Mike Ko Personal Portfolio

 

Home-School Education
2001-2012
Hong Kong

University of Durham
Bachelor of Science
2014-2017
United Kingdom

University of Sussex

Master of Arts
2017-2018
United Kingdom



Writing - Original

Is Resource Scarcity due to Overpopulation?

 

                                       

 

                        The history of human expansion has been an astonishing one. More than ten thousand years ago, we were just one species of primates struggling to survive in a single continent. Then things changed when we utilized more and more resources from nature. We quickly developed the ability to support larger populations, eventually resulting in the current metropolises that cover many parts of the globe. Humans became one of the most successful animals (in terms of numbers) on the planet. All of that stems from our exploitation of resources, from wood for spears to metals for electronics. It improved our capability to sustain ourselves, thus allowing individuals to devote time to other tasks. We devised practices that improved various aspects of human life, from agriculture to medicine. That is why we can have a population of around seven billion people today.

                        From this point the picture is changing once again. In recent times it seems that nature’s resources are becoming scarce. Back in the past – whether it is a century ago or much, much farther – humans have pretty much consumed Earth’s resources with the assumption that they never run out. That is fine for previous, small populations with negligible consumption with respect to Earth’s supply. Yet it becomes folly when we apply that assumption to seven billion people. The Earth’s supply of matter, hence natural resources, does have a limit. If we keep on consuming without regard to this limit, we shall run short on many resources. In light of this obvious but often ignored predicament, some have proposed that Earth has more people than it can support. Our problem is that we have too many people all clamoring for limited resources. As each individual gets less, everybody suffers. This is the idea overpopulation.

Resource Scarcity from Overpopulation?

                        Overpopulation had an early beginning, before we had gigantic populations. The idea notably came up in 1798, from the English economist and clergyman Thomas Robert Malthus. In his book, An Essay on the Principle of Population (6th Edition, 1826), Malthus stated that poverty, vice and misery of society is caused by the “constant tendency in all animated life to increase beyond the nourishment prepared for it” {1}. People tend to reproduce more than they can feed themselves. Normally, such tendency is restrained by factors like an individuals’ concern of their inability to support offspring. Facing difficulty in obtaining sufficient nourishment amid constant food supply and increasing population, individuals might refrain from reproducing. This eventually reduces the population back to a sustainable size.

                        Yet if this social restraint fails, population growth shall outpace growth of necessities. People shall become “miserable” due to a lack of sustenance, which also induces crime and other immoral behavior. They shall become impoverished due to low wages from inflated labor supply. Such conditions eventually initiate natural population restraints, extreme examples being war and famine. These again decrease population to sustainable sizes with respect to food. Hence population is limited by sustenance available. This is what overpopulation refers to today: unrestrained reproduction that at unsustainable sizes shall eventually be forcibly reduced. However, in this age many resources are limiting factors rather than just food.

                        Of course, the mentioned principles of population are not unique to humans. In biology, ecosystems have a limit called the carrying capacity. This is the amount of a given species that the system’s resources can support. If the population exceeds the limit, lack of resource shall eventually reduce the population back to the limit. With limited resources, only a finite number of individuals can be sustained. This concept applies to all species, humans included.

                        Right now, it may seem that humans are pushing against those limits, especially if you consider the planet’s current state. In terms of the environment, many wild species are facing extinction due to habitat or resource loss, often due to human resource extraction or usage. Surging carbon dioxide emission from our part resulted in climate change. By some estimates, the planet shall warm by 1 to 4 °C per 100 years {2}. This may seem mild, but its rate is actually much quicker than previous cases of natural warming. Organisms may be unable to adapt quickly enough. Such developments can destabilize entire ecosystems and cause great damage to all life. From a social perspective, there are populations that still struggle just to survive. Famines still occur, and there are shortages of certain important resources like water and fish. All of these can reasonably be assumed to be caused by our burgeoning population.

                        So is this the whole story? Is overpopulation to blame for most of our problems, including resource scarcity, today? Are we really at the point where further population increase shall wreck the Earth and render it uninhabitable? Are our problems today the effects of the natural limits that Malthus mentioned? Must we limit our reproduction through birth control policies like those of China and India to save humanity? And are such measures ethical? Currently there is no consensus on the legitimacy of overpopulation. It is a challenging, ethically-sensitive issue that shall certainly be passionately debated for quite some time. Here I shall present my views on the relationship between overpopulation and resource scarcity. As we shall see, this relation may not be as straightforward as one may assume. We start by examining overpopulation in greater detail, beginning with its direct underlying cause: reproduction.

