Should a future parent consider the impact more people will have on the Earth? child via www.shutterstock.com

Earlier this summer, I found myself in the middle of a lively debate because of my work on climate change and the ethics of having children.

NPR correspondent Jennifer Ludden profiled some of my work in procreative ethics with an article entitled, “Should we be having kids in the age of climate change?,” which summarized my published views that we ought to consider adopting a “small family ethic” and even pursuing fertility reduction efforts in response to the threat from climate change. Although environmentalists for decades have worried about overpopulation for many good reasons, I suggest the fast-upcoming thresholds in climate change provide uniquely powerful reasons to consider taking real action to slow population growth.

Clearly, this idea struck a nerve: I was overwhelmed by the response in my personal email inbox as well as op-eds in other media outlets and over 70,000 shares on Facebook. I am gratified that so many people took the time to read and reflect on the piece.

Having read and digested that discussion, I want to continue it by responding to some of the most vocal criticisms of my own work, which includes research on “population engineering” – the intentional manipulation of human population size and structure – I’ve done with my colleagues, Jake Earl and Colin Hickey.

In short, the varied arguments against my views – that I’m overreacting, that the economy will tank and others – haven’t changed my conviction that we need to discuss the ethics of having children in this era of climate change.

How bad will things get?

Some comments – those claiming climate change is a hoax, devised by those who wish to control the world’s resources – are not worth responding to. Since 97 percent of all relevant experts cannot convince climate change skeptics of the basic scientific facts, then nothing I say will change their minds.

Other concerns, however, do require a response. Many people reacted to my work on procreation ethics by saying climate change will not be so bad, and so curbing individual desires, such as having children, in its name is unnecessary fear-mongering.

In my work, I suggest that 1.5-2 degrees Celsius warming over preindustrial levels will be “dangerous” and “very bad,” while 4 degrees C will be “catastrophic” and will leave large segments of the Earth “largely uninhabitable by humans.” Here is a very brief survey of the evidence for those claims based on what I consider reputable sources.