The global population debate has intensified as new data from 2024–2025 exposes a striking divide: while some countries are experiencing explosive population growth, others are shrinking faster than ever in modern history. This contrast raises a central question: has the world’s population increased or decreased? The reality, experts say, is both. The world crossed 8.1 billion people in early 2025, but the pace of growth has slowed dramatically, reaching its lowest rate since 1950. The turning point came when global fertility dropped to an average of 2.3 children per woman, with more than half of the world now living in countries below the replacement level of 2.1. This shift is creating two worlds: one where births are surging, and another where societies are aging into decline.
The sharpest declines are taking place in high-income and developed nations. The United Kingdom reported one of its lowest fertility rates in modern history in 2023, with England and Wales recording only 1.49 children per woman. Deaths have outnumbered births for several years, creating what demographers call a “natural decrease.” Scottish rural towns are already shrinking, while the British media described 2024 as a year of “rare population contraction” as deaths among older citizens surged. Japan remains the most dramatic example, with a fertility rate of 1.26 and nearly 30% of its population above 65.
For the seventeenth consecutive year, Japan recorded more deaths than births, with schools closing and entire villages disappearing. South Korea faces an even steeper crisis, posting the world’s lowest fertility rate, 0.72, which is far below what is required to sustain economic growth or maintain its workforce. China, once the world’s largest population, registered its second straight year of population decline in 2024 as its birth rate dropped to a historic low of 6.3 births per 1,000 people. Italy, Spain, Poland, and much of Eastern Europe are following similar patterns, driven by aging populations, low marriage rates, expensive childcare, and economic uncertainty among young people.
In contrast, population growth remains extremely high in parts of Africa and South Asia. Nigeria, Pakistan, Ethiopia, and Tanzania are witnessing rising birth rates, expanding economies, and younger demographics. Nigeria, currently at 223 million people, is projected to exceed 440 million by 2050, making it the world’s third-most-populated country. Pakistan adds nearly 4.2 million people every year, with fertility averaging 3.6 children per woman.
Ethiopia, Tanzania, and DR Congo also report rapidly growing populations due to high fertility, improved healthcare, declining infant mortality, and cultural norms that value larger families. This growth comes with massive challenges, including pressure on education systems, rising unemployment, urban overcrowding, and climate vulnerability, especially in megacities like Lagos and Karachi, which struggle with infrastructure demands.
Experts say the reasons behind the global demographic split vary widely. In shrinking societies, delayed marriages, increased education among women, expensive living costs, work-life pressures, and shifting values have lowered fertility. In Japan, young people increasingly avoid marriage altogether, while in South Korea, housing prices and job competition discourage family planning. Additionally, deaths are climbing due to aging populations, long-term health issues, and the lingering effects of the pandemic. In countries with rising populations, poverty, limited access to contraception, rural cultural traditions, and large-family preferences continue to fuel growth. Migration also reshapes demographics: Europe depends increasingly on migrants to sustain its workforce, while African nations experience large movements from rural to urban centers, accelerating city expansion.
The impact of these contrasting trends is profound. Shrinking regions are facing severe labor shortages, declining tax revenues, and higher pressure on pension and healthcare systems. Schools are consolidating, hospitals are overburdened, and businesses struggle to find workers. Economists warn that countries like Japan, South Korea, and Italy could lose global economic influence as their populations age rapidly. Meanwhile, rapidly growing countries face challenges of overcrowding, inflation, unemployment, water scarcity, and environmental degradation. Cities like Kampala, Dhaka, and Nairobi are struggling to build housing, transportation, and sanitation systems fast enough to keep up with demand.
Looking ahead, the UN predicts that global population growth will nearly stop by 2085 and could begin to decline after 2100. By mid-century, two-thirds of the world will live in low-fertility societies. At the same time, only a handful of countries, mostly in Africa, will drive global population increases. This divergence will reshape geopolitics, economic power, labor markets, immigration debates, and resource distribution. The future world will be defined not by a simple increase or decrease in population, but by a demographic divide that is widening each year.
In the end, the reality is clear: the world is simultaneously growing and shrinking. Some countries face a demographic crisis driven by too few births, while others struggle with the pressures of rapid expansion. Whether this becomes a global challenge or an opportunity depends on how governments respond with smarter policies, better childcare systems, sustainable development, and long-term planning for the generations ahead.
