Rajeev Pratap Singh
Banaras Hindu University, India
University of Allahabad, India
Banaras Hindu University, India
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Overpopulation has recognized as a global environmental problem since few decades, as it has caused
a number of adverse eﬀects on environment. Modern medical facilities and illiteracy in some interior
regions of developing countries are the major reasons for development of this inverted pyramid demo-
graphic structure. Overpopulation has resulted in a series of catastrophic consequences by causing
increased pressure on existing natural resources. Deforestation, eﬀect on welfare, climate change, decline
in biocapacity, urban sprawl, food security, increase in energy demand and eﬀect on marine ecosystem
are amongst most severe impacts of overpopulation. Concrete steps need to be taken on national and
international level to combat the adverse eﬀects of overpopulation, so that sustainability of natural
resources can be ensured for future generations.
The world’s population has touched a mark of 7.3 billion in 2015 and could attain growth level of 9-12
billion before the year 2050 which suggest that the impact of overpopulation can increase the pace of
ecological changes and impose a burden on biodiversity (Sala et al., 2000; UN, 2015). The 49 least
developed countries have shown a growth rate of 2.3% annually, which was nearly twice as compared
to the developing world i.e. 1.2% per year in the year 2009 (UN, 2009). Increases in human population
size have caused an increased risk of synergies among impacts with resultant accelerated environmental
degradation (Harte, 2007). This increase in population size has fastened the agricultural activities and
technological development up to the extent, which is catastrophic to environmental health. The negative
effect of an agriculture or technological society on the abiotic and biotic components of the environment
can be expressed in the simplest terms, by the relation,
Impact on Environment
Banaras Hindu University, India
Kurukshetra University, India
Kurukshetra University, India
R. K. Sharma
Banaras Hindu University, India
I = P.F
where P and F denotes the population and function, respectively which measures impact per capita
(Ehrlich and Holdren, 1971). Thus, to reduce environmental degradation and to ensure sustainability
of natural resources, better understanding of potential impacts of overpopulation on environmental and
human health are required.
An exponential growth of human population over the last few centuries has caused encroachment in
the wild habitats and their consequent destruction, posing a potential threat to biodiversity components
(Vinod, 2012). Growth rate of world population was approximately 2% per annum from 1960-2000,
which indicted potential population doubling every 35 years thus could cause ecological unsustain-
ability (Bloom, 2011). Projected world population growth for the major regions is presented in Table 1.
Improved agriculture practices, modern medical facilities and illiteracy in rural regions caused demo-
graphic transition with more natality rate and decline in mortality rate. From 1980–81 until 1999–2000,
agriculture showed a growth rate of 3.2% per annum, which exceeds the population growth rate of 2.0%
annually over the period, while annual growth rate of per capita income was 3.1% between 1980 and
1991 and 4.3% since there forms of 1991 (Lal, 2006). According to the Inter Academy Panel Statement
on Population Growth, several environmental concerns such as, elevated level of greenhouse gases,
threat to biodiversity, climate change and environmental pollution are arisen as a result of rapid popula-
tion growth (Coleman, 2011; Edet et al., 2014). This chapter reviews the impacts of overpopulation on
environment, indicates future perspectives and provides some recommendation to combat the adverse
impact of overpopulation.
Table 1. Projected World Population Growth for Major Regions
Regions 2010 Population (millions) 2050 population Projections (millions)
Low fertility Medium fertility High fertility
Africa 1,022 1,932 2,192 2,470
Asia 4,164 4,458 5,142 5,898
and Caribbean 590 646 751 869
Europe 738 632 719 814
America 345 396 447 501
Oceania 37 49 55 62
regions 1,236 1,158 1,312 1,478
regions 5,660 6,955 7,994 9,136
World 6,896 8,112 9,306 10,614
Source: United Nations, Department of Economic and Social Affairs, Population Division. (2010). World Population Prospects: The
IMPACTS OF OVERPOPULATION
Overpopulation has severe environmental implications. Although it has contributed in the nation’s economy
at global level, but has caused some adverse impacts on environment, which need to be addressed (Fig-
ure 1). Table 2 summarizes evolution of environmental concern, associated with population explosion.
