A Malthusian catastrophe (sometimes called a Malthusian check, Malthusian crisis, Malthusian dilemma, Malthusian disaster, Malthusian trap, Malthusian controls or Malthusian limit) is a return to subsistence-level conditions as a result of population growth outpacing agricultural production. Subsistence is the food necessary to sustain life The following is a list of subsistence techniques: Hunting and Gathering Demography is the statistical study of all Populations. It can be a very general science that can be applied to any kind of dynamic population that is one that changes over Agriculture refers to the production of goods through the growing of plants and fungi and the raising of domesticated Animals The study of agriculture Later formulations consider economic growth limits as well. Economics is the social science that studies the production distribution, and consumption of goods and services. Based on the work of mathematician Thomas Malthus (1766-1834), theories of Malthusian catastrophe are very similar to the subsistence theory of wages. Thomas Robert Malthus FRS (13 February 1766 – 23 December 1834 was an English political economist and demographer who expressed views The Subsistence Theory of Wages, also known as the "Iron Law of Wages" was a law of economics that asserted that real wages in the long run would trend toward the value needed The main difference is that the Malthusian theories predict over several generations or centuries whereas the subsistence theory of wages predicts over years and decades.
An August 2007 science review in The New York Times raised the claim that the Industrial Revolution had enabled the modern world to break out of the Malthusian Trap, while a front page Wall Street Journal article in March 2008 pointed out various limited resources which may soon limit human population growth because of a widespread belief in the importance of prosperity for every individual and the rising consumption trends of large developing nations such as China and India. The Industrial Revolution was a period in the late 18th and early 19th centuries when major changes in agriculture manufacturing and transportation had a profound effect on the China ( Wade-Giles ( Mandarin) Chung¹kuo² is a cultural region, an ancient Civilization, and depending on perspective a National India, officially the Republic of India (भारत गणराज्य inc-Latn Bhārat Gaṇarājya; see also other Indian languages) is a country 
I think I may fairly make two postulata. Thomas Robert Malthus FRS (13 February 1766 – 23 December 1834 was an English political economist and demographer who expressed views The book An Essay on the Principle of Population was first published anonymously in 1798 through J First, That food is necessary to the existence of man. Secondly, That the passion between the sexes is necessary and will remain nearly in its present state. These two laws, ever since we have had any knowledge of mankind, appear to have been fixed laws of our nature, and, as we have not hitherto seen any alteration in them, we have no right to conclude that they will ever cease to be what they now are, without an immediate act of power in that Being who first arranged the system of the universe, and for the advantage of his creatures, still executes, according to fixed laws, all its various operations.
. . .
Assuming then my postulata as granted, I say, that the power of population is indefinitely greater than the power in the earth to produce subsistence for man. Population, when unchecked, increases in a geometrical ratio.
– Malthus 1798, Chapter 1, online
A series that is increasing in geometric progression is defined by the fact that the ratio of any two successive members of the sequence is a constant. In Mathematics, a geometric progression, also known as a geometric sequence, is a Sequence of Numbers where each term after the first is found For example, a population with an average annual growth rate of, say, 2% will grow by a ratio of 1. 02 per year. In other words, the ratio of each year's population to the previous year's population will be 1. 02. In modern terminology, a population that is increasing in geometric progression is said to be experiencing exponential growth. Exponential growth (including Exponential decay) occurs when the growth rate of a mathematical function is proportional to the function's current value
Alternately, in an arithmetic progression, any two successive members of the sequence have a constant difference. In Mathematics, an arithmetic progression or arithmetic sequence is a Sequence of Numbers such that the difference of any two successive members In modern terminology, this is called linear growth.
If unchecked over a sufficient period of time, and if the ratio between successive sequence members is larger than 1. 0, then exponential growth will always outrun linear growth. Malthus saw the difference between population growth and resource growth as being analogous to this difference between exponential and linear growth. Even when a population inhabits a new habitat – such as the American continent at Malthus' time, or when recovering from wars and epidemic plagues – the growth of population will eventually reach the limit of the resource base. (Malthus 1798, chapter 7: A Probable Cause of Epidemics).
