The world's population first reached one billion people in 1803, and reach eight billion in 2023, and will peak at almost 11 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 live 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 decade 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.
The region of present-day China has historically been the most populous region in the world; however, its population development has fluctuated throughout history. In 2022, China was overtaken as the most populous country in the world, and current projections suggest its population is heading for a rapid decline in the coming decades. Transitions of power lead to mortality The source suggests that conflict, and the diseases brought with it, were the major obstacles to population growth throughout most of the Common Era, particularly during transitions of power between various dynasties and rulers. It estimates that the total population fell by approximately 30 million people during the 14th century due to the impact of Mongol invasions, which inflicted heavy losses on the northern population through conflict, enslavement, food instability, and the introduction of bubonic plague. Between 1850 and 1870, the total population fell once more, by more than 50 million people, through further conflict, famine and disease; the most notable of these was the Taiping Rebellion, although the Miao an Panthay Rebellions, and the Dungan Revolt, also had large death tolls. The third plague pandemic also originated in Yunnan in 1855, which killed approximately two million people in China. 20th and 21st centuries There were additional conflicts at the turn of the 20th century, which had significant geopolitical consequences for China, but did not result in the same high levels of mortality seen previously. It was not until the overlapping Chinese Civil War (1927-1949) and Second World War (1937-1945) where the death tolls reached approximately 10 and 20 million respectively. Additionally, as China attempted to industrialize during the Great Leap Forward (1958-1962), economic and agricultural mismanagement resulted in the deaths of tens of millions (possibly as many as 55 million) in less than four years, during the Great Chinese Famine. This mortality is not observable on the given dataset, due to the rapidity of China's demographic transition over the entire period; this saw improvements in healthcare, sanitation, and infrastructure result in sweeping changes across the population. The early 2020s marked some significant milestones in China's demographics, where it was overtaken by India as the world's most populous country, and its population also went into decline. Current projections suggest that China is heading for a "demographic disaster", as its rapidly aging population is placing significant burdens on China's economy, government, and society. In stark contrast to the restrictive "one-child policy" of the past, the government has introduced a series of pro-fertility incentives for couples to have larger families, although the impact of these policies are yet to materialize. If these current projections come true, then China's population may be around half its current size by the end of the century.
In the past four centuries, the population of the United States has grown from a recorded 350 people around the Jamestown colony of Virginia in 1610, to an estimated 331 million people in 2020. The pre-colonization populations of the indigenous peoples of the Americas have proven difficult for historians to estimate, as their numbers decreased rapidly following the introduction of European diseases (namely smallpox, plague and influenza). Native Americans were also omitted from most censuses conducted before the twentieth century, therefore the actual population of what we now know as the United States would have been much higher than the official census data from before 1800, but it is unclear by how much. Population growth in the colonies throughout the eighteenth century has primarily been attributed to migration from the British Isles and the Transatlantic slave trade; however it is also difficult to assert the ethnic-makeup of the population in these years as accurate migration records were not kept until after the 1820s, at which point the importation of slaves had also been illegalized. Nineteenth century In the year 1800, it is estimated that the population across the present-day United States was around six million people, with the population in the 16 admitted states numbering at 5.3 million. Migration to the United States began to happen on a large scale in the mid-nineteenth century, with the first major waves coming from Ireland, Britain and Germany. In some aspects, this wave of mass migration balanced out the demographic impacts of the American Civil War, which was the deadliest war in U.S. history with approximately 620 thousand fatalities between 1861 and 1865. The civil war also resulted in the emancipation of around four million slaves across the south; many of whose ancestors would take part in the Great Northern Migration in the early 1900s, which saw around six million black Americans migrate away from the south in one of the largest demographic shifts in U.S. history. By the end of the nineteenth 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. Twentieth and twenty-first century The U.S. population has grown steadily throughout the past 120 years, reaching one hundred million in the 1910s, two hundred million in the 1960s, and three hundred million in 2007. In the past century, the U.S. established itself as a global superpower, with the world's largest economy (by nominal GDP) and most powerful military. Involvement in foreign wars has resulted in over 620,000 further U.S. fatalities since the Civil War, and migration fell drastically during the World Wars and Great Depression; however the population continuously grew in these years as the total fertility rate remained above two births per woman, and life expectancy increased (except during the Spanish Flu pandemic of 1918).
