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世界决定视界，视界决定世界 擦亮双眼看世界 Global Perspective See Globally via Global Perspective 本期导读：人口学（Demography）是研究人类出生、死亡、迁移的一门学科。同时借由这些人口的增长或缩减之现象，进一步探讨人口增减变动因素的影响或原因。 人口依据年龄具有下列几项的区分: 依赖年龄:是指0~14岁至65岁以上的人口。泛指幼年及老年人口。 生产年龄:指15岁至64岁之人口。泛指青年及壮年人口。 年龄中层:即是年龄中位数，足以将年龄区分成两半。 人口依赖比:又称为扶养比，是生产年龄÷依赖年龄×100%所得之数值。 人口性别年龄金字塔图：用以区分人口性别年龄与结构的一张图表，以表示人口之性别年龄的分布状况。 年龄比例:指不同数量的年龄所占的比例，即是各种年龄阶层的结构 性别比例:又称为性别比，是一个衡量人口男女性别比例的指标。当大于100，即是男性多于女性；小于100反之。 人口结构的类型主要有： 1增进型:即低金字塔，呈现下宽上窄的结构。多存在于低开发国家。 2稳定型:人口结构稳定，发展均衡。发生在发展中国家。 3减退型:即倒金字塔，呈现上宽下窄的结构。存在发达国家。
人口增减：具有两种主要的人口增减模式。 自然增减：是指一个地区内的人口出生与死亡所造成人口增加或减少的情形，为自然增减。人口的自然增减现象通常涉及到相关的经济与社会因素的现象。如国家经济发展度对自然增减的影响力。 社会增减：指某个地区内人口流出会或流入迁移动作，所造成一个社会当中的人口增减的影响。社会增减牵连到输出国与输入国之间的经济发展差距和社会政治等影响之外，也包括如宗教、战争、文化等因素的影响。 人口迁移：指居住地点的暂时或永久性改变。同时涉及了相关的因素构成迁移的动力与原因。 内部迁移：指在一国国内的县市里的迁移，通常经济是最大的影响因素，其反映了生活方式的流动与水准不同。(例如乡村迁入到都市的内部迁移)。 国际迁移：指跨国国际间的居住地点流动。通常，在接受国际迁移的国家，如果发生失业率高且住宅不足等情况，会造成“反移民”的风朝，进一步对当地社会秩序产生动荡与不安。 少子化是指生育率降低，老人人口高达7%是高龄化社会，导致幼年人口比例逐渐减少的现象。少子化代表着未来劳动人口可能逐渐变少，对于社会结构、经济发展等各方面都会产生重大影响。如果新一代增加的速度远低于上一代自然死亡的速度，更会造成人口不足，所以少子化是许多国家（特别是发达国家）非常关心的问题。 “少子化”原为日文，由于日本是世界上经济发展快速的国家之一，国家开发程度较高，社会转型进入工商业的现象不仅明显而广泛，已婚家庭与生育面对紧张的工作环境时，常减退育儿的动机，并错过生育的机会，也因此较早面临少子化的问题，相关研究亦较为深广，故后来逐渐遇到相同问题的中国等汉字通行区，便直接引入此外来语作为指称。 由于发达国家的生育率与死亡率几乎都低，所以从相对的角度来看，少子化就意谓著高龄人口相对变多，即高龄化，因此这两个常常是指相同现象的名词也有人将其合而为一，变成“少子高龄化”，近年来随着经济多元发展，一些生活水平大幅提高的发展中国家在还未达到发达国家的门槛也开始出现了可能是“高龄化”或“少子化”甚至两种同时出现的现象，少子化也不再仅限于东亚，甚至在鼓励生育的保守国家亦有面临着此问题，显见此种现象已成为全球的社会问题。
Global population skews male, but UN projects parity between sexes by 2050 联合国预计全球人口整体性别比将趋均衡
小编注：译文部分仅供参考；下面共享的信息，整理自皮尤研究中心网站；欢迎分享本公众号优质文章，并推荐给需要的朋友，感谢支持。 Globally, the number of males has exceeded the number of females since the mid-1960s. But by 2050, the worldwide sex ratio is expected to even out, according to recently released population projections from the United Nations. As of 2021, there were about 44 million more males than females in the global population. But that difference is expected to disappear as a result of several different demographic trends.
