For decades, population growth has been portrayed as one of humanity’s greatest environmental challenges. Policymakers, scientists, and environmentalists have often argued that a larger population places greater pressure on natural resources, increases energy demand, and accelerates carbon emissions. A United Nations survey of 50 Nobel laureates found that more than a third considered population growth and environmental degradation to be among the world’s biggest challenges. The world’s population has more than tripled since the 1950s, reaching nearly 7.8 billion in 2020, and is projected to exceed 8.5 billion by 2030.
At first glance, the conclusion seems obvious: slower population growth should reduce pressure on the environment. However, the relationship between population and environmental impact is more complex than it appears. While the global population continues to grow, many countries are now entering an era of demographic decline. According to United Nations projections, dozens of countries will experience shrinking populations in the coming decades. Europe is already witnessing this trend, while Latin America and Asia are expected to experience this in the 2050s. Japan offers one of the clearest examples. The country recorded its first population decline in the 2015 census and has continued to shrink since then.
Has Japan’s population decline significantly reduced its energy consumption? To some extent, yes. According to data from the International Energy Agency (IEA), Japan’s electricity generation in 2024 was about 8 per cent lower than in 2000, while per capita electricity consumption declined by about 6 per cent. Yet these changes do not tell the full story. According to the scholars, the contribution of population decline to a decrease in energy consumption in Japan is limited; in the future, population decline may induce an increase in energy consumption due to the lack of productive labour, and the country may substitute capital to maintain a certain level of production.
The limitations of population-based explanations become even clearer when comparing countries with similar population sizes but vastly different energy use levels. A study by Boston University’s Institute for Global Sustainability found that Canada and Uganda have roughly similar populations, yet Canada consumes about 167 times more energy than Uganda. Likewise, although the Philippines has a population nearly 38 times larger than Qatar’s, the two countries consume comparable amounts of energy. An average Qatari uses nearly 195 megawatt-hours of energy annually, while an average Filipino uses only about 5 megawatt-hours. Similarly, China, which held the title of world’s most populous country until last year, when India surpassed it, experienced its first population decline in 2022.
Earlier this year, China’s statistics bureau showed that the country’s birth rate fell to 5.6 births per 1000 people, the lowest rate ever. Though its fertility rate is falling, its economy still grew by 5 per cent last year. Its electricity demand is expected to rise again in 2026, and it is still the world’s single largest emitter of CO2. These comparisons highlight an important reality: environmental impact is influenced not only by the number of people but also by how people live; their lifestyle matters more. Economists often describe this relationship through the IPAT framework, which states that environmental impact is shaped by population, affluence, and technology.
Population matters, but rising income levels and consumption patterns can increase environmental pressures even when population growth slows. India is a good example of this trend. As a developing country, India is using more and more energy as its economy grows. According to the International Energy Agency (IEA), energy use per person in India increased by 207 per cent between 2000 and 2024. Even though India’s population is expected to start shrinking in the 2060s, India’s fertility rate has already fallen to 1.9, below the replacement level of 2.1 needed to stabilise population size, and experts think energy demand may continue to grow.
India’s population increased from about 870 million in 1990 to around 1.45 billion in 2025. During the same period, GDP per person rose from $371 to $2,695, and electricity use per person increased from 0.27 MWh to 1.46 MWh. In other words, while the population grew by only about 70 per cent, income per person increased more than eight times, and electricity use per person increased more than five times. This pattern is likely to continue in the coming decades. Although India’s population is expected to peak and begin declining sometime after the 2060s, energy demand may continue to rise as incomes increase and more households gain access to energy-intensive goods and services.
As people become wealthier, they tend to purchase more appliances and electronic devices, travel more frequently, consume more resource-intensive products, and demand higher levels of comfort at home and at work. The growth of air conditioning illustrates this trend. Rising incomes and increasing temperatures are expected to drive a dramatic increase in air-conditioner ownership across developing countries. India is projected to experience one of the largest increases in cooling demand over the next few decades. Similarly, global air travel is expected to continue expanding as incomes rise and more people enter the middle class.
These changes are driven less by population growth than by rising consumption. The environmental challenge of the 21st century is therefore not simply about how many people inhabit the planet. It is about how societies produce and consume energy, how technologies evolve, and how living standards improve. Population is an important variable, but affluence and lifestyle choices often multiply its effects.
The most effective solution is not merely slower population growth but the creation of cleaner energy systems, more efficient technologies, sustainable cities, and consumption patterns that reduce environmental pressures without compromising human development. Population changes slowly on its own, but lifestyle is something that policies, technology, and our choices can change. That is where the greatest opportunities for addressing climate change and resource stress are likely to be found.
(The writers are Assistant Professors, Department of Economics, CHRIST (Deemed to be University), Bangalore)