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.

Until the 1800s, population growth was incredibly slow on a global level. The global population was estimated to have been around 188 million people in the year 1CE, and did not reach one billion until around 1803. However, since the 1800s, a phenomenon known as the demographic transition has seen population growth skyrocket, reaching eight billion people in 2023, and this is expected to peak at over 10 billion in the 2080s.

Between 1800 and 2021, the total population of each continent experienced consistent growth, however as growth rates varied by region, population distribution has fluctuated. In the early 19th century, almost 70 percent of the world's population lived in Asia, while fewer than 10 percent lived in Africa. By the end of this century, it is believed that Asia's share will fall to roughly 45 percent, while Africa's will be on course to reach 40 percent. 19th and 20th centuries Fewer than 2.5 percent of the world's population lived in the Americas in 1800, however the demographic transition, along with waves of migration, would see this share rise to almost 10 percent a century later, peaking at almost 14 percent in the 1960s. Europe's share of the global population also grew in the 19th century, to roughly a quarter in 1900, but fell thereafter and saw the largest relative decline during the 20th century. Asia, which has consistently been the world's most populous continent, saw its population share drop by the mid-1900s, but it has been around 60 percent since the 1970s. It is important to note that the world population has grown from approximately one to eight billion people between 1800 and the 2020s, and that declines in population distribution before 2020 have resulted from different growth rates across the continents. 21st century Africa's population share remained fairly constant throughout this time, fluctuating between 7.5 and 10 percent until the late-1900s, but it is set to see the largest change over the 21st century. As Europe's total population is now falling, and it is estimated that the total populations of Asia and the Americas will fall by the 2050s and 2070s respectively, rapid population growth in Africa will see a significant shift in population distribution. Africa's population is predicted to grow from 1.3 to 3.9 billion people over the next eight decades, and its share of the total population will rise to almost 40 percent. The only other continent whose population will still be growing at this time will be Oceania, although its share of the total population has never been more than 0.7 percent.

The earliest point where scientists can make reasonable estimates for the population of global regions is around 10,000 years before the Common Era (or 12,000 years ago). Estimates suggest that Asia has consistently been the most populated continent, and the least populated continent has generally been Oceania (although it was more heavily populated than areas such as North America in very early years). Population growth was very slow, but an increase can be observed between most of the given time periods. There were, however, dips in population due to pandemics, the most notable of these being the impact of plague in Eurasia in the 14th century, and the impact of European contact with the indigenous populations of the Americas after 1492, where it took almost four centuries for the population of Latin America to return to its pre-1500 level. The world's population first reached one billion people in 1803, which also coincided with a spike in population growth, due to the onset of the demographic transition. This wave of growth first spread across the most industrially developed countries in the 19th century, and the correlation between demographic development and industrial or economic maturity continued until today, with Africa being the final major region to begin its transition in the late-1900s.

In the past four centuries, the population of the Thirteen Colonies and United States of America has grown from a recorded 350 people around the Jamestown colony in Virginia in 1610, to an estimated 346 million in 2025. While the fertility rate has now dropped well below replacement level, and the population is on track to go into a natural decline in the 2040s, projected high net immigration rates mean the population will continue growing well into the next century, crossing the 400 million mark in the 2070s. Indigenous population Early population figures for the Thirteen Colonies and United States come with certain caveats. Official records excluded the indigenous population, and they generally remained excluded until the late 1800s. In 1500, in the first decade of European colonization of the Americas, the native population living within the modern U.S. borders was believed to be around 1.9 million people. The spread of Old World diseases, such as smallpox, measles, and influenza, to biologically defenseless populations in the New World then wreaked havoc across the continent, often wiping out large portions of the population in areas that had not yet made contact with Europeans. By the time of Jamestown's founding in 1607, it is believed the native population within current U.S. borders had dropped by almost 60 percent. As the U.S. expanded, indigenous populations were largely still excluded from population figures as they were driven westward, however taxpaying Natives were included in the census from 1870 to 1890, before all were included thereafter. It should be noted that estimates for indigenous populations in the Americas vary significantly by source and time period. Migration and expansion fuels population growth The arrival of European settlers and African slaves was the key driver of population growth in North America in the 17th century. Settlers from Britain were the dominant group in the Thirteen Colonies, before settlers from elsewhere in Europe, particularly Germany and Ireland, made a large impact in the mid-19th century. By the end of the 19th century, improvements in transport technology and increasing economic opportunities saw migration to the United States increase further, particularly from southern and Eastern Europe, and in the first decade of the 1900s the number of migrants to the U.S. exceeded one million people in some years. It is also estimated that almost 400,000 African slaves were transported directly across the Atlantic to mainland North America between 1500 and 1866 (although the importation of slaves was abolished in 1808). Blacks made up a much larger share of the population before slavery's abolition. Twentieth and twenty-first century The U.S. population has grown steadily since 1900, reaching one hundred million in the 1910s, two hundred million in the 1960s, and three hundred million in 2007. Since WWII, the U.S. has established itself as the world's foremost superpower, with the world's largest economy, and most powerful military. This growth in prosperity has been accompanied by increases in living standards, particularly through medical advances, infrastructure improvements, clean water accessibility. These have all contributed to higher infant and child survival rates, as well as an increase in life expectancy (doubling from roughly 40 to 80 years in the past 150 years), which have also played a large part in population growth. As fertility rates decline and increases in life expectancy slows, migration remains the largest factor in population growth. Since the 1960s, Latin America has now become the most common origin for migrants in the U.S., while immigration rates from Asia have also increased significantly. It remains to be seen how immigration restrictions of the current administration affect long-term population projections for the United States.

