Overpopulation and development
Overpopulation u The number of people in a region is greater than the ability of the land to support them u Carrying capacity= no. of people a region can support with its basic resources
u Optimum Population – no of people in a region with high standard of living given regions level of development and natural resources at any time u Under population – no of people living in area cannot exploit fully the natural resources u Inward migration improves SOL for all u Ireland 1997 -2007 – labour shortages u 2007 onwards and 1840’s overpopulated, Sahel; Africa and Bangladesh also
Influence of Society and culture on Population u Status of women: – Low status, low education (62% of women in India are illiterate), Marry young, male heir imp, high rate of malnutrition u India 20% of maternal deaths and 25% of child deaths world wide u Religion: – Strong religion = high BR – Oppose abortion and contraception (Catholic and Islamic) – Catholic influence is declining
u Local customs: – India, number of children = virility – Sons seen as economic advantage – Large families are insurance policy u Provision of Healthcare: – Better HC and clean water – lower child mortality – Somalia infant mortality is 118. 5/1000 – Norway 3. 7/1000
Causes of overpopulation 1. 2. 3. High birth rates: demand on basic resources increase ie. The Sahel Migration: people forced to leave areas puts new areas under pressure ie. Darfur in Sudan Overuse of sources: resources that the population depend on becoming overused leading to overpopulation ie. Cod banks in the north atlantic
Factors to increase carrying capacity Factors How these factors work 1. Decreasing population Reduces demand for basic resources 2. Fertilisers Increase food supply and feed more people 3. New farming methods Feed more people 4. Irrigation Raises crop yields, more water 5. Better crops/ animals Feed more people 6. Land reclamation Provides new land for settlement and farming
Factors to decrease carrying capacity Factors How these factors work 1. Population growth Raises demand for basic resources 2. Soil erosion Reduces food supply 3. Deforestation Reduces fuel supply/ increases soil erosion 4. Flooding Destroys living space and farmland 5. Overgrazing/ over cropping Damages soil and reduces food supply 6. Urbanisation Raises demand for resources/ reduces farmland 7. Climate change Makes land areas uninhabitable
Case study: The Sahel u u An area stretching across northern Africa 5, 0000 km long and 300 km wide Savannah land south of Sahara, semiarid zone Limited resources, rainfall in downpours and evaporates quickly
Impact of the development of resources u Extends from Senegal (west) through Mauritania, Mali, Burkino Faso, Niger, Northern Nigeria, Sudan to Ethopia. u Poor quality soil only supports nomadic herders u Overgrazing causes desertification u Sahara extending 10 km a year
Causes of Overpopulation u Climate Change – rainfall unpredictable, getting less rain due to global warming, 02 -06 no crops grew due to water shortage u Heavy downpours wash away the hard baked soil- these are most fertile soils u Soils are mainly Laterite and sand, don’t hold water well u High Temp and evaporation, led to wells drying up and droughts and famines e. g. 1983 -1985
u Unsustainable farming methods: u Cattle number exceed carrying capacity – cattle seen as wealth, 1950 -70 cattle numbers doubled, overgrazing u New wells discourage nomadic life, land stripped bare, roots no longer bind soil together, erosion u Deforestation due to fire and building material – Particularly bad at edge of desert where shrubs and trees would prevents deserts spread
u Population u u u Growth: Early expanding stage BR is 39, DR is 10 Increase in Refugees due to civil war and famine 1 m fled from Ethiopia to Sudan Pressure to grow cash crops e. g. cotton, led to nutrients being leached due to over cropping, failure to rotate, and using dung as fuel not fertiliser As soils become exhausted more land is need to produce same amount of crops
Effects of Over Population u Socio-economic: – Human Activities main cause, frequency of famine due to overuse of resources – Increasing pop and refugees strain resources – Cash crops use land that used to provide food for locals – Nomadic way of life over so cattle strip land bare – Refugees dependent on aid and assistance
u Environmental: – Change in rainfall – lake chad now 1/20 th of size since 1970 – Fishing boats seen stranded many miles from current shoreline – Conflict between Nigeria and Cameroon re fishing areas, borders no clearly defined as lake once occupied this area
