Overshoot (population)

In environmental science, a population "overshoots" its local carrying capacity — the capacity of the biome to feed and sustain that population — when that population has not only begun to outstrip its food supply in excess of regeneration, but actually shot past that point, setting up a potentially catastrophic crash of that feeder population once its food populations have been consumed completely. Overshoot can apply to human overpopulation as well as other animal populations: any life-form that consumes others to sustain itself.

For other uses, see Overshoot (disambiguation).

Environmental science studies to what extent human populations through their resource consumption have risen above the sustainable use of resources. For people, "overshoot" is that portion of their demand or ecological footprint which must be eliminated to be sustainable, or the delta between a sustainable population and what we currently have.[1][2] Excessive demand leading to overshoot is driven by both consumption and population.[3]

Population decline due to overshoot is known as 'collapse'. The path taken by such a population is referred to as 'overshoot-and-collapse'. Collapse, like overshoot, can occur due to various factors, with the Malthusian catastrophe being a specific but not identical case.

Overshoot can happen as a result of delayed impacts, where reproduction rates persistently surpass the death rate.[4] This can lead to significant consequences, with entire ecosystems being profoundly impacted and sometimes simplified due to prolonged overshoot.[5] An instance of this phenomenon took place in the Horn of Africa when smallpox was eradicated, causing a sudden increase in the population that exceeded the region's carrying capacity. For centuries, the land had sustained approximately 1 million pastoralists, but with the elimination of the disease, the population suddenly grew to 14 million people. Consequently, overgrazing occurred, leading to soil erosion.[6]

The most famous example of an overshoot-and-crash may be from St. Matthew Island. In 1944, 29 reindeer were introduced to the island, which by 1963 had grown to a peak population of roughly 6000 individuals — well past the estimated carrying capacity. At next count, in 1965, the population had plummeted and only 42 reindeer were left alive.

Thomas Malthus (1766-1864) is perhaps the most well-known writer to have articulated the roots of the modern concept of human overshoot, with The Population Bomb (1967) by Paul Ehrlich reigniting the hotly-debated topic in more recent history. Daniel Quinn claims to have modernized the concept of human overpopulation in what are likely the most well-read volumes to have given it extensive treatment as a subject of ecology: The Story of B (1996) and My Ishmael (1997).

Human overshoot
Main articles: Overconsumption and Sustainable population
See also: Earth Overshoot Day, Human impact on the environment, and Human ecology

The 1972 book The Limits to Growth discussed the limits to growth of society as a whole. This book included a computer-based model which predicted that the Earth would reach a carrying capacity of ten to fourteen billion people after some two hundred years, after which the human population would collapse.[7] The model was based on five variables: "population, food production, industrialization, pollution, and consumption of non-renewable natural resources".[8]: 25  This simulation modelled human populations after the overshoot and collapse seen in all unmoderated species. It was controversial and generally dismissed by economists.[9]

Sociologist William R. Catton, Jr. explored the connections between human societies and the natural environment in his book Overshoot published in 1980. Catton expressed his concerns about the global population exceeding Earth's sustainable limits, advocating that a reduction in population through natural means, such as mortality, was necessary. He argued that the predicament stemmed from both overpopulation, where the number of people surpassed what the planet could support, and overconsumption, referring to the excessive utilization of resources. Catton predicted that unless these issues were addressed, humanity would surpass the Earth's optimal carrying capacity, leading to potentially dire consequences.[10][11][12]

The Global Footprint Network purports to be able to measure how much the human economy demands against what the Earth can renew.[13][14] The Optimum Population Trust (now called Population Matters) has listed what they believe is the overshoot (overpopulation) of a number of countries, based on the above.[15]

In one study[16] published in January 2021 in Frontiers in Conservation Science, the significance of overshoot is discussed. It says that alongside the growth of the global population, humanity's consumption relative to Earth's regenerative capacity has surged by 73% in 1960 to 170% in 2016, particularly in countries with higher incomes.[17] These findings are based on recent ecological footprint studies.[18]

An article in Frontiers in Conservation Science also says ecological overshoot has been facilitated by the increasing reliance on fossil fuels. The widespread use of convenient energy sources has allowed human demand to detach from the limits of biological regeneration. Notably, fossil fuels account for 85% of commercial energy production, 65% of fiber production, and serve as the primary raw material for most plastics.[17]

As a possible cause for societal collapse, overshoot has been scholarly discussed, but has not been found having been the cause for historic cases of collapse.[19]

