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Population growth & its effect on environment


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Published in: Environment
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Population growth & its effect on environment

  1. 1. Problem of Population growth, poverty and environment, Population Explosion, Family Welfare Programme, Women & Child Welfare.
  2. 2. • Human population impacts environment science in many ways: • Rising populations put increasing demands on natural resources such as land, water, and energy supplies. • As human communities use more resources, they generate contaminants, such as air and water pollution and greenhouse gas emissions • They also increase larger quantities of waste  Focus of study on Demography, the science of human population. We shall explore environmental impacts of population growth and also considers questions such as:  •How does population growth or decline influence economic and social well-being?  •Does population growth enhance or diminish economic growth?  •Do specific aspects of population growth, such as age structure or sex imbalance, have bigger impacts on economic development and environmental quality than other aspects?
  3. 3. • Estimate Earth's carrying capacity? or the maximum population that it can support on a continuing basis. • Dependencies: • Food production • Total arable land • Amount of energy available to do work • Resources are not allocated equally around the world. In some areas such as the Sahel in West Africa (between the Sahara desert and more humid woodlands to the south), population growth is putting heavy stresses on a fragile environment, so food needs are outstripping food production
  4. 4. • Everyone who is alive one year from now will be one year older at that time than s/he is today. • Ages 15 to 49 are humans' prime childbearing years, biologically speaking (although resource constraints and social and political factors shape childbearing decisions differently from one country to another). • Human mortality is relatively high among infants, children, and adults over age 60, compared to other age groups. • Putting these observations together, population analysts can develop a reasonably accurate map of how a society's population size, births, deaths, and age structure are likely to evolve in the next several decades.
  5. 5. • Birth and death rates are the most important determinants of population growth; in some countries, net migration is also important in this regard. • To calculate population growth rates, demographers take the difference between births and deaths in a given time period, add the net number of migrants (which for the world as a whole is 0), and divide that number by the total population. • For example, there are now about 136 million births and 58 million deaths worldwide annually, adding a net of 78 million new inhabitants to a global population of 6.7 billion, a growth rate of nearly 1.2%
  6. 6. • Mechanization of agriculture enabled societies to produce more food. • As food supplies expanded, average levels of nourishment rose, and vulnerability to chronic and contagious diseases declined over succeeding generations. • Improvements in medical care and public health services— also helped people to live longer, so death rates fell. After several decades of lower mortality, people realized that they did not have to have so many children to achieve their desired family size, so birth rates began to fall as well. • Family size tended to decrease as women found opportunities to enter the labour force. • The costs of raising children also increased, as slightly wealthier families living in urban areas faced higher expenses for a larger array of physical and social necessities.
  7. 7. Phased reduction in death and birth rates is called demographic transition. Because death rates fall before birth rates, population growth initially speeds up. Population momentum is still significant despite decline in global fertility rate from 5 children born per woman in 1950 to a little over 2.5 in 2006.
  8. 8. • Developed nations have passed through the demographic transition, and most developing countries are at some point in the process today. • Expanded work forces can help nations increase their economic output, raising living standards for everyone. They also can strain available resources and which in turn may cause shortages and economic disruption. (Source: habitable planet)
  9. 9. • Fertility rate : • Physical factors : Woman’s child bearing years. • Non-physical factors: Relationship status; use of contraception • Fertility levels are lower in developed countries than in developing nations because more women in developed countries work outside of the home and tend to marry later and to use contraception and abortion to delay or prevent childbearing.
  10. 10. • Mortality rate : • Mortality is the second major variable that shapes population trend. • Death rates are highest among infants, young children and the elderly • To assess longevity in a society, demographers calculate life expectancy -the age that a newborn would, on average, live.
  11. 11. • Life Expectancy: • It is trending upward around the world, but a substantial gap remains between • developing and developed countries. In 2006, life expectancies at birth ranged from the mid-30s in some African countries to the high 70s or low 80s in the United States, Australia, Japan, and some European countries Reason for longevity: Satisfaction of many basic human needs such as adequate nutrition, clean water and sanitation, as well as access to medical services like vaccinations. However, New threats to health are continually emerging viz. Aids , TB
  12. 12. • Early decades of the Industrial Revolution: life expectancies were low in western world. • Thousands of people died from infectious diseases such as typhoid and cholera, in the crowded due to filthy conditions in factory towns or due to poor nutrition. • But. from about 1850 through 1950, a cascade of health and safety advances radically improved living conditions in industrialized nations. • Major milestones included: • improving urban sanitation and waste removal; • improving the quality of the water supply and expanding access to it; • forming public health boards to detect illnesses and quarantine the sick; • researching causes and means of transmission of infectious diseases; • developing vaccines and antibiotics; • adopting workplace safety laws and limits on child labor; and • promoting nutrition by providing milk, breads, and cereals with vitamins By the mid-20th century, most industrialized nations had passed through the demographic transition. As health technologies were transferred to developing nations, many of these countries entered the mortality transition and their population swelled. The population growth rate peaked in 1960s at 2%/yr (2.5% in developing countries).