Figure 1. Effect of overpopulation on Environment
Table 2. Evolution of environmental concerns from 1940s to the present (modified)
Decade Environmental effect Source
1940-1950 Depletion of natural resources United Nations report on population and resources
1960-1970 Air Pollution, Water pollution, Radioactive
pollution, Disposal of waste
Declaration of the United Nations Conference on the Human
Environment World Population Plan of Action of the United
Nations World Population Conference
1980-1990 Climate change, Ozone depletion, Acid rain
Reports of the United States National Academy of Sciences
Agenda 21 adopted by the United Nations Conference
on Environment and Development Recommendations of the
International Conference on Population
Control of emergence and re-emergence of
diseases, Biodiversity loss
Globalization Programme of
Action of the International Conference on Population and
Development Resolution S-21/2 on key actions for the further
implementation of the Programme of Action adopted by the
General Assembly at its twenty-first special session
Source: (Ruttan, 1993)
Increasing urbanization has triggered deforestation at a very fast pace, in order to fulfill infrastructure
demand of increasing population. Lands with high canopy covers are being subjected to deforestation and
people are continuing to migrate from rural areas to urban areas. According to World Migration Report
(2015), net migration from rural to urban area during 1981–1991 was 11 million which has risen during
2001-2011 to 19 million, in India. Population growth caused an exponential increase in the alternation
of the land utilization patterns to supplements economic needs in the form of agricultural products, fuel
wood, timber etc. However, to control conversion of forest area to agricultural, industrial and residential
area, Forest (Conservation) Act was enacted in the year 1980 in India as a result of which conversion
of forest area to other land use practices was reduced with the annual diversion rate of 16,000 hectare
(Economic Survey of India, 1998-99; Nagdeve, 2002).
Overpopulation has severely affected the quality of life in recent years. Quality of life (QOL) of individu-
als is an approach used to determine their satisfaction in:
• Financial status,
• Social life,
• Family life,
• Health and
According to Quality-of-Life Index, 2005, Ireland ranks first in the quality of life, with comparatively
low population in comparison with countries such as China and India which ranks 60 and 73, respectively.
Increasing population has imposed a burden on existing recourses to fulfill the basic needs of such huge
population, which resulted in elevated poverty percentage. According to Planning Commission, India,
below poverty line population living in the rural area showed a sharp increase from 27.09% in 1999 to
41.79% in the year 2005. This increase is subsequently accelerating lack of education in a mass of poor
population. It tends to increase fertility rate in illiterate and poor population, which is not much aware
about degrading environmental quality due to increasing population. Table 3 represents general fertility
rate of women by their education level in different states of India. Kerala showed lowest i.e. 1.3% of illiter-
ate women, while Bihar represents highest illiteracy i.e. 51.1% of illiterate women. General fertility rate
was found to be lower for literate women as compare to illiterate women in all states of India. However,
states showed lower value of general fertility rate for illiterate population than the literate population
which was ascribed to the fact that sample size in illiterate category was quite small as theses states have
significantly high literacy level (Census of India, 2011). In addition, government of developing countries
like India is not able to manage medical facilities to such huge amount of population.
Recent reports on climate change indicated more frequency and catastrophe in the weather extremes,
leading to costly damage of infrastructure and loss of human life (Intergovernmental Panel on Climate
Change, 2007). Increased use of fossil fuels since the mid-19th century in overpopulated regions around
the globe caused release of over 1100Gt CO2 into the atmosphere (IPCC, 2001). Furthermore, over-
population accelerated agricultural practices, leading to enhanced emission of greenhouse gases. For
example, methane is produced from rice agriculture practices and livestock. For emission of greenhouse
gases, agriculture sources in 2014 accounted for 24% of 2010 global emission (IPCC, 2014). Popula-
tion reduction in high-income countries might act as a possible solution. Any reduction in population
growth in high-income countries, even starting from zero or negative rates, will have much more impact
on reducing climate change than the same size reduction in low-income countries, because of the much
higher per capita consumption and emission of greenhouse gases in the high-income countries (Rosnick,
2014). In addition, switch to alternative energy options (solar energy, tidal energy, wind energy etc) and
Table 3. General fertility rate by level of education of women in India and bigger States, 2011
India and bigger States
General fertility rate
Illiterate Total literate
India 86.7 78.7
Andhra Pradesh 43.4 71.5
Assam 103.0 76.8
Bihar 144.7 83.0
Chhattisgarh 62.9 107.8
Delhi 76.3 60.2
Gujarat 82.4 78.5
Haryana 61.7 87.9
Himachal Pradesh 18.4 62.8
Jammu & Kashmir 79.7 53.6
Jharkhand 109.7 83.7
Karnataka 41.5 75.2
Kerala 15.3 54.7
Madhya Pradesh 93.9 109.2
Maharashtra 34.0 68.8
Odisha 72.3 72.8
Punjab 52.4 62.2
Rajasthan 104.6 99.8
Tamil Nadu 11.1 62.2
Uttar Pradesh 115.4 105.4
West Bengal 46.9 61.4
Source: (Census of India, 2011)
improved agricultural practices could help in combating the problem of climate change resulting from
Decline in Biocapacity
Increasing global population has accelerated resource consumption, which subsequently increased pres-
sure on existing natural resources to unprecedented levels. Biocapacity is the area available as productive
land and available water to produce resources or absorb carbon dioxide waste, given current management
practices (Ecological Footprint Atlas, 2010). Biocapacity seems to decline sharply with increased pres-
sure on ecological resources, as existing resources could not support consumption need of such a wide
world population. Biocapacity per head decreased from 3.2 global hectares (gha) in 1961 to 1.8 gha
per capita in 2008, even though total global biocapacity increased over this time (WWF Living Planet
Report, 2012). The Ecological footprint denotes the land area required to meet the consumption and
waste absorption needs of a population (Wackernagel & Rees, 1995). It can be used to track the avail-
ability and consumption of ecological resources and thus can aid in sustainable utilization of resources.