Predictions of scarcity
See also: Water scarcity
Greater Los Angeles lies on a coastal mediterranean savannah with a small watershed that is able to support at most one million people on its own water; as of 2015, the area has a population of over 18 million. Researchers predict that similar cases of resource scarcity will grow more common as the world population increases.[20]

British scholar Thomas Malthus, in his seminal work published in 1798 titled An Essay on the Principle of Population, forecast the potential depletion of the world's food resources due to the growth of human population. Malthus composed this essay with the intention of refuting the impractical utopian concepts advocated by William Godwin and Marquis de Condorcet in their respective works, namely Political Justice and The Future Progress of the Human Mind. In 1968, Paul R. Ehrlich revived Malthus' argument in his book The Population Bomb, wherein he anticipated an impending global famine of catastrophic proportions.[21]

The predictions of Ehrlich and other neo-Malthusians were challenged by a number of economists, notably Julian Lincoln Simon, who said advances in agriculture, collectively known as the Green Revolution, forestalled any potential global famine in the late 20th century. Notably, between 1950 and 1984, the Green Revolution transformed agriculture around the world and grain production increased by over 250%.[22] The world population has grown by over four billion since the beginning of the Green Revolution, but food production has so far kept pace with population growth. Most scholars believe that, without the Green Revolution, there would be greater levels of famine and malnutrition than the UN presently documents.[23] However, neo-Malthusians point out that fossil fuels provided the energy for the Green Revolution, in the form of natural gas-derived fertilizers, oil-derived pesticides, and hydrocarbon-fueled irrigation, and that many crops have become so genetically uniform that a crop failure in any one country could potentially have global repercussions.[24]

In May 2008, the price of grain rose because of the increased cultivation of biofuels, the increase of world oil prices to over $140 per barrel ($880/m3),[25] global population growth,[26] the effects of climate change,[27] the loss of agricultural land to residential and industrial development,[28][29] and growing consumer demand in the population centres of China and India.[30][31] Food riots subsequently occurred in some countries.[32][33] However, oil prices then fell sharply. Resource demands are expected to ease as population growth declines, but it is unclear whether mass food wastage and rising living standards in developing countries will once again create resource shortages.[34][35]

David Pimentel, professor of ecology and agriculture at Cornell University, estimates that the sustainable agricultural carrying capacity for the United States is about 200 million people; its population as of 2015 is over 300 million.[36] In 2009, the UK government's chief scientific advisor, Professor John Beddington, warned that growing populations, falling energy reserves and food shortages would create a "perfect storm" of shortages of food, water, and energy by 2030.[20][37] According to a 2009 report by the United Nations Food and Agriculture Organization (FAO), the world will have to produce 70% more food by 2050 to feed a projected extra 2.3 billion people.[38]

The figures for 2007 showed an actual increase in absolute numbers of undernourished people in the world, with 923 million undernourished in 2007, versus 832 million in 1995.[39] The 2009 FAO estimates showed an even more dramatic increase, to 1.02 billion.[40]

Human impact on the environment
Illegal slash-and-burn agriculture in Madagascar, 2010

A number of scientists have argued that the looming human impact on the environment and accompanying increase in resource consumption threatens the world's ecosystem and the survival of human civilization.[41][42][43][17] Scientists contend that continued human population growth and overconsumption, particularly by the wealthy, are the primary drivers of mass species extinction[44][45][46] and some suggesting human overpopulation as a driver.[47]

Human population planning
A government sign in China: "For a prosperous, powerful nation and a happy family, please practice family planning."

Human population planning is the practice of intervening to alter the rate of population growth. Historically, human population control has been implemented by limiting a region's birth rate, by voluntary contraception or by government mandate. It has been undertaken as a response to factors including high or increasing levels of poverty, environmental concerns, and religious reasons. The use of abortion in some population control strategies has caused controversy,[48] with religious organizations such as the Roman Catholic Church explicitly opposing any intervention in the human reproductive process.[49]

The University of Nebraska publication Green Illusions argues that population control to alleviate environmental pressures need not be coercive. It states that "Women who are educated, economically engaged, and in control of their own bodies can enjoy the freedom of bearing children at their own pace, which happens to be a rate that is appropriate for the aggregate ecological endowment of our planet."[50] The book Fatal Misconception by Matthew Connelly similarly points to the importance of supporting the rights of women in bringing population levels down over time.[51] Paul Ehrlich also advocates making "modern contraception and back-up abortion available to all and give women full equal rights, pay and opportunities with men," noting that it could possibly "lead to a low enough total fertility rate that the needed shrinkage of population would follow. [But] it will take a very long time to humanely reduce total population to a size that is sustainable." Ehrlich places the optimum global population size at 1.5 to 2 billion people.[52]