Since the Second World War, Latin America has replaced Europe as the most common point of origin for migrants, with Hispanic populations growing rapidly across the south and border states. Because of this, the proportion of non-Hispanic whites, which has been the most dominant ethnicity in the U.S. since records began, has dropped more rapidly in recent decades. Ethnic minorities also have a much higher birth rate than non-Hispanic whites, further contributing to this decline, and the share of non-Hispanic whites is expected to fall below fifty percent of the U.S. population by the mid-2000s. In 2020, the United States has the third-largest population in the world (after China and India), and the population is expected to reach four hundred million in the 2050s.
PERIOD: World total, circa 1920. SOURCE: [Statistics and reports of major countries].
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Japan Population Census: Age 30 to 34 Years data was reported at 7,290,878.000 Person in 2015. This records a decrease from the previous number of 8,341,497.000 Person for 2010. Japan Population Census: Age 30 to 34 Years data is updated yearly, averaging 7,681,689.000 Person from Dec 1920 (Median) to 2015, with 20 observations. The data reached an all-time high of 10,771,731.000 Person in 1980 and a record low of 3,609,450.000 Person in 1920. Japan Population Census: Age 30 to 34 Years data remains active status in CEIC and is reported by Statistical Bureau. The data is categorized under Global Database’s Japan – Table JP.G002: Population: Annual.
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Japan Population Census: Age 20 to 24 Years data was reported at 5,968,127.000 Person in 2015. This records a decrease from the previous number of 6,426,433.000 Person for 2010. Japan Population Census: Age 20 to 24 Years data is updated yearly, averaging 7,822,781.000 Person from Dec 1920 (Median) to 2015, with 20 observations. The data reached an all-time high of 10,727,636.000 Person in 1970 and a record low of 4,609,310.000 Person in 1920. Japan Population Census: Age 20 to 24 Years data remains active status in CEIC and is reported by Statistical Bureau. The data is categorized under Global Database’s Japan – Table JP.G002: Population: Annual.
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Japan Population Census: Female: Age 25 to 29 Years data was reported at 3,153,895.000 Person in 2015. This records a decrease from the previous number of 3,601,978.000 Person for 2010. Japan Population Census: Female: Age 25 to 29 Years data is updated yearly, averaging 3,867,713.500 Person from Dec 1920 (Median) to 2015, with 20 observations. The data reached an all-time high of 5,368,294.000 Person in 1975 and a record low of 1,915,944.000 Person in 1920. Japan Population Census: Female: Age 25 to 29 Years data remains active status in CEIC and is reported by Statistical Bureau. The data is categorized under Global Database’s Japan – Table JP.G002: Population: Annual.
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Japan Population Census: Age 50 to 54 Years data was reported at 7,930,296.000 Person in 2015. This records an increase from the previous number of 7,644,499.000 Person for 2010. Japan Population Census: Age 50 to 54 Years data is updated yearly, averaging 4,766,430.500 Person from Dec 1920 (Median) to 2015, with 20 observations. The data reached an all-time high of 10,441,990.000 Person in 2000 and a record low of 2,234,762.000 Person in 1920. Japan Population Census: Age 50 to 54 Years data remains active status in CEIC and is reported by Statistical Bureau. The data is categorized under Global Database’s Japan – Table JP.G002: Population: Annual.
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Japan Population Census: Male: Age 35 to 39 Years data was reported at 4,204,202.000 Person in 2015. This records a decrease from the previous number of 4,950,122.000 Person for 2010. Japan Population Census: Male: Age 35 to 39 Years data is updated yearly, averaging 3,859,640.500 Person from Dec 1920 (Median) to 2015, with 20 observations. The data reached an all-time high of 5,398,230.000 Person in 1985 and a record low of 1,707,771.000 Person in 1920. Japan Population Census: Male: Age 35 to 39 Years data remains active status in CEIC and is reported by Statistical Bureau. The data is categorized under Global Database’s Japan – Table JP.G002: Population: Annual.
