The Growth of Human Population in the Last Years

Over the past 1,000 years the human population has been relatively stable, besides, the downward trend due to illness (black death) and in the recent few hundred years there has been an increase in population growth. The rate that populations grow is another factor that influences Earth's resources. Earth experienced a period of its fastest growth between 1975-2011 by taking 12 years to increase by one billion (Roser & Ortiz-Ospina, 2017). According to the UN the population growth has reached its peak and should continue to decline in the coming decade (Roser & Ortiz-Ospina, 2017). The study of human population growth is important because it helps us understand what we need to do now to support the future population size. By studying the past demographers are able to predict how growth affects the near future.

Human population growth is based off of numerous factors such as changes to population size, fertility, life expectancy, age structure, and migration. Demographers study each of these to help understand the roles they play in human population size.

Population size changes are based off factors that increase and decrease the size. Immigration and births are inputs that increase the population size, while emigration and deaths are outputs that decrease the population size (Friedland & Relyea, 2016). Demographers monitor these inputs and outputs to equate the changes to population size. When the population is greater than emigration and deaths there is a positive growth rate, and when emigration and deaths are greater than immigration and births there is a negative growth rate.

Fertility rates vary between developed and developing countries. Developed countries like the U.S. experience slower population growth in comparison to developing countries like China and India. Demographers look to the total fertility rate (TFR) to determine the expected average number of children a woman will bear throughout her childbearing years. Looking at this information can help to determine the role births play in population growth. Looking further into calculating the changes in population size demographers look at the replacement- level fertility to evaluate how many births it would take to offset the deaths to keep a stable population size. Due to the mortality rates being higher in developing countries we see a replacement level higher than 2.1, which is the typical replacement level in developed countries (Friedland & Relyea, 2016).

Factors that influence life expectancy are infant and child mortality, and aging and disease. Access to health care, nutrition, and exposure to pollutants impact the infant and child mortality rate. These factors contribute to the varying rates around the world. A country that has available healthcare, clean water, nutrition, and a low level of pollutants typically have a high life expectancy and a low infant mortality rate. But a country that has an immense amount of pollution, non-sanitary drinking water, and poor lack of resources for food would typically see a low life expectancy and a high infant mortality rate (Friedland & Relyea, 2016).

Aging and disease affect life expectancy is different ways. Some countries have a higher elder population therefore experience a higher death rate, compared to populations dominated by youth. According to Friedland & Relyea disease is an important factor in regulating the human population. Diseases like AIDS and HIV have decreased the life expectancy in countries where the diseases have increased. The affects of disease vary depending on the development of the country in modern time. In countries like the U.S. treatments are available to extend the livelihood of a person with disease, while in countries in Africa do not have the resources to treat disease and experience a higher death rate as well as a lower life expectancy. As nations healthcare and availability change and increase we can see improvements of life expectancy.

Humans in developed countries are experiencing increasing life expectancies. Countries like the United States, Australia, Canada, and Western Europe have a life expectancy of 75 and above (Friedland & Relyea, 2016). Low child and infant mortality, more available health care, new technological advancements, sufficient food and healthier lifestyles contribute to the increasing life expectancies (Brown, 2015).

Age structure helps to determine the rate the population grows. When you have a population with more old people than young people you can reason that the population will have a slower growth rate. A population where there are more young people than old people you can reason that the population will have a faster growth rate.

Migration works differently in the fact that people are moving from one place to another and not lessening the population. It is still important to study to figure out why people are moving, is it do to natural disasters, disease, or for a better life? When you take this information into account it can help make sense of the needs of different countries. Are the places people migrate to able to support the increase population?

Can the Earth continue to support the population growth or is there a limit to available resources? Earth's carrying capacity is a debatable theory, which scientists disagree upon. Some scientists believe that the human population will outgrow or in fact have outgrown the supply of resources needed to survive. Contradictory to that some scientists believe the supply will adjust to support the growing population therefore disagreeing that Earth has a fixed carrying capacity. In the 11th century Earth's population was beginning to increase, by the year 1346-1351 the plague had hit and decreased the population with the lowest point around 1400. Beginning in the 19th century during the Industrial Revolution the population exceeded 1 billion for the first time (Van Bavel, 2013). The carrying capacity has increased over time to meet the demands of the population. The industrial revolution had only artificially increased the carrying capacity because the burning of fossil fuels does not indefinitely support sustainability (Michel Serres Institute for Resources and Public Goods, 2012). To sustain the human populations carrying capacity focus needs to be on family planning strategies as well as management of natural resources. It is not enough to just consider density when adjusting for carrying capacity because different demographics impact the environment differently.

There are effective ways in which we can slow the human population growth. While family planning can make an impact it is not sufficient enough to use on its own. In 1960 it was estimated that family planning had reduced total fertility rate by 55% (Miller & Spoolman, 2015). However, in developing countries there is a lack of access to the family planning, even for women who want the education. It is in developing countries we see an increase in the total fertility rate while developed countries have nearly ceased. Other contributors like reducing poverty and elevating the status of women are important for reducing the growth effectively. In countries where women are educated there tends to be a lower fertility rate, even when women do have children they tend to have less and later in life, as well as being able to support them economically (Fitzgerald-Reading, 2011). In order to effectively slow population the combined efforts of education, family planning, and reduction of poverty need to be accessible to men and women of developed and developing countries.

Population growth has substantial effects on the Earth's environment. Developed and developing countries have different effects on the environment. Barry Commoner, Paul Ehrlich and John Holdren created the equation Impact= Population X Affluence X Technology. Population, affluence and technology combine to influence the environmental impact (Friedland & Relyea, 2016).

