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The fathers shall not be put to death for the children, neither shall the children be put to death for the fathers: every man shall be put to death for his own sin.” – Deuteronomy 24:16

Is having fewer children good for the environment? I don’t know the answer to that question. But I do know that recent “research” does not answer the question either. This junk science says you should have fewer kids.

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A tweet by Jill Filipovic started this whole thing. Ms. Filipovic said, “Having children is one of the worst things you can do for the planet.”

Ms. Filipovic’s tweet was based on a rave review in The Guardian. The “review” is mainly a puff piece for Kimberly Nicholas, the senior researcher on the project. Seth Wynes, her co-author, did much of the “research” as his Master’s thesis. Ms. Nicholas, of course, was his thesis adviser. Frankly, if Lund University is giving out graduate degrees for dreck like this, I pity their poor students.

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The “Research”

In a nutshell, here’s what Nicholas and Wynes did. They calculated annual per-capita CO₂ emissions for a variety of activities, including air travel, recycling, going vegan, buying only renewable energy, and so on. But when it came to kids, they did this:

For the action ‘have one fewer child,’ we relied on a study which quantified future emissions of descendants based on historical rates, based on heredity (Murtaugh and Schlax 2009). In this approach, half of a child’s emissions are assigned to each parent, as well as one quarter of that child’s offspring (the grandchildren) and so forth. This is consistent with our use of research employing the fullest possible life cycle approach in order to capture the magnitude of emissions decisions.

In other words they compared activities during a single year with CO₂ emissions over the life of the child. But they didn’t stop there. They basically created an infinite series based on the emissions of grandchildren, great-grandchildren, and so on.

Economists know something about this sort of thing. At the very least the researchers should have discounted future year emissions, creating what we might call the “present value of future CO₂ emissions.” But that’s irrelevant because they are comparing apples to oranges. They used annual emissions from air travel and other sources. They should have compared that with one year of emissions from a child.

Thanks to Rachel Lu

I must thank Rachel Lu. Her article at the National Review pointed me in this direction.

She begins with this delicious quote →

I can’t do justice to her excellent writing by paraphrasing, so I’ll just include a big chunk of her text:

The Lund study is not just a bleg about inefficient family cars or disposable diapers. It’s about visiting the emissions of the children on the fathers, ultimately convicting parents of the crime of perpetuating human civilization.

…

Parenthood, of course, isn’t the sort of thing you can step into and out of on a per annum basis. That’s the excuse for blaming parents for the projected carbon emissions of their child’s entire life, and then adding still more to that total based on projected grandchildren and great-grandchildren. They’re leaning on this cool concept that another team of climatologists dreamed up, called a “carbon legacy.” Each parent gets credited (or demerited) with half of every child’s projected lifetime emissions, a quarter of each projected grandchild’s projected emissions, and so forth down the generations. The cumulative total becomes your “legacy,” which is how we end up at the conclusion that childbearing is orders of magnitude worse than gas-guzzling, air travel, or the consumption of animal flesh.

Parents, on this evaluation, are worse offenders by far than the childless businessman who flies all over the country, sampling steakhouses and taking joyrides in private helicopters. The Lund study is not just a bleg about inefficient family cars or disposable diapers. It’s about visiting the emissions of the children on the fathers, ultimately convicting parents of the crime of perpetuating human civilization.

Comparing a year’s worth of road trips and beef jerky to the anticipated carbon output of your descendants in perpetuity is just silly on its face. That doesn’t even resemble an apples-to-apples comparison. Now, let’s engage in a little more armchair reflection. Quite recently, our friends on the left were beside themselves over the Paris accords and the Right’s refusal to get serious about climate change. We heard about echo chambers, false prophets, and the infamous conservative fact-aversion. Is there a chance that studies like this play some role in widespread skepticism about scientific claims? Perhaps what we have on our hands is a “crisis of scientific authority.”

Conclusion

The next time someone mentions “climate science” I plan to point them to this work. If climate scientists wonder why they are treated as a joke, it’s because they allow junk like this to be published. “Peer review” alone is not enough apparently.