Malthus stated that, the populations’, of the world would increase in geometric proportions while the food resources available for them would increase only in arithmetic proportions. In simple words, if human population was allowed to increase in an uncontrolled way, then the number of people would increase at a faster rate than the food supply. A point would come when human populations of the world reach the limit up to which food sources could support it. Any further increase would lead to population crash caused by natural phenomena like famine or disease. According to him, human society could never be perfected. He believed that man is a lazy animal, who would lead a satisfied life and procreate as long as his family was well fed.
However, as soon as human population would feel constraints in food supply due to increase in population, he would again work hard to provide enough for his family. This might lead to an increase in agricultural production to provide for all , but at the same time man would be back to his complacent stage , where all his needs would be fulfilled .this would start the cycle of overpopulation and food shortage , all over again .having been a clergy ,Malthus validated his theory on moral grounds that suffering was a way of making human beings realize the virtues of hard work and moral behavior .such kind of suffering due to overpopulation and limited food supply was inevitable. Malthus theory was based on the assumption that the power of population to multiply is much greater than the power of the earth to provide subsistence for man .in his own words passion between the sexes is an inevitable phenomenon , hence , when unchecked, population would grow at such a high rate that it would outstrip food supply.
According to him, disease, food shortage and death due to starvation, were nature’s way to control population. He proposed that human being adopt measure like infanticide, abortion, delay in marriage and strict following of celibacy to check population growth. Malthus made three major errors. First, he did not foresee and probably could not have foreseen, the impacts of the industrial revolution on agricultural, the mechanization of food production simply rendered the assumption of a linear increase untenable .the world supply of food has consistently outpaced population growth, meaning that productivity growth in agriculture has been higher than the rate of increase in the number of the people.
Second, Malthus did not foresee the impacts of the opening up of mid latitude grasslands in much of the world. Third Malthus analysis of fertility was deeply flawed during the industrial revolution, total fertility rates declined and family sizes decreased, in the 1960 when the world experienced average population growth rates in excess of 2.6% annually Malthusianism underwent a revival in the form of Neo-Malthusianism .Neo-Malthusianism acknowledged the errors that Malthus made but maintained that while he may have been wrong in the short run, much of his argument was correct in the long run ,it has been only in the last thirty years that Malthusian theory has once more gained an audience in the population debate .
The oil crisis of the 1970 open the window again at his theory the oil is renewable resource and the human numbers are increasing wildly so not only the food is the problem now oil ,minerals ,land ,and water are a big issue facing the world .The land ,in addition to arguing that there is not enough land to support humanity ,some have argued that we are actually losing existing arable land through poor farming practices and through the desertification in other hand official UNFAQ data demonstrate that agricultural land as a percentage of the total land area has increased over the last thirty years from 33.13% to 35.71% most of the large gains have occurred in developing areas such as Latin America .
Food ,global food production has enjoyed tremendous gains over the last twenty years . most of these gains are due to the technological advances made through the green revolution, recently through there has been concern in some sectors that the green revolution has lost its edge and is no longer able to ensure that production levels keep pace with population growth .however, this view does not take into account that current yields are not at best practice levels.
The Water ,the real water problem ,hydrologist say ,is not the quantity but the way it is distributed ,the water like ,most other resources is product of human labor and ingenuity .people create usable water and there are large opportunities to discover and utilize new sources. It has been shown that the neo-Malthusian perspective is seriously flawed on many levels.