An area with a high population is going to impact the environment more than an area with low population. When a population is higher there are more uses of resources, as well as more outputs of pollutants. Affluence is not evaluated the same as population, a small family in a developed country can have a greater impact than a large family in a developing country. When a person/family has more lavish possessions such as cars, homes, pools, boats, etc., their impact is greater than a person/family who does not own a vehicle, uses shared transportation, rides a bike, or rents an apartment without a lawn. Technology can both impact the environment positively and negatively. Technological advancements such as electric cars, solar panels, and wind-powered energy work to lessen the environment impact that has been damaged by destructive technology like SUVS and truck emissions, chlorofluorocarbons, and plastic.

Population impact reaches local, global and urban environments. Developing countries experience more local impacts in comparison to developed countries. Developing countries do not have the economic means to import food. This leads developing countries to take actions that deforest land in order to have the space to grow their food. When a country clears land for agriculture it can lead to adverse climate effects like erosion, soil degradation and habitat loss (Friedland & Relyea, 2016).

Global impacts are made when affluent countries consume resources that need to be imported such as oil, and food. There are also global impacts due to agriculture, when land is deforested or turned into agriculture, it reduces the plants in which reduces the amount of carbon dioxide extracted out of the environment, increasing the greenhouse gases into the atmosphere (Friedland & Relyea, 2016). Developed countries do not always contribute to greater global impact in a negative way, countries who have developed technology to reduce their environmental impact diminish some negative effects of waste by using sewage treatment and household solid waste.

In urban environments the population accounts for less but consumes more resources. Developed countries urban environments account for less environmental impact compared to developing countries impact. Developed countries can use technology to offset the population impact with development of public transportation, sewer lines, energy efficient buildings, and nearby services. In developing countries the affluent experience the same luxuries as those in developed countries, but the less wealthy do not have access to those same luxuries. Instead the poor contribute greater to the environmental impact because of their lack of resources.

The level of the nations wealth impacts the environment. A country with higher affluence is able to afford to burn more fossil fuels, but how they burn them depends on their advancement. The more money a country has the better resources they can afford, they are able to burn fossil fuels more efficiently than a less affluent country, as well as enforce policies that improve the environment. Higher affluence correlates with lower birth rates, when a women is educated they tend to wait to have children and once they do they educate their children as well which creates a trickle down affect that lowers the birth rates.

Increased population growth has an affect on food and water supply. How do we feed an increasing population size without harming the environment more? How do we supply the growing population with drinkable water, as well as enough water to supply agriculture?

National Geographic has constructed a five-step plan to feed the growing population while maintaining environmental friendly practices. Step one would be to freeze agriculture's footprint, this simple means that there cannot be any more deforestation allowed. We have to seek alternatives to supply food. The second step is to grow more on the farms we already have, by using the land already designated for farms we are able to prevent deforestation. Step three is to use resources more efficiently, produce higher yields, customize fertilizer to what you need, as well as switch to organic farming, where you use natural resources to create higher yields. Fourth step is shifting diets, we need to consume more of the crops we yield, and reduce the amount of meat we intake. Step five is to reduce waste; this is such an important step (National Geographic, 2018). Due to strict policies in the U.S. it is hard for companies and food retailers to better distribute left over food. The U.S. alone wastes between 30-40% of its food supply (USDA, 2018). The combination of all the steps constructed can make a difference in supporting the Earth's carrying capacity.

Alternatively, if the five-steps cannot be accomplished agricultural land needs to improve the yield in both developed and developing nations. Wealthy nations are able to generate alternative food supplies such as genetically modified foods. This unfortunately this is only beneficial to the countries that have the financial means to produce the GMO crops. By using genetically modified foods we can create crops to resist natures infortunes, like bugs and inclement weather. There are downsides to this method however, the technology is relatively new and we do not understand all the potential risks. As well as it is possible that the modified foods will create super bugs and weeds that will evolve to survive with the GMOs.

Fresh water is a finite source, and only a very small percentage (0.3%) of it is readily available for human use (Mullen, 2012). States are already experiencing droughts and water restrictions. The problem is only expected to increase in the future years. Initiatives need to be taken locally and globally for the future population to be supported. The problem with addressing water usage in households is that measures need to be taken voluntarily, such as fixing household leaks, shorter showers, turning off the faucet while brushing teeth/washing face, low flush toilets, energy efficient washing machines, and low flow shower heads. These small individual tasks contribute to a greater reduction when a large number of the population follows the suggestions. By using National Geographic's fourth step of shifting our diet we could reduce the amount of water use. Beef production alone uses almost 100 times more water than most vegetables (Hill, 2010). Increasing the efficiency of water usage in agriculture by improving and updating irrigation systems is another important conservation initiative. It is also important to protect the water we have that is available for use. We need to reduce the water pollution by reducing pollutants running off, ban waste dumping in waters, reduce the use of fertilizers and pesticides and prevent marine plastic debris that also pollutes the water by breaking down into micro plastics that are nearly impossible to remove.

In order for the Earth to support the population size of the future we need to achieve environmental sustainability. Developed and developing countries need to work together to efficiently use Earth's natural resources in moderation. Overall education is the key to the future. By studying the past 1000 years of population growth and human usage we have learned what worked for nations and what does not. We need to effectively apply this information in order to not abuse Earth's capacity, in combination with that we need to continue to be innovative in ways that support our population growth. By educating men and women we can reduce fertility rates, increase environmentally friendly practices, and contribute to a high gross domestic product. The solution to human population growth is not a simple one step process, but rather multiple steps that need to be improved as the population size and innovations continue to change.

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