"Roughly 10,000 years ago, increasing population pressure on wild food resources led to a shift from food gathering (hunter-gatherers) to food production (agriculturists) in several parts of the world. This led to demand-induced technologies and demand-induced searches for higher quality energy sources, such as water power for flow irrigation, animal draft power, iron tools, and fire for land clearing and for improvement of hunting and pastoralism. Population pressures in many parts of Europe in the seventeenth and eighteenth centuries led to serious shortages of wood which in turn led to many of the technological innovations that fuelled the Industrial Revolution. Coal’s replacement of wood as the most important source of energy in Western Europe is a classic example of demand-induced innovation…promoted by population pressures on forested land in Western and Central Europe. From the end of World War II, coal’s premier importance as an energy source declined sharply and was replaced by crude oil. Far offshore drilling of oil began in 1947 off the coast of Louisiana. One year later, the world’s largest oil field, al-Ghawar in Saudi Arabia, was drilled. Large new discoveries of oil and gas in Africa and Asia combined with the development of oil super tankers and pipeline networks reduced the price of oil and gas at a time when the costs of producing coal were continuing to rise. Diesel locomotives represented a major substitution of oil for coal. The post World War II era also saw large increases in automobile ownership, the beginnings of highway and motorway road transportation networks and the first passenger jet aircraft –all benefiting from and encouraging consumption of cheap oil supplies. These increases in the consumption of crude oil have coincided with the highest population growth in history. After the depressed population growth during World War II, growth rose quickly to a peak of 2.2% in 1964, the highest rate the world has ever known. (Per capita oil consumption peaked shortly thereafter, in the 1970s). Although population continues to rise, population growth has been declining since then. If there is a relationship between energy consumption and population growth, the different types of energy consumed may have different effects. If biomass is the only energy source, populations will not grow very fast. In such organically based economies, the problem of expanding raw material supply, and especially the related problems associated with the very modest energy supply maxima…must curb growth with increasing severity as expansion takes place. The emergence of coal as an energy source eliminated the carrying capacity limits to population growth that any traditional and biomass energy based culture would eventually face. Similarly, the predominance of oil after the middle part of the twentieth century raised the carrying capacity even further."