According to the World Population Meter (WorldoMeters, 2017) the current world population is about to become 7.6 billion. At a growth rate of around 200,000 people per day (due to a rising birth rate and decreasing death rate), the world population is rapidly growing. Although population growth is dominated by a few countries, China and India being the main two (with a billion more people in each country than the United States which is third), the challenges of population growth are felt all over the globe (DESA, 2017). The main challenges are on climate change, which thus impacts water scarcity, which then follows a challenge in food security. Due to the growing population, more people are living in cities which creates urbanisation, which goes hand in hand with the issue of deforestation. In this essay I will go into detail about each challenge and explain how they are all linked to the issue of global population growth.
Urbanisation and the consequent deforestation are two major challenges posed by global population growth. Urbanisation is the ‘shift in a population from one that is dispersed across small rural settlements in which agriculture is the dominant economic activity towards one where the population is concentrated in large, dense urban settlements characterised by industrial and service activities’ (Montgomery et al., 2004). Economic development causes people to be drawn to cities that have more varied opportunities for education and employment, but due to the rising population, this is occurring more frequently. The cycle then continues, as due to the density of people and businesses in cities that share knowledge and information, new enterprises and technological innovation is made, and thus more and more people are drawn to these information hubs. (UN Population Division, 2015) This is shown by the fact that approximately 80% of global gross domestic product (GDP) is generated in cities (Grübler and Fisk, 2013). According to the Population Division, United Nations, since 2007, more people live in urban areas than in rural areas (UN Population Division, 2015). This is expected to continue, so that by 2050, the world will be one-third rural and two-thirds urban (UN Population Division, 2015).
The problems of this can be seen in the case of China, as resource scarcity and environmental degradation are big problems that they face, as urbanisation is dependent on a steady supply of natural resources, for example fresh water and fuel, and these resources are put under pressure due to the population growth (Chen, 2007). China is feeding 22% of the global population on less than 9% of the world’s cultivated land, so there is an issue as the demand is not being met (Chen, 2007). Furthermore, soil availability for agricultural production has worsened due to the rapid population growth and accelerated urbanisation, which then means that less crops can be grown in China, and more have to be imported in. (Zhang et al., 2004). With a population of over a billion people, China feels the brunt of the problems, for example 78% of all streams crossing urbanised regions have been so polluted that the water is no longer available for drinking (Chen, 2007). This shows that population growth is an issue because with more areas becoming urbanised, and more people moving to urban areas, there puts a pressure on the demand of resources, which cannot be met in developing countries. Sustainable urban development becomes almost impossible to reach due to the rapid urbanisation crossed with the lack of environmental strategies (Brebbia et al., 2017).
Urbanisation often is allowed to take place due to the deforestation of lands to make room for cities to be built. A study on the demographic and economic factors associated with forest loss found that urban growth shows a positive association of forest loss (DeFries et al., 2010). The analysis suggests that the high rates of forest loss between 2000-2005 are associated with the demands for agricultural products in urban and international locations (DeFries et al., 2010). This regression tree is derived from ten demographic, agricultural and economic variables for countries in the study. It confirms the role of agricultural exports and urban growth as the main drivers of forest loss between 2000-2005. On the diagram, the hexagons are terminal nodes, with mean forest loss & deviance in brackets and the thickness of the lines represents the relative amount of remaining humid tropical forest in each node (DeFries et al., 2010). This is due to population growth because as the number of people on the Earth grows, so does the demand for agricultural products such as food, which I will discuss later.
Deforestation also causes issues with water security because forests provide more stable patterns of river runoff due to greater catchment. With less forest cover, there is accelerated runoff and lost storage, resulting in a higher occurrence of flooding in wet seasons, and a greater chance of dried-up rivers in dry seasons (United Nations Population Information Network, 1994). Although this report is old, it is not outdated, and the concepts are still relevant today, as is seen in South America with the Amazon’s deforestation threatening South America’s water security. In 2013 it was reported that deforestation in Amazonia has increased by almost a third in a year, and the countries that this affects the most are the five countries that share the Amazon River: Bolivia, Brazil, Colombia, Ecuador and Peru (Brown, 2013). For all of them, the forest area occupies more than 40% of their territory and they all face threats to their water supply, as well as energy production, food and health (Brown, 2013). Furthermore, the Amazonia Security Agenda has found that because of over-exploitation of the region, rainfall is expected to fall by 20% over the heavily populated La Plata basin, which covers parts of Argentina, Brazil, Bolivia, Paraguay and Uruguay (Brown, 2013). This is a problem because the prosperity of the region is based on the abundance of water, and with the combination of industrial and agricultural pollution, as well as droughts in the region, the five countries are left vulnerable. This is a result of a growing population because the immediate water needs of these countries outweighs the need to be sustainable.
