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A global population of 7.7 billion and growing: are we reaching capacity?

11 July 2019

Olivia Woodhead, Sustainable MPS Investment Assistant
World Population Day, 11th July 2019 

As a global population, we have consumed more resources in the last 50 years than the whole of humanity before us.[1] This is perhaps unsurprising given that the world population was just 1 billion in 1800 and yet hit 6 billion only two centuries later.[2] The current global population stands at just over 7.7 billion people.[3] That is more seven billion human bodies that need to be ideally nurtured, supported and sustained. More than 7.7 billion people who, while consuming resources at an unprecedented rate, are also producing enormous amounts of waste.

Many people are justifiably concerned that an unchecked global population will eventually cause an environmental disaster as the health of our planet continues to decrease. The 7-fold increase of the population over the course of the past two centuries has amplified humanity's impact on the natural environment. However, while the population size is undoubtedly a contributing factor, the issue is larger and far more complex than a head-count. Distribution, composition and consumption patterns all crucially effect the multifaceted relationship between humans and the environment.

Scientists are yet to conclusively determine the ultimate 'carrying capacity' of our planet but, regardless of population size, we only have one planet with a finite level of resources. Critically, the use of resources and the impact of human activity are not equally distributed around the globe and thus the pattern of consumption must be addressed. People in developed countries require substantially more resources to maintain their lifestyle. A stark example is the United States, which contains just 5 percent of the global population and yet produces around 25 percent of CO2 emissions.[4] There is also a blatant difference in the consumption of water. In the 2006 United Nations (UN) Human Development Report, Americans in 2002 were measured to be using 152 gallons of water per day per capita. In comparison, in the same year the citizens of Mozambique only used 4 gallons of water a day with some, alarmingly going without water completely.[5] On a global scale, consumption patterns vary hugely from extreme consumption to areas where basic needs are not being met. An average middle class American has an ecological footprint that is almost 9 times larger than someone living in India.[6] Thus, while population size varies massively from country to country, in terms of environmental degradation, it is especially important that those of us living in developed countries look to address our patterns of consumption.

In 2015, it was estimated that 80 percent of the world's population lived in less developed countries: countries that traditionally have higher birth rates and less infrastructure to support growing populations. But in all countries, our populations are becoming more urbanised. The UN have estimated that by 2050, 66 percent will live in cities. While this increased centralisation would arguably aid the efficiency of resource use; ultimately, the mass movement of people outstrips the rate of development. The pressure that this is already placing on water, energy and food, as well as resulting increased waste, is causing localised environmental problems. However, it is not just planned migration that is causing environmental challenges. The last decade has seen an explosion in the unplanned migration of refugees, particularly from the Middle East since 2011. The sudden development of refugee camps caused enormous strains on the environment, from water supplies, land damage and pollution from human and material waste.[7]

Population composition is another crucial constituent in the interplay between population and the planet. Population ageing is set to become one of the most significant social transformations of the century, with implications for all sectors and geographies. According to data from World Population Prospects in 2017, the number of people aged over 60 years or more is expected to double by 2050 to 2.1 million and more than triple by 2100 to 3.1 billion, growing faster than all younger age groups.[8] An ageing global population undoubtedly places stress on social infrastructure, especially healthcare, as well as government spending on pensions and implications for the workforce.

The human species is consuming our planet and with more than 7.7 billion other people around us, it is easy to assume that someone else will tackle the challenges we face. The UN's celebration of World Population Day on 11th July each year, seeks to focus attention on the urgency and importance of population related issues. Population growth alone is not the issue but it undoubtedly intensifies and exacerbates the global challenges we face. It is essential that leaders, policy makers, organisations, institutions and the global community recognise the complex relationship between population and our planetary existence.

[1] https://www.science.org.au/curious/earth-environment/population-environment

[2] https://www.researchgate.net/publication/237771340_IMPACT_OF_POPULATION_EXPLOSION_ON_ENVIRONMENT

[3] https://www.worldometers.info/world-population/

[4] https://sciencing.com/environmental-problems-due-population-growth-8337820.html

[5] https://www.seametrics.com/blog/us-water-use-compared-to-the-rest-of-the-world/

[6] https://www.science.org.au/curious/earth-environment/population-environment

[7] https://www.science.org.au/curious/earth-environment/population-environment

[8] https://www.un.org/en/sections/issues-depth/ageing/