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 cant kill with our teeth or nails, like some alligators could. So after 4 ice ages, only 25,000 people were left. Thats when they realized that they had to change their loosing strategies and thats 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 1960s, 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 worlds land area is suitable for agriculture, including grazing. Nearly all of the worlds 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 worlds population, now compete for water. If we improve conservation of water, it would enhance rainfed 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.