Climate change is an issue that has been exacerbated by population growth resulting in an increased demand for consumerist products, as it is not the growth in urban or rural populations that increases the greenhouse gas emissions, but rather the growth in consumers and in their levels of consumption (Satterthwaite, 2009). Carbon dioxide is known to be the most prominent greenhouse gas emitted as a result of human activity, mainly through the burning of fossil fuels (coal, oil, and natural gas) for energy production, and this is increasing with the population (Dalton et al., 2008). This is more prominent in developing countries, shown by a study made on India and China, which found that carbon dioxide emissions grew due to urbanisation by 25-55%, compared to the model without demographic heterogeneity (Satterthwaite, 2009).
Water scarcity is another serious issue brought by population growth as it’s predicted that within two decades, demand for water will out-strip supply by 40% (Mazur, 2012). The so-called “water crisis” (as often stated by the media) has two dimensions: the physical scarcity of water and the shortage of safe drinking water (usually due to the lack of infrastructure), which areas such as the Horn of Africa experience both of. About a third of the world’s population live in countries with moderate to high water stress; but by 2025 that figure is expected to be two-thirds, and this is due to population growth (Mazur, 2012). Moreover, human numbers are growing where water is scarce. There are forty-five ‘water poor’ countries that are also economically impoverished and physically short on water. They have an average fertility rate of 4.8 children per woman, which is twice the world average (Mazur, 2012). Sandra Postel, the director of the Global Water Policy Project, said that “rapid population growth makes water problems more complicated and more difficult to solve” (Mazur, 2012). This leads to the depletion of groundwater, which then makes food production more difficult in these countries.
The other water crisis is the shortage of clean drinking water, which is faced by nearly a billion people today. In fact, 5 million people die every year due to preventable water-related diseases (UNICEF, 2008). This crisis is evident in fast-expanding cities in the developing world, as although urbanisation is meant to be beneficial and was the driver of economic development in the West and Asia, in Africa, it has brought the rapid growth and consequent urban poverty. This is because the economies are not growing enough to develop the capacity to absorb the growing population and irrigation needed for sanitation (Staff, 2011). Developing regions are expected to take 93% of the urban growth expected by the mid-century, and they are already unable to provide basic services, such as water sanitation, to these new arrivals (Mazur, 2012). Migration from rural areas accounts for roughly 40% of the urban growth, but this is fuelled by the rapid growth of the countryside, where the total fertility rate is higher (Martine, 2007). Therefore, this shows that population growth is a driving force behind the fast urbanisation and brings the challenges of providing safe water to people living in cities.
Following the issue of water is the issue of food security, which is also brought on by rapid population growth. Water for agriculture is vital for future global food security, but due to the growing population leading to a continued increase in demand for water by non-agricultural uses (such as urban and irrigation uses), irrigated water demand has been put under greater scrutiny and thus has threatened food security (Hanjra M, Qureshi M 2010). Despite the fact that there are new investments in irrigation infrastructure to improve water management to partially meet water demand for food production, in arid or semi-arid environments, water is no longer abundant enough to do this (Falkenmark and Molden, 2008). The United Nations found that it is water scarcity, not a lack of arable land, that will be the major limitation in increasing food production in the next few decades (UNDP, 2007).
Half a billion people live in water-stressed or water-scarce countries, and by 2025 that number is expected to be three billion due to the growing population (Molden et al., 2007). As we have seen, the growing population is a massive contributor to the issues arising from water scarcity. Further to this, climate change will impact on crop productivity, which will have implications for food security (Spash, 2008). Countries closer to the equator, such as sub-Saharan African countries, will experience this the most and see food production reduce. This area already has a food security issue, as it’s estimated that in some countries up to 50% of the population are undernourished (FAO et al., 2012). As the growing population impacts on climate change due to there being more greenhouse gases in the year, it is clear that it impacts on food security.
In conclusion, global population growth brings a variety of issues that impact every country. With improvements in medicine and technology resulting in people living longer, in part with a steadily increasing birth rate, these issues will only be exacerbated without careful planning taking place. Although measures can be taken to reduce the challenges, the developing regions often don’t have the money to fund these, as is the case in sub-Saharan Africa. Perhaps the most beneficial and economically viable way to reduce the population growth would be to educate the people of these developing countries about methods such as contraception. Although this is being done to an extent, as seen by the birth rate reducing from 4.5 children in the 1970s to below 2.5 children now, more could be done. Furthermore, sustainable methods have to be put in place in order to make water more available and thus limit the food security crisis.