Other academicians and public figures have pointed to the role of agriculture and agricultural productivity of increasing human carrying capacity, which results in population overshoot, as with any other species when their food supply experiences an increase, which in turn results in resource depletion and mass poverty and starvation in the case of humans.[53][54][55][56]

See also

References
  1. Global Footprint Network. (2010). The Ecological Footprint Atlas 2010
  2. Schreef, Nathan Surendran (2014-12-01). "Humans in ecological overshoot: Collapse now to avoid a larger catastrophe". The Seneca Effect. Retrieved 2017-05-16.
  3. "Media Backgrounder; Earth Overshoot Day; 6. Population and Consumption". Earth Overshoot Day. Global Footprint Network. 2021. Retrieved 22 January 2021.
  4. Schmitz, Oswald J. (2013). Ecology and Ecosystem Conservation. Island Press. p. 51. ISBN 978-1-59726-598-0. Retrieved 2 August 2016.
  5. Howes, Michael (2011). "Development and Ethical Sustainability". In Newman, Julie (ed.). Green Ethics and Philosophy: An A-to-Z Guide Volume 8 of The SAGE Reference Series on Green Society: Toward a Sustainable Future-Series Editor: Paul Robbins. SAGE Publications. p. 114. ISBN 978-1-4522-6622-0. Retrieved 2 August 2016.
  6. Debora MacKenzie (10 October 2011). "Low-key projects keep Horn of Africa famine at bay". NewScientist. Reed Business Information. Retrieved 11 October 2011.
  7. Meadows, Donella; Jørgen Randers; Dennis Meadows (2004). Limits to growth: The 30-year update. White River Junction, VT: Chelsea Green Publishing Company. p. 337. ISBN 1931498512.
  8. Meadows, Donella H; Meadows, Dennis L; Randers, Jørgen; Behrens III, William W (1972). The Limits to Growth; A Report for the Club of Rome's Project on the Predicament of Mankind. New York: Universe Books. ISBN 0876631650. Retrieved 26 November 2017.
  9. Sharpe, M.E. (2015). Economic Abundance: An Introduction. M.E. Sharpe. p. 67. ISBN 978-0765628084. Retrieved 2 August 2016.
  10. William R. Catton, Jr. (1980). Overshoot: The Ecological Basis of Revolutionary Change. University of Illinois Press. ISBN 978-0252008184.
  11. Ryerson, W. F. (2010), "Population, The Multiplier of Everything Else", in McKibben, D. (ed.), The Post Carbon Reader: Managing the 21st Century Sustainability Crisis, Watershed Media, ISBN 978-0-9709500-6-2
  12. Brown, L. R. (2011). World on the Edge. Earth Policy Institute. Norton. ISBN 978-0-393-08029-2.
  13. Mathis Wackernagel, Niels B. Schulz, Diana Deumling, Alejandro Callejas Linares, Martin Jenkins, Valerie Kapos, Chad Monfreda, Jonathan Loh, Norman Myers Richard Norgaard and Jørgen Rander (May 16, 2002). "Tracking the ecological overshoot of the human economy". Retrieved 2 August 2016.
  14. Wackernagel, Mathis; Lin, David; Evans, Mikel; Hanscom, Laurel; Raven, Peter (2019). "Defying the Footprint Oracle: Implications of Country Resource Trends". Sustainability. 11 (7): 2164. doi:10.3390/su11072164.
  15. "New index highlights most overpopulated countries". populationmatters.org. Optimum Population Trust. 10 April 2012. Retrieved 10 April 2012.
  16. "Loop | Publication Impact | Underestimating the Challenges of Avoiding a Ghastly Future".
  17. Bradshaw, Corey J. A.; Ehrlich, Paul R.; Beattie, Andrew; Ceballos, Gerardo; Crist, Eileen; Diamond, Joan; Dirzo, Rodolfo; Ehrlich, Anne H.; Harte, John; Harte, Mary Ellen; Pyke, Graham; Raven, Peter H.; Ripple, William J.; Saltré, Frédérik; Turnbull, Christine; Wackernagel, Mathis; Blumstein, Daniel T. (2021). "Underestimating the Challenges of Avoiding a Ghastly Future". Frontiers in Conservation Science. 1. doi:10.3389/fcosc.2020.615419.
  18. Lin, D; Hanscom, L; Murthy, A; Galli, A; Evans, M; Neill, E; Mancini, MS; Martindill, J; Medouar, F-Z; Huang, S; Wackernagel, M. (2018). "Ecological Footprint Accounting for Countries: Updates and Results of the National Footprint Accounts, 2012–2018". Resources. 7(3): 58. https://doi.org/10.3390/resources7030058
