Population and Environment Essay ⋆ Environment Essay Examples ⋆ EssayEmpire

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As of mid -2006 , the earth’s human population stood at approximately 6.48 billion. In 1 c.E., it is estimated that the global population was between 250-300 million. Humans reached the first billion by about 1804; the second by 1927. The world population hit five billion around 1987, and six billion in 1999. This means that an estimated six percent of people ever born on earth were alive in 2002. The length of time it took to add an additional billion people to the planet shrank dramatically. Whereas it once took millennia to add a billion people, that number was added in just 12 years. The human population is expected to continue to grow for the next 70 years, peaking at 9.22 billion around 2075. At least seven more decades of growth are forecast, mainly because the average person is living longer, and because so many potential parents are already born, also called “population momentum.”

Many people consider this inexorable rise in human numbers to be cause for alarm and immediate action to slow population growth. However, the rate at which new people are added to the planet has actually been decreasing for the last several decades. This rate of natural increase (RNI) is determined by the difference between birth and death rates. This rate peaked between 1965 and 1970, when the human population grew at over two percent per year-an astronomical figure unprecedented in human history. Since then, the gap between birth and death rates has slowly been closing; between 2000 and 2005, the global population grew by only 1.22 percent, and the rate continues to decline. This slowdown usually receives less popular attention-and is often confused with-the fact that human populations will continue to rise for the next 70 years or so.

The main reason for this slowdown has been a dramatic drop in fertility rates worldwide. The total number of children that the average woman is likely to have in her lifetime has been declining for several decades, and has done so much more quickly than most experts expected. Between 1950 and 1955, women on average had five children. By 2000-05, the global average had fallen to 2.7; in 2000, 42 percent of humanity lived in countries that had already achieved fertility below the replacement level of 2.1. This ongoing decline in fertility rates worldwide has been described as the biggest revolution in human population history.

There are multiple reasons for this fertility transition. Although it has varied in pace and magnitude by geographical region, a set of intertwined factors are generally recognized to be globally influential. These include: improved access to contraceptives, health care improvements that greatly enhance child survival, women’s greater access to education and work outside the home, a widespread shift from rural to urban livelihoods, postponement of marriage, and reduced cultural and religious pressures for large families. In the vast majority of cases, fertility declines reflect women’s desires to have fewer children. Only in rare cases has fertility reduction involved coercive practices, as, for example, with China’s one-child policy or certain reproductive programs in India.

Fertility decline is the single most important factor for understanding why global population growth is slowing. But mortality rates are beginning to contribute to this slowdown too. Because women have been having fewer children than in the past, the cumulative effect is that the global population is slowly becoming older as children comprise a smaller portion of the overall total. Today, the median age is 26; by 2010, it is estimated to be 44 years. Thus, even as life expectancies continue to rise, the aging of the population will result in higher death rates. As the decline in fertility continues, mortality rates are expected to creep upward.

When the two rates intersect-which is projected to occur by 2075-then the population will stabilize. These estimates are based on recent calculations by the United Nations Population Division, and they represent the most informed answer to date on the perennial question of how large the human population will become.

The Demographic Divide

Demographers commonly divide the world into two major regions: more developed (comprising North America, Europe, Australia, New Zealand, and Japan) and less developed (comprising the remainder). These are contested terms-sometimes affluent and poor are preferred. By this categorization, eight out of 10 people on earth currently live in less developed countries, which is why some observers argue they should collectively be known as majority world. China and India, whose status as less developed is currently a matter of debate, are the world’s two largest countries, with populations estimated at 1.3 billion and 1.1 billion, respectively, in 2005. Together, they account for almost half of the developing world, and 37 percent of the planet’s human population.

In 1950 about 29 percent of world population lived in more developed nations, with 21.7 percent in Europe alone. At that time, Africa’s share of world population was only 8.8 percent. These proportions have since changed dramatically as countries have experienced very different birth, death, and migration rates. For example, European women had on average 1.4 children in 2005-well below replacement-level fertility. The region is experiencing negative population growth. In contrast, the average woman in Africa had 5.1 children in 2005-the highest regional rate in the world-and rates of natural increase average 2.3 percent. As a result of these disparities, Africa held 14 percent of the world’s population in 2005, while Europe’s share dwindled to 11.2 percent.

The differences in demographic structure between these two regions exemplify what is known as the demographic divide, resulting in the separation of demographic issues into two distinct camps with very different attitudes and policy approaches. In Africa, for example, high birth rates mean that populations are young, with some 42 percent of the total population under age 15. Most governments consider their birth rates to be too high, and they may wish to prioritize investments in family planning programs, maternal and child health, and educational opportunities for girls in order to reduce fertility. At the same time, however, these governments face rising mortality rates and declining life expectancies due to HIV/AIDS. This devastating epidemic has in many cases drastically reduced the number of adults able to care for children, and diverted scarce health funds toward HIV/AIDS treatment and prevention.

