Population Growth Rates example essay topic

Living Within Constraints Constraints on the Expansion of the Global Food Supply In the early ages people were hunters, or predators; they had to survive by killing other species. Although predators are supposed to be the strongest in the food chain, people were vulnerable because they had to depend on the same species below them. Our senses were not developed as well either; hearing, smelling, eye sight were and still are not as good as of those below us. We can't kill with our teeth or nails, like some alligators could. So after 4 ice ages, only 25,000 people were left.

That's when they realized that they had to change their loosing strategies and that's when they came up with Subsistence Agriculture. People domesticated animals, plants, and according to the number of the population today, we are doing real well. The world population grew slowly over much of the historic past; it was not until after 1900 that growth accelerated. The 1992 population was 5.5 billion.

Now the world population is increasing at about 1.7% yr, corresponding to a doubling time of 40 years. In the early 1960's, most nations were self-sufficient in food; now only a few are. Except for parts of Africa, production exceeded population growth throughout the world. Per capita production has now slowed and appears to be declining. In line with recent studies, we estimate that with the world population at 5.5 billion, food production is adequate to feed 7 billion people a vegetarian diet, with ideal distribution and no grain fed to livestock. Yet possibly as many as two billion people are now living in poverty, and over 1 billion in 'utter poverty' live with hunger.

Inadequate distribution of food is a substantial contributing factor to this current situation. Less than one half of the world's land area is suitable for agriculture, including grazing. Nearly all of the world's productive land, flat and with water, is already exploited. Most of the unexploited land is either too steep, too wet, too dry, or too cold for agriculture. Water Shortages: Pressures from growing population have strained water resources in many areas of the world.

Worldwide, 214 river or lake basins, containing 40% of the world's population, now compete for water. If we improve conservation of water, it would enhance rain fed and irrigated crop yields. A major difficulty arises simply from the rate with which food supplies would have to be expanded to pace or to exceed population growth rates in those countries experiencing high growth rates. In order to stay even with population growth it will be necessary to expand food supplies, globally, by the rate of population increase. For many countries the rate of population expansion is in the range 2-3% per year. If the historical record is any guide, no nation with a population growth rate above 2% yr has much hope of improving its per capita supply of food unless it receives very substantial external aid and support.

Of course these rates of increase for both population and food production, if achieved, cannot be sustained indefinitely. So what do we do? Projections of future production depend on a host of variables most of which are uncertain. As an alternative we consider three scenarios, for the period to the year 2050.1) Business As Usual The first assumes a continuation of present trends, patterns, and activities. This is referred to as BAU, Business- As- Usual.

Population is assumed to follow the UN medium projection leading to about 10 billion people by 2050, soil erosion continues to degrade land productivity. The consequences of greenhouse effect and of ultraviolet injury are ignored, and the developed world does not provide more aid to the developing world than at present. In general, it appears that Africa, China and India will face severe problems in expanding food supplies in the coming decades. The US appears to have the potential of generating food surpluses for some years, a potential that it shares with parts of Europe, including Eastern Europe, Canada, and possibly other regions. The longer-term prospects are unknown in view of difficulties which may appear later.

2) Pessimistic Scenario It adopts most of the assumptions in BAU, but includes several other factors which may decrease the rate of grain production in the years ahead. If the population growth rate continues only slightly lower than it is today to the year 2050, the world population will rise to about 13 billion, more than double the present population. The grain production in 2050 would increase only 30% from 1991, which means that per capita production would be down over 40%. There is, in this scenario, little hope of providing adequate food for the majority of humanity by the middle or later decades of the period we consider. 3) Optimistic Scenario Assumes rapid population growth stabilization with a 2050 population of 7.8 billion, significant expansion of energy-intensive agriculture and improved soil and water conservation with some reclamation of now-abandoned land. The developed countries would have to help finance these changes and also provide technology to the developing nations.

At the same time, with diet shifts in the developed world, the 2050 population of 7.8 billion might be fed an adequate diet. A Question of Direction: In what direction do we move to achieve the sort of world we want? There are two options offered by different sectors of society: A. Economic Expansion Proponents argue that people express their will through how they spend their money. Free markets will shape our future through supply and demand. The more money that changes hands, the better it is. B. Sustainability Looks into the future with concern for generations yet unborn. Ecological laws of resource availability and the ability of the biosphere to absorb the waste are respected.

The purpose is to maintain healthy secure livelihoods for all and other benefits of being human on a fine planet. If we want the generations to have a good future, we have to choose sustainability. At the same time we have to live within our means; our means, however, are the constraints of sustainability. SUSTAINABILITY: Activities are sustainable when they: a. Use materials in continuous cycles Within the limited stock of materials, any substances needed regularly must over time be used again and again. The cycles that bring the needed materials back for reuse must either occur naturally, like the cycles of water and carbon, or they must be maintained through recycling program, like paper. b.

Use continuously reliable sources of energy We are consuming supplies of coal and oil at the faster rate than they are created. This leaves heat from the Earth's core, tides, the sun and the wind. These power sources are abundant and have little or no negative environmental impacts. c. Come mainly from the qualities of being human (i.e. creativity, communication, coordination, appreciation, and spiritual and intellectual development). Once we have secured the food and shelter necessary for healthy life, worlds of opportunity open up for personal growth and satisfaction. The three "L's": Learning, Love and Laughter, as well as the arts, music, dance, sport, and appreciation of the universe within and around our selves, can make life worthwhile.

They can provide pleasure, purpose and meaning to our lives without harming the Earth. Activities are not sustainable when they: a. Require continual inputs of non-renewable resources Non-renewable resources are resources available only in limited quantity (ex. Metals, coal and oil). If our way of life requires that more and more of these materials be extracted, we will eventually run out. Therefore, dependency on more at this point would be disastrous. b.

Use renewable resources faster than their rate of renewal Some samples would be fish stocks, forests, ground water and soil fertility. As long as the rate at which they are used is not greater than the rate at which they grow or accumulate, the situation can remain viable. If the rate of use exceeds the renewal, the stock will become depleted and the problems will follow. c. Cause cumulative degradation of the environment When we create waste, which nature cannot handle, or which cannot be absorbed as fast as we create it, pollution builds up, causing the problems which become more and more serious as the activity continues. Small amounts of toxic material, after being absorbed by tiny materials, can accumulate in the flesh of the creatures that eat them. (ex. Fish).

And then you can imagine what happens when we eat fish ourselves. d. Require resources in quantities that undermine other people's well-being Some groups of people take unfair advantage of others. Inequality leads to social strife and armed conflict. Moreover, the people at the bottom of the pyramid are often forced by desperation to degrade the environment around them for day-to-day survival. The degradation of their territories not only makes life worse for them, but it also undermines the global system which provide for those at the tom of the pyramid as well as for those below. (ex. India) e.

Lead to the extinction of other life forms The web of life is mutually supporting and it is weakened with each life form lost. If we destroy the other forms of life, we undermine our own existence as the part of the global ecosystem. (Ex. With the loss of species we also lose genetic possibilities of fighting disease, in people and in food crops. ).