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Ukraine Population Distribution: with Avg Income per Capita: Under 1920 UAH data was reported at 6.900 % in 2017. This records a decrease from the previous number of 18.400 % for 2016. Ukraine Population Distribution: with Avg Income per Capita: Under 1920 UAH data is updated yearly, averaging 53.150 % from Dec 2010 (Median) to 2017, with 8 observations. The data reached an all-time high of 78.100 % in 2010 and a record low of 6.900 % in 2017. Ukraine Population Distribution: with Avg Income per Capita: Under 1920 UAH data remains active status in CEIC and is reported by State Statistics Service of Ukraine. The data is categorized under Global Database’s Ukraine – Table UA.H009: Household Income and Expenditure: Annual.
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Japan Population Census: Age 70 to 74 Years data was reported at 7,695,811.000 Person in 2015. This records an increase from the previous number of 6,963,302.000 Person for 2010. Japan Population Census: Age 70 to 74 Years data is updated yearly, averaging 1,955,512.000 Person from Dec 1920 (Median) to 2015, with 20 observations. The data reached an all-time high of 7,695,811.000 Person in 2015 and a record low of 896,618.000 Person in 1920. Japan Population Census: Age 70 to 74 Years data remains active status in CEIC and is reported by Statistical Bureau. The data is categorized under Global Database’s Japan – Table JP.G002: Population: Annual.
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Japan Population Census: Age 15 to 64 Years data was reported at 76,288,736.000 Person in 2015. This records a decrease from the previous number of 81,031,800.000 Person for 2010. Japan Population Census: Age 15 to 64 Years data is updated yearly, averaging 69,781,671.000 Person from Dec 1920 (Median) to 2015, with 20 observations. The data reached an all-time high of 87,164,721.000 Person in 1995 and a record low of 32,605,495.000 Person in 1920. Japan Population Census: Age 15 to 64 Years data remains active status in CEIC and is reported by Statistical Bureau. The data is categorized under Global Database’s Japan – Table JP.G002: Population: Annual.
In 1800, the region of Germany was not a single, unified nation, but a collection of decentralized, independent states, bound together as part of the Holy Roman Empire. This empire was dissolved, however, in 1806, during the Revolutionary and Napoleonic eras in Europe, and the German Confederation was established in 1815. Napoleonic reforms led to the abolition of serfdom, extension of voting rights to property-owners, and an overall increase in living standards. The population grew throughout the remainder of the century, as improvements in sanitation and medicine (namely, mandatory vaccination policies) saw child mortality rates fall in later decades. As Germany industrialized and the economy grew, so too did the argument for nationhood; calls for pan-Germanism (the unification of all German-speaking lands) grew more popular among the lower classes in the mid-1800s, especially following the revolutions of 1948-49. In contrast, industrialization and poor harvests also saw high unemployment in rural regions, which led to waves of mass migration, particularly to the U.S.. In 1886, the Austro-Prussian War united northern Germany under a new Confederation, while the remaining German states (excluding Austria and Switzerland) joined following the Franco-Prussian War in 1871; this established the German Empire, under the Prussian leadership of Emperor Wilhelm I and Chancellor Otto von Bismarck. 1871 to 1945 - Unification to the Second World War The first decades of unification saw Germany rise to become one of Europe's strongest and most advanced nations, and challenge other world powers on an international scale, establishing colonies in Africa and the Pacific. These endeavors were cut short, however, when the Austro-Hungarian heir apparent was assassinated in Sarajevo; Germany promised a "blank check" of support for Austria's retaliation, who subsequently declared war on Serbia and set the First World War in motion. Viewed as the strongest of the Central Powers, Germany mobilized over 11 million men throughout the war, and its army fought in all theaters. As the war progressed, both the military and civilian populations grew increasingly weakened due to malnutrition, as Germany's resources became stretched. By the war's end in 1918, Germany suffered over 2 million civilian and military deaths due to conflict, and several hundred thousand more during the accompanying influenza pandemic. Mass displacement and the restructuring of Europe's borders through the Treaty of Versailles saw the population drop by several million more.
