Tài liệu tham khảo về Anh Văn | The population of the world has increased more in modern times than in all other ages of history combined. World population totaled about 500 million in 1650. It doubled in the period from 1650 to 1850. Today the population is more than five billion. Estimates based on research by the United Nations indicate that it will be more than double in the twenty-five years between 1975 and the year 2000, reaching seven billion by the turn of the century. No one knows the limits of population that the earth can support. Thomas Malthus, an English economist, developed a theory that became widely accepted in the nineteenth century. he suggested that because world population tended to increase more rapidly than the food supply, a continual strain was exerted upon available resources. Malthus cited wars, famines, epidemics, and other disasters as the usual limitations of population growth. With recent advances in science and technology, including improved agricultural methods and great strides in medicine, some of the limiting factors in population growth have been lessened, with obvious results. International organisations have recommended programs to encourage general economic development in target areas along with a decrease in birth rates to effect a lasting solution.