It is presumed that the first humans migrated from Siberia to North America approximately twelve thousand years ago, where they then moved southwards to warmer lands. It was not until many centuries later that humans returned to the north and began to settle regions that are now part of Canada. Despite a few short-lived Viking settlements on Newfoundland around the turn of the first millennium CE, the Italian explorer Giovanni Caboto (John Cabot), became the first European to explore the coast of North America in the late 1400s. The French and British crowns both made claims to areas of Canada throughout the sixteenth century, but real colonization and settlement did not begin until the early seventeenth century. Over the next 150 years, France and Britain competed to take control of the booming fur and fishing trade, and to expand their overseas empires. In the Seven Year's War, Britain eventually defeated the French colonists in North America, through superior numbers and a stronger agriculture resources in the southern colonies, and the outcome of the war saw France cede practically all of it's colonies in North America to the British.

Increased migration and declining native populations

The early 1800s saw a large influx of migrants into Canada, with the Irish Potato Famine bringing the first wave of mass-migration to the country, with further migration coming from Scandinavia and Northern Europe. It is estimated that the region received just shy of one million migrants from the British Isles alone, between 1815 and 1850, which helped the population grow to 2.5 million in the mid-1800s and 5.5 million in 1900. It is also estimated that infectious diseases killed around 25 to 33 percent of all Europeans who migrated to Canada before 1891, and around a third of the Canadian population is estimated to have emigrated southwards to the United States in the 1871-1896 period. From the time of European colonization until the mid-nineteenth century, the native population of Canada dropped from roughly 500,000 (some estimates put it as high as two million) to just over 100,000; this was due to a mixture of disease, starvation and warfare, instigated by European migration to the region. The native population was generally segregated and oppressed until the second half of the 1900s; Native Canadians were given the vote in 1960, and, despite their complicated and difficult history, the Canadian government has made significant progress in trying to include indigenous cultures in the country's national identity in recent years. As of 2020, Indigenous Canadians make up more than five percent of the total Canadian population, and a higher birth rate means that this share of the population is expected to grow in the coming decades.

Independence and modern Canada

Canadian independence was finally acknowledged in 1931 by the Statute of Westminster, putting it on equal terms with the United Kingdom within the Commonwealth; virtually granting independence and sovereignty until the Canada Act of 1982 formalized it. Over the past century, Canada has had a relatively stable political system and economy (although it was hit particularly badly by the Wall Street Crash of 1929). Canada entered the First World War with Britain, and as an independent Allied Power in the Second World War; Canadian forces played pivotal roles in a number of campaigns, notably Canada's Hundred Days in WWI, and the country lost more than 100,000 men across both conflicts. The economy boomed in the aftermath of the Second World War, and a stream of socially democratic programs such as universal health care and the Canadian pension plan were introduced, which contributed to a rise in the standard of living. The post war period also saw various territories deciding to join Canada, with Newfoundland joining in 1949, and Nunavut in 1999. Today Canada is among the most highly ranked in countries in terms of civil liberties, quality of life and economic growth. It promotes and welcomes immigrants from all over the world and, as a result, it has one of the most ethnically diverse and multicultural populations of any country in the world. As of 2020, Canada's population stands at around 38 million people, and continues to grow due to high migration levels and life expectancy, and a steady birth rate.

