Countries with the largest population 2021

In 2021, China remains the country with the largest population in the world, with more than 1.4 billion people. India has the second largest population in the world, with just under 1.4 billion inhabitants. With an estimated difference of fewer than 20 million people, experts predict that India will overtake China as the most populous nation on earth by the middle of the decade.

Global population

The total world population amounts to more than 7.8 billion people, and is expected to reach around 11 billion people by the end of the century. Due to improved healthcare, sanitation, and general living conditions, the global population continues to increase; mortality rates (particularly among infants and children) are decreasing and the median age of the world population has steadily increased for decades. As for the average life expectancy in industrial and developing countries, the gap has narrowed significantly since the mid-twentieth century. Asia is the most populous continent on Earth; 10 of the 20 largest countries are located there. It leads the ranking of the global population by continent by far, reporting four times as many inhabitants as Africa. Interestingly, the Americas are behind both Africa and Europe on this ranking, with Oceania reporting the lowest numbers of inhabitants.

The Demographic Transition

The population explosion over the past two centuries is part of a phenomenon known as the demographic transition. Simply put, this transition results from a drastic reduction in mortality, which then leads to a reduction in fertility, and increase in life expectancy; this interim period where death rates are low and birth rates are high is where this population explosion occurs, and population growth can remain high as the population ages. In the most-developed countries, the transition generally began with industrialization in the early-1800s, and growth has now stabilized as birth and mortality rates have re-balanced. Across less-developed countries, the stage of this transition varies; for example, China is at a later stage than India, which accounts for the predicted adjustments in the future. The least-developed region is Sub-Saharan Africa, where fertility rates remain at pre-industrial levels in some countries. Oftentimes, it is difficult to apply the demographic transition model on to individual countries, due to the influence of individual events, governmental interference, or societal trends. For example, the Second World War was followed by a fairly-global baby boom in the 1950s and 1960s, China's so-called "one-child policy" actively accelerated its reduction in fertility since the 1980s, and unhealthy lifestyles in some of the former-Eastern Bloc have kept life expectancy below levels seen in Western Europe.

The largest challenge to the world population, however, is climate change. As temperatures rise, droughts intensify, and extreme weather becomes more common, this puts a strain on the most vulnerable and under-developed countries; particularly those along the equator and island nations. Lower-income countries have historically struggled to adapt to booming populations in the same ways that high-income nations have, and the added challenges presented by climate change put further strain on infrastructure, national finances, and those who live there. Climate migration is another major demographic development that has emerged in recent decades, as people are forced from their homes by nature, not choice. It remains to be seen how the world's governments and international organizations will deal with the climate crisis, and whether populations in the most vulnerable countries will experience the same development as those in the richest.