that expanding population leads to agricultural intensification and development of more productive and less labor-intensive methods of farming. Thus, human population levels determines agricultural methods, rather than agricultural methods determining population. Environmentalist founder of Ecomodernism, Stewart Brand, summarized how the Malthusian predictions of The Population Bomb and The Limits to Growth failed to materialize due to radical changes in fertility that peaked at a growth of 2 percent per year in 1963 globally and has since rapidly declined. While 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, due to the prosperity of a major fraction of the human population at the beginning of the 21st century, and the debatability of the predictions for ecological collapse made by Paul R. Ehrlich in the 1960s and 1970s, some people, such as economist Julian L. Simon who wrote The Ultimate Resource which it contends is human technology and medical statistician Hans Rosling questioned its inevitability. Joseph Tainter asserts that science has diminishing marginal returns and that scientific progress is becoming more difficult, harder to achieve, and more costly, which may reduce efficiency of the factors that prevented the Malthusian scenarios from happening in the past. The view that a "breakout" from the Malthusian trap has led to an era of sustained economic growth is explored by "unified growth theory". One branch of unified growth theory is devoted to the interaction between human evolution and economic development. In particular, Oded Galor and Omer Moav argue that the forces of natural selection during the Malthusian epoch selected beneficial traits to the growth process and this growth enhancing change in the composition of human traits brought about the escape from the Malthusian trap, the demographic transition, and the take-off to modern growth. See also Antinatalism Cliodynamics Conservative Party (UK) Demographic trap Food Race History of economic thought Jevons paradox John B. Calhoun National Security Study Memorandum 200 - a U.S. National Security Council Study advocating population reduction in selected countries to advance U.S. interests Overshoot (population) Political demography Population cycle Subsistence theory of wages Notes References Korotayev, A., Malkov A., Khaltourina D. Introduction to Social Macrodynamics: Compact Macromodels of the World System Growth. Moscow: URSS, 2006. Korotayev A., Malkov A., Khaltourina D. Introduction to Social Macrodynamics: Secular Cycles and Millennial Trends. Moscow: URSS, 2006. See especially Chapter 2 of