Not a demographer, or a demographer’s son, but I can crunch your numbers ’til the demographer comes.

California has 39 million people in it. Our arbitrary planning horizon is 2050. In 2050, California is projected to have 60 million people in it. Growth in California is primarily from births (deaths and immigration are roughly even, pg 3). Obviously we value high individual autonomy in decisions as personal as procreation. But here’s something you might not know. A little under half the births in California are from unintended pregnancies (“women got pregnant sooner than they wanted, had not wanted to get pregnant then or in the future, or weren’t sure what they wanted”). Those are live births, not pregnancies.

Most people who do work on this stuff talk about the effects of unintended children on the parents. Here, I am going to speak to the resource costs of that population increase. I’d like to give you some equivalencies.

California has, roughly, 550,000 live births a year.

Of those, roughly, 46% were unintended. You know where this is going.

Every year, this state adds 253,000 kids whose parents did not want them then.

253,000 people is more than the City of Modesto, added every single year. If they follow usual urban water use patterns (which maybe they wouldn’t as young children, but the delay is likely only 15 years or so), that many people would use 63,000 acrefeet of water a year. That is the size of most medium-sized dams in the state (although not the yield of every dam in the state, because dams have a dead pool).  Every single year. For kids whose parents didn’t want to have them at that point.

If you project out to 2050*, the size gets staggering. By 2050, the difference from not having any unwanted children would be about 9 million people. In 2050, I am sure that water managers would be very grateful if they only have to supply water to 50 million people instead of 60 million people. The difference is the population of the Bay Area plus the San Fernando Valley. It is twenty city of Fresnos. Now you are talking water volumes roughly on the order of Oroville Dam, or California’s share of the Colorado River, or what you could get if agriculture shrinks by a third. Addressing population directly is non-trivial.

When you are talking about climate change and emissions, the story is even starker. Every person consumes water and every person causes greenhouse gas emissions, but greenhouse gas emissions have a cumulative effect that matter over time. Greenhouse gases emitted now hurt us more than greenhouse gases emitted in five years. In the year 2050, delayed emissions means less sea level rise, slightly cooler nights, slightly larger snowpacks. Averted people would reduce emissions, but even postponed people would help.

This stuff gets brought up awkwardly at meetings, then we all retreat. But controlling population has profound implications for California’s resource use and climate. We should face it head on.







*There must be all sorts of problems projecting out to 2050. Presumably some of the kids who aren’t wanted in this year become wanted in future years as the parents’ circumstances change. On the other hand, there’s a generation and a half between now and 2050, and all the kids averted now will have no future kids. I will do the grossest of simplifications and hope that no demographers are reading. Thus:

(Population in 2050 – Population now)(Percent of births that are unwanted) = Number of people who shouldn’t exist in California in 2050
(59 million people – 39 million people)(0.46) = 9.2 million averted people in 2050

Look, I’m sure this is wrong. But I could be very wrong and it would still be staggering. If I am wrong by two, you are still talking 4.6 million people. If I’m off by an order of magnitude, you are still talking about a million people. If you ask any water manager in the state if he wants to find water for an extra million people, the answer will be NO.


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4 responses to “Not a demographer, or a demographer’s son, but I can crunch your numbers ’til the demographer comes.

  1. It seems to me the biggest challenge to addressing this issue of population growth through births is social and cultural. I think any effort that to limit the ability of people to procreate at will, or even discourage, would be met with resistance from all parts of the political spectrum. Making birth control more readily available might be helpful, but not that much. It’s not like it’s terribly hard in California to access it today.

    I think also it is possible if not likely that unintended does not correlate to unwanted near as much as you are suggesting here. People generally like their own kids despite whether or not they planned them or not when they are born if not sooner. It’s always some other couple that should have thought twice before reproducing.

    Your points about the resource issues are well taken, but I think the limiting population growth will be a tough slog.

  2. onthepublicrecord

    People generally like their own kids despite whether or not they planned them

    Very true. But people who didn’t intend to have children this year wouldn’t miss them if they didn’t have them. Then they would love the ones they had four years later.

    California seems to be doing as much as any state is doing. But the comparison isn’t other states, or current efforts. The comparison is how hard it will be to adapt to climate change. Everything is going to be a tough slog. We should put all the tough slogs on the table and choose between them.

  3. horatiox

    Number of people who shouldn’t exist in California in 2050

    h mplmnt Glg McMgns, mndtry brtn, nd strlztn SP, nd np t n th bd.

    Serio, the key issue concerns politics, and the politics of “Freedom,” as much as it concerns resources such as H20. Had academics listened to neo-behaviorists, and even BF Skinner (who favored family planning of all sorts), instead of the Chomskys, and lefto-libertarians of various sorts (see the daily unfogged drivel for examples), the population disaster would have been prevented.

    Planning–whether in terms of population control, water issues, property, econ., etc– suggests socialism to many humans (even liberals), and so many reject it out of hand. Planners are not exactly romantic heroes, but pencil-pushing bureaucrats and nerds: Ds M dsn’t wnt t scrw Rlph Ndr; sh wnts t scrw DNr’s, f vrs srts. S t gs.

    [Partially disemvoweled by moderater]

  4. ptm

    You know about the Kaya Identity? It (being an identity and all) is analytically pretty trivial, but is a neat little framework for thinking about these things.
    CO2 = pop * GDP/pop * energy / GDP * CO2/energy

    Think about small changes and you can just add up the growth rates to get a net. I really like it as a conceptual tool.

    Yes, this is no-longer-Utah Pete.