Reparations and economic mismanagement also financially crippled Germany and led to bitter indignation among many Germans in the interwar period; something that was exploited by Adolf Hitler on his rise to power. Reckless printing of money caused hyperinflation in 1923, when the currency became so worthless that basic items were priced at trillions of Marks; the introduction of the Rentenmark then stabilized the economy before the Great Depression of 1929 sent it back into dramatic decline. When Hitler became Chancellor of Germany in 1933, the Nazi government disregarded the Treaty of Versailles' restrictions and Germany rose once more to become an emerging superpower. Hitler's desire for territorial expansion into eastern Europe and the creation of an ethnically-homogenous German empire then led to the invasion of Poland in 1939, which is considered the beginning of the Second World War in Europe. Again, almost every aspect of German life contributed to the war effort, and more than 13 million men were mobilized. After six years of war, and over seven million German deaths, the Axis powers were defeated and Germany was divided into four zones administered by France, the Soviet Union, the UK, and the U.S.. Mass displacement, shifting borders, and the relocation of peoples based on ethnicity also greatly affected the population during this time. 1945 to 2020 - Partition and Reunification In the late 1940s, cold war tensions led to two distinct states emerging in Germany; the Soviet-controlled east became the communist German Democratic Republic (DDR), and the three western zones merged to form the democratic Federal Republic of Germany. Additionally, Berlin was split in a similar fashion, although its location deep inside DDR territory created series of problems and opportunities for the those on either side. Life quickly changed depending on which side of the border one lived. Within a decade, rapid economic recovery saw West Germany become western Europe's strongest economy and a key international player. In the east, living standards were much lower, although unemployment was almost non-existent; internationally, East Germany was the strongest economy in the Eastern Bloc (after the USSR), though it eventually fell behind the West by the 1970s. The restriction of movement between the two states also led to labor shortages in the West, and an influx of migrants from...
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Japan Population Census: Age 75 to 79 Years data was reported at 6,276,856.000 Person in 2015. This records an increase from the previous number of 5,941,013.000 Person for 2010. Japan Population Census: Age 75 to 79 Years data is updated yearly, averaging 1,193,284.000 Person from Dec 1920 (Median) to 2015, with 20 observations. The data reached an all-time high of 6,276,856.000 Person in 2015 and a record low of 482,012.000 Person in 1920. Japan Population Census: Age 75 to 79 Years data remains active status in CEIC and is reported by Statistical Bureau. The data is categorized under Global Database’s Japan – Table JP.G002: Population: Annual.
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Japan Population Census: Age 25 to 29 Years data was reported at 6,409,612.000 Person in 2015. This records a decrease from the previous number of 7,293,701.000 Person for 2010. Japan Population Census: Age 25 to 29 Years data is updated yearly, averaging 7,743,240.500 Person from Dec 1920 (Median) to 2015, with 20 observations. The data reached an all-time high of 10,794,583.000 Person in 1975 and a record low of 3,923,949.000 Person in 1920. Japan Population Census: Age 25 to 29 Years data remains active status in CEIC and is reported by Statistical Bureau. The data is categorized under Global Database’s Japan – Table JP.G002: Population: Annual.
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Chart and table of Kuwait population from 1950 to 2025. United Nations projections are also included through the year 2100.
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Japan Population Census: Male: Age 80 to 84 Years data was reported at 1,994,326.000 Person in 2015. This records an increase from the previous number of 1,692,584.000 Person for 2010. Japan Population Census: Male: Age 80 to 84 Years data is updated yearly, averaging 216,141.000 Person from Dec 1920 (Median) to 2015, with 20 observations. The data reached an all-time high of 1,994,326.000 Person in 2015 and a record low of 65,473.000 Person in 1920. Japan Population Census: Male: Age 80 to 84 Years data remains active status in CEIC and is reported by Statistical Bureau. The data is categorized under Global Database’s Japan – Table JP.G002: Population: Annual.