  13. 13. Dependency ratio: (people who are too young or too old to work vs. working population Dependency ratios by region, 2005. Source: UN, World Population Prospects Region Total (Dependents per 100 working-age people) Children per 100 working-age people Old-age per 100 working-age people World 55 44 11 Africa 81 75 6 Latin America/Caribbean 57 47 10 Oceania 54 36 16 Asia 52 43 10 North America 49 31 18 Europe 47 23 23 Dependency ratios are key influences on economic growth. Nations with high dependency ratios spend large shares of their resources taking care of dependents, while those with lower ratios are able to devote more resources to investment in capital, technological progress, and education.
  14. 14. Dependency ratios are key influences on economic growth. Nations with high dependency ratios spend large shares of their resources taking care of dependents, while those with lower ratios are able to devote more resources to investment in capital, technological progress, and education.
  15. 15. • Earth's population by 2050 will reach • ~9 billion, if fertility decline to 2 children/woman in 2050. with max. growth occurring in developing countries • 7.7 billion, if the rate falls more sharply, to 1.5 children/woman, • 10.6 billion, if there is slower decline to 2.5 children/woman Is the population growth out of control ?
  16. 16. • Growth rates peaked in late 1960s. The world's total population is still rising because of population momentum in developing countries in ‘50s and early 1960s. • Fertility rates are falling as many developing countries pass through the demographic transition, due to factors like: • Lower infant mortality rates; education, and work opportunities for women; and increased access to family planning services.
  17. 17. • World population growth in the 21st century will be different from previous decades in several important ways. • First, humans are living longer and having fewer children, so there will be more older people (age 60 and above) than very young people (age zero to four). • Second, nearly all population growth will take place in urban areas. Third, fertility rates will continue to decline • Senior citizens can be active and productive members of society, but they have many unique needs in areas like medical care, housing and transportation. • Growing elderly populations will strain social services, especially in countries that do not have well- developed social safety nets. • As societies age, demand for younger workers will increase, drawing more women to work outside of the home, thereby decreasing fertility rate. • some countries have already dropped below replacement level (2.1): # of children per woman that keeps population levels constant when births and deaths are considered together over time. • Fertility rates in most European and some Asian and Caribbean countries currently range from about 1.2 to 1.8, well below replacement level. shrinking populations might drain national savings and reduce tax revenues.
  18. 18. • One widely-cited formula proposed by Paul Ehrlich and John Holdren in 1974 • "I = PAT" i.e. • Environmental Impact=Population x Affluence (or consumption) x Technology • Technology is sub-divided into two factors: • Resource-intensity (how much used to produce each unit of consumption) • Waste-intensity (how much waste generated for each unit of consumption) • Environmental impacts take two major forms: • First, we consume resources such as land, food, water, soils, and services from healthy ecosystems, such as water filtration through wetlands. Over-consumption uses up or severely depletes supplies of non-renewable resources, such as fossil fuels, and depletes renewable resources such as fisheries and forests if we use them up faster than they can replenish themselves • Second, we emit wastes as a product of our consumption activities, including air and water pollutants, toxic materials, greenhouse gases, and excess nutrients. Some wastes, such as untreated sewage and many pollutants, threaten human health. Others disrupt natural ecosystem functions: for example, excess nitrogen in water supplies causes algal blooms that deplete oxygen and kill fish.
  19. 19. • Rising population spurred worries that developing countries could deplete their food supplies. Starting with India in 1951, dozens of countries launched family planning programs with support from international organizations and western governments. • National programs were particularly effective in Asia, which accounted for roughly 80% of global fertility decline from the 1950s through 2000. • However, that this conclusion is controversial. Some researchers have argued that desired fertility falls as incomes grow—and that family planning has essentially no independent influence • These programs convince citizens that having large numbers of children was bad for the nation and for individual families. Generally they focused on educating married couples about birth control and distributing contraceptives, but some programs took more coercive approaches. • China imposed a limit of one child per family in 1979. • In some parts of China the one-child policy reportedly has been enforced through methods including forced abortions and sterilizations. Forced sterilizations also occurred in India in the 1970s. • These policies have spurred some Indian and Chinese families to practice selective abortion and infanticide of female babies, since boys are more valued culturally and as workers.
