Ecological Footprint
The demographic transition (4 stages)
- Pre-industrial stage: Birth rate and death rate are high - Transitional stage: Birth rate increases and death rate decreases -Industrial stage: Birth rate declines due to increased opportunities for women and access to birth control - Post Industrial stage: Birth rate and death ratw are low As mortality rate decreases, there is less need for large families. Parents invest in quality of life!
Ecological Footprint
-Ecological footprint is the area of land and stream/river/ocean required to support our consumption of food, goods, services, housing, and energy and to assimilate our wastes. - or a measure of humanity's demand on nature - Everyone requires a certain portion of the biosphere for extracting the resources he/she needs and absorbing the waste generated.
Ecological Footprint
6 acres per person global average - 10 for a Swiss - 4 for a Chinese - 24 for an American
Challenges in Biodiversity
Biodiversity: the cumulative number and diversity of living things • Human actions have driven many species extinct - Biodiversity is declining dramatically - We are setting in motion a mass extinction event Biodiversity loss may be our biggest problem; once a species is extinct, it is gone forever
Population Pyramid
Graphical illustration that shows various age group in a population. Note that age structure affects population size Wide base = many young: - High reproduction, high level of technology, food abundance, no wars Rapid population growth • Even age distribution: - Remains stable
Factors Affecting Population
Immigration and emmigration: War, civil strife, and environmental degradation cause people to flee their homes - Each year, 25 million refugees escape poor environmental conditions • This movement causes environmental problems - No incentives to conserve resources
Factors Affecting Population (cont.)
Life expectancy is increasing • Life expectancy = average number of years that an individual is likely to continue to live - Increases with reduced rates of infant mortality - In countries with good sanitation, health care, and food, people live longer
Population Growth is Exponential
Linear/Arithmethic growth: when the amount added over successive time period remain the same eg. 1,2,3,4,5, ..... • Exponential growth: when the amount added over successive time period keep increasing eg. 1,2,4,8,16,32,64.....
What is considered the greatest environmental problem facing the world today?
Most scientists would argue that overpopulation is the greatest problem facing the world today. - Increasingly large numbers of people must be fed, housed, and clothed, with a minimal impact on the environment.
Ecological Footprints are not all equal
Not everyone benefits equally from rising affluence • The ecological footprints of countries vary greatly - The U.S. footprint is much greater than the world's average - Affluence increases consumption - People in rich nations have much larger ecological footprints • In the U.S. the richest 1% - Have 25% of all income
Human Population
Our population grows by over 80 million each year • It took until 1800 to reach approx. 1 billion • In 1930 (130 years later) we reached 2 billion -This growth rate is called exponential growth
Population Bomb
Our world at approximately seven billion • Populations continue to rise in most countries - Particularly in poverty-stricken nations • Although the rate of growth is slowing, we are still increasing in numbers
Impacts of Population
Pollution: Pollution of air and water resources is a serious issue that affect both natural ecosystem and our quality of life Landslides: Urbanization: Human activities are most likely to cause landslides in urban areas Impacts of population All these can impact landslide in a place! • Housing development into steep slopes, inadequate control of storm water runoff, modification of sensitive slopes -Timber harvesting in weak, relatively unstable areas -Artificial fillings of loose materials -Artificial modification of landscape -Dam construction Land Subsidence: Withdrawal of too much groundwater - Over pumping fluids such as oil, natural gas, water, groundwater, etc. decreases fluid pressure causing rocks to subside Global warming • Rise in temperature: habitat loss • Melting glacier • Rising sea level and flooding • Impact on wildlife, forests, and food crops • Destroys many ecosystem • Hurricane • Coastal erosion
Factors Affecting Population (cont.2)
The demographic transition • A stable pre-industrial state of high birth and death rates changes to a stable post-industrial state of low birth and death rates
According to the Global Footprint Network, humanity current ecological footprint is already estimated to be over 20 % larger than what the planet can sustain/support. • What does this mean?
This means humans are already consuming the planet's renewable resources faster than they can be replenished by natural ecosystem
Factors Affecting Pollution (cont.1)
Total fertility rate • Total fertility rate (TFR) = the ability to bring forth babies Causes of decreasing TFR: Factors affecting population Fertility rates drop when women gain access to contraceptives, family planning programs, and educational opportunities Women with little power have unintended pregnancies - Two-thirds of the world's illiterate are women