  19. Joseph A. Tainter (2006). "Archaeology of Overshoot and Collapse". Annual Review of Anthropology. 35: 59–74. doi:10.1146/annurev.anthro.35.081705.123136.
  20. "World faces 'perfect storm' of problems by 2030, chief scientist to warn". The Guardian. 18 March 2009. Archived from the original on 14 November 2016. Retrieved 18 February 2013.
  21. Jowit, Juliette (23 October 2011). "Paul Ehrlich, a prophet of global population doom who is gloomier than ever". The Guardian. London. Archived from the original on 1 October 2013. Retrieved 22 July 2013.
  22. Kindall, Henery W & Pimentel, David (May 1994). "Constraints on the Expansion of the Global Food Supply". Ambio. 23 (3). Archived from the original on 11 October 2018. Retrieved 10 August 2009.
  23. "The limits of a Green Revolution?". BBC News. 29 March 2007. Archived from the original on 28 July 2011. Retrieved 18 February 2013.
  24. "Host Plant Resistance and Conservation of Genetic Diversity". Radcliffe's IPM World Textbook. University of Minnesota. March 2013. Archived from the original on 3 November 2013. Retrieved 20 July 2013.
  25. "The global grain bubble". The Christian Science Monitor. 18 January 2008. Archived from the original on 30 November 2009. Retrieved 18 February 2013.
  26. James Randerson, science correspondent (7 March 2008). "Food crisis will take hold before climate change, warns chief scientist". The Guardian. London. Archived from the original on 2 September 2013. Retrieved 18 February 2013.
  27. John Vidal (3 November 2007). "Global food crisis looms as climate change and fuel shortages bite". The Guardian. London. Archived from the original on 30 September 2013. Retrieved 18 February 2013.
  28. Walsoft (22 February 2008). "Experts: Global Food Shortages Could 'Continue for Decades'". Marketoracle.co.uk. Archived from the original on 21 February 2013. Retrieved 18 February 2013.
  29. Moya K. Mason. "Has Urbanization Caused a Loss to Agricultural Land?". Moyak.com. Archived from the original on 24 September 2013. Retrieved 9 July 2013.
  30. Walt, Vivienne (27 February 2008). "The World's Growing Food-Price Crisis". Time. Archived from the original on 29 November 2011. Retrieved 18 February 2013.
  31. "The cost of food: Facts and figures" Archived 20 January 2009 at the Wayback Machine. BBC. 16 October 2008. Retrieved 18 February 2013.
  32. Julian Borger (26 February 2008). "Feed the world? We are fighting a losing battle, UN admits". The Guardian. London. Archived from the original on 25 December 2016. Retrieved 18 February 2013.
  33. Buchanan, Emily (22 April 2008). "Assessing the global food crisis". BBC News. Archived from the original on 15 January 2009. Retrieved 6 April 2010.
  34. "Half of all food 'wasted' report claims". BBC. 10 January 2013. Archived from the original on 10 January 2013. Retrieved 10 January 2013.
  35. "Oil shock could push world food prices higher". CNN Money. 3 March 2011. Archived from the original on 9 March 2013. Retrieved 18 February 2013.
  36. P. Crabbè (2000). Implementing ecological integrity: restoring regional and global environmental and human health. North Atlantic Treaty Organization Scientific Affairs Division/Springer. p. 411. ISBN 978-0792363514.
  37. "Global crisis 'to strike by 2030". BBC News. 19 March 2009. Archived from the original on 15 November 2016. Retrieved 18 February 2013.
  38. "Global food production will have to increase 70% for additional 2.3 billion people by 2050". Finfacts.com. 24 September 2009. Archived from the original on 10 March 2016. Retrieved 18 February 2013.
  39. "The State of Food Insecurity in the World, 2008: High food prices and food security – threats and opportunities". UN Food and Agriculture Organization – Economic and Social Development Department. 2008. p. 2. Archived from the original on 13 June 2018. Retrieved 8 December 2012.
