Population pyramids: Powerful predictors of the future - Kim Preshoff

人口金字塔: 強而有力的未來預測 — 金‧浦曉夫 (Kim Preshoff)

Transcriber: Jessica Ruby Reviewer: Caroline Cristal

譯者: Sunyuching Sun 審譯者: Regina Chu

Russia, with the largest territory in the world,

俄羅斯—全世界領土最大的國家

has roughly the same total population as Nigeria,

總人口和奈及利亞大致相同

a country 1/16 its size.

但奈及利亞面積 只有俄羅斯的 16 分之 1 大

But this similarity won't last long.

但這個相似處不會持續很久

One of the populations is rapidly growing,

因為一國的人口急速成長

while the other is slowly declining.

而另一國的人口緩慢的衰退中

What can this tell us about the two countries?

關於這兩個國家 這個情形告訴我們什麼？

Population statistics are some of the most important data

人口統計是最重要的數據之一

social scientists and policy experts have to work with.

社會學家和政策決策者依此來做決定

But understanding a country's situation

但是，了解一個國家的情形

and making accurate predictions

和作準確的預測

requires knowing not just the total size of the population

需要知道不只是人口的數量

but its internal characteristics,

還必須知道它的內部特性

such as age and gender distribution.

例如：年齡和性別分布

So, how can we keep track of all that data

所以，我們要如何追蹤所有的數據

in a way that makes it easy to comprehend?

並讓它容易理解？

Complex data is more easily interpreted

複雜的數據比較容易解釋

through visualization,

藉由視覺化呈現

and one of the ways that demographers represent

其中一種人口學家用來代表

the internal distribution of a population

內部人口分布的方式

is the population pyramid.

是人口金字塔

Here, the data is divided by gender

數據是以性別來區分

with females on one side and males on the other.

女性在一邊，男性在另一邊

The population numbers are shown

人口數量是依照

for each five-year age interval,

五歲為一年齡區間

starting from 0-4

從 0-4 歲開始

and continuing up to 100 and up.

到 100 歲以上

These intervals are grouped together

這些年齡區間集合起來

into pre-reproductive (0-14),

分為幼年期 (0-14歲)

reproductive (15-44),

青壯年期 (15-44歲)

and post-reproductive years (45 and up).

和老年期 (45歲以上)

Such a population pyramid can be a powerful predictor

這樣的人口金字塔可以是 非常準確的預測

of future population trends.

未來的人口趨勢

For example,

舉例來說

Rwanda's population pyramid shows it to be a fast-growing country,

盧安達的人口金字塔顯示 它是一個人口快速成長的國家

with most of the population

大多數的人口

being in the youngest age groups at the bottom of the pyramid.

為金字塔底部的年幼族群

The number will grow rapidly in the coming years.

人口將會快速增加

As today's children reach their reproductive years

當孩童長大到了壯年時期

and have children of their own,

而且有了他們的下一代

the total population is almost certain to double

在未來數十年內 總人口數將會成長近兩倍

within the next few decades.

For our second example,

第二個例子

let's look at Canada,

我們來看看加拿大

where most of the population is clustered

加拿大大多數的人口集中在

around the middle of the graph.

圖形的中間

Because there are less people

因為越來越少的人口

in the pre-reproductive age groups

在年幼的年齡群組裡

than there are in the reproductive ones,

和壯年期的人口相比

the population will grow more slowly,

人口將會緩慢的成長

as the number of people reaching their reproductive years decreases.

因為未來達到壯年人口的數量將減少

Finally, let's look at Japan.

最後，我們看看日本

Because the majority of its population

大部分的人口

is in its post-reproductive years

為老年人口

and the number of people is smaller

而人口數

at each younger interval,

隨著每個幼年區間遞減

this means that at current rates of reproduction

這表示依照目前的生育率

the population will begin to decline

人口將會下降

as fewer and fewer people reach reproductive age.

因為越來越少人進入青壯年期

Comparing these three population pyramids

比較這三個金字塔

side by side

並排在一起

shows us three different stages

向我們展示三個不同的階段

in a demographic transition,

其人口的轉變

as a country moves from a pre-industrial society

即當一個國家從前工業化的社會

to one with an industrial

轉變成工業化

or post-industrial economy.

或是後工業化的經濟的轉變

Countries that have only recently begun

國家剛開始

the process of industrialization

工業化的過程

typically see an increase in life expectancy

通常會看到人口平均預期壽命的提升

and a fall in child mortality rates

還有幼童死亡率的下降

as a result of improvements

這是改善的結果

in medicine, sanitation, and food supply.

在醫藥、衛生 和食物的供給方面

While birth rates remain constant,

同時，出生率保持一樣

leading to a population boom.

導致人口激增

Developing countries that are farther along

發展中國家更是

in the industrialization process

在工業化的過程

begin to see a fall in birth rates,

會開始看到出生率的下降

due to factors such as

因為一些因素，像是

increased education and opportunities for women outside of child-rearing

教育程度提高，女性除了生育 以外有較多工作機會

and a move from rural to urban living

和從郊區到城市的居住遷移

that makes having large families

這使得大家庭

less economically advantageous.

有較少的經濟優勢

Finally, countries in advanced stages of industrialization

最後，進入先進工業化的國家

reach a point

到了一個階段

where both birth and death rates are low,

出生和死亡率都低

and the population remains stable

人口數保持穩定

or even begins to decline.

或是開始衰減

Now, let's take a look at the projected population pyramids

現在讓我們來看看 預測的人口金字塔

for the same three countries in 2050.

在 2050 年，這三個國家的走勢

What do these tell us

這些圖告訴我們

about the expected changes

關於每個國家的人口

in each country's population,

預期的改變

and what kinds of factors

以及哪些因素

can alter the shape of these future pyramids?

會改變這些未來金字塔的形狀？

A population pyramid can be useful

人口金字塔是有用的

not only as a predictor of a country's future

不只是可以做為國家未來的預測

but as a record of its past.

還可以做為過去的紀錄

Russia's population pyramid

俄羅斯的人口金字塔

still bears the scars of World War II,

還有著世界二次大戰的傷痕

which explains both the fewer numbers of elderly men

它解釋了年長男性為什麼

compared to elderly women

比年長女性少

and the relatively sudden population increase

還有相對突然的人口增長

as soldiers returned from the war

因為士兵在戰爭後返家

and normal life resumed.

重回正常生活

China's population pyramid

中國的人口金字塔

reflects the establishment of the one child policy

反映 35 年以前 一胎化政策的制定

35 years before,

which prevented a population boom

這個政策防止人口數

such as that of Rwanda

像盧安達般激增

but also led to sex-selective abortions,

但是也導致性別篩選的墮胎

resulting in more male children than female children.

造成男孩多於女孩

Finally, the pyramid for the United States

最後，美國的人口金字塔

shows the baby boom that followed World War II.

顯示二戰後的嬰兒潮

As you can see,

如同你所看到的

population pyramids tell us far more

人口金字塔告訴我們

about a country

關於一個國家的成長

than just a set of numbers,

遠超過於一些數字

by showing both where it's been

藉由在一個單一的圖像 顯示出過去和現在的趨勢

and where it's headed

within a single image.

And in today's increasingly interconnected world,

在當今日漸連結的世界

facing issues such as food shortages,

面臨的問題像是食物短缺

ecological threats, and economic disparities,

生態威脅和經濟差距

it is increasingly important

所以現在日益重要

for both scientists and policy makers

對科學家和政策制定者而言

to have a rich and complex understanding

廣泛且深入的了解

of populations and the factors affecting them.

人口和其中的影響因素