Neo-Malthusian theory argues that unless at or below subsistence level, a population's fertility will tend to move upwards. Neo-malthusianism is a set of doctrines derived from Thomas Malthus 's theory that limited resources keep populations in check and reduce economic growth Fertility is the natural capability of giving life As a measure "Fertility Rate" is the number of children born per couple person or population Assume for example that a country has 10 breeding groups. Over time this country's fertility will approach that of its fastest growing group in the same way that
will eventually come to resemble
regardless of how large the constant a is or how small the constant b is. Under subsistence conditions the fastest growing group is likely to be that group progressing most rapidly in agricultural technology. Technology is a broad concept that deals with a Species ' usage and knowledge of Tools and Crafts and how it affects a species' ability to control and adapt However, in above-subsistence conditions the fastest growing group is likely to be the one with the highest fertility. Therefore the fertility of the country will approach that of its most fertile group. This, however, is only part of the problem.
In any group some individuals will be more pro-fertility in their beliefs and practices than others. According to neo-Malthusian theory, these pro-fertility individuals will not only have more children, but also pass their pro-fertility on to their children, meaning a constant selection for pro-fertility similar to the constant natural selection for fertility genes (except much faster because of greater diversity). Natural selection is the process by which favorable Heritable traits become more common in successive Generations of a Population of History See also History of genetics The existence of genes was first suggested by Gregor Mendel (1822-1884 who in the 1860s studied inheritance According to neo-Malthusians, this increase in fertility will lead to hyperexponential population growth that will eventually outstrip growth in economic production. This appears to make any sort of voluntary fertility control futile, in the long run. Neo-Malthusians argue that although adult immigrants (who, at the very least, arrive with human capital) contribute to economic production, there is little or no increase in economic production from increased natural growth and fertility. Human capital refers to the stock of skills and knowledge embodied in the ability to perform labor so as to produce Economic value. Neo-Malthusians argue that hyperexponential population growth has begun or will begin soon in developed countries.
To this can be added that, unknown to Malthus, farmland deteriorates with use. Some areas where there was intensive agriculture in classic times (i. e. , the feudal era) had already declined in population because their farmland was worn out, long before he wrote.
At the time Malthus wrote, and for 150 years thereafter, most societies had populations at or beyond their agricultural limits. After World War I, the growth rate of the world's population accelerated rapidly, resulting in predictions by Paul R. Ehrlich and many others of an imminent Malthusian catastrophe. World War I (abbreviated WWI; also known as the First World War, the Great War, and the War to End All Paul Ralph Ehrlich (born May 29 1932 in Philadelphia Pennsylvania) is a renowned Entomologist specializing in Lepidoptera (butterflies However, the so-called Green Revolution produced a contemporaneous exponential increase in the world's food supply, and the date of the predicted Malthusian collapse had been temporarily forestalled, until the peaking of agricultural production began to occur in the 1990s in several world regions. The Green Revolution refers to the transformation of Agriculture that began in 1945 at the request of the Mexican government to establish an agricultural research station to
David Pimentel and Ron Nielsen, working independently, found that the human population has passed the numerical point where all can live in comfort, and that we have entered a stage where many of the world's citizens and future generations are trapped in misery.  There is evidence that a catastrophe is underway as of at least the 1990s; for example, by the year 2000, children in developing countries were dying at the rate of approximately 11,000,000 per annum from strictly preventable diseases.  This data suggests that by the standard of misery, the catastrophe is underway. The term 'misery' can generally be construed as: high infant mortality, low standards of sanitation, malnutrition, inadequate drinking water, widespread diseases, war, and political unrest. Infant mortality is defined as the number of deaths of Infants (one year of age or younger per 1000 live births Malnutrition is a general term for a medical condition caused by an improper or insufficient diet. Water Crisis is a term that refers to the status of the world’s Water resources relative to human demand
