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  3. U.S. PopulationPresent Situations of U.

U.S. PopulationPresent Situations of U.

游客2023-09-02  30
问题                                         U.S. Population
Present Situations of U.S. Population
    The U.S.—the most populous of today’s developed countries—bas one of the highest population growth rates of the industrialized nations: about one percent annually. This adds some 2.5 million people every year—equivalent to a new city the size of San Diego—which is by far the largest numerical increase of any developed country. By the end of 1994, the U.S. population had climbed to 262 million, up from 203 million in 1970. The change stands in sharp contrast with Europe which today adds less than a million people per year to a population of about 728 million and Japan’s addition of 0.3 million to a total of 125 million.
    Immigration now contributes roughly a third of the annual U.S. increase, although natural increase, or births minus deaths, remains substantial at about 1.7 million per year. This is in part the consequence of a younger age distribution resulting from the post-war baby boom (1946-1964), but U.S. fertility (生育力) has also been among the highest of the industrialized countries. The U.S. TFR ( the total fertility rate, defined as the average number of children women will bear in their lifetime) remained at about 1.8 from the mid-1970s to the latter 1980s, when it began rising to 2.1 in 1991. The U.S. TFR has since receded slightly, dropping to about 2.0 in 1993.
    The relatively high U.S. fertility is one of this country’s most striking demographic (人口统计学的) features. Should the present rate persist, the country would remain at or near the replacement level to avoid population decline as in Europe. Although fertility levels do vary among ethnic groups, the TFR for U.S. non-Hispanic white women in 1992 was nonetheless 1.8; for blacks, it was 2.4; Asian and Pacific Islanders, 1.9; American Indians, 2.2; and Hispanics 3.0.
National Trends
    The U.S. population is undergoing at least two major shifts: a significant change in its geographic distribution and a similarly important change in ethnic composition. Immigration— accounting for a third of the present annual growth—is also an undeniable factor. The stream of immigrants into the U.S. is highly directed towards but six of the 50 states (California, with 261,000 legal immigrants in 1993; New York 151,000; Texas 67,000; Florida 61,000; New Jersey 50,000; and Illinois 47,000). Within these, moreover, the flow is concentrated within but a few metropolitan areas.
Shifts in Geographic Distribution
    The balance of population is shifting rapidly to the South and West. The Northeast and Midwest have experienced a continuous loss of population to the South and West by migration from other areas of the U.S. These two "sun-belt" regions have also received a higher influx of immigrants.
    From 1990 to 1993, the Northeast and Midwest experienced a net loss of 367,000 residents through migration to other parts of the country while gaining 260,000 immigrants from abroad. The South gained 471,000 migrants from the balance of the U.S. and another 180,000 from outside the country. The West actually lost population because of migration to other regions, because of the numerical dominance of the state of California in the region. It is likely that the loss of jobs in California in defense-related employment was responsible for this unexpected mm of events. The South and West received no fewer than 500,000 net immigrants from abroad, just over half of which were to California alone.
Changes in Ethnic Composition
    One-fourth of the present population of the U.S. is now composed of racial minorities, which are defined as anyone who is not white and non-Hispanic. In the next 50 years that fraction will grow to nearly half the total, according to recent projections. The Hispanic population is projected (预测) by the Census Bureau to rise from 22.5 million in 1990 to just under 90 million by 2050, due to the combination of immigration and higher fertility. If that projection proves true, Hispanics would increase their share of the total population to about 22% from 9% in 1990. Asian and Pacific Islanders, although a lower fertility group, would rise from 7.6 million in the 1990 Census to 41 million by 2050. Much slower growth is projected for the black population: from 30.6 million in 1990 to 62 million by mid-century. The slower pace of growth in this group is based upon present, relatively low levels of immigration—a situation which could well change in time.
    Population prospects differ regionally in yet another, often-overlooked way: the birth rate. Due to both higher birth rates and younger populations, births outnumber deaths by a wider margin in the "sun-belt" states of the South and West than in the North and East. From 1990 to 1993, for example, there were only 124 births per 100 deaths in Pennsylvania while there were 260 in California and 336 in Utah. The majority of "frost-belt" states have TFRs below the replacement level; the opposite is true in the South and West, in part because immigrants to the U.S. have generally higher fertility rates. This means, of course, that the northern states could ultimately experience population decline due to low fertility rates which may or may not be offset by migration. While migration trends can change rapidly, fertility rates tend to be comparatively stable.
Conclusions and Consequences of Population Increase
    What are the consequences of population growth both for the U.S. and for the world as a whole? In the recent past, the primary concern for developing countries--where virtually all the growth is found—dealt with matters of adequate food supply. Thus far, food production has generally kept pace with population growth in all regions except Africa. But what about the future, when world population will inexorably (不可避免的) increase?
    Meeting this goal, however, depended upon increasing land under cultivation and also raising production per acre or hectare to about the level of a development farm in Asia—i.e., expanding the scope of the agricultural "Green Revolution". To achieve this level of production will require significant inputs of capital and fertilizers, which opens the larger issue of "sustainable development". Can developing countries modernize agriculture, industrialize and raise Gross National Product without excessive harm to the environment? There are other obvious concerns that go beyond simple food production, including food distribution and storage and associated costs, local and regional availability of freshwater, energy demands, land use, land, air, and water quality. The ramifications of these issues in the face of continued, rapid growth in world population will pose profound policy questions for those who govern the world of tomorrow--as they do indeed today.
    For the U.S., the key issues are these: The Census Bureau projections call for an addition of about 130 million people by 2050 if current trends continue, with modest growth after that. We may also reasonably assume that immigration will continue to contribute significantly to the projected increase. The U.S. has a long history of immigration and many groups, including business interests, would lobby strenuously to maintain it as an element of expanding markets. In fact, the most recent revision to U.S. immigration law raised the number of allowed immigrants from about 550,000 to about 800,000 per year, including refugees.
    The primary impact of U.S. population growth will be felt in the areas of the country where in recent years growth has tended to concentrate. For the most part, this can be divided into two categories: (1) high-growth states such as Florida, California, and Texas, and (2) smaller metropolitan areas which have experienced accelerated growth in recent years. Cities such as Charlotte, North Carolina, have emerged as significant centers of growth with expanding employment markets.
    Although predicting the future is always risky, we can be fairly certain of the general trends now expected in global population in the next few decades. The world will add billions to its population, through additions made almost exclusively in the world’s poorer nations. This can only be expected, since developing countries already represent most of the world’s population. The United States, as well, faces the new century as the only remaining industrialized country with high-impact growth in its future. And, the United States has never lived in isolation from the rest of the world: Over half of its anticipated growth is expected to come in the future from immigration, following a well-established, historical pattern. These anticipated changes, that now seem almost inevitable, loom (隐现) large as the backdrop against which today’s policy choices are to be made, both in and out of government. [br] The primary concern for developing country in the past dealt with matters of______.
选项
答案 adequate food production/supply
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