to reduce your impact on the environment, you should limit your family size, too.

In response, however, some people may argue that adding a single person to a planet of 8 billion cannot make a meaningful difference. According to this argument, one new person would constitute such a tiny percentage of the overall contribution to climate change and other environmental problems that the impact would be morally negligible.