Title: Will the earth's land and water resources be sufficient for future populations?

POPLINE Document Number: 079457

Author(s):

Revelle R

Source citation:

In: The population debate: dimensions and perspectives. Papers of the World Population Conference, Bucharest, 1974. Volume II, compiled by United Nations. Department of Economic and Social Affairs. New York, New York, United Nations, 1975. :3-14. (Population Studies No. 57|ST/ESA/SER.A/57)

Abstract:

One hectare of corn planted with technology available to an Iowa farmer can provide enough food energy for 24 human beings, i.e., 260 kg or about 570 lbs of corn/year/person. World cultivation of land is 1.4 billion hectares to provide food, fiber, and agriculture products for 3.5 billion people in 1974. Actual cultivated land requirements are nearly 10 times this calculated minimum. The reasons are harvests come from only 50-66% of the total cultivated land. 10% of land is devoted to nonfood crops and another fraction is devoted to livestock. 10-20% of crops are destroyed by pests. Agricultural technology is not used evenly throughout the world, i.e., yields are just over a ton/per cropped hectare in Pakistan or India. Discussion focuses on potential arable land, potential gross cropped area, potential water supply, and obstacles to the potential expansion of cultivated areas. The obstacles are identified as the poor quality of potentially available arable land, the large capital investment required, uneven distribution of population and potentially arable land, and the necessity to improve the level of agricultural technology. The approximately 2.43 billion of net potential arable land and the 4.06 billion hectares of gross cropped land are estimated with currently available technology to feed 38-48 billion people, or 10-13 times the current world population in 1974. The potential, however, is quite different from the reality. The Food and Agriculture Organization has recommended that less developed countries increase both multiple cropping and total cultivated area by 1985 in order to keep pace with population growth. The assumption is that all available river water available for human use could be diverted for irrigation agriculture. Dams and tube wells may be required. Conflicts may occur in land and water use. Examples of agricultural productivity are given in India, Bangladesh, and sub-Saharan Africa. Modernization is required in order to maintain carrying capacity for all human beings. Expansion into sensitive environments will most likely entail ecological destruction. Declines in population growth are dependent on increases in income and its equal distribution.

Keywords:

Global
Philosophical Overview
Land Supply
Water Supply
Carrying Capacity
Food Supply
Technology
Soil Degradation
Population Pressure
Natural Resources
Environment
Economic Factors
Environmental Degradation