I never intended to take several months off from writing. Life happened: buying a house, moving, celebrating a COVID-delayed wedding with family and friends, major back-to-back work deadlines, seemingly unending work travel, and parental health issues. I recently told a friend that I still feel like I’m recovering from the events of this summer. Except that I also felt that way in the fall, and it’s now almost the end of the year.
I’m turning 39 today. Those of us with late December birthdays understand the importance of making a big deal out of them, mostly because by this point in the year, everyone is tired, including me. I’ve spent the day tucked up in a cafe at a nice hotel on the waterfront, nursing cups of coffee and re-reading a book proposal I wrote in 2020 and 2021.
2022 had some big moments for studies of human population dynamics, climate change, and other big trends that impact our world. In mid-November, the UN estimated that the global human population reached 8 billion. The World Economic Forum has compiled multiple interesting charts to explore and explain this milestone (all images that follow can be found at that link). Here’s a chart you’ve likely seen before, putting this new population high in context:
Note how global population is estimated to have dipped following the Black Death’s medieval tour of Europe. Population growth really starts to pick up with the Industrial Revolution. Here’s a chart that puts the pace of population growth in context. Handily, it breaks down the periods during which population progressed by each billion, and how it’s projected to grow moving forward. This graph is based on UN population projections, and you’ll note that the UN estimated the world would hit 8 billion people some time between 2011 and 2024. Note, too, how population growth is projected to slow moving forward, even as total population increases:
The UN predicts that the global population will level out at 10.9 billion some time around 2100. Researchers from down the road at the University of Washington, however, project that by 2100, the global population could reach up to 8.8 billion people, or could shrink to 6.3 billion. Their research is available here, and it’s worth reading the summary of their findings. Here’s a graphic that summarizes the battle of the (estimated) billions:
Much of this debate (is the UN right? Is it wrong?) revolves around methodologies used to calculate population projections. Effectively, some demographers argue that the UN has been forecasting population growth rates that are too high. Beyond total figures, these conclusions from the UW researchers stood out to me:
“By 2050, 151 countries were forecasted to have a TFR lower than the replacement level (TFR <2.1), and 183 were forecasted to have a TFR lower than replacement by 2100. 23 countries in the reference scenario, including Japan, Thailand, and Spain, were forecasted to have population declines greater than 50% from 2017 to 2100; China's population was forecasted to decline by 48·0% (−6.1 to 68.4).”
TFR stands for Total Fertility Rate, or how many children a woman can expect to have in her lifetime if she lives to the end of her childbearing years and has children according to age-specific fertility rates. This is wild – 183 countries with TFR below replacement by 2100? Today, the UN recognizes 195 countries (if you’ve ever wondered, here's a handy explanation of how we get to that number), which really comes out to 193 plus two non-member observer states. One is the Vatican and the other is Palestine. So by 2100, if these authors are correct, 93.8% of countries globally could have a birthrate below replacement (and yes, the Vatican has a TFR of 0 and isn’t going to sway this calculation one way or the other, but I’ve kept it in to retain consistency with UN figures).
Among other factors, that decrease in birth rates, of course, is influenced by women’s access to education and urbanization. The authors use the UN Sustainable Development Goals as a marker here, and note that if SDGs are achieved, they are projected to reduce global population to a little north of 6 billion by 2100.
This is beyond interesting. In a world where 93.8% of countries are not reproducing at replacement rate (about 2.1 kids/woman), populations will decline nationally and globally. What would that look like? What would the politics be? What about geopolitical implications? How would we think and talk differently about growth if we were to experience this?
These are some of the questions I’m taking with me into 2023.