description: The Anthropogenic Biomes of the World, Version 2: 1800 data set describes anthropogenic transformations within the terrestrial biosphere caused by sustained direct human interaction with ecosystems, including agriculture and urbanization c. 1800. Potential natural vegetation, biomes, such as tropical rainforests or grasslands, are based on global vegetation patterns related to climate and geology. Anthropogenic transformation within each biome is approximated using population density, agricultural intensity (cropland and pasture) and urbanization. This data set is part of a time series for the years 1800, 1800, 1900, and 2000 that provides global patterns of historical transformation of the terrestrial biosphere during the Industrial Revolution.; abstract: The Anthropogenic Biomes of the World, Version 2: 1800 data set describes anthropogenic transformations within the terrestrial biosphere caused by sustained direct human interaction with ecosystems, including agriculture and urbanization c. 1800. Potential natural vegetation, biomes, such as tropical rainforests or grasslands, are based on global vegetation patterns related to climate and geology. Anthropogenic transformation within each biome is approximated using population density, agricultural intensity (cropland and pasture) and urbanization. This data set is part of a time series for the years 1800, 1800, 1900, and 2000 that provides global patterns of historical transformation of the terrestrial biosphere during the Industrial Revolution.

In 1800, the region of present-day Turkey had a population of approximately 9.8 million. Turkey’s population would grow steadily throughout the 1800s, growing to 14 million by the turn of the century. During this time, Turkey was the center of the Ottoman Empire, which also covered much of the Balkans, Arabia, and the African coast from Libya to Somalia. In the early 20th century, the Ottoman Empire's dissolution period began, characterized by political instability and a series of military defeats and coups. The empire was one of the defeated Central Powers of the First World War, in which it suffered approximately three million total fatalities. It is estimated that the majority of these deaths did not come directly from the war, but as a result of the government-orchestrated mass expulsion and genocide of non-Turks from within the Turkish borders, specifically Armenians, Assyrians, Greeks and Kurds; many ethnic Turks were simultaneously expelled from neighboring countries, namely Greece, which makes these events less-visible when examining annual data, although Turkey's total population did drop by one million between 1914 and 1924.

The Republic of Turkey Following the end of the Turkish War of Independence in 1923, and the establishment of the republic of Turkey, the population would begin to recover, tripling from just around 21 million in 1950 to over 63 million by the turn of the century. The new republic, led by Mustafa Kemal Atatürk, introduced sweeping, progressive reforms that modernized the country, particularly its healthcare and education systems. Turkey remained neutral throughout the Second World War, and became a member of NATO during the Cold War. The second half of the 1900s was marked with intermittent periods of political instability, and a number of military conflicts (namely, in Cyprus and Kurdistan). In spite of this, Turkey has generally been considered a developed country for most of this time, although its life expectancy and infant mortality rates have often been more in line with developing nations.

Modern Turkey In the past decade, Turkey's population growth has continued its rapid growth; while birth rates have declined, the mass migration of refugees to the country fleeing the Syrian Civil War has seen the population growth ramain high. This influx of refugees was seen as a stepping stone in Turkey's accession to the European Union, with whom it has been negotiating a potential membership since 2005. Accession to the EU would provide huge economic benefits to Turkey, however, political developments in recent years (particularly the 2016 coup) have seen these negotiations stall, as the EU has accused the Turkish government of committing widespread human rights violations, such as torture, political imprisonment and censorship of free speech. In 2020, Turkey's population is estimated to be over 84 million people, and is expected to exceed 100 million in the next two decades.