According to Ecological Footprint accounts, demand for renewable resources has increased from 7.6
billion global hectares in 1961 to 18.1 billion global hectares in 2010. Similarly, global bioproductive
area showed an increase from 9.9 billion global hectares in 1961 to 12 billion global hectares in 2010,
indicating its unsustainable status (Global Footprint Network, 2015).
Urban sprawl is one of the several consequences of rapid population growth. Sprawl is a large scale
development process of real estate, producing low density, scattered, discontinuous car-dependent con-
struction, usually on the periphery of the declining older suburbs and shrinking city centers (Hayden,
2004). Urban global population will grow to 4.9 billion by 2030, while, the global rural population is
predicted to decline by approximately 28 million during 2005 to 2030 (Bhatta, 2010). In the United
States, urban growth is expected to utilize about 19 million acres of farmland, environmentally sensi-
tive and other lands during 2000–2025 (Burchell et al., 2005). Urban sprawl can be caused either by
increased natality rate or by increased immigration. Better living facilities and need employment of
employment are the major factors, which caused migration of population from rural area to urban area.
Governmental organizations cannot deliver all basic services and quality life to huge urban population
and thus, resulting massive sprawl may cause severe environmental degradation.
Overpopulation has worsened the local and global food security by synergistic impacts of climate change.
Emission from agriculture sources elevated from 4.7 billion tonnes to over 5.3 billion tonnes of carbon
dioxide equivalents (CO2 eq) during 2001-2011 (Food and Agriculture Organization, 2014). Climate
change resulting from the enhanced emission of greenhouse gases has posed a severe threat on food
security by affecting agricultural crop production and biodiversity. Food security is linked with food
availability, accessibility and utilization. Increasing urbanization has limited the growth of agricultural
sectors by encouraging industrial development in rural regions. Current food production is becoming
limited along with the hasty growth in human population numbers. Technological development in the
field of agriculture depends on availability of natural resources like water, land and energy. For instance,
1 kcal of food production requires about 10 kcal of fossil energy, which is present in limited amount and
thus restrict the progress in agriculture production (Pimentel, 2011). Currently, agricultural land suit-
able for irrigation is 50% of the world’s land. This land area is continuously being shrinking due to soil
erosion, nutrient depletion, soil acidification and soil salination (Horizon, 2009).
Increase in Energy Demand
Growing global population has caused rapid inflation in energy requirement and consumption. Accord-
ing to Energy Information Administration (2001), use of energy, mostly for fossil fuels has boosted by
nearly 85 percent globally during past 30 years, while for Asia, it is more than 300%. Sustainability for
energy resources can be assured by the increased use of renewable resources, utilizing energy conserv-
ing devices for household purposes and development of advanced technologies for generating energy
from biological sources.
Effect on Marine Ecosystem
Overpopulation in coastlines has mainly resulted from migration activities and caused severe environmen-
tal degradation. Mangroves, fisheries and beaches used commercially for tourism purposes are among
the coastal resources, which are severely damaged by consumption practices (Naylor et al., 2002). Coral
reefs are being rapidly degraded both due to direct impact of climate change and by human induced
marine pollution, overfishing etc. Out of the 19,210 km2 of coral reefs in South Asia, 45% of have been
destroyed, while 10%, 25% and 20% are critically threatened, threatened and at low risk, respectively
(Tun et al., 2004). In Mesoamerican Barrier Reef, coral cover is declining at an average rate of about 11%
since 2004, with more than 50% cover loss for some reefs (Wilkinson, 2008). International agreements
for conserving marine biodiversity have however caused a significant increase in several biodiversity
rich marine regions but increasing population is still a hurdle for their successful implementations.
