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Where will the raw materials come from?
Housing a growing population in the coming century will be an extraordinary challenge, as will the amassing of raw materials needed to build those homes and to produce a wide array of durable and non-durable goods of all kinds. We can begin to assess the magnitude of the challenge by examining global trends in four areas: population, economy, energy demand, and housing demand.
First, consider population. Figure 1 illustrates population growth through all of history. This reveals that very rapid population growth is really a recent phenomenon. The current world population is just under 6 billion. It took all of recorded history up until 1800 to reach the first billion people in the world. We reached the second billion in 130 years, or by 1930; the third billion in 35 years, or by 1965; the fourth billion in 15 years, or by 1980; the fifth billion in only 10 years, or by 1990. Fewer than 10 years will elapse before reaching the 6 billion mark.
Figure 2 shows recent and projected population growth as reported by the International Programs Center of the U.S. Census Bureau. The most likely scenario, the medium projection, is that there will be twice as many people in the world by the end of the 21st century as there are today, with most of that growth well within the lifetime of our children. The high projection, which indicates what will happen if the current birth rate is maintained, predicts 25 billion people will live in the world. Thus, the medium projection is based on the assumption that there will be a substantial reduction in the birth rate compared to current levels.
The current annual increase in world population is about 90 million people a year, or about 0.9 billion per decade, a rate that represents a bit of decline in the last few years. It's a little hard to grasp the magnitude of this kind of increase. What does 90 million more people a year mean? Perhaps it is easier to think about population increases when dealing with shorter blocks of time. For example, every hour of every day, the global population is increasing by about 10,000 people.
Where is most of...