In 1800, the population of the region of present-day India was approximately 169 million. The population would grow gradually throughout the 19th century, rising to over 240 million by 1900. Population growth would begin to increase in the 1920s, as a result of falling mortality rates, due to improvements in health, sanitation and infrastructure. However, the population of India would see it’s largest rate of growth in the years following the country’s independence from the British Empire in 1948, where the population would rise from 358 million to over one billion by the turn of the century, making India the second country to pass the billion person milestone. While the rate of growth has slowed somewhat as India begins a demographics shift, the country’s population has continued to grow dramatically throughout the 21st century, and in 2020, India is estimated to have a population of just under 1.4 billion, well over a billion more people than one century previously. Today, approximately 18% of the Earth’s population lives in India, and it is estimated that India will overtake China to become the most populous country in the world within the next five years.

Additional file 3: Data from the analysis of isoform- 1 and isoform- 8 of TP53 human gene.

Humans have been living on the continent of Australia (name derived from "Terra Australis"; Latin for "the southern land") for approximately 65,000 years, however population growth was relatively slow until the nineteenth century. Europeans had made some contact with Australia as early as 1606, however there was no significant attempt at settlement until the late eighteenth century. By 1800, the population of Australia was approximately 350,000 people, and the majority of these were Indigenous Australians. As colonization progressed the number of ethnic Europeans increased while the Australian Aboriginal population was decimated through conflict, smallpox and other diseases, with some communities being exterminated completely, such as Aboriginal Tasmanians. Mass migration from Britain and China After the loss of its American colonies in the 1780s, the British Empire looked to other parts of the globe to expand its sphere of influence. In Australia, the first colonies were established in Sydney, Tasmania and Western Australia. Many of these were penal colonies which became home to approximately 164,000 British and Irish convicts who were transported to Australia between 1788 and 1868. As the decades progressed, expansion into the interior intensified, and the entire country was claimed by Britain in 1826. Inland colonization led to further conflict between European settlers and indigenous Australians, which cost the lives of thousands of natives. Inward expansion also saw the discovery of many natural resources, and most notably led to the gold rushes of the 1850s, which attracted substantial numbers of Chinese migrants to Australia. This mass migration from non-European countries eventually led to some restrictive policies being introduced, culminating with the White Australia Policy of 1901, which cemented ethnic-European dominance in Australian politics and society. These policies were not retracted until the second half of the 1900s. Independent Australia Australia changed its status to a British dominion in 1901, and eventually became independent in 1931. Despite this, Australia has remained a part of the British Commonwealth, and Australian forces (ANZAC) fought with the British and their Allies in both World Wars, and were instrumental in campaigns such as Gallipoli in WWI, and the South West Pacific Theater in WWII. The aftermath of both wars had a significant impact on the Australian population, with approximately 90 thousand deaths in both world wars combined, as well as 15 thousand deaths as a result of the Spanish flu pandemic following WWI, although Australia experienced a significant baby boom following the Second World War. In the past fifty years, Australia has promoted immigration from all over the world, and now has one of the strongest economies and highest living standards in the world, with a population that has grown to over 25 million people in 2020.

Additional file 7: Data from the analysis on gain-of-function mutations.

Despite massive global conservation strategies, tiger populations continued to decline until recently, mainly due to habitat loss, human-animal conflicts, and poaching. These factors are known to affect the genetic characteristics of tiger populations and decrease local effective population sizes. The Terai Arc Landscape (TAL) at the foothills of the Himalaya is one of the 42 source sites of tigers around the globe. Therefore, information on how landscape features and anthropogenic factors affect the fine-scale spatial genetic structure and variation of tigers in TAL is needed to develop proper management strategies for achieving long-term conservation goals. We document, for the first time, the genetic characteristics of this tiger population by genotyping 71 tiger samples using 13 microsatellite markers from the western region of TAL (WTAL) of 1800 km2. Specifically, we aimed to estimate the genetic variability, population structure, and gene flow. The microsatellite markers indicated that the levels of allelic diversity (MNA = 6.6) and genetic variation (Ho = 0.50, HE = 0.64) were slightly lower than those reported previously in other Bengal tiger populations. We observed moderate gene flow and significant genetic differentiation (FST= 0.060) and identified the presence of cryptic genetic structure using Bayesian and non-Bayesian approaches. There was low and significantly asymmetric migration between the two main subpopulations of the Rajaji Tiger Reserve and the Corbett Tiger Reserve in WTAL. Sibship relationships indicated that the functionality of the corridor between these subpopulations may be retained if the quality of the habitat does not deteriorate. However, we found that gene flow is not adequate in view of changing land use matrices. We discuss the need to maintain connectivity by implementing the measures that have been suggested previously to minimize the level of human disturbance, including relocation of villages and industries, prevention of encroachment, and banning sand and boulder mining in the corridors.

