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There's a lot of interesting discussion about fertility rates lately. At @ourworldindata.org, my colleague @sophiamersmann.bsky.social and I just built a new population simulation tool to help inform the conversation.

18/5/26, 5:03 am1 repost2 likes

AdyBee 🐝

@adybee.bsky.social

19 May

AdyBee 🐝@adybee.bsky.social

Every post about #FallingBirthRates …. #MemeForToday #CommentSection Just to be clear … falling birth rates are BAD for a number of reasons , and @jburnmurdoch.ft.com is correct about WHY they’re falling. #Smartphones

Daniel Bachler

@danielbachler.de

18 May

My colleague @hannahritchie.bsky.social used it to dig into an interesting question: South Korea's population is projected to fall from 52 million today to 22 million by 2100. What would it take to keep it stable instead? ourworldindata.org/south-koreas...

ourworldindata.orgSouth Korea’s population is set to shrink: what would it take to stop the decline?How much would fertility rates, life expectancy, or migration rates need to change to stop the population from shrinking?

Daniel Bachler

@danielbachler.de

18 May

In her piece, Hannah varies the three key inputs to the simulation one by one: Total Fertility Rate: children per woman, on average Life Expectancy: how long the average person lives Net Migration: immigrants minus emigrants

Daniel Bachler

@danielbachler.de

18 May

The tool then plots the population curve and age pyramid through 2100. It's deliberately simple so it can run in real time in your browser — and even so, given the same inputs, it matches UN projections closely for most countries.

Daniel Bachler

@danielbachler.de

18 May

Try it yourself for any country and build your own scenarios: ourworldindata.org/population-s...

ourworldindata.orgPopulation tool: how will populations across the world change in the 21st century?We created an interactive tool that lets you test how changes in fertility rates, life expectancy, and migration rates will change future populations.