A common question that people have asked throughout all ages ask is about the history of the world population. Specifically, how many people have ever lived and when? Scientific evidence suggests that the world population has changed drastically throughout history and at different periods of the development of earth. Once growing slowly and sustainably, over the last century population growth has been exponential and giving rise to ever greater levels of concern.
Historical Growth of Human Population
Researchers believe that the human population began around 3 million years ago, but as hunter-gatherers, the population size remained small. In fact, around 130,000 years Before the Common Era (BCE), the number of humans on earth was only around 200,000 and largely concentrated on what is now the African continent. This is also when humans began migrating to other areas of Africa from the eastern side due a changing climate that brought on droughts. The lack of rain sent early humans in search of water and thereby spreading the population. In the beginning, there were 3 human species. Fast-forward to the year 10,000 BCE, the world population was significantly higher than its beginning numbers. During these years, the earth housed around 3 million people. Over the span of 100,000 years, 2 human species became extinct largely due to an extreme change in climate. This climate change was prompted by a super-volcanic eruption that led to a years-long winter. First, the Neanderthals died out and this event was followed by the Homo floresiensis. These extinctions left Homo sapiens, modern day humans, as the only human species on earth. As population size began to grow and the winter seemed like it would never end, humans spread out once again across the globe. It is believed that they first reached the Asian continent and 30,000 years later, Australia. The great migration continued until humans also found their way to Europe and then the Americas. It is after all of this change, that humans discovered agriculture.
The First Agricultural Revolution
By the year 6,500 BCE, the population reached 10 million and this was largely the cause of the first Agricultural Revolution. This is the era in which humans learned to control crops and animals. They gradually left behind the nomadic, hunter-gatherer lifestyle and began to settle in villages and other permanent settlements. This corresponds to a warming period that occurred right after having experienced an ice age. The first recorded agricultural revolution took place in the Fertile Crescent located in the Middle East. Today, anthropologists have also determined that a simultaneous agricultural revolution was happening throughout Asia and South America. The next few thousand years brought on the domestication of cows, sheep, horses, and chickens, and the cultivation of wheat, corn, rice, potatoes, and bananas. Wine and cheese making, decorations for aesthetic value, and brick buildings began to make the scene. And with this increased security and comfort came another growth in the population. With more food and less danger from constantly moving, the human population began to grow at a much faster rate than previously. In 2,000 BCE, the number of humans reached 50 million and quadrupled by the time of "Year 0" (0 BCE/0 CE). Had this not revolution not taken place, continued technological advances would not have been possible.
The Industrial Revolution
Despite smallpox and the bubonic plague, humans reached 1 billion by 1804. How did this happen? The coming of the Roman Empire at the dawn of the Common Era allowed for political and economic organization that further supported human growth and chance of survival. Human labor during this time was carried out in order to benefit the few or the elite (those that would have access to the fruits of this labor) rather than for self-sustainability. This continued through the Industrial Revolution and as some would argue, is happening today as well. Occurring between 1760 and 1820, the Industrial Revolution changed the way humans work. It shifted production methods from being done by hand to using machines. People began harnessing the power of water and using it to create steam energy which was used to power machinery. Factories blossomed and largely existed to produce textiles, the dominant industry. This is the moment in history that is responsible for sustained population growth. The standard of living increased during the Industrial Revolution in ways never before seen, household incomes grew, and transportation increased which lowered the cost of food and clothing and household goods. This was the basis for modern day capitalism. Although, this seemingly bright moment in human development did not come without its dark spots as well. The increased standard of living did not reach everybody equally, and the working class and rural populations still suffered from hunger and unclean living situation. Disease was rampant in urban centers and tuberculosis, typhoid, and cholera spread.
Improvements in Public Health and Medicine
The world population reached 2 billion in 1927 and this increase was partly due to improved public health standards. The spread of disease seen during the Industrial Revolution sparked this public health movement and it was the cholera pandemic specifically that played a key role. It brought about a focus on breathing clean, circulated air and placing cemeteries away from neighborhoods. The installation of sewage and drainage systems came after the signing of the Public Health Act in 1848. This improved the sanitary conditions of towns. At the same time, the use of vaccinations grew which led to the eradication of smallpox. By 1851, vaccinations were mandatory and by 1870, the government had established a registration system complete with vaccine officers. Other public health acts enforced proper garbage collection and disposal, public water services, and mosquito prevention. It also became mandatory to report infectious diseases so that proper quarantining measures could take place. The population continued to grow exponentially. The world saw 3 billion by 1959 and 5 billion by 1987. Today, human population has surpassed 7 billion.
Increased Strain on Resources
The size of the earth doesn’t change to support human population. The environment available to people has a finite supply of resources including food, space, and energy. Human growth has already left its mark on these resources. In the mid-1990’s, over 80% of the land on earth had been affected by human presence. Animal extinction rates are 48 times higher than what would occur naturally and 70% of the world’s freshwater is used for irrigation purposes. Today, the world faces food and water shortages at levels not previously experienced. The two go hand in hand, food cannot be produced without water. There are already areas in the world without reliable access to water and 700 million people suffer from scarcity. Food and water insecurity disproportionately affects the disadvantaged and those living in poverty. This presents a challenge to governments everywhere as the need exists for them to create policy to address these issues and ensure equal access to resources.
The majority of future population growth is expected to occur throughout less developed nations like those in Asia, Latin America, and Africa. This is expected because the standard of living is expected to improve within these regions. Estimates claim the world population will grow to 9 billion by 2050. This huge number brings up the question of the earth’s carrying capacity. The carrying capacity is the ability of earth to meet the demand of natural resources by a particular species. One thing is certain, the earth is near the end of its capacity and soon will be unable to sustain human demand. Unrestrained population growth cannot continue if the human species is to survive.