At the beginning of the 19th century, the area of modern-day Italy, at the time a collection of various states and kingdoms, was estimated to have a population of nineteen million, a figure which would grow steadily throughout the century, and by the establishment of the Kingdom of Italy in 1861, the population would rise to just over 26 million.
Italy’s population would see its first major disruption during the First World War, as Italy would join the Allied Forces in their fight against Austria-Hungary and Germany. In the First World War, Italy’s population would largely stagnate at 36 million, only climbing again following the end of the war in 1920. While Italy would also play a prominent role in the Second World War, as the National Fascist Party-led country would fight alongside Germany against the Allies, Italian fatalities from the war would not represent a significant percentage of Italy’s population compared to other European countries in the conflict. As a result, Italy would exit the Second World War with a population of just over 45 million.
From this point onwards the Italian economy started to recover from the war, and eventually boomed, leading to increased employment and standards of living, which facilitated steady population growth until the mid-1980s, when falling fertility and birth rates would cause growth to largely cease. From this point onward, the Italian population would remain at just over 57 million, until the 2000s when it began growing again due to an influx of migrants, peaking in 2017 at just over 60 million people. In the late 2010s, however, the Italian population began declining again, as immigration slowed and the economy weakened. As a result, in 2020, Italy is estimated to have fallen to a population of 59 million.
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Japan Population Census: Female: Age 65 Years & Over data was reported at 18,979,972.000 Person in 2015. This records an increase from the previous number of 16,775,273.000 Person for 2010. Japan Population Census: Female: Age 65 Years & Over data is updated yearly, averaging 3,820,838.000 Person from Dec 1920 (Median) to 2015, with 20 observations. The data reached an all-time high of 18,979,972.000 Person in 2015 and a record low of 1,638,915.000 Person in 1920. Japan Population Census: Female: Age 65 Years & Over data remains active status in CEIC and is reported by Statistical Bureau. The data is categorized under Global Database’s Japan – Table JP.G002: Population: Annual.
Climate variations on seasonal-to-decadal (S2D) timescales can have enormous social, economic, and environmental impacts, making skillful predictions on these time scales an invaluable tool for policymakers and stakeholders. Such variations modulate the likelihood and intensity of extreme weather events including, tropical cyclones (TCs), heat waves, winter storms, atmospheric rivers (ARs), and floods, which have all been associated with (1) increases in human morbidity and mortality rates; (2) severe impacts on agriculture, energy use, and industrial activity; and (3) economic costs in the billions of dollars. Changes in prevailing climate patterns are also responsible for prolonged droughts, which can have profoundly negative effects on large segments of the world population. Enhancing our foreknowledge of climate variability on S2D time scales and understanding its influence on extreme weather events could help mitigate negative impacts on human and biological populations, making climate predictions an exceptionally important climate and social science frontier.
Over the past six years, our research team consisting of scientists at Texas A and M University (TAMU) and the U.S. National Science Foundation National Center for Atmospheric Research (NSF NCAR) has made major breakthroughs in advancing high-resolution global climate modeling and prediction. We have completed an unprecedented 10-member ensemble of Community Earth System Model (CESM) historical and future climate simulations at a TC-permitting and ocean-eddy-rich resolution (hereafter simply referred to as CESM-HR). This CESM-HR ensemble was completed as part of our NSF-funded project entitled "Understanding the Role of MESoscale Atmosphere-Ocean Interactions in Seasonal-to-Decadal CLImate Prediction (MESACLIP)". This ensemble is particularly timely, following the April 2023 report entitled "Extreme Weather Risk in a Changing Climate: Enhancing Prediction and Protecting Communities" from the U.S. President's Council of Advisors on Science and Technology (PCAST). Indeed, this report made several recommendations on how climate science can support the provision of information about future risks from extreme weather and highlight the urgent need for high-resolution simulations to improve predictions of extreme weather events and guide risk management strategies. More specifically, the report recognized that high-resolution simulations, in the range of 10-25km horizontal resolution, would capture extreme events more accurately than typical low-resolution (approximately 100km) climate projections, and it goes on to recommend "a focused federal effort to provide estimates of the risk that a weather event of a given severity will occur in any location and year between now and mid-century". Our 10-member CESM-HR ensemble is able to meet some of the key aspects of this PCAST report.