In Europe, by contrast, the population concerns are far different. Extremely low fertility rates have led some observers to talk about a birth dearth. As populations age and individuals live longer, there is also much social angst about who will care for the elderly. In many cases, governments are reluctant to deal with the thorny social issue of maintaining or increasing their current population size through immigration, and are instead creating incentives to encourage couples to have more children.

The Population-Environment Debate

Whether the growing human population is inherently good or bad for the global environment is one of the most hotly debated issues in science. On one side of the debate are those that see human population numbers, and our rapid recent growth, as the most significant cause of environmental and humanitarian crises. The most famous advocate of this view was Thomas Malthus (1766-1834), an English pastor and economist. In a famous essay first published in 1798, Malthus argued that food supplies grow more slowly than do human populations, and he predicted that without the population checks of disease, death, or delayed marriage, population growth would outstrip food supplies and lead to hunger and misery.

In 1972 a group of scientists known as the Club of Rome recast Malthus’s main arguments in ecological terms. They and contemporary neo-Malthusians argue that human populations are growing faster than our ability to support ourselves from finite natural resources such as soil, water, and forestlands. They argue that we will soon exceed, if we haven’t already, our limits to growth, or the earth’s carrying capacity. The single most important way to prevent further environmental devastation and widespread human misery, they say, is to control the runaway population-to reduce human numbers as quickly as possible. Because they emphasize sheer numbers and densities of peoples in given areas, neo-Malthusians typically focus their attention on less developed countries, where large numbers of people, environmental degradation, and hunger often visibly coexist. To redress such problems, neoMalthusians advocate policies that prioritize fertility reduction through family planning, enforced control on resource use, and the setting aside of biodiverse areas as off-limits to resource users.

On the other side of the debate are those that feel that the number and density of people-at the global or regional level-is not the principal factor for understanding patterns of use, management, or degradation of the natural environment. They argue that the number of people that can be supported by natural resources depends very much on how humans choose to use, trade, and govern those resources; in effect, resources may be finite, but humanity’s ingenuity to find better and more efficient ways to harness and distribute those resources is not.

The Danish economist Ester Boserup (1910-99) is famous for her refutation of Malthus by showing how, throughout human history, growing numbers of people in rural areas stimulated the invention and adoption of more labor-intensive farming methods that allowed for higher yields. In other words, human populations have typically adapted their farming techniques to accommodate their growing populations. The academic Julian Simon (1932-98) also argued that people could be the solution to resource scarcity and environmental problems because of our ability to innovate ways to better use resources.

Recent field studies have also called into question neo-Malthusian explanations for such environmental problems as deforestation, soil erosion, desertification, and overfishing. Researchers repeatedly find very little direct evidence that such processes are the direct result of the number or density of local resource users. Rather, they show that these problems typically arise under specific political, historical, and economic circumstances. They find, for example, that when local users have a long-term stake in the management decisions affecting resources, then forests, wildlife, and biodiversity in general can thrive even at very high human densities.

Most significantly, critics of neo-Malthusian views argue that simple cause-and-effect models of overpopulation and environmental degradation ignore the profound interconnections between people, resources, and capital in the globalized world. They point out, for example, that the colonization of some countries by others has left a legacy of marginalization and inequitable resource distribution whereby peasants starve on tiny plots of marginal land while vast tracts of rich soil are controlled by multinational companies and devoted to the cultivation of export-oriented luxury foods such as coffee. This example shows that there are complex historical reasons for hunger and resource degradation that are largely unrelated to a country’s populationto-resource ratio.

An Emerging Consensus

Over the past decade or so, the consensus is emerging that human population numbers on their own are insufficient for understanding the human impact on the global biosphere. The equation I = PAT was proposed by ecologist Paul Ehrlich to reflect the fact that human environmental Impact was the product of Population, Affluence (usually measured as income per capita), and the Technologies used to meet everyday needs. Thus the impact of a few wealthy people living in amenities-rich urban luxury would have the same impact as many more people eking out a rural living with their own labor. But the equation still suffers from the misconception that specific environmental impacts are the direct product of characteristics of the local population.

The crisis of global warming helps frame these issues more holistically, and to focus particularly on the consumption side of the population-environment issue. For example, the United States comprises less than five percent of the world’s population, but is currently estimated to contribute some 33 percent of human-produced greenhouse gases into the earth’s atmosphere. Yet global warming-like most environmental problems-is not inevitable. There are technologies and skills to greatly reduce the reliance on fossil fuels. But economic momentum, political inaction, and everyday consumption choices have to date prevented many from meaningfully addressing this crisis. Doing so in a serious way means making tough choices about where to live (high density cities or sprawling subdivisions), what to eat (locally grown food or exotic imports), the types of technologies to choose (solar panels or coal-fired power plants), where to take vacations, and what clothes to buy.

To reflect the need to more closely examine the role of consumption in environmental problems, the New York-based Population Reference Bureau (which publishes an annual report compiling data on all countries’ population trends), has now included information on countries’ energy use per capita, as measured by kilograms of oil equivalent. By this metric, the average person in developing nations uses only 20 percent of what the average person in more developed nations does. Put another way: with 80 percent of the world’s population, the residents of less developed countries used, collectively, only 44 percent of the energy consumed annually.

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