The world's population first reached one billion people in 1805, and reached eight billion in 2022, and will peak at almost 10.2 billion by the end of the century. Although it took thousands of years to reach one billion people, it did so at the beginning of a phenomenon known as the demographic transition; from this point onwards, population growth has skyrocketed, and since the 1960s the population has increased by one billion people every 12 to 15 years. The demographic transition sees a sharp drop in mortality due to factors such as vaccination, sanitation, and improved food supply; the population boom that follows is due to increased survival rates among children and higher life expectancy among the general population; and fertility then drops in response to this population growth. Regional differences The demographic transition is a global phenomenon, but it has taken place at different times across the world. The industrialized countries of Europe and North America were the first to go through this process, followed by some states in the Western Pacific. Latin America's population then began growing at the turn of the 20th century, but the most significant period of global population growth occurred as Asia progressed in the late-1900s. As of the early 21st century, almost two-thirds of the world's population lives in Asia, although this is set to change significantly in the coming decades. Future growth The growth of Africa's population, particularly in Sub-Saharan Africa, will have the largest impact on global demographics in this century. From 2000 to 2100, it is expected that Africa's population will have increased by a factor of almost five. It overtook Europe in size in the late 1990s, and overtook the Americas a few years later. In contrast to Africa, Europe's population is now in decline, as birth rates are consistently below death rates in many countries, especially in the south and east, resulting in natural population decline. Similarly, the population of the Americas and Asia are expected to go into decline in the second half of this century, and only Oceania's population will still be growing alongside Africa. By 2100, the world's population will have over three billion more than today, with the vast majority of this concentrated in Africa. Demographers predict that climate change is exacerbating many of the challenges that currently hinder progress in Africa, such as political and food instability; if Africa's transition is prolonged, then it may result in further population growth that would place a strain on the region's resources, however, curbing this growth earlier would alleviate some of the pressure created by climate change.

According to latest figures, the Chinese population decreased by 1.39 million to around 1.408 billion people in 2024. After decades of rapid growth, China arrived at the turning point of its demographic development in 2022, which was earlier than expected. The annual population decrease is estimated to remain at moderate levels until around 2030 but to accelerate thereafter. Population development in China China had for a long time been the country with the largest population worldwide, but according to UN estimates, it has been overtaken by India in 2023. As the population in India is still growing, the country is very likely to remain being home of the largest population on earth in the near future. Due to several mechanisms put into place by the Chinese government as well as changing circumstances in the working and social environment of the Chinese people, population growth has subsided over the past decades, displaying an annual population growth rate of -0.1 percent in 2024. Nevertheless, compared to the world population in total, China held a share of about 17 percent of the overall global population in 2024. China's aging population In terms of demographic developments, the birth control efforts of the Chinese government had considerable effects on the demographic pyramid in China. Upon closer examination of the age distribution, a clear trend of an aging population becomes visible. In order to curb the negative effects of an aging population, the Chinese government abolished the one-child policy in 2015, which had been in effect since 1979, and introduced a three-child policy in May 2021. However, many Chinese parents nowadays are reluctant to have a second or third child, as is the case in most of the developed countries in the world. The number of births in China varied in the years following the abolishment of the one-child policy, but did not increase considerably. Among the reasons most prominent for parents not having more children are the rising living costs and costs for child care, growing work pressure, a growing trend towards self-realization and individualism, and changing social behaviors.

This statistic shows the total population of Brazil from 2020 to 2023, with a forecast through 2030. In 2023, the total population of Brazil was estimated at around 211.7 million inhabitants. Population of Brazil Brazil has a surprisingly low (and decreasing) population growth rate; despite it being home to the largest number of Catholics in the world, the majority of women in Brazil use some form of contraception, which is often government-subsidized or free, even though the Catholic Church retains its stance that the use of contraceptives is inherently wrong. Within the space of just one generation, families have gone from having more than six children to having just one or two, and the share of Catholics in the population is dwindling, too. The influence of 'telenovelas' — the overwhelmingly popular soap operas often with strong women figures and fewer than three children — could also be helping shape the population’s view of what an ideal family is. The fertility rate in Brazil fell below the replacement rate in 2006 and is still decreasing. The impending population imbalance in Brazil can be seen in the decreasing lower tier of the country’s age distribution. This follows a trend similar to the one Japan and many European countries are experiencing, which are now facing the problems of providing for an aging population with fewer young and working taxpayers. The trend is not quite as extreme in Brazil, giving it time to prepare for the fallout of decreasing family size. This preparation will be important to help the country maintain its emerging economic strength, which is watched with interest by many economists who have said that Brazil’s is one to watch — thus its position as one of the pillars of the “big four” BRIC countries.

According to a global survey conducted in 2021, three in 10 respondents had at least once spoken out against someone who was being prejudiced against LGBT+ people. In addition, some 13 percent attended a public event in support of LGBT+ people, e.g. a Pride march.