Impact of Population

IMPACT ON FOOD RESOURCES

• More than 99 per cent of the world's food supply comes from the land, while less than 1 per cent is from oceans and other aquatic habitats. The continued production of an adequate food supply is directly dependent on ample fertile land, fresh water, energy, plus the maintenance of biodiversity. As the human population grows, the requirements for these resources also grow. Even if these resources are never depleted, on a per capita basis they will decline significantly because they must be divided among more people.
• At present, fertile crop land, is being lost at an alarming rate. Nearly one-third of the world's cropland (1.5 billion hectares) has been abandoned during the past 40 years because erosion has made it unproductive. Solving erosion losses is a long-term problem: it takes 500 years to form 25 mm of soil under agricultural conditions.
• Most replacement of eroded agricultural land is now coming from marginal and forest land. The pressure for agricultural land accounts for 60 to 80 percent of the world's deforestation. Despite such land replacement strategies, world cropland per capita has been declining and is now only 0.27 ha per capita. The shortage of productive cropland combined with decreasing land productivity is, in part, the cause of current food shortages and associated human malnutrition.
• According to the World Bank and the UN, from 1 to 2 billion humans are now malnourished. This is the largest number of hungry humans ever recorded in history. Based on current rates of increase, the world population is projected to double from roughly 6 billion to more than 12 billion in less than 50 years. As the world population expands, the food problem will become increasingly severe, conceivably with the numbers of malnourished reaching 3 billion.
• Most countries, to some extent, are now dependent on food imports, most of which are surpluses from countries with a relatively lower population and practice intensive agriculture. For instance, just 6 countries - the US, Canada, France, Australia, Argentina and Thailand - supply 90% of grain exports. If, as projected, the U.S. population doubles in the next 60 years, then its cereal and other food resources would have to be used domestically to feed 520 million hungry Americans. Then the U.S. would cease to be a food exporting country. In the future, when exporting nations must keep surpluses at home, Egypt, Jordan, and countless other countries in Africa and Asia will be without the food imports that now help them survive.
• According to a 2007 article from the BBC, scientists at Columbia University have theorized that in the future, densely populated cities such as Mexico City, Los Angeles, and New York City, which are the largest in North America, may use vertical farming to grow food on each floor of 30-story skyscrapers.

IMPACT ON WATER RESOURCES

After food the most important requirement for man’s survival is water. Most of the water available to us is not fresh water, therefore is unfit for consumption or use in agriculture without being processed. Most of the available fresh water is locked in the form of ice sheets and glaciers. The rest which is in the form of lakes, rivers and from the underground water table is too little to fulfil all the requirements for domestic, industrial and agricultural use. As the population increases, the stress on water resources mounts, and along with the problem of global warming that causes changes in rainfall patterns, the water scarcity has become a major problems in most countries. So much so that there are fears that the Third World War will be a result of a tug-of-war for water resources.

• Fresh water supplies, on which agriculture depends, are running low worldwide. This water crisis is only expected to worsen as the population increases.
• Water is critical for all crops which require and transpire massive amounts of water during the growing season. In total, agricultural production consumes more fresh water than any other human activity. Specifically, about 87 per cent of the world's fresh water is consumed or used up by agriculture and, thus, is not recoverable.
• Competition for water resources among individuals, regions, and countries and associated human activities is already occurring with the current world population.
• About 40 percent of the world's people live in regions that directly compete for shared water resources. In China where more than 300 cities already are short of water, these shortages are intensifying.
• Worldwide, water shortages are reflected in the per capita decline in irrigation used for food production in all regions of the world during the past twenty years. Water resources, critical for irrigation, are under great stress as populous cities, states, and countries require and withdraw more water from rivers, lakes, and aquifers every year.
• A major threat to maintaining future water supplies is the continuing over-draft of surface and ground water resources.
• Diseases associated with water rob people of health, nutrients, and livelihood. This problem is most serious in developing countries. For example, about 90 per cent of the diseases occurring in developing countries result from a lack of clean water.
• The number of people living in urban areas is doubling every 10 to 20 years, creating major environmental problems, including water and air pollution and increased disease and food shortages.
• There are water deficits and rapid depletion of the water table in scores of countries due to widespread over drafting beyond sustainable yields.
• However, deriving freshwater from desalination of salt water, although very energy-intensive process, is a possible solution.
• A number of nuclear powered desalination plants exist, Some argue that there are billions of years of nuclear fuel available, but the high costs of desalination, especially for poor third world countries, make impractical the transport of large amounts of desalinated seawater to interiors of large countries, and the "lethal by product of saline brine that is a major cause of marine pollution when dumped back into the oceans at high temperatures."