Case study Focus on Sudan u Same size as France u Barren land u 33% of population live in 7% of land u Capitol city Khartoum u Stage 2 u
Factors contributing to overpopulation and overuse of soils 1. Birth rate: birth rate = 33 per thousand u death rate = 10. 28 per thousand u Population 43 million u Infant mortality rates= 81 per thousand u ½ population under 18= HDR Led to a number of problems: v Overgrazing: status of cattle v Deforestation: need of fuel, manure often used (no natural fertilizer in the soil) v over cultivation: use of cash crops to pay debt u
Factors contributing to overpopulation and overuse of soils 2. Migration and conflict: u Civil war and famine led to internal migration u Since 2003 Darfur has become a human rights crisis region u 120, 000+ fled to Chad or to area at the east of Sudan u Suffering brain drain u Influx of 1 milliion+ from Ethiopia
Factors contributing to overpopulation and overuse of soils 3. Environmental degradation: u u u Global warming: increased temp and evaporation Droughts reduces food production Rainfall levels decreased by 30% over 20 yrs leading to drying of soil triggering erosion Wells drying up and droughts 1968 -73, 1983 -5, dug lower which lowers the water table Desertification caused by deforestation and drought cause the Sahara desert to spread southward by 10 km a year
Unsustainable Farming Methods CAUSE EFFECT OVERGRAZING u. Cattle OVERCULTIVATION. FARMERS ARE FORCED TO GROW CROPS ON POOR LAND u. THE DEFORESTATION. TREES ARE REMOVED FOR FUEL AND TO CLEAR LAND FOR CROPS u. REDUCED exceed carrying capacity u. Indication of wealth and importance u. GRASS CANNOT REGROW u. SOIL EROSION u. DESERTIFICTION CONTINUAL USE OF THE SOIL LEADS TO LOSS OF SOIL STRUCTURE. THE SOIL IS EASILY BLOWN AWAY BY DESERT WINDS u. SOIL EROSION u. DESERTIFICATION TRANSPIRATION OF MOISTURE FROM PLANTS LEADS TO LESS RAINFALL u. ANIMAL MANURE USED AS FUEL INSTEAD OF WOOD. NO LONGER USED TO FERTILIZE THE GROUND u. REDUCED CROP COVER
Effects of overpopulation u Socio-economic – Soil degradation – Cash crops on valuable land – Increasing population – Farmers more sedentary – Refugees not self reliant u Environmental – Change in rainfall patterns – Conflict over water
OVERPOPULATION AND INCOME u u u v v v Areas with highest birth rates and highest levels of population growth have the highest levels of poverty poorer countries have a higher birth rate Children are seen as economic assets In high income families – children an economic liability - $100, 000 to rear child 1 -18 yrs Education of women central to decline in birth rate UN Development Programme: 1. 3 billion live on less than. 77 cent a day 800 million people do not get enough to eat 500 million are chronically malnourished
Impact of Income levels on development u u u Highest BR and Pop growth = Highest levels of poverty Poor people = larger families, economic asset High population density not sole indicator of poverty & population High income families – children an economic liability Education of women central to decline in birth rate
Income levels and development u u u u Kenya Pop 39. 8 m Density of 69 km poor, mainly rural Stage 2 Population growing rapidly (fertility rates high) 42% of pop= 1 -14 age group Low incomes Women low social status Low quality education and health services Infrastructure poor Foreign investment weak Underemployment and unemployment high Low pop density but is overpopulated u u u South Korea Pop 49 m Density of 487 km Successful economy, exports orientated Stage 4 Population growing slowly Economy developed per capita income improved High quality education and health Densely populated Modern lifestyle and a good standard of living Unemployment remains low High pop density but it is not overpopulated
Impact of technology on population: medical technology u u u u u World pop doubled in 40 yrs Medical research has developed vaccinations as preventative measures Improved access to family planning Vaccinations have been developed to cure/prevent infections ie. Measles etc Infant mortality rates decreased Some are cheap and administrated in primitive conditions by use of syringe Better education more women starting families later Rate of increase not as rapid as a result Geneline therapy promised to eliminate fatal human diseases
