Presentation on theme: "The Human Population Problem Presented by Callie Price."— Presentation transcript:
The Human Population Problem Presented by Callie Price
Population Growth Immigration Deaths Emigration Births Population Growth In a closed population: Population Growth = Births – Deaths Also known as the “intrinsic rate of increase”.
Thomas Malthus was one of the first people to describe the population problem in the Essay on the Principle of Population (1798). Malthus's observation that in nature plants and animals produce far more offspring than can survive, and that man too is capable of overproducing if left unchecked. He based his theory on the population explosion that was already becoming evident in the 18th century, and argued that the number of people would increase faster than the food supply. Population would eventually reach a resource limit, and any further increase would result in a population crash, caused by famine, disease, or war. Thomas Malthus
What is carrying capacity? Carrying capacity refers to the number of individuals who can be supported in a given area within natural resource limits, and without degrading the natural social, cultural and economic environment for present and future generations. The carrying capacity for any given area is not fixed. It can be altered by improved technology, but mostly it is changed for the worse by pressures which accompany a population increase. As the environment is degraded, carrying capacity actually shrinks, leaving the environment no longer able to support even the number of people who could formerly have lived in the area on a sustainable basis. No population can live beyond the environment's carrying capacity for very long. Carrying Capacity
What is the world’s carrying capacity? There is no exact number as to how many people the world can sustain. Arguments range from the billions up to trillions of people. Highly variable when you not only consider the amount of natural resources, but the management of those resources. Carrying Capacity (Cont.)
Population Limiting Factors Density-Dependent Factors (Intraspecific Competition) Food Water Space Shelter Disease Density-Independent Factors Natural Disasters o Ex: Earthquakes, tsunamis, severe drought, etc. These limiting resources define the “carrying capacity” for a given environment.
As of April 2012, the world’s population is estimated to be around 7 billion. The United Nations projects that the human population will increase to between 8 billion and 10.5 billion in World Population
Developed countries tend to have a slower population growth rates than developing countries. Developed vs. Undeveloped Countries
Developed Countries (lower birth & death rates) Industrialized More educated Women joining the workforce Births range about 1 to 2 children per female Developing Countries (higher birth & lower death rates) Lack educational & financial means to control population growth. Births range from 4 to 7< children per female. Developed vs. Developing Countries
Food: A limiting Resource “World Hunger”
What is “hunger”? For weeks, even months, its victims must live on significantly less than the recommended 2,100 kilocalories that the average person needs to lead a healthy life. The body compensates for the lack of energy by slowing down its physical and mental activities. A hungry mind cannot concentrate. A hungry body does not take initiative. Hunger also weakens the immune system. Deprived of the right nutrition, hungry children are especially vulnerable and become too weak to fight off disease and may die from common infections like measles and diarrhoea. Each year, almost 11 million children die before reaching the age of five; malnutrition is associated with 53 percent of these deaths. From , the number of hungry people dropped from 959 million to 791 million -- mainly the result of dramatic progress in reducing the number of undernourished in China and India. In the second half of the 1990s, however, the number of chronically hungry in developing countries started to increase at a rate of almost four million per year. By , the total number of undernourished people worldwide had risen to 854 million and the latest figure is 925 million. Today, almost one person in six does not get enough food to be healthy and lead an active life, making hunger and malnutrition the number one risk to health worldwide -- greater than AIDS, malaria and tuberculosis combined
Hunger Statistics 925 million people do not have enough to eat and 98 percent of them live in developing countries. Asia and the Pacific region is home to over half the world’s population and nearly two thirds of the world’s hungry people. Women make up a little over half of the world's population, but they account for over 60 percent of the world’s hungry. 65 percent of the world's hungry live in only seven countries: India, China, the Democratic Republic of Congo, Bangladesh, Indonesia, Pakistan and Ethiopia. Under nutrition contributes to five million deaths of children under five each year in developing countries. One out of four children - roughly 146 million - in developing countries is underweight. 10.9 million children under five die in developing countries each year. Malnutrition and hunger-related diseases cause 60 percent of the deaths. Iron deficiency is the most prevalent form of malnutrition worldwide, affecting an estimated 2 billion people. Iodine deficiency is the greatest single cause of mental retardation and brain damage, affecting 1.9 billion people worldwide. It can easily be prevented by adding iodine to salt.