IMPACT ON LAND RESOURCES

Land is the most important resources available to mankind, for without it there would be no food, water or shelter. As the population increases there is more need for land, not only for shelter, but also to grow more food, build hospitals, entertainment complexes etc. The impact on land resources due to population explosion are:

• World Resources Institute states that "Agricultural conversion to croplands and managed pastures has affected some 3.3 billion hectares — roughly 26 percent of the land area. All totalled, agriculture has displaced one-third of temperate and tropical forests and one-quarter of natural grasslands."
• Energy development may also require large areas, like for hydroelectric dams. Usable land may become less useful through salinization, deforestation, desertification, erosion, and urban sprawl.
• Global warming may cause flooding of many of the most productive agricultural areas. Thus, available useful land may become a limiting factor. By most estimates, at least half of cultivable land is already being farmed, and there are concerns that the remaining reserves (most of which is forest land) are greatly overestimated.
• Some claim that not all arable land will remain productive if used for agriculture, as they argue that some marginal land can only be made to produce food by unsustainable practices like slash-and-burn agriculture. Even with the modern techniques of agriculture, the sustainability of production is in question.
• Some countries, such as the United Arab Emirates and particularly the Emirate of Dubai have constructed large artificial islands, or have created large dam and dike systems, like the Netherlands, which reclaim land from the water to increase their total land area.
• The space taken by a human being itself is not a problem. It has been noted by a number of thinkers who deny that overpopulation is a problem - like noted philosopher Justin West - that the entire population of the world could live in Texas (or a land mass the size of Texas), assuming, of course, single floor houses, as well as no requirements for public spaces such as roads, schools, hospitals, separate commercial or industrial buildings, or recreational space.  Compacted this way, the rest of North America, and all of South America, Europe, Asia, Africa, Australia and Antarctica would be left vacant of human beings and open to farming. Also questionable is the meaning of "could live", with an average space between two people of just over 100 feet (30 m) - overcrowding will lead to a host of major social problems.

IMPACT ON ENERGY RESOURCES

• Fossil energy is a prime resource used for food production. Nearly 80 per cent of the world's fossil energy used each year is used by the developed countries. The intensive farming technologies of developed countries use massive amounts of fossil energy for fertilizers, pesticides, irrigation, and for machines as a substitute for human labour. In developing countries, fossil energy has been used primarily for fertilizers and irrigation to help maintain yields rather than to reduce human labour inputs.
• Because fossil energy is a finite resource, its depletion accelerates as population needs for food and services escalate. As supplies of fossil energy dwindle, the cost of fuel increases everywhere. The impact of this is already a serious problem for developing countries where the high price of imported fossil fuel makes it difficult, if not impossible, for poor farmers to power irrigation and provide for their other agricultural needs. Worldwide, per capita supplies of fossil energy show a significant decline.
• In general, developing countries have been relying heavily on fossil energy, especially for fertilizers and irrigation to augment their food supply. The current decline in per capita use of fossil energy, caused by the gradual decline in oil supplies and their relatively high prices, is generating direct competition between developed and developing countries for fossil energy resources.
• Population optimists have also been criticized for failing to account for future shortages in fossil fuels, currently used for fertilizer and transportation for modern agriculture. They counter that there will be enough fossil fuels until suitable replacement technologies have been developed, for example hydrogen in a hydrogen economy.
• The Earth has enough uranium to provide humans with all of their electricity needs until the sun blows up in 5 billion years, assuming that we develop large scale breeder reactors.
• There has also been increasing development in extracting renewable energy, such as from solar, wind, and tidal energy. If used on a wide scale, these could theoretically fulfil most, if not all, of the energy needs currently being filled by non-renewable resources. Most renewable energy forms rely on an oil-based economy to produce, i.e. you can't make a wind turbine without the oil run machinery to begin with, making the whole process moot. However, it should be noted that some of these renewable resources also have ecological footprints, though they may be different or smaller than some non-renewable resources.

IMPACT ON THE ENVIRONMENT

Overpopulation has had a major impact on the environment of Earth starting at least as early as the 20th century. There are indirect economic consequences of this environmental degradation in the form of ecosystem services attrition.

