Biology

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April 10, 2026

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April 10, 2026

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"Just 11,000 years ago, there were only roughly 5 million humans who lived on the planet Earth. The initial population growth was slow, due largely to the way humans were living—by hunting. Such lifestyle limited the size of family for practical reasons. A woman on the move cannot carry more than one infant along with her household baggage. When simple birth control means-often abstention from sex failed, a woman may elect abortion or, more commonly, infanticide to limit the family size. Further, a high mortality among the very young, the old, the ill and the disabled acted as a natural resistance to a rapid population growth. Thus it took over one million years for human population to reach the one billion mark. But the second billion was added in about 100 years, the third billion in 50 years, the fourth in 15 years, and the fifth in 12 years. Ever since humans became sedentary, some limits over the family size were lifted. With the development of agriculture, children may have become more of an asset to their families in helping with farming and other chores. By the beginning of the Christian era, human population grew to about 130 million, distributed all over the Earth. By 1650, the world population had reached 500 million. The process of industrialization had begun, bringing about profound changes over the lives of humans and their interactions with the natural world. With improved living standard, lowered death rate and prolonged life expectancy, human population grew exponentially. By 1999 there were about 6 billion people, comparing with 2.5 billion in 1950. The world population is well on its way to 7 billion with an annual growth rate of over 90 million."

- Overpopulation

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"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."

- Overpopulation

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"What determines population growth? What has been the cause of the unprecedented growth in world population in our recent history? Many socio-economic reasons are given as explanations: medical advances, improvements in public health, sanitation and hygiene, increased food availability and agricultural productivity, extension of cultivation, and development of trade and transportation. Surprisingly, high quality energy sources are rarely mentioned or quickly discounted. Yet an argument can be made that each of the above factors contributing to population growth is aided and influenced by high quality energy supplies. Cheap and abundant fossil fuels have been a necessary precondition for the past century’s population growth. And while not all countries benefit directly from the consumption of high quality energy supplies, most countries benefit from the impact of high energy societies on low energy societies. What if energy consumption, or more precisely, energy resource availability, somehow determines population growth? Perhaps energy resources determine the Earth’s carrying capacity, or how many people the Earth can support? Perhaps different energy resources have different effects on population growth? If we hypothesize that the Earth’s population is ultimately determined by availability of energy resources, and if some of those energy resources are at or near their peak rates of production, then that may affect rates of population growth. If the correlation is strong enough, the number of people the Earth can support may also be at or near its peak. Therefore the number of people in 2050 may be very different from widespread United Nations (UN) forecasts. Growing populations consume more energy. Availability of energy allows populations to grow. Energy consumption exerts demands on energy resources making them scarcer. They become harder to extract. Nearby forests are depleted, coal mines must dig deeper, oil has to be drilled in more complex environments. In other words, energy resource extraction experiences declining marginal returns. This has led to the exploitation of new energy sources, which in turn expands the Earth’s carrying capacity. Then populations grow once more."

- Overpopulation

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"Homo sapiens’ appetite is gargantuan. As we strive to get at dwindling resources for ever more people, we dig deeper into the Earth, blow the tops of mountains, divert rivers, cut down forests and pave over swaths of land. We fill the land, water, and air with our pollution. We’re driving record numbers of species to extinction and decimating others with activities from chemical poisoning to hunting for bushmeat, or simply by taking over their habitat. Greenhouse gases from our industry are changing the Earth’s climate, with such dangerous consequences as ocean acidification, rising sea levels and flooding, changes in rainfall patterns including in vital “breadbaskets,” and loss of forest cover. While the word “sustainable” has become popular, growing human numbers and activities are anything but. Increasing awareness of our impact has led to developments in renewable energy, recycling, earth-friendly farming and more. There have also been spectacular advances in family planning. But powerful—notably religious—opposition has kept governments and international bodies from actively promoting small families and prevented hundreds of millions of women who would plan their families from having access to modern methods. Those who deny that overpopulation is a problem say the poor don’t consume much. Yet the poor want nothing more than to consume more, as proved by India and China. Who can blame them? And a burgeoning number of desperately poor people does have a major impact: they cut down forests to grow food, drain rivers, deplete aquifers, and overfish and over-hunt in their local area. But make these points and you’ll be accused of blaming the poor for the problems of the rich. We seem bound to learn the hard way that there really is a limit to how many people the Earth can support. We wish it weren’t so, but it really is starting to look as if Malthus was right."

- Overpopulation

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"Many people believe that humans can have a sustainable future by using solar panels and wind turbines. Unfortunately, the only truly sustainable course, in terms of moving in cycles with nature, is interacting with the environment in a manner similar to the approach used by chimpanzees and baboons. Even this approach will eventually lead to new and different species predominating. Over a long period, such as 10 million years, we can expect the vast majority of species currently alive will become extinct, regardless of how well these species fit in with nature’s plan. The key to the relative success of animals such as chimpanzees and baboons is living within a truly circular economy. Sunlight falling on trees provides the food they need. Waste products of their economy come back to the forest ecosystem as fertilizer. Pre-humans lost the circular economy when they learned to control fire over one million years ago, when they were still hunter-gatherers. With the controlled use of fire, cooked food became possible, making it easier to chew and digest food. The human body adapted to the use of cooked food by reducing the size of the jaw and digestive tract and increasing the size of the brain. This adaptation made pre-humans truly different from other animals. With the use of fire, pre-humans had many powers. They spent less time chewing, so they could spend more time making tools. They could burn down entire forests, if they so chose, to provide a better environment for the desired types of wild plants to grow. They could use the heat from fire to move to colder environments than the one to which they were originally adapted, thus allowing a greater total population. Once pre-humans could outcompete other species, the big problem became diminishing returns. For example, once the largest beasts were killed off, only smaller beasts were available to eat. The amount of effort required to kill these smaller beasts was not proportionately less, however."

- Overpopulation

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"Currently, the operation of our present industrial civilization is almost wholly dependent on access to huge amounts of fossil fuels. It is important to understand that fossil fuels, especially oil, are not simply used to manufacture and propel passenger automobiles or trucks. They also facilitate the mass assembly of tractors, plows, irrigation pipes, and pumps and then turn around and power them also. They constitute the chemical base of many crucial fertilizers and pesticides. They are also the building blocks of agricultural plastics. They refrigerate perishables. In short, the modern industrial agriculture system could not function without copious amounts of fossil fuel. In the absence of fossil fuel-based industrial agriculture, world food production would plummet to a scale completely inadequate to sustain our current population size, let alone the net addition of over 80 million more people each year. The other side of the coin is that when humans co-opt the extraordinary power found in fossil fuels, we become “overpowered” – and that is how we are over-powering the Earth’s biosphere. We cannot destroy rainforests at the rate of several football fields per minute, trawl the deep oceans, attempt mass-scale aqua-culture, fragment habitat with asphalt roads, or construct miles and miles of urban sprawl without the power of fossil fuels. In summary, fossil fuels underwritten both our population size and growth and our discretionary (over)consumption."

- Overpopulation

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