Impact of technology on population: agricultural technology Increase in food supply leads to longer life expectancy Advance Results 1. Improved fertilisers pesticides, herbicides Increased yields, reduce crop loss 2. New strains of plants Able to grow and thrive in strained conditions 3. Chemicals New pesticides and herbicides allow food to thrive 4. Glasshouses Able to grow plants in artificial conditions all year round 5. Machinery Harvesters, planters, pickers gather more crops increasing yields, allow more land to be cultivated 6. Selective animal breeding Increased meat and milk yields from each animal 7. Irrigation Brings formerly dry land into production and fungicides,
HIV u u Causing Rising death rates in India and Africa Expensive antiretrovial drugs can help but not reaching those that need them MNC’s wont allow cheaper version of the drug to be made South Africa 5. 7 m people are HIV positive – Policy change now allows HIV positive mothers to be treated so they wont pass it on to children
u People in south are not malnourished because of a lack of food but because they are priced out of their reach u EU food mountains formed with excess food u Excess food sometimes sold to south but at very high prices
Ecological footprint and sustainability u u u u Ecological footprint - Area of forest land, agricultural land, recreational space etc required by a person to live Several hectares person in the developed world V less than 1 hectare in developing world 2006 Switzerland 5. 6 hectares But China 1. 8 hectares Sustainability is based on the recognition that when a resource is consumed faster that it is produced or renewed the source runs out Technology can make a positive difference Developed world needs to change – buy food locally, reduce air travel etc
GM foods & The Green Revolution u u Green Revolution – increase in food production, technology and research in 1960’s GM food (Genetically Modified) have potential to reduce/eliminate food shortages Modified for desired traits e. g. Disease resistance, increase yield up to 5 times, increase salt tolerance, increase nutritional value India pop increase from 361 m to 1094 m could not be fed without GM food
u Disadvantages: – Expensive products and equipment u Unavailable to small farmers who need them most – Oil derived fertilisers- non renewable resource – Genetic diversity reduced – farmers abandoning traditional crops for higher yielding GM foods
Population growth and developed countries Developed countries are in stage 4 and 5 u Agricultural and industrial revolution caused economic growth in Europe u Tax revenue allowed for continued investment in health and education u Increase in life expectancy and lower birth rate u Today high standards of living , aging population and high GNP u
Population growth and developing countries u u u Stage 2 many countries experiencing high population growth 30% under the age of 14 yrs Increase need of food, infrastructure, education and services Civil wars, corrupts leadership and MNC’s Not experiencing economic development in the same way that Europe did as due to unfair trading systems Migration to shanty towns – cities pop can double in 15 yrs Low incomes cannot afford to invest in education and health Large families needed to provide economic security Very young age dependency ratio Population growth increase in rural-urban migration Brain drain: leave to find well paid work else where Loss slows down economic progress in country of origin
Over population impacts on society and culture in Bangladesh u u u Poor country, flood plain of Ganges & Bramaputra Primary economic activity: agriculture Population: 158 million+ 28% urban areas 1100 per km squared Causes of over population – Risk of flooding u Low lying delta u Annual monsoon season, typhoons over Bay of Bengal u 1 m of water floods 20% of Bangladesh land u Sterilises agri land contanimates water u Infection: typhoid and cholera
u Social Factors: – Stage 3 (late expanding stage) – Birth Rates declining with family planning (difficult due to Muslim faith) – 4 births per mother in 1990 but only 2. 6 in 2011 – Muslim: Marry young, arranged marriages, desire for sons – Adult literacy rate only 47%
Effects of overpopulation Bangladesh u Migration – Land scarce, live in vulnerable areas, greater risk, – Rural to urban migration, Dhaka, lack skills, live in shanty towns outside city u Overcrowding – Both rural and urban areas – Shanty towns= high mortality rates, high unemployment, poverty – Women, find jobs as domestic servants in Persian Gulf- remittance
2006 Question u Sahel u Definition of OP u Causes – Climate change – Pop growth – Farming methods – Resources running out u Effects – Socio economic
Скачать презентацию Overpopulation and development Overpopulation u The number
8e69ac4df0b9d2d729ec9be9a4a57a24.ppt