首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
World Population Growth and Distribution The United Nations, an accepted authority on population levels and trends, estimate
World Population Growth and Distribution The United Nations, an accepted authority on population levels and trends, estimate
admin
2010-05-09
43
问题
World Population Growth and Distribution
The United Nations, an accepted authority on population levels and trends, estimates that the world population reached 6 billion in 1999, and is increasing annually by more than 77 million persons. The rate of increase, 1.3 percent per year, has fallen below the peak rate of 2 percent per year attained by 1970. By the late 2040s, the UN estimates, the growth rate will have fallen to about 0.64 percent annually, at which time more than 50 countries will experience negative growth.
A. Past and Present Growth
Estimates of world population before 1900 are based on fragmentary (零散的) data, but scholars agree that, for most of human existence, long-run average population growth approached approximately 0.002 percent per year, or 20 per million inhabitants. According to UN estimates, the population of the world was about 300 million in the year AD 1, and it took more than 1,500 years to reach the 500 million mark. Growth was not steady but was marked by oscillations (摆动) dictated by climate, food supply, disease, and war.
Starting in the 17th century, great advances in scientific knowledge, agriculture, industry, medicine, and social organization made possible rapid acceleration in population growth. Machines gradually replaced human and animal labor. People slowly acquired the knowledge and means to control disease. By 1900 the world population had reached 1.65 billion, and by 1960 it stood at 3.04 billion.
Beginning about 1950, a new phase of population growth was ushered in when famine and disease could be controlled even in areas that had not yet attained a high degree of literacy or a technologically developed industrial society. This happened as a result of the modest cost of importing the vaccines (疫苗), antibiotics, insecticides, and high-yielding varieties of seeds produced since the 1950s. With improvements in water supplies, sewage-disposal facilities, and transportation networks, agricultural yields increased, and deaths from infectious and parasitic diseases greatly declined. Life expectancy at birth in most developing countries increased from about 35~40 years in 1950 to 66 years by 2000. The rapid decline in deaths among people who maintained generally high fertility rates led to annual population growth that exceeded 3.1 percent in many developing nationsa--rate that doubles population size in 23 years.
B. Regional Distribution
As of 2000, 1.2 billion people lived in the developed nations of the world, and 4.9 billion people lived in the less-developed countries. By region, over half the world’s population was in East and South Asia; China, with 1.3 billion inhabitants, and India, with some 1 billion, were the dominant contributors. Europe and the countries of the former USSR contained 14 percent, North and South America made up 14 percent, Africa had 13 percent, and the Pacific Islands had about 1 percent of world population.
Differences in regional growth rates are altering these percentages over time. Africa’s share of the world population is expected to more than double by the year 2025. The population of South Asia and Latin America is expected to remain nearly constant; in other regions, including East Asia, the population is expected to decline appreciably. The share of the present developed nations in world population--20 percent in 2000--is expected to fall to 15 percent by 2025. Nine out of every ten persons who are now being added to the world’s population are living in the less-developed countries.
C. Urban Concentration
As a country develops from primarily an agricultural to an industrial economy, large-scale migration of rural residents to towns and cities takes place. During this process, the growth rate of urban areas is typically double the pace of overall population increase. Some 29 percent of the world population was living in urban areas in 1950; this figure was 43 percent in 1990, and is projected to rise to 50 percent by the year 2005.
Urbanization eventually leads to a severe decline in the number of people living in the countryside, with negative population growth rates in rural areas. Rapid growth of overall population has deferred this event in most less-developed countries, but it is projected to occur in the early decades of the 21st century.
Most migrants to the cities can be assumed to have bettered themselves in comparison to their former standard of living, despite the serious problems of overcrowding, substandard housing, and inadequate municipal services that characterize life for many arrivals to urban centers. Dealing with these conditions, especially in very large cities, presents massive difficulties for the governments of less-developed countries.
D. Population Projections
Most of the potential parents of the next two decades have already been born. Population projections over this interval can, therefore, be made with reasonable confidence, barring catastrophic changes. Beyond two decades, however, uncertainties about demographic magnitudes and other characteristics of human societies build up rapidly, making any projections somewhat speculative.
Projections issued in 2000 show the world population increasing from 6.1 billion in 2000 to 7.9 billion in 2025 and 9.3 billion in 2050. "High" and "low" projections for 2025 are 8.4 billion and 7.5 billion respectively. The average world birth rate is projected to decline from the 1990 level of 26 per 1,000 to 22 per 1,000 at the end of the century and to 17.6 per 1,000 in 2025. Because of the expanding share of the population at high-mortality ages, the average world death rate is expected to decline only slightly; from 9 per 1,000 in 1990 to 8.4 in 2025. Average world life expectancy, however, is projected to rise from 65 years in 1990 to 71.3 years in 2025.
Wide variations in population growth will undoubtedly persist. In the developed world, population growth will continue to be very low and in some nations will even decline. Western Europe as a whole is projected to have a declining population after 2000. U.S. Census Bureau projections, assuming middle fertility and mortality levels, show U.S. population increasing from 250 million in 1990 to 349 million in 2025 and 420 million in 2050. Thereafter, growth would be virtually zero.
POPULATION POLICIES
Government population policies seek to contribute to national development and welfare goals through measures that, directly or indirectly, aim to influence demographic processes--in particular, fertility and migration. Examples include statutory minimum ages for marriage, programs to promote the use of contraception, and controls on immigration. (When such policies are adopted for other than demographic reasons, they can be termed implicit policies.)
