CAMBRIDGE – The world is in the midst of the greatest demographic upheaval in human history. Although the human race took perhaps one million years to reach one billion people (around the year 1800), we have been adding successive billions every 10-20 years since 1960. The world’s population now stands at seven billion and is projected to reach 9.3 billion by 2050.
In other words, between now and 2050, the world is likely to add to its population almost as many people as populated the entire planet in 1950. Or think of it as adding another China and another India. Feeding, clothing, housing, and otherwise providing for this massive net addition to the global population is one of the main challenges facing humankind.
If we use as our guide average material progress over the course of centuries, it might seem that necessity will again serve as the mother of invention, and that we will meet the population challenge, just as we have met previous challenges, through technological and institutional innovation.
But long-term averages can mask significant volatility over time and variation across countries. We know for certain that there is great risk in the population growth that lies ahead, as nearly all of it will occur in the world’s most economically, politically, socially, and environmentally fragile countries.