The OWID Brief: New population… | Our World in Data Summary

1. Key Themes

Theme 1: Demographic Collapse Is a Structural, Not Cyclical, Risk

Population decline is accelerating in specific markets, with downstream consequences for labor supply, housing, consumer demand, and public finance. South Korea is the sharpest example.

"South Korea…population is projected to more than halve by 2100, from 52 million today to just 22 million."

"Most countries are now below the 'replacement rate' of 2.1 children, and their populations are expected to shrink and age by the end of the century."

Theme 2: China's Clean Energy Buildout Is Operating at a Scale Most Analysts Underestimate

The absolute magnitude of China's solar and wind deployment in a single year dwarfs entire national grids — and it is already displacing fossil generation domestically.

"In 2025 alone, China's electricity generation increased by almost 500 terawatt-hours (TWh)…China effectively added a Germany-sized grid to its electricity system in just one year."

"China generated 340 TWh more electricity from solar than the year before. That's more than the UK and Spain, for example, generate from all sources each year."

"Low-carbon sources grew so much that coal power in China actually fell slightly."

Theme 3: Child Malnutrition Remains a Massive, Underpriced Global Problem

150 million children suffering from stunting represents a human capital deficit with compounding lifetime consequences — and proven intervention pathways exist.

"One in four children in the world today suffers from 'stunting'. That's 150 million children under five."

"A stunted child is too short for their age due to poor nutrition and frequent infections. Stunting suggests that their physical and cognitive development has been hindered, and the effects can last a lifetime."

Theme 4: The Fertility Decline Is Entering a New Phase — Driven by Social Disconnection, Not Just Economics

The mechanism behind falling birth rates has shifted, pointing to a new category of causal levers (and potential investment/policy responses).

"'In previous decades, the world's fertility rate went down because couples had fewer children. Now the main reason is that there are fewer couples.'"

"The most important driver of the recent decline, he argues, is smartphones and digital media, which affect the way young people socialize and couple."

Theme 5: Biofuel Growth Persists Alongside EV Adoption — Energy Transition Is Not Zero-Sum

The assumption that electrification crowds out legacy energy investments may be premature.

"Global biofuel production has grown sevenfold in the last 20 years, despite the rise of electric cars."

2. Contrarian Perspectives

Perspective 1: China's Coal Era May Already Be Ending — Not in the Future

Consensus framing treats China's coal peak as a future event. The data suggests it may have already arrived.

"Low-carbon sources grew so much that coal power in China actually fell slightly."

Combined with 500 TWh of new generation being almost entirely solar and wind, this implies the marginal unit of Chinese electricity demand is now being met by renewables — a structural, not incidental, shift.

Perspective 2: Fertility Decline Is a Technology Problem, Not Just an Economics Problem

Standard policy responses to falling fertility focus on housing subsidies, parental leave, and childcare. The article surfaces evidence that the primary driver may be digital behavior — which those interventions do not address.

"He notes several barriers to coupling, such as falling home ownership and a rise in young adults who live with their parents. But the most important driver of the recent decline, he argues, is smartphones and digital media, which affect the way young people socialize and couple."

"If digital media is indeed a major cause, it suggests a possible solution: changing our digital habits."

Perspective 3: Multifaceted Public Health Interventions Deliver Compounding Returns — Single-Issue Programs Do Not

Japan's stunting data shows that tackling disease alone produced modest results; combining nutrition and disease interventions tripled the rate of progress.

"Before World War II, Japan focused on tackling infectious diseases…Stunting declined at a moderate pace. After the war, they tackled both disease and diet…This multifaceted approach made progress nearly three times faster."

3. Companies Identified

Company	Description	Why Mentioned	Quote
Our World in Data	Nonprofit data publishing organization	Publisher of the newsletter and interactive demographic/energy tools	"The mission of Our World in Data is to increase understanding of the world's largest problems and drive informed action to solve them."
80,000 Hours	Nonprofit career advisory organization	Featured as a recommended resource for high-impact career planning, and as the source of a new book on AI and career strategy	"I've long recommended 80,000 Hours to anyone thinking about their career. I even found my role at Our World in Data through their job board!"

4. People Identified

Person	Description	Why Mentioned	Quote
Hannah Ritchie	Researcher/author at Our World in Data	Authored analysis on South Korea's demographic trajectory using the new population simulation tool	"Hannah Ritchie uses the tool to focus on South Korea, whose population is projected to more than halve by 2100."
Tuna Acisu	Researcher/author at Our World in Data	Co-authored the childhood stunting article examining Japan's success	"In a new article, Hannah Ritchie and Tuna Acisu answer these questions by zooming in on Japan."
Daniel Bachler	Developer/researcher at Our World in Data	Built the interactive population simulation tool	"Our colleagues Daniel Bachler and Sophia Mersmann built a population simulation tool."
Sophia Mersmann	Developer/researcher at Our World in Data	Co-built the interactive population simulation tool	"Our colleagues Daniel Bachler and Sophia Mersmann built a population simulation tool."
Benjamin Todd	Founder of 80,000 Hours; author	Published a new book on career strategy in the age of AI	"A new book by Benjamin Todd argues that most standard career advice has little research behind it, and doesn't account for how AI is changing the job market."
John Burn-Murdoch	Data journalist at the Financial Times	Authored analysis on the structural drivers of declining fertility, naming digital media as the primary cause	"'In previous decades, the world's fertility rate went down because couples had fewer children. Now the main reason is that there are fewer couples.'"
Pablo	Staff member at Our World in Data	Recommended 80,000 Hours and Benjamin Todd's book	"I've long recommended 80,000 Hours to anyone thinking about their career."
Charlie	Staff member at Our World in Data	Surfaced the John Burn-Murdoch fertility analysis	"If digital media is indeed a major cause, it suggests a possible solution: changing our digital habits."

5. Operating Insights

Insight 1: Use Scenario-Based Modeling, Not Point Estimates, for Long-Range Planning

The OWID population tool is a direct operational analog for any business doing long-range workforce, market sizing, or demand forecasting. Single-assumption projections (e.g., UN median) mask enormous variance.

"No one knows for sure how many children people will have decades from now, or how migration will shift. So it's worth asking what the population would look like if things turn out differently from what the UN or other demographers assume."

Insight 2: Compound Interventions Outperform Single-Lever Approaches by a Large Margin

For operators building health, education, or workforce development programs, Japan's stunting data is a direct argument for multi-pronged intervention design over siloed program execution.

"This multifaceted approach made progress nearly three times faster."

Insight 3: Use Concrete Physical Analogies to Communicate Scale

The newsletter's framing of China's 500 TWh electricity growth as "adding a Germany-sized grid in one year" is a powerful communication tactic — translating abstract data into intuitive comparisons that drive decision-making.

"China effectively added a Germany-sized grid to its electricity system in just one year."

6. Overlooked Insights

Insight 1: Tajikistan's Remittance Dependency Is an Extreme Case Worth Monitoring

Mentioned only in passing as a data headline, but a country where remittances approach 50% of GDP represents extreme macroeconomic fragility — relevant to investors in Central Asian markets, frontier debt, or remittance infrastructure.

"Tajikistan's remittances are worth nearly half the country's GDP."

Insight 2: Japan's Nuclear Restart Is Quietly Underway

Flagged only as a data bullet, but Japan's reversal on nuclear — after a near-total shutdown post-Fukushima — signals a broader global reconsideration of nuclear policy that has material consequences for uranium markets, energy security positioning, and utility investment.

"Japan closed nearly all of its nuclear plants after Fukushima, but some are coming back online."