The CESM-HR configuration is based on an earlier CESM version, CESM1.3, with many additional modifications and improvements. CESM-HR uses a 0.25 degree grid in the atmosphere and land components and a 0.1 degree grid in the ocean and sea-ice components. The primary reason for using an older model version, instead of the latest CESM2, is that CESM2 does not support a high-resolution version per the decision by the CESM Scientific Steering Committee. The component models within CESM1.3 are the Community Atmosphere Model version 5 (CAM5; Neale et al. 2012), the Parallel Ocean Program version 2 (POP2; Danabasoglu et al. 2012; Smith et al. 2010), the Community Ice Code version 4 (CICE4; Hunke and Lipscomb, 2008), and the Community Land Model version 4 (CLM4; Lawrence et al. 2011).
The CESM-HR ensemble experimental design follows a similar approach as the CESM LENS1 large ensemble. We started with a 500-year preindustrial control (PI-CTRL) simulation forced by a perpetual climate forcing that corresponds to the year 1850 conditions. The first ensemble member is branched at year 250 of the PI-CTRL simulation and then integrated forward from year 1850 to 2100 (Figure 1 [https://rda.ucar.edu/OS/web/datasets/d651007/docs/Figure1_RDA_d651007.png]). Ensemble members 2-10 are subsequently started from the year 1920 of ensemble member 1 and integrated forward to 2100 (Figure 1 [https://rda.ucar.edu/OS/web/datasets/d651007/docs/Figure1_RDA_d651007.png]). Spread in the ensemble is generated by applying round-off level perturbations in the atmospheric potential temperature initial conditions for members 2-10. All 10 members use the same specified external climate forcing. Following the CMIP5 protocol for the Coupled Model Intercomparison Project phase 5 (CMIP5) experiments, historical forcing is used from 1920 to 2005 followed by the representative concentration pathway 8.5 (RCP 8.5) forcing from 2006 to 2100. RCP 8.5 is a high-emissions scenario and is frequently referred to as the "business as usual" scenario. It refers to the concentration of carbon that delivers global warming at an average of 8.5 W/m^2 across the planet by 2100. All 10 members produce a warming of approximately 4.5K at the end of 2100 in response to the applied historical and RCP 8.5 external forcing (Figure 1 [https://rda.ucar.edu/OS/web/datasets/d651007/docs/Figure1_RDA_d651007.png]). The warming produced by CESM-HR is consistent with the warming from the standard low-resolution (approximately 1 degree) version of the model. The rate of warming simulated by CESM-HR over the observed period agrees very well with the observed rate of warming derived from the Goddard Institute for Space Studies (GISS) Surface Temperature Analysis (Figure 1 [https://rda.ucar.edu/OS/web/datasets/d651007/docs/Figure1_RDA_d651007.png]).
Citation: The two papers linked below are the most appropriate references for the CESM-HR ensemble. To cite the dataset, use Chang et al. (2025). We ask that you also cite the dataset itself using the reference Castruccio et al [https://rda.ucar.edu/datasets/d651007/citation/]. (2024) in any documents or publications using these data. Chang et al. (2020) describes the initial CESM-HR simulations, including the 500-year pre- industrial control simulation and the first 250-year historical and future climate simulation from 1850 to 2100. We would also appreciate receiving a copy of the relevant publications. This will help us to justify keeping the data freely available online in the future. Thank you!
The world's population first reached one billion people in 1803, and reach eight billion in 2023, and will peak at almost 11 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 live 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 decade 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.