In October, 2011, the world's population had reached another milestone, 70 billion people. The world's population has doubled and tripled throughout the years. According to the United Nations, the world's population is most likely to reach 100 billion by 2083.
             One of the reasons for the rapid population growth is technological development. If you look into charts that show how world population changes throughout time, you will clearly discover a rapid growth after every significant event in development, such as the Industrial Revolution. Every time we make another major improvement in technology, we push environmental capacity to another limit. We mined, farmed, built power plants and so on to make the earth more suitable for us to inhabit, which in turn leads to population growth.
             Another reason for population growth lays in improvement in health care. People live longer and longer these days. Back in 20th century, the world's average life expectancy was about 30 years old and now, after only 100 years, we have doubled that number. The world's average life expectancy in 2012 is 68 years old, and in some countries, like Japan, people are even expected to live over 80. With improvement in medicine and health care, we reduced the death rate dramatically, which has no doubt contributed to the population growth.
             With people living longer, we are facing another problem, population aging. Take my country, Taiwan as an example. According to Taiwan's Council for Economic Planning and Development, Taiwan's aging index is 76.8% (population age over 65 divided by population age under 15) in 2012, making it one of the world's fastest ageing countries. As a result, my country is now suffering from lack of labor, shortage of health care resources, and more. This situation is commonly seen all over the world, mostly in developed countries. And it seems that the developing countries in different areas ...