From 1273 until 1918, Austria was the seat of power of the House of Habsburg; one of Europe's most powerful and influential royal families of the past millennium. During this time and in the subsequent century since the Austro-Hungarian Empire's dissolution, the borders and demography of the Austrian state have changed dramatically, with the population growing from approximately three million people in 1800 to just over nine million in 2020. The area of modern Austria's population rose gradually throughout the nineteenth century, until the early 1900s, where it then dropped and fluctuated during the World Wars, before rising again until recent years.

End of an empire

The assassination of the heir to the Austrian throne, Archduke Franz Ferdinand, in Sarajevo on June 28, 1914, caused Austria to declare war on Serbia, which marked the outbreak of the First World War. The war (and subsequent Spanish Flu pandemic) would see the deaths of more than 1.2 million people from the Austro-Hungarian Empire, and the area of modern Austria's population dropped by almost 400,000 people between 1916 and 1920. In the years preceding the First World War, Slavic nationalism and tensions between various ethnicities in the empire had escalated to a new level; following the dissolution of Austria-Hungary in 1918, new states such as Poland, Czechoslovakia and Yugoslavia were created for corresponding ethnic groups, while Austrian and Hungarian states were created for ethnic Germans and Magyars respectively (Austria still uses this border today). The Treaty of Versailles had forbidden Austria from joining Germany, however in 1938, German Chancellor Adolf Hitler (who was born in Austria) united the two nations as part of the German Third Reich, with overwhelming support by the people of Austria. In the next few years, Austria's population decreased slightly, as a result of the forced relocation of Jews and the outbreak of the Second World War. Due to the Austria-German union, separate records were not kept for Austrian and German deaths during the war, however most estimates put Austria's total at over 350,000 fatalities.

Post-war Austria

Following Germany's defeat, Austria was split into four separately administered sections, and then the Second Austrian Republic was established in 1955, declaring its permanent neutrality in foreign affairs. In the period after this Austria has enjoyed a period of continued prosperity with a high standard of living and reasonable economic growth. Population growth stagnated in the 80's with the legalization of abortion and improved access to contraception, but has grown steadily in the past three decades. Austria is consistently ranked among the top 20 richest countries in the world in terms of GDP per capita, and in 2018 it was ranked 20th in the world by the Human Development Index.

Much of Argentina's modern society and culture is rooted in the Spanish Empire's colonization of the region in the 16th century, along with the influx of European migration to the country around the turn of the twentieth century. There are records of human presence in the region dating back to the paleolithic period (3.3 million to 9,650 BCE) and the Incan Empire is known to have extended into the region before Columbus' arrival in the Americas in 1492; however most of this culture and civilization was wiped out by Europeans in the 1500s. During Spanish colonization, the majority of Argentina was a part of the Viceroyalty of the Río de la Plata (which also included territories in modern-day Chile, Bolivia, Paraguay and Uruguay) and was still economically bound to the Spanish crown. With a population of just 0.5 million in 1800, a combination of mass migration (particularly from Southern Europe) and high birth rates have helped Argentina's population grow above 45 million over the past two centuries.

Independence, Immigration and the Gold rush The age of enlightenment and revolutions in Europe inspired a longing in the region for independence, and Napoleon's invasion of Spain in 1808 was the catalyst for the Spanish Empire's downfall in the Americas, with Argentinian independence declared in 1816. The Spanish military was then defeated in mid 1800s, but for the majority of the next century there was little political or economic stability in the region, with several small-scale civil wars between the different Argentinian states. Starting with the government of Julio Argentino Roca in 1880, ten consecutive federal governments actively pursued a liberal economic policy which led to a massive wave of state-promoted European immigration; so much so that the number of migrants received by Argentina in that period was second only to the United States worldwide. This immigration led to the rejuvenation and reinvention of Argentinian society and economy to such an extent, that by 1908 the country had the seventh largest economy in the world. This in turn led to further immigration and higher standards of living. It is also worth noting that the Tierra del Fuego gold rush that started around 1883 and lasted to around 1906 also contributed greatly to immigration. Unfortunately, Argentina was unable to retain it's acquired economic might; it failed to develop industrially at the same speed as the rest of the world, and the Great Depression of 1929 set in motion an economic decline that contributed to much civil and political unrest.