Regarding famines, data demonstrates the world's food production has peaked in some of the very regions where food is needed the most. For example in South Asia, approximately half of the land has been degraded such that it no longer has the capacity for food production.  In China there has been a 27% irreversible loss of land for agriculture, and continues to lose arable land at the rate of 2,500 square kilometres per year.  In Madagascar, at least 30% of the land previously regarded as arable is irreversibly barren. Madagascar, or Republic of Madagascar (older name Malagasy Republic) is an Island nation in the Indian Ocean off the southeastern On the other hand, recent data shows the number of overweight people in the world now outnumbers that of malnourished, and the rising tide of obesity continues to expand in both rich and poor countries. Obesity is a condition in which excess Body fat has accumulated to such an extent that health may be negatively affected 
Many technologically developed countries have by 2006 passed through the demographic transition, a complex social development in which total fertility rates drop in response to lower infant mortality, more education of women, increased urbanization, and a wider availability of effective birth control causing the demographic-economic paradox. The Demographic transition model (DTM is a model used to explain the process of shift from high Birth rates and high Death rates to low birth rates and low death rates The total fertility rate ( TFR, sometimes also called the fertility rate, period total fertility rate (PTFR or total Infant mortality is defined as the number of deaths of Infants (one year of age or younger per 1000 live births Urbanizationn (also spelled urbanisation) is the physical growth of Urban areas into rural or natural land as a result of population in-migration to an existing Birth control, sometimes synonymous with contraception, is a regimen of one or more actions devices or Medications followed in order to deliberately prevent The demographic-economic paradox is the inverse Correlation found between wealth and fertility within and between nations By the end of the 21st century, these countries could avoid population declines by permitting large-scale immigration. Immigration refers to the movement of people among countries While the movement of people has existed throughout human history at various levels modern immigration implies long-term On the assumption that the demographic transition is now spreading to less developed countries, the United Nations Population Fund estimates that human population may peak in the late 21st century rather than continue to grow until it exhausted available resources. Developing countries are countries that haven't reached Western-style standards of democratic government free market economy industrialization social programs and human rights guaranties The United Nations Population Fund ( UNFPA) began operations in 1969 as the United Nations Fund for Population Activities (the name was changed in 1987  Some have expressed doubt about the validity of the UN projections, claiming that they are below the projections by others.  The most important point is that none of the projections show the population growth beginning to decline before 2050. Indeed, the UN "high" estimate does not decline at all, even out to 2300, indicating the potential for a Malthusian catastrophe. 
The actual growth curve of the human population is another issue. In the latter part of the 20th century many argued that it followed exponential growth; however, a more recent view is that the growth in the last millennium has been faster, at a superexponential (possibly hyperbolic, double-exponential, or hyper-exponential) rate. Exponential growth (including Exponential decay) occurs when the growth rate of a mathematical function is proportional to the function's current value When a quantity grows towards a Singularity under a finite variation it is said to undergo hyperbolic growth. A double exponential function is a Constant raised to the power of an Exponential function. In Mathematics, tetration (also known as hyper -4  Alternatively, the apparently exponential portion of the human population growth curve may actually fit the lower limb of a logistic curve, or a section of a Lotka–Volterra cycle. A logistic function or logistic curve is the most common Sigmoid curve. The Lotka–Volterra equations, also known as the predator-prey equations, are a pair of first order Non-linear, Differential equations frequently used
Historians have estimated the total human population on earth back to 10,000 BC.  The figure on the right shows the trend of total population from the year 500 AD to 2005, and from there in three projections out to 2150 (low, medium, and high).  If population growth were exactly exponential, then the trend would be a straight line on this semilog graph. In Science and Engineering, a semi-log graph or semi-log plot is a way of visualizing data that are changing with an exponential relationship The fact that it has been curving upwards indicates faster-than-exponential growth over the last 1500 years of history. However, the United Nations population projections out to 2150 (the red, orange, and green lines) show a possible end to this phenomenon occurring as early as 2050 in the most optimistic scenario, and by 2075 in the "medium" scenario.
