臺灣地區人口變遷的原因與結果

台灣地區的現階殷人口變遷始於日據時代中期，約一九二○年前後人口死亡率開始大幅下跌時，至一九八三年時人口淨繁殖率已經迫近於替換水準，在短短不到七十年的時間內完成歐美國家歷史上費時近兩百年的歷程，無論是就數量或速率的變化而言都是一項劇烈的變遷，其影響之深與遠恐非歐美經驗所能比擬，值得利用這個關鍵時刻做點反省與思考。本文引用人口動態的理論檢討過去數十年來的人口變遷，指出日接時代死亡率大幅下跌造成台灣地區的人口快速成長，而且透過一個延後的效應促成光復後的生育率下跌。本文進一步指出戰後的生育率長期大幅下跌必然帶來人口老化的結果，而且生育率下降的速度愈快則人口老化的速度愈快，代換為高峰期人口的就業與職位昇遷問題，也影響到未來老年人口的養老資源及其退休生活。
The population transition in Taiwan has reached the final phase that life expectancy at birth is approaching an asymptote and net reproduction rate is already below the replacement level. It is argued that since the transition takes a shorter period of time to complete than that of the European-American experiences, age composition of the population is so affected as to produce a structure akin to the result of a baby-boom. While the size of a baby-boom is measured by the magnitude and speed of fertility increase, the peak in numbers born during the transition can be measured by the magnitude and speed of fertility decline. Effects of the peaked age structure on employment, retirement, and household composition are demonstrated with some simplified proportional models. It is also shown that population aging would become phenomenal during the first quarter of the next century, due to the hastened decline of fertility since 1980.