The impact of Perón, and modern Argentina
The election of Juan Perón in 1946 proved to be a defining point in Argentina's history; Perón was a demagogue who imprisoned (and reportedly tortured) his rivals and critics, and whose isolationist policies and radical spending contributed to severe inflation. With the death of Perón's extremely popular wife, Eva Duarte, in 1952, his popularity declined and he was eventually exiled following a coup in 1955. Despite this exile, Perón returned in 1973 and re-assumed the presidency, until his death in 1974, where he was the succeeded by his third wife. Peron's political philosophy, known as "Peronism", is a mixture of right wing nationalist and left wing populist theories; although Peronism has developed greatly over time, its core belief system is the foundation of Argentina's largest party, the Justicialist Party (although they have become increasingly left wing since the Kirchner administrations).

With the expulsion of Perón in 1955, Argentina's trend of military coups and failed governments continued, and the country faced further economic instability. Despite all of this, medical advancements and improvements to quality of life across the globe helped Argentina's mortality rate to decline, and the population grew at a faster rate than ever before. In April 1982, Argentine forces invaded the British territory of the Falkland Islands, leading to a ten week war between the nations, that ended with Argentina's surrender in June. The war had a relatively small death toll, but contributed to riots in Buenos Aires, which helped to topple the military dictatorship and established the current democratic system. Following a severe recession that began in 2001, President Néstor Kirchner assumed office in 2003, and his wife took over from 2007 to 2015; during the Kirchner administrations, more than eleven million people were lifted out of poverty, and Argentina's economy grew in stature to become one of the Group of Twenty.

In 1800, the population of the islands which make up the territory of the Philippines had a population of approximately 1.89 million. The population of the archipelago would grow steadily throughout the 19th century, reaching almost 6.5 million people by 1900. However, the population would begin to rise much more rapidly following the country’s independence from the United States in 1946, as post-war economic aid from the United States and expansive modernization projects by the Philippine government would lead to a significant rise in standards of living and result in a post-war baby boom. This growth would remain steady well into the 21st century, and while the rate of population growth has fallen somewhat in recent years, the population of the Philippines is expected to continue its increase in the coming years, and in 2020, the Philippines is estimated to have a population of just under 110 million, which is almost twelve times larger than the Philippines' population in 1920.

In 1800, it is estimated that approximately 9.4 million people lived in the region of modern-day South Korea (and 13.8 million on the entire peninsula). The population of this region would remain fairly constant through much of the 19th century, but would begin to grow gradually starting in the mid-1800s, as the fall of the Joseon dynasty and pressure from the U.S. and Japan would end centuries of Korean isolationism. Following the opening of the country to foreign trade, the Korean peninsula would begin to modernize, and by the start of the 20th century, it would have a population of just over ten million. The Korean peninsula was then annexed by Japan in 1910, whose regime implemented industrialization and modernization policies that saw the population of South Korea rising from just under ten million in 1900, to over fifteen million by the start of the Second World War in 1939.

The Korean War Like most regions, the end of the Second World War coincided with a baby boom, that helped see South Korea's population grow by almost two million between 1945 and 1950. However, this boom would stop suddenly in the early 1950s, due to disruption caused by the Korean War. After WWII, the peninsula was split along the 38th parallel, with governments on both sides claiming to be the legitimate rulers of all Korea. Five years of tensions then culminated in North Korea's invasion of the South in June 1950, in the first major conflict of the Cold War. In September, the UN-backed South then repelled the Soviet- and Chinese-backed Northern army, and the frontlines would then fluctuate on either side of the 38th parallel throughout the next three years. The war came to an end in July, 1953, and had an estimated death toll of three million fatalities. The majority of fatalities were civilians on both sides, although the North suffered a disproportionate amount due to extensive bombing campaigns of the U.S. Unlike North Korea, the South's total population did not fall during the war.