Impacts of Population Growth on the Environment
Depletion of Water Resources The total amount of freshwater on Earth is about 2.5 % of the total volume. Of these freshwater resources, about 70 % is in the form of ice and permanent snow cover in mountainous regions, the Antarctic and Arctic regions. Around 30% of the world's freshwater is stored underground in the form of groundwater. Freshwater lakes and rivers contain around 0.3% of the world's freshwater. Of all the freshwater available on Earth, only around 1% is accessible for human consumption. Population Growth Increased Water Requirements Depletion of Water Resources
Water Usage Of the 1% of freshwater accessible, 70% is used for agriculture, 22% for industrial, and 8% for domestic use. In many areas of the world, freshwater is being used at a rate faster than it can be replenished. Higher demands for food & products due to an increasing population, require more crops, which in turn require more water. 1 lb. of beef = 1,799 gal of water1 lb. of chicken = 468 gal of water1 gal of milk = 880 gal of water1 slice of bread = 11 gal of water1 lb. of rice = 449 gallons of water 500 sheets of paper = 1,321 gal of water
Water Quality Growing Population Demands for Increased Food Production Increase Agricultural Practices Decrease Water Quality Accumulation of Phosphorous/Nitrogen and Eutrophication Phosphorous and Nitrogen are transported through fertilizers, animal feeds, crops etc. and deposited into the soil. Increased deposits into the soil elevates the potential runoff of these into aquatic ecosystems. Runoff leads to increased amounts of nutrients available, stimulating primary production, known as “eutrophication”. Eutrophication drastically alters the biodiversity of the aquatic ecosystem causing blooms of phytoplankton and fish kills.
Deforestation Growing Population Increased Food Demands Clearing Forests for Crops or Livestock Growing Population More Space Needed Clearing Forests for Urbanization Growing Population Increased Need for Shelter Logging of Forests for Wood and Paper Products. Deforestation has many negative effects on the environment. The most dramatic impact is a loss of habitat for millions of species. 70% of Earth’s land animals and plants live in forests, and many cannot survive the deforestation that destroys their homes. Deforestation also drives climate change. Forest soils are moist, but without protection from sun-blocking tree cover they quickly dry out. Trees also help perpetuate the water cycle by returning water vapor back into the atmosphere. Without trees to fill these roles, many former forest lands can become barren deserts. Removing trees deprives the forest of portions of its canopy, which blocks the sun’s rays during the day and holds in heat at night. This disruption leads to more extreme temperatures swings that can be harmful to plants and animals.
Overfishing Growing Populations Increased Demand for Food/Money Overfishing In the mid-20th century, international efforts to increase the availability and affordability of protein-rich foods led to government efforts to increase fishing capacity. Favorable policies, loans, and subsidies spawned a rapid rise of big industrial fishing operations. These large, profit-seeking commercial fleets were extremely aggressive, scouring the world's oceans and developing ever more sophisticated methods and technologies for finding, extracting, and processing their target species. By 1989, when about 90 million tons of catch were taken from the ocean, the industry had hit its high mark, and yields have declined or stagnated ever since. Fisheries for the most sought- after species, like orange roughy, Chilean sea bass, and bluefin tuna have collapsed. In 2003, it was estimated that industrial fishing had reduced the number of large ocean fish to just 10 % of their pre-industrial population. Faced with the collapse of large-fish populations, commercial fleets are going deeper in the ocean and father down the food chain for viable catches. This so-called "fishing down" is triggering a chain reaction that is upsetting the ancient and delicate balance of the sea's biological system. A study published in Science grimly predicted that if fishing rates continue, all of the world's fisheries will have collapsed by the year 2048.
Solutions for the Human Population Problem
Solutions Family planning is essential to slowing population growth. Consciously lowering the global birthrate must become an accepted practice. Education and empowering women worldwide can reduce the birth rate as well. Careful land use planning must supercede greed, development, and carelessness. Farmable topsoil must be kept undeveloped and unpaved, watersheds must be preserved, and housing must become more efficient. Teaching communities to carefully produce their own food will reduce large-scale farming, reduce costs of food, and reduce the amounts of chemicals that enter the ecosystem. Old growth forests and original tropical rainforests must be left alone to preserve the remaining valuable species of plant and animal life necessary for medical cures and for maintaining a fully balanced ecosystem.
Technological Solutions Improvements in technology can continue to reduce the water and land requirements to raise livestock. One pound of beef requires 14% less water and 34% less land to produce than it did in Similarly, one gallon of milk requires 65% less water and 90% less land than it did in The use of technology to produce drought resistant crops and more efficient crops. Ex. “Golden Rice” – contains beta-carotene which our bodies convert to Vitamin A.
Taking Initiative The first and foremost solution to the population and environmental problems, is educating people to conserve and replenish resources. If we, as individuals, do not take the initiative to take control of the problem, it will result in more government regulations and loss of freedoms.
Conclusion Human population growth is the number one threat to the world's environment. Each person requires energy, space and resources to survive, which results in environmental losses. If the human population were maintained at sustainable levels, it would be possible to balance these environmental losses with renewable resources and regeneration. But our population is rapidly rising beyond the earth's ability to regenerate and sustain us with a reasonable quality of life. We are exceeding the carrying capacity of our planet. We need to limit our growth voluntarily, and promote contraceptive use, before Nature controls our population for us with famines, drought and plagues.