環(huán)境專業(yè)英語 02_population

1、B Y H U A N G L E IAs of 15 February 2012, the world population is estimated by the United States Census Bureau to be 6.994 billion.And it is currently growing at an annual rate of 1.2%, or 77 million people per year.1. Shanghai14,608,512China 2. Buenos Aires13,076,300Argentina3. Mumbai12,691,836Ind

2、ia4. Karachi11,624,219Pakistan5. Mexico City11,285,654Mexico6. Istanbul11,174,257Turkey7. Delhi10,927,986India8. Manila10,444,527Philippines9. Moscow10,381,222Russia10. Dhaka10,356,500Bangladesh11. Seoul10,349,312South Korea12. Sao Paulo10,021,295BrazilThe explosion of world population is an outgrow

3、th of the industrial age, and three key factors are to blame: increased food productiondisease controlbetter sanitationThe crisis of population expansionFood shortagesIncreased competitionResource shortagePollutionIncreased costsLack of freedomDevelopment restrictionsResourcesA resource is a source

4、or supply from which benefit is produced. Typically resources are materials or other assets that are transformed to produce benefit and in the process may be consumed or made unavailable. From a human perspective a natural resource is anything obtained from the environment to satisfy human needs and

5、 wants.ResourcesAbiotic resources comprise non-living things (land, water, air, minerals,)Biotic resources are obtained from the biosphere (Forests, animals, Minerals such as coal and petroleum are sometimes included in this category because they were formed from fossilized organic matter, though ov

6、er long periods of time).ResourcesNon-renewable ResourcesRenewable resourcesResourcesNon-renewable Resources are formed over very long geological periods. Minerals and fossils are included in this category. Since their rate of formation is extremely slow, they cannot be replenished once they are dep

7、leted. Out of these, the metallic minerals can be re-used by recycling them, but coal and petroleum cannot be recycled.Renewable resources can be replenished or reproduced relatively quickly. The highest rate at which a resource can be used sustainably is the sustainable yield. Some resources, like

8、sunlight, air, and wind, are called perpetual resources because they are available continuously, though at a limited rate. Their quantity is not affected by human consumption. Many renewable resources can be depleted by human use, but may also be replenished, thus maintaining a flow. Some of these,

9、like agricultural crops, take a short time for renewal; others, like water, take a comparatively longer time, while still others, like forests, take even longer. Characteristics of Natural Resources of ChinaExamplesOne of the worlds best-studied predator-prey relationships is the moose and wolf popu

10、lation of Isle Royale National Park in Lake Superior. Without the wolves, the moose would overgraze the islands vegetation. Without the moose, the wolves would die. The first scientists who studied the issue thought that the wolves would eventually overpopulate and kill all the moose calves, then di

11、e from famine. Disease and environmental factors have limited the wolf population naturally.Easter Island has been cited as an example of a human population crash. When fewer than 100 humans first arrived, the island was covered with trees with a large variety of food types. In 1722, the island was

12、visited by Jacob Roggeveen, who estimated a population of 2000 to 3000 inhabitants with very few trees, a rich soil, good climate and all the county was under cultivation. Half a century later, it was described as a poor land and largely uncultivated. The ecological collapse which followed has been

13、variously attributed to overpopulation, slave traders, European diseases (including a smallpox epidemic which killed so many so quickly, the dead were left unburied and a tuberculosis epidemic which wiped out a quarter of the population), social upheaval and invasive species (such as the Polynesian

14、rats which may have wiped out the ground nesting birds and eaten the palm tree seeds). Whatever the combination of factors, only 111 inhabitants were left on the island in 1877. The question of how many humans the island could realistically support never seems to have been answered.The carrying capa

15、city of a biological species in an environment is the maximum population size of the species that the environment can sustain indefinitely, given the food, habitat, water and other necessities available in the environment.MathematicsThe Lotka-Volterra equations are simple mathematical model of popul

16、ation dynamics which show how in a closed system, like that of the wolves and moose on Isle Royale, limited prey will cause the predator population to decline rapidly. An extended example can be used where multiple species are competing for the same resources, or single species feed on multiple prey

17、.HumansThe application of the concept of carrying capacity for the human population has been criticized for not successfully capturing the multi-layered processes between humans and the environment, which have a nature of fluidity and non-equilibrium, and that it often has a blame-the-victim framewo

18、rk.Ecological footprintOne way to estimate human demand compared to ecosystems carrying capacity is Ecological Footprint accounting. Ecological footprintRather than speculating about future possibilities and limitations imposed by carrying capacity constraints, Ecological Footprint accounting provides empirica