Post-war South Korea Between the war's end and the late 1980s, the South's total population more than doubled. In these decades, South Korea was generally viewed as a nominal democracy under authoritarian and military leadership; it was not until 1988 when South Korea transitioned into a stable democracy, and grew its international presence. Much of South Korea's rapid socio-economic growth in the late 20th century was based on the West German model, and was greatly assisted by Japanese and U.S. investment. Today, South Korea is considered one of the world's wealthiest and most developed nations, ranking highly in terms of GDP, human development and life expectancy; it is home to some of the most valuable brands in the world, such as Samsung and Hyundai; and has a growing international cultural presence in music and cinema. In the past decades, South Korea's population growth has somewhat slowed, however it remains one of the most densely populated countries in the world, with total population of more than 51 million people.

In 1800, the population of the area of modern-day Pakistan was estimated to be just over 13 million. Population growth in the 19th century would be gradual in the region, rising to just 19 million at the turn of the century. In the early 1800s, the British Empire slowly consolidated power in the region, eventually controlling the region of Pakistan from the mid-19th century onwards, as part of the British Raj. From the 1930s on, the population's growth rate would increase as improvements in healthcare (particularly vaccination) and sanitation would lead to lower infant mortality rates and higher life expectancy. Independence In 1947, the Muslim-majority country of Pakistan gained independence from Britain, and split from the Hindu-majority country of India. In the next few years, upwards of ten million people migrated between the two nations, during a period that was blemished by widespread atrocities on both sides. Throughout this time, the region of Bangladesh was also a part Pakistan (as it also had a Muslim majority), known as East Pakistan; internal disputes between the two regions were persistent for over two decades, until 1971, when a short but bloody civil war resulted in Bangladesh's independence. Political disputes between Pakistan and India also created tension in the first few decades of independence, even boiling over into some relatively small-scale conflicts, although there was some economic progress and improvements in quality of life for Pakistan's citizens. The late 20th century was also characterized by several attempts to become democratic, but with intermittent periods of military rule. Between independence and the end of the century, Pakistan's population had grown more than four times in total. Pakistan today Since 2008, Pakistan has been a functioning democracy, with an emerging economy and increasing international prominence. Despite the emergence of a successful middle-class, this is prosperity is not reflected in all areas of the population as almost a quarter still live in poverty, and Pakistan ranks in the bottom 20% of countries according to the Human Development Index. In 2020, Pakistan is thought to have a total population of over 220 million people, making it the fifth-most populous country in the world.

While the East African region, including Kenya, is one of first regions believed to have modern humans inhabit it, population growth in the region remained slow to non-existent throughout the 19th century; in the past hundred years, however, Kenya’s population has seen an exponential increase in size, going from 2.65 million in 1920, to an estimated 53.77 million in 2020.

Along with this population growth, Kenya has seen rapid urbanization and industrialization, particularly in recent decades. The metropolitan area of Kenya’s capital, Nairobi, with an estimated population of 9.35 million in 2020, now contains on its own over three and a half times the population of the entire country just a century earlier.

In 1800, the population of Luxembourg was estimated to be 127,000, a figure which would rise steadily through the early 19 th century as the country would become an increasingly prominent city in the region. Luxembourg’s population would see its first major period of growth following the defeat of Napoleon in 1815, which would result in the previously-French occupied Luxembourg being granted formal autonomy in the subsequent Congress of Vienna. As a largely agrarian state at this time, the population of Luxembourg would see several periods of growth and decline throughout the remainder of the 20th century, as many residents emigrated abroad to countries such as the United States in search of work. Nevertheless, the population of Luxembourg would rise to over 235,000 by the turn of the century, as Dutch modernization and the removal of the city’s fortifications in the 1867 Treaty of London would allow for a greater expansion of the city proper.

The first half of the 20 th century would largely be a period of stagnation for the country, as the country would see large periods of stagnation in the 1910s and throughout the 1930s and 1940s, as occupation in both World Wars and the 1918 Spanish Flu epidemic) would see massive damage to the city in both human and economic terms. Luxembourg’s population would see significant growth in the country’s population, particularly so following the creation of the European Union in 1958 (Luxembourg was one of the six founding members of the union). Growth would accelerate even further following the 1980s, as increases in industrialization and accompanying economic growth would lead to an increasingly growing immigrant population from other EU nations in Luxembourg, which by 2015 would account for nearly half the citizens in Luxembourg. As a result of this growth, in 2020, Luxembourg is estimated to have a population of 626,000.