The Conditions for Overpopulation

                        Overpopulation is due to excessive reproduction by humans. So why do we reproduce in such a manner? One answer may be that our population will eventually decline to nothing if we did not. Yet such a scenario is highly unlikely today. Humans are now evidently quite adept at surviving, having an approximately seven billion population. At this stage, a reproduction rate that can sustain the population size shall suffice. Yet that is not the case at the present. Certain countries are still reproducing at rates that shall further increase our population. For example, total population of Africa is projected to more than double (145%) in the next 50 years {3}. So some populations still tend to reproduce vigorously, without regard to economic or other factors. Why do we do this so? It all goes back to the start of life.

                        If scientists’ theory is correct, life began as a single, replicating cell. From that cell, the common ancestor of life evolved, producing numerous descendants that include all existing life today. All of them exist because they survived to reproduce. When individuals of one generation die, the next generation keeps the wheel of life spinning. In that sense, all species (human or otherwise) do reproduce to maintain their population numbers, but not consciously. Rather, the urge to survive and reproduce is a behavioral mechanism that was set at life’s beginning. Life naturally reproduces continuously. As such, it is unsurprising if humans actually did reproduce right up to the planet’s limit. It is our natural behavior.

                        So all life on Earth, including humans, are caught in this never-ending race to survive and reproduce. From what we can see today, it seems humans have been rather successful in these two endeavors. Yet it was not always easy, as history has shown. From our age as hunter-gatherers to medieval times, to even as close to a few centuries ago, there existed many barriers to successful survival, hence reproduction. One notable factor is food. People must to eat to survive. Yet its production is potentially unstable, due to weather and other factors out of human control. When crops fail, famines ensue and populations can starve to death. Another example is disease. Outbreaks like Black Death in the 14th century have drastically reduced human population, hence their reproductive capacity. These two obvious examples are just the tip of the iceberg. Many other factors hinder human survival and reproduction, including meteorological, social, biological and geographic factors. Such factors restrained population growth in the past.

                        However, in the last century our population has steadily increased, and it is projected to continue for the rest of the century. What happened to the reproductive barriers? Obviously they still exist. What has changed, as most of us know today, is technology. Simply put, we effectively used resources to overcome the many barriers of human survival and reproduction. Large-scale agriculture has stabilized food supply so that most people rarely worry about famines now. Most infectious diseases can nowadays be controlled by medicine, significantly improving survival rates for many maladies. Because of these and many other improvements, people can easily survive till maturity, reproduce offspring, and enjoy longer lifespan. Data from the United Nations showed a 45.2% increase in world life expectancy at birth in the last 50 years {3}. Certainly these are beneficial improvements for society. Yet it is also here that the problems start, supporters of overpopulation shall argue.

                        When lifespan and reproductive rate increase, it results in greater resource demand than supply. As we have more people who live longer, we consume more food, water, shelter, and other necessities. Eventually people outnumber resource supply, and we have resource scarcity. Unchecked, the scenario predicted by Malthus shall become true (although with respect to all resources instead of food only). Entire populations shall suffer, war with each other, and die for resources. This is overpopulation, a result of ever-increasing population and insufficient resource.

                        We can compare this situation to a hypothetical experiment with bacteria in an airtight jar. A jar contains a colony of bacteria and periodically receives sugar. The bacteria consume the limited sugar imports, multiply, and progressively eat more before receiving the next batch. Eventually the jar’s sugar supply jar shall be exhausted before the next sugar batch arrives. If reproduction continues, the bacteria colony starves. Thus they shall die until the population returns to sustainable levels. Population exceeds available resources. Not an ideal scenario.

                        So here are the conditions for overpopulation: runaway population growth and a lack of resources. For the former, we know our population shall continue to increase for at least decades. Yet is the latter true as well? To determine whether growing populations are problematic, we must determine whether we are short on resources. In other words, do we have enough resources to sustain ourselves? It increasingly appears that we do not.

Scarcity of Fundamental Resources

                        The crucial resources for humans include Food, Water, and Energy. These have always been obtained from our environment. In recent decades, they (or some part of them) have become increasingly deficient. We shall begin with food.