  40. "One sixth of humanity undernourished – more than ever before". Food and Agriculture Organization of the United Nations. 2009. Archived from the original on 17 November 2012. Retrieved 8 December 2012.
  41. "Ecological Debt Day". Archived from the original on December 17, 2008. Retrieved February 18, 2013.
  42. "Planetary Boundaries: Specials". Nature. 23 September 2009. Archived from the original on 12 February 2013. Retrieved 18 February 2013.
  43. Bologna, M.; Aquino, G. (2020). "Deforestation and world population sustainability: a quantitative analysis". Scientific Reports. 10 (7631): 7631. arXiv:2006.12202. Bibcode:2020NatSR..10.7631B. doi:10.1038/s41598-020-63657-6. PMC 7203172. PMID 32376879.
  44. Pimm, S.L.; Jenkins, C.N.; Abell, R.; Brooks, T.M.; Gittleman, J.L.; Joppa, L.N.; Raven, P. H.; Roberts, C. M.; Sexton, J. O. (30 May 2014). "The biodiversity of species and their rates of extinction, distribution, and protection" (PDF). Science. 344 (6187): 1246752. doi:10.1126/science.1246752. PMID 24876501. S2CID 206552746. Archived (PDF) from the original on 31 August 2019. Retrieved 15 December 2016. The overarching driver of species extinction is human population growth and increasing per capita consumption.
  45. Ceballos, Gerardo; Ehrlich, Paul R.; Barnosky, Anthony D.; García, Andrés; Pringle, Robert M.; Palmer, Todd M. (2015). "Accelerated modern human–induced species losses: Entering the sixth mass extinction". Science Advances. 1 (5): e1400253. Bibcode:2015SciA....1E0253C. doi:10.1126/sciadv.1400253. PMC 4640606. PMID 26601195.
  46. Sutter, John D. (12 December 2016). "How to stop the sixth mass extinction". CNN. Archived from the original on 12 January 2017. Retrieved 19 December 2016.
  47. Ceballos, Gerardo; Ehrlich, Paul R; Dirzo, Rodolfo (23 May 2017). "Biological annihilation via the ongoing sixth mass extinction signaled by vertebrate population losses and declines". PNAS. 114 (30): E6089–E6096. Bibcode:2017PNAS..114E6089C. doi:10.1073/pnas.1704949114. PMC 5544311. PMID 28696295. Much less frequently mentioned are, however, the ultimate drivers of those immediate causes of biotic destruction, namely, human overpopulation and continued population growth, and overconsumption, especially by the rich. These drivers, all of which trace to the fiction that perpetual growth can occur on a finite planet, are themselves increasing rapidly.
  48. Some population control programs, such as China's one-child policy, entail the use of forced late-term abortions, sparking domestic anger and international condemnation: "China one-child policy leads to forced abortions, mothers' deaths". Los Angeles Times. 15 June 2012. Archived from the original on 29 August 2012. Retrieved 29 August 2012.
  49. "Fighting poverty to build peace". Vatican. 1 January 2009. Archived from the original on 11 October 2011. Retrieved 24 October 2011.
  50. Zehner, Ozzie (2012). Green lllusions. Lincoln and London: University of Nebraska. p. 188. Archived from the original on 29 November 2019. Retrieved 10 April 2020.
  51. Connelly, Matthew (2008). Fatal Misconception: The Struggle to Control World Population. ISBN 978-0674029835.
  52. Carrington, Damian (22 March 2018). "Paul Ehrlich: 'Collapse of civilisation is a near certainty within decades'". The Guardian. Retrieved 23 August 2020.
  53. Cite Warren, Stephen G. "Did agriculture cause the population explosion?." Nature 397.6715 (1999): 101.
  54. "Morgan Freeman on the 'Tyranny of Agriculture' and the Doomed Human Race". ecorazzi. 19 February 2014.
  55. Armelagos, George J.; Goodman, Alan H.; Jacobs, Kenneth H. (1 September 1991). "The origins of agriculture: Population growth during a period of declining health". Population and Environment. 13 (1): 9–22. doi:10.1007/BF01256568. ISSN 1573-7810. S2CID 153470610.
  56. "Agriculture and Human Population Growth". CK-12.

Further reading
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