In the coming decades, the world population is expected to age due to a combination of declining fertility (a smaller share of the world’s population will be young) and people living longer (a larger share of the world’s population will be old). Between 1950 and 2021, the median global age rose from 22 to 30. By 2050, the UN projects the median global age will surpass 35.
When a large share of a population is young, it tends to skew male because more boys are born than girls. This pattern is exacerbated in countries where sex-selective abortions and female infanticide contribute to imbalanced sex ratios at birth. In 2021, the global sex ratio at birth was 106 male births per 100 female births. Gender inequalities also make girls and women more vulnerable to poor health, often putting them at higher risk of death, including from complications during and following pregnancy and childbirth. However, in most countries, females have lower mortality rates after birth and live longer than males, on average. Higher male mortality has been associated with behavioral factors and genetic differences. In addition, more males than females have died due to the COVID-19 pandemic. Because of these patterns, females outnumber males at older ages. In 2021, women comprised 56% of the global population ages 65 and older, including 59% in Europe and Northern America. Their share of the global 65-and-older population is projected to be 54% by 2050. As populations age, they are more likely to become majority female. Not only does the UN project parity between the sexes by 2050, it projects that females will begin to outnumber males in the decades after 2050. Sex ratios vary widely The countries with the biggest male-to-female ratios today are Qatar (266 males per 100 females), the United Arab Emirates (228) and Bahrain (164). In several Persian Gulf countries, these wide sex imbalances are primarily due to large immigrant populations of largely male temporary workers. For example, according to UN estimates, 79% of Qatar’s 2019 population was born elsewhere, and among the foreign-born population, 83% were male.
In many former Soviet Union republics, the reverse is true. The former USSR has been predominantly female since at least World War II, when millions of men died in battle. For example, in the territory that is now Russia, there were just 77 males per 100 females in 1950. That number rose steadily in subsequent decades, climbing to 88 by 1995 before starting to decline again. Several other countries from the former Soviet Union have seen similar patterns, and in 2021, they accounted for six of the 10 nations with the highest ratio of females to males. Even within the same country, sex ratios can differ widely by age. For example, Armenia is the most heavily skewed country toward females (82 males per 100 females), but there are still more newborn boys than girls. In fact, for every 100 girls born in Armenia, 110 are boys – the world’s sixth starkest sex ratio at birth in favor of boys. Other places with overall sex ratios that skew heavily female include Guadeloupe, Martinique, Hong Kong and the U.S. Virgin Islands. The United States has had more females than males since 1946, according to the U.S. Census Bureau. In 2021, the population sex ratio in the U.S. was 98 males per 100 females. By 2050, it is expected to be 99. The number of majority-male countries will decline by 2050 In 2021, males outnumbered females in 86 countries. That figure is expected to decline to 67 countries by 2050 as an increasing number of majority-female populations emerge. Within countries where males are expected to continue outnumbering females in 2050, the UN still projects a more balanced sex ratio in the coming decades. A recent Pew Research Center report took a closer look at the sex ratio at birth in India, specifically. India’s artificially wide ratio of baby boys to baby girls – which arose in the 1970s from the use of prenatal diagnostic technology to facilitate sex-selective abortions – now appears to be narrowing. This follows years of government efforts to curb sex selection, including a ban on prenatal sex tests and a massive advertising campaign urging parents to “save the girl child,” and coincides with broader social changes such as rising education and wealth. Projections describe how populations will change if their underlying input data are accurate and their assumptions about future trends (e.g., that fertility will decline in high-fertility countries) are correct. However, unexpected events like war, famine and disease may produce different outcomes and may alter the world’s gender balance by causing a greater number of deaths for males or females and by affecting migration trends of individual countries. |
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