                        Today around 38% of the Earth’s land is already devoted to farming {5}. The remaining parts are mostly unsuitable for agriculture, being desert, polar, mountainous, or urban regions. So there is not much room left for future agricultural expansion. As population continues to grow, it shall become increasingly difficult to farm enough food from existing land. Scarcity of arable land shall eventually lead to scarcity of food.

                        In addition to land shortage, society’s last wild food source is also being depleted. Many of the world’s fish stocks are now overfished. By the Food and Agriculture Organization’s 2005 estimates, 17% of the 441 fish stocks observed are now overexploited. This means that they are fished beyond the maximum sustainable level. 52% are fully exploited; these fish stocks are at maximum sustainable yield. 7% of fish stocks are depleted, which means that their yields are below historical amounts {4}. In other words, world fisheries are already hard-pressed to satiate the world’s appetite for fish. Even if population remains constant, increasing demand from existing populations (like emerging economies) shall further drain supplies. Now imagine coupling that increased demand with those due to further growing our population. This can adversely affect people whose livelihood depends on fish, either in terms of food or their careers. It also affect fish population themselves, reducing their future potential as a viable food plus damaging ecosystems.

                        While becoming deficient in food is troubling enough, food production itself also requires many resources. As population hence food demand increases, so shall farming. That means more resources are used for agriculture, which further drains those resources’ supply. One of these is our next scarce basic resource: water.

                        Although the Earth is covered in water, only a small, constant portion of it is fresh (3% {6}). Humans must use that small portion to fulfill their drinking, washing, farming, and other needs. Yet not everyone can get water of good quality. The WHO/UNICEF 2010 Joint Monitoring Programme report stated that 884 million people still cannot get improved drinking-water {7}. This essentially means they have no access to clean and sustainable water sources. Inaccessibility to clean water can have many causes, including pollution, bad infrastructure, and natural geographic distribution. These can potentially be solved by technology and better government investments. Yet these improvements are of little help when demand actually exceeds supply.

                        Today various countries – including Mexico, parts of India and many African countries – are already facing water scarcity {8}. The demand for water in these places exceeds supply. While the world certainly does not face a flow-blown crisis at the present, it is all set to worsen. As total population continues to increase, so shall total water consumption. Yet the Earth only has a constant amount of fresh water. Eventually rivers and underground aquifers shall deplete quicker than they can replenish, and droughts shall ensue. In addition, climate change is predicted to further decrease the amount of available water for consumption. By 2025, the UN estimates that 1.8 billion people shall live in regions with absolute water scarcity {8}. Water might be a fundamental resource, but it seems our population is outgrowing the Earth’s supply.

                        Equally important is energy in the form of electricity, which we mostly derive today from fossil fuels. These include coal, oil, and natural gases, which together supplies the energy that powers modern society. We use such fuels to power our cars, dwellings, industry, and nearly everything else. Yet fossil fuels are not permanent fixtures of nature. They are made when organic matter reacts underground to form combustible solids, liquids, or gases. Unfortunately, the time it takes to form appreciable amounts immensely exceeds the scale of human lifespan. Hence fossil fuels are essentially a limited commodity to humanity.

                        There are various estimates on when our fossil fuel productions shall peak. These are the so-called peak coal, peak oil, and peak gas. Once the peak is reached, production declines indefinitely. One estimate predicts peak oil by 2014, and that 90% of all oil shall be extracted by the 2050s {9}. This estimate already anticipates successive technology breakthroughs that improves yield. Another source estimates peak coal by 2025, which is cited as the best scenario {10}. For natural gases, an estimate places peak gas at 2020 {11}.

                        Note that such peak estimates can be highly variable, depending on the source. Regardless, it is certain that fossil fuel production shall peak eventually in the foreseeable future and drop. Demand increase due to growing population shall deplete our declining supply even quicker. Clearly our declining fossil fuel supply cannot support our future growing populations’ energy demand. Renewable energies, like wind or solar power, might be an alternative. Yet such technologies need more time to develop further before they can produce appreciable electricity. As such, society currently has no long-term sustainable resource for producing energy despite the increasing demand.