• According to the Wikipedia dictionary, 'Overpopulation indicates a scenario in which the population of a living species exceeds the carrying capacity of its ecological niche.
• In common parlance, the term usually refers to the relationship between the human population and its environment (the planet Earth).
• Though the birth rate has fallen in some economically advanced countries, it has increased alarmingly in other countries, leading to increased pressure on land and other resources.
• Since human habitat and livelihood are closely interconnected with the surrounding ecosystem, increased pressure from population can cause irreversible damage to fragile ecosystems. Significantly, in some cases, technological advances of developed countries lead to more exploitation of natural resource than the so-called developing countries.
• Beyond the scientifically verifiable harm to the environment, some assert the moral right of other species to simply exist rather than become extinct. Says environmental author Jeremy Rifkin, "our burgeoning population and urban way of life have been purchased at the expense of vast ecosystems and habitats. ... It's no accident that as we celebrate the urbanization of the world, we are quickly approaching another historic watershed: the disappearance of the wild."
• Says Peter Raven, former President of the American Association for the Advancement of Science, "Where do we stand in our efforts to achieve a sustainable world? Clearly, the past half century has been a traumatic one, as the collective impact of human numbers, affluence (consumption per individual) and our choices of technology continue to exploit rapidly an increasing proportion of the world's resources at an unsustainable rate. ... During a remarkably short period of time, we have lost a quarter of the world's topsoil and a fifth of its agricultural land, altered the composition of the atmosphere profoundly, and destroyed a major proportion of our forests and other natural habitats without replacing them. Worst of all, we have driven the rate of biological extinction, the permanent loss of species, up several hundred times beyond its historical levels, and are threatened with the loss of a majority of all species by the end of the 21st century."
• A 2001 United Nations report has postulated that, although human activity can be blamed for much of the environmental degradation in the last century, overpopulation is not a major cause, but rising per-capita production and consumption and the use of particular technologies used in such production are more likely major factors.
• Further, even in countries which have both large population growth and major ecological problems, it is not necessarily true that curbing the population growth will make a major contribution towards resolving all environmental problems.
• However, as developing countries with high populations become more industrialized, pollution and consumption will invariably increase.
• Technological advances during the last century led to low mortality rates and high birth rates across countries around the world. In addition to this, increased migration and concentration of population clusters in selected locations have put extreme pressure on the surrounding regions.
• Scientists are now predicting that unless we bring a healthy balance in the growth rate our environment may face irreversible damage that will jeopardize our future. According to a UN report, the world population is predicted to grow from 6.5 billion to 9.1 billion by 2050. Can you imagine the pressure this will put on our scarce resources?
• According to the Millennium Ecosystem Assessment, a four-year research effort by 1,360 of the world’s leading scientists commissioned to measure the actual value of natural resources to humans and the world, "The structure of the world’s ecosystems changed more rapidly in the second half of the twentieth century than at any time in recorded human history, and virtually all of Earth’s ecosystems have now been significantly transformed through human actions." "Ecosystem services, particularly food production, timber and fisheries, are important for employment and economic activity. Intensive use of ecosystems often produces the greatest short-term advantage, but excessive and unsustainable use can lead to losses in the long term. A country could cut its forests and deplete its fisheries, and this would show only as a positive gain to GDP, despite the loss of capital assets. If the full economic value of ecosystems were taken into account in decision-making, their degradation could be significantly slowed down or even reversed." The MA blames habitat loss and fragmentation for the continuing disappearance of species.
• So the problem is not simply population growth but finding the right balance between population growth and sustainable development.

REFERENCES

• IMPACT OF POPULATION GROWTH ON FOOD SUPPLIES AND ENVIRONMENT
  by David Pimentel, Xuewen Huang, Ana Cordova, and Marcia Pimentel.

Presented at AAAS Annual Meeting, Baltimore, MD, 9 February 1996
Submitted for publication to Population and Development Review, New York, NY, USA  (http://dieoff.org/page57.htm)

• http://www.panda.org/about_our_earth/teacher_resources/webfieldtrips/population_growth/

• http://knowledge.allianz.com/en/globalissues/demographic_change/population_growth/population_growth_malthus.html

• http://knowledge.allianz.com/en/globalissues/demographic_change/?utm_source=google&utm_medium=cpc&utm_term=population%20growth&utm_campaign=Allianz%20Knowledge%20-%20Demographic%20Change
  
• http://online.wsj.com/public/resources/documents/info-unbk0609-06.html
  
• http://www.wikipedia.org/