  20. 20. • Population sex ratios in both countries are skewed as a result. In 2005 there were 107.5 males per 100 females in India and 106.8 males per 100 females in China, compared to a worldwide average of 101.6 males per 100 females. • Females slightly outnumber males on every continent other than Asia • Large societies consume more resources than small ones, but consumption patterns and technology choices may account for more environmental harms than sheer numbers of people. The U.S. population is about one- fourth as large as that of China or India, but the United States currently uses far more energy because Americans are more affluent and use their wealth to buy energy-intensive goods like cars and electronics. • But China and India are growing and becoming more affluent, so their environmental impacts will increase. For example, in 2006 China surpassed the United States as the world's largest emitter of carbon dioxide (CO2), the main greenhouse gas produced as a result of human activities
  21. 21. • Nutritional deficiencies cause common illnesses like being underweight, while dirty water and poor sanitation spread infectious agents such as cholera and typhoid. • New threats to health are continually emerging, and often are spread across international borders through trade and human or animal migration. Recent examples that are severe enough to affect life expectancy in large areas include the HIV/AIDS pandemic and potentially avian flu and multi-drug-resistant malaria and tuberculosis. • Researchers are also gaining new insight into existing threats, such as indoor air pollution from combustion of primitive biomass fuels like crop waste and dung. • Common diseases: Pneumonia, Gastrointestinal conditions, Diarrhea, Measles, Malaria, Malnutrition etc. • Environmental investments, such as providing cleaner energy sources and upgrading sewage treatment systems, can significantly improve public health.
  22. 22. Case Study: Chula ( cooking stove) issue: • WHO estimates that 16 lakh early deaths occur annually from cooking stove pollution. • ~4- 5Lakh women and children less than 5 years die each year in India due to indoor smoke. • Chula smoke is 3rd highest cause of death after dirty Water and lack of sanitation. • What should be done to address the issue?
  23. 23. India and Natural Disasters India is one of the most disaster prone countries in the world. Over 65% land area vulnerable to earthquakes; 70% of land under cultivation prone to drought; 5% of land (40 million hectares) to floods; 8% of land (8,000 km coastline) to cyclones. A Major Disaster occurs every 2-3 years; 50 million people affected annually 1 million houses damaged annually along with human,social and other losses During 1985-2003, the annual average damage due to natural disasters has been estimated at 70 million USD Source: Ministry of Agriculture, GOI: BMTPC, Ministry of Urban Development, GOI
  25. 25. The Myths It Can’t Happen to Us. The Nature’s forces are so Deadly the Victims will Die anyway. There is Nothing We Can Do.
  26. 26.  A phenomenon or event which constitutes a trauma for a population/environment.  A vulnerable point/area that will bear the brunt of the traumatizing event.  The failure of local & surrounding resources to cope with the problems created by the phenomenon.  Types of Disasters  Natural - Manmade Ingredients of a Disaster
  28. 28.  Response  Recovery  Prevention & Mitigation  Preparedness Disaster Management Cycle
  29. 29. RESPONSE  Response measures are usually those which are taken immediately prior to and following disaster impact.  Typical measures include :  Implementation of plans  Activation of the counter-disaster system  Search and Rescue  Provision of emergency food, shelter, medical assistance etc.  Survey and assessment  Evacuation measures
  30. 30. RECOVERY  Recovery is the process by which communities and the nation are assisted in returning to their proper level of functioning following a disaster.  Three main categories of activity are normally regarded as coming within the recovery segment:  Restoration  Reconstruction  Rehabilitation
  31. 31. PREVENTION & MITIGATION  Prevention : Action within this segment is designed to impede the occurrence of a disaster event and/or prevent such an occurrence having harmful effects on communities or key installations.  Mitigation : Action within this segment usually takes the form of specific programs intended to reduce the effects of disaster on a nation or community. For instance, some countries regard the development and application of building codes (which can reduce damage and loss in the event of earthquakes and cyclones) as being in the category of mitigation.
  32. 32. PREPAREDNESS It comprises of measures which enable governments, organizations, communities and individuals to respond rapidly and effectively to disaster situations.
  33. 33. PREPAREDNESS (Contd)  Examples of Preparedness measures are :  The formulation & maintenance of valid, up-to-date counter-disaster plans  Special provisions for emergency action  The provisions of warning systems  Emergency communications  Public education and awareness  Training programs, including exercises and tests.