                        All this shows that humanity’s important resources, food, water and energy are insufficient, or soon will be. If these are lacking, society shall face a quite unpleasant future. In addition, finding resources is not the only problem for future societies. In many ways, our methods for extracting and using nature’s resources actually damage its ecosystems. Rivers become polluted, habitats are razed, food chains are disrupted, and various species goes extinct. All this ruins the environment, the place where humanity lives in. Plus, such human activity sometimes destroys the source of the same or other resources. In other words, humans are depleting resources and destroying their existing sources.

                        The final effect of all this shall be an inhospitable, resource-scarce world supporting even larger populations. Certainly this is not a sustainable model, both present and future. Yet it is also where society are headed is headed for. Society must find and stop the force that drives us to such a fate. So what is leading us to this potential disaster? Some are eyeing developing and least developed countries with growing populations as the culprits. Currently, certain developing countries in Africa and south-central Asia have the highest fertility rates {12}. As their populations grow, they increase resource consumption and make humanity and nature worse off.

                        So must we control these countries’ populations to curb excessive demand and stave off resource scarcity? Not necessarily. As we shall see, resource consumption is not always proportional to population size. To understand this, consider the following reasoning on consumption of energy, a resource that means everything today.

Resource Consumption is not necessarily proportional to Population

                        Imagine two people. One is a citizen of the United States of America, the other a tribal villager from Africa. Now project how much energy they use. The urban citizen, living in a modern environment, consumes fossil fuel for almost everything. These include vehicle fuel and electricity for electronics, lighting and appliances. In addition, the products he consumes – packs of biscuits, clothes, among others – are manufactured with energy too. The tribal villager, on the other hand, consumes close to no fossil fuel. He has no electronics, travels by foot, and probably burns scavenged materials for lighting at night. People from different places consume different amounts of resources.

                        Certainly not all Africans are tribesmen today; many have moved to cities, where electricity use is more prevalent. Similar trends also apply to other growing populations in Asian countries. Such migrations increase energy demand. However, these countries’ total energy consumption can still be quite modest when compared to developed countries. We can compare American energy consumption with that of developing countries or regions as an example. As of 2008, the United States’ total energy consumption is six times greater than African consumption {13}. Compared with India, the second most populous country on Earth, Americans consume five times as much. Hence we must not hastily blame countries with growing populations for our fossil fuel woes. They are not the ones who use the most of it.

                        Disproportion between population and consumption can also exist for necessities like food. This may seem puzzling for a basic resource: Surely people must eat enough to survive? Actually, that only happens in an ideal situation. The reality is that many people eat less than enough for a healthy living. A Food and Agriculture Organization report gives the following estimates for undernourishment in 2008: More than 235 million in Africa and 560 million in Asia {14}. Some people from these areas are even facing potential famine. A recent one just occurred in East Africa, starting from July 2011. Although countries may have growing populations, they can actually consume less food than expected relative to population.

                        Energy and food are two examples of disproportionate consumption relative to populations. Yet why is this so? One major reason for this disproportion is poverty. While many people in countries with growing populations have moved into cities, they are often quite poor. Many have a gross national income per capita of only $US 290 to $US 3,800 {12}. Economies of these countries are either just developing or have barely started at all. They have yet to grow into the high-consumption economies of developed countries. Their populations often have just enough to purchase necessities, sometimes not even that. Hence developing and least developed countries’ ability to consume resources is limited. To say that those with growing populations are straining our resource supply is inaccurate at best.

                        In contrast, we expect developed countries to have high resource consumption, despite having relatively smaller populations. The rationale for this assumption is again based on economic factors. Developed countries have advanced economies that greatly encourage consumption, permitted by relatively higher income. With this disposable income, people can buy various nonessentials goods. All of these goods require resources to be manufactured and sometimes to function. Also, developed countries’ urban environments require vast resources to be built and function. Electricity is required for most of its basic functions, including lighting and waterworks. Indeed, we saw that Americans alone consume more energy than Africans. As energy is required for manufacturing, commerce, and many other activities, it also reflects consumption of other resources. So consumption of other resources can be expected to greater for developed countries as well.

                        All in all, population is not the sole influence on a country’s resource consumption. Those countries whose populations are growing the most do not use the most. Hence overpopulation, at this stage, is not the driving cause for resource scarcity.  Furthermore, it is probably the wealthy developed countries (plus several rich, rising developing countries) who consume the most resources. Thus it is they, if anyone, who are causing resource scarcity. So what exactly causes people of developed countries to consume the most? The answer may lie in their lifestyle.