ISSUES, CONTROVERSIES, PROBLEMS
Several efforts are being taken to ensure reduction of adverse impacts of overpopulation on environment
but these are associated with serious issues. For example, developing countries are being funded under
clean development mechanism to increase plantation practices, but simultaneous deforestation, has
checked the advantages emerging out of the strategy. Huge population in rural regions is still dependent
on fossil fuels for energy needs. Although renewable energy programmes are being initiated in rural
regions by various governmental organizations but the success of these programmes always remains on
question. No maintainers are provided for the solar panels after their installment. As a result, most of
such renewable energy devices remain in non-working condition. Several schemes are being hurled by
government of India to provide employment in the rural areas so that the massive urban sprawl can be
checked. Government of India inducted a scheme for self-employment in 1980-81 namely, Integrated Rural
Development Programme (IRDP), which was further remodeled as the Swarnjayanti Gram Swarozgar
Yojana (SGSY). In 1989, Jawahar Rozgar Yojana (JRY) was initiated by amalgamating National Rural
Employment Programme (NREP) and Rural Landless Employment Guarantee Programme (RLEGP).
The main goal of the scheme was generating more employment opportunities for people living in rural
areas, advancing rural infrastructure and quality of life (Planning Commission, Government of India).
However, it turns out to be a very time consuming process for procuring actual financial gain by rural
people due to red tapism involved in governmental procedures especially in developing nations. In ad-
dition, to ensure food security, use of enormous quantity of chemical fertilizers further worsened the
environmental health by reducing soil fertility.
POSITIVE EFFECTS OF OVERPOPULATION
As a major problem many scientists agreed that human population may reach the point at which the
earth will no more able to sustain life. However, many believe that ever increasing population have some
advantages such as:
• Economic beneﬁts,
• Increased human resources,
• Higher demand in industries,
• Innovative, cheaper and
• More readily available products etc.
A nation with high population and/or increasing number of youth can add more people to devel-
opmental activities. An increasing population can boost the economic growth of a country only if the
demand for better services grows. Therefore, to yield positive effects from growing population a nation
must have sound policies. Keeping the pace with population growth, countries that utilize their human
resources efficiently in developing better health care and medicine, food production,
SOLUTIONS AND RECOMMENDATIONS
The impact of overpopulation on food security can be reduced by raising food production, improving
food distribution and by increasing economic access to food (Gregory et al., 2005). Similarly, deforesta-
tion can be reduced by proper management of forest. For the management of forest, an effective strat-
egy should be developed to harmonize conservation priorities and development goals i.e. by including
native people in decision making procedures regarding utilization and conservation of forest resources
(Chakravarty et al., 2008). Similarly, for the efficient utilization of renewable energy, regular employment
of maintainers and operators for each installed renewable energy plant should be ensured. In addition,
Transparency in funding mechanisms of governmental procedures must be ensured, so that urban sprawl
can be reduced. Population explosion awareness programs in developing nations need to be conducted,
so that problem can be solved at grass root level. Some countries like China, had taken strong steps to
combat problems of overpopulation but the scheme (One child policy) has failed due to several reasons.
The scheme has encouraged people for increasing incidents of feticides, tending to gender inequality. A
large mass of population is now entered in an old age and only a small proportion of young generation
is there to support economic growth of country. Thus any scheme must be viewed with its possible pros
and cons, before implementation.
FUTURE RESEARCH DIRECTIONS
Demographic structure of different countries needs to be evaluated and the reasons behind the inverted
demographic pyramid should be assessed for each country. In addition, research needs to be conducted
on the effective ways to maintain impartial sharing of resources, so that carrying capacity of ecosystem
could be increased. Effective ways for awareness of people about programs related to family planning
must be determined and implemented.
Overpopulation has posed severe threat to environment with regard to deforestation, ecosystem degrada-
tion, climate change and adverse impact of human welfare. Several measures were adopted by developed
and developing nations in order to reduce the damage caused by overpopulation. These measures proved
inefficient to curb population growth, as were associated with some serious drawbacks. Therefore, ef-
fective awareness programs about population control, education in rural regions and impartial sharing
of resources must be ensured, so that population explosion could be controlled.
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KEY TERMS AND DEFINITIONS
Mortality rate: It denotes the death of individuals per unit time.
Natality rate: It represents the birth of individuals per female per unit time.
Red tapism: It denotes the requirement of excessive paperwork for any work, that usually prevent
or delay decision making process in bureaucracy.