The graph of annual growth rates (below) also does not appear exactly as one would expect for long-term exponential growth. For exponential growth it should be a straight line at constant height, whereas in fact the graph from 1800 to 2005 is dominated by an enormous hump that began about 1920, peaked in the mid-1960s, and has been steadily eroding away for the last 40 years. The sharp fluctuation between 1959 and 1960 was due to the combined effects of the Great Leap Forward and a natural disaster in China. The Great Leap Forward ( of the People's Republic of China (PRC was an economic and social plan used from 1958 to 1960 which aimed to use China 's vast population  Also visible on this graph are the effects of the Great Depression, the two world wars, and possibly also the 1918 influenza pandemic. The 1918 flu pandemic (commonly referred to as the Spanish flu) was an Influenza Pandemic that spread to nearly every part of the world
Though short-term trends, even on the scale of decades or centuries, cannot prove or disprove the existence of mechanisms promoting a Malthusian catastrophe over longer periods, the prosperity of a small fraction of the human population at the beginning of the 21st century, and the debatability of ecological collapse made by Paul R. Ehrlich in the 1960s and 1970s, has led some people, such as economist Julian L. Simon, to question its inevitability. Ecological Collapse refers to a situation where an Ecosystem suffers a drastic if not permanent reduction in Carrying capacity for all organisms often resulting Paul Ralph Ehrlich (born May 29 1932 in Philadelphia Pennsylvania) is a renowned Entomologist specializing in Lepidoptera (butterflies Julian Lincoln Simon (born February 12, 1932; died February 8, 1998 in Chevy Chase Maryland of Heart attack) was 
A 2004 study by a group of prominent economists and ecologists, including Kenneth Arrow and Paul Ehrlich suggests that the central concerns regarding sustainability have shifted from population growth to the consumption/savings ratio, due to shifts in population growth rates since the 1970s. Kenneth Joseph Arrow (born August 23, 1921) is an American Economist and joint winner of the Nobel Memorial Prize in Economics Empirical estimates show that public policy (taxes or the establishment of more complete property rights) can promote more efficient consumption and investment that are sustainable in an ecological sense; that is, given the current (relatively low) population growth rate, the Malthusian catastrophe can be avoided by either a shift in consumer preferences or public policy that induces a similar shift.
However, some contend that the Malthusian catastrophe is not imminent. A 2002 study by the UN Food and Agriculture Organization predicts that world food production will be in excess of the needs of the human population by the year 2030; however, that source also states that hundreds of millions will remain hungry (presumably due to economic realities and distribution issues).
Another way of applying the Malthusian theory is to substitute other resources, such as sources of energy for food, and energy consumption for population. Energy development is the ongoing effort to provide sufficient Primary energy sources and secondary Energy forms to meet civilization's needs (Since modern food production is energy and resource intensive, this is not a big jump. Most of the criteria for applying the theory are still satisfied. ) Since energy consumption is increasing much faster than population and most energy comes from non-renewable sources, the catastrophe appears more imminent, though perhaps not as certain, than when considering food and population continue to behave in a manner contradicting Malthus's assumptions.
Retired physics professor Albert Bartlett, a modern-day Malthusian, has lectured on "Arithmetic, Population and Energy" over 1,500 times. Albert A Bartlett is an emeritus Professor of Physics at the University of Colorado at Boulder, USA Thomas Robert Malthus FRS (13 February 1766 – 23 December 1834 was an English political economist and demographer who expressed views He published an article entitled Thoughts on Long-Term Energy Supplies: Scientists and the Silent Lie in Physics Today (July 2004). For a response to Bartlett's argument, see two articles on energy and population in Physics Today, November 2004, and following letters to the editor.
A further way of analyzing resource limitation is the dwindling area for storage of soil contaminants and water pollution. Soil contamination is caused by the presence of man-made chemicals or other alteration in the natural soil environment Water pollution is the contamination of Water bodies such as Lakes Rivers Oceans and Groundwater caused by human activities The high rate of increase in toxic chemicals in the environment (especially persistent organic chemicals and endocrine altering chemicals) is creating a circumstance of resource limitation (e. g. safe potable water and safe arable land).