Population | 人口

📚 Population | 人口

Population is a fundamental concept in economics that examines how the size, growth, and structure of a human population interact with economic development, resource availability, and living standards. For IGCSE Economics students, understanding population dynamics is essential for analysing issues such as employment, poverty, taxation, and sustainable development.

人口是经济学中的一个基本概念，研究人口的规模、增长和结构如何与经济发展、资源可获性以及生活水平相互作用。对于 IGCSE 经济学学生而言，理解人口动态对于分析就业、贫困、税收和可持续发展等问题至关重要。

1. World Population Trends | 世界人口趋势

The world population reached 8 billion in November 2022, having grown from approximately 2.5 billion in 1950. This rapid increase is often referred to as the ‘population explosion’, and it has occurred at very different rates across regions.

世界人口于 2022 年 11 月达到 80 亿，而 1950 年时约为 25 亿。这种快速增长通常被称为”人口爆炸”，并且在不同地区以截然不同的速度发生。

Global population growth rates have actually slowed since the 1960s, when the annual growth rate peaked at around 2.1%. Today the rate stands at roughly 1.0% per year. However, the absolute number of people added each year remains high because the base population is so large, adding about 70-80 million people annually.

实际上，自 20 世纪 60 年代年增长率达到约 2.1% 的峰值以来，全球人口增长率已经放缓。目前这一比率约为每年 1.0%。然而，由于人口基数庞大，每年新增的绝对人数仍然很高，每年大约增加 7000 万至 8000 万人。

Regionally, the fastest growth is now occurring in Sub-Saharan Africa and parts of Asia, while many European countries and Japan face stagnating or declining populations. These contrasting trends create different economic challenges for each region, from youth unemployment in growing populations to labour shortages in shrinking ones.

从地区来看，目前增长最快的是撒哈拉以南非洲和亚洲部分地区，而许多欧洲国家和日本则面临人口停滞或减少。这些截然不同的趋势给各地区带来了不同的经济挑战，从人口增长地区的青年失业到人口减少地区的劳动力短缺。

2. Causes of Population Growth | 人口增长的原因

Population change is determined by three main factors: the birth rate, the death rate, and net migration. The natural rate of population growth is calculated as the birth rate minus the death rate.

人口变化由三个主要因素决定：出生率、死亡率和净移民。人口自然增长率等于出生率减去死亡率。

Natural population growth rate = Birth rate − Death rate

人口自然增长率 = 出生率 − 死亡率

Birth rates tend to be high in less developed countries (LDCs) for several reasons. Children may be seen as an economic asset who can work and support the family. There is often limited access to contraception and family planning services. Cultural and religious norms may encourage large families. Additionally, high infant mortality rates mean parents choose to have more children to ensure that some survive to adulthood.

出生率在欠发达国家往往较高，原因有几个。孩子可能被视为经济资产，可以劳动并补贴家庭收入。人们通常难以获得避孕药具和计划生育服务。文化和宗教规范可能鼓励大家庭。此外，高婴儿死亡率意味着父母选择生育更多孩子以确保一些能够存活到成年。

Death rates have fallen dramatically in most countries due to improvements in healthcare, sanitation, nutrition, and medical technology. Vaccination programmes, cleaner water supplies, and better maternal care have all contributed to longer life expectancy. This decline in death rates generally happened before the fall in birth rates, creating a period of rapid population growth known as the ‘demographic transition’.

死亡率在大多数国家大幅下降，原因是医疗保健、卫生设施、营养和医疗技术的改善。疫苗接种计划、更清洁的供水和更好的孕产妇护理都有助于延长预期寿命。死亡率的下降通常先于出生率的下降，从而形成了一段被称为”人口转型”的人口快速增长时期。

Net migration is the difference between immigration (people moving into a country) and emigration (people leaving a country). Countries with strong economies, such as the UK and Germany, often experience net inward migration, which adds to the population and, importantly, tends to increase the proportion of working-age people. Countries experiencing economic hardship or conflict may see net outward migration, which can drain the economy of skilled workers.

净移民是移入移民（进入一个国家的人）与移出移民（离开一个国家的人）之间的差额。经济强劲的国家，如英国和德国，通常经历净移入移民，这会增加人口，并且重要的是往往会提高劳动年龄人口的比例。经济困难或冲突的国家可能出现净移出移民，从而流失技术工人，削弱经济。

3. Population Structure | 人口结构

The population structure describes the composition of a population by age and gender, typically represented by a population pyramid. The shape of the pyramid reveals a great deal about a country’s stage of development and its future economic challenges.

人口结构描述人口按年龄和性别的构成，通常用人口金字塔来表示。金字塔的形状可以揭示一个国家所处的发展阶段及其未来的经济挑战。

A broad-based pyramid, with many young people, indicates a high birth rate and is typical of less developed countries. A narrow-based or column-shaped pyramid indicates a low or declining birth rate and is typical of developed countries. In many developed countries the pyramid is actually becoming top-heavy because life expectancy continues to rise while birth rates remain low.

宽基底的金字塔意味着大量年轻人，表明出生率高，是欠发达国家的典型特征。窄基底或柱状的金字塔表明出生率低或下降，是发达国家的典型特征。在许多发达国家，由于预期寿命不断延长而出生率保持在低位，金字塔实际上正变得”头重脚轻”。

An important concept related to population structure is the dependency ratio, which measures the proportion of the population that is economically dependent (under 15 and over 65) relative to those of working age (15–64).

与人口结构相关的一个重要概念是抚养比，它衡量经济上受抚养人口（15 岁以下和 65 岁以上）相对于劳动年龄人口（15–64 岁）的比例。

Dependency ratio = (Population aged 0–14 + Population aged 65+) ÷ Population aged 15–64 × 100

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