A. Population Policy in the United States
The early immigrants to North America found a vast continent with a relatively small indigenous population. Overcrowding was incomprehensible because of the expanse of land to the west.
In the mid-20th century, as the rest of the world awakened to the potential crisis brought on by unchecked population growth, the U.S. government examined the possible impact of overpopulation in the nation. The President’s Commission on Population Growth and the American Future began a two-year study in 1970. Submitted to President Richard M. Nixon in 1972, it welcomed the prospect of zero population growth in the U.S., but did not propose that the government take strong measures to attain it. The commission did, however, advocate education on family planning and widely available access to contraception and abortion services. Primarily because of this, the president rejected the commission’s recommendations.
B. Population Policies in Developed Nations
European countries did not address the issue of a national population policy until the 20th century. Subsidies were granted to expanding families by such disparate nations as the United Kingdom, Sweden, and the USSR. The Italian Fascists in the 1920s and the National Socialists (Nazis) in Germany during the 1930s made population growth an essential part of their doctrines.
Japan, with an economy comparable to those of the European nations, was the first developed country in modem times to initiate a birth-control program. In 1948 the Japanese government formally instituted a policy using both contraception and abortion to limit family size.
C. Population Policies in the Third World
In 1952 India took the lead among developing nations in adopting an official policy to slow its population growth. India’s stated purpose was to facilitate social and economic development by reducing the burden of a young and rapidly growing population. Surveys to ascertain contraceptive knowledge, attitude, and practice showed a high proportion of couples wishing no more children. Few, however, practiced efficient contraception. Family-planning programs were seen as a way to satisfy a desire for contraception by a large segment of the population and also to confer health benefits from spacing and limiting births.
Asia’s lowered growth rate can be attributed mainly to the stringent (严厉的) population policies of China. Although it has a huge population, China has successfully reduced both fertility and mortality. The government has recently been advocating one-child families to lower the nation’s growth rate.
The developed nations will make more efforts to increase their population growth.
选项
A、Y
B、N
C、NG
答案
C
解析
在小标题B.Population Policies in Developed Nations下面谈到一些发达国家的鼓励生育的政策,但没有给出任何暗示表明发达国家将做出更大的努力来增加他们的人口,因此此题的答案为NG。
转载请注明原文地址:https://kaotiyun.com/show/R2KK777K
0
大学英语六级
相关试题推荐
NowwetraveltothenorthcentralpartoftheUnitedStates.WeareinthestateofSouthDakota.Thelandisbigandmostlyfl
Fromthepassage,whichisthemaininfluencefactorinthefuture?Whatdoestheword"upheaval"(Line1,Para.3)mostprobab
Fromthepassage,whichisthemaininfluencefactorinthefuture?Accordingtotheauthor,whichofthefollowingisTRUEabo
NearlyeveryonehasrealizedthatMicrosoftbuyingHotmailhasillustratedtheparadoxofInternet.Theprogramaimedatcreati
NearlyeveryonehasrealizedthatMicrosoftbuyingHotmailhasillustratedtheparadoxofInternet.Socialnetworkinghasitse
______(我订阅这份杂志的主要原因)istokeepabreastofadvancesinscience.
A、£5.B、£30.C、£50.D、£55.BHowmuchwillthewomanpayifshewantstotryfortwomonths?本题属于较难的数字题,要经过运算之后才能得山结论。综合男士所说的If
A、Thenewapartmentischeaper.B、Shelikestolistentotheradio.C、Thepresentoneistooexpensive.D、Sheneedsaquieterpl
A、Anenvironmentprotector.B、Avisitingscholar.C、Anengineeronconstruction.D、AtouristwhohavevisitedAlaska.B该题问“讲话者的职
Itisexcitedtoapplyforajobthatreallyappealstoyou.【S1】______Inmakingyourapplication,therearethenum
随机试题
患者,男,20岁,以呼吸困难半年,不能平卧1周来诊。查体:BP110/70mmHg,颈静脉怒张,心界明显向左扩大,心音不等,心律绝对不齐,HR110/min。肝大肋下5cm,双下肢水肿。扩张型心肌病左、右室同时衰竭时,与临床症状和体征最有关的因素是
平原河流丁坝宜用()。
下列行为违反《商业银行法》的有()。
唯物辩证法认为,整体处于统帅的决定地位,部分服从和服务于整体。部分是整体中的部分,部分离不开整体,离开了整体,部分也就不称其为部分。因此,大局的走向决定局部的命运。正因为大局在事物发展中起着主导的决定作用,找准全局性、大局性的问题,也就抓住了工作的重点和中
福勒和布朗根据教学所关注的焦点问题,把教师的成长分为()阶段。
现阶段我国教育目的的重点是()
一组记录的关键字为{45,78,55,37,39,83},利用堆排序初始时的堆为()。
Longbeforetheneweconomymadecatchwordsofspeed,customization,supplychainmanagement,andinformationsharing,Spanishc
瀑布模型是最常用的传统软件开发模型。它的特点之一是(1)。根据国家标准GB 8566-88《计算机软件开发规范》的规定,软件开发流程分为8个阶段,即可行性研究和计划、需求分析、概要设计、详细设计、实现、组装测试、确认测试、使用和维护。实现阶段要完成的工作之
在数据处理中,其处理的最小单位是()。
最新回复
(
0
)