The Real Cause of Resource Scarcity: Lifestyle of Overconsumption

                        In society, many people hold the belief that material wealth equates to a good living. They consume extra (survival nonrelated) goods for supposedly better lives. Sensibility aside, the greater disposable incomes of developed countries’ populations certainly permit such extra consumption. Yet economic factors only act as a facilitating factor. The fundamental cause is that economic affluence encouraged lifestyles that constantly consume more than what is required. As long as they have the money, people living this lifestyle shall consume what they can afford.

                        This mentality for consumption probably existed for as long as humans have. Even as early, primitive groups, Homo sapiens consume natural resources. Demand depended on the supply from nature, and on how humans can devise uses for such resources. Those who can utilize resources for new purposes shall do so. Certainly our ancestors have never thought about the limits of the planet’s supply of resources.

                        The same pretty much occurs today, with modern humans utilizing various resources to power our modern society. However, technology has greatly expanded how we can utilize Earth’s resources. Various kinds of substances that most people do not even know are routinely used, like metals or organic compounds. Yet our current ideal lifestyle – namely with great material wealth – reflects our persistent ignorance of the planet’s limits. Now we are beginning to feel that limit, as resources scarcity starts to bite. We can probably blame the rich for this, and it is not simply an envious hatred.

                        The United Nations Population Fund stated in a report that 50 per cent of our carbon dioxide emissions were made by the richest 500 million people (around seven percent of total population) {15}. Carbon dioxide emissions are proportional to energy use. That means seven per cent of the population consumes roughly 50 per cent of total energy consumption. Energy is often used in conjunction with other resources. So it can be said that the few, wealthy people consumes many resources in general.

                        All of that is the result of the lifestyle of overconsumption. Of course, this over-consuming lifestyle did not emerge recently. More than a thousand years ago, the rich sought for silk, spices and other contemporary luxuries. Kings and emperors used enormous amounts of resources to build lavish palaces and other non-required goods. Although we do not have many kings and emperors now, we still have rich people. Today, demand for nonessentials have greatly expanded, be it smart-phones, jewelry, private yachts, or closets’ worth of shoes, among many others. They consume mostly because they can. And to a certain extent, even the middle class of the world have adopted the over-consuming mindset. They too, consume luxury, non-essential goods as much as they can comfortably afford to.

                        Such over-consuming lifestyle is now the root cause of resource scarcity. Apparently, the completely disproportional consumption it engenders is depleting the world’s resources. We face resource scarcity mainly because we ignored the Earth’s limitations, and consumed what we can get. Overconsumption, not overpopulation, is causing the various shortages in resources. Monetary affluence of various extents has lulled people into unrestrained consumption, and is leading humanity to imminent disaster. We must change this unsustainable lifestyle. Plus it must be made at a fundamental level.

                        Nearly all societies aspire to become economically powerful. Yet they do not give any thought to consumption levels once everyone becomes rich. The rich tend to over-consume, which eventually shall ruin the planet. Yet our current models of social development do not consider the Earth’s resources as limited. Hence society must find other ways to develop in a sustainable manner with respect to Earth’s resources.

                        This is not to say that we must revert to primitive lifestyles like those of our ancestors. Although it can certainly resolve resource scarcity, it is probably not the optimal lifestyle for humanity. Society is now too accustomed to the current lifestyle to make such radical changes anyway. However, if humanity continues to over-consume as we do now, eventually Earth’s finite resources shall be depleted. It does not matter if we can find several Earth’s worth of resources; all shall be spent by overconsumption.

Required Changes for a Sustainable Future

                        What is necessary is that society must recognize the facts. The Earth harbors limited resources. We cannot magically conjure steel or leather bags from empty space. We live in a closed system, the Earth. Our lifestyle of unrestrained consumption is unsustainable. If continued it shall drain resources and damage the Earth, creating an inhospitable environment for modern society. Hence a balance must be achieved between consumption and conservation of resources.

                        This shall be difficult, as people have aspired to be wealthy (materialistically and fiscally) and powerful for thousands of years. To ask people to place resource conservation before their personal goals is hard. Resource scarcity never was an apparent problem for modern society before. Many may refuse to acknowledge or confront it today, unwilling to forsake their existing lifestyle. They see no short-term ill consequences (or refuses to) from overconsumption. Yet when everyone adopts this mindset, resource scarcity results in the long-term, plus the suffering it creates.

                        Consuming less runs against traditional thinking, but it must be done for humanity to have a future. A first step towards this goal is to reduce waste in our everyday lives. Modern society uses resources in many inefficient ways. Go to a fast food restaurant chain and you get a dozen disposable items. Similarly, most commercial products come with elaborate packaging. Various industrial and manufacturing processes often produce unwanted and often harmful byproducts, most notably pollutants. Such products, just several among many, usually offers little to no benefit for society. If we want to curb our disproportional consumption, we can start by reducing waste and improving efficiency. Scientists are already aiming for this goal in green chemistry. They strive to make chemical reactions that minimize waste products and required input resources, while maximizing the desired product. If society can do so on a large scale, resources can be saved for better, practical use. It can certainly ease resource scarcity.

                        Yet such efforts are not enough to bring consumption to sustainable levels. To reign in disproportional consumption, we must eventually tackle its source: the lifestyle of overconsumption. Ideally, people must change their mindset and conventional wisdoms on resources. We must constantly keep the Earth’s limited resources in mind when making decisions. The lifestyle that endlessly pursues material wealth must stop. We must rationally question ourselves whether our consumptions are necessary. If possible, society shall monitor resource availability, prioritize consumption, and accordingly decide how much to consume. Consumption of low priority, notably luxury items (think of yachts and jewelry) are restrained when resources are scarce. Consumption primarily depends on actual need.

                        Such a model can certainly be sustainable, but society may be unwilling to accept this more restrictive lifestyle. Whether humanity can set aside our short-term wishes, and rationally prepare for the approaching adversities is doubtful. Humanity must be highly unified just for it to attempt in universally justifying and reduce consumption. Given the fragmented interests of the world’s nations, this is practically impossible. Yet this must be done if society is to peacefully and fairly adapt to the Earth’s limited resource. How the situation plays out as resource scarcity worsens shall be revealed with time.

                        Overpopulation is not the main cause of resource scarcity today because not everyone consumes equally. The problem is due to a portion of the population consuming resources in greatly disproportional amounts. Humanity must reduce such consumption and abandon the lifestyle of overconsumption. Society must focus on the right issue to tackle, and then find a just, collaborative solution. Although nearly impossibly difficult, nothing less is required for the peaceful survival of humans as a species.


                                                                                                                                                                  Mike Ko
                                                                                                                                                                  ( 4,802 words )

            Sources:

 

    1. "An Essay on the Principle of Population" by Thomas R. Malthus, 1826; Library of Economics and Liberty. Retrieved September 11, 2011 from the World Wide Web: http://www.econlib.org/library/Malthus/malPlong.html
    2. “The Last Great Global Warming” by Lee R. Kump; Scientific American, July 2011
    3. “World Population Prospects: The 2010 Revision”; Population Division of the Department of Economic and Social Affairs of the United Nations Secretariat
    4. “Review of the State of World Marine Resources”; Food and Agriculture Organization of the United Nations, 2005
    5. “Can We feed the World and Sustain the Planet?” by Jonathan A. Foley; Scientific American, November 2011
    6. United States Geological Survey. Retrieved November 23, 2011 from the World Wide Web: http://ga.water.usgs.gov/edu/waterdistribution.htm
    7. “Progress on Sanitation and Drinking-Water, 2010 update”; WHO/UNICEF Joint Monitoring Programme for Water Supply and Sanitation
    8. “Coping with Water Scarcity: Challenge of the Twenty-first Century”; World Water Day 2007, UN Water
    9. “How Much is Left?” by Michael Moyer; Scientific American, September 2010
    10. “Coal: Resources and Future Production”; Energy Watch Group, March 2007
    11. “Global Oil and Gas Depletion: an Overview”, by Roger W. Bentley; Energy Policy, 2002
    12. Population Reference Bureau: www.prb.org; IBGE ( Brazil )
    13. U.S. Energy Information Administration, International Energy Statistics database (as of March 2011). Retrieved October 9th, 2011 from the World Wide Web: www.eia.gov/ies
    14. “The State of Food Insecurity in the World 2011: How does international price volatility affect domestic economies and food security?”; Food and Agricultural Organization of the United Nations
    15. “State of World Population 2011: People and Possibilities in a World